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Lee VS, Johnston JD, Massey AP, DeVaneaux C. Comparison of a Face-to-Face verses Virtual World Weight Loss Program. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000401987.11558.c6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Zhou XP, Lee VS, Wang EQ, Jiang JJ. Evaluation of the effects of deep brain stimulation of the subthalamic nucleus and levodopa treatment on parkinsonian voice using perturbation, nonlinear dynamic, and perceptual analysis. Folia Phoniatr Logop 2009; 61:189-99. [PMID: 19590218 PMCID: PMC4821425 DOI: 10.1159/000227996] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS To quantify aperiodic phonation, nonlinear dynamic methods of acoustic voice analysis, such as correlation dimension, have been shown to be useful. The purpose of this study is to evaluate the validity of nonlinear dynamic analysis as a voice analysis tool for the effects of deep brain stimulation (DBS) and levodopa on patients with Parkinson's disease (PD). METHODS In this study, the effects of DBS and levodopa treatment on patients with PD were measured using perturbation, nonlinear dynamic, and perceptual analysis. Nineteen PD patients that received bilateral (n = 9), left (n = 7), or right (n = 3) DBS performed sustained vowel phonations, which were recorded before and after medication with the stimulator off and on. Recordings were also taken of 10 PD patients who did not receive DBS surgery before and after medication to provide a baseline. RESULTS A mixed two-way ANOVA (surgery, medication) generated significant positive treatment effects of DBS only in mean log-transformed D2, which was supported by mean log-transformed shimmer, vF0 (variability in fundamental frequency), and vAm (peak-to-peak amplitude variation). CONCLUSION These findings may indicate the validity of nonlinear dynamic analysis as a complement to perceptual analysis in clinical PD voice studies.
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Lee VS, Zhou XP, Rahn DA, Wang EQ, Jiang JJ. Perturbation and nonlinear dynamic analysis of acoustic phonatory signal in Parkinsonian patients receiving deep brain stimulation. JOURNAL OF COMMUNICATION DISORDERS 2008; 41:485-500. [PMID: 18433765 PMCID: PMC3313602 DOI: 10.1016/j.jcomdis.2008.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 01/22/2008] [Accepted: 02/23/2008] [Indexed: 05/26/2023]
Abstract
UNLABELLED Nineteen PD patients who received deep brain stimulation (DBS), 10 non-surgical (control) PD patients, and 11 non-pathologic age- and gender-matched subjects performed sustained vowel phonations. The following acoustic measures were obtained on the sustained vowel phonations: correlation dimension (D2), percent jitter, percent shimmer, SNR, F0, vF0, and vAm. The results indicated the following: The mean D2 of control PD patients was significantly higher than the mean D2 of non-pathologic subjects and patients who received deep brain stimulation. These results suggest an improvement in PD voice in treated patients. Many PD vocal samples in this study have type 2 signals containing subharmonics that may not be suitable for perturbation analysis but are suitable for nonlinear dynamic analysis, making the D2 results more reliable. These findings show that DBS may provide measurable improvement in patients with severe vocal impairment. LEARNING OUTCOMES Readers will be able to: (1) identify the advantages of nonlinear dynamic analysis as a clinical tool to evaluate the aperiodic voice commonly found in patients with Parkinson's disease, (2) describe in general the method of obtaining a correlation dimension measure from a voice sample and the significance of this measure in terms of specific voice signal properties, (3) consider the preliminary implications from nonlinear dynamic analysis of a positive DBS effect on Parkinsonian voice and the potential for further investigations using nonlinear dynamic analysis on the influence of gender, severity of disease, and combined treatments on Parkinsonian voice improvement.
