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

Three patients with right subclavian artery aneurysms are presented. CT can be useful in making the diagnosis. It depicts the relationship of the aneurysm to the surrounding anatomical structures and displays intraluminal thrombotic material.

The DSA system has been upgraded for capabilities of slow scan video technique and progressive T.V. read-out of 1024 × 1024 matrix with 10 bits of depth. A square wave test pattern made of lead bar demonstrated moderate improvement in spatial resolution, but imaging of a Burger-Rose phantom revealed no significant increase in contrast resolution. Clinical study of various angiograms with intraarterial injections showed that there was slight improvement in the visibility of the vessels, especially small arterial branches, while there was no increase in visibility of the veins. There were no cases in which diagnoses were altered by application of high resolution DSA. With future improvements of the image intensifiers, DSA with 1024 × 1024 matrix may reveal its potential advantage, especially when coupled to larger image intensifiers such as 12 or l4 in.

This paper describes the performance characteristics of a laser scanner and laser printer system for radiological imaging. The laser scanner can digitize a 14″ × 17″ X-ray film to 2000 × 2400 x 10 bit in about 100 s. The laser printer can format 16 images on a 8″ × 10″ or 14″ × 17″ film with up to 2300 × 3050 × 8 bit resolution in about 50 s. Our experiments show that the laser scanner and the laser printer have a spatial resolution of 3 cycles/mm with excellent spatial linearity and flat field response. This system is a major component of a picture archiving and communication system in a digital-based radiology department. As a stand-alone system, it has certain clinical applications such as a contrast enhancement of radiographs and potential dose reduction to the patient.

Biplane digital subtraction angiography was performed by placing a rapid switch between the anteroposterior and lateral T.V. cameras and the A-D converter. Alternate exposures from two X-ray tubes were employed. Excellent anteroposterior and lateral DSA was obtained especially for the brain and neck. Although there was more time required for positioning, biplane imaging saved the second or the third injection in many occasions. The technique has been especially valuable for intravenous DSA of the brain and the neck.

A 65-year-old female with an intracerebral cyst was examined in our clinic. It was suspected to be a cystic glioma by the preoperative neuroradiological studies, even with the use of sophisticated CT techniques. By operative and histopathological examination, it was confirmed as an arachnoid cyst mainly embedded in the parenchyma.

The clinical and CT findings in 20 patients with isodense subdural hematomas (SDH) are analyzed. The lesions were unilateral in 15 and bilateral in 5 cases. Three patients presented with episodes of transient neurological deficit. Eleven patients presented with the sudden onset of fixed focal neurological deficit. Nineteen of 20 patients had abnormal neurological findings on the initial neurological examination. In those patients with unilateral SDH, CT showed ventricular mass effect, midline shift, and sulcal space effacement in all cases. There was medial membrane enhancement in 12 cases. In the 5 cases of bilaterial isodense SDH, the lesions were of different sizes in 3 and of equal size in two cases. The bilateral SDH showed ventricular mass effect and sulcal space effacement; however midline shift was seen in only three and none showed medial membrane enhancement.

Paragangliomas are usually benign tumors which may be locally invasive. Only 10% of these tumors are malignant. When metastases occur the most common sites are lung, liver and bone. When bony metastases occur the spine is a common site. In the present case cervical spine metastases with resultant bony encroachment: and epidural extension of tumor with cord compression was diagnosed with myelography and CT.