Cardiac CT & MRI Literature

A Pictorial Review of Coronary Artery Bypass Grafts at Multidetector Row CT -- Marano et al. 127 (4): 1371 -- Chest

This article by Marano et al is a pictorial essay describing the various types of grafts and their appearance on cardiac CT. Since the scanners used are 4-slice and 16-slice, the quality is not as good as those now seen on 64-slice scanners.

Link: A Pictorial Review of Coronary Artery Bypass Grafts at Multidetector Row CT -- Marano et al. 127 (4): 1371 -- Chest.

Decreased intermediate term patency of automated proximal anastomoses evaluated by sequential ultrafast CT

You know that a modality is coming of age, when it is used to differentiate different clinical issues. In this study by Dietrich M et al in the European Journal of Cardiothoracic Surgery, ultra-fast CT was used to look for early restenosis in two different groups of patients going in for saphenous vein graft bypass surgery, one group having regular handsewn anastomosis and the other group having a new automatic clamper with a nitinol implant. More and more now we can use MRI and CT being used as gold standards or methods for assessing and answering clinical issues...this is a "coming of age phenomenon"

16-slice CT for assessment of post-bypass graft analysis

This is one more article on the accuracy of 16-slice CT in the evaluation of venous and arterial conduit patency, by Martuscelli et al in a recent issue of Circulation. Using a 500ms GE scanner, the authors could achieve a sensitivity of 96% in diagnosing significant stenoses.

This is in line with the previous articles that we have discussed in this blog as well as our experience.

4-slice versus 16-slice CT for assessing bypass grafts

This is an article from the January issue of European Radiology by Khan MF et al, where they compared the use of 4-slice and 16-slice CT in the evaluation of bypass grafts. They found that thin MIPs and VRT images are the most useful in assessing grafts, that 16-slice CT depicts grafts better than 4-slice, but that there was no difference in assessing the distal anastomosis.

The latter is a little difficult to understand, though it is likely that the issue is of spatial resolution, not speed and temporal resolution. The 64-slice CT has a far superior spatial resolution of 0.37mm and it is likely that there would be better visualization of the distal anastomosis with this scanner. Our experience so far has been very positive.

Cardiac CT in post-bypass graft assessment compared to coronary angiography

This is an article by Song MH et al from Japan in the Annals of Thoracic Surgery, describing the use of 8-slice CT in the assessment of bypass grafts in 50 patients, two weeks after the bypass surgery, followed by catheter angiography for correlation.

Their results were as follows:
"Multidetector computed tomography succeeded in high-quality imaging of all grafts except for one (less than 1 mm gastroepiploic graft to posterior descending artery). This graft was the only graft that was interpreted differently. Overall patency rate was 97.8%. The diagnostic power of MDCT was as follows: the specificity was 99.4%, the sensitivity was 100%, the positive predictive value was 100%, and the negative predictive power was 80%."

If 8-slice CT can produce such good results, it stands to reason that a 64-slice CT would perform even better. As more and more such articles appear in literature, including the one published on this blog yesterday, the use of cardiac CT in post-bypass graft assessment will become more and more entrenched.

There are two more post-bypass cases on our companion "image" blog. One is with a high heart rate and the other just shows multiple saphenous vein and arterial grafts.

Modification of surgical planning before re-operative surgery based on multi-slice cardiac CT

This is an article from Tel Aviv by Aviram G et al in the Annals of Thoracic Surgery on the use of 16-slice CT in assessing various parameters required to plan re-operative surgery in patients with previous bypass surgery.

The parameters assessed were "Relation of the grafts to the expected median sternotomy line, graft patency and anatomic course, possible aortic cannulation and cross-clamp sites, distances between the right ventricle to the sternum, and calcification of the ascending aorta".

CT was very accurate in assessing all these parameters and actually changed the operative plans in four out of the 15 patients

One more article on the growing use of multi-slice cardiac CT.

There are two more post-bypass cases on our companion "image" blog. One is with a high heart rate and the other just shows multiple saphenous vein and arterial grafts.