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Lee VS. Reflections on a summer internship in public health. WMJ : OFFICIAL PUBLICATION OF THE STATE MEDICAL SOCIETY OF WISCONSIN 2008; 107:10-11. [PMID: 18416362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Chang ET, Canchola AJ, Lee VS, Clarke CA, Horn-Ross PL. Wine and Other Alcohol Consumption and Risk of Ovarian Cancer. Am J Epidemiol 2006. [DOI: 10.1093/aje/163.suppl_11.s114-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Bokacheva L, Huang AJ, Chen Q, Oesingmann N, Storey P, Rusinek H, Lee VS. Single breath-holdT1 measurement using low flip angle TrueFISP. Magn Reson Med 2006; 55:1186-90. [PMID: 16572392 DOI: 10.1002/mrm.20845] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A method for estimating T1 using a single breath-hold, segmented, inversion recovery prepared, true fast imaging with steady-state precession (sIR-TrueFISP) acquisition at low flip angle (FA) was implemented in this study. T1 values measured by sIR-TrueFISP technique in a Gd-DTPA-doped water phantom and the human brain and abdomen of healthy volunteers were compared with the results of the standard IR fast spin echo (FSE) technique. A good correlation between the two methods was observed (R2=0.999 in the phantom, and R2=0.943 in the brain and abdominal tissues). The T1 values of the tissues agreed well with published results. sIR-TrueFISP enables fast measurements of T1 to be obtained within a single breath-hold with good accuracy, which is particularly important for chest and abdominal imaging.
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Ng HW, Teo EC, Lee VS. Statistical factorial analysis on the material property sensitivity of the mechanical responses of the C4–C6 under compression, anterior and posterior shear. J Biomech 2004; 37:771-7. [PMID: 15047007 DOI: 10.1016/j.jbiomech.2003.09.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2003] [Indexed: 11/22/2022]
Abstract
A systematic approach using factorial analysis was conducted on the C4-C6 finite element model to analyse the influence of six spinal components (cortical shell, vertebral body, posterior elements, endplate, disc annulus and disc nucleus) on the internal stresses and external biomechanical responses under compression, anterior and posterior shear. Results indicated that the material properties variation of the disc annulus has a significant influence on both the external biomechanical responses and internal stress of the disc annulus and its neighboring hard bones. The study reveals for the first time, the significant influence of the cancellous bone under compression, while variation in the cortical shell modulus has a high influence under anterior and posterior shear. The study also reveals that the effects of interaction between two main components are insignificant.
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Lee VS, Rusinek H, Johnson G, Rofsky NM, Krinsky GA, Weinreb JC. MR renography with low-dose gadopentetate dimeglumine: feasibility. Radiology 2001; 221:371-9. [PMID: 11687678 DOI: 10.1148/radiol.2212010142] [Citation(s) in RCA: 58] [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 develop a low-dose magnetic resonance (MR) renographic method performed with and without an angiotensin converting enzyme (ACE) inhibitor and in conjunction with gadolinium-enhanced MR angiography in patients with suspected renovascular disease. MATERIALS AND METHODS Thirty-two patients underwent MR renography (turbo fast low-angle shot sequence: repetition time, 5 msec; echo time, 2.3 msec; flip angle, 15 degrees; one coronal image acquired every 2 seconds for 4 minutes) following intravenous injection of 2 mL of gadopentetate dimeglumine, which was repeated following intravenous injection of an ACE inhibitor. Contrast material-enhanced MR angiography was also performed. On the basis of renographic findings, renal cortex and renal medulla enhancement curves and normalized enhancement ratios were analyzed. RESULTS The cortex and medulla showed an early transient period of enhancement within 20 seconds (vascular phase). During 1-2 minutes, a second, gradual increase in medullary enhancement, reflecting transit of filtered contrast material, was observed that was significantly greater in patients with a serum creatinine level less than 2 mg/dL (177 micromol/L) than in those with a level of 2 mg/dL or greater (P < .01). After injection of the ACE inhibitor, patients with elevated creatinine levels showed low renal medullary enhancement regardless of the presence of renal artery stenosis (RAS). However, in patients with creatinine less than 2 mg/dL, medullary enhancement ratios after injection of the ACE inhibitor were consistently lower in patients with RAS of 50% or greater than in those without stenosis (P = .02 to .08). CONCLUSION Low-dose MR renography can be performed in the clinical setting before and after injection of an ACE inhibitor, and its potential use for evaluating decreased renal function as a consequence of RAS is promising.
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Pandharipande PV, Lee VS, Morgan GR, Teperman LW, Krinsky GA, Rofsky NM, Roy MC, Weinreb JC. Vascular and extravascular complications of liver transplantation: comprehensive evaluation with three-dimensional contrast-enhanced volumetric MR imaging and MR cholangiopancreatography. AJR Am J Roentgenol 2001; 177:1101-7. [PMID: 11641180 DOI: 10.2214/ajr.177.5.1771101] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Our purpose was to evaluate a comprehensive MR imaging strategy for recipients of liver transplants that relies on dynamic interpolated three-dimensional (3D) MR imaging for simultaneous vascular, parenchymal, and extrahepatic imaging. MATERIALS AND METHODS Twenty-three consecutive adult patients underwent 30 MR imaging examinations between 2 days and 99 months (mean, 15 months) after transplantation using a breath-hold 3D gradient-echo sequence (TR range/TE range, 3.7-4.7/1.8-1.9; flip angle, 12-30 degrees ) with an intermittent fat-saturation pulse and interpolation in the section-select direction to enable pixel size 3 mm or less in all dimensions. Unenhanced and triphasic contrast-enhanced 3D imaging (average dose, 0.13 mmol/kg of gadopentetate dimeglumine) was performed. A subset of patients (n = 13) also underwent MR cholangiopancreatography using half-Fourier single-shot turbo spin-echo imaging. MR imaging examinations were correlated with digital subtraction angiography (n = 8), contrast-enhanced cholangiography (n = 9), sonography (n = 13), and histopathology (n = 14). RESULTS MR imaging revealed abnormal findings in 27 (90%) of 30 examinations, including vascular disease in nine, biliary complications in four, and evidence of intra- or extra-hepatic hepatocellular carcinoma recurrence in six. Digital subtraction angiography confirmed seven MR angiography examinations but suggested disease overestimation in one. Contrast-enhanced cholangiography confirmed findings of MR cholangiopancreatography in seven cases but suggested disease underestimation in two. CONCLUSION Dynamic interpolated 3D MR imaging combined with dedicated MR cholangiopancreatography can provide a comprehensive assessment of vascular, biliary, parenchymal, and extrahepatic complications in most recipients of liver transplants.
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Lee VS, Lavelle MT, Krinsky GA, Rofsky NM. Volumetric MR imaging of the liver and applications. Magn Reson Imaging Clin N Am 2001; 9:697-716, v-vi. [PMID: 11694434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Recent improvements in MR technology have enabled the development of volumetric three-dimensional (3D) imaging methods for fat-suppressed T1-weighted images of the entire upper abdomen with pixel sizes of approximately 2 mm in all dimensions and with acquisition times of less than 25 seconds for breath-hold imaging. When performed with a timing scheme, dynamic contrast-enhanced volumetric imaging of the liver can be performed with selective imaging during the arterial phase and portal venous phase of enhancement. The volumetric data sets can be reconstructed in any oblique plane, enabling improved detection, localization, and characterization of small liver lesions. The combination of high-resolution isotropic pixels and accurate timing also permits angiographic reconstructions of the 3D images, producing MR angiography and venography that can be useful in therapeutic planning, such as for catheter-based interventions or surgical resections or transplantation. Additionally, with use of a hepatobiliary contrast agent such as mangafodipir, T1-weighted volumetric MR cholangiography can be performed in patients with nonobstructed systems for depiction of intrahepatic biliary anatomy.
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Wetzel SG, Lee VS, Tan AG, Heid O, Cha S, Johnson G, Rofsky NM. Real-time interactive duplex MR measurements: application in neurovascular imaging. AJR Am J Roentgenol 2001; 177:703-7. [PMID: 11517079 DOI: 10.2214/ajr.177.3.1770703] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Real-time interactive duplex MR imaging is a new phase-contrast MR imaging technique that enables the quantification and display of flow velocities in real time without the need for cardiac gating. We investigated the feasibility and reliability of the technique to assess hemodynamic information both in vitro and in vivo in the carotid arteries and in the venous sinuses. SUBJECTS AND METHODS Real-time interactive duplex MR measurements (TR/TE, 53/27; flip angle, 90 degrees; encoding velocity, 100 or 150 cm/sec) were performed in vitro with a steady-flow phantom and in 10 healthy volunteers in whom common and internal carotid artery velocities were measured. In eight volunteers, velocity measurements were also performed in the superior sagittal sinus during both normal breathing and hyperventilation. Time-velocity plots were analyzed qualitatively and quantitatively and compared with findings from conventional segmented k-space phase-contrast MR imaging and Doppler sonography. RESULTS Velocity determinations for real-time duplex MR and conventional phase-contrast MR imaging showed an in vitro correlation of 0.99 and an in vivo correlation of 0.83 (carotid arteries) and 0.76 (venous sinus). Velocity measurements in the carotid arteries with real-time MR imaging were significantly lower than those obtained with conventional phase-contrast MR (averaged, 7.8%; p = 0.003) or sonography (23.7%, p < 0.001), likely because of volume averaging. Small but significant velocity changes occurring in the venous sinus during hyperventilation were reliably identified with both MR techniques. CONCLUSION Real-time interactive duplex MR imaging can be effectively applied in neurovascular imaging to obtain hemodynamic information.
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Abstract
The relationship between the administered dose d of Gd-DTPA and the accuracy of measurements of the glomerular filtration rate G and the cardiac output O was investigated. For a wide range of values the concentration of Gd-DTPA can be uniquely derived from MR signals and precontrast longitudinal relaxation time. Fixed and random errors in these measured variables were analyzed. Depending on noise level and the level of renal function, errors in G reach a minimum for d = 1.4-2.8 mmol. Random errors in G are relatively insensitive to d as long as d > 1.5 mmol. These results establish the feasibility of dynamic MR measurements using doses of Gd-DTPA that are several times lower than current standards.
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Lee VS, Morgan GR, Teperman LW, John D, Diflo T, Pandharipande PV, Berman PM, Lavelle MT, Krinsky GA, Rofsky NM, Schlossberg P, Weinreb JC. MR imaging as the sole preoperative imaging modality for right hepatectomy: a prospective study of living adult-to-adult liver donor candidates. AJR Am J Roentgenol 2001; 176:1475-82. [PMID: 11373217 DOI: 10.2214/ajr.176.6.1761475] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Our aim was to investigate the feasibility of MR imaging as a comprehensive preoperative imaging test for examination of liver donor candidates for adult-to-adult right lobe transplantation. SUBJECTS AND METHODS Twenty-five consecutive donor candidates were examined at 1.5 T using a torso phased array coil with breath-hold T1- and T2-weighted imaging of the abdomen, MR cholangiography using T2-weighted turbo spin-echo imaging, and MR angiography and venography of the liver using two interpolated three-dimensional spoiled gradient-echo sequences (average dose of gadolinium contrast material, 0.17 mmol/kg). Images were interpreted for liver parenchymal and extrahepatic abnormalities; measurements of right and left lobe liver volumes; definition of hepatic arterial, portal venous, and hepatic venous anatomy; and definition of the biliary branching pattern. Findings were compared with those of conventional angiography in 13 patients, 11 of whom also had surgical findings for comparison. RESULTS Nine patients were excluded as candidates for donation on the basis of MR imaging findings that included parenchymal or extrahepatic abnormalities in five patients, vascular anomalies in two, and biliary anomalies in three. Two patients who did not undergo surgery underwent conventional angiography that confirmed MR angiographic findings except for a small (<2 mm) accessory left hepatic artery missed on MR imaging. Of the nine patients who underwent successful right hepatectomy, all MR imaging findings were corroborated intraoperatively. In two patients, right hepatectomy was aborted at laparotomy because of intraoperative cholangiography findings; in one of them, the biliary finding was unsuspected on MR imaging. CONCLUSION A comprehensive MR imaging examination has the potential to serve as the sole preoperative imaging modality for living adult-to-adult liver donor candidates provided improvements in definition of intrahepatic biliary anatomy can be achieved.
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Krinsky GA, Freedberg R, Lee VS, Rockman C, Tunick PA. Innominate artery atheroma: a lesion seen with gadolinium-enhanced MR angiography and often missed by transesophageal echocardiography. Clin Imaging 2001; 25:251-7. [PMID: 11566085 DOI: 10.1016/s0899-7071(01)00292-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Transesophageal echocardiography (TEE) is the procedure of choice for identifying aortic atheromas, which may result in stroke, transient ischemic attack and peripheral embolization. However, because of anatomic constraints, the innominate artery may not be visualized. We investigated gadolinium-enhanced MR angiography (MRA) as an alternative technique for evaluation of suspected atheromas of the innominate artery. From a retrospective review of 520 examinations, we identified five patients who had innominate artery atheromas diagnosed prospectively with gadolinium-enhanced MRA who also underwent TEE within 1 month. A total of 10 innominate artery atheromas were demonstrated on MRA; none of these were visualized on TEE. One patient had three atheromas, two patients had two atheromas and three patients had one atheroma. They ranged in size from 3 mm to 1.5 cm (mean 6.5 mm). One atheroma was flat, two were filiform, and seven were protruding. Gadolinium-enhanced MRA is superior to TEE for the diagnosis of atheromas of the innominate artery. In the setting of right cerebral or right arm embolization, when no source is seen in the arch on TEE, gadolinium-enhanced MRA should be considered.
