[Three-dimensional computed tomography angiography of coronary artery bypass graft with electron beam tomography].

OBJECTIVES: Assessment of coronary artery bypass graft patency by three-dimensional reconstructed computed tomography angiography (3D-CTA) derived from electrocardiography-gated contrast-enhanced electron beam tomography (EBT) was evaluated. METHODS: Thirty-nine patients with 99 grafts (45 arterial grafts and 54 venous grafts) underwent 3D-CTA and selective coronary angiography within a 3-week interval. 3D-CTA images of the coronary bypass grafts were compared with the coronary angiography images used as the control. RESULTS: 3D-CTA defined 42 of 44 arterial grafts as patent (sensitivity: 95%), all 47 venous grafts as patent (sensitivity: 100%) and all 7 venous grafts as occlusive (specificity: 100%). The overall sensitivity and specificity were 98% and 88%, respectively. CONCLUSIONS: 3D-CTA is an useful noninvasive technique with adequate sensitivity and specificity to assess coronary artery bypass graft patency.

[Gd-enhanced subtraction MR venography].

We succeeded in distinctly imaging the calf veins using Gd-enhanced subtraction MR venography (Gd SMRV). Gd SMRV was performed in 15 normal legs, 33 varicose legs and 22 legs with suspected deep venous thrombosis. Conventional venography was performed in 46 legs in all. The deep veins of the calf, greater saphenous vein, and intramuscular veins had high rates of demonstration in normal legs and varicose legs (84, 100%, 87, 97%, 67, 73%). The varices were also well demonstrated (100%). When Gd SMRV was compared with conventional venography in terms of diagnosis of calf venous thrombosis, the sensitivity of this method was 100%, specificity was 92% and accuracy was 93%. We found high intensity thrombi on precontrast images in most cases, a finding that was important for the diagnosis of local thrombi. This method was non-invasive and was able to clearly visualize veins in the calf. We concluded that Gd SMRV was useful for calf venous disease, especially calf venous thrombosis.

[Usefulness of myocardial T2-weighted MR imaging using the turbo spin echo technique].

Myocardial T2-weighted imaging using the turbo spin echo technique was superior to the conventional spin echo technique because of the shorter scan time and reduced artifacts. Furthermore, single cardiac phase images of all planes could be taken within a short scan time. T2-weighted imaging using the turbo spin echo technique was an effective method to evaluate myocardial abnormalities.

A retrospective survey of delayed adverse reactions to ionic and nonionic contrast media.

A comparative survey of delayed adverse reactions (DARs) to ionic and nonionic contrast media (CM) was carried out. In Japan high osmolar CM have mostly been replaced by new low osmolar CM. Therefore, a retrospective survey was performed limited to inpatients who had received an enhanced CT examination in our hospital. The material consists of 715 consecutive cases given ionic CM (iothalamate and diatrizoate) and 902 given nonionic CM (iopamidol and iohexol). DARs were picked up based on descriptions in the medical record up to 5 days after the examination. Most DARs had occurred within two days after the examination. Overall DARs were noted in 36 cases (5.0%) of the ionic group, and 44 cases (4.9%) of the nonionic group. Skin rash as well as other symptoms revealed no significant difference in incidence between the ionic and the nonionic group. There were no significant associations with immediate reactions, allergy, previous adverse reactions to CM. One patient given an ionic CM developed hypotension (60 mmHg) after return to the ward. It should be emphasized that a delayed shock had been recorded.

[CT guided selective pneumomediastinography in thoracic imaging].

We established new approaches for CT guided selective pneumomediastinography; paravertebral, pretracheal and anterior mediastinal approaches. CT would seem to be useful method for assessing the invasion to the neighboring structures in the thoracic neoplasms. But scanty fat in mediastinum often interferes with correct evaluation of mediastinal structures in conventional CT. Pneumomediastinal CT with our methods overcomes the weak point and provides additional information to enable exact diagnosis. The feasibility and security of these methods were confirmed through applying to many cases. Based upon these results, selective pneumomediastinal CT would be considered to be advantageous and advisable on the CT diagnosis in thoracic imaging.