1
|
Kammerer S, Schuelke C, Berkemeyer S, Velasco A, Heindel W, Koehler M, Buerke B. The role of multislice computed tomography (MSCT) angiography in the diagnosis and therapy of non-occlusive mesenteric ischemia (NOMI): Could MSCT replace DSA in diagnosis? PLoS One 2018; 13:e0193698. [PMID: 29494649 PMCID: PMC5832260 DOI: 10.1371/journal.pone.0193698] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 02/18/2018] [Indexed: 12/24/2022] Open
Abstract
Objectives Evaluation of multislice-CT (MSCT) during diagnosis and therapeutic decision-making in patients with suspected non-occlusive mesenteric ischemia (NOMI). Methods Retrospective, institutional review board-approved study of 30 patients (20 men, 10 women, mean age 64.6±14.2 years, range 24–87 years) undergoing biphasic abdominal MSCT followed by digital subtraction angiography (DSA) due to suspected NOMI. MSCT and DSA were qualitatively and quantitatively evaluated independently by two radiologists with respect to the possible diagnosis of NOMI. MSCT analysis included quantitative measurements, qualitative evaluation of contrast enhancement and assessment of secondary findings (bowel wall thickening, hypo-enhancement, intestinal pneumatosis). MSCT diagnosis and secondary findings were compared against DSA diagnosis. Results NOMI was diagnosed in a total of n = 28 patients. No differences were found when comparing the R1-rated MSCT diagnosis (p = 0.09) to the “gold standard”, while MSCT diagnosis was slightly inferior with R2 (p = 0.02). With R1, vessel-associated parameters revealed the best correlation, i.e. qualitative vessel width (r = -0.39;p = 0.03) and vessel contrast (r = 0.45;p = 0.01). Moderate correlations were found for quantitative vessel diameters in the middle segments (r = -0.48,p = 0.01), increasing to almost high correlations in the distal (r = -0.66;p<0.00001) superior mesenteric artery (SMA) segments. No significant correlation was apparent from secondary findings. Conclusions MSCT is an appropriate non-invasive method for diagnosing NOMI and leads to adequate and immediate therapeutic stratification.
Collapse
Affiliation(s)
- Sara Kammerer
- Department of Clinical Radiology, University Hospital Muenster, Muenster, Germany
| | - Christoph Schuelke
- Department of Clinical Radiology, University Hospital Muenster, Muenster, Germany
| | - Shoma Berkemeyer
- Reference Center for Mammography, University Hospital Muenster, Muenster Germany
| | - Aglae Velasco
- Department of Clinical Radiology, University Hospital Muenster, Muenster, Germany
| | - Walter Heindel
- Department of Clinical Radiology, University Hospital Muenster, Muenster, Germany
| | - Michael Koehler
- Department of Clinical Radiology, University Hospital Muenster, Muenster, Germany
| | - Boris Buerke
- Department of Clinical Radiology, University Hospital Muenster, Muenster, Germany
- * E-mail:
| |
Collapse
|
2
|
Kammerer S, Höink AJ, Wessling J, Heinzow H, Koch R, Schuelke C, Heindel W, Buerke B. Abdominal and pelvic CT: is positive enteric contrast still necessary? Results of a retrospective observational study. Eur Radiol 2014; 25:669-78. [PMID: 25316055 DOI: 10.1007/s00330-014-3446-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 08/05/2014] [Accepted: 09/16/2014] [Indexed: 11/24/2022]
Abstract
PURPOSE Evaluation of diagnostic accuracy of abdominal CT depending on the type of enteric contrast agent. METHODS AND MATERIALS Multislice CTs of 2,008 patients with different types of oral preparation (positive with barium, n = 576; neutral with water, n = 716; and no enteric contrast, n = 716) were retrospectively evaluated by two radiologists including delineation of intestinal segments and influence on diagnosis and diagnostic reliability exerted by the enteric contrast, using a three-point scale. Furthermore, diagnostic reliability of the delineation of selected enteric pathologies was noted. CT data were assigned into groups: oncology, inflammation, vascular, pathology, trauma and gastrointestinal pathology. RESULTS Delineation of the bowel was clearly practicable across all segments irrespective of the type of enteric contrast, though a slight impairment was observed without enteric contrast. Although delineation of intestinal pathologies was mostly classified "clearly delimitable" more difficulties occurred without oral contrast (neutral/positive/no contrast, 0.8 %/3.8 %/6.5 %). Compared to examinations without enteric contrast, there was a significant improvement in diagnosis that was even increased regarding the reader's diagnostic reliability. Positive opacification impaired detection of mucosal enhancement or intestinal bleeding. CONCLUSION Water can replace positive enteric contrast agents in abdominal CTs. However, selected clinical questions require individual enteric contrast preparations. Pathology detection is noticeably impaired without any enteric contrast.
Collapse
Affiliation(s)
- S Kammerer
- Department of Clinical Radiology, University Hospital Münster, Münster, Germany,
| | | | | | | | | | | | | | | |
Collapse
|
3
|
Yamauchi-Kawaura C, Yamauchi M, Imai K, Ikeda M, Aoyama T. Image quality and age-specific dose estimation in head and chest CT examinations with organ-based tube-current modulation. RADIATION PROTECTION DOSIMETRY 2013; 157:193-205. [PMID: 23734058 DOI: 10.1093/rpd/nct137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The purpose of this study was to investigate the effects of an organ-based tube-current modulation (OBTCM) system on image quality and age-specific dose in head and chest CT examinations. Image noise, contrast-to-noise ratio (CNR) and image entropy were assessed using statistical and entropy analyses. Radiation doses for newborn, 6-y-old child and adult phantoms were measured with in-phantom dosimetry systems. The quality of CT images obtained with OBTCM was not different from that obtained without OBTCM. In head CT scans, the eye lens dose decreased by 20-33 % using OBTCM. In chest CT scans, breast dose decreased by 5-32 % using OBTCM. Posterior skin dose, however, increased by 11-20 % using OBTCM in head and chest CT scans. The reduction of effective dose using OBTCM was negligibly small. Detailed image quality and dose information provided in this study can be effectively used for OBTCM application.
Collapse
Affiliation(s)
- C Yamauchi-Kawaura
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
| | | | | | | | | |
Collapse
|
4
|
Liao Y, Lai N, Tyan Y, Chuang K, Tsai H. Automatic tube current modulation for volume scan in a 320-detector row CT scanner. RADIAT MEAS 2013. [DOI: 10.1016/j.radmeas.2013.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
5
|
Asli IN, Shahoseini R, Azizmohammadi Z, Javadi H, Assadi M. The utility and prognostic value of dipyridamole technetium-99m sestamibi myocardial perfusion imaging SPECT in predicting perioperative cardiac events following non-cardiac surgery. Perfusion 2013; 28:333-9. [PMID: 23482483 DOI: 10.1177/0267659113481398] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE A perioperative cardiac events is one of the most important medical concerns for both surgeons and patients. The purpose of the current study was to determine the prognostic value of myocardial perfusion imaging (MPI), using dipyridamole 99m Tc-MIBI, for the prediction of perioperative cardiac events. MATERIALS AND METHODS This study included 253 patients who were candidates for non-cardiac elective surgery and underwent scanning with dipyridamole 99m Tc-MIBI. Based on normal or abnormal MPI, patients were divided into two groups and all preoperative cardiac events were recorded. Risk factors, including diabetes mellitus, dyslipidemia, hypertension, smoking and age ≥70 years, were compared between patients with normal and abnormal MPI and, also, in patients with or without cardiac events. RESULTS There were 197 patients with normal and 56 patients with abnormal MPI. In total, 14 patients had perioperative cardiac events, which included myocardial infarction (MI), hypotension, arrhythmia and death; of the 14 patients with perioperative cardiac events, 12 had abnormal and two had normal MPI. There were statistically meaningful differences between the two groups (p<0.001). Based on these findings, we determined that MPI had a sensitivity of 85.7%, a specificity of 81.6%, an accuracy of 81.8%, a positive predictive value of 21.4 % and a negative predictive value of 98.9%. CONCLUSION The incidence of perioperative cardiac events is higher in patients with abnormal MPI. Dipyridamole 99m Tc-MIBI myocardial perfusion imaging can accurately detect the preoperative cardiac risk of patients undergoing major non-cardiac surgery. Based on these findings, the occurrence of perioperative cardiac events in patients with abnormal MPI should be considered, especially in the older age population (age ≥70).
Collapse
Affiliation(s)
- I N Asli
- Department of Nuclear Medicine, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | | | | | | |
Collapse
|
6
|
de Broucker T, Pontana F, Santangelo T, Faivre JB, Tacelli N, Delannoy-Deken V, Duhamel A, Remy J, Rémy-Jardin M. Single- and dual-source chest CT protocols: Levels of radiation dose in routine clinical practice. Diagn Interv Imaging 2012; 93:852-8. [DOI: 10.1016/j.diii.2012.07.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
7
|
Application of intraoperative computed tomography with or without navigation system in surgical correction of spinal deformity: a preliminary result of 59 consecutive human cases. Spine (Phila Pa 1976) 2012; 37:891-900. [PMID: 22024897 DOI: 10.1097/brs.0b013e31823aff81] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A retrospective analysis of patients undergoing spinal deformity correction surgery by the assistance of intraoperative computed tomography (iCT) with or without navigation system. OBJECTIVE To share our preliminary experience and analysis of the iCT navigation system applied to spinal deformity surgery. SUMMARY OF BACKGROUND DATA The iCT navigation system has been shown to improve accuracy and safety in posterior instrumentation. It not only decreased the operation time but also prevented excessive radiation exposure to the medical staff. To date, there are only few reports about the application of the iCT navigation system in spinal deformity surgery. METHODS From April 2009 to September 2010, 59 patients who had a diagnosis of scoliosis, kyphosis, or scoliokyphosis and underwent iCT-assisted surgical correction were included. Without randomization, 28 patients were operated with the iCT-navigation system, and the other 31 patients were operated with standard procedure under iCT assistance. The detailed procedures, preoperative and intraoperative images were illustrated. The accuracy of screw placement, time for screw insertion, postoperative correction rate, and iCT scanning data were analyzed. RESULTS There were significant differences between 2 groups in (1) the preoperative Cobb angle (76.2° and 62.6° in the navigation and non-navigation groups), (2) the accuracy and the revision rate of thoracic pedicle screws and total pedicle screws, and (3) the average screw insertion time. The breach rate and the revision rate of thoracic pedicle screws and total pedicle screws were significantly lower and the average screw insertion time was significantly lesser in the navigation group than in the non-navigation group. There were no statistically significant difference in (1) the breach rate and the revision rate of lumbar pedicle screws, (2) the mean iCT scanning time and time-out, (3) the mean number of fusion segments, (4) the mean number of iCT scans, and (5) the postoperative correction rate. Complications were encountered in 2 patients in the non-navigation group but none in the navigation group. There was no reoperation due to implant malposition in both groups. CONCLUSION The iCT navigation system provides desirable accuracy of posterior spinal instrumentation for patients during surgical correction of spinal deformity without radiation exposure to the medical staff, especially in thoracic spine instrumentation. Meanwhile, the iCT in itself is an effective means of assessing complex instrumentation of the spinal deformity.
Collapse
|
8
|
Christiaens L, Duchat F, Boudiaf M, Tasu JP, Fargeaudou Y, Ledref O, Soyer P, Sirol M. Impact of 64-slice coronary CT on the management of patients presenting with acute chest pain: results of a prospective two-centre study. Eur Radiol 2011; 22:1050-8. [DOI: 10.1007/s00330-011-2354-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 11/09/2011] [Accepted: 11/12/2011] [Indexed: 01/05/2023]
|
9
|
|
10
|
Sequential Versus Volumetric Computed Tomography in the Follow-up of Chronic Bronchopulmonary Diseases. J Thorac Imaging 2011; 26:190-5. [DOI: 10.1097/rti.0b013e3181f3a30e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
11
|
He W, Huda W, Magill D, Tavrides E, Yao H. X-ray tube current modulation and patient doses in chest CT. RADIATION PROTECTION DOSIMETRY 2011; 143:81-87. [PMID: 21068019 DOI: 10.1093/rpd/ncq291] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The aim of the study was to investigate how patient effective doses vary as a function of X-ray tube projection angle, as well as the patient long axis, and quantify how X-ray tube current modulation affects patient doses in chest CT examinations. Chest examinations were simulated for a gantry CT scanner geometry with projections acquired for a beam width of 4 cm. PCXMC 2.0.1 was used to calculate patient effective doses at 15° intervals around the patient's isocentre, and at nine locations along the patient long axis. Idealised tube current modulation schemes were modelled as a function of the X-ray tube angle and the patient long axis. Tube current modulations were characterised by the modulation amplitude R, which was allowed to vary between 1.5 and 5. Effective dose maxima occur for anteroposterior projections at the location of the (radiosensitive) breasts. The maximum to minimum ratio of effective doses as a function of the patient long axis was 4.9, and as a function of the X-ray tube angle was 2.1. Doubling the value of R reduces effective doses from longitudinal modulation alone by ∼4% and from angular modulation alone by ∼2%. In chest CT, tube current modulation schemes currently have longitudinal R values of ∼2.2, and angular R values that range between 1.5 and 3.4. Current X-ray tube current modulation schemes are expected to reduce patient effective doses in chest CT examinations by ∼10%, with longitudinal modulation accounting for two-thirds and angular modulation for the remaining one-third.
