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Wang S, Tong X, Zhang J, Fan Y, Wei W, Li J, Liu Y, Hu M, Chen Q, Liu L. Estimation of renal function using iodine maps in dual-energy spectral computed tomography urography: a feasibility and accuracy study. Abdom Radiol (NY) 2024; 49:997-1005. [PMID: 38244037 DOI: 10.1007/s00261-023-04146-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 01/22/2024]
Abstract
PURPOSE To explore the feasibility of measuring glomerular filtration rate (GFR) using iodine maps in dual-energy spectral computed tomography urography (DEsCTU) and correlate them with the estimated GFR (eGFR) based on the equation of creatinine-cystatin C. MATERIALS AND METHODS One hundred and twenty-eight patients referred for DEsCTU were retrospectively enrolled. The DEsCTU protocol included non-contrast, nephrographic, and excretory phase imaging. The CT-derived GFR was calculated using the above 3-phase iodine maps (CT-GFRiodine) and 120 kVp-like images (CT-GFR120kvp) separately. CT-GFRiodine and CT-GFR120kvp were compared with eGFR using paired t-test, correlation analysis, and Bland-Altman plots. The receiver operating characteristic curves were used to test the renal function diagnostic performance with CT-GFR120kvp and CT-GFRiodine. RESULTS The difference between eGFR (89.91 ± 18.45 ml·min-1·1.73 m-2) as reference standard and CT-GFRiodine (90.06 ± 20.89 ml·min-1·1.73 m-2) was not statistically significant, showing excellent correlation (r = 0.88, P < 0.001) and agreement (± 19.75 ml·min-1·1.73 m-2, P = 0.866). The correlation between eGFR and CT-GFR120kvp (66.13 ± 19.18 ml·min-1·1.73 m-2) was poor (r = 0.36, P < 0.001), and the agreement was poor (± 40.65 ml·min-1·1.73 m-2, P < 0.001). There were 62 patients with normal renal function and 66 patients with decreased renal function based on eGFR. The CT-GFRiodine had the largest area under the curve (AUC) for distinguishing between normal and decreased renal function (AUC = 0.951). CONCLUSION The GFR can be calculated accurately using iodine maps in DEsCTU. DEsCTU could be a non-invasive and reliable one-stop-shop imaging technique for evaluating both the urinary tract morphology and renal function.
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Affiliation(s)
- Shigeng Wang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Urology, Shahekou District, Lianhe Road, Dalian, China
| | - Xiaoyu Tong
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Urology, Shahekou District, Lianhe Road, Dalian, China
| | - Jingyi Zhang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Urology, Shahekou District, Lianhe Road, Dalian, China
| | - Yong Fan
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Urology, Shahekou District, Lianhe Road, Dalian, China
| | - Wei Wei
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Urology, Shahekou District, Lianhe Road, Dalian, China
| | | | - Yijun Liu
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Urology, Shahekou District, Lianhe Road, Dalian, China
| | - Mengting Hu
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Urology, Shahekou District, Lianhe Road, Dalian, China
| | - Qiye Chen
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Urology, Shahekou District, Lianhe Road, Dalian, China
| | - Lei Liu
- Urology, The First Affiliated Hospital of Dalian Medical University, Dalian, China.
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Agafonova IG, Kotelnikov VN, Geltser BI. Estimation of Renal Clearance in Hypertensive Rats According to fMRI Data. Bull Exp Biol Med 2023; 176:14-18. [PMID: 38085393 DOI: 10.1007/s10517-023-05958-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Indexed: 12/19/2023]
Abstract
Renal clearance in Wistar rats with multifactorial cardiovasorenal model of arterial hypertension was assessed by fMRI using (EPI_Diffusion_map) protocol after injection of extracellular contrast agent gadolinium Gd-DTPA. Linear regression analysis was used to assess local concentrations of the contrast agent in the abdominal aorta, kidney compartments, pelvis, and bladder areas. Detection of marker clearance in order to verify the glomerular filtration rate was performed by the RPP (Rutland-Patlak plot) method. In 3 months after hypertension modeling, glomerular filtration rate decreased by 2 times in comparison with the control (31.2±0.44 and 62.3±1.31 μl/min/100 g, respectively; p<0.001). Our findings can indicate the formation of hypertensive nephroangiosclerosis in rats with experimental arterial hypertension. It was found that kidney damage in hypertensive rats is associated with hypofiltration.
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Affiliation(s)
- I G Agafonova
- G. B. Elyakov Pacific Institute of Bioorganic Chemistry, Far East Division of the Russian Academy of Sciences, Vladivostok, Russia.
| | - V N Kotelnikov
- Far Eastern Branch of the State Research Test Institute of Military Medicine, Ministry of Defense of the Russian Federation, Vladivostok, Russia
- Far Eastern Federal University, Vladivostok, Russia
| | - B I Geltser
- Far Eastern Federal University, Vladivostok, Russia
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Kaenkangploo D, Kampa N, Jitpean S, Seesupa S, Yongvanit K. Assessment of glomerular filtration rate measurement in dogs using dynamic contrast CT compared to serum iohexol clearance. Vet Radiol Ultrasound 2021; 63:38-46. [PMID: 34637569 DOI: 10.1111/vru.13024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 11/30/2022] Open
Abstract
Dynamic contrast CT with Patlak plot analysis can be used to determine the glomerular filtration rate (GFR). However, several studies have shown different GFR values and they are most likely less than the values by the standard techniques. The purpose of this prospective, experimental, and method comparison study was to evaluate the GFR using a CT technique (CT-GFR) in 12 healthy dogs compared to serum iohexol clearance (SIC-GFR). All dogs were anesthetized and placed in the right lateral recumbency position and the caudal part was lifted inside the CT gantry. A single-slice dynamic CT of the aorta and both kidneys was scanned sequentially every 2 s for 2 min after a bolus injection (3 mL/s) of iohexol (300 mg/kg). Time attenuation curves (TAC) were constructed and the GFR per volume of kidney was calculated using the Patlak plot analysis method based on 30-120 s time intervals, and results were compared to global GFR from SIC that was determined with eight blood samples for up to 240 min. The CT-GFR value (1.85 ± 0.48 mL/min/kg) was significantly less than the SIC-GFR value (3.40 ± 0.80 mL/min/kg; P < .05). The CT-GFR was correlated with SIC-GFR by the coefficient of correlation (r) at 0.61 (P = .046). In conclusion, the CT-GFR underestimated SIC-GFR and should be used carefully. We suggest that the GFR should be calculated using the equation derived from linear regression between CT-GFR and the standard GFR method. With its own particular parameters, each institute should have its own prediction equation.
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Affiliation(s)
- Duangdaun Kaenkangploo
- Division of Surgery, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Naruepon Kampa
- Division of Surgery, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Supranee Jitpean
- Division of Surgery, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Suvaluk Seesupa
- Division of Surgery, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Karn Yongvanit
- Veterinary Teaching Hospital, Khon Kaen University, Khon Kaen, Thailand
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Jeong S, Park SB, Chang IH, Shin J, Chi BH, Park HJ, Lee ES. Estimation of renal function using kidney dynamic contrast material-enhanced CT perfusion: accuracy and feasibility. Abdom Radiol (NY) 2021; 46:2045-2051. [PMID: 33090257 DOI: 10.1007/s00261-020-02826-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/01/2020] [Accepted: 10/10/2020] [Indexed: 01/02/2023]
Abstract
PURPOSE To measure glomerular filtration rates (GFRs) using kidney dynamic contrast material-enhanced (DCE)-CT perfusion scans and correlate them with estimated GFRs (eGFRs). MATERIALS AND METHODS Split-bolus CT urography, including pre-contrast and nephrographic-excretory phase imaging, was performed with a kidney DCE-CT perfusion scan protocol. We analysed 55 patients with suspected renal disease. All CT acquisitions were obtained on a 256-slice CT scanner for 3.5 min continuously with shallow breathing. Renal volume, perfusion and permeability values were calculated using a dedicated prototype software. Based on Patlak plots, split and total renal GFR values were determined. Paired t-tests, Pearson's correlation analysis and Bland-Altman plots were used for comparisons between kidney DCE-CT perfusion scan-derived GFR (CT-GFR) and the corresponding eGFR value. The p values < 0.05 were considered statistically significant. RESULTS The mean CT-GFR was 91.19 ± 20.71 mL/min/1.73 m2. The eGFR values based on the CKD-EPI and MDRD equations were 89.64 ± 19.74 mL/min/1.73 m2 and 89.50 ± 24.89 mL/min/1.73 m2, respectively. No statistically significant differences were found between CT-GFR and eGFRs (p > 0.05). Excellent correlation and agreement between CT-GFR and eGFRs (correlation coefficient r = 0.91 for CKD-EPI and 0.84 for MDRD equations, respectively) were confirmed. CONCLUSION Kidney DCE-CT perfusion is an accurate and feasible technique to assess renal function.
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Affiliation(s)
- Seokmin Jeong
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul, 06973, Korea
| | - Sung Bin Park
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul, 06973, Korea.
| | - In Ho Chang
- Department of Urology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea
| | - Jungho Shin
- Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea
| | - Byung Hoon Chi
- Department of Urology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea
| | - Hyun Jeong Park
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul, 06973, Korea
| | - Eun Sun Lee
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul, 06973, Korea
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Assessment of Split Renal Function Using a Combination of Contrast-Enhanced CT and Serum Creatinine Values for Glomerular Filtration Rate Estimation. AJR Am J Roentgenol 2020; 215:142-147. [PMID: 32255686 DOI: 10.2214/ajr.19.22125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE. The objective of our study was to develop a novel method to estimate single-kidney glomerular filtration rate (GFR) using a combination of contrast-enhanced CT and serum creatinine (SCr) values and to validate the resulting estimated glomerular filtration rates (eGFRs) by comparing them with the single-kidney Gates GFR, which is based on renal dynamic imaging. MATERIALS AND METHODS. Sixty-two patients with asymmetric renal disease who underwent unenhanced and triphasic contrast-enhanced CT of the kidneys, 99mTc-diethylenetriamine pentaacetic acid renal dynamic imaging, and SCr testing within 1 week were retrospectively included. The eGFR was split into single-kidney GFRs of the left and right kidneys by a proportionality factor derived from the products of renal volume and CT number increments of the multiphasic CT images, which produced unenhanced phase (yielded by the renal volume proportional factor alone), arterial phase, venous phase, and nephrographic phase CT split eGFRs. The four CT split eGFRs were compared with the Gates GFR using the paired-sample t test, Pearson correlation analysis, and Bland-Altman analysis. RESULTS. Correlation coefficients and 95% CIs between the four CT split eGFRs and Gates GFR were as follows: unenhanced phase, 0.729 (95% CI, 0.626-0.805); arterial phase, 0.781 (95% CI, 0.685-0.849); venous phase, 0.788 (95% CI, 0.690-0.839); and nephrographic phase, 0.842 (95% CI, 0.758-0.902) (all, p < 0.001). The paired differences between the CT split eGFRs and Gates GFR were as follows: unenhanced phase, 2.04 ± 10.85 (95% CI, 0.01-4.07) mL/min/1.73 m2; arterial phase, 2.04 ± 10.56 (95% CI, 0.06-4.02) mL/min/1.73 m2; venous phase, 2.04 ± 10.04 (95% CI, 0.16-3.92) mL/min/1.73 m2; and nephrographic phase, 2.04 ± 8.92 (95% CI, 0.37-3.71) mL/min/1.73 m2. These results suggest a maximum deviation from the Gates GFR of ± 44.9% for the unenhanced phase eGFR, ± 43.7% for the arterial phase eGFR, ± 41.6% for the venous phase eGFR, and ± 36.9% for nephrographic phase eGFR. CONCLUSION. Split renal function can be estimated using a combination of contrast-enhanced CT and SCr values to calculate eGFR. The CT images of the nephrographic phase may be the optimal choice to use in this proposed method.
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Effects of Changes in Analytic Variables and Contrast Material on Measurement of Computed Tomography Glomerular Filtration Rates in Healthy Candidates. J Comput Assist Tomogr 2020; 44:217-222. [PMID: 31996652 DOI: 10.1097/rct.0000000000000979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE This study aimed to prospectively assess the effects of changes in analytic variables and contrast material (CM) osmolality when measuring glomerular filtration rate using computed tomography (CT-GFR). METHODS One hundred healthy participants were included in this analysis. Glomerular filtration rate was measured by technetium-99m diethylene-triamine-penta-acetic acid (Tc-DTPA), and each participant underwent CT-GFR with iodinated CM (iohexol 240 or iobitridol 400) following a crossover study design. Dynamic renal CT scanning was performed. Patlak plot analysis was used to calculate GFR, selecting either the renal cortex or the whole kidney as the region of interest. The renal cortex was analyzed just before time of the second cortical attenuation peak. The whole kidney was analyzed 60, 80, 100, and 120 seconds after the appearance of CM. Automated GFR calculations were performed using perfusion software at 2 noise reduction levels (medium and strong). The CT-GFRs were compared with GFR measured by Tc-DTPA. RESULTS There was no significant difference in CT-GFR with iohexol 240 versus iobitridol 400. The CT-GFR at the renal cortex, for the whole kidney 60 seconds after appearance of CM and calculated by perfusion software with medium noise reduction, did not differ significantly from GFR measured by Tc-DTPA. Whole-kidney CT-GFR at ≥80 seconds after CM appearance and CT-GFR calculated using perfusion CT software with strong noise reduction were lower when compared with GFR measured by Tc-DTPA. CONCLUSION Results from CT-GFR were most accurate when the kidney cortex was selected as the region of interest or when using 60-second time point for whole-kidney assessment, regardless of CM osmolarity.
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Wang T, Xu Y, Liu W, Shao P, Lv Q, Yang G, Tang L. Measurement of Glomerular Filtration Rate Using Multiphasic Computed Tomography in Patients With Unilateral Renal Tumors: A Feasibility Study. Front Physiol 2019; 10:1209. [PMID: 31607949 PMCID: PMC6761270 DOI: 10.3389/fphys.2019.01209] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 09/04/2019] [Indexed: 11/23/2022] Open
Abstract
Objectives This study was to assess the feasibility of a modified multiphasic CT scan protocol combined with homemade software measurements of glomerular filtration rate (CT-GFR) and explore the effect of renal tumor volume on the calculation of CT-GFR. Materials and Methods Prospective observational study comparing three methods of GFR measurement from February 2017 to December 2017, 91 patients with unilateral renal tumor underwent both a modified multiphasic CT scans of kidney and serum creatinine (Scr) tests preoperatively, of which 15 cases underwent additional radionuclide examination. Total and split CT-GFR, with or without renal tumor, were quantified by the homemade software in early and late renal parenchymal phases, respectively. The volume of renal tumor was quantified by the homemade software. Correlation and difference between CT-GFR and traditional methods of GFR measurement, including estimated GFR (eGFR) from Scr concentration and split GFR using of radionuclide examination (R-GFR), were performed. Results There is a strong correlation between CT-GFR with renal tumor and eGFR (r = 0.90, p < 0.001) in early renal parenchymal phase. The relative CT-GFR in early renal parenchymal phase was highly correlated with the relative R-GFR (r = 0.88, p < 0.001). Renal tumor volume significantly correlated with the value of CT-GFR that determined by subtracting the CT-GFR measurement without renal tumor from CT-GFR measurement with renal tumor (r = 0.89, p < 0.001). Conclusion A modified multiphasic CT scan protocol combined with homemade software might be an alternative technique for the evaluation of renal function for the patients with unilateral renal tumor.
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Affiliation(s)
- Tingting Wang
- Department of Nuclear Medicine, The First Affiliated Hospital, Nanjing Medical University, Nanjing, China.,Department of Heart Center, The First Affiliated Hospital, Auhui Medical University, Hefei, China
| | - Yi Xu
- Department of Radiology, The First Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Wangyan Liu
- Department of Radiology, The First Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Pengfei Shao
- Department of Urology, The First Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Qiang Lv
- Department of Urology, The First Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Guanyu Yang
- Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, Nanjing, China
| | - Lijun Tang
- Department of Nuclear Medicine, The First Affiliated Hospital, Nanjing Medical University, Nanjing, China
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Wallimann M, Richter H, Sieber-Ruckstuhl NS, Blaser A, Gent TC, Krämer SD, Santner G, Kircher PR, Dennler M. Influence of injection protocol and measurement technique on computed tomographic assessment of glomerular filtration rate in healthy Beagles. Am J Vet Res 2018; 79:1298-1305. [PMID: 30457905 DOI: 10.2460/ajvr.79.12.1298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare values of CT-derived glomerular filtration rate (GFR) determined by 3 contrast-medium injection protocols and 4 measurement techniques in healthy Beagles. ANIMALS 9 healthy Beagles (mean ± SD weight, 13.2 ± 1.6 kg). PROCEDURES Each dog underwent 3 iohexol-injection protocols (700 mg of iodine/kg administered at a constant rate over 20 seconds, 700 mg of iodine/kg administered following an exponentially decelerated injection over 20 seconds, and 350 mg of iodine/kg at a constant rate over 10 seconds) during dynamic, whole renal-volume CT in randomized order with an interval of ≥ 7 days between experiments. Values of GFR determined from Patlak plots derived by use of 4 measurement techniques (standard transverse section, optimized transverse section, dorsal reconstruction, and volume calculation techniques) were compared. RESULTS The measurement technique influenced the mean ± SD GFR results (standard transverse section technique, 2.49 ± 0.54 mL/kg/min; optimized transverse section technique, 2.72 ± 0.52 mL/kg/min; dorsal reconstruction technique, 3.00 ± 0.60 mL/kg/min, and volume calculation technique, 2.48 ± 0.51 mL/kg/min). The lower iodine dose resulted in a significantly higher GFR value (3.00 ± 0.65 mL/kg/min), compared with that achieved with either higher dose administration (constant rate injection, 2.54 ± 0.45 mL/kg/min and exponentially decelerated injection, 2.47 ± 0.48 mL/kg/min). CONCLUSIONS AND CLINICAL RELEVANCE In healthy Beagles, the CT-derived GFR measurements obtained after injection of a full dose of contrast medium were reduced, compared with measurements obtained after injection of a half dose. This finding is important with regard to potential nephrotoxicosis in dogs with impaired renal function and for GFR measurement with CT-contrast medium protocols.
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Zuo Y, Qi J, Wang G. Relative Patlak plot for dynamic PET parametric imaging without the need for early-time input function. Phys Med Biol 2018; 63:165004. [PMID: 30020080 DOI: 10.1088/1361-6560/aad444] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The Patlak graphical method is widely used in parametric imaging for modeling irreversible radiotracer kinetics in dynamic PET. The net influx rate of radiotracer can be determined from the slope of the Patlak plot. The implementation of the standard Patlak method requires the knowledge of full-time input function from the injection time until the scan end time, which presents a challenge for use in the clinic. This paper proposes a new relative Patlak plot method that does not require early-time input function and therefore can be more efficient for parametric imaging. Theoretical analysis proves that the effect of early-time input function is a constant scaling factor on the Patlak slope estimation. Thus, the parametric image of the slope of the relative Patlak plot is related to the parametric image of standard Patlak slope by a global scaling factor. This theoretical finding has been further demonstrated by computer simulation and real patient data. The study indicates that parametric imaging of the relative Patlak slope can be used as a substitute of parametric imaging of standard Patlak slope for tasks that do not require absolute quantification, such as lesion detection and tumor volume segmentation.
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Affiliation(s)
- Yang Zuo
- Department of Radiology, University of California at Davis, Sacramento, CA 95817, United States of America
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You S, Ma X, Zhang C, Li Q, Shi W, Zhang J, Yuan X. Determination of single-kidney glomerular filtration rate (GFR) with CT urography versus renal dynamic imaging Gates method. Eur Radiol 2017; 28:1077-1084. [PMID: 28971295 DOI: 10.1007/s00330-017-5061-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 08/07/2017] [Accepted: 09/06/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To present a single-kidney CT-GFR measurement and compare it with the renal dynamic imaging Gates-GFR. MATERIALS AND METHODS Thirty-six patients with hydronephrosis referred for CT urography and 99mTc-DTPA renal dynamic imaging were prospectively included. Informed consent was obtained from all patients. The CT urography protocol included non-contrast, nephrographic, and excretory phase imaging. The total CT-GFR was calculated by dividing the CT number increments of the total urinary system between the nephrographic and excretory phase by the products of iodine concentration in the aorta and the elapsed time, then multiplied by (1- Haematocrit). The total CT-GFR was then split into single-kidney CT-GFR by a left and right kidney proportionality factor. The results were compared with single-kidney Gates-GFR by using paired t-test, correlation analysis, and Bland-Altman plots. RESULTS Paired difference between single-kidney CT-GFR (45.02 ± 13.91) and single-kidney Gates-GFR (51.21 ± 14.76) was 6.19 ± 5.63 ml/min, p<0.001, demonstrating 12.1% systematic underestimation with ±11.03 ml/min (±21.5%) measurement deviation. A good correlation was revealed between both measurements (r=0.87, p<0.001). CONCLUSION The proposed single-kidney CT-GFR correlates and agrees well with the reference standard despite a systematic underestimation, therefore it could be a one-stop-shop for evaluating urinary tract morphology and split renal function. KEY POINTS • A new CT method can assess split renal function • Only using images from CT urography and the value of haematocrit • A one-stop-shop CT technique without additional radiation dose.
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Affiliation(s)
- Shan You
- Department of Graduate, Hebei North University, 11 Diamond South Road, High-tech Zone, Zhangjiakou City, Hebei Province, 075000, People's Republic of China
| | - XianWu Ma
- Department of Radiology, Qiqihar Chinese Medicine Hospital, 23 Ping An Nan Jie, Tiefeng District, Qigihar City, Heilongjiang Province, 161005, People's Republic of China
| | - ChangZhu Zhang
- Department of Radiology, Qiqihar Chinese Medicine Hospital, 23 Ping An Nan Jie, Tiefeng District, Qigihar City, Heilongjiang Province, 161005, People's Republic of China
| | - Qiang Li
- Department of Radiology, Qiqihar Chinese Medicine Hospital, 23 Ping An Nan Jie, Tiefeng District, Qigihar City, Heilongjiang Province, 161005, People's Republic of China
| | - WenWei Shi
- Department of Radiology, The 309th Hospital of Chinese People`s Liberation Army, 17 Heishanhu Road, Haidian District, Beijing, 100091, People's Republic of China
| | - Jing Zhang
- Department of Radiology, The 309th Hospital of Chinese People`s Liberation Army, 17 Heishanhu Road, Haidian District, Beijing, 100091, People's Republic of China
| | - XiaoDong Yuan
- Department of Radiology, The 309th Hospital of Chinese People`s Liberation Army, 17 Heishanhu Road, Haidian District, Beijing, 100091, People's Republic of China.
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Matsuda Y, Kishimoto M, Kushida K, Yamada K, Shimizu M, Itoh H. Effects of changes in analytic variables and contrast medium on estimation of glomerular filtration rates by computed tomography in healthy dogs. Am J Vet Res 2017; 78:1049-1055. [PMID: 28836837 DOI: 10.2460/ajvr.78.9.1049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate effects of changes in analytic variables and contrast medium osmolality on glomerular filtration rate estimated by CT (CT-GFR) in dogs. ANIMALS 4 healthy anesthetized Beagles. PROCEDURES GFR was estimated by inulin clearance, and dogs underwent CT-GFR with iodinated contrast medium (iohexol or iodixanol) in a crossover-design study. Dynamic renal CT scanning was performed. Patlak plot analysis was used to calculate GFR with the renal cortex or whole kidney selected as the region of interest. The renal cortex was analyzed just prior to time of the second cortical attenuation peak. The whole kidney was analyzed 60, 80, 100, and 120 seconds after the appearance of contrast medium. Automated GFR calculations were performed with preinstalled perfusion software including 2 noise reduction levels (medium and strong). The CT-GFRs were compared with GFR estimated by inulin clearance. RESULTS There was no significant difference in CT-GFR with iohexol versus iodixanol in any analyses. The CT-GFR at the renal cortex, CT-GFR for the whole kidney 60 seconds after appearance of contrast medium, and CT-GFR calculated by perfusion software with medium noise reduction did not differ significantly from GFR estimated by inulin clearance. The CT-GFR was underestimated at ≥ 80 seconds after contrast medium appearance (whole kidney) and when strong noise reduction was used with perfusion CT software. CONCLUSIONS AND CLINICAL RELEVANCE Selection of the renal cortex as region of interest or use of the 60-second time point for whole-kidney evaluation yielded the best CT-GFR results. The perfusion software used produced good results with appropriate noise reduction. IMPACT FOR HUMAN MEDICINE The finding that excessive noise reduction caused underestimation of CT-GFR suggests that this factor should also be considered in CT-GFR examination of human patients.
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Zhang YD, Xue CQ, Wu CJ, Tao J, Zhou WL, Shi HB. Feasibility of triphasic CT with a modified two-point Patlak plot to determine spit kidney glomerular filtration rate in clinical practice. Abdom Radiol (NY) 2017; 42:226-235. [PMID: 27503300 DOI: 10.1007/s00261-016-0858-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
PURPOSE To investigate whether triphasic CT with a simplified Patlak plot can be used in clinical practice for the estimate of split kidney glomerular filtration rate (SKGFR). MATERIALS AND METHODS The animal experiment included 15 rabbits that underwent 40 dynamic contrast-enhanced CT scans of the kidneys with 1.5 s time interval. Patlak-derived SKGFR was obtained using standard forty-point, two-point (unenhanced phase, arterial phase t α, and portovenous phase t β), and a modified two-point (MTP) (unenhanced, t α, t β, and a virtual t τ [t τ = (t α + t β)/2]) image data, respectively. The MTP-Patlak plot approach was then validated in 13 patients who underwent a triphasic renal contrast-enhanced CT examination. SKGFR measured by 99mTc-DTPA clearance was as a standard reference. RESULTS MTP-Patlak significantly reduced input function errors than two-point Patlak (21.1 ± 16.2 % vs 30.8 ± 15.2 %, p < 0.01) and showed good concordance with standard Patlak for measurement of SKGFR in animal experiment (1.20 ± 0.38 mL/g/min vs 1.51 ± 0.43 mL/g/min; linear correlation coefficient r = 0.87, p < 0.001). Human study showed that mean SKGFR was 45.7 mL/min (range, 26.5-86.2 mL/min) obtained from 99mTc-DTPA, and 38.2 mL/min (range, 18.6-79.3 mL/min) obtained from triphasic CT using MTP-Patlak plot. Linear correlation between the two methods was r = 0.75 (p < 0.01). The mean difference between SKGFRs as determined with the two methods was 7.4 ± 9.0 mL/min. CONCLUSION The MTP-Patlak approach, featured with simplicity, is feasible in a clinically indicated CT examination for the evaluation of split renal function.
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Affiliation(s)
- Yu-Dong Zhang
- Department of Radiology, The First Affiliated Hospital with Nanjing Medical University, 300, Guangzhou Road, Nanjing, 210009, Jiangsu Province, China.
| | - Chen-Qi Xue
- Department of Nuclear Medicine, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210009, China
| | - Chen-Jiang Wu
- Department of Radiology, The First Affiliated Hospital with Nanjing Medical University, 300, Guangzhou Road, Nanjing, 210009, Jiangsu Province, China
| | - Jun Tao
- Department of Urology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210009, China
| | - Wan-Li Zhou
- Department of Urology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210009, China
| | - Hai-Bin Shi
- Department of Radiology, The First Affiliated Hospital with Nanjing Medical University, 300, Guangzhou Road, Nanjing, 210009, Jiangsu Province, China
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Fifty Years of Technological Innovation: Potential and Limitations of Current Technologies in Abdominal Magnetic Resonance Imaging and Computed Tomography. Invest Radiol 2016; 50:584-93. [PMID: 26039773 DOI: 10.1097/rli.0000000000000173] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Magnetic resonance imaging (MRI) has become an important modality for the diagnosis of intra-abdominal pathology. Hardware and pulse sequence developments have made it possible to derive not only morphologic but also functional information related to organ perfusion (dynamic contrast-enhanced MRI), oxygen saturation (blood oxygen level dependent), tissue cellularity (diffusion-weighted imaging), and tissue composition (spectroscopy). These techniques enable a more specific assessment of pathologic lesions and organ functionality. Magnetic resonance imaging has thus transitioned from a purely morphologic examination to a modality from which image-based disease biomarkers can be derived. This fits well with several emerging trends in radiology, such as the need to accurately assess response to costly treatment strategies and the need to improve lesion characterization to potentially avoid biopsy. Meanwhile, the cost-effectiveness, availability, and robustness of computed tomography (CT) ensure its place as the current workhorse for clinical imaging. Although the lower soft tissue contrast of CT relative to MRI is a long-standing limitation, other disadvantages such as ionizing radiation exposure have become a matter of public concern. Nevertheless, recent technical developments such as dual-energy CT or dynamic volume perfusion CT also provide more functional imaging beyond morphology.The aim of this article was to review and discuss the most important recent technical developments in abdominal MRI and state-of-the-art CT, with an eye toward the future, providing examples of their clinical utility for the evaluation of hepatic and renal pathologies.
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Kwon SH, Lerman LO. Atherosclerotic renal artery stenosis: current status. Adv Chronic Kidney Dis 2015; 22:224-31. [PMID: 25908472 DOI: 10.1053/j.ackd.2014.10.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 12/29/2022]
Abstract
Atherosclerotic renal artery stenosis (ARAS) remains a major cause of secondary hypertension and kidney failure. Randomized prospective trials show that medical treatment should constitute the main therapeutic approach in ARAS. Regardless of intensive treatment and adequate blood pressure control, however, renal and extrarenal complications are not uncommon. Yet, the precise mechanisms, accurate detection, and optimal treatment in ARAS remain elusive. Strategies oriented to early detection and targeting these pathogenic pathways might prevent development of clinical end points. Here, we review the results of recent clinical trials, current understanding of the pathogenic mechanisms, novel imaging techniques to assess kidney damage in ARAS, and treatment options.
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Kwon SH, Saad A, Herrmann SM, Textor SC, Lerman LO. Determination of Single-Kidney Glomerular Filtration Rate in Human Subjects by Using CT. Radiology 2015; 276:490-8. [PMID: 25848903 DOI: 10.1148/radiol.2015141892] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE To test the hypothesis that computed tomography (CT)-derived measurements of single-kidney glomerular filtration rate (GFR) obtained in human subjects with 64-section CT agree with those obtained with iothalamate clearance, a rigorous reference standard. MATERIALS AND METHODS The institutional review board approved this HIPAA-compliant study, and written informed consent was obtained. Ninety-six patients (age range, 51-73 years; 46 men, 50 women) with essential (n = 56) or renovascular (n = 40) hypertension were prospectively studied in controlled conditions (involving sodium intake and renin-angiotensin blockade). Single-kidney perfusion, volume, and GFR were measured by using multidetector CT time-attenuation curves and were compared with GFR measured by using iothalamate clearance, as assigned to the right and left kidney according to relative volumes. The reproducibility of CT GFR over a 3-month period (n = 21) was assessed in patients with renal artery stenosis who were undergoing stable medical treatment. Statistical analysis included the t test, Wilcoxon signed rank test, linear regression, and Bland-Altman analysis. RESULTS CT GFR values were similar to those of iothalamate clearance (mean ± standard deviation, 38.2 mL/min ± 18 vs 41.6 mL/min ± 17; P = .062). Stenotic kidney CT GFR in patients with renal artery stenosis was lower than contralateral kidney GFR or essential hypertension single-kidney GFR (mean, 23.1 mL/min ± 13 vs 36.9 mL/min ± 17 [P = .0008] and 45.2 mL/min ± 16 [P = .019], respectively), as was iothalamate clearance (mean, 26.9 mL/min ± 14 vs 38.5 mL/min ± 15 [P = .0004] and 49.0 mL/min ± 14 [P = .001], respectively). CT GFR correlated well with iothalamate GFR (linear regression, CT GFR = 0.88*iothalamate GFR, r(2) = 0.89, P < .0001), and Bland-Altman analysis was used to confirm the agreement. CT GFR was also moderately reproducible in medically treated patients with renal artery stenosis (concordance coefficient correlation, 0.835) but was unaffected by revascularization (mean, 25.3 mL/min ± 15.2 vs 30.3 mL/min ± 18.5; P = .097). CONCLUSION CT assessments of single-kidney GFR are reproducible and agree well with a reference standard. CT can be useful to obtain minimally invasive estimates of bilateral single-kidney function in human subjects.
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Affiliation(s)
- Soon Hyo Kwon
- From the Division of Nephrology and Hypertension, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (S.H.K., A.S., S.M.H., S.C.T., L.O.L.) and Division of Nephrology, Soonchunhyang University Hospital, Seoul, South Korea (S.H.K.)
| | - Ahmed Saad
- From the Division of Nephrology and Hypertension, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (S.H.K., A.S., S.M.H., S.C.T., L.O.L.) and Division of Nephrology, Soonchunhyang University Hospital, Seoul, South Korea (S.H.K.)
| | - Sandra M Herrmann
- From the Division of Nephrology and Hypertension, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (S.H.K., A.S., S.M.H., S.C.T., L.O.L.) and Division of Nephrology, Soonchunhyang University Hospital, Seoul, South Korea (S.H.K.)
| | - Stephen C Textor
- From the Division of Nephrology and Hypertension, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (S.H.K., A.S., S.M.H., S.C.T., L.O.L.) and Division of Nephrology, Soonchunhyang University Hospital, Seoul, South Korea (S.H.K.)
| | - Lilach O Lerman
- From the Division of Nephrology and Hypertension, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (S.H.K., A.S., S.M.H., S.C.T., L.O.L.) and Division of Nephrology, Soonchunhyang University Hospital, Seoul, South Korea (S.H.K.)
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Chen B, Zhang Y, Song X, Wang X, Zhang J, Fang J. Quantitative estimation of renal function with dynamic contrast-enhanced MRI using a modified two-compartment model. PLoS One 2014; 9:e105087. [PMID: 25141138 PMCID: PMC4139329 DOI: 10.1371/journal.pone.0105087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 07/19/2014] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE To establish a simple two-compartment model for glomerular filtration rate (GFR) and renal plasma flow (RPF) estimations by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). MATERIALS AND METHODS A total of eight New Zealand white rabbits were included in DCE-MRI. The two-compartment model was modified with the impulse residue function in this study. First, the reliability of GFR measurement of the proposed model was compared with other published models in Monte Carlo simulation at different noise levels. Then, functional parameters were estimated in six healthy rabbits to test the feasibility of the new model. Moreover, in order to investigate its validity of GFR estimation, two rabbits underwent acute ischemia surgical procedure in unilateral kidney before DCE-MRI, and pixel-wise measurements were implemented to detect the cortical GFR alterations between normal and abnormal kidneys. RESULTS The lowest variability of GFR and RPF measurements were found in the proposed model in the comparison. Mean GFR was 3.03±1.1 ml/min and mean RPF was 2.64±0.5 ml/g/min in normal animals, which were in good agreement with the published values. Moreover, large GFR decline was found in dysfunction kidneys comparing to the contralateral control group. CONCLUSION Results in our study demonstrate that measurement of renal kinetic parameters based on the proposed model is feasible and it has the ability to discriminate GFR changes in healthy and diseased kidneys.
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Affiliation(s)
- Bin Chen
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yudong Zhang
- Department of Radiology, Peking University First Hospital, Beijing, China
| | - Xiaojian Song
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Department of Electrical Engineering, Chengdu University of Information Technology, Chengdu, Sichuan, China
| | - Xiaoying Wang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Department of Radiology, Peking University First Hospital, Beijing, China
- * E-mail: (XW); (JZ)
| | - Jue Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- College of Engineering, Peking University, Beijing, China
- * E-mail: (XW); (JZ)
| | - Jing Fang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- College of Engineering, Peking University, Beijing, China
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Mazzei FG, Volterrani L, Guerrini S, Cioffi Squitieri N, Sani E, Bettini G, Pozzessere C, Mazzei MA. Reduced time CT perfusion acquisitions are sufficient to measure the permeability surface area product with a deconvolution method. BIOMED RESEARCH INTERNATIONAL 2014; 2014:573268. [PMID: 25184142 PMCID: PMC4145384 DOI: 10.1155/2014/573268] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 06/22/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To reduce the radiation dose, reduced time CT perfusion (CTp) acquisitions are tested to measure permeability surface (PS) with a deconvolution method. METHODS AND MATERIALS PS was calculated with repeated measurements (n = 305) while truncating the time density curve (TDC) at different time values in 14 CTp studies using CTp 4D software (GE Healthcare, Milwaukee, WI, US). The median acquisition time of CTp studies was 59.35 sec (range 49-92 seconds). To verify the accuracy of the deconvolution algorithm, a variation of the truncated PS within the error measurements was searched, that is, within 3 standard deviations from the mean nominal error provided by the software. The test was also performed for all the remaining CTp parameters measured. RESULTS PS maximum variability happened within 25 seconds. The PS became constant after 40 seconds for the majority of the active tumors (10/11), while for necrotic tissues it was consistent within 1% after 50 seconds. A consistent result lasted for all the observed CTp parameters, as expected from their analytical dependance. CONCLUSION 40-second acquisition time could be an optimal compromise to obtain an accurate measurement of the PS and a reasonable dose exposure with a deconvolution method.
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Affiliation(s)
- Francesco Giuseppe Mazzei
- Department of Diagnostic Imaging, Azienda Ospedaliera Universitaria Senese, Viale Bracci 10, 53100 Siena, Italy
| | - Luca Volterrani
- Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy
| | - Susanna Guerrini
- Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy
| | - Nevada Cioffi Squitieri
- Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy
| | - Eleonora Sani
- Department of Physics, Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Florence, Italy
| | - Gloria Bettini
- Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy
| | - Chiara Pozzessere
- Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy
| | - Maria Antonietta Mazzei
- Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy
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Helck A, Schönermarck U, Habicht A, Notohamiprodjo M, Stangl M, Klotz E, Nikolaou K, la Fougère C, Clevert DA, Reiser M, Becker C. Determination of split renal function using dynamic CT-angiography: preliminary results. PLoS One 2014; 9:e91774. [PMID: 24618919 PMCID: PMC3950217 DOI: 10.1371/journal.pone.0091774] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 02/13/2014] [Indexed: 12/28/2022] Open
Abstract
Objectives To determine the feasibility of a dynamic CT angiography-protocol with regard to simultaneous assessment of renal anatomy and function. Methods 7 healthy potential kidney donors (58±7 years) underwent a dynamic computed tomography angiography (CTA) using a 128-slice CT-scanner with continuous bi-directional table movement, allowing the coverage of a scan range of 18 cm within 1.75 sec. Twelve scans of the kidneys (n = 14) were acquired every 3.5 seconds with the aim to simultaneously obtain CTA and renal function data. Image quality was assessed quantitatively (HU-measurements) and qualitatively (grade 1–4, 1 = best). The glomerular filtration rate (GFR) was calculated by a modified Patlak method and compared with the split renal function obtained with renal scintigraphy. Results Mean maximum attenuation was 464±58 HU, 435±48 HU and 277±29 HU in the aorta, renal arteries, and renal veins, respectively. The abdominal aorta and all renal vessels were depicted excellently (grade 1.0). The image quality score for cortex differentiation was 1.6±0.49, for the renal parenchyma 2.4±0.49. GFR obtained from dynamic CTA correlated well with renal scintigraphy with a correlation coefficient of r = 0.84; P = 0.0002 (n = 14). The average absolute deviation was 1.6 mL/min. The average effective dose was 8.96 mSv. Conclusion Comprehensive assessment of renal anatomy and function is feasible using a single dynamic CT angiography examination. The proposed protocol may help to improve management in case of asymmetric kidney function as well as to simplify evaluation of potential living kidney donors.
