Cardiac CT & MRI Literature

Assessment of the radial artery and hand circulation by computed tomography angiography: a pilot study.

This is a pilot study on the use of CT angiography in the assessment of patients who are to go for a cardiac bypass surgery using the radial artery. Color Doppler currently is the modality of choice, but it is likely that CTA could become a modality of choice, due to its inherent superiority in demonstrating the anatomy and calcification as well as other pathologies.

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"

Endomyocardial fibrosis - case

An interesting case of biopsy proved endomyocardial fibrosis, by Cury R C et al,  has been published in a recent issue of Circulation.

Images published include those of a cardiac cath and MRI, both cine and delayed hyperenhanced images, which show diffuse subendocardial enhancement.

Cardiac sarcoidosis

This is a pictorial essay on the MRI features seen in cardiac sarcoidosis, published by Vignaux O, in the January issue of the AJR. Patients with cardiac sarcoid show involvement of the myocardium with varying degrees of inflammation, granuloma formation and scarring. Acute edema and inflammation can be seen on T2W images, whereas the rest of the features require a combination of delayed hyperenhanced images and cine images.

Two representative cases are available in the accompanying images blog for viewing, one published today and one in January.

Cardiac CT in assessing chronic total occlusions for stent placement

Continuing from yesterday with understanding possible indications of cardiac CT, is an article from Mollet NR et al from Erasmus University, Rotterdam, published in the January issue of the American Journal of Cardiology.

This article is an initial study on 15 patients, studying the factors that affect the outcome of stent placement in chronic total occlusions. "Multivariate analysis identified a blunt stump (by conventional angiography), occlusion length >15 mm, and severe calcification (by multislice computed tomographic coronary angiography) as independent predictors of procedural failure."

This should be one more potential indication for cardiac CT. Patients with chronic total occlusions identified on coronary angiography, prior to stent placement could get a CT done to assess the length of the stenosis and the extent of calcification.

Noninvasive evaluation of type 2 diabetes patients with MSCT

Schuijf et al from Leiden have another article similar to the one published yesterday on this blog, in Diabetes Care, describing the use of 16-slice CT in patients with type 2 diabetes. The results obtained are a shade inferior to those in the patients with hypertension.

They had a sensitivity and specificity of 95% but with 86% interpretable segments. With the inclusion of non-interpretable segments, the sensitivity and specificity drop to the low 80s.

Noninvasive evaluation of hypertensive patients with MSCT

This is an interesting article by Schuijf et al from Leiden, in Hypertension, describing a study performed on a 16-slice Toshiba, without beta-blockers, assessing the usefulness of cardiac CT in triaging patients with hypertension.

31 patients were studied and 243 coronary artery segments could be evaluated. The sensitivity and specificity was 93% and 96% respectively, with an accuracy of 90% (24/31) on a per patient basis. The evaluation of ejection fraction and wall motion abnormality as compared to 2D-echocardiography was also accurate.

The authors suggest that in hypertensives, who have some form of atherosclerotic disease, using cardiac CT as an initial modality to evaluate function and the coronary arteries may be feasible proposition.

Accuracy of 16-slice CT with a 375ms rotation tube

Two new articles on the accuracy of 16-slice CT with a 375ms rotation tube have been published in JACC in the early part of this year. The first is by Mollet Nico et al from Erasmus University, Rotterdam and the other by Kuettner Axel et al from Tubingen. At both these centres, the scanners on which these studies were performed, no longer exist. They have now been superseded by 64-slice scanners with 330ms rotation tubes and the results from both these centres on the new scanners are better than the ones published using the older scanners. These new results were presented at the recent ECR held last month.

Mollet et al's study is of 51 patients where catheter angiography was the gold standard and the negative predictive value for detection of significant lesions on a segment-based analysis was 99%. The positive predictive value was 87%.

In the second study by Kuettner et al, 72 patients were studied and their negative predictive value for the whole study group was also 97%.

This is again in line with our own experience. A study published at our centre (Bajaj et al, unpublished) on 50 consecutive patients, showed a negative predictive value of 97% as well.

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.

Interventricular septum and pulmonary arterial pressures in pulmonary hypertension

Assessing pulmonary arterial pressures non-invasively is not easy. On MRI it is a bit complicated and there has been one such method described by Laffon et al from France.

A slightly simpler method is the one described by Roeleveld RJ et al, in Radiology, where they compared the curvature of the interventricular septum with RV and pulmonary arterial pressures. They found that when there is leftward bowing of the septum in end-systole, it means at least a pulmonary arterial pressure of 67mm Hg.

This is helpful to a certain extent, since assessing septal curvature qualitatively is very easy on cine MRI images.

There is an accompany case in the images blog.