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Krinsky GA, Lee VS, Theise ND, Weinreb JC, Rofsky NM, Diflo T, Teperman LW. Hepatocellular carcinoma and dysplastic nodules in patients with cirrhosis: prospective diagnosis with MR imaging and explantation correlation. Radiology 2001; 219:445-54. [PMID: 11323471 DOI: 10.1148/radiology.219.2.r01ma40445] [Citation(s) in RCA: 273] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE To determine the sensitivity and specificity of magnetic resonance (MR) imaging for detection of hepatocellular carcinoma (HCC) and dysplastic nodules (DNs) by using explantation correlation in patients with cirrhosis and no known HCC. MATERIALS AND METHODS Seventy-one patients without a known history of HCC who underwent MR imaging and subsequent transplantation within 90 days were examined. Breath-hold turbo short inversion time inversion-recovery and/or T2-weighted turbo spin-echo MR images were obtained. Dynamic two- or three-dimensional gadolinium-enhanced gradient-echo MR images were obtained in the hepatic arterial, portal venous, and equilibrium phases. Prospective MR image interpretations were compared directly with explanted liver pathologic results. RESULTS Eleven (15%) of 71 patients had hepatic malignancies; MR imaging enabled diagnosis of tumor in six (54%) of 11 patients. On a lesion-by-lesion basis, MR imaging depicted 11 of 20 hepatic neoplasms, for an overall sensitivity of 55%. MR imaging depicted four (80%) of five lesions larger than 2 cm, six (50%) of 12 lesions 1-2 cm, and one (33%) of three lesions smaller than 1 cm. MR imaging depicted only nine (15%) of 59 DNS: The specificities of MR imaging for detection of HCC and DNs on a per patient basis were 60 (86%) of 70 patients and 53 (85%) of 62 patients, respectively. CONCLUSION MR imaging is insensitive for the diagnosis of small (<2-cm) HCCs and DNS:
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Lee VS, Rofsky NM, Morgan GR, Teperman LW, Krinsky GA, Berman P, Weinreb JC. Volumetric mangafodipir trisodium-enhanced cholangiography to define intrahepatic biliary anatomy. AJR Am J Roentgenol 2001; 176:906-8. [PMID: 11264075 DOI: 10.2214/ajr.176.4.1760906] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Díaz Candamio MJ, Lee VS, Rofsky NM, Krinsky GA, Weinreb JC. Pelvic arteriovenous malformations: gadolinium-enhanced three-dimensional MR angiography findings. Eur Radiol 2001; 10:1257-60. [PMID: 10939485 DOI: 10.1007/s003300000329] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pelvic arteriovenous malformations (PAV-Ms) are rare disorders traditionally diagnosed by conventional angiography. Breath-hold three-dimensional gadolinium-enhanced MR angiography (3D-Gd-MRA) is a state-of-the-art alternative for vascular imaging. We describe the 3D-Gd-MRA findings in two patients with PAVMs. The 3D-Gd-MRA approach provides a noninvasive and versatile method for evaluation of PAVMs that enables both angiographic assessment of the malformations and evaluation of visceral involvement, which can preclude surgical intervention.