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Affiliation(s)
- Andreas Helck
- Institute for Clinical Radiology, University Hospital Grosshadern (LMU), Munich, Germany
- * E-mail:
| | - Ulf Schönermarck
- Department of Internal Medicine IV, University Hospital Grosshadern (LMU), Munich, Germany
| | - Antje Habicht
- Transplant Center Munich, University Hospital Grosshadern (LMU), Munich, Germany
| | - Mike Notohamiprodjo
- Institute for Clinical Radiology, University Hospital Grosshadern (LMU), Munich, Germany
| | - Manfred Stangl
- Department of Surgery, University Hospital Grosshadern (LMU), Munich, Germany
| | - Ernst Klotz
- Siemens Healthcare, Computed Tomography, Forchheim, Germany
| | - Konstantin Nikolaou
- Institute for Clinical Radiology, University Hospital Grosshadern (LMU), Munich, Germany
| | - Christian la Fougère
- Department of Nuclear Medicine, University Hospital Grosshadern (LMU), Munich, Germany
| | - Dirk Andrè Clevert
- Institute for Clinical Radiology, University Hospital Grosshadern (LMU), Munich, Germany
| | - Maximilian Reiser
- Institute for Clinical Radiology, University Hospital Grosshadern (LMU), Munich, Germany
| | - Christoph Becker
- Institute for Clinical Radiology, University Hospital Grosshadern (LMU), Munich, Germany
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Tyson R, Logsdon SA, Werre SR, Daniel GB. Estimation of feline renal volume using computed tomography and ultrasound. Vet Radiol Ultrasound 2012; 54:127-32. [PMID: 23278991 DOI: 10.1111/vru.12007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 11/14/2012] [Indexed: 11/27/2022] Open
Abstract
Renal volume estimation is an important parameter for clinical evaluation of kidneys and research applications. A time efficient, repeatable, and accurate method for volume estimation is required. The purpose of this study was to describe the accuracy of ultrasound and computed tomography (CT) for estimating feline renal volume. Standardized ultrasound and CT scans were acquired for kidneys of 12 cadaver cats, in situ. Ultrasound and CT multiplanar reconstructions were used to record renal length measurements that were then used to calculate volume using the prolate ellipsoid formula for volume estimation. In addition, CT studies were reconstructed at 1 mm, 5 mm, and 1 cm, and transferred to a workstation where the renal volume was calculated using the voxel count method (hand drawn regions of interest). The reference standard kidney volume was then determined ex vivo using water displacement with the Archimedes' principle. Ultrasound measurement of renal length accounted for approximately 87% of the variability in renal volume for the study population. The prolate ellipsoid formula exhibited proportional bias and underestimated renal volume by a median of 18.9%. Computed tomography volume estimates using the voxel count method with hand-traced regions of interest provided the most accurate results, with increasing accuracy for smaller voxel sizes in grossly normal kidneys (-10.1 to 0.6%). Findings from this study supported the use of CT and the voxel count method for estimating feline renal volume in future clinical and research studies.
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Affiliation(s)
- Reid Tyson
- Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061, USA.
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20
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Schmidt DM, Scrivani PV, Dykes NL, Goldstein RM, Erb HN, Reeves AP. Comparison of glomerular filtration rate determined by use of single-slice dynamic computed tomography and scintigraphy in cats. Am J Vet Res 2012; 73:463-9. [PMID: 22452491 DOI: 10.2460/ajvr.73.4.463] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare estimation of glomerular filtration rate determined via conventional methods (ie, scintigraphy and plasma clearance of technetium Tc 99m pentetate) and dynamic single-slice computed tomography (CT). ANIMALS 8 healthy adult cats. PROCEDURES Scintigraphy, plasma clearance testing, and dynamic CT were performed on each cat on the same day; order of examinations was randomized. Separate observers performed GFR calculations for scintigraphy, plasma clearance testing, or dynamic CT. Methods were compared via Bland-Altman plots and considered interchangeable and acceptable when the 95% limits of agreement (mean difference between methods ± 1.96 SD of the differences) were ≤ 0.7 mL/min/kg. RESULTS Global GFR differed < 0.7 mL/min/kg in 5 of 8 cats when comparing plasma clearance testing and dynamic CT; the limits of agreement were 1.4 and -1.7 mL/min/kg. The mean ± SD difference was -0.2 ± 0.8 mL/min/kg, and the maximum difference was 1.6 mL/min/kg. The mean ± SD difference (absolute value) for percentage filtration by individual kidneys was 2.4 ± 10.5% when comparing scintigraphy and dynamic CT; the maximum difference was 20%, and the limits of agreement were 18% and 23% (absolute value). CONCLUSIONS AND CLINICAL RELEVANCE GFR estimation via dynamic CT exceeded the definition for acceptable clinical use, compared with results for conventional methods, which was likely attributable to sample size and preventable technical complications. Because 5 of 8 cats had comparable values between methods, further investigation of dynamic CT in a larger sample population with a wide range of GFR values should be performed.
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Affiliation(s)
- David M Schmidt
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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21
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Apport de la tomodensitométrie par rayons X dans l’évaluation de la performance rénale. Nephrol Ther 2012; 8:206-11. [DOI: 10.1016/j.nephro.2011.07.413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 06/20/2011] [Accepted: 07/17/2011] [Indexed: 11/16/2022]
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Granger LA, Armbrust LJ, Rankin DC, Ghering R, Bello NM, Alexander K. Estimation of glomerular filtration rate in healthy cats using single-slice dynamic CT and Patlak plot analysis. Vet Radiol Ultrasound 2011; 53:181-8. [PMID: 22182065 DOI: 10.1111/j.1740-8261.2011.01899.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Commonly used clinical indicators of renal disease are either insensitive to early dysfunction or have delayed results. Decreased glomerular filtration rate (GFR) indicates renal dysfunction before there is a loss of 50% of functional nephrons. Most tests evaluate global rather than individual kidney function. Dynamic computed tomography (CT) and Patlak plot analysis allows for individual GFR to be tested. Our objectives were to establish a procedure and provide reference values for determination of global GFR in 10 healthy cats using dynamic CT (CTGFR). This method of GFR determination was compared against serum iohexol clearance (SIC). A single CT slice centered on both kidneys and the aorta was acquired every fifth second during and after a bolus injection of iohexol (240 mgI/ml; 300 mgI/kg) for 115 s. Using data from this dynamic acquisition, Patlak plots were obtained, GFR was calculated, and results were compared to global GFR determined by iohexol clearance. The average global CTGFR estimate was 1.84 ml/min x kg (SD = 0.43; range = [1.22, 2.45]). The average global GFR measured using SIC was 2.45 ml/min x kg (SD = 0.58; range = [1.72, 3.69]). GFR measurements estimated by both dynamic CT and SIC were positively associated (estimated Spearman rank correlation coefficient = 0.72; P = 0.0234). The CTGFR method consistently underestimated GFR with a bias of -0.62 (SE = 0.1307) when compared to SIC (P = 0.0011). In healthy cats, CTGFR was capable of determining individual kidney function and appears clinically promising.
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Affiliation(s)
- L Abbigail Granger
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, 1800 Denison Ave., Manhattan, KS 66506, USA.
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Mehra VC, Ambrose M, Valdiviezo-Schlomp C, Schuleri KH, Lardo AC, Lima JAC, George RT. CT-Based Myocardial Perfusion Imaging-Practical Considerations: Acquisition, Image Analysis, Interpretation, and Challenges. J Cardiovasc Transl Res 2011; 4:437-48. [DOI: 10.1007/s12265-011-9286-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 05/06/2011] [Indexed: 12/19/2022]
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Jones RA, Votaw JR, Salman K, Sharma P, Lurie C, Kalb B, Martin DR. Magnetic resonance imaging evaluation of renal structure and function related to disease: Technical review of image acquisition, postprocessing, and mathematical modeling steps. J Magn Reson Imaging 2011; 33:1270-83. [DOI: 10.1002/jmri.22335] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Sourbron SP, Buckley DL. On the scope and interpretation of the Tofts models for DCE-MRI. Magn Reson Med 2011; 66:735-45. [PMID: 21384424 DOI: 10.1002/mrm.22861] [Citation(s) in RCA: 267] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 12/13/2010] [Accepted: 01/10/2011] [Indexed: 11/06/2022]
Abstract
The Tofts model (TM) and extended Tofts model (ETM) have become a standard for the analysis of dynamic contrast-enhanced MRI. In this study, a mathematical analysis is used to identify exactly in which tissue types the Tofts models may be applied. The results show that the TM is accurate if and only if the tissue is weakly vascularised (small blood volume). The ETM is additionally accurate in highly perfused tissues (high blood flow). In tissues that are highly vascularised, or where tracer exchange is very fast or very slow, TM and ETM accurately fit the data but lead to a misinterpretation of the parameters. In tissue types with intermediate vascularity, perfusion and tracer exchange, neither model offers a good fit to the tissue concentrations. A good fit can be obtained with a measured input function by reducing the temporal resolution, but this does not improve the accuracy of the parameters. In conclusion, the Tofts models only produce reliable parameter values if the tissue is weakly vascularized (TM or ETM) or highly perfused (ETM). Without prior knowledge that at least one of these constraints is fulfilled, the physiological interpretation of the values produced by the Tofts models is unclear.
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Affiliation(s)
- Steven P Sourbron
- Division of Medical Physics, University of Leeds, Leeds, United Kingdom.
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Grenier N, Quaia E, Prasad PV, Juillard L. Radiology Imaging of Renal Structure and Function by Computed Tomography, Magnetic Resonance Imaging, and Ultrasound. Semin Nucl Med 2011; 41:45-60. [DOI: 10.1053/j.semnuclmed.2010.09.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Automated measurement method and tool of glomerular filtration rate using triphasic helical computed tomography images. Urology 2010; 77:1259-64. [PMID: 21185066 DOI: 10.1016/j.urology.2010.09.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 08/26/2010] [Accepted: 09/16/2010] [Indexed: 11/21/2022]
Abstract
OBJECTIVES To introduce an automated method to perform computed tomography-based glomerular filtration rate (CT GFR) measurement using the 2-point Patlak plot technique and triphasic helical CT images. We also evaluated the correlation between our automated method and the manual measurement results, as well as the results from cystatin C. METHODS The present study included 25 patients without an acute renal disorder. The CT scan protocol consisted of an unenhanced CT examination followed by 2 contrast-enhanced CT examinations in the arterial and parenchymal phase. Between the noncontrast scan and the arterial scan, 7 dynamic scans were obtained to provide more data on the arterial input function. The 2-point Patlak plot technique was used in the automated and manual measurement methods. For each patient, the cystatin C level, determined in blood samples, was used as a reference. RESULTS The correlation between our automated method and the cystatin C method in 25 patients was 0.8029 (P < .001). The correlation between the manually implemented CT GFR method and the cystatin C method was 0.8287 (P < .001). A strong correlation (r = .9518, P < .001) was seen between the automated and manual measurements using the same model; however, the automated process can be finished within 2 minutes. CONCLUSIONS The automated CT GFR measurement method could potentially be used because of its highly improved efficiency. Moreover, it would avoid the use of a differential renal nuclear study. This would be helpful for predicting the residual GFR after nephrectomy and could also be used to predict the residual GFR after partial nephrectomy for tumor or stone treatment.