Collapse
Affiliation(s)
- Wenjun He
- Clemson-MUSC Bioengineering program, Department of Bioengineering, Clemson University, Charleston, SC 29425, USA.
| | | | | | | | | |
Collapse
|
12
|
|
13
|
Seneviratne SK, Truong QA, Bamberg F, Rogers IS, Shapiro MD, Schlett CL, Chae CU, Cury R, Abbara S, Brady TJ, Nagurney JT, Hoffmann U. Incremental diagnostic value of regional left ventricular function over coronary assessment by cardiac computed tomography for the detection of acute coronary syndrome in patients with acute chest pain: from the ROMICAT trial. Circ Cardiovasc Imaging 2010; 3:375-83. [PMID: 20484542 DOI: 10.1161/circimaging.109.892638] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The incremental value of regional left ventricular function (LVF) over coronary assessment to detect acute coronary syndrome (ACS) is uncertain. METHODS AND RESULTS We analyzed 356 patients (mean age, 53+/-12 years; 62% men) with acute chest pain and inconclusive initial emergency department evaluation. Patients underwent 64-slice contrast-enhanced cardiac computed tomography before hospital admission. Caregivers and patients remained blinded to the results. Regional LVF and presence of coronary atherosclerotic plaque and significant stenosis (>50%) were separately assessed by 2 independent readers. Incremental value of regional LVF to predict ACS was determined in the entire cohort and in subgroups of patients with nonobstructive coronary artery disease, inconclusive assessment for stenosis (defined as inability to exclude significant stenosis due to calcium or motion), and significant stenosis. During their index hospitalization, 31 patients were ultimately diagnosed with ACS (8 myocardial infarction, 22 unstable angina), of which 74% (23 patients) had regional LV dysfunction. Adding regional LVF resulted in a 10% increase in sensitivity to detect ACS by cardiac computed tomography (87%; 95% confidence interval, 70% to 96%) and significantly improved the overall accuracy (c-statistic: 0.88 versus 0.94 and 0.79 versus 0.88, for extent of plaque and presence of stenosis, respectively; both P<0.03). The diagnostic accuracy of regional LVF for detection of ACS has 89% sensitivity and 86% specificity in patients with significant stenosis (n=33) and 60% sensitivity and 86% specificity in patients with inconclusive coronary computed tomographic angiography (n=33). CONCLUSIONS Regional LVF assessment at rest improves diagnostic accuracy for ACS in patients with acute chest pain, especially in those with coronary artery disease and thus may be helpful to guide further management in patients at intermediate risk for ACS.
Collapse
Affiliation(s)
- Sujith K Seneviratne
- Cardiac MR PET CT Program, Department of Radiology and Division of Cardiology, Massachusetts General Hospital and Harvard Medical School, 165 Charles River Plaza, Boston, MA 02114, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Kekelidze M, Dwarkasing RS, Dijkshoorn ML, Sikorska K, Verhagen PCMS, Krestin GP. Kidney and urinary tract imaging: triple-bolus multidetector CT urography as a one-stop shop--protocol design, opacification, and image quality analysis. Radiology 2010; 255:508-16. [PMID: 20160002 DOI: 10.1148/radiol.09082074] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE To retrospectively evaluate renal, vascular, and urinary tract visualization following a single postcontrast multidetector computed tomographic (CT) urographic sequence performed with three limited-volume bolus injections. MATERIALS AND METHODS The institutional review board approved this retrospective study. Patient informed consent was waived. Triple-bolus multidetector CT urography was performed in 110 patients. Triple-bolus protocol consisted of 30 mL of contrast material at 2 mL/sec at 0 seconds, 50 mL at 1.5 mL/sec at 435 seconds, 65 mL at 3 mL/sec at 488 seconds, with total abdominal scanning time of 510 seconds. Two independent readers rated urinary tract opacification and qualitatively and quantitatively assessed renal parenchymal and vascular contrast enhancement. Upper urinary tract (UUT) distention was measured by one reader. Interobserver agreement was assessed by using kappa statistics. RESULTS Complete opacification of the intrarenal collecting system and proximal ureter was achieved in 91% (184 of 202) (kappa = 0.62) and 82% (166 of 202) (kappa = 0.94) of segments, respectively. The distal ureter was not opacified in 21% of the cases (kappa = 0.92), and the bladder was not opacified in 20% of the cases. Mean distention was higher for proximal (3.9 mm) than for distal (3.7 mm) segments. Image quality of renal parenchymal enhancement was excellent in 76% of cases. Arteries showed better contrast enhancement than veins (excellent rating in 89% vs 59% of the cases). Radiation dose calculated for triple-bolus acquisition was 9.8 mSv. CONCLUSION Triple-bolus multidetector CT urography is a dose-efficient protocol acquiring corticomedullary-nephrographic-excretory and vascular enhancement phases in a single acquisition and provides sufficient opacification and distention of the UUT. Simultaneously, adequate image quality of renal parenchyma and vascular anatomy is achieved.
