Computerized radiology : official journal of the Computerized Tomography Society最新文献

Fenestration or duplication of a cerebral vessel is a rare congenital variation which most commonly involves the vertebral artery and is usually of no clinical significance. Fenestrations may have associated aneurysms remote to the anomaly or involving the proximal bifurcation of the fenestration. They may also be associated with other vascular malformations e.g. arteriovenous malformations and venous angiomas. Four fenestrated cerebral vessels and their angiographic appearances are reported in this study.

The interesting case of the left oculomotor nerve paralysis with right hemiparesis following minor head trauma was reported in this paper. Computerized tomography showed clearly the intracranial lesions suggesting the oculomotor nerve avulsion.

Perinatal hypoxic-ischemic injury is an important cause of neurological deficit in infants. The hypoxic-ischemic process causes symmetrical periventricular and subcortical hypodense lesions which represent ischemic infarcts. It is important to be able to differentiate these hypodense lesions which represent ischemic infarcts from white matter which is not well myelinated. The temporal pattern of the change in the CT findings may be helpful in differentiating hypodensities due to ischemic infarct from immature myelination.

In the setting of a questionable pulmonary nodule demonstrated by conventional radiographs, the place of CT in the diagnostic algorithm is not well established. We reviewed our experience in 50 consecutive patients referred to CT for a “possible pulmonary nodule.” From the chest radiographs we noted nodule location, maximum dimension, presence on one or both views, and presence on a previous radiograph (> 1 year old), and nodules were categorized as “likely” or “unlikely” to be real parenchymal lesions based on radiographic appearance. Of a total of 56 questionable nodules, CT demonstrated no abnormality in 21 cases, parenchymal nodules in 16, scarring, atelectasis, or infiltrate in 11, and normal structural variants in 8. True pulmonary nodules were statistically significantly more frequently categorized as “likely” lesions than normal variants or no disease, but this was not of a magnitude to be clinically useful. Based on analysis of various radiographic features of equivocal nodules and their subsequent outcomes, we suggest a radiologic approach to the equivocal pulmonary nodule.

A case of peritoneal mesothelioma is presented in which CT demonstrated abnormal regions of increased vascularity in the omentum corresponding to hypervascular omental lesions shown by angiography. This CT appearance has not been described in prior reports of CT in peritoneal mesothelioma.

A case of chordoma involving the thoracic spine (T12) is reported. The plain film findings included lytic obstruction and partial collapse of a single vertebral body. Noncontrast CT and CT following Metrizamide myelography revealed vertebral body destruction with paravertebral and intraspinal soft tissue masses. Unusual findings in the case included a photon deficient area on nuclear medicine corresponding to the lesion and normal vascularity on spinal angiography. We know of no previous report describing chordoma as a “cold” defect on bone scanning.

A case of biopsy documented subacute encephalopathy of AIDS was evaluated by CT and MRI. CT scanning revealed ventriculomegaly and ill-defined nonspecific periventricular white matter hypodensities. MRI, however, demonstrated extensive unequivocal diffuse white matter disease as the cause of the ventriculomegaly. MRI findings in this patient support the preliminary suggestion that MRI is more useful than computed tomography (CT) in demonstrating AIDS subacute encephalopathy.

Difficulties in the diagnosis of cerebral thrombosis are due to the nonspecificity of symptoms and signs and the infrequent occurrence on computed tomography (CT) of direct signs of cerebral sinus thrombosis, i.e. the empty delta sign and cord sign. We present two patients, a 24/12-year-old girl with nephrotic syndrome, coma, papilledema, and hyperdensity along the sagittal sinus on CT; and a 34-year-old man with headaches, episodic visual loss, papilledema and a normal CT following posterior fossa craniotomy. On MRI, there was increased signal in sagittal and straight sinuses in the first patient, and in the lateral sinus in the second patient. The increased signal from clot, and the absence of signal from flowing blood, make MRI the procedure of choice for the initial diagnosis of cerebral sinus thrombosis.

Chest radiographs and computed tomographic (CT) findings in 42 patients with pathology of the middle or posterior mediastinum, confirmed by thoracotomy, were examined retrospectively. The possibility of using contrast-enhanced CT to distinguish between cysts and solid tumors on the one hand and benign and malignant tumors on the other was assessed. All the expansions were detectable on chest radiographs. It was only by using CT, however, that the extent of the tumors could be established. Simple cysts could be identified because of their water density even without administration of contrast medium. Bronchogenic cysts simulated solid tumors but showed no contrast enhancement. Other benign tumors showed both intense homogeneous and heterogeneous contrast enhancement, as did malignant tumors. Contrast enhancement was therefore not helpful in distinguishing these benign tumors from malignant ones. Thus only infiltration to adjacent organs was found indicative of malignancy; contrast medium administration was found helpful in this respect. The use of contrast medium is thus justified in studying expansions in the middle and/or posterior mediastinum.