Biomedical subjects
Publications and source records attributed to C M Mehringer.
Wallerian degeneration in the corticospinal tract was demonstrated by magnetic resonance (MR) imaging in a patient with Schilder disease. The histochemical stages of myelin breakdown that allow its demonstration by MR imaging are reviewed.
Four cases of spontaneous arteriovenous fistula seen in association with fibromuscular dysplasia of the parent artery are presented. In two patients, the fistula was between the carotid artery and cavernous sinus; in two others, the fistula involved the vertebral artery and paravertebral veins. It is postulated that the angiopathy was responsible for the fistula. Treatment by detachable balloon embolization was successful in each case; however, the presence of the fibromuscular dysplasia made treatment more difficult.
From 1974 to 1986, 148 patients with carotid cavernous fistula (CCF) were evaluated for intravascular therapy. Four patients died from hemorrhage before treatment could be instituted and the CCF closed spontaneously in 5. Therapeutic approaches which resulted in complete occlusion in the remaining 139 cases were transarterial in 118, transvenous in 15 and external compression of the carotid artery and jugular vein in 6. The current treatment of choice of the direct CCF is intravascular embolization using detachable balloons, particulate emboli or liquid adhesive agents to occlude the CCF while attempting to preserve the carotid artery. In 15 patients it was technically too difficult to use the transarterial approach. The patients were therefore treated from a transvenous approach including access via the femoral vein, superior ophthalmic vein, intraoperatively from the inferior petrosal sinus or direct puncture of the cavernous sinus. Embolic agents used included detachable silicone balloons, steel minicoils, particulate emboli and isobutyl-2-cyanoacrylate. In 14 of these 15 patients total obliteration was achieved with marked improvement in symptoms. Complications occurred in 3 patients including perforation of the cavernous sinus resulting in subarachnoid hemorrhage, delayed pontine hemorrhage from subtotal occlusion of the fistula and transient increased proptosis.
Computerized tomographic dimensions of the foramen magnum of 63 achondroplastic individuals were compared to standards established for nonachondroplastic individuals. The size of the foramen magnum in patients with achondroplasia was small at all ages, particularly in those with serious neurologic problems. The data suggest that measurement of the foramen magnum may identify achondroplastic individuals at high risk of developing neurologic complications.
Transcutaneous oxygen tension Ptco2 is directly related to skin oxygen delivery. Regional transcutaneous oximetry ( RTO ) compares peripheral and truncal (Ptco2), yielding a regional perfusion index indicative of local limb perfusion. The relative diagnostic values of RTO , Doppler ankle-brachial pressure ratio (ABR), pulse volume recording (PVR), and toe pulse reappearance time (PRT/2) were studied in 64 limbs of patients with diabetes. These limbs were clinically classifiable into claudication, rest pain, and gangrene groups. Regional transcutaneous oximetry had a higher diagnostic accuracy than ABR (X2 = 27.47, P less than .001), PVR (X2 = 7.54, P less than .01), and PRT/2 (X2 = 10.99, P less than .001). Regional transcutaneous oximetry was universally applicable and the degree of hypoxia observed correlated with clinical symptoms. Significant hypoxia predicted large-vessel angiographic lesions, many of which were reconstructible . Regional transcutaneous oximetry should be the initial noninvasive test in diabetic peripheral vascular disease.
Pulmonary embolism is described as an infrequent complication of axillary and subclavian vein thrombosis. We have reported our recent clinical experience with 14 patients admitted to the Harbor-UCLA Medical Center who had a clinical diagnosis of axillary and subclavian vein thrombosis documented by phlebography of the thrombosed arm. The causes of thrombosis were effort (three patients), trauma (three patients), drug abuse (four patients), underlying neoplastic disease (three patients), and congenital venous malformation (one patient). Pulmonary emboli were diagnosed by arteriogram, ventilation perfusion scans, and arterial blood gas abnormalities in five patients with respiratory symptoms for an incidence of 35.7 percent. Immediate anticoagulation with heparin, then switching to warfarin sulfate after 5 days, was the standard therapy in all patients. Follow-up examinations between 3 and 24 months demonstrated mild postphlebitic syndrome consisting of pain and minimal swelling in two patients. We conclude that pulmonary emboli may be a more frequent complication of axillary and subclavian vein thrombosis than has generally been recognized.
The authors are reporting their experience with arterial digital subtraction angiography to monitor particular intravascular embolization in hypervascular tumors and malformations and angioplasty. Arterial digital subtraction angiography may reduce the time of waiting for regular film developing and subtraction. The smaller amount of contrast material being used in arterial digital subtraction angiography minimizes the discomfort to the patients. It also prevents further renal damage in those patients with poor renal function. The arterial digital subtraction angiography may detect the early warning signs of embolotherapy. From the past experience, the authors have found that arterial digital subtraction angiography should be considered as a better alternative way to performing the particulate embolization and angioplasty than being monitored by conventional angiography.
A traumatic fistula of the left vertebral artery to vertebral and epidural veins with an expanding suboccipital false aneurysm was trapped by endovascular occlusion with detachable balloons. The lesion was not amenable to treatment using the left vertebral artery alone for access. Distal trapping was accomplished by catheterizing the (contralateral) right vertebral artery and placing the balloon retrograde into the distal segment of the left vertebral artery. This maneuver extends the range of vertebral artery lesions for which detachable balloons, either alone or as an adjunct to operation, can be used.
Regional transcutaneous oximetry is a new, noninvasive diagnostic technique for the investigation of peripheral vascular disease (PVD) that uses differences in limb and trunk transcutaneous PO2 to assess the adequacy of local perfusion. The application of such measurements would be of great importance in diabetes, in which limb ischemia is commonly difficult to assess. A group of diabetic subjects with symptomatic PVD was studied with regional oximetry, Doppler-assisted blood pressure measurements, and arteriography. Doppler studies correlated poorly to symptom grade and angiographic data, while oximetry clearly demonstrated limb hypoxia under the functional conditions appropriate to the patients' clinical symptomatology. The superiority of oximetry to Doppler studies was highly significant (X2 = 12.64, P less than 0.001). Regional transcutaneous oximetry should therefore be the noninvasive diagnostic test of choice in the initial evaluation of the diabetic limb for PVD. Because of its dependence on the adequacy of local oxygenation, transcutaneous oximetry is a powerful tool for investigation of the pathophysiology of PVD and will, in the future, have wide-ranging applications to the diagnosis and therapy of PVD.
Three cases of congenital lipomatosis involving the thoracic region posteriorly are presented delineating the natural history of the disease and depicting underlying bone and soft tissue changes. The rib widening and pleural thickening appear to be related to increased intercostal vascularity feeding the overlying tumor, as delineated by angiography. This entity is not described in the radiologic literature.
An example of spontaneous migration of a metallic foreign body within the subarachnoid space is illustrated. An intracranial bullet is shown to move within the cisterns of the posterior fossa and then down the subarachnoid space of the spinal canal. The patient's symptoms correlate well with the movement of the foreign body.
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Radiologic imaging techniques play an important role in the diagnosis and management of neurocysticercosis. Cysticercal involvement of the central nervous system can be classified as parenchymal, ventricular, meningo-cisternal, spinal, and mixed, depending upon the site of involvement. Computerized tomographic scanning has replaced most of the previously used techniques for assessing parenchymal disease and diagnosis has been greatly improved. Ventriculography and myelography are still useful in cases of intraventricular and spinal disease respectively.
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We examined a patient with an orbital stab injury with fatal intracranial extension in whom the initial emergency examination did not reveal the extent of damage. Ophthalmologic consultation showed an afferent pupillary defect (Marcus-Gunn pupil), which prompted radiologic studies. Orbital tomograms and computerized tomography demonstrated an optic canal fracture and penetration to the contralