[Dual-source CT in chest pain diagnosis]. / Dual-source-CT in der Diagnostik des Thoraxschmerzes.

BACKGROUND: With the depiction of pulmonary arteries, coronary arteries, and the aorta, CT angiography of the chest offers a comprehensive diagnostic work-up of unclear chest pain. The aim of this study was to assess the diagnostic accuracy of dual-source CT in this patient group. MATERIALS AND METHODS: A total of 47 patients suffering from unclear chest pain were examined with a Siemens Somatom Definition. Volume and flow of contrast media (Ultravist, Schering) were adapted to the body weight. The examinations were evaluated with regard to image quality and contrast opacification and to the diagnostic accuracy with reference to the final clinical diagnosis. RESULTS: Adequate contrast opacification was achieved in all examinations. The depiction of the coronary arteries was diagnostic in all cases. The cause of chest pain could be identified in 41 cases. Among the diagnoses were coronary and myocardial pathologies, valvular disease, aortic aneurysms and dissections, pulmonary embolism, and pneumonic consolidation. CONCLUSION: DSCT angiography of the chest offers a very good image quality even at high heart rates so that a high diagnostic accuracy is achieved in patients with acute chest pain.

Combined use of 64-slice computed tomography angiography and gated myocardial perfusion SPECT for the detection of functionally relevant coronary artery stenoses. First results in a clinical setting concerning patients with stable angina.

AIM: In patients with stable angina pectoris both morphological and functional information about the coronary artery tree should be present before revascularization therapy is performed. High accuracy was shown for spiral computed tomography (MDCT) angiography acquired with a 64-slice CT scanner compared to invasive coronary angiography (ICA) in detecting "obstructive" coronary artery disease (CAD). Gated myocardial SPECT (MPI) is an established method for the noninvasive assessment of functional significance of coronary stenoses. Aim of the study was to evaluate the combination of 64-slice CT angiography plus MPI in comparison to ICA plus MPI in the detection of hemodynamically relevant coronary artery stenoses in a clinical setting. PATIENTS, METHODS: 30 patients (63 +/- 10.8 years, 23 men) with stable angina (21 with suspected, 9 with known CAD) were investigated. MPI, 64-slice CT angiography and ICA were performed, reversible and fixed perfusion defects were allocated to determining lesions separately for MDCT angiography and ICA. The combination of MDCT angiography plus MPI was compared to the results of ICA plus MPI. RESULTS: Sensitivity, specificity, negative and positive predictive value for the combination of MDCT angiography plus MPI was 85%, 97%, 98% and 79%, respectively, on a vessel-based and 93%, 87%, 93% and 88%, respectively, on a patient-based level. 19 coronary arteries with stenoses > or =50% in both ICA and MDCT angiography showed no ischemia in MPI. CONCLUSION: The combination of 64-slice CT angiography and gated myocardial SPECT enabled a comprehensive non-invasive view of the anatomical and functional status of the coronary artery tree.

[Quantification of coronary artery stenoses: comparison of 64-slice and dual source CT angiography with cardiac catheterization]. / Quantifizierung von Stenosen der Koronararterien: 64-Zeilen-CT-Angiographie und Dual Source vs. Herzkatheter.

BACKGROUND: Until now stenoses of the coronary arteries have been evaluated visually with CT angiography. Therefore, the results were highly dependent on subjective factors inherent in the examiner. New software tools for semiquantitative analysis (CT-QCA, quantitative coronary assessment) might be adequate to improve the diagnostic accuracy und reproducibility. MATERIAL AND METHODS: CTAs of 20 patients were analyzed. Ten patients each were evaluated using 64-slice CT (64SCT) and dual source CT (DSCT) (Somatom Sensation 64 and Somatom Definition, Siemens Medical Solutions, Forchheim), respectively. Two radiologists independently evaluated the data visually and with the help of a software tool (Syngo Circulation, Siemens Medical Solutions, Forchheim). The results of the quantitative assessment of the invasive heart catheterization served as the reference standard. Sensitivity and specificity as well as the correlation coefficient, the systematic error, and the interobserver agreement (kappa) were determined. RESULTS: In each of both patient groups 12 stenoses were detected. For the detection of stenoses >75%, sensitivity and specificity for the visual evaluation using the 64SCT were 100% and 90%, and with the CT-QCA both were 100%. For the DSCT sensitivity and specificity were 100% for both the visual and semiautomated evaluation. The Bland-Altman plot of the results of the 64SCT showed an overestimation of 3.3% (+/-62.7%/56.2%) compared to the heart catheterization. The results of the DSCT exhibited an overestimation of 6.2% (+/-33.1%/19.8%). The interobserver agreement of the CT-QCA and the visual evaluation showed a kappa value of 0.75 and for DSCT of 1.0. CONCLUSION: The results showed a good correlation of grading stenosis between the software-assisted evaluation and the results of the coronary catheter angiography. The promising results of the DSCT are due to a superior temporal resolution compared to the 64SCT. Confirmation of these data by trials in larger patient collectives is warranted.

[Prediction of serious cardiovascular events by determining coronary artery calcification measured by multi-slice computed tomography]. / Prädiktion kardiovaskulärer Ereignisse durch Koronarkalkbestimmung mit der Mehrzeilen-Computertomographie.

BACKGROUND: The efficacious prophylaxis of myocardial infarction requires an accurate identification of patients at risk. Conventional risk stratification is often insufficient for this. We therefore examined the predictive value of coronary calcifications for future cardiovascular events. METHODS: We determined the extent of coronary calcification by multi-slice computed tomography in 924 patients (443 men, 481 women, aged 59.4 +/- 18.7 years) after coronary artery disease had been excluded by coronary angiography. To quantify coronary calcifications the volume score was calculated. After an observation period of 36 months was calculated the incidence of coronary revascularisation, myocardial infarction, and cardiac death. RESULTS: During the observation period the event rates for coronary revascularization (5.4 %/ year vs. 2.9 %/ year), myocardial infarction (3.8 %/ year vs. 1.8 %/ year), and cardiac death (2.1 %/ year vs. 1.0 %/ year) in patients with volume scores above the 75th percentile were significantly higher compared to the total study group. Correspondingly the scores in patients with revascularization (397 +/- 187), myocardial infarction (412 +/- 176), and cardiac death (422 +/- 184) were significantly higher compared to patients without cardiovascular events (218 +/- 167). In addition future cardiovascular events were excluded in patients without coronary calcifications. CONCLUSIONS: By determining coronary calcifications it was possible to identify patients at risk for myocardial infarction could be identified. Future cardiovascular events could not be observed in patients without coronary calcifications.

Coronary calcification in long-term type 1 diabetic patients -- a study with multi slice spiral computed tomography.

The risk for cardiovascular disease in diabetes is excessive. Multislice spiral computed tomography (MSCT) is a new technique for the assessment of coronary calcification in coronary artery disease. The aim of the study was to evaluate the presence of coronary calcium in asymptomatic long-term type 1 diabetic patients. Seventy-one type 1 diabetic patients (age 48 +/- 9 y, HbA1c 7.7 +/- 1.2, BMI 24.4 +/- 2.8, duration of diabetes 26 +/- 9 y) without clinical evidence for coronary artery disease were assessed with MSCT. A volumetric score was used to calculate the coronary calcification (CC) score. Five cardiac reflex tests were performed to study patients for cardiac autonomic neuropathy. Coronary calcifications were detectable in 22 (31 %) type 1 diabetic patients (CC-score > 0, mean CC-score 174 +/- 228 [X+/-SD]). Fourty-nine (69 %) type 1 diabetic patients demonstrated no coronary calcifications (CC-score= 0). In patients with coronary calcifications, both cardiac autonomic neuropathy and retinopathy were detected more frequently than in those without (64 % vs. 29 %, p < 0.02; 59 % vs. 31 %; p < 0.02). Duration of diabetes was longer in patients with than without coronary calcification (32 +/- 10 y vs. 24 +/- 8 y, p < 0.01). Age, BMI, and HbA1c were not significantly different between patients with and without coronary calcification. The study demonstrates that nearly one third of asymptomatic long-term type 1 diabetic patients present with coronary calcifications. In the patients, there is evidence for an association between coronary calcification and both cardiac autonomic neuropathy and retinopathy. MSCT is a promising non-invasive approach to analyze early alterations of the coronary system in diabetic patients.

[ECG-gated bypass CT angiography--application in imaging arterial bypasses]. / EKG-gesteuerte Bypass-CT-Angiographie--Einsatz in der Darstellung arterieller Bypässe.

Nowadays coronary artery bypass grafting is increasingly performed using arterial grafts. Purpose of the study was the evaluation of a appropriate 16 detector-row CT angiography protocol in patients after predominantly arterial bypass grafting. Fourteen patients after bypass grafting were including into the study and CT angiography carried out in the early postoperative period using a 16 detector-row CT system. To reduce cardiac pulsation artifacts data acquisition was implemented using ECG-gating algorithms. Overall 43 grafts (37 arterial, 6 venous) were examined. In 13 patients surgery had been performed using composite grafts with T or TY configuration. The mean heart rate was 74.1 bpm and showed a negative correlation to the image quality (r=-0.65; p=0.01). However, all data sets were diagnostic. Contrast injection protocol allowed for a homogeneous opacification throughout the vessels of interest. All non-delineationable grafts (5) showed a close proximity to the heart (T or Y grafts). Cardiac surgery is increasingly focusing on arterial revascularisation in bypass grafting and therefore leading to new demands for non-invasive bypass graft imaging. 16 detector-row CT allows a reliable visualization of even composite arterial grafts. However, for detection of grafts in the proximity of the heart a reduction of the heart rate (<65-70) still seems to be necessary.

[Technique and possibilities of cardiac computed tomography]. / Kardiale Mehrzeilen-Computertomographie. Koronarangiographie--ein Auslaufmodell?

Electron beam computed tomography no longer has a role to play in Germany. In contrast, multidetector spiral CT has great potential for replacing some coronary catheter studies, in particular for the exclusion of coronary artery disease, and this in particular since the forthcoming introduction of a 64-slice MDCT scanner promises a further improvement in temporal and special resolution. Currently, however it is no alternative to invasive angiography, since quantification of coronary stenoses is not possible; nor can a diagnostic evaluation be made in the presence of coronary calcifications or intracoronary stents. In particular, however, before applying CT angiography to the heart, the patient groups that can benefit from this method must be defined, especially in light of the fact that radiation exposure is three times as high as with diagnostic coronary catheterization.

[Coronary calcifications and the diagnosis of coronary artery disease]. / Screeningmethode bei asymptomatischen Risikopatienten. Kalkscore als früher Marker der Koronarsklerose.

Coronary calcium is a sensitive marker of coronary atherosclerosis, even at an early stage. With the aid of multislice computed tomography, noninvasive visualization of the microcalcification is possible. This enables the identification of asymptomatic patients at risk of developing future cardiovascular disease, and the initiation of effective preventive measures. In addition, in symptomatic patients, CT angiography with calcium scoring is of high negative predictive value in the exclusion of coronary artery disease.

[Detection and characterization of atherosclerotic coronary plaques with multislice spiral computed tomography]. / Kardiale Risikostratifizierung: Den atherosklerotischen Plaque im Blick.

Provided that adequate image quality is achieved, contrast-enhanced multislice spiral computed tomography enables the identification and characterisation of calcified and non-calcified coronary plaques. This is a major advance in the non-invasive assessment of coronary atherosclerosis that promises to open up new opportunities for a better understanding and risk stratification of this condition, with visualization of non-calcified hypodense lesions in particular appearing to be of prognostic importance. Current limitations of the technique relating mainly to temporal and spatial resolution may be eliminated by the introduction of a new generation of scanners enabling 64 slices and more.

Non-invasive intravenous coronary angiography using electron beam tomography and multislice computed tomography.

BACKGROUND: Electron beam computed tomography (EBCT) and multislice computed tomography (MSCT) are both suitable for non-invasive identification of coronary stenoses. OBJECTIVE: To compare intravenous coronary EBCT angiography (EBCTA) and MSCT angiography (MSCTA) with regard to image quality and diagnostic accuracy. METHODS: EBCTA was done using an Imatron C-150 XP scanner in 101 patients following a standard protocol (slice thickness 3 mm, overlap 1 mm, acquisition time 100 ms, prospective ECG trigger). For MSCTA in a different set of 91 patients (using a Siemens Somatom Plus4VZ scanner), the whole volume of the heart was covered in a spiral technique by four simultaneous detector rows. Using retrospective ECG gating, the raw data were reconstructed in (mean (SD)) 215 (12) axial slices acquired in diastole (slice thickness 1.25 mm, overlap 0.5 mm, acquisition time 250 ms/slice). RESULTS: With EBCTA, 76% of predetermined coronary segments in a nine segment model could be assessed with diagnostic image quality, and with MSCTA, 82%. A low contrast to noise ratio with EBCTA, and the presence of motion artefacts with MSCTA were the main reasons for inadequate image quality. Using conventional angiography as the gold standard, 77% of stenoses of > 50% could be identified correctly with EBCTA and 82% with MSCTA. Significant stenoses were correctly ruled out in 93% of segments with EBCTA, and in 96% of segments with MSCTA. The average contrast to noise ratio was higher with MSCTA than with EBCTA (9.4 v 6.5; p < 0.001). CONCLUSIONS: EBCTA and MSCTA show similarly high levels of accuracy for determining and ruling out significant coronary artery stenoses. MSCTA is capable of providing good image quality in more coronary segments than EBCTA because of its better contrast to noise ratio and higher spatial resolution. Motion artefacts seen at heart rates of > 75 beats/min and a higher radiation exposure are the main limitations of MSCTA.

[Detection of coronary calcinosis with multislice spiral computerized tomography: an alternative to electron beam tomography]. / Detektion von Koronarkalk mit der Mehrschicht-Spiral-Computertomographie: Eine Alternative zur Elektronenstrahltomographie.

Electron-beam CT (EBT) has been used for years as the gold standard to quantify coronary artery calcification as a marker of coronary atherosclerosis. With the introduction of Multi-Slice Spiral CT (MSCT) technology in 1999, EBT is now challenged in the determination of coronary calcium. The aim of this study was to determine the diagnostic accuracy of MSCT for the assessment of coronary calcium, comparing this new technique to EBT. The study population consisted of 54 male patients, aged 58 +/- 11 years with suspected coronary artery disease. For EBT, 40 axial slices (scan time = 100 ms, slice thickness = 3 mm) were acquired in one breath-hold (35 +/- 5 s) using an ECG-trigger at 80% of the RR interval. For MSCT, simultaneous acquisition of four axial slices (scan time = 250 ms, slice thickness = 2.5 mm) allowed the entire heart (40 slices) to be covered in one breath-hold (25 +/- 5 s) using a prospective ECG-trigger (R--450 ms). For quantification of coronary calcium the Agatston and the Volumetric calcium score (VCS) were applied. Mean Agatston score of the study group was calculated as 88 +/- 111 (median = 45), which is between the 25th and 75th age-corrected percentile of asymptomatic patients. For the Volumetric calcium score, number of lesions, calcium mass and density, no statistical difference was found between both imaging modalities. Agatston and Volumetric calcium score were statistically different between and within both scans. Mean variability of VCS of the two methods was calculated as 24% and was in the range of repeated EBT studies (14-44.9%). The Multi-Slice Spiral CT scanner is equivalent to EBT for the determination of coronary calcium and can, therefore, be used for calcium screening. Using a prospective ECG-trigger technique, the application of the Agatston method delivers statistically different results in comparison to EBT. With the application of the spiral mode technique, retrospective ECG-trigger and thinner slice thickness, further improvement in variability can be expected, thus allowing for follow-up studies to determine progression or regression of atherosclerosis with high accuracy.

[CT angiography of the coronary arteries with a 16-row spiral tomograph. Effect of spatial resolution on image quality]. / CT-Angiographie der Koronararterien mit einem 16-Mehrzeilen-Spiral-CT Einfluss der räumlichen Auflösung auf die Bildqualität.

PURPOSE: To evaluate image quality of coronary CT angiography with retrospectively ECG-gated 16 multi-slice spiral CT (MSCT), reconstructed with 0.75 mm slice thickness for optimal spatial resolution and with 1.3 mm slice thickness, to produce spatial resolution comparable to a 4-MSCT. MATERIALS AND METHODS: Ten patients underwent coronary CT angiography with a 16-MSCT (Siemens Sensation 16, Forchheim, Germany) with 0.75 mm detector collimation. Raw helical CT data were retrospectively reconstructed using two different settings. Setting A: B20f smooth kernel, axial MPR with 1.3 mm slice thickness and 0.7 mm increment. Setting B: B35f "HeartView" medium-smooth kernel, 0.75 mm slice thickness, 0.5 mm increment. In the axial slices two regions of interest (ROIs) were placed in the area of the aortic root (AR) and more caudal in the area of the left ventricle (LV). Image noise was determined by the standard deviation of the CT numbers.Two readers determined visibility of coronary arteries by standardized maximum intensity projections (MIP) post-processing in left, right anterior and left anterior oblique projection plane from setting A and B. Each projection was rated on a five point rating scale concerning plaque delineation. Points determined for each data set were summed up and used for comparison. RESULTS: No significant difference between the CT-numbers was found for setting A and B (A: 283.0 in AR/295.9 in LV and B: 282,9 in AR/297.2 in LV; p >0.2). However, the image noise was significantly different for setting A and B (A: 4.46 in AR/1.67 in LV and B: 8.16 in AR/7.38 in LV; p <0.01). Better delineation of the coronary arteries and atherosclerotic lesions could be achieved from MIP projections in setting B compared to setting A. CONCLUSION: Higher image noise is present in coronary 16-MSCT with thin-slice reconstruction compared to simulated 4-MSCT. However the MIP-reconstructions benefit most from the higher spatial resolution.

Reproducibility of coronary calcium quantification in repeat examinations with retrospectively ECG-gated multisection spiral CT.

High reproducibility is a key requirement for coronary calcium scoring in follow-up examinations. We investigated the inter-examination reproducibility of calcium scoring with retrospectively ECG-gated multisection spiral CT (MSCT). Fifty patients were examined twice with MSCT. Slices were reconstructed with retrospective ECG gating in the diastolic phase with 3-mm slice width and up to 125-ms temporal resolution. We calculated the Agatston score, calcium volume with and without isotropic interpolation, and calcium mass, and derived the mean and median variability. We investigated the change of variability with use of 3-mm non-overlapping and overlapping increments (2, 1.5, 1 mm). Use of overlapping increment results in considerably reduced interscan variability. We observed a minimum mean variability of 12% and a minimum median variability of 9% for the Agatston score. For volume and mass quantification we obtained a minimum mean variability of 7.5% and a minimum median variability of 5%. Multisection spiral CT enables coronary calcium quantification with high reproducibility in follow-up examinations mainly founded on image data with reduced partial-volume errors due to overlapping increment.

Pressure-guided nonsurgical myocardial reduction induced by small septal infarctions in hypertrophic obstructive cardiomyopathy.

OBJECTIVES: We sought to assess the safety and efficacy of pressure-guided nonsurgical myocardial reduction (NSMR) with the induction of small septal infarctions in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Nonsurgical myocardial reduction has been shown to decrease left ventricular outflow tract (LVOT) obstruction and to improve symptoms in patients with HOCM. Infarct sizes differ considerably among studies published so far. METHODS: In 50 patients, the LVOT gradient was invasively determined at the time of the intervention, four to six months (n = 49) and 12 to 18 months (n = 25) after NSMR. New York Heart Association functional class and quality of life were assessed by using a standard questionnaire. Exercise capacity was tested by spiro-ergometry. Left ventricular (LV) mass was determined by electron beam computed tomography. RESULTS: Small septal infarctions (mean creatine kinase value 413 +/- 193 U/l) resulted in a sustained decrease in LVOT gradients, from 80 +/- 33 to 18 +/- 17 mm Hg after four to six months (p < 0.001, n = 49) and to 17 +/- 15 mm Hg (p < 0.001, n = 25) after 12 to 18 months. Nonsurgical myocardial reduction was followed by a decrease in LV hypertrophy, which was associated with a sustained increase in exercise capacity, as well as improvement in quality of life. CONCLUSIONS: Pressure-guided NSMR inducing small septal infarctions was sufficient to result in a sustained decrease in LVOT obstruction and to improve symptoms. The incidence of complications, such as complete heart block with necessary permanent pacemaker implantation (<10%), seems to be diminished by minimizing the infarct size.

ECG-gated reconstructed multi-detector row CT coronary angiography: effect of varying trigger delay on image quality.

PURPOSE: To evaluate the effectiveness of electrocardiographically (ECG)-gated retrospective image reconstruction for multi-detector row computed tomographic (CT) coronary angiography in reducing cardiac motion artifacts and to evaluate the influence of heart rate on cardiac image quality. MATERIALS AND METHODS: Sixty-five patients with different heart rates underwent coronary CT angiography. Raw helical CT data and ECG tracings were combined to retrospectively reconstruct at the defined consecutive z position with a temporal resolution of 250 msec per section. The starting points of the reconstruction were chosen between 30% and 80% of the R-R intervals. The relationships between heart rate, trigger delay, and image quality were analyzed. RESULTS: Optimal image quality was achieved with a 50% trigger delay for the right coronary artery and 60% for the left circumflex coronary artery. Optimal image quality for the left anterior descending coronary artery was equally obtained at 50% and 60% triggering. A significant negative correlation was observed between heart rate and image quality (P <.05). The best image quality was achieved when the heart rate was less than 74.5 beats per minute. CONCLUSION: To achieve high image quality, the heart rate should be sufficiently slow. Selection of appropriate trigger delays and a decreasing heart rate are effective to reduce cardiac motion artifacts.

Usefulness of calcium scoring using electron beam computed tomography and noninvasive coronary angiography in patients with suspected coronary artery disease.

The aim of this study was to investigate the reliability of calcium scoring (CS) and electron beam computed tomographic angiography (EBCTA) as a noninvasive tool in the diagnosis of coronary artery disease (CAD): 93 consecutive patients (aged 59 +/- 9 years) with symptoms suspicious for CAD underwent CS. In 87 of these subjects, an additional EBCTA investigation was performed. Using receiver-operating characteristic curve analysis, we determined a calcium score cut point providing an overall sensitivity of 80% and a specificity of 72% in detecting patients with CAD. For clinical purposes the use of cut points is difficult. We therefore determined score ranges providing >80% specificity (high score range) and >85% sensitivity (low score range) and determined the scores between these ranges as equivocal borderline scores. Calculated on a per-segment basis in assessable proximal and midcoronary segments, the sensitivity for detecting coronary stenoses >50% was 78%, and the specificity was 93%. Thus, 32 of 44 patients with significant CAD and 24 of 49 patients without CAD were correctly classified. The combination of CS and EBCTA predicted CAD in 77% (72 of 93) of patients. No or low calcium scores provided high specificity for ruling out CAD. The addition of EBCTA in those patients improved sensitivity. In patients with high calcium scores, accuracy of EBCTA was not significantly different from CS alone (72% vs 83%), whereas in patients with borderline scores it was significantly superior (80% vs 58%, p <0.03). Thus, the complementary use of CS and EBCTA appears beneficial, particularly in patients with borderline scores, and could improve sensitivity in the low score range. In the presence of high scores, no major diagnostic gain from an additional EBCTA versus CS alone could be observed.

Navigator echo-based respiratory gating for three-dimensional MR coronary angiography: reduction of scan time using a slice interpolation technique.

PURPOSE: The aim of the study was to compare a conventional respiratory-gated 3D MR coronary angiographic technique (conventional MRCA) with a respiratory-gated 3D MR coronary angiographic technique that includes a slice interpolation technique (slice interpolation MRCA). Both MRCA techniques were compared based on the quality of visualization of the coronary arteries and the diagnostic accuracy in identifying hemodynamically significant coronary artery stenoses. METHOD: Forty patients with known proximal coronary artery stenosis after conventional CA were examined on a 1.5 T scanner, that is, 20 patients with each sequence. A 6 point grading system (0 = worst quality, 5 = best quality) was used to evaluate and compare the image quality. The length and proximal diameter of the depicted coronary arteries were measured. Detection of coronary artery stenoses was compared with that obtained by conventional CA by two blinded readers. RESULTS: With the slice interpolation technique, the average scan time of the entire heart was reduced by approximately 40%. With use of conventional MRCA, 69% of all proximal and middle coronary artery segments were visualized with a sufficient image quality; with the slice interpolation technique, 79% of these segments were depicted adequately. For the assessment of stenoses, sensitivity was 71% and specificity was 53% for conventional MRCA and 72 and 60% for slice interpolation MRCA, respectively. These differences in sensitivity and specificity were statistically not significant. CONCLUSION: The application of a slice interpolation technique reduces the scan time, maintains a comparable sensitivity and specificity for the assessment of coronary artery stenoses, and increases the number of completely identified coronary artery segments compared with the conventional technique.

[Angiography with multi-slice spiral CT. Detecting plaque, before it causes symptoms]. / Angiographie mit dem Mehrschicht-Spiral-CT. Plaques erkennen, bevor sie Beschwerden machen.

The short imaging time of 1/4 second, renders the new generation of multiple-slice spiral CT devices with ECG gating enables the investigation of the heart without disturbing motion artefacts. With this method, calcifications of the coronary arteries can be detected or excluded. Certain amounts of coronary "chalk" in asymptomatic patients with risk factors point to coronary artery disease and thus a need to modulate the risk factors. With the aid of intravenous injection of contrast medium during the examination, non-calcified plaques in the coronary arteries can also be visualized. A limiting factor is that the patient's heart rate should not exceed 60 beats per minute. Indications for this examination are visualization of coronary vessels with the aim of excluding coronary artery disease, pre-operative planning and monitoring of bypass vessels, and non-invasive follow-up after PTCA and stenting.

Coronary artery calcium measurement: agreement of multirow detector and electron beam CT.

OBJECTIVE: The purpose of our study was to establish the most suitable algorithm to compare coronary artery calcium measurements performed with electron beam CT and multirow detector CT for the assessment of coronary artery disease. SUBJECTS AND METHODS: Coronary artery screening was performed in 100 patients with both electron beam and multirow detector CT. The images were transferred to a dedicated workstation for determination of the calcium score, volume, mass, density, and number of lesions. In addition to the traditional threshold of 130 H, the score of multirow detector CT studies was reevaluated at a threshold of 90 H. Fifty-nine of the patients underwent conventional coronary catheterization. Receiver operating characteristic curve analysis of the different scoring algorithms for detection of significant coronary artery stenosis was performed. RESULTS: The correlation between electron beam CT and multirow detector CT was high for every quantification algorithm. Determination of the score and the number of lesions with multirow detector CT revealed a systematic error of the measurement compared with electron beam CT. The areas under the curve in the receiver operating characteristic curve analyses for electron beam and multirow detector CT were similar for the score, volume, and mass, whereas they were lower for the density. No significant difference was found for the areas under the curve between scores using a 130-H and those using a 90-H threshold. CONCLUSION: Volume and mass indexes are superior to the traditional score, density, and number of lesions for comparing the results of electron beam and multirow detector CT and for determining significant coronary artery disease.