A study was performed to determine which magnetic resonance (MR) imaging findings are useful in discrimination between metastatic compression fractures and acute osteoporotic compression fractures of the spine. The MR imaging findings in 27 patients with metastatic compression fractures and 55 patients with acute osteoporotic compression fractures were compared by using the chi(2) test. MR imaging findings suggestive of metastatic compression fractures were as follows: a convex posterior border of the vertebral body, abnormal signal intensity of the pedicle or posterior element, an epidural mass, an encasing epidural mass, a focal paraspinal mass, and other spinal metastases. MR imaging findings suggestive of acute osteoporotic compression fractures were as follows: a low-signal-intensity band on T1- and T2-weighted images, spared normal bone marrow signal intensity of the vertebral body, retropulsion of a posterior bone fragment, and multiple compression fractures. The signal intensity on fast spin-echo T2-weighted images obtained without fat suppression played little role in distinguishing between metastatic compression fractures and acute osteoporotic compression fractures.

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MR imaging was accurate for predicting reparable meniscal tears and was sensitive for the determination of nonreparable tears.

To evaluate the helical CT findings of ruptured hepatocellular carcinoma (HCC), 12 patients with ruptured HCC were reviewed with regard to the tumour's location, size and contour protrusion, the appearance of the mass, the enhancement pattern, multiplicity and secondary changes. All ruptured tumours were located at the periphery of the liver and had a protruding contour. The maximum diameter of tumours ranged from 2 cm to 16 cm. Discontinuity of the hepatic surface was seen in 11 cases. In eight cases, CT images during the arterial phase showed a non-enhancing low attenuating lesion with focal discontinuity and peripheral rim enhancement. Seven cases showed separation of tumour content from the peripheral enhancing rim and intraperitoneal rupture of tumour content into the perihepatic space. Because of the similar appearance to an enucleated orbital globe with remaining sclera, this was termed the "enucleation sign". As well as ruptured masses, 10 cases with non-ruptured masses also showed a non-enhancing low attenuating pattern. Seven cases showed a haematoma with high attenuation around the ruptured mass. The peripheral location, protruding contour, discontinuity of the hepatic surface and surrounding haematoma are helpful signs in the diagnosis of ruptured HCC. The "enucleation sign" may be a characteristic finding in ruptured HCC.