Our objective was to evaluate the image quality of a 16-slice CT system with a rotation time of 375 ms in the assessment of coronary arteries. One hundred patients underwent iodine-enhanced CT coronary angiography within a single breath hold. Images were reconstructed in diastole, 300, 350, 400, 450, 500 and 550 ms prior to the onset of the next R-wave using absolute reverse retrospective ECG gating. The 15 coronary segments of the AHA classification were consensually reviewed by two radiologists. On the whole, best quality imaging was obtained with reconstruction intervals of -350 ms and -400 ms in high percentages of each segment (P<0.0001). Only 6.2% of the arteries with a diameter greater than or equal to 1.5 mm were not assessable because of extensive calcifications (3.9%), cardiac motion artifacts (1.9%), lack of enhancement (0.2%) and stent artifacts (0.3%). In patients with a heart rate above 70 beats per minute, the percentage of assessable segments decreased to 88%, while at a lower heart rate it increased to 95%. In 61% of the patients, all segments were assessable. In conclusion, this generation of CT technique may allow visualization of coronary arteries with a low percentage of non-assessable segments.

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Twenty-three patients who had undergone aortic valve replacement with a mechanical aortic valve prosthesis (ball-valve: 17, tilting-disc: 6) were investigated by retrograde left ventricular catheterization using a 6 F pigtail catheter. Twelve of these 23 patients also had had combined aortic and mitral valve replacement. To assess the magnitude of the catheter-induced aortic regurgitation and its effect on left ventricular and mitral valve function, 10 patients (group 1) were simultaneously investigated by the transseptal route (8 patients) or direct left ventricular puncture. The 13 other patients (group 2) were studied only by the retrograde crossing of the aortic valve prosthesis. In group 1, placement of the catheter across the valve induced an increase in heart rate (+12%), in left ventricular end-diastolic pressure (from 17.2 +/- 9.6 to 33.3 +/- 12.0 mmHg), a decrease in aortic systolic (-19%) and diastolic (-25%) pressures, and left ventricular systolic pressure (-10%). Transvalvular aortic pressure gradient increased from 15.4 +/- 8.2 to 23 +/- 12.1 mmHg. Pre- and post-crossing pressure gradients were linearly correlated (r = 0.93). Left ventricular end-diastolic volume increased slightly but significantly (+9%), ejection fraction remained unchanged. Pre- and post-crossing regurgitation fractions were linearly related (r = 0.98). Hence, the magnitude of catheter-induced aortic regurgitation averaged 27% whether or not a pre-crossing regurgitation was noted. In group 2, retrograde crossing of the aortic valve prosthesis induced similar hemodynamic changes. There were no catheterization-related complications.(ABSTRACT TRUNCATED AT 250 WORDS)

A 53-year-old male was admitted for typical acute chest pain. The ECG showed a mirror image of posterior myocardial ischemia. Initial biology was normal but cardiac markers (creatine kinase and troponin) rose later. Echocardiography did not reveal any hypokinetic myocardial segment. There was no left ventricular dysfunction or valvular disease. There was no pericardial effusion or aortic dissection image. This patient was treated as a "non-ST segment elevation myocardial infarction" (NSTEMI), also called subendocardial myocardial infarction. A selective coronary angiography (SCA) was performed the next day and after careful examination by several experts, no coronary lesion was detected. Left ventriculography was also normal. Cardiac MRI was then performed and revealed a late focal subendocardial enhancement, located in the mid infero-posterior myocardial segment (Fig. A, arrow). This lesion appeared to be ischemic, despite normal SCA. Computed tomography coronary angiography (CTCA) was finally done, showing a hypodense image, with also an ischemic aspect, in the same subendocardial area (Fig. B, arrow) as observed on MRI. Furthermore, CTCA detected tight luminal narrowing with hypodense material (soft atheroma or clot) in a circumflex branch (Fig. C, arrow), corresponding to the suspected ischemic territory. In this case, CTCA both confirmed ischemic etiology and identified culprit artery missed by SCA. CommentSCA is the gold standard for investigating coronary arteries. This invasive technique gives precise information about coronary stenosis and can be immediately extended to a therapeutic approach if necessary. However, SCA can miss diagnosis in some cases such as ostial stenosis of the left main trunk, abnormal coronary origin or as demonstrated