Automatic bone and plaque removal using dual energy CT for head and neck angiography: feasibility and initial performance evaluation.

PURPOSE: We sought to evaluate the feasibility and efficiency of dual energy (DE) bone and plaque removal in head and neck CT angiography. MATERIALS AND METHODS: 20 patients with suspected carotid stenoses received head and neck DE-CTA as part of their pre-interventional workup. Visual grading using multiplanar reformations (MPR), thick slab maximum intensity projections (MIP) and quantitative vessel analysis (QVA) of stenoses was performed prior and after DE bone removal. Results were evaluated for the detection of relevant stenoses (vessel area reduction >70%). Vessel segmentation errors were analyzed. RESULTS: Segmentation errors occurred in 19% of all vessel segments. Nevertheless, most post-bone removal artifacts could be recognized using the MPR technique for reading. Compared to MPR reading prior to bone removal, sensitivity, specificity, positive and negative predictive values after bone removal were 100%, 98%, 88% and 100% for MPR reading and 100%, 91%, 63% and 100% for exclusive MIP reading, respectively. There was a good agreement between the QVA results prior and post-DE plaque removal (r(2)=0.8858). CONCLUSION: DE bone and plaque removal for head and neck angiography is feasible and offers a rapid and highly sensitive overview over vascular head and neck studies. Due to a slightly limited specificity of the MIP technique due to segmentation errors, possible stenoses should be verified and graded using MPR techniques.

Prevalence of acute reactions to iopromide: postmarketing surveillance study of 74,717 patients.

BACKGROUND: Iodinated X-ray contrast media (CM) are recognized worldwide to be among the safest and most widely used injectable drugs. However, adverse drug reactions (ADRs) may still occur, ranging in severity from minor disturbances to severe and potentially fatal complications. PURPOSE: To prospectively determine the incidence and characteristics of acute ADRs during clinical utilization of a single nonionic monomeric contrast agent, iopromide, in routine radiological practice in a large number of nonselected patients. MATERIAL AND METHODS: 74,717 patients were enrolled in a prospective international postmarketing surveillance registry with iopromide (Ultravist; Bayer Schering Pharma AG, Berlin, Germany). A standardized questionnaire was used to collect the following patient information from 762 centers in 27 countries: baseline demographics, risk factors, premedication regimen, type of examination, route of injection, volume and selected concentration of iopromide, and overall tolerance to CM (utilizing specific criteria and descriptors). RESULTS: The overall rate of ADRs, including tolerance indicators (TI) (i.e., heat sensation and pain at the injection site), was 2%; when TIs were excluded, the rate was 1.5%. Fourteen serious adverse reactions were reported (rate 0.02%), of which none were fatal. There was a higher incidence of ADRs among women and for the age group ranging between 18 and 30 years. Patients with established risk factors, such as a history of previous CM reaction or allergic diathesis (7.4% and 4.1%, respectively), were at an increased risk for developing an ADR when compared to patients without risk factors (1.2%). The incidence of ADRs was not altered by the use of premedication. CONCLUSION: The safety of iopromide in routine clinical practice was shown to be comparable to the published safety profiles of other nonionic iodinated contrast agents. Adverse drug reaction rates were affected by age, gender, and risk factors (especially previous CM reactions or allergies), but not by premedication.

Characterization of coronary atherosclerosis by dual-source computed tomography and HU-based color mapping: a pilot study.

To assess HU-based color mapping for characterization of coronary plaque, using intravascular ultrasound virtual histology (IVUS-VH) as a standard of reference. Dual-source computed tomography and IVUS-VH were prospectively performed in 13 patients. In five lesions, HU thresholds of the color-coding software were calibrated to IVUS-VH. In a 15-lesion verification cohort, volumes of vessel, lumen and plaque or percentages of lipid, fibrous and calcified components were obtained through use of pre-set HU cut-offs as well as through purely visual adjustment of color maps. Calibrated HU ranges for fatty or fibrous plaque, lumen and calcification were -10-69, 70-158, 159-436 and 437+. Using these cut-offs, HU-based analysis achieved good agreement of plaque volume with IVUS (47.0 vs. 51.0 mm(3)). Visual segmentation led to significant overestimation of atheroma (61.6 vs. 51.0 mm(3); P = 0.04) Correlation coefficients for volumes of vessel, lumen and plaque were 0.92, 0.87 and 0.83 with HU-based analysis or 0.92, 0.85 and 0.71 with visual evaluation. With both methods, correlation of percentage plaque composition was poor or insignificant. HU-based plaque analysis showed good reproducibility with intra-class correlation coefficients being 0.90 for plaque volume and 0.81, 0.94 or 0.98 for percentages of fatty, fibrous or calcified components. With use of optimized HU thresholds, color mapping allows for accurate and reproducible quantification of coronary plaque.

Noninvasive coronary angiography using 64-slice spiral computed tomography in an unselected patient collective: effect of heart rate, heart rate variability and coronary calcifications on image quality and diagnostic accuracy.

OBJECTIVE: The aim of this study was to assess the impact of heart rate, heart rate variability and calcification on image quality and diagnostic accuracy in an unselected patient collective. SUBJECTS AND METHODS: One hundred and two consecutive patients with known or suspected coronary artery disease underwent both 64-MSCT and invasive coronary angiography. Image quality (IQ) was assessed by independent observers using a 4-point scale from excellent (1) to non-diagnostic (4). Accuracy of MSCT regarding detection or exclusion of significant stenosis (>50%) was evaluated on a per segment basis in a modified AHA 13-segment model. Effects of heart rate, heart rate variability, calcification and body mass index (BMI) on IQ and accuracy were evaluated by multivariate regression. IQ and accuracy were further analysed in subgroups of significant predictor variables and simple regression performed to calculate thresholds for adequate IQ. RESULTS: Mean heart rate was 68.2+/-13.3 bpm, mean heart rate variability 11.5+/-16.0 beats per CT-examination (bpct) and median Agatston score 226.5. Average IQ score was 2+/-0.6 whilst diagnostic quality was obtained in 89% of segments. Overall sensitivity, specificity, PPV or NPV was 91.2%, 99.2%, 95.3% or 98.3%. According to multivariate regression, overall IQ was significantly related to heart rate and calcification (P=0.0038; P<0.0001). The effect of heart rate variability was limited to IQ of RCA segments (P=0.018); BMI was not related to IQ (P=0.52). Calcification was the only predictor variable with significant effect on the number of non-diagnostic segments (P<0.0001). In a multivariate regression, calcification was also the single factor with impact on diagnostic accuracy (P=0.0049). CONCLUSION: Whilst heart rate, heart rate variability and calcification all show an inverse correlation to IQ, severe calcium burden remains the single factor with translation of such effect into decrease of diagnostic accuracy.

Sixty-four-slice CT in the assessment of global and regional left ventricular function: comparison with MRI in a porcine model of acute and subacute myocardial infarction.

The purpose was to assess 64-slice CT in the analysis of global and regional ventricular function, using a model of acute and subacute myocardial infarction in comparison with cine-MRI. Seven pigs underwent standard MSCT and MRI examination a median 1 and 21 days following creation of reperfused myocardial infarction. Endocardial and epicardial contours were manually defined and ventricular volumes calculated according to Simpson's method. Results were compared by Pearson's correlation coefficient and Blant-Altman analysis. Wall motion was assessed on cine-images and evaluated by kappa statistics. MSCT revealed a strong correlation with cine-MRI regarding quantification of end-diastolic volume (EDV; r = 0.97), end-systolic volume (ESV; r = 0.97), stroke volume (SV; r = 0.94), ejection fraction (EF; r = 0.95) or myocardial mass (MM; r =0.94 ). Minor overestimation was observed for EDV and ESV (bias -1.7 ml; -1.5 ml; P=0.095; 0.025), whilst the mean difference for EF was found to be negligible (bias 0.9%; P = 0.18). Both modalities showed a 96.2% segmental agreement in regional wall motion (weighted-kappa 0.91 for 238 segments). This was true for both acute and subacute infarct phase and MSCT, and thereby enabled accurate intraindividual follow-up of segmental dysfunction. Sixty-four-slice CT allows for reliable analysis of global cardiac function and, moreover, provides accurate evaluation of wall motion in acute and subacute myocardial infarct.

Evaluation of dose exposure in 64-slice CT colonography.

The radiation exposure of four different 64-slice MDCT-colonography (CTC) protocols was evaluated using an Alderson-Rando phantom. Protocols using 30 mAs (collimation 20 x 1.2 mm), 50 mAs (collimation 20 x 1.2 and 64 x 0.6 mm) and 80 mAs (20 x 1.2 mm) representing screening low-dose, routine, narrow collimation and oncologic staging setups were measured with an Alderson-Rando phantom (Alderson Research Laboratories Inc.). Scans were performed on a 64-row MDCT (SOMATOM Sensation 64, Siemens) simulating the prone and supine positions with a constant voltage of 120 kV. Dose values (male/female) were 2.5/2.9, 3.8/4.2, 4.2/4.5 and 5.7/6.4 mSv for 30, 50 (20 x 1.2 and 64 x 0.6 mm) and 80 mAs, respectively. Measurements showed an elevated dose for females (11.5% mean; compared to males). Use of narrow collimation combined with 50 mAs resulted in a small increase of dose exposure of 10.5 (male) and 7.1% (female). Gonad doses ranged from 0.9 to 2.6 mSv (male) and from 1.5 to 3.5 mSv (female). In all protocols, the stomach wall, lower colon, urinary bladder and liver were slightly more highly exposed (all <2.3 mSv) than the other organs, and the breast dose was <0.3 mSv in every setup. Values of radiation exposure in 64- and 16-slice CTC differ only marginally when using the narrow collimation. In 64-slice CTC, the use of narrow (64 x 0.6 mm) collimation shows slightly elevated dose values compared to wider (20 x 1.2 mm) collimation.

Late myocardial enhancement assessed by 64-MSCT in reperfused porcine myocardial infarction: diagnostic accuracy of low-dose CT protocols in comparison with magnetic resonance imaging.

The purpose was to assess the practicability of low-dose CT imaging of late enhancement in acute infarction. Following temporary occlusion of the second diagonal branch, seven pigs were studied by multislice computed tomography (MSCT) and magnetic resonance imaging (MRI). Thus, 64-slice CT was performed at 3, 5, 10 and 15 min following the injection of contrast medium according to a bolus/low-flow protocol. Standard parameters of 120 kV and 800 mAs were compared with 80 kV and 400 mAs in various combinations. Infarct volumes were assessed as percentage of the ventricle for both MSCT and MR images. CT density values for viable and infarcted myocardium were obtained and image quality assessed. Mean infarct volume as measured by MRI was 12.33+/-7.06%. MSCT achieved best correlation of volumes at 5 and 10 min. Whilst lowering of tube current resulted in poor correlation, tube voltage did not affect accuracy of infarct measurement (r (2)=0.92 or 0.93 at 5 min, 800 mAs and 80 or 120 kV). In terms of image quality, greater image noise with 80 kV was compensated by significantly better contrast enhancement between viable and non-viable myocardium at lower voltage. Myocardial viability can accurately be assessed by MSCT at 80 kV, which ensures higher contrast for late enhancement and yields good correlation with MRI.

Sixty-four-MSCT in the characterization of porcine acute and subacute myocardial infarction: determination of transmurality in comparison to magnetic resonance imaging and histopathology.

OBJECTIVE: The aim of this study was to assess the accuracy of MSCT in characterizing myocardial infarction (MI) and, thereby, determine the extent of early perfusion defect (ED), microvascular obstruction (MO) and transmural depth of late enhancement (LE) in comparison to MRI and histology. MATERIALS AND METHODS: Seven pigs were studied with MSCT (Somatom Sensation 64) and MRI (Magnetom Sonata) a median 1 and 21 days following temporary occlusion of a diagonal branch and creation of small reperfused infarction. For depiction of ED, CT images were acquired in the early arterial phase and following 35 s; LE and MO were evaluated on images obtained at 3, 5, 10 and 15 min. Thereby, a bolus/low-flow contrast injection protocol was used. Triphenyltetrazolium-chloride (TTC) stain and histology were obtained. Volumes of enhancement patterns were assessed as percentage of the ventricle and compared by Bland-Altman analysis. Segmental co-localization and graded transmurality was evaluated with weighted-kappa-test. RESULTS: Close spatial agreement was observed for MRI-MO and MSCT-MO (bias=0.55; CI=-1.49 to 2.60 at 5 min MSCT), TTC and MSCT-LE (bias=-1.28; CI=-3.76 to 1.19) or MRI-LE and MSCT-LE (bias=-0.79; CI=-4.19 to 2.60). There was good segmental co-localization for MO (weighted kappa=0.93) and high agreement for transmural extent of TTC, MRI-LE and MSCT-LE (weighted kappa=0.84 TTC versus MSCT; 0.86 MRI versus MSCT). Arterial and 35s ED significantly underestimated infarct size and showed poor segmental or transmural agreement (weighted kappa=0.33; 0.44). CONCLUSIONS: MSCT late-scans not only reliably depict size of MO and LE in acute or subacute infarct phases but, moreover, allow for accurate determination of LE transmurality.

Non-invasive coronary angiography with 16-slice spiral computed tomography: image quality in patients with high heart rates.

The purpose of this study was to assess segment image quality at high heart rates using 16-slice computed tomography and differential reconstruction for major coronary vessels. According to the following protocol, 16-slice CT coronary angiography in 46 patients with a mean heart rate of 86.3+/-11.8 was reconstructed. At three transverse planes, preview series were obtained and motion artifacts evaluated in 5% increments from 0-95% within the cardiac cycle. Relying on image quality in the previews, reconstructions were performed at three z-positions for each patient. Segment image quality was assessed in terms of artifacts and visibility. The effects of heart rate and trigger delay on image quality were analyzed. Optimal image quality was achieved at 25 to 35% of the cardiac cycle for the left circumflex (CX) and right coronary artery (RCA) or 30 to 40% for the left main (LM) and left anterior descending artery (LAD). Sixteen-slice CT and differential reconstruction produced good image quality with a low percentage of motion-degraded proximal and middle segments (8.8%). Grades were 1.5 for the LM, 1.9 for the LAD, 2.0 for the CX and 2.3 for the RCA. At high heart rates, good image quality of the coronary arteries is achieved by 16-slice CT and a sophisticated reconstruction strategy at peak to late systole.

Image quality and diagnostic accuracy of 16-slice multidetector computed tomography for the detection of coronary artery disease in obese patients.

BACKGROUND: Cardiac multislice spiral computed tomography (MSCT) scanners permit visualization of the coronary arteries with an overall good sensitivity (sens) and specificity (spec). However, in obese patients (pts), who are at higher risk to develop coronary artery disease (CAD), image quality of MSCT is supposed to be limited. At present, there are no data whether the accuracy of MSCT depends on the body mass index (BMI). Thus, we compared the catheter-controlled MSCT results from normal weight and obese pts in a cohort of 117 pts with regard to sens, spec, positive predictive value (PPV), negative predictive value (NPV) and image quality. METHODS AND MATERIAL: In all, 21 normal weight pts (group I: BMI<25, 64.6+/-11.1 years, number of risk factors 2.1+/-1.1), 60 pts with mild overweight (group II: BMI 25-30, 64.6+/-8.9 years, number of risk factors 3.4+/-1.0) and 36 obese pts (group III: BMI >30, 63.0+/-8.5 years, number of risk factors 3.4+/-0.9) were examined by MSCT (Sensation 16 Speed 4 D((R)), Siemens, Germany, gantry rotation time 375 ms) and invasive coronary angiography. MSCT results were compared blinded to the results of the coronary angiography with regard to the presence or absence of a significant stenosis (>50%) in a modified AHA 13 segment (sgt) model. Image quality was assessed on a qualitative scale between 1 (very good) and 5 (insufficient image quality) for each sgt. RESULTS: Sens, spec, PPV and NPV were statistically not different in all three groups (I: 0.88/0.97/0.91/0.96, II: 0.83/0.97/0.88/0.95, III: 0.87/0.99/0.96/0.96). 3 pts (group I 1, group II 2) had to be excluded from analysis due to technical problems. Group I had significantly less risk factors (P < 0.001) and image quality was significantly better than in group II and III (P < 0.05). Group II and III did not differ with regard to risk factors or image quality. CONCLUSIONS: Overweight and obesity have an impact on MSCT image quality but did not hamper the diagnostic accuracy. Thus, MSCT is a noninvasive method to detect or rule out CAD also in pts with higher BMI. These retrospective data have to be confirmed in larger prospective trials.

Image quality and diagnostic accuracy of non-invasive coronary imaging with 16 detector slice spiral computed tomography with 188 ms temporal resolution.

OBJECTIVE: To evaluate image quality and clinical accuracy in detecting coronary artery lesions with a new multidetector spiral computed tomography (MDCT) generation with 16 detector slices and a temporal resolution of 188 ms. METHODS: 124 consecutive patients scheduled for invasive coronary angiography (ICA) were additionally studied by MDCT (Sensation 16 Speed 4D). MDCTs were analysed with regard to image quality and presence of coronary artery lesions. The results were compared with ICA. RESULTS: 120 of 124 scans were successful. The image quality of all remaining 120 scans was sufficient (mean (SD) heart rate 64.2 (9.8) beats/min, range 43-95). The mean calcium mass was 167 (223) mg (range 0-1038). Thirteen coronary segments were evaluated for each patient (1560 segments in total). Image quality was graded as follows: excellent, 422 (27.1%) segments; good, 540 (34.6%) segments; moderate, 277 (17.7%) segments; heavily calcified, 215 (13.8%) segments; and blurred, 106 (6.8%) segments. ICA detected 359 lesions with a diameter stenosis > 50% and MDCT detected 304 of 359 (85%). Sensitivity, specificity, and positive and negative predictive values were 85%, 98%, 91%, and 96%, respectively. The correct clinical diagnosis (presence or absence of at least one stenosis > 50%) was obtained for 110 of 120 (92%) patients. CONCLUSIONS: MDCT image quality can be further improved with 16 slices and faster gantry rotation time. These results in an unselected population underline the potential of MDCT to become a non-invasive diagnostic alternative, especially for the exclusion of coronary artery disease, in the near future.

Clinical use of multislice spiral computed tomography in 210 highly preselected patients: experience with 4 and 16 slice technology.

OBJECTIVE: To report an initial experience with multislice spiral computed tomography (MSCT) coronary imaging, as well as differences in diagnostic accuracy between 4 slice and 16 slice MSCT technology. METHODS AND RESULTS: 210 patients underwent MSCT coronary angiography (4 slices, n = 120; 16 slices, n = 90; suspicion of coronary artery disease, n = 158; suspicion of restenosis, n = 52). Recommendations for further diagnostic tests were based on the MSCT results. Patients were interviewed by telephone after a mean (SD) of 449 (169) days to evaluate their further clinical course. MSCT detected significant lesions in 90 of 210 (43%) patients and invasive coronary angiography (ICA) was recommended. MSCT excluded significant lesions in 120 of 210 (57%) patients. ICA was actually performed in 44 of 210 (21%) patients (corresponding results, 27 of 44 (61%); false positive, 11 of 44 (25%); false negative, 6 of 44 (14%)). No significant differences were found between 4 and 16 slice imaging. No major cardiac event occurred during follow up. CONCLUSIONS: MSCT was found to be useful to evaluate the need for invasive diagnostic procedures. However, the false negative results underline that further improvements of image quality are required before MSCT can replace ICA in carefully selected patients.

[Left ventricular functional parameters: comparison of 16-slice spiral CT with MRI]. / Bestimmung linksventrikulärer Funktionsparameter: Vergleich von 16-Zeilen-Mehrschicht-CT mit der MR-Tomographie.

PURPOSE: The quantitative measurement of left ventricular functional parameters using multislice computed tomography (MSCT) with retrospective ECG-gating and comparison of the results with magnetic resonance imaging (MRI). MATERIALS AND METHODS: Thirty-one patients with suspected or known coronary artery disease underwent MSCT angiography with retrospective ECG-gating (Sensation 16, Siemens). Based on the CT data set, short axis reformations of the left ventricle were performed for functional analysis. On a commercially available workstation, end-diastolic- (EDV), end-systolic- (ESV), stroke volume (SV), ejection fraction (EF) and myocardial mass (MM) were calculated from MSCT (temporal resolution 105 - 210 ms) data according to the modified Simpson's rule and compared to MRI (1.5 T scanner, temporal resolution 48 ms) using a 2D TrueFISP cine sequence with respiration hold. RESULTS: In all cases, the quality was adequate for both MSCT and MRI. MSCT and MRI had an excellent correlation for EDV (r = 0.86), ESV (r = 0.91), EF (r = 0.87) and MM (r = 0.88), and a good correlation for SV (r = 0.70). The mean difference was 13.2 +/- 21.9 ml for EDV, 8.7 +/- 15.9 ml for ESV, 4.6 +/- 12.3 ml for SV, 1.4 +/- 5.2 % for EF, and 11.9 +/- 13.8 g for MM. However, EDV (p = 0.002), ESV (p = 0.005), SV (p = 0.048), and MM (p < 0.0001) were significantly overestimated with MSCT compared to MRI. For EF, no significant difference between MSCT and MRI was found (p = 0.15). CONCLUSION: For left ventricular functional parameters, MSCT of the heart with retrospective ECG-gating showed a high correlation with MRI, which has an important implication when using MSCT for non-invasive cardiac imaging. Despite the high correlation, overestimation of EDV, EVS, SV, and MM with MSCT has to be taken into account when applying this technology in clinical practice. EF was not significantly different between both modalities.

Multislice CT in cardiac and coronary angiography.

In the last 2 years, mechanical multidetector-row CT (MDCT) systems with simultaneous acquisition of four slices and a half second scanner rotation time have become widely available. Data acquisition with these scanners allows for considerably faster coverage of the heart volume compared with single slice scanning. This increased scan speed can be used for retrospective gating together with 1 mm collimated slice widths and allows coverage of the entire cardiac volume in one breath-hold. First results from studies in correlation with intracoronary ultrasound suggest that MDCT technology not only offers the possibility to visualize intracoronary stenoses non-invasively, but also to differentiate plaque morphology. This is especially the case with the next generation of 16-row MDCT systems. An increased number of simultaneously acquired slices and submillimetre collimation for cardiac applications allows true isotropic scanning with high temporal resolution. Contrast-enhanced MDCT is a promising non-invasive technique for the detection, visualization and characterization of stenotic artery disease. It could act as a gatekeeper prior to cardiac catherization and finally replace conventional diagnostic modalities.

Non-invasive evaluation of atherosclerosis with contrast enhanced 16 slice spiral computed tomography: results of ex vivo investigations.

OBJECTIVE: To evaluate the diagnostic accuracy of 16 slice computed tomography (CT) in determining plaque morphology and composition in an experimental setting. The results were compared with histopathological analysis as the reference standard. METHODS: Nine human popliteal arteries derived from amputations because of atherosclerotic disease were investigated with multislice spiral CT (MSCT). Atherosclerotic lesions were morphologically classified (completely or partially occlusive, concentric, eccentric), and tissue densities were determined within these plaques. In addition, vessel dimensions were quantitatively measured. RESULTS: The results were compared with histological analysis. The concordance index kappa for morphological classification was 0.88. Plaque density (n = 51 lesions) was significantly different (p < 0.0001) between lipid rich, fibrotic, and calcified lesions (Stary stage III: n = 2, 58 (8) Hounsfield units (HU); Stary V: n = 11, 50 (21) HU; Stary VI: n = 14, 96 (42) HU; Stary VII: n = 6, 858 (263) HU; Stary VIII: n = 18, 126 (99) HU). The concordance index kappa for the classification of plaques based on density was 0.51. Vessel dimensions had a good correlation (r = 0.98). CONCLUSIONS: 16 slice CT was found to be a reliable non-invasive imaging technique for assessing atherosclerotic plaque morphology and composition. Although calcified lesions can be differentiated from non-calcified lesions, the diagnostic accuracy in further subclassifying non-calcified plaques as lipid rich and fibrotic is low, even under experimental conditions.

[Left ventricular functional parameters using ECG-gated multidetector spiral CT in comparison with invasive ventriculography]. / Bestimmung linksventrikulärer Funktionsparameter mittels EKG-gesteuerter Mehrschicht-Computertomographie im Vergleich mit der invasiven Ventrikulographie.

PURPOSE: To evaluate the accuracy of left ventricular function using a multidetector CT (MDCT) with retrospective ECG-gating and to compare the results with conventional ventriculography. MATERIALS AND METHODS: In 26 patients, retrospectively ECG-gated MDCT of the heart (Volume Zoom, Siemens, Germany) as well as conventional coronary angiography including ventriculography was performed to exclude or follow coronary artery disease. CT examination (120 KV, 400 mAs) was carried out with 4 x 1 mm collimation (500 ms gantry rotation time). For CT angiography, 150 ml of contrast media was injected intravenously at a flow rate of 4 ml/s. All data sets of the functional cardiac parameters were reconstructed in end-systolic and end-diastolic phase. End-systolic volume (ESV), end-diastolic volume (EDV) and ejection fraction (EF) were determined from multiplanar reformations orthogonally through the cardiac short axis and analyzed using special evaluation software (ARGUS, Siemens). The results were compared with ESV, EDV and EF obtained from invasive ventriculography. RESULTS: In all cases, a sufficient quality of the MDCT images was achieved. EDV (150.1 +/- 16.2 ml MDCT vs. 138.7 +/- 16.9 ml ventriculography; mean difference 11.4 +/- 12.7 ml; r = 0.51) had an acceptable correlation to conventional ventriculography, and ESV (58.1 +/- 14.6 ml vs. 50.2 +/- 13.4 ml; mean difference 7.9 +/- 8.8 ml; r = 0.81) and EF (60.9 +/- 13.6 % vs. 64.9 +/- 12.7 %; mean difference 4.0 +/- 6.2 %; r = 0.79) showed a good correlation. In comparison with invasive ventriculography, MDCT tended to overestimate significantly EDV (p = 0.008) and ESV (p = 0.003) and to underestimate EF (p = 0.001). CONCLUSION: MDCT of the heart with retrospective ECG-gating enables efficient estimation of left ventricular function, providing important additional information of non-invasive cardiac imaging using MDCT. However, EDV and EVS were significantly overestimated and EF was underestimated in MDCT compared to ventriculography.

Assessment of peripheral arterial occlusive disease: comparison of multislice-CT angiography (MS-CTA) and intraarterial digital subtraction angiography (IA-DSA).

PURPOSE: The aim of the study was to assess the arterial vascular system of the lower extremities in patients with peripheral arterial occlusive disease using Multislice-CT angiography (MS-CTA) and to compare the results with the standard of reference, intraarterial digital subtraction angiography (IA-DSA). MATERIALS AND METHODS: MS-CTA and IA-DSA of the lower extremities were carried out on 23 patients with peripheral arterial occlusive disease (Fontain Stage IIb: 18, III: 3, IV: 2). MS-CTA comprised a 4 x 2.5 mm collimation, 15 mm table feed/rotation, 0.5 sec rotation time and 3 mm slice thickness (1.5 mm reconstruction increment). Delay time was determined by bolus tracking. 150 ml of contrast media were injected intravenously at a flow rate of 3 ml/sec. Maximum intensity projection (MIP) reformations were performed using a semi-automatic vessel tracking program. MS-CTA (axial and MIP-reformatted images) and IA-DSA were reviewed by two radiologists. The grade of vascular stenosis as well as occlusion were rated on a scale of 0 to 3 (0=0-50% stenosis, 1 = 51-75% stenosis, 2 = 76-99% stenosis, 3 = occlusion). RESULTS: For MS-CTA, the mean delay time was 30.2 s (23-40 s), mean scan time was 37.4 (33-42 s). Data analysis was based upon a total of 1136 vascular segments for both methods (568 each). A comparison of all the evaluated segments in both techniques revealed a MS-CTA / IA-DSA 86.3% match. Out of 442 segments proximal the trifurcation, 386 were correctly assessed in MS-CTA (87.3%) and distal the trifurcation, 101 out of 126 segments were rated correctly (80.2%). In MS-CTA, an overall confidence interval of 95% can be achieved in 83.2% to 89.0% for correctly rated stenosis grading. CONCLUSIONS: In patients with peripheral arterial occlusive disease, MS-CTA of the lower extremity is a promising minimal-invasive method for detection of relevant arterial stenoses. However, the technique was limited to routine diagnostic purposes due to severe calcifications and time consuming reconstruction procedures.