Contrast-induced nephropathy in patients with chronic kidney disease and peripheral arterial disease.

BACKGROUND: The risk for contrast-induced nephropathy (CIN) after intra-arterial application of an iodine-based contrast material is unknown for patients with chronic kidney disease (CKD) and peripheral arterial disease (PAD). PURPOSE: To investigate the incidence of CIN in patients with CKD and PAD. MATERIAL AND METHODS: This retrospective study was approved by the local ethics committee. One hundred and twenty patients with 128 procedures (73 with baseline eGFR in the range of 45-60 mL/min/1.73m(2), 55 with eGFR < 45 mL/min/1.73m(2)) were evaluated. All patients received intra-arterially an iodine-based low-osmolar contrast material (CM) after adequate intravenous hydration with isotonic NaCl 0.9% solution. CIN was defined as an increase in serum creatinine of more than 44 µmol/L within 4 days. The influence of patient-related risk factors (age, weight, body mass index, eGFR, serum creatinine, hypertension, diabetes mellitus, coronary heart disease, heart failure) and therapy-related risk factors (amount of CM, nephrotoxic drugs, number of CM applications) on CIN were examined. RESULTS: CIN developed in 0% (0/73) of procedures in patients with PAD and an eGFR in the range of 45-60 mL/min/1.73m(2) and in 10.9% (6/55) of procedures in patients with an eGFR <45 mL/min/1.73m(2). No risk factor significantly influenced the development of CIN, although baseline serum creatinine (P = 0.06) and baseline eGFR (P = 0.10) showed a considerable dependency. CONCLUSION: Patients with an eGFR in the range of 45-60 mL/min/1.73m(2) and PAD seem not at risk for CIN after intra-arterial CM application and adequate hydration. Whereas, an eGFR < 45 mL/min/1.73m(2) correlated with a risk of 10.9% for a CIN.

Clinical benefit of power-injectable port systems: a prospective observational study.

OBJECTIVE: To prospectively evaluate the clinical benefit of a central venous port system, which is approved for contrast media injection during contrast enhanced computed tomography. MATERIALS AND METHODS: At a university teaching hospital, 98 patients (59 female, 39 male; median age 61.7 years; range 23-83) had a power-injectable central venous port catheter system implanted. All implantations were performed under ultrasonographic and fluoroscopic guidance by interventional radiologists. Procedure related immediate (up to 24 h after implantation), early (<30 days after implantation) and late complications were documented. The frequency of port system use for contrast enhanced computed tomography scans was also considered. Any port capsule migration was assessed indirectly by determining the catheter tip position. The intended follow-up period was 180 days. RESULTS: An overall complication rate of 0.69 for 1,000 catheter days in 78 evaluated ports was recorded (12 ports affected, 15.4%). During the observational period, 40 of 104 contrast enhanced computed tomography scans were performed utilizing the port for contrast media administration (38.5%). 30 catheter tip retractions of more than 3 cm were observed in 82 patients (36.6%). Overall, tip dislocations were statistically more frequent in the female subgroup. CONCLUSION: The complication rate found in this study is comparable to those, which have been published for standard port systems. The utilization of the device for contrast media injection during contrast enhanced computed tomography scans should be increased. Finally, the port capsule has to be carefully positioned and fixed to prevent migration.

Effectiveness of sutureless percutaneous placement of cuffed tunneled hemodialysis catheters applying StatLock attachment devices.

PURPOSE: A prospective, randomized-controlled trail was conducted to evaluate the effectiveness of securing tunneled hemodialysis (HD) catheters with sutureless StatLock attachment devices (Bard Access Systems) compared to traditional suture fixation. METHODS: At a university teaching hospital 72 patients with chronic renal failure received cuffed tunneled HD catheters. In the study group (n=36) the HD catheters were secured with a sutureless StatLock attachment device, whereas the control group HD catheters were fixated with sutures only. The intended intermediate use of the tunneled HD catheters was 42 ± 7 days until the arteriovenous fistula was sufficient. All catheters were placed by an interventional radiologist using ultrasound for the puncture of the internal jugular vein. We evaluated the success and complication rate of tunneled catheter implantation. RESULTS: The primary success rate for implantation of HD catheters was 100%. There was an overall complication rate of 8.3% in the study group (one hematoma in the subcutaneous catheter tract and two central venous thromboses). In the control group the overall complication rate was 13.9% (two hematomas, one central venous thrombosis and two catheter displacements). The two catheter displacements required a HD catheter exchange. In addition, four local irritations at the HD catheter entry site were seen only in the control group and were rated as minor complications. CONCLUSIONS: The sutureless placement technique is safe and effective with a low complication rate, and is superior to the traditional suture fixation of tunneled catheters.

Precision of forty slice spiral computed tomography for quantifying aortic valve stenosis: comparison with echocardiography and validation against cardiac catheterization.

OBJECTIVES: We evaluated the precision of multislice spiral computed tomography (MSCT) for the quantification of aortic valve stenosis in comparison with echocardiography and cardiac catheterization. MATERIALS AND METHODS: An electrocardiogram-gated MSCT scan (detector collimation 40 x 6.25 mm, gantry rotation time 420 milliseconds, pitch 0.2, tube voltage 120 KV, tube current 333 mA) was performed in 32 patients with known aortic valve stenosis. In each patient the aortic valve orifice area (AVA) was determined by planimetry on MSCT and compared with the results obtained from transthoracic Doppler echocardiography (using the continuity equation) and cardiac catheterization (using the Gorlin formula). RESULTS: Planimetry of the AVA on MSCT was feasible in all cases. The AVA on MSCT (1.11 +/- 0.49 cm2) was significantly larger compared with echocardiography (0.81 +/- 0.37 cm2, P < 0.001) and cardiac catheterization (0.87 +/- 0.45 cm2, P < 0.001). The correlations between MSCT and echocardiography (r = 0.86, limits of agreement +/-0.52 cm2) and also between MSCT and cardiac catheterization (r = 0.90, limits of agreement +/-0.44 cm2) were good, but inferior to the correlation between echocardiography and cardiac catheterization (r = 0.94, limits of agreement +/-0.32 cm2). Using an AVA of 1.0 cm at cardiac catheterization as reference standard, the best cut-off level for detecting severe-to-critical stenosis at MSCT was an AVA of 1.20 cm, resulting in a sensitivity, specificity, and accuracy of 91%, 100%, and 94%, respectively. CONCLUSIONS: AVA determined by MSCT correlates well with echocardiography and cardiac catheterization. However, AVA derived from MSCT is consistently larger, requiring an adjustment of cut-off values for the classification of stenosis severity and therapeutic decision making.

Formalin-fixed blood clots--additional histological findings on computed tomography-guided fine-needle aspiration biopsies in comparison with core biopsies.

OBJECTIVE: We investigated the diagnostic yield of histological examined formalin-fixed blood clots (FFBCs) in comparison with the established procedures of fine-needle aspiration biopsy (FNAB) and core biopsy (CB) obtained by percutaneous puncture under computed tomography (CT) guidance. METHODS: A total of 76 CT-guided punctures with removal of tissue by means of all 3 different techniques (FFBC, FNAB, and CB) were performed. Specimens were obtained from the lung (n=18), mediastinum (n=10), upper abdominal organs (n=32), pelvis (n=4), retroperitoneum (n=4), bones (n=7), and neck (n=1). All results were correlated with the clinical course of the patients (minimum, 6 months; mean period, 10 months). The results of each technique were compared. Results of a combined use of FFBC and FNAB were analyzed. RESULTS: The overall sensitivity (regardless of biopsy site) was 79% for FFBC, 83% for FNAB, and 95% for CB. In chest biopsies, FFBC reached a sensitivity of 92%, FNAB of 86%, and CB of 96%. In liver biopsies, the sensitivities were 47%, 70%, and 88% for FFBC, FNAB, and CB and, for the remaining biopsy sites, 90%, 90%, and 100%, respectively. The combination of FFBC and FNAB showed higher sensitivities than FFBC and FNAB alone. Overall sensitivity for the combination was 88%, with 92%, 72%, and 100% for thorax, liver, and other locations. A definitive diagnosis was made by FFBC in 87% of cases, by FNAB in 74%, and by CB in 88%. The combination of FFBC and FNAB showed a definite diagnosis in 90% of the cases. A tentative diagnosis has been established in 12%, 7%, 5%, and 4%, respectively. In 4 cases (5%), all 3 techniques failed to yield reliable diagnoses. CONCLUSIONS: The examination of FFBCs is a useful supplement to the established technique of CT biopsy. In combination with FNAB, FFBC has a comparable sensitivity as CB in chest punctures and other extrahepatic lesions.

Acute myocardial ischemia after aortic valve replacement: a comprehensive diagnostic evaluation using dynamic multislice spiral computed tomography.

We describe the case of a 72-year-old man presenting with endocarditis and clinical signs of acute myocardial ischemia after biological aortic valve replacement. A comprehensive cardiac dynamic multislice spiral computed tomography demonstrated: (1) an endocarditic vegetation of the aortic valve; (2) a subvalvular leakage feeding a paravalvular pseudoaneurysm based on an aortic root abscess with subsequent compromise of the systolic blood flow in the left main coronary artery and the resulting myocardial perfusion deficit.

Early and late effects of passive epicardial constraint on left ventricular geometry: ellipsoidal re-shaping confirmed by electron-beam computed tomography.

BACKGROUND: Previous studies have shown that passive epicardial constraint using a cardiac support device (CSD) reduces left ventricular (LV) size. However, specific data describing LV shape and the time course of changes in LV geometry are still incomplete. Thus, the aim of this study was-using 3-dimensional data sets obtained by computed tomography (CT)-to test the hypothesis that the CSD not only alters LV size but also LV shape, and that short-term post-operative changes in LV geometry are maintained during long-term follow-up. METHODS: Ten patients with non-ischemic dilated cardiomyopathy underwent electron-beam CT examination before and again at 2.6 +/- 0.5 and 32.4 +/- 8.7 months after CSD implantation. At end-diastole and end-systole LV volumes, the length-to-width diameter ratio and a sphericity index were determined and ejection fraction and end-systolic meridional and circumferential wall stress were calculated. RESULTS: Implantation of the CSD led to a significant reduction in LV size, a more ellipsoidal LV shape and a subsequent decrease of LV wall stress post-operatively (p < 0.05 for each), but no substantial changes were found between short- and long-term follow-up (p > 0.05 each). Mean pre-operative and early and late post-operative end-diastolic values were 310.4 +/- 87.8, 235.5 +/- 102.0 and 229.4 +/- 103.1 ml for volume; 1.27 +/- 0.20, 1.37 +/- 0.20 and 1.38 +/- 0.20 for diameter ratio; and 0.78 +/- 0.22, 0.67 +/- 0.26 and 0.65 +/- 0.23 for sphericity index. A similar pattern was observed for end-systolic values. Ejection fraction was 23.4 +/- 6.2%, 32.9 +/- 11.6% and 34.4 +/- 14.9%. End-systolic meridional and circumferential wall stress was 182.2 +/- 45.6, 128.2 +/- 52.6, 130.6 +/- 56.7 kdyn/cm(2) and 411.5 +/- 94.0, 297.4 +/- 108.4 and 302.8 +/- 117.5 kdyn/cm(2), respectively. CONCLUSIONS: Three-dimensional data obtained by CT demonstrate that passive cardiac constraint leads not only to a size reduction but also to an ellipsoidal re-shaping. Our data indicate that these effects are primarily a short-term consequence of the CSD implantation but are maintained during long-term follow-up.

Contrast enhancement in electron beam tomography of the heart: comparison of a monomeric and a dimeric iodinated contrast agent in 59 patients.

RATIONALE AND OBJECTIVES: The aim of the study is to determine whether intravascular time-density course and visualization of the coronary arteries differ with use of a hyperosmolar monomeric versus an iso-osmolar dimeric contrast agent in electron beam tomography (EBT) of the heart. MATERIALS AND METHODS: Fifty-nine patients underwent EBT of the coronary arteries using the monomeric ioversol or the dimeric iodixanol at the same concentration of 320 mg I/mL. Contrast volume was determined relative to body surface area and injected over 40 seconds. Intravascular time-density curves were created for quantitative analysis. For qualitative assessment, visualization of coronary arteries on axial scans and three-dimensional reconstructions was scored. Patients were matched for contrast flow, transit time, and mean pulse rate for statistical analysis. RESULTS: Ioversol produced a significantly greater increase in intravascular density for up to 30 seconds after injection (P < .01) compared with iodixanol. No difference between the two contrast media was seen in the qualitative assessment. CONCLUSION: Monomeric and dimeric contrast media differ in their time-density curves at coronary EBT, a reason for which is not apparent. Qualitative evaluation of coronary arteries is not affected by this difference.

Pictorial review: electron beam computed tomography and multislice spiral computed tomography for cardiac imaging.

Electron beam computed tomography (EBCT) revolutionized cardiac imaging by combining a constant high temporal resolution with prospective ECG triggering. For years, EBCT was the primary technique for some non-invasive diagnostic cardiac procedures such as calcium scoring and non-invasive angiography of the coronary arteries. Multislice spiral computed tomography (MSCT) on the other hand significantly advanced cardiac imaging through high volume coverage, improved spatial resolution and retrospective ECG gating. This pictorial review will illustrate the basic differences between both modalities with special emphasis to their image quality. Several experimental and clinical examples demonstrate the strengths and limitations of both imaging modalities in an intraindividual comparison for a broad range of diagnostic applications such as coronary artery calcium scoring, coronary angiography including stent visualization as well as functional assessment of the cardiac ventricles and valves. In general, our examples indicate that EBCT suffers from a number of shortcomings such as limited spatial resolution and a low contrast-to-noise ratio. Thus, EBCT should now only be used in selected cases where a constant high temporal resolution is a crucial issue, such as dynamic (cine) imaging. Due to isotropic submillimeter spatial resolution and retrospective data selection MSCT seems to be the non-invasive method of choice for cardiac imaging in general, and for assessment of the coronary arteries in particular. However, technical developments are still needed to further improve the temporal resolution in MSCT and to reduce the substantial radiation exposure.

A novel model to test accuracy and reproducibility of MDCT scan protocols for coronary calcium in vivo.

OBJECTIVES: We compared the accuracy and reliability of prospectively triggered, retrospectively ECG gated, and non-gated CT image reconstruction for measurements of coronary artery calcification (CAC) in vivo using a novel animal model. MATERIALS AND METHODS: In six Yorkshire farm pigs, prefabricated chains of cortical bone fragments were sutured over the epicardial bed of the major coronary arteries. Using a 4-slice MDCT scanner, each animal was imaged with two different protocols: sequential acquisition with prospective ECG triggering, and spiral acquisition with retrospectively ECG gated image reconstruction- non-gated reconstructions were also generated from these latter scans. Two independent observers measured the 'Agatston score' (AS), the calcified volume (CV), and mineral mass (MM). To calculate accuracy of MM measurements the ash weight of the burned bone fragments was compared to MDCT derived MM. RESULTS: Six pigs successfully underwent surgery and CT imaging (mean heart rate: 86+/-12 bpm). MM measurements from prospectively ECG triggered CT sequential scans were more accurate (p<0.02) and reproducible (p=0.05) than sequential CT scans without ECG triggering or spiral acquisition using retrospective ECG gating. CONCLUSIONS: At high heart rates prospective ECG triggered image reconstruction is more accurate and reproducible for CAC scoring than retrospective ECG gated reconstruction and non-gated reconstruction.

Percutaneous discography: comparison of low-dose CT, fluoroscopy and MRI in the diagnosis of lumbar disc disruption.

AIM: To compare the diagnostic accuracy of low-dose computed tomography (CT), magnetic resonance imaging (MRI) and fluoroscopy in percutaneous discography in patients scheduled for lumbar spondylodesis. MATERIAL AND METHODS: Within a prospective pilot study, 18 disc segments of 11 patients with radicular or pseudoradicular pain prior to anteroposterior spondylodesis were evaluated. After injection of a mixture of non-ionic iodine-containing contrast agent and gadolinium-based contrast medium into the disc spaces, all patients underwent conventional fluoroscopy, as well as low-dose CT and MRI. The occurrence of memory pain during contrast injection was recorded. CT, MRI and fluoroscopic images were analyzed independently by two readers blinded to the clinical findings. RESULTS: There was 100% agreement between CT and MRI discography in the detection, localization and grading of degenerative changes. In contrast, conventional fluoroscopy identified only 9 of the 12 abnormal segments. Memory pain following puncture was identified in 3 of the 12 affected segments. SUMMARY: Low-dose CT and MRI discography have a similar accuracy in the assessment of disc disruption and they are superior to fluoroscopic discography.

Assessment of mitral valve regurgitation at electron-beam CT: comparison with Doppler echocardiography.

PURPOSE: To prospectively compare mitral valve regurgitation fractions calculated at electron-beam computed tomography (CT) (Doppler echocardiography as reference standard) and to evaluate accuracy of electron-beam CT volume and flow measurements compared with magnetic resonance (MR) imaging results. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Volume and flow measurements were performed at electron-beam CT in 219 patients (197 men, 22 women; mean age, 61.5 years +/- 10.4 [standard deviation]), of whom 157 had known isolated mitral valve regurgitation. Regurgitation volume was calculated as the difference between left ventricular total and forward stroke volumes. Regurgitation fractions were compared with corresponding echocardiographic grades (grades 0-IV) by using Spearman rank correlation and a weighted kappa test. In 22 patients, CT volume and flow measurements were compared with MR results by using intraclass correlation. RESULTS: Regurgitation fractions at CT correlated well with echocardiographic grading (rank correlation coefficient, r(S) = 0.82; P < .05). Mean regurgitation fractions for echocardiographic grades 0, I, II, III, and IV were 3.1% +/- 6.2, 12.7% +/- 9.9, 25.3% +/- 12.3, 40.4% +/- 11.5, and 55.9% +/- 13.7, respectively. The most suitable thresholds for differentiating echocardiographic grades were calculated regurgitation fractions of 6%, 20%, 30%, and 44%; with these thresholds, individual echocardiographic grades were differentiated (grades 0 vs I-IV, 0-I vs II-IV, 0-II vs III-IV, and 0-III vs IV, respectively) with sensitivities of 89%, 87%, 86%, and 93% and specificities of 81%, 87%, 92%, and 91%, respectively. There was perfect agreement in classification of mitral valve insufficiency between electron-beam CT and echocardiography in 134 (61%) patients and a mismatch by one grade in 72 (33%) and by two grades in 13 (6%) (kappa = 0.84). Intraclass correlation coefficients between CT and MR imaging for total and forward stroke volumes and regurgitation volume and fraction were 0.88, 0.79, 0.93, and 0.89, respectively. CONCLUSION: Electron-beam CT provides quantitative information on severity of mitral valve regurgitation, but semiquantitative classification of regurgitation showed mismatch between electron-beam CT and Doppler echocardiography by at least one grade in more than one-third of all patients.

Quantification of functional mitral valve regurgitation in patients with congestive heart failure: comparison of electron-beam computed tomography with cardiac catheterization.

OBJECTIVES: We sought to determine the agreement between electron-beam computed tomography (CT) and cardiac catheterization for the quantification of mitral regurgitation and to evaluate their association with echocardiographic assessment. MATERIAL AND METHODS: Fifty patients with congestive heart failure were examined both by electron-beam CT and catheterization to calculate mitral regurgitation volume and fraction based on the difference between the left ventricular stroke and aortic flow volume. The severity of regurgitation was also compared with visual assessment by echocardiography (grade, 0-4+). RESULTS: The mean values for the mitral regurgitation volume and fraction did not differ significantly between electron-beam CT and catheterization (mean differences: 0.2 mL/m2 and -0.9%, P > 0.05 each, limits of agreement: -14.0 to 14.4 mL/m2 and -26.3 to 24.5%, respectively) and showed a good correlation (r = 0.79 and r = 0.76, respectively; P < 0.05 each). Good levels of correlation were observed between echocardiographic severity grading and quantitative measurements of regurgitation volume and fraction, which were somewhat better between echocardiography and electron-beam CT (rS = 0.78 and rS = 0.84, respectively; P < 0.05 each) than between echocardiography and catheterization (rS = 0.72 and rS = 0.81, respectively; P < 0.05 each). CONCLUSION: Our results suggest that electron-beam CT allows for quantification of mitral valve regurgitation with similar accuracy as cardiac catheterization. Measurements with both modalities correlated well with the results of echocardiographic assessment.

Comparison of electron beam computed tomography with magnetic resonance imaging in assessment of right ventricular volumes and function.

OBJECTIVE: Intraindividual comparison of right ventricular volumes and function using electron beam computed tomography (EBT) and magnetic resonance imaging (MRI). METHODS: Twenty-seven patients with a known cardiac history were referred for evaluation of ventricular function parameters. The following standardized protocols were used: contrast-enhanced multislice mode EBT and gradient echo sequence MRI. Right ventricular end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) were calculated using a slice summation method. Interobserver variability was calculated. RESULTS: The correlation between the 2 methods was: r = 0.901 for EDV, r = 0.938 for ESV, r = 0.823 for SV, and r = 0.953 for EF. Electron beam computed tomography overestimated EDV and ESV slightly when compared with MRI (P < 0.05). No significant differences (P > 0.05) were found between SV and EF. Mean values determined by EBT and MRI were as follows: 168.6 +/- 62.3 mL and 153.7 +/- 59.1 mL for EDV, 104.7 +/- 60.4 mL and 95.1 +/- 54.8 mL for ESV, 63.2 +/- 19.3 mL and 58.7 +/- 19.8 mL for SV, and 40.2% +/- 14.1% and 40.2% +/- 13.6% for EF, respectively. Interobserver variability ranged between 1.0% and 3.2%. CONCLUSION: Electron beam computed tomography shows good agreement with a close correlation and an acceptable interobserver variability for right ventricular volumes and global function, with a small but significant overestimation of EDV and ESV when compared with MRI.

Changes in right ventricular dimensions and performance after passive cardiac containment.

BACKGROUND: Previous studies have shown that the cardiac support device (CSD) improves left ventricular structure and function in patients with heart failure by preventing further cardiac enlargement. The aim of this study was to identify effects on the right ventricle (RV). METHODS: Ten male patients with idiopathic dilated cardiomyopathy underwent electron-beam computed tomographic (CT) examination within 1 month before, and 6 to 9 months after CSD implantation. The RV end-diastolic and end-systolic volumes (EDV, ESV) and diameters (EDD, ESD), stroke volume (SV), ejection fraction (EF), total and forward RV output (RVO, fRVO), and tricuspid regurgitation fraction (TRF) were calculated. RESULTS: The EDV measurements decreased from 182.1 +/- 49.6 to 137.5 +/- 37.0 mL, ESV from 114.8 +/- 47.0 to 68.3 +/- 23.8 mL, EDD from 48.2 +/- 6.6 to 41.6 +/- 7.1 mm, and ESD from 39.6 +/- 6.9 to 32.7 +/- 6.5 mm (p < 0.05 for each). Ejection fraction increased from 38.5 +/- 8.9 to 52.0% +/- 7.7% and fRVO from 4.0 +/- 0.8 to 4.6 +/- 1.1 L/min (each with p < 0.05). TRF decreased from 18.2 +/- 14.1 to 10.4% +/- 13.5%, whereas SV and RVO remained nearly unchanged. Postoperatively, RV volumes, EF, and fRVO were not different from 15 age- and gender-matched normal control patients. CONCLUSIONS: Implantation of a CSD leads to a decrease in RV size and improved RV performance. These data together with the results of previous studies demonstrating improved left ventricular structure and function confirm the biventricular nature of recovery with the CSD.

Acute myocardial infarction: contrast-enhanced multi-detector row CT in a porcine model.

PURPOSE: To assess the role of contrast material-enhanced retrospectively electrocardiographically (ECG) gated multi-detector row computed tomography (CT) in the detection of acute myocardial infarction in a porcine model of total coronary occlusion. MATERIALS AND METHODS: Seven Yorkshire farm pigs were studied with contrast-enhanced retrospectively ECG-gated multi-detector row CT 3 hours after total occlusion of the distal left anterior descending artery (n = 5) or the second diagonal branch (n = 2). Reformatted short-axis end-systolic and end-diastolic CT data sets were assessed for myocardial perfusion deficits, coronary occlusion, and abnormal myocardial wall motion. Perfusion deficits were compared with microsphere-determined blood flow and triphenyltetrazolium chloride (TTC)-stained tissue samples for infarct assessment by using Bland-Altman analysis and analysis of variance. RESULTS: Myocardial perfusion deficits, occlusion of the left anterior descending artery or second diagonal branch, and akinesis of the infarcted segment were identified in all five animals that completed the study. One animal died, and one data set had nondiagnostic image quality. The CT end-diastolic (mean, 16.1% +/- 4.8 [SD]; range, 8.6%-22.2%) and end-systolic (mean, 17.0% +/- 6.4; range, 8.7%-26.8%) volume of perfusion deficit was similar to that of infarcted tissue at TTC staining (mean, 13.6% +/- 6.0; range, 7.8%-30.9%). Infarcted myocardium at CT demonstrated a 76.1% reduction in microsphere-determined blood flow and a significant reduction of myocardial CT attenuation compared with normal myocardium (P <.01). Myocardial wall motion analysis demonstrated absence of systolic wall thickening in infarcted myocardium. CONCLUSION: Multi-detector row CT with retrospective ECG gating permits the detection and further characterization of acute myocardial infarction in a porcine model of complete coronary occlusion.

Image quality of noninvasive coronary angiography using multislice spiral computed tomography and electron-beam computed tomography: intraindividual comparison in an animal model.

OBJECTIVE: Comparison of coronary artery visualization by multislice spiral CT (MSCT) and electron-beam CT (EBCT). MATERIALS AND METHODS: Six minipigs underwent MSCT (collimation 4 x 1 mm, gantry rotation time 500 milliseconds, acquisition time per cardiac cycle 126 +/- 30 milliseconds) and EBCT (slice thickness 1.5 mm, acquisition time per scan 100 milliseconds). Visualized vessel length and contour sharpness was measured, contrast-to-noise ratios were calculated, and the frequency of motion artifacts were evaluated. RESULTS: MSCT depicted significantly longer segments of the coronary tree than EBCT (length: 248.8 vs. 222.8 mm; P < 0.05), delineated the vessel contours more sharply (slope of density curves: 219.2 vs. 160.2 DeltaHU/mm; P < 0.05), and had a higher contrast-to-noise ratio (13.4 vs. 7.3; P < 0.05). The frequency of motion artifacts did not differ between both modalities (94.7% vs. 95.7% of visualized vessel length; P > 0.05). CONCLUSIONS: Because its higher spatial resolution and lower image noise, MSCT seems to be superior to EBCT in the visualization of the coronary arteries. Despite different temporal resolutions motion artifacts seem to be similar with both modalities.

Isotropic half-millimeter angiography of coronary artery bypass grafts with 16-slice computed tomography.

BACKGROUND: Computed tomography (CT) with four detector rows and magnetic resonance imaging (MRI) are still of limited value for the assessment of coronary artery bypass grafts (CABG). We investigated the abilities of 16-slice CT in these patients. METHODS: A retrospective analysis of all noninvasive coronary angiographies with multislice computed tomography (MSCT; Aquilion, Toshiba) on patients with CABG referred to our institution between October 2002 and April 2003 was conducted. MSCT angiography was performed using a standard protocol (0.5-seconds rotation time, 16 x 0.5 mm detector collimation, 120 kV, 250 to 300 mA, and 0.25 pitch). None of the patients received beta-blockers to reduce the heart rate. Seventy-five CABGs (20 arterial grafts and 55 venous grafts) in 27 patients were evaluated for patency and adequate diagnostic quality by two radiologists in consensus. RESULTS: All arterial and venous grafts were depicted with adequate diagnostic quality and were eligible for evaluation. Fifteen occlusions and five significant stenoses (at least 50%) could be identified. All of the proximal and 99% of the distal anastomoses were eligible. One distal anastomosis of an arterial graft was not assessable due to surgical clip artifacts. The length of the acquisition window was 174 +/- 46 ms (range 71 to 234 ms). The majority of the patients (70%) had a heart rate above 65 beats/min. However, due to the improved temporal and spatial resolution none of the examinations had an insufficient image quality. CONCLUSIONS: MSCT angiography with 16 detector rows and an isotropic high resolution reliably depicts CABG with adequate diagnostic quality.