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Lavelle MT, Lee VS, Rofsky NM, Krinsky GA, Weinreb JC. Dynamic contrast-enhanced three-dimensional MR imaging of liver parenchyma: source images and angiographic reconstructions to define hepatic arterial anatomy. Radiology 2001; 218:389-94. [PMID: 11161151 DOI: 10.1148/radiology.218.2.r01fe31389] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
PURPOSE To assess the accuracy of an interpolated breath-hold T1-weighted three-dimensional (3D) gradient-echo (GRE) magnetic resonance (MR) imaging sequence with near-isotropic pixel size (</=2.3 mm) for evaluation of hepatic arterial anatomy variants during dynamic liver parenchymal imaging and to report patterns of hepatic arterial anatomy. MATERIALS AND METHODS Liver MR imaging, including an interpolated breath-hold 3D GRE sequence with fat suppression (4.2/1.8 [repetition time msec/echo time msec], 12 degrees flip angle), was performed in 207 consecutive patients before and after gadopentetate dimeglumine administration. Of the 207 patients, 202 (98%) had technically satisfactory studies clearly defining the hepatic arterial system. The first contrast material-enhanced GRE acquisition was timed for optimal arterial enhancement with a timing examination. In a retrospective review, hepatic arteries were evaluated on the basis of arterial phase images interpreted by two independent readers using transverse source images complemented by multiplanar reconstructions. Twenty-three patients also underwent digital subtraction angiography, which was a reference standard for comparison. RESULTS Conventional hepatic arterial anatomy was demonstrated in 135 (67%) of 202 patients. In the 23 patients with angiographic correlation, no discrepancy was noted between MR imaging and digital subtraction angiographic findings. CONCLUSION Hepatic arterial anatomy can be reliably demonstrated during liver parenchymal imaging with an optimally timed contrast-enhanced isotropic 3D GRE sequence.
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Krinsky GA, Lee VS, Nguyen MT, Rofsky NM, Theise ND, Morgan GR, Teperman LW, Weinreb JC. Siderotic nodules in the cirrhotic liver at MR imaging with explant correlation: no increased frequency of dysplastic nodules and hepatocellular carcinoma. Radiology 2001; 218:47-53. [PMID: 11152778 DOI: 10.1148/radiology.218.1.r01ja4047] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PURPOSE To determine the sensitivity of magnetic resonance (MR) imaging for detection of siderotic nodules in patients with cirrhosis and whether the frequency of hepatocellular carcinoma (HCC) and dysplastic nodules is greater if siderotic nodules are present. MATERIALS AND METHODS MR imaging (1.5 T) was performed within 0-117 days (mean, 30 days) before liver transplantation in 77 patients. Two readers retrospectively evaluated gradient-echo (GRE) (echo time [TE], > or = 9 and 4-5 msec) and turbo short inversion time inversion-recovery or T2-weighted images for low-signal-intensity nodules. Whole-explant pathologic correlation was available in every case. RESULTS At explantation, 28 (36%) of 77 patients had HCC, 25 (32%) had dysplastic nodules, and nine (12%) had both; 35 (45%) patients had siderotic nodules. The sensitivity of GRE imaging with 9-msec or longer TE for the detection of siderotic nodules was 80% (28 of 35) but decreased to 31% (11 of 35) with 4-5-msec TE. Frequency of HCC was not significantly higher (P =.27) in patients with (43% [15 of 35]) than in patients without (31% [13 of 42]) siderotic nodules. Frequency of dysplastic nodules also was not significantly higher (P =.42) in patients with (37% [13 of 35]) than in patients without (29% [12 of 42]) siderotic nodules. CONCLUSION Sensitivity of MR imaging for the detection of siderotic nodules was improved with use of GRE pulse sequences with longer TEs of 9 msec or greater (80%) versus 4-5 msec (31%); however, there was no significant increased frequency of HCC or dysplastic nodules in patients with pathologically proved siderotic nodules.
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Krinsky GA, Lee VS, Nguyen MT, Rofsky NM, Theise ND, Morgan GR, Teperman LW, Weinreb JC. Siderotic nodules at MR imaging: regenerative or dysplastic? J Comput Assist Tomogr 2000; 24:773-6. [PMID: 11045701 DOI: 10.1097/00004728-200009000-00019] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE To determine if iron containing "siderotic" nodules detected at magnetic resonance (MR) imaging are regenerative (RN) or dysplastic (DN) and to attempt to identify features that may distinguish them. MATERIAL AND METHODS MR imaging (1.5 T) was performed on 77 cirrhotic patients who underwent orthotopic liver transplantation within 0-117 days (mean 30 days) of MR imaging. Two readers retrospectively evaluated breath-hold gradient-echo pulse sequences (echo time > or =9.0 ms, flip angle < or =45 degrees) for the presence of hypointense nodules, which were classified as micronodular (< or =3 mm), macronodular (>3 mm), or mixed. Nodule distribution was classified as focal (<5), scattered (5-20), or diffuse (>20) per slice. Thin section pathologic correlation was available in all cases, and Prussian blue iron stains were performed. RESULTS Of 35 patients with pathologically proven siderotic nodules, 10 (29%) had at least 2 siderotic DN. MR detected siderotic nodules in 10 of 10 (100%) patients with siderotic DN and RN, and in 18 of 25 patients (72%) with siderotic RN only. CONCLUSION Siderotic RN cannot be reliably distinguished from siderotic DN with MR imaging, and therefore the widely used term "siderotic regenerative nodule" should be avoided and replaced by "siderotic nodule."
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Lee VS, Martin DJ, Krinsky GA, Rofsky NM. Gadolinium-enhanced MR angiography: artifacts and pitfalls. AJR Am J Roentgenol 2000; 175:197-205. [PMID: 10882274 DOI: 10.2214/ajr.175.1.1750197] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Krinsky GA, Nguyen MT, Lee VS, Rosen RJ, Goldenberg A, Theise ND, Morgan G, Rofsky NM. Dysplastic nodules and hepatocellular carcinoma: sensitivity of digital subtraction hepatic arteriography with whole liver explant correlation. J Comput Assist Tomogr 2000; 24:628-34. [PMID: 10966200 DOI: 10.1097/00004728-200007000-00022] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE The purpose of this work was to determine the sensitivity of hepatic digital subtraction arteriography (DSA) for the detection of hepatocellular carcinoma (HCC) and dysplastic nodules (DNs) when compared with pathological findings from whole liver explants. METHOD Twenty-one patients 30-72 years old (mean 54 years) with cirrhosis and known or clinically suspected HCC (20 prior to chemoembolization) underwent hepatic DSA with subsequent transplantation within 80 days (mean 32 days). The prospective DSA report was compared with pathologic findings from explanted livers. RESULTS Overall, DSA detected 31 of 95 HCC lesions for a sensitivity of 33%. Of these 31 lesions, 28 were hypervascular and 3 were hypovascular. DSA detected all six HCCs measuring >5 cm, all six HCCs measuring 3-5 cm, and all five HCCs 2-3 cm, resulting in a sensitivity of 100% (17/17) for HCC >2 cm. DSA detected 7 of 18 HCCs measuring 1-2 cm (sensitivity 39%) and 7 of 60 HCCs < or =1 cm (sensitivity 12%). Overall sensitivity for DSA in detection of HCC < or =2 cm was 18% (14/78 lesions). None of 17 DNs (0.2-1.5 cm in size) was identified on DSA. CONCLUSION DSA is insensitive to small HCC (< or =2 cm), carcinomatosis arising within nodules, and DN.
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Sobue T, Lee VS, Ye W, Tanooka H, Mifune M, Suyama A, Koga T, Morishima H, Kondo S. Residential randon exposure and lung cancer risk in Misasa, Japan: a case-control study. JOURNAL OF RADIATION RESEARCH 2000; 41:81-92. [PMID: 11037576 DOI: 10.1269/jrr.41.81] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In order to investigate an association between residential radon exposure and risk of lung cancer, a case-control study was conducted in Misasa Town, Tottori Prefecture, Japan. The case series consisted of 28 people who had died of lung cancer in the years 1976-96 and 36 controls chosen randomly from the residents in 1976, matched by sex and year of birth. Individual residential radon concentrations were measured for 1 year with alpha track detectors. The average radon concentration was 46 Bq/m3 for cases and 51 Bq/m3 for controls. Compared to the level of 24 or less Bq/m3, the adjusted odds ratios of lung cancer associated with radon levels of 25-49, 50-99 and 100 or more Bq/m3, were 1.13 (95% confidence interval; 0.29-4.40), 1.23 (0.16-9.39) and 0.25 (0.03-2.33), respectively. None of the estimates showed statistical significance, due to small sample size. When the subjects were limited to only include residents of more than 30 years, the estimates did not change substantially. This study did not find that the risk pattern of lung cancer, possibly associated with residential radon exposure, in Misasa Town differed from patterns observed in other countries.
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