Budd-Chiari syndrome: CT observations

The authors describe four patients with Budd-Chiari syndrome in whom contrast material-enhanced computed tomographic (CT) scans demonstrated low-density venous thrombosis in three sites not, to our knowledge, previously described with this modality. Thrombosis was seen in the portal circulation, the hepatic veins, and the intrahepatic inferior vena cava. It is known that concomitant portal vein thrombosis may be seen in 20% of patients with Budd-Chiari syndrome. Three of the four patients in the current study had this finding, one with extensive thrombosis of portal, mesenteric, and splenic veins and the other two with portal vein branch involvement. In one patient hepatic vein thrombosis was demonstrated with CT, and in three inferior vena cava clot was demonstrated. All four patients had the distinctive hepatic parenchymal contrast enhancement pattern seen in this condition, which the authors think may be at least partially caused by associated portal thrombosis. The presence of portal venous thrombosis should prompt the observer to consider the diagnosis of Budd-Chiari syndrome. Detection of hepatic vein clot confirms the diagnosis and may be seen in this condition in association with inferior vena cava thrombus.     

Spatial presaturation: a method for suppressing flow artifacts and improving depiction of vascular anatomy in MR imaging

In clinical magnetic resonance (MR) imaging, the diagnostic quality of examinations is often degraded by streaklike flow artifacts that obscure anatomic details and reduce contrast. In addition, vascular structures are often not depicted clearly because the desired flow voids are obliterated by spurious intraluminal signals. On the basis of analysis of the physical mechanism of flow artifact formation, the authors developed a new technique for suppressing these artifacts. This applies interleaved, spectrally shaped radio frequency pulses to selectively saturate spins located in regions outside the image volume. In phantom, volunteer, and clinical imaging studies, the technique has proved to be effective by yielding a striking reduction in flow artifacts and markedly improving the reliability with which arterial and venous structures are imaged. The method has few drawbacks: It is applicable to most MR pulse sequences and, in principle, can be implemented on most imagers. It is particularly helpful for high-resolution surface coil studies of the neck, mediastinal imaging, gated cardiac imaging, and for detecting thrombus and other intravascular lesions such as dissections.