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Valdiviezo C, Ambrose M, Mehra V, Lardo AC, Lima JAC, George RT. Quantitative and qualitative analysis and interpretation of CT perfusion imaging. J Nucl Cardiol 2010; 17:1091-100. [PMID: 20924735 DOI: 10.1007/s12350-010-9291-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Coronary artery disease (CAD) remains the leading cause of death in the United States. Rest and stress myocardial perfusion imaging has an important role in the non-invasive risk stratification of patients with CAD. However, diagnostic accuracies have been limited, which has led to the development of several myocardial perfusion imaging techniques. Among them, myocardial computed tomography perfusion imaging (CTP) is especially interesting as it has the unique capability of providing anatomic- as well as coronary stenosis-related functional data when combined with computed tomography angiography (CTA). The primary aim of this article is to review the qualitative, semi-quantitative, and quantitative analysis approaches to CTP imaging. In doing so, we will describe the image data required for each analysis and discuss the advantages and disadvantages of each approach.
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Affiliation(s)
- Carolina Valdiviezo
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
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Alexander K, Dunn M, Carmel EN, Lavoie JP, Del Castillo JRE. Clinical application of Patlak plot CT-GFR in animals with upper urinary tract disease. Vet Radiol Ultrasound 2010; 51:421-7. [PMID: 20806874 DOI: 10.1111/j.1740-8261.2010.01670.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Glomerular filtration rate (GFR), an important parameter of renal function, is difficult to assess clinically. Serum creatinine and blood urea nitrogen measurements lack sensitivity, whereas radionuclide determination of GFR is not always available and requires postinjection patient isolation. GFR can be determined using computed tomography (CT), most commonly via Patlak plot analysis. Four adult cats, two adult dogs, and a foal underwent abdominal CT under general anesthesia for various diseases of the upper urinary tract. CT-GFR was measured with a single-slice dynamic acquisition and Patlak plot analysis. In five animals, the total CT-GFR appeared to be below normal, corresponding with mild (two animals) and moderate (two animals) increases of serum creatinine in four. In the two animals with normal or increased CT-GFR, serum creatinine was within the reference values. A significant negative logarithmic relationship was found between CT-GFR and serum creatinine values (P = 0.008; r2 = 0.75). No complications occurred during or following CT-GFR. CT examination provided clinically relevant information in 3/5 patients with possible ureteral obstruction and in 3/3 patients with suspected ureteral calculi. Single-slice dynamic CT-GFR was practical and provided clinically useful information in this small series of patients undergoing CT of the upper urinary tract. There was a significant relationship between CT-GFR and serum creatinine values, which supports the clinical potential of CT-GFR and justifies further investigation of this technique.
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Affiliation(s)
- Kate Alexander
- Département de Sciences Cliniques, Faculté de médecine vétérinaire, Université de Montréal, PO Box 5000, St-Hyacinthe, QC, Canada J2S 7C6.
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Wang E, Sandoval RM, Campos SB, Molitoris BA. Rapid diagnosis and quantification of acute kidney injury using fluorescent ratio-metric determination of glomerular filtration rate in the rat. Am J Physiol Renal Physiol 2010; 299:F1048-55. [PMID: 20685826 DOI: 10.1152/ajprenal.00691.2009] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The rapid diagnosis and quantification of acute kidney injury (AKI) severity remain high clinical priorities. By combining intravital fluorescent ratiometric two-photon kidney imaging and the two-compartment pharmacokinetics model, we demonstrate that rapid quantification of glomerular filtration rate (GFR) can be achieved in physiologic and AKI rat kidney models. Using a bolus infusion of a mixture of FITC-inulin and a 500-kDa Texas Red dextran, a full spectrum of GFR values, ranging from 0.17 to 1.12 ml·min(-1)·100 g(-1), was obtained. The GFR values thus determined correlated well with values obtained by the standard 2-h inulin infusion clearance method with a Pearson's correlation coefficient of 0.85. In addition, postischemia deterioration was studied by measuring GFR using the two-photon approach during 24 h following a 45-min bilateral ischemia clamp model. The GFR was found to decline sharply during the initial 4 h followed by a nadir with little sign of rising over the ensuing 24-h period. Moreover, a FITC-labeled 5-kDa dextran was identified as having nearly identical filtration characteristics as FITC-inulin, but had markedly increased fluorescent intensity, thus minimizing the quantity needed for individual studies. The technique reported allows for very rapid GFR determinations, within 10-15 min, based on plasma clearance of a freely filtered fluorescence probe, instead of a prolonged one-compartment interstitial space reporter molecule clearance employed by other technologies.
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Affiliation(s)
- Exing Wang
- Nephrology Div., Dept. of Medicine, Indiana Univ. School of Medicine, Indianapolis, IN 46202, USA
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Sourbron S. Compartmental modelling for magnetic resonance renography. Z Med Phys 2010; 20:101-14. [DOI: 10.1016/j.zemedi.2009.10.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Revised: 10/27/2009] [Accepted: 10/30/2009] [Indexed: 11/24/2022]
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Alexander K, Authier S, del Castillo JRE, Arora V, Qi S, Guillot M, Beauchamp G, Troncy E. Patlak plot analysis CT-GFR for the determination of renal function: comparison of normal dogs with autologous kidney transplant dogs. CONTRAST MEDIA & MOLECULAR IMAGING 2010; 5:133-9. [DOI: 10.1002/cmmi.372] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kaplon DM, Lasser MS, Sigman M, Haleblian GE, Pareek G. Renal parenchyma thickness: a rapid estimation of renal function on computed tomography. Int Braz J Urol 2009; 35:3-8. [PMID: 19254392 DOI: 10.1590/s1677-55382009000100002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2008] [Indexed: 11/21/2022] Open
Abstract
PURPOSE To define the relationship between renal parenchyma thickness (RPT) on computed tomography and renal function on nuclear renography in chronically obstructed renal units (ORUs) and to define a minimal thickness ratio associated with adequate function. MATERIALS AND METHODS Twenty-eight consecutive patients undergoing both nuclear renography and CT during a six-month period between 2004 and 2006 were included. All patients that had a diagnosis of unilateral obstruction were included for analysis. RPT was measured in the following manner: The parenchyma thickness at three discrete levels of each kidney was measured using calipers on a CT workstation. The mean of these three measurements was defined as RPT. The renal parenchyma thickness ratio of the ORUs and non-obstructed renal unit (NORUs) was calculated and this was compared to the observed function on Mag-3 lasix Renogram. RESULTS A total of 28 patients were evaluated. Mean parenchyma thickness was 1.82 cm and 2.25 cm in the ORUs and NORUs, respectively. The mean relative renal function of ORUs was 39%. Linear regression analysis comparing renogram function to RPT ratio revealed a correlation coefficient of 0.48 (p < 0.001). The linear regression equation was computed as Renal Function = 0.48 + 0.80 * RPT ratio. A thickness ratio of 0.68 correlated with 20% renal function. CONCLUSION RPT on computed tomography appears to be a powerful predictor of relative renal function in ORUs. Assessment of RPT is a useful and readily available clinical tool for surgical decision making (renal salvage therapy versus nephrectomy) in patients with ORUs.
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Affiliation(s)
- Daniel M Kaplon
- Department of Surgery, Division of Urology, Section of Minimally Invasive Urologic Surgery, The Warren Alpert School of Medicine of Brown University, Providence, Rhode Island, USA.
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Ichihara T, Ishida M, Kitagawa K, Ichikawa Y, Natsume T, Yamaki N, Maeda H, Takeda K, Sakuma H. Quantitative analysis of first-pass contrast-enhanced myocardial perfusion MRI using a Patlak plot method and blood saturation correction. Magn Reson Med 2009; 62:373-83. [PMID: 19353669 DOI: 10.1002/mrm.22018] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The objectives of this study were to develop a method for quantifying myocardial K(1) and blood flow (MBF) with minimal operator interaction by using a Patlak plot method and to compare the MBF obtained by perfusion MRI with that from coronary sinus blood flow in the resting state. A method that can correct for the nonlinearity of the blood time-signal intensity curve on perfusion MR images was developed. Myocardial perfusion MR images were acquired with a saturation-recovery balanced turbo field-echo sequence in 10 patients. Coronary sinus blood flow was determined by phase-contrast cine MRI, and the average MBF was calculated as coronary sinus blood flow divided by left ventricular (LV) mass obtained by cine MRI. Patlak plot analysis was performed using the saturation-corrected blood time-signal intensity curve as an input function and the regional myocardial time-signal intensity curve as an output function. The mean MBF obtained by perfusion MRI was 86 +/- 25 ml/min/100 g, showing good agreement with MBF calculated from coronary sinus blood flow (89 +/- 30 ml/min/100 g, r = 0.74). The mean coefficient of variation for measuring regional MBF in 16 LV myocardial segments was 0.11. The current method using Patlak plot permits quantification of MBF with operator interaction limited to tracing the LV wall contours, registration, and time delays.
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Affiliation(s)
- Takashi Ichihara
- Department of Radiology, Mie University School of Medicine, Tsu, Mie, Japan
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Vivier PH, Blondiaux E, Dolores M, Marouteau-Pasquier N, Brasseur M, Petitjean C, Dacher JN. [Functional MR urography in children]. ACTA ACUST UNITED AC 2009; 90:11-9. [PMID: 19182709 DOI: 10.1016/s0221-0363(09)70073-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
MR Urography (MRU) provides both morphologic and functional information without radiation exposure. It enables the assessment of split renal function, excretion, and quantification of obstruction. MRU is thus complementary to ultrasonography in the assessment of pre- and post-natal obstructive uropathies in children. If available, MRU should be definitely preferred to intravenous urography.
