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B K Wallner

Publications and source records attributed to B K Wallner.

3 recordsLinked to original sources
PubMed1993

Central venous occlusion: MR angiography.

The authors evaluated time-of-flight magnetic resonance (MR) angiography in 30 patients with suspected thoracic venous occlusion. The results of the MR studies were compared with results at contrast venography in 22 patients and at central venous cannulation in seven of the remaining eight patients. Twenty-eight patients had abnormalities on MR venograms; 21 of these abnormalities involved multiple veins. Eight patients had superior vena cava (SVC) occlusion with retrograde azygos blood flow, and two patients had nonocclusive SVC thrombus. Fifteen patients had thrombosis involving the brachiocephalic veins; 14, involving the subclavian veins; and eight, involving the internal jugular veins. Correlation was excellent between findings of venous obstruction and occlusion at contrast venography and MR angiography. MR imaging provided more comprehensive information than catheter venography on central venous anatomy and blood flow. For evaluation of central veins, MR angiography is an accurate and graphic technique that may succeed in cases in which other methods may give inadequate findings or may be impossible to perform.

Adult↗
PubMed1991

Dilated biliary tract: evaluation with MR cholangiography with a T2-weighted contrast-enhanced fast sequence.

A heavily T2-weighted gradient-echo sequence was used for magnetic resonance (MR) imaging of the biliary system in five healthy volunteers and 13 patients with obstructive jaundice. Images were obtained in the sagittal and coronal planes during sequential breath-hold intervals and were post-processed by using a maximum-intensity projection algorithm. The extrahepatic and intrahepatic bile ducts were well visualized in 11 patients. The level of obstruction and the grade of dilatation were depicted with MR cholangiography. However, the cause of obstruction could be determined with MR cholangiography in only eight cases. The part of the biliary system below the obstruction could not be visualized with MR cholangiography. In the volunteers, MR cholangiography could demonstrate the anatomy of the biliary tract in only two subjects. Possible causes for this phenomenon are the limited spatial resolution of MR imaging, partial volume effects, or flow within the bile ducts. MR cholangiography may be a useful adjunctive tool for noninvasive evaluation of patients with obstructive jaundice. However, further technical advances are necessary to improve image quality.

Bile Ducts↗