Intercostal lung herniation--depiction on spiral CT.

Computed tomography (CT) is the imaging modality of choice for the demonstration of intercostal lung herniation. The use of forced expiration and Valsalva's manouevre during CT scanning has been recommended in selected cases. We report a case of intercostal lung herniation, demonstrated only on coughing on spiral CT.

Magnetic resonance angiography.

The field of MRA has progressed to a stage at which several clinical applications are of obvious value, including the diagnosis of cerebral aneurysms, venous disorders and disease of the carotid bifurcation. Additionally spin echo images are useful in studying the parenchyma and this together with MRA works to be an excellent diagnostic package in the presurgical workup of patients with cerebral vascular abnormalities. With further technical improvements, it seems likely that important applications of MRA will also be found in the diagnosis of peripheral artery disease, stenosis of the renal artery and ischemic heart disease. With the advent of fast imaging techniques like echoplanar imaging, the ability image the coronary and renal arteries accurately seems possible in the near future. At present, however the lack of optimal spatial resolution and the presence of flow artifacts precludes the use of this technique for imaging the vasculature with an accuracy comparable with conventional angiography. The advent for contrast 3-D CT angiography has resulted in a technique of studying the intracranial vessels immediately after assessing for the presence of subarachnoid hemorrhage. It is superior to MRA in demonstrating the actively filling and thrombused portions of giant, partially thrombused aneurysms and in planning the surgical approach in relation to bony landmarks. Though there are daunting obstacles, with continuous ongoing clinical research and the added inputs from a dramatically changing computer technology, MRA is all set to be an imaging study of great promise that may eventually replace diagnostic catheter angiography in most clinical situations.

Comparison of MR angiography with contrast angiography for the diagnosis of carotid artery stenosis.

To assess the accuracy of MR angiography for screening vascular stenosis of the extracranial carotid arteries, 20 consecutive patients with suspected extracranial carotid atherosclerotic disease were evaluated with time-of-flight MR angiography and intra-arterial contrast angiography. Both studies were independently reviewed by three observers in a blinded manner. The internal carotid arteries were graded as either normal or mildly stenotic (0%-29%), moderately stenotic (30%-69%), severely stenotic (70%-99%) or occluded. Results of the study indicate that time-of-flight MR angiography has a high rate of agreement with contrast angiography and is an accurate screening technique of the common carotid bifurcation in patients with suspected carotid stenosis.