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Affiliation(s)
- P H Vivier
- Service de Radiologie, CHU C. Nicolle, 1, rue de Germont, 76031 Rouen Cedex, France
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Bokacheva L, Rusinek H, Zhang JL, Chen Q, Lee VS. Estimates of glomerular filtration rate from MR renography and tracer kinetic models. J Magn Reson Imaging 2009; 29:371-82. [PMID: 19161190 DOI: 10.1002/jmri.21642] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
PURPOSE To compare six methods for calculating the single-kidney glomerular filtration rate (GFR) from T(1)-weighted magnetic resonance (MR) renography (MRR) against reference radionuclide measurements. MATERIALS AND METHODS In 10 patients, GFR was determined using six published methods: the Baumann-Rudin model (BR), the Patlak-Rutland method (PR), the two-compartment model without bolus dispersion (2C) and with dispersion (2CD), the three-compartment model (3CD), and the distributed parameter model (3C-IRF). Reference single-kidney GFRs were measured by radionuclide renography. The coefficient of variation of GFR (CV) was determined for each method by Monte Carlo analyses for one healthy and one dysfunctional kidney at a noise level (sigma(n)) of 2%, 5%, and 10%. RESULTS GFR estimates in patients varied from 6% overestimation (BR) to 50% underestimation (PR and 2CD applied to cortical data). Correlations with reference GFRs ranged from R = 0.74 (2CD, cortical data) to R = 0.85 (BR). In simulations, the lowest CV was produced by 3C-IRF in healthy kidney (1.7sigma(n)) and by PR in diseased kidney ((2.2-2.4)sigma(n)). In both kidneys the highest CV was obtained with 2CD ((5.9-8.2)sigma(n)) and with 3CD in diseased kidney (8.9sigma(n) at sigma(n) = 10%). CONCLUSION GFR estimates depend on the renal model and type of data used. Two- and three-compartment models produce comparable GFR correlations.
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Affiliation(s)
- Louisa Bokacheva
- Department of Radiology, New York University School of Medicine, New York, NY, USA.
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Murase K, Tachibana A, Kusakabe Y, Matsuura R, Miyazaki S. A method for quantitative assessment of renal function using dynamic contrast-enhanced computed tomography: evaluation of drug-induced nephrotoxicity in rats. Med Phys 2009; 35:5768-76. [PMID: 19175134 DOI: 10.1118/1.3020595] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The authors developed a method to quantitatively evaluate renal function using dynamic contrast-enhanced computed tomography (DCE-CT) and a compartment model. They applied this method to evaluation of drug-induced nephrotoxicity in rats. They performed the DCE-CT studies using a total of 36 male Sprague-Dawley rats (n=9 for control and n=27 for treatment). The rats in the drug-treated groups were given 1.8 mg/kg/day of cis-dichlorodiammineplatinum (cisplatin) intraperitoneally every other day twice (n=9), four times (n=9), or six times (n=9). The rate constants for the transfer of the contrast agent (CA) from the intravascular space to the renal corpuscle and tubular space via glomerular filtration (K1), outflow of the CA from the renal tubules (k2), and the fraction of blood volume (f) were estimated from the DCE-CT data, and their functional images were generated using the linear least squares method. When estimating the above parameters, the partial volume effect (PVE) on the arterial input function was corrected using a calibration curve obtained by phantom experiments. The endogenous creatinine clearance (Ccr) was also measured for comparison. The K1 images became lower and more heterogeneous and the K1 values decreased significantly with increasing cisplatin injection number (3.20+/-0.73, 2.49+/-0.75, 1.80+/-0.36, and 1.27+/-0.47 ml/ml/min for control, two-, four-, and six-times treated groups, respectively). When the PVE was not corrected, the K1 values were overestimated by 15+/-3% as compared with the case when the PVE was corrected. There was a good correlation between K1 and Ccr (r=0.903 and 0.901 for cases with and without correction of PVE, respectively). In conclusion, the authors' method using DCE-CT appears to be useful for quantitatively evaluating the extent of renal dysfunction such as renal damage due to drug-induced nephrotoxicity.
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Affiliation(s)
- Kenya Murase
- Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
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Alexander K, Ybarra N, del Castillo JRE, Morin V, Gauvin D, Bichot S, Beauchamp G, Troncy É. Determination of glomerular filtration rate in anesthetized pigs by use of three-phase whole-kidney computed tomography and Patlak plot analysis. Am J Vet Res 2008; 69:1455-62. [DOI: 10.2460/ajvr.69.11.1455] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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In vitro assessment of a 3D segmentation algorithm based on the belief functions theory in calculating renal volumes by MRI. AJR Am J Roentgenol 2008; 191:W127-34. [PMID: 18716080 DOI: 10.2214/ajr.07.3063] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Renal volumetry is an essential part of split renal function assessment in MR urography. The aim of this study was to assess the accuracy and repeatability of a 3D segmentation algorithm based on the belief functions theory for calculating renal volumes from MR images. MATERIALS AND METHODS The true volumes of 20 animal kidneys of various sizes were obtained by fluid displacement. Each kidney was examined using two different MR units. Three-dimensional proton density-weighted acquisitions with an incremental slice thickness were performed. The MR volume was then measured with a segmentation algorithm based on the belief functions theory. Two independent observers performed all segmentations twice. Accuracy, intraobserver variability, and interobserver variability were evaluated by the Bland-Altman method. The number and type of manual corrections were recorded as well as the entire processing time. RESULTS The mean renal volume estimated by fluid displacement was 114 mL (range, 38-224 mL). With regard to the renal volumes obtained from assessments of adjacent axial MR images, the maximal SDs of the difference were 2.2 mL (accuracy), 0.6 mL (intraobserver variability), and 1.8 mL (interobserver variability). Segmentation of axial slices provided better accuracy and reproducibility than coronal slices. Overlapped coronal slices yielded poor results because of the partial volume effect. The mean processing time including optional manual modifications was less than 75 seconds. CONCLUSION The belief functions theory can be considered an accurate and reproducible mathematic method to assess renal volume from MR adjacent images.
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He W, Fischman AJ. Nuclear imaging in the genitourinary tract: recent advances and future directions. Radiol Clin North Am 2008; 46:25-43, v. [PMID: 18328878 DOI: 10.1016/j.rcl.2008.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For almost three decades, noninvasive radionuclide procedures for the evaluation of renal disease have been important components of nuclear medicine practice. With the introduction of new imaging agents and procedures, these techniques can provide valuable data on perfusion and function of individual kidneys. In general, these procedures are easy to perform and carry a low radiation burden and sedation is not required. Moreover, radionuclide imaging of the genitourinary tract has become an invaluable asset to clinicians in the evaluation of renal parenchyma and urologic abnormalities.
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Affiliation(s)
- Wei He
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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Alexander K, Del Castillo JRE, Ybarra N, Morin V, Gauvin D, Authier S, Vinay P, Troncy E. Single-slice dynamic computed tomographic determination of glomerular filtration rate by use of Patlak plot analysis in anesthetized pigs. Am J Vet Res 2007; 68:297-304. [PMID: 17331020 DOI: 10.2460/ajvr.68.3.297] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare glomerular filtration rate (GFR) as estimated from Patlak plot analysis by use of single-slice computed tomography (CT) with that obtained from clearance of plasma inulin in pigs. ANIMALS 8 healthy anesthetized juvenile pigs. PROCEDURES All pigs underwent precontrast, whole-kidney, helical CT; postcontrast single-slice dynamic CT; and postcontrast, whole-kidney CT for volume determination. On dynamic images, corrected Hounsfield unit values were determined for each kidney and the aorta. A Patlak plot for each kidney was generated, and plasma clearance per unit volume was multiplied by renal volume to obtain whole-animal contrast clearance. Mean GFR determined via inulin clearance (Inu-GFR) was measured from each kidney and correlated to mean GFR determined via CT (CT-GFR) for the left kidney, right kidney, and both kidneys by use of linear regression and Bland-Altman analyses. RESULTS CT-GFR results from 7 pigs were valid. Total and right kidney Inu-GFR were correlated with total and right kidney CT-GFR (total, R(2) = 0.85; right kidney, R(2) = 0.86). However, left kidney CT-GFR was poorly correlated with left kidney Inu-GFR (R(2) = 0.47). Bland-Altman analysis revealed no significant bias between Inu-GFR and CT-GFR for the left kidney, right kidney, or both kidneys. CONCLUSIONS AND CLINICAL RELEVANCE CT-GFR as determined by use of a single-slice acquisition technique, low-dose of iohexol, and Patlak plot analysis correlated without bias with Inu-GFR for the right kidney and both kidneys (combined). This technique has promise as an accurate CT-GFR method that can be combined with renal morphologic evaluation.
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Affiliation(s)
- Kate Alexander
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 7C6, Canada
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Hackstein N, Buch T, Rau WS, Weimer R, Klett R. Split renal function measured by triphasic helical CT. Eur J Radiol 2007; 61:303-9. [PMID: 17011152 DOI: 10.1016/j.ejrad.2006.09.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Revised: 08/26/2006] [Accepted: 09/01/2006] [Indexed: 11/27/2022]
Abstract
PURPOSE To present a method for calculating split renal function solely from routine triphasic helical computed tomography (CT). SUBJECTS AND METHODS We retrospectively included 26 adult patients who received renal scintigraphy and triphasic CT within 4 weeks in the years 2003 and 2004. All scans were performed using a standard abdominal protocol. Split renal function was calculated as relative single-kidney glomerular filtration rate (GFR) using a simplified "two-point Patlak plot" technique. As a reference method, split renal function was determined from renal scintigraphy using the standard technique. RESULTS Linear correlation between the two methods was r=0.91, split renal function (CT)=0.0266+0.9573 x split renal function (scintigraphy). CONCLUSION Split renal function can be measured accurately by minimally extended triphasic CT.
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Affiliation(s)
- Nils Hackstein
- Radiologische Gemeinschaftspraxis am Evangelischen Krankenhaus, Paul-Zipp-Str. 171, 35398 Giessen, Germany.
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Abstract
Daghini et al used a pig model to estimate single-kidney GFR with dynamic contrast-enhanced CT scanning. Three techniques were evaluated, two of which (the modified Patlak method and the gamma variate model) yielded GFR estimates that correlated significantly with determinations made by using standard inulin clearance techniques. The findings hold promise that noninvasive in vivo assessment of single-kidney renal function may be achieved in patients.
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Affiliation(s)
- F Graham Sommer
- Department of Radiology, Stanford University Medical Center, 300 Pasteur Dr, H-1307, Stanford, CA 94305-5105, USA.