Collapse
Affiliation(s)
- Maka Kekelidze
- Department of Radiology, Erasmus Medical Center Rotterdam, 's-Gravendijkwal 230, 3015 CE Rotterdam, the Netherlands.
| | | | | | | | | | | |
Collapse
|
15
|
Tacelli N, Remy-Jardin M, Flohr T, Faivre JB, Delannoy V, Duhamel A, Remy J. Dual-source chest CT angiography with high temporal resolution and high pitch modes: evaluation of image quality in 140 patients. Eur Radiol 2009; 20:1188-96. [DOI: 10.1007/s00330-009-1638-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Revised: 08/25/2009] [Accepted: 09/01/2009] [Indexed: 10/20/2022]
|
16
|
Uhl E, Zausinger S, Morhard D, Heigl T, Scheder B, Rachinger W, Schichor C, Tonn JC. Intraoperative computed tomography with integrated navigation system in a multidisciplinary operating suite. Neurosurgery 2009; 64:231-9; discussion 239-40. [PMID: 19404103 DOI: 10.1227/01.neu.0000340785.51492.b5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE We report our preliminary experience in a prospective series of patients with regard to feasibility, work flow, and image quality using a multislice computed tomographic (CT) scanner combined with a frameless neuronavigation system (NNS). METHODS A sliding gantry 40-slice CT scanner was installed in a preexisting operating room. The scanner was connected to a frameless infrared-based NNS. Image data was transferred directly from the scanner into the navigation system. This allowed updating of the NNS during surgery by automated image registration based on the position of the gantry. Intraoperative CT angiography was possible. The patient was positioned on a radiolucent operating table that fits within the bore of the gantry. During image acquisition, the gantry moved over the patient. This table allowed all positions and movements like any normal operating table without compromising the positioning of the patient. For cranial surgery, a carbon-made radiolucent head clamp was fixed to the table. RESULTS Experience with the first 230 patients confirms the feasibility of intraoperative CT scanning (136 patients with intracranial pathology, 94 patients with spinal lesions). After a specific work flow, interruption of surgery for intraoperative scanning can be limited to 10 to 15 minutes in cranial surgery and to 9 minutes in spinal surgery. Intraoperative imaging changed the course of surgery in 16 of the 230 cases either because control CT scans showed suboptimal screw position (17 of 307 screws, with 9 in 7 patients requiring correction) or that tumor resection was insufficient (9 cases). Intraoperative CT angiography has been performed in 7 cases so far with good image quality to determine residual flow in an aneurysm. Image quality was excellent in spinal and cranial base surgery. CONCLUSION The system can be installed in a preexisting operating environment without the need for special surgical instruments. It increases the safety of the patient and the surgeon without necessitating a change in the existing surgical protocol and work flow. Imaging and updating of the NNS can be performed at any time during surgery with very limited time and modification of the surgical setup. Multidisciplinary use increases utilization of the system and thus improves the cost-efficiency relationship.
Collapse
Affiliation(s)
- Eberhard Uhl
- Department of Neurosurgery, Klinikum Grosshadern, University of Munich, Munich, Germany. eberhard.uhl@ lkh- klu.at
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Quantitative assessment of image noise and streak artifact on CT image: Comparison of z-axis automatic tube current modulation technique with fixed tube current technique. Comput Med Imaging Graph 2009; 33:353-8. [DOI: 10.1016/j.compmedimag.2009.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2008] [Revised: 01/25/2009] [Accepted: 02/23/2009] [Indexed: 11/20/2022]
|
18
|
Coronary computed tomography angiography for early triage of patients with acute chest pain: the ROMICAT (Rule Out Myocardial Infarction using Computer Assisted Tomography) trial. J Am Coll Cardiol 2009; 53:1642-50. [PMID: 19406338 DOI: 10.1016/j.jacc.2009.01.052] [Citation(s) in RCA: 401] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 12/19/2008] [Accepted: 01/12/2009] [Indexed: 11/22/2022]
Abstract
OBJECTIVES This study was designed to determine the usefulness of coronary computed tomography angiography (CTA) in patients with acute chest pain. BACKGROUND Triage of chest pain patients in the emergency department remains challenging. METHODS We used an observational cohort study in chest pain patients with normal initial troponin and nonischemic electrocardiogram. A 64-slice coronary CTA was performed before admission to detect coronary plaque and stenosis (>50% luminal narrowing). Results were not disclosed. End points were acute coronary syndrome (ACS) during index hospitalization and major adverse cardiac events during 6-month follow-up. RESULTS Among 368 patients (mean age 53 +/- 12 years, 61% men), 31 had ACS (8%). By coronary CTA, 50% of these patients were free of coronary artery disease (CAD), 31% had nonobstructive disease, and 19% had inconclusive or positive computed tomography for significant stenosis. Sensitivity and negative predictive value for ACS were 100% (n = 183 of 368; 95% confidence interval [CI]: 98% to 100%) and 100% (95% CI: 89% to 100%), respectively, with the absence of CAD and 77% (95% CI: 59% to 90%) and 98% (n = 300 of 368, 95% CI: 95% to 99%), respectively, with significant stenosis by coronary CTA. Specificity of presence of plaque and stenosis for ACS were 54% (95% CI: 49% to 60%) and 87% (95% CI: 83% to 90%), respectively. Only 1 ACS occurred in the absence of calcified plaque. Both the extent of coronary plaque and presence of stenosis predicted ACS independently and incrementally to Thrombolysis In Myocardial Infarction risk score (area under curve: 0.88, 0.82, vs. 0.63, respectively; all p < 0.0001). CONCLUSIONS Fifty percent of patients with acute chest pain and low to intermediate likelihood of ACS were free of CAD by computed tomography and had no ACS. Given the large number of such patients, early coronary CTA may significantly improve patient management in the emergency department.
