Conjoined Lumbosacral Nerve Roots without Disc Herniation: Case Report / 대한정형외과학회잡지

Anomalies of the lumbosacral nerve roots, in which conjoined nerve roots are most common, are occasionally accompanied by herniated nucleus pulposus. Most of these anomalies were incidental findings from operations, and recent advances in diagnostic imaging techniques have increased the number of cases of lumbosacral root anomalies reported. All these anomalies are congenital, unilateral and almost exclusively situated at the L5-S1 segment. Diagnostic techniques, such as myelography, CT and MRI detect conjoined nerve root. Conjoined nerve root may be confused with a dumbbell tumor or extruded free disc fragment on CT scans. Surrounded by high-signal intensity epidural fat, a conjoined nerve root is more clearly depicted on MR images than on CT scans. Although the size of disc herniation was small, the symptom was magnified by a relatively fixed conjoined root. At surgery, it is necessary for a larger surgical exposure by means of hemi-laminectomy because of the fixation of the nerve roots, and difficulty in retraction. Recently, we experienced two cases of conjoined nerve root and presented them with a review of the literature.

Noninvasive Evaluation of Coronary Artery Bypass Graft Patency by Electron Beam Tomography / 대한흉부외과학회지

Recently non-invasive diagnostic imaging replaced the invasive catheter angiography in the diagnosis of vascular disease. Catheter methods are now almost confined to the purpose of intervention. Coronary artery or coronary artery bypass graft still needs catheter technique because of small diameter and the cardiac motion. The last challenge for radiologists in this domain is to obtain a non-invasive imaging. Electron beam tomography(EBT) for high temporal resolution is able to obtain a coronary arteriogram or coronary artery bypass graft (CABG), of which CABG imaging is quite useful for the evaluation of patency. In our experience as well as others, the accuracy of EBT angiogram in evaluating CABG patency revealed that the accuracy of patency of saphenous vein grafts(SVG) is high due to relatively wide lumen, short and straight course and less influence from cardiac motion. The sensitivity and specificity of patency of SVGs were 92%, 97% respectively in the prospective evaluat on and 100% each in the retrospective evaluation. A false positive and a false negative case are rudimentary errors in the initial learing period. In contrast the analysis of left internal mammary artery(LIMA) graft was difficult due to the inherent small size and the adjacent surgical clips provoking beam-hardening artifact; therefore, the method of combining 3 dimensional reconstruction and flow mode study was important in improving the accuracy of LIMA patency. The sensitivity and specificity of LIMA patency were 100% and 80% in both prospective and retrospective evaluation. Therefore, EBT angiography is an accurate non-invasive diagnostic modality for evaluating the patency of CABG, particularly in SVGs. The accuracy can be improved with the improvement of the EBT and the development of the image reconstruction software.