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Daghini E, Juillard L, Haas JA, Krier JD, Romero JC, Lerman LO. Comparison of Mathematic Models for Assessment of Glomerular Filtration Rate with Electron-Beam CT in Pigs. Radiology 2007; 242:417-24. [PMID: 17255413 DOI: 10.1148/radiol.2422052144] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To prospectively compare in pigs three mathematic models for assessment of glomerular filtration rate (GFR) on electron-beam (EB) computed tomographic (CT) images, with concurrent inulin clearance serving as the reference standard. MATERIALS AND METHODS This study was approved by the institutional animal care and use committee. Inulin clearance was measured in nine pigs (18 kidneys) and compared with single-kidney GFR assessed from renal time-attenuation curves (TACs) obtained with EB CT before and after infusion of the vasodilator acetylcholine. CT-derived GFR was calculated with the original and modified Patlak methods and with previously validated extended gamma variate modeling of first-pass cortical TACs. Statistical analysis was performed to assess correlation between CT methods and inulin clearance for estimation of GFR with least-squares regression analysis and Bland-Altman graphical representation. Comparisons within groups were performed with a paired t test. RESULTS GFR assessed with the original Patlak method indicated poor correlation with inulin clearance, whereas GFR assessed with the modified Patlak method (P < .001, r = 0.75) and with gamma variate modeling (P < .001, r = 0.79) correlated significantly with inulin clearance and indicated an increase in response to acetylcholine. CONCLUSION CT-derived estimates of GFR can be significantly improved by modifications in image analysis methods (eg, use of a cortical region of interest).
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Affiliation(s)
- Elena Daghini
- Division of Nephrology and Hypertension and Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, 200 First St SW, Rochester, MN 55905, USA
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Hackstein N, Kooijman H, Tomaselli S, Rau WS. Glomerular filtration rate measured using the Patlak plot technique and contrast-enhanced dynamic MRI with different amounts of gadolinium-DTPA. J Magn Reson Imaging 2006; 22:406-14. [PMID: 16106358 DOI: 10.1002/jmri.20401] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We determined the optimum gadolinium (Gd)-DTPA dose and time window for calculating the glomerular filtration rate (GFR) using contrast-enhanced (CE) dynamic MRI and the Patlak plot technique. Twelve adult volunteers with healthy kidneys were included in the study. As a reference method the GFR was measured by iopromide plasma clearance. A three-dimensional gradient-echo (GRE) sequence with a flip angle of 50 degrees was used for MRI. Signal was measured using a body surface coil with four elements. Each volunteer was examined on four days using 2 mL, 4 mL, 8 mL, or 16 mL of Gd-DTPA 0.5 mmol/mL dissolved with sodium chloride (NaCl) 0.9% to a total of 60 mL. The injection rate was 1 mL/second. A Patlak plot was calculated from the kidney and aorta signals. The mean reference GFR was 133 mL/min (min-max, 116-153 mL/min). The best correlation of GFR calculated from MRI data compared to the reference method was found in a time window 30-90 seconds after aortic signal rise using 16 mL Gd-DTPA. Pearson's correlation coefficient was r = 0.83, and the standard deviation (SD) from the line of regression was 10.5 mL/minute. We found a significantly lower average GFR(MR) using 16 mL Gd-DTPA compared to 4 mL and 2 mL in the late time window 60-120 seconds post aortic rise. A dose of 16 mL Gd-DTPA was optimal for measuring GFR using dynamic MRI and the Patlak plot technique. The slope should be measured in a time window of 30-90 seconds post aortic rise.
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Affiliation(s)
- Nils Hackstein
- Department of Diagnostic Radiology, Justus-Liebig Universität Giessen, Germany.
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Levin YS, Chow LC, Pelc NJ, Sommer FG, Spielman DM. Estimation of renal extraction fraction based on postcontrast venous and arterial differentialT1 values: An error analysis. Magn Reson Med 2005; 54:309-16. [PMID: 16032662 DOI: 10.1002/mrm.20548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An error analysis for quantifying single kidney extraction fraction (EF) via differential T1 measurements in the renal vein (RV) and renal artery (RA) is presented. Sources of error include blood flow effects, the effect of a short repetition time (TR), and the impact of uncertainties in the T1 estimates on the final EF calculations. Blood flow effects were investigated via simulation. For a range of blood velocities in the renal vein that may be found in kidney disease, incomplete refreshment of blood between readouts results in significant errors in T1 estimation. For a .5-cm slice, 110-ms sampling interval, and T1 of 600 ms, T1 estimation to within 5% of true T1 requires an average through-plane velocity of 6.75 cm/s for parabolic flow, and 3.5 cm/s for plug flow. Improvement can be achieved by accurately estimating the fraction of blood that has not refreshed between readouts (f(old)), while the quality of the T1 estimate varies with the accuracy of f(old) estimation. Shortening of the TR was investigated using phantom and in vivo studies. T1 was estimated to within 3% of the true value on phantoms, and within 5% of the true value for flowing blood for TR = 2T1. The estimated EF is shown to be very sensitive to the difference between T(1RA) and T(1RV). To achieve 10% or 20% uncertainty in the EF estimate, T1 in the renal vein and renal artery must be estimated to within approximately 1% or 2%. Because of limitations on measurement accuracy and precision, this method appears to be impractical at this time.
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Affiliation(s)
- Yakir S Levin
- Department of Electrical Engineering, Stanford University, Stanford, California, USA.
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Gates GF. Filtration Fraction and its Implications for Radionuclide Renography Using Diethylenetriaminepentaacetic Acid and Mercaptoacetyltriglycine. Clin Nucl Med 2004; 29:231-7. [PMID: 15096969 DOI: 10.1097/01.rlu.0000117998.67737.ae] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were determined in 92 patients to calculate filtration fraction (GFR/EFPR) and evaluate its change in renal diseases. This information was used as the rationale for a renogram protocol using DTPA (to estimate GFR) and MAG3 (to produce images and curves). METHODS Individual kidney GFR and ERPF were determined by gamma camera techniques using Tc-99m DTPA and I-131 OIH. Two hundred sixty-one determinations were performed in 92 patients who in turn were grouped into 4 categories: normal, obstruction, renal vascular disease, and chronic insufficiency. RESULTS Mean filtration fractions in normal patients and those with obstruction were similar (0.16 and 0.15, respectively), whereas they were lower in renal vascular disease (0.11) and chronic renal insufficiency (0.08). Low filtration fraction indicates disproportionate loss of GFR compared with ERPF and was the pattern observed with advancing renal disease in most patients. The exception was ATN or contrast nephropathy when filtration fraction was increased (0.22) as a result of disproportionate loss of ERPF compared with GFR. CONCLUSIONS OIH is no longer available in the United States, and MAG3 is now used as the renal tubular agent in renography. Clearance of MAG3 does not directly measure ERPF, but this might not be a significant loss in clinical practice if GFR is measured during renography because it is more adversely affected by renal disease than ERPF (with the exception of ATN and contrast nephropathy). Accordingly, a renogram protocol is presented for the combined use of DTPA and MAG3 resulting in GFR estimation (from DTPA) while yielding superior renal images and renogram curves from MAG3.
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Affiliation(s)
- Gary F Gates
- Nuclear Medicine Department, Providence St. Vincent Medical Center, Portland, OR 97225, USA.
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Hackstein N, Heckrodt J, Rau WS. Measurement of single-kidney glomerular filtration rate using a contrast-enhanced dynamic gradient-echo sequence and the Rutland-Patlak plot technique. J Magn Reson Imaging 2004; 18:714-25. [PMID: 14635157 DOI: 10.1002/jmri.10410] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To determine the accuracy of single-kidney glomerular filtration rate (GFR) determination using contrast-enhanced dynamic magnetic resonance imaging (MRI) and the Rutland-Patlak plot technique. MATERIALS AND METHODS Twenty-eight adult patients were included. As reference method, the GFR was measured by plasma clearance using a small bolus injection of iopromide. A three-dimensional gradient-echo (GRE) sequence with a flip angle of 50 degrees was used for MRI; this showed a good linear relationship between gadolinium (Gd)-DTPA concentration and signal change when measured up to a Gd-DTPA concentration of 10 mmol/liter. A slab containing both kidneys and the abdominal aorta was measured 30 times in approximately 3.5 minutes. During this measurement, 15 mL of Gd-DTPA, 0.5 mol/liter diluted to a volume of 60 mL, was injected over 60 seconds. A Rutland-Patlak plot was calculated from the signal changes in the aorta and the renal parenchyma. Single-kidney GFR was calculated for different time windows from the Rutland-Patlak plot slope. RESULTS The best correlation compared to the reference method was found with the GFR calculated from the slope of the Rutland-Patlak plot 40-110 seconds postaortic rise. Pearson's correlation coefficient was r = 0.86, SD was 14.8 mL/minute. In many of the patients, a decrease of the renal signal was observed in the excretory phase, which was probably caused by very high Gd-DTPA concentrations in the collecting tubules. CONCLUSION Single-kidney GFR can be calculated from dynamic contrast-enhanced MRI. We found a promising correlation of global GFR calculated by MRI compared to the reference method. In any future study, the amount of Gd-DTPA should by reduced to avoid artificial signal drop in the excretory phase induced by the T2* effect.
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Affiliation(s)
- Nils Hackstein
- Department of Diagnostic Radiology, Justus-Liebig Universität Giessen, Giessen, Germany.
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Annet L, Hermoye L, Peeters F, Jamar F, Dehoux JP, Van Beers BE. Glomerular filtration rate: Assessment with dynamic contrast-enhanced MRI and a cortical-compartment model in the rabbit kidney. J Magn Reson Imaging 2004; 20:843-9. [PMID: 15503326 DOI: 10.1002/jmri.20173] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To describe the use of MRI and a cortical-compartment model to measure the glomerular filtration rate (GFR), and compare the results with those obtained with the Patlak-Rutland model. MATERIALS AND METHODS Dynamic MRI of rabbit kidneys was performed during and after injection of gadoterate dimeglumine. The enhancement curves in the aorta and the kidney were analyzed with the cortical-compartment and Patlak-Rutland models to assess the GFR. RESULTS A substantial correlation was observed between the GFR measured with MRI using the cortical-compartment model and the plasma clearance of 51Cr-EDTA (r=0.821, P=0.004). No significant correlation was observed between the 51Cr-EDTA clearance (r=0.628, P=0.052) and the GFR obtained with the Patlak-Rutland model in regions of interest (ROIs) encompassing the renal cortex and medulla. A Bland and Altman analysis showed that GFR(cortical) (compartment) agreed better with the 51Cr-EDTA clearance compared to GFR(Patlak) when ROIs were limited to the cortex. However, the GFR values obtained by MRI were lower than the plasma clearance of 51Cr-EDTA. CONCLUSION MRI with a cortical-compartment model provides more accurate assessments of glomerular filtration than the Patlak-Rutland model.
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Affiliation(s)
- Laurence Annet
- Department of Radiology, Université Catholique de Louvain, Cliniques Universitaires St.-Luc, Brussels, Belgium.
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