Collapse
|
19
|
Radiation reduction with prospective ECG-triggering acquisition using 64-multidetector computed tomographic angiography. Int J Cardiovasc Imaging 2008; 25:405-16. [DOI: 10.1007/s10554-008-9396-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
|
20
|
Bhalla S, Javidan-Nejad C, Bierhals AJ, Woodard PK, Gutierrez FR. CT in the evaluation of congenital heart disease in children, adolescents, and young adults. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2008; 10:425-32. [DOI: 10.1007/s11936-008-0034-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
21
|
Papadakis AE, Perisinakis K, Damilakis J. Automatic exposure control in pediatric and adult multidetector CT examinations: A phantom study on dose reduction and image quality. Med Phys 2008; 35:4567-76. [DOI: 10.1118/1.2977535] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
|
22
|
Application of Automatic Vertical Positioning Software to Reduce Radiation Exposure in Multidetector Row Computed Tomography of the Chest. Invest Radiol 2008; 43:447-52. [DOI: 10.1097/rli.0b013e318169005e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
23
|
Butler J, Mooyaart EA, Dannemann N, Bamberg F, Shapiro MD, Ferencik M, Brady TJ, Hoffmann U. Relation of the metabolic syndrome to quantity of coronary atherosclerotic plaque. Am J Cardiol 2008; 101:1127-30. [PMID: 18394445 DOI: 10.1016/j.amjcard.2007.12.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2007] [Revised: 12/09/2007] [Accepted: 12/09/2007] [Indexed: 01/22/2023]
Abstract
Although metabolic syndrome (MS) is associated with adverse cardiovascular outcomes, its association with the presence and extent of coronary atherosclerotic plaques is not well described. To assess this relation, multidetector computed tomography-based patterns of coronary plaque were assessed in 77 patients enrolled in the ROMICAT study (age 54 +/- 12 years; 79% Caucasians, and 36% women) and compared between those who did (n = 35; 45%) and did not (n = 42; 55%) have MS. The presence of any, calcified, and noncalcified plaque was significantly higher in patients with than without MS (91%, 74%, and 77% vs 46%, 45%, and 40% segments with plaque, respectively; all p <0.01). The overall number of segments with plaques was also higher in patients with MS (5.8 +/- 3.7 vs 2.1 +/- 3.3; p <0.001). MS was independently associated with both the presence and extent of overall plaques after adjusting for the Framingham risk score (odds ratio 6.7, 95% confidence interval 1.6 to 28.8, p <0.01 for presence, beta coefficient = 3.59 +/- 0.88 [SE], p = 0.009 for extent) and individual risk factors, including age, gender, smoking, body mass index, hypertension, diabetes, hyperlipidemia, and clinical coronary disease (odds ratio 8.4, 95% confidence interval 1.7 to 42.5, p = 0.008 for presence, beta coefficient = 2.35 +/- 0.86 [SE], p = 0.007 for extent). Similarly, MS was independently associated with calcified and noncalcified plaques individually. In conclusion, MS was independently associated with the presence and extent of both calcified and noncalcified coronary atherosclerotic plaques detected using multidetector computed tomography. These data may explain the higher cardiovascular risk in these patients and may lay the foundation for studies to determine whether such information may improve risk stratification.
Collapse
|
24
|
Reduction of Radiation Dose Estimates in Cardiac 64-Slice CT Angiography in Patients After Coronary Artery Bypass Graft Surgery. Invest Radiol 2008; 43:253-60. [DOI: 10.1097/rli.0b013e318160b3a3] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
25
|
Laissy JP, Bazeli R, Serfaty JM. Tomodensitométrie cardiaque : indications et perspectives. Presse Med 2008; 37:724-31. [DOI: 10.1016/j.lpm.2007.07.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Accepted: 07/02/2007] [Indexed: 10/22/2022] Open
|
26
|
Moloo J, Shapiro MD, Abbara S. Cardiac Computed Tomography: Technique and Optimization of Protocols. Semin Roentgenol 2008; 43:90-9. [DOI: 10.1053/j.ro.2008.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
27
|
Lee IS, Kim HJ, Choi BK, Jeong YJ, Lee TH, Moon TY, Won Kang D. A Pragmatic Protocol for Reduction in the Metal Artifact and Radiation Dose in Multislice Computed Tomography of the Spine. J Comput Assist Tomogr 2007; 31:635-41. [PMID: 17882046 DOI: 10.1097/01.rct.0000250117.18080.d8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To assess the correlation between the metal artifact degree and the tube voltage (in peak kilovolts; kVp) and tube current (in milliamperes; mA) in multidetector row computed tomography (MDCT) and evaluate the proper protocols for reduction in the metal artifact and the radiation dose. METHODS We performed MDCT examinations for 13 cadavers operated for transpedicular screw insertion from C3 to C7, bilaterally. We used 80, 100, and 120 kVp in all cadavers. For the mA, we arbitrarily applied 100, 150, and 200 in 6 cadavers (experiment 1); 140, 180, and 220 in 4 (experiment 2), and randomly used mAs between 60 and 220 in 3 (experiment 3). The lengths of the artifacts emanating from the anterior and posterior tips of the screw were used for the degree of artifact. RESULTS In experiment 1, the mA did not significantly affect the metal artifacts (P > 0.05); but the kVp did (P < 0.05). In experiment 2, the mA and kVp did not significantly affect the metal artifact degree (P > 0.05). In experiment 3, the mA did not affect the metal artifacts, but the kVp caused changes in metal artifact degrees (simple quantitative analysis). CONCLUSIONS The proper parameters for the simultaneous reduction in the artifact and radiation dose are suggested to be tube voltages from 100 to 120 kVp and tube currents lower than the generally used values of 200 to 220 mA.
Collapse
Affiliation(s)
- In Sook Lee
- Department of Radiology, College of Medicine, Pusan National University, Busan, Korea
| | | | | | | | | | | | | |
Collapse
|
28
|
Papadakis AE, Perisinakis K, Damilakis J. Angular on-line tube current modulation in multidetector CT examinations of children and adults: The influence of different scanning parameters on dose reduction. Med Phys 2007; 34:2864-74. [PMID: 17821994 DOI: 10.1118/1.2747048] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The purpose of this study was to assess the potential of angular on-line tube current modulation on dose reduction in pediatric and adult patients undergoing multidetector computed tomography (MDCT) examinations. Five physical anthropomorphic phantoms that simulate the average individual as neonate, 1-year-old, 5-year-old, 10-year-old, and adult were employed in the current study. Phantoms were scanned with the use of on-line tube current modulation (TCM). Percent dose reduction (%DR) factors achieved by applying TCM, were determined for standard protocols used for head and neck, shoulder, thorax, thorax and abdomen, abdomen, abdomen and pelvis, pelvis, and whole body examinations. A preliminary study on the application of TCM in MDCT examinations of adult patients was performed to validate the results obtained in anthropomorphic phantoms. Dose reduction was estimated as the percentage difference of the modulated milliamperes for each scan and the preset milliamperes prescribed by the scan protocol. The dose reduction in children was found to be much lower than the corresponding reduction achieved for adults. For helical scans the %DR factors, ranged between 1.6% and 7.4% for the neonate, 2.9% and 8.7% for the 1-year old, 2% and 6% for the 5-year-old, 5% and 10.9% for the 10-year-old, and 10.4% and 20.7% for the adult individual. For sequential scans the corresponding %DR factors ranged between 1.3% and 6.7%, 4.5% and 11%, 4.2% and 6.6%, 6.4% and 12.3%, and 8.9% and 23.3%, respectively. Broader beam collimations are associated with decreased %DR factors, when other scanning parameters are held constant. TCM did not impair image noise. In adult patients, the %DR values were found to be in good agreement with the corresponding results obtained in the anthropomorphic adult phantom. In conclusion, on-line TCM may be considered as a valuable tool for reducing dose in routine CT examinations of pediatric and adult patients. However, the dose reduction achieved with TCM in neonates and young children was found to be lower than that obtained for adults. Therefore, on-line TCM should work as an additional means to reduce dose and should not replace other conventional means of reducing dose, especially in neonates and young children.
