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

Intracranial hematoma secondary to superior sagittal sinus thrombosis is a well described, but rare event. We present a case of interval resolution of a intracerebral hematoma in a patient with thrombosis of the sagittal sinus.

Residual iophendylate in the spinal subarachnoid space may closely resemble certain spinal canal tumors on MR imaging of the spine. A knowledge of the appearance on MR imaging scans of iophendylate is essential to differentiate it from spinal tumors.

Six patients receiving anticoagulant medication who had laboratory evidence of impaired hemostasis as manifested by laboratory parameters exceeding the therapeutic range developed intracranial hemorrhages. None of these patients had a history of preceding trauma. None of the 6 anticoagulated had CNS symptoms prior to inititation of anticoagulant medication. Within the intracranial hemorrhage there was a fluid-blood interface in these 6 patients; this finding was seen only in hemorrhages in anticoagulated patients. In 3 cases the fluid-blood interface changed to a homogeneous hyperdense lesion when adequate hemostasis was achieved. In one case there were multiple hemorrhages and in the other there was a solitary intracerebral hemorrhage.

Low back pain and/or pain radiating to one or both lower limbs can result from causes other than intervertebral disc disease. Recently three patients presented with low back pain radiating down the legs. When CT examination of the lumbar spine proved unrewarding, magnetic resonance imaging (MRI) was performed. Avascular necrosis (AVN) of the femoral head was diagnosed and subsequently treated before femoral head collapse occurred. In patients with unexplained low back pain, AVN of the hip should be considered and ruled out by MRI, even if conventional plain films, polytomes, and radionuclide scans are negative. The early diagnosis of AVN of the femoral head may be critical in determining whether a surgical revascularization procedure might be successful in treatment, or replacement with an endoprosthesis will be necessary, if femoral head collapse has already occurred.

A case of acute rupture of a right middle cerebral bifurcation aneurysm with extravasation of blood into a distant arachnoid cyst is reported.

The CT findings in a patient with tuberous sclerosis are described with special emphasis upon the differential diagnosis. The presence of multiple bilateral subependymal nodular nonenhancing hyperdense calcified lesions is relatively characteristic of tuberous sclerosis when combined with the appropriate clinical findings. In some cases, cerebral cortical heterotopias are visualized as hypodense nonenhancing sub-ependymal lesions. The finding of a sub-ependymal giant cell astrocytoma is sometimes seen in patients with tuberous sclerosis, and the finding of a subependymal hyperdense enhancing lesion is consistent with this diagnosis.

The CT values of 15 cases of orbital hydatid cyst operated upon by the author were reviewed. It was found that hydatid cyst of the orbit has high CT value, contrary to the low CT value of nonorbital hydatid. This discrepancy was confirmed by an experiment using human skull and two balls simulating hydatid cyst. One ball was put in the orbit and the other in the cranial cavity. When the skull was CT scanned it was found that the orbital ball CT value was about five times higher than the cranial ball, in spite of the fact that both balls had the same content. It was concluded that the orbital bony pyramid is the cause of this high CT value in orbital hydatid. Hence it is recommended that an orbital lesion with a high CT value can be a hydatid cyst.

Epidermoid and dermoid tumors are uncommon lesions and within the spinal cord are rare. Magnetic resonance imaging has proved sensitive to their detection in the intracranial cavity but the pattern of signal intensities on T1 and T2 weighted images has not been uniform. Utilizing a 0.6 T superconductive magnet an intrarnedullary cervical dermoid tumor was examined. The correlation between CT demonstrated regions of fat density and the MRI appearance of comparable regions of high intensity signal on T1 weighted images has only rarely been demonstrated in such tumors that have no histologic evidence of adipose tissue. MRI provided all of the information needed pre-operatively.

The use of a nasogastric tube to empty the stomach contents prevents compression of the splenic parenchyma and allows clear visualization of the anterior medial border of the spleen and perisplenic area. Unsuspected superficial lacerations or a contained hematoma by the splenic capsule may become apparent only following this procedure. A representative case is reported. Routine application of this simple procedure aids avoiding occasional pitfalls and helps in early diagnosis of splenic injury at the time of a CT study.