Masayuki Miyawaki

Increased MR signal intensity secondary to chronic cervical cord compression

SummaryMagnetic resonance images of 128 patients with compressive lesions of the cervical spinal canal were reviewed to determine whether a high signal intensity lesion within the spinal cord was present on T2 and proton density weighted spin echo images. Such high signal intensity was observed in 24 cases or 18.8%. The incidence was higher in herniated disk (32.4%), atlanto-axial dislocation (28.6%), and ossification of the posterior longitudinal ligament (22.7%), whereas the abnormality was found sporadically in cervical spondylosis and vertebral body tumors. The high intensity lesion on T2 weighted images was generally observed in patients with constriction or narrowing of the spinal cord. The lesion was not demonstrated on T1 weighted spin echo images. Spinal cord constriction or localized narrowing seemed to be the most important portant predisposing factor in producing such a high signal intensity. The pathophysiologic basis of such an abnormality was presumed to be myelomalacia or cord gliosis secondary to a long-standing compressive effect of the spinal cord.

Cerebral vasculitis secondary to Wegener's granulomatosis: computed tomography and angiographic findings

The central nervous system is rarely involved by Wegeners granulomatosis. A case of Wegeners granulomatosis with involvement of the cerebral arteries was reported. Computed tomography showed extensive brain edema with angiographic demonstration of cerebral vasculitis.

The value of Digital subtraction angiography in peripheral vascular diseases

The iliac and subclavian arteries and their distal branches were studied by digital subtraction angiography (DSA) in 79 patients and the results compared with conventional angiograms for 35 patients. Techniques, results, advantages and disadvantages are described. DSA (both intravenous and intra-arterial) looks very promising in the diagnosis of peripheral vascular disease.

Stereoscopic DSA of the central nervous system

SummaryStereoscopic DSA is performed with alternate exposures from a twin focal X-ray tube (6,5 cm focal separation). Excellent intravenous and intraarterial DSA images of the cerebral vessels are obtained with separation of overlapping parts of the normal and abnormal vasculature. The clinical value of DSA has been enhanced by use of stereoscopic DSA.

Development of a new universal neuroangiographic unit

SummaryA new neuroangiographic unit has been developed with use of a “C” type gantry, which is capable of rotation and angulation for various angiographic projections. Two sets of a twin focal X-ray tube and an imaging system are mounted on the gantry. Each imaging system consists of a 9 inch image intensifier and a 14 x 14 rapid film changer, which can be exchanged in position rapidly. Stereoscopic magnification and stereoscopic contact angiography, fluoroscopy and DSA are performed in monoplane and biplane and switched over to each other expeditiously and easily. The detailed angiographic information is obtained with lower complication rate and lower exposure to patients. Interventional neuroradiologic procedures are performed efficiently on this unit.

Percutaneous transluminal angioplasty for renal branch stenosis--a report on a six-year-old boy.

Percutaneous transluminal angioplasty (PTA) was originally developed by Dotter and Judkins (1964) for treatment of atherosclerotic peripheral diseases. However, application to renal artery stenosis was not described until 1978 (Gruntzig et al, 1978). Although PTA has become a well established procedure in correcting hypertension due to main renal artery stenosis in adults, we know of few studies in paediatric patients with branch stenosis of the renal arteries. The purpose of this paper is to report a paediatric case of successful PTA on a segmental renal artery.

Intraarterial digital subtraction angiography vs conventional angiography of abdominal diseases

Seventy-five patients with various abdominal diseases were studied by intraarterial digital subtraction angiography (IA DSA) during conventional abdominal angiographic examinations. The image quality, tumor stain, and arterial encasements were evaluated and diameters of vessels visualized by IA DSA were measured. The vessels greater than 2.0 mm or more in diameter were equally well demonstrated on IA DSA. IA DSA demonstrated tumor stains and portal system to good advantage. Real time imaging was also advantageous during an embolization procedure.

Diagnostic accuracy of intravenous digital subtraction angiography for peripheral vascular diseases

Intravenous digital subtraction angiography (IV DSA) was performed on 406 regions of 241 patients with peripheral vascular diseases. The results were compared with conventional angiograms for 167 arteries. There was excellent correlation between conventional angiograms and IV DSA. The diagnostic accuracy was 95 with 97% sensitivity and 94% specificity when more than 60% stenoses were taken into consideration. DSA is a less-invasive procedure which can be performed on out-patients for screening and follow-up evaluation of peripheral vascular diseases.

Use of short-tapered catheters in combination with a balloon catheter for markedly stenotic renal and brachiocephalic arteries

Percutaneous transluminal angioplasty (PTA) has become a routine therapeutic technique for steno-occlusive arterial diseases. In the renal and brachiocephalic arteries, stenosis is frequently severe and a dilatation balloon catheter cannot be advanced through the stenosis, although a small catheter or a guide wire can be passed. Under such circumstances a small balloon catheter, as used for coronary artery angioplasty, has been applied with some success, (Korogi et al, 1985). However, there have been some cases in which this was not possible. In marked stenosis of the iliac and femoro-popliteal arteries, advancement of a guide wire is usually initiated with subsequent introduction of a long tapered Teflon catheter, which prepares the pass for a dilatation balloon catheter (Van Andel, 1976; Rosen et al, 1981). To avoid this, Barth (1983) devised a tapered balloon catheter but because of technical difficulties encountered with this method (see discussion) we have designed short-tapered catheters of varying ...