Collapse
Affiliation(s)
- Antonios E Papadakis
- Department of Medical Physics, Faculty of Medicine, University of Crete, PO Box 2208, Iraklion 71003, Crete, Greece.
| | | | | |
Collapse
|
29
|
Hamer OW, Schlottmann K, Sirlin CB, Feuerbach S. Technology Insight: advances in liver imaging. ACTA ACUST UNITED AC 2007; 4:215-28. [PMID: 17404589 DOI: 10.1038/ncpgasthep0766] [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] [Received: 08/07/2006] [Accepted: 01/26/2007] [Indexed: 12/23/2022]
Abstract
The role of diagnostic imaging in the assessment of liver disease continues to gain in importance. The classic techniques used for liver imaging are ultrasonography, CT and MRI. In the past decade, there have been significant advances in all three techniques. In this article, we discuss the advances in ultrasonography, CT and MRI that have improved assessment of focal and diffuse liver disease, including the development of hardware, software, processing algorithms and procedural innovations.
Collapse
Affiliation(s)
- Okka W Hamer
- University Hospital of Regensburg, Department of Radiology, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
| | | | | | | |
Collapse
|
30
|
Butler J. The Emerging Role of Multi-Detector Computed Tomography in Heart Failure. J Card Fail 2007; 13:215-26. [PMID: 17448420 DOI: 10.1016/j.cardfail.2006.11.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 11/18/2006] [Accepted: 11/21/2006] [Indexed: 11/26/2022]
Abstract
BACKGROUND Recent advances in cardiac multi-detector computed tomography (MDCT) technology now permits entire coronary tree evaluation in a single breath hold with submillimeter slice collimation and improved temporal resolution. METHODS AND RESULTS Besides excellent correlation with invasive angiogram for the detection of significant coronary occlusion, MDCT also provides reliable and reproducible data regarding various other cardiac anatomic and functional parameters that are pertinent to heart failure patients. These include left ventricular measurement (eg, ejection fraction, regional wall motion, dimensions, volumes), pulmonary vein anatomy and drainage, right ventricular function, and cardiac venous system, among many others. However, there are radiogenic and nonradiogenic risks associated with MDCT that should be considered before scanning the patients. CONCLUSIONS This review summarizes the existing literature of the various cardiac MDCT applications pertinent to heart failure patients.
Collapse
|
31
|
Deetjen A, Möllmann S, Conradi G, Rolf A, Schmermund A, Hamm CW, Dill T. Use of automatic exposure control in multislice computed tomography of the coronaries: comparison of 16-slice and 64-slice scanner data with conventional coronary angiography. Heart 2007; 93:1040-3. [PMID: 17395667 PMCID: PMC1955015 DOI: 10.1136/hrt.2006.103838] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE To evaluate the radiation-dose-reduction potential of automatic exposure control (AEC) in 16-slice and 64-slice multislice computed tomography (MSCT) of the coronary arteries (computed tomography angiography, CTA) in patients. The rapid growth in MSCT CTA emphasises the necessity of adjusting technique factors to reduce radiation dose exposure. DESIGN A retrospective data analysis was performed for 154 patients who had undergone MSCT CTA. Group 1 (n = 56) had undergone 16-slice MSCT without AEC, and group 2 (n = 51), with AEC. In group 1, invasive coronary angiography (ICA) had been performed in addition. Group 3 (n = 47) had been examined using a 64-slice scanner (with AEC, without ECG-triggered tube current modulation). RESULTS In group 1, the mean (SD) effective dose (ED) for MSCT CTA was 9.76 (1.84) mSv and for ICA it was 2.6 (1.27) mSv. In group 2, the mean ED for MSCT CTA was 5.83 (1.73) mSv, which signifies a 42.8% dose reduction for CTA by the use of AEC. In comparison to ICA, MSCT CTA without AEC shows a 3.8-fold increase in radiation dose, and the radiation dose of CTA with AEC was increased by a factor of 1.9. In group 3, the mean ED for MSCT CTA was 13.58 (2.80) mSV. CONCLUSIONS This is the first study to show the significant dose-reduction potential (42.8%) of AEC in MSCT CTA in patients. This relatively new technique can be used to optimise the radiation dose levels in MSCT CTA.
Collapse
Affiliation(s)
- Anja Deetjen
- Department of Cardiology/Cardiovascular Imaging, Kerckhoff Heart Center, Bad Nauheim, Germany.
| | | | | | | | | | | | | |
Collapse
|
32
|
Paterson A, Frush DP. Dose reduction in paediatric MDCT: general principles. Clin Radiol 2007; 62:507-17. [PMID: 17467387 DOI: 10.1016/j.crad.2006.12.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 12/11/2006] [Accepted: 12/18/2006] [Indexed: 01/07/2023]
Abstract
The number of multi-detector array computed tomography (MDCT) examinations performed per annum continues to increase in both the adult and paediatric populations. Estimates from 2003 suggested that CT contributed 17% of a radiology department's workload, yet was responsible for up to 75% of the collective population dose from medical radiation. The effective doses for some CT examinations today overlap with those argued to have an increased risk of cancer. This is especially pertinent for paediatric CT, as children are more radiosensitive than adults (and girls more radiosensitive than boys). In addition, children have a longer life ahead of them, in which radiation induced cancers may become manifest. Radiologists must be aware of these facts and practise the ALARA (as low as is reasonably achievable) principle, when it comes to deciding CT protocols and parameters.
Collapse
Affiliation(s)
- A Paterson
- Radiology Department, Royal Belfast Hospital for Sick Children, Belfast, UK.
| | | |
Collapse
|
33
|
Hoffmann U, Pena AJ, Moselewski F, Ferencik M, Abbara S, Cury RC, Chae CU, Nagurney JT. MDCT in Early Triage of Patients with Acute Chest Pain. AJR Am J Roentgenol 2006; 187:1240-7. [PMID: 17056911 DOI: 10.2214/ajr.05.2240] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Current risk stratification of patients with acute chest pain but normal initial cardiac enzymes and nondiagnostic ECG is inefficient. We sought to determine whether contrast-enhanced MDCT-based detection of stenosis is feasible and improves early and accurate triage of patients with acute chest pain. SUBJECTS AND METHODS We studied 40 patients (53% men; mean age, 57 +/- 13 years) with chest pain who were awaiting hospital admission to rule out an acute coronary syndrome (ACS) despite the absence of diagnostic ECG changes and normal cardiac enzymes on emergency department presentation. Patients underwent contrast-enhanced MDCT before hospital admission. Afterward, patients received standard clinical care. All physicians involved in the patients' care were blinded to the results of MDCT. An expert panel established the presence or absence of ACS based on American Heart Association (AHA) guidelines. The MDCT images were evaluated for the presence of significant coronary artery stenosis (diameter reduction > 50%) and were used to make a triage decision. RESULTS All five patients (12.5%) with ACS (one with non-ST elevation myocardial infarction, four with unstable angina pectoris) had at least one significant coronary stenosis on MDCT (sensitivity, 100% [95% CI, 49-100%)]. ACS was ruled out in 35 patients (87.5%). Significant coronary stenosis was excluded in 26 of the 35 patients without ACS by MDCT (specificity, 74% [CI, 75-88%]), potentially saving 70% of unnecessary hospital admissions. CONCLUSION MDCT-based detection of significant coronary stenoses has tremendous potential to decrease the number of unnecessary hospital admissions, without reducing appropriate admission rates, in patients with chest pain who have nondiagnostic ECG results and normal cardiac enzymes. These results are likely to further improve with advances in MDCT technology.
Collapse
Affiliation(s)
- Udo Hoffmann
- Department of Radiology, Massachusetts General Hospital Cardiac MR CT PET Program and Harvard Medical School, 100 CPZ 400, Boston, MA 02114, USA.
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Heggie JCP, Kay JK, Lee WK. Importance in optimization of multi-slice computed tomography scan protocols. ACTA ACUST UNITED AC 2006; 50:278-85. [PMID: 16732832 DOI: 10.1111/j.1440-1673.2006.01579.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper reviews the reasons why multi-slice CT scanners may give patients higher dose than their single-slice predecessors and discusses the type of optimization of multi-slice scan protocols that may be undertaken to keep patient doses to acceptable levels without compromising image quality. It also provides estimates of patient effective dose values and dose length products for typical procedures and briefly discusses the implication that these dose values have for the induction of possible stochastic effects.
Collapse
Affiliation(s)
- J C P Heggie
- Department of Medical Engineering and Physics, St Vincent's Hospital Melbourne, Victoria, Australia.
| | | | | |
Collapse
|
35
|
Körner M, Krötz M, Kanz KG, Pfeifer KJ, Reiser M, Linsenmaier U. Development of an accelerated MSCT protocol (Triage MSCT) for mass casualty incidents: comparison to MSCT for single-trauma patients. Emerg Radiol 2006; 12:203-9. [PMID: 16733685 DOI: 10.1007/s10140-006-0485-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2005] [Accepted: 02/24/2006] [Indexed: 11/26/2022]
Abstract
During multiple casualty incidents (MCI) emergency radiology departments have to deal with a large number of patients with suspected severe trauma within a short period of time. The aim of this study was to develop a suitable accelerated multislice computed tomography (MSCT) protocol to increase patient throughput for this kind of emergency situation. We presumed a scenario of 15 patients being admitted to the trauma service with suspicion of severe injuries after a MCI over a period of 2 h. An accelerated Triage MSCT protocol was developed and evaluated for MSCT scanner productivity (patients per hour) and time (minutes) needed for a total MSCT body workup using an anthropomorphic phantom. In addition, time (minutes) for transfer and preparation was measured. These timeframes were compared to a control group consisting of 144 single patients with multiple trauma undergoing standard MSCT according to our trauma room protocol. All MSCT studies were conducted using a 4-detector row scanner. (1) For the study group (Triage MSCT), average time for patient transfer and preparation was 2.9 min (2.5-4.3 min), mean CT examination time was 2.1 min (1.7-2.4 min); image reconstruction took 4.0 min (3.3-4.3 min). Total time in scanner room was 8.9 min (7.7-11.3 min), resulting in a maximal productivity of 6.7 patients per hour. Image transfer to the digital picture archive and communication system archive was completed after an average 9.5 min (8.9-10.8 min). (2) For the control group (single casualty MSCT), the mean time for patient transfer and preparation was 20.4 min (9.0-39.2 min), mean examination time was 6.0 min (3.1-11.3 min). Times for image reconstructions were not recorded in the patient series. Mean total time in scanner room was 25.3 min (11.0-72.4 min), resulting in a patient throughput of 2.4 patients per hour. MSCT has potential to serve as a powerful tool in triage of multiple casualty patients. The introduction of a Triage MSCT scanning protocol resulted in an increase of patient throughput per hour by a factor of almost 3.
Collapse
Affiliation(s)
- M Körner
- Department of Clinical Radiology, Ludwig-Maximilians-University Hospital, Nussbaumstrasse 20, 80336 Munich, Germany.
| | | | | | | | | | | |
Collapse
|
36
|
d'Agostino AG, Remy-Jardin M, Khalil C, Delannoy-Deken V, Flohr T, Duhamel A, Remy J. Low-dose ECG-gated 64-slices helical CT angiography of the chest: evaluation of image quality in 105 patients. Eur Radiol 2006; 16:2137-46. [PMID: 16609862 DOI: 10.1007/s00330-006-0218-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 02/21/2006] [Accepted: 02/23/2006] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to evaluate image quality of low-dose electrocardiogram (ECG)-gated multislice helical computed tomography (CT) angiograms of the chest. One hundred and five consecutive patients with a regular sinus rhythm (72 men; 33 women) underwent ECG-gated CT angiographic examination of the chest without administration of beta blockers using the following parameters: (a) collimation 32 x 0.6 mm with z-flying focal spot for the acquisition of 64 overlapping 0.6-mm slices, rotation time 0.33 s, pitch 0.3; (b) 120 kV, 200 mAs; (c) use of two dose modulation systems, including adjustment of the mAs setting to the patient's size and anatomical shape and an ECG-controlled tube current. Subjective and objective image quality was evaluated by two radiologists in consensus on 3-mm-thick scans reconstructed at 55% of the response rate (RR) interval. The population and protocol characteristics included: (a) a mean [+/-standard deviation (SD)] body mass index (BMI) of 24.47 (+/-4.64); (b) a mean (+/-SD) heart rate of 72.04 (+/-15.76) bpm; (c) a mean (+/-SD) scanning time of 18.3 (+/-2.73) s; (d) a mean (+/-SD) dose-length product (DLP) value of 260.57 (+/-83.67) mGy/cm; (e) an estimated average effective dose of 4.95 (+/-1.59) mSv. Subjective noise was depicted in a total of nine examinations (8.5%), always rated as mild. Objective noise was assessed by measuring the standard deviation of pixel values in a homogeneous region of interest within the trachea and descending aorta; SD was 15.91 HU in the trachea and 22.16 HU in the descending aorta, with no significant difference in the mean value of the standard deviations between the four categories of BMI except for obese patients, who had a higher mean SD within the aorta. Interpolation artefacts were depicted in 22 patients, with a mean heart rate significantly lower than that of patients without interpolation artifacts, rated as mild in 11 patients and severe in 11 patients. The severity of interpolation artefacts was significantly linked to a low heart rate in affected patients. The overall image quality of CT scans was rated as diagnostic in 94 patients (89.5%) while 11 examinations (10.5%) were found to be partially nondiagnostic owing to the cyclic presence of severe interpolation artefacts, which can be compensated for by additional reconstructions at a different temporal window. In these cases, interpolation artefacts could have been avoided by reducing the pitch from 0.3 to 0.2 at the expense of increased patient dose. Low-dose ECG-gated CT angiograms of the chest can be obtained in routine clinical practice with 64-slice CT technology without altering the diagnostic value of CT scans.
Collapse
Affiliation(s)
- A G d'Agostino
- Department of Thoracic Imaging, Hospital Calmette, University Center of Lille, Boulevard Jules Leclerc, 59037, Lille Cedex, France
| | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
Cardiac multidetector CT (MDCT) has moved from purely anatomic imaging, to assessment of cardiac function. Significant advances since the advent of multidetector CT now make it feasible to assess not only the coronary arteries, but also ejection fraction, ventricular volumes, myocardial mass and the presence of wall-motion abnormalities. Advances include improvements in EKG-gating, including improvements in temporal resolution, as well as the addition of delayed contrast-enhanced methods. Anatomic imaging has improved as well, with thinner collimation and better reconstruction methods. Three-dimensional software programs now permit excellent surface rendered displays and multiplanar reconstructions suitable as surgical and procedural "road maps."
Collapse
Affiliation(s)
- Pamela K Woodard
- Cardiovascular Imaging Laboratory, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | | | | | | |
Collapse
|
38
|
Matsubara K, Koshida K, Suzuki M, Hayakawa M, Tsujii H, Yamamoto T. Evaluation of variations in absorbed dose and image noise according to patient forms in X-ray computed tomography. Nihon Hoshasen Gijutsu Gakkai Zasshi 2005; 61:1581-6. [PMID: 16395231 DOI: 10.6009/jjrt.kj00004022967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Excessive radiation exposure in pediatric computed tomography (CT) scanning has become a serious problem, and it is difficult to select scan parameters for the scanning of small patients such as children. We investigated differences in absorbed dose and standard deviation (SD) in Hounsfield unit (HU) caused by differences in the form of the subject using a body-type phantom with removable body parts. Using four X-ray CT scanners, measurements were made with values from 50 mAs to 300 mAs, with slices of 50 mAs, using scan protocols that were assumed to perform thorough examinations. The results showed that the mAs values and absorbed doses were almost proportional, and the absorbed doses in the phantom without body parts were about 1.1-2.2-fold higher than those of the phantom with body parts at the same points. The SD values obtained indicated that the absorbed doses in the phantom with body parts were 0.3-0.6 times those of the phantom without body parts when the mAs values used were adjusted so that both SD values were the same. The absorbed doses in various patient forms can be estimated from these results, and they will become critical data for the selection of appropriate scan protocols.
Collapse
Affiliation(s)
- Kosuke Matsubara
- Department of Radiological Technology, Kanazawa University Hospital
| | | | | | | | | | | |
Collapse
|
39
|
Abstract
BACKGROUND & AIMS Computed tomography colonography (CTC), particularly using noncathartic techniques, has the clear potential to increase compliance for colorectal cancer screening. Because the geometry for CTC is highly advantageous, it can be performed with lower radiation doses than almost any other CT examination. If CTC were to become a standard screening tool for the population age 50 years and older, the potential market in the United States would soon be over 100 million people. Therefore, it is pertinent to consider the radiation exposure and any potential radiation risk to the population from such a mass CTC screening program. METHODS Organ doses from CTC examinations can be estimated with standard techniques. These doses can be applied to organ- and dose-specific radiation cancer risk estimates to estimate the excess cancer risk resulting from the radiation from a paired (supine and prone) CTC examination. RESULTS The cancer risks associated with the radiation exposure from CTC are unlikely to be zero, but they are small. A best estimate for the absolute lifetime cancer risk associated with the radiation exposure using typical current scanner techniques is about 0.14% for paired CTC scans for a 50-year-old, and about half that for a 70-year-old. These values probably could be reduced by factors of 5 or 10 with optimized CTC protocols. CONCLUSIONS In terms of the radiation exposure, the benefit-risk ratio potentially is large for CTC.
Collapse
Affiliation(s)
- David J Brenner
- Center for Radiological Research, Columbia University Medical Center, New York, New York 10032, USA.
| | | |
Collapse
|