Coronary subclavian steal syndrome: non-invasive imaging and percutaneous repair.

Although coronary subclavian steal syndrome (CSSS) is relatively uncommon, it is a well documented cause of graft failure in patients having undergone coronary artery bypass grafting (CABG) using the left internal mammary artery (LIMA). Here we report a case of CSSS induced by restenosis of a left subclavian artery (SCA) origin stent, identified by increased velocities within the stent and an abnormal ipsilateral vertebral artery (VA) waveform on Duplex ultrasound imaging. This was successfully treated percutaneously by re-stenting, resulting in restoration of normal SCA waveforms and velocities, and normalization of the ipsilateral VA waveform.

Imaging and stenting for renal artery stenosis.

Renal artery stenosis is a potentially correctable cause of hypertension and renal failure, using endoluminal or, less commonly, surgical techniques. A number of imaging techniques can be used to diagnose renal artery stenosis, all with similar accuracy.

Treatment of infrarenal aortic stenosis by stent placement: a 6-year experience.

There is a significant re-stenosis rate with percutaneous treatment of stenoses of the infrarenal abdominal aorta with balloon angioplasty. Since 1990 the authors have primarily treated local infrarenal aortic stenoses with metallic endoluminal stents. The authors' experience with 12 consecutive patients (nine women and three men, aged from 30 to 72 years (mean age = 57 years)) is presented. Follow-up is available in 11 cases over 7-78 months (mean 32 months). The procedure was technically successful in all patients. Of the 11 patients with follow-up available, claudication was cured (n = 7) or significantly improved (n = 4). Those with persisting claudication had concurrent distal arterial disease. Periprocedural complications occurred in five cases, with two significant complications. One case required iliac angioplasty for embolized aortic atherosclerotic plaque, and one case required surgical thrombectomy and vein patch for iliac thrombosis complicating iliac dissection, without long-term sequelae in either case. One patient has had recurrent symptomatic aortic stenosis occurring 6 years after initial stenting, which responded to further stent insertion. Primary patency of 91% and secondary assisted patency of 100% has been achieved. Primary treatment of infrarenal aortic stenosis with endoluminal stenting results in high patency rates, with low morbidity and relatively low complication rates.

Magnetic resonance cholangiopancreatography.

Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive imaging method for examining the biliary and pancreatic ducts. The technique uses heavily T2-weighted imaging, which produces high signal from bile and other static fluids by virtue of their long T2 time, while suppressing background signal. Fast scanning techniques, particularly half-Fourier fast spin-echo techniques, are continuing to improve image resolution and allow scans within short breath-holds, reducing the effects of respiratory movement. The MRCP method has reached a level of resolution and reliability where it may well largely replace diagnostic endoscopic retrograde cholangiopancreatography (ERCP) in the near future. A review of MRCP techniques and imaging findings is presented with emphasis on half-Fourier imaging, with reference to potential clinical indications and limitations. Use of MRCP shows a high sensitivity and specificity for detection of biliary dilatation, calculi, strictures and anatomical variants. Experience with MR imaging of the pancreatic duct is less extensively described in the literature, but pancreatic duct dilatation, calculi and anatomy can now be reliably detected. However, as experience with MRCP increases, some sources of errors and limitations are becoming apparent, with image artefacts, and gas, blood or sludge within ducts potentially mimicking stones or strictures.

Diffusion-weighted magnetic resonance imaging of intracranial epidermoid tumours.

Intracranial epidermoids can closely mimic cerebrospinal fluid (CSF) on MRI and CT. Therefore epidermoids can be difficult to detect, or distinguish from CSF. Three cases of intracranial epidermoid are presented, one of which closely mimicked an arachnoid cyst on CT and routine MRI sequences. Diffusion-weighted magnetic resonance imaging (DWI) was performed. All three epidermoids demonstrated marked restriction of diffusion relative to CSF, clearly defining the extent of each lesion, and allowing differentiation from an arachnoid cyst or an enlarged CSF space.

Stenting in malignant and benign vena caval obstruction.

Expandable metallic stents have been used with considerable success for the palliation of malignant vena caval obstruction. The role of stenting in vena caval obstruction of benign aetiology is less well defined. A review of 11 patients stented for vena caval obstruction and a review of recent series in the literature is presented. Of the 11 patients, seven patients had involvement of the superior vena cava (SVC), and four patients had inferior vena caval (IVC) obstruction. Seven cases had malignant vena caval obstruction, with a benign aetiology (SVC n = 3; IVC n = 1) in the other four cases. All seven patients treated with SVC stents experienced complete resolution or significant improvement in symptoms with no recurrence over the duration of available follow-up, over an average of 4.3 months (range: 1 week-12 months). Only one of four IVC lesions stented resulted in a good clinical response. All four patients with vena caval obstruction of benign aetiology had a good outcome. One patient experienced a small pulmonary embolus following SVC stent insertion without further sequelae. No other serious complications were encountered. Stenting can provide prompt relief of vena caval obstruction with low morbidity, and high patency rates in both benign and malignant vena caval lesions.

MRI of the liver.

MRI of the liver is a powerful imaging modality for detection and characterization of liver pathology. MRI technology continues to evolve with developments in scanner hardware performance and refinements in imaging sequences, particularly in respect to fast imaging techniques, improving the quality of images that can be routinely achieved. Fast imaging techniques allow dynamic contrast-enhanced scanning to assist in lesion detection and characterization. An array of tissue-specific contrast agents are also becoming available; the clinical utility of some of these agents is yet to be fully established. An overview of scanning technique, contrast media, and the role of MRI in liver lesion detection and characterization is presented, with a review of the typical imaging characteristics of common focal and diffuse hepatic diseases. Where possible, emphasis has been placed on features that allow distinction between the various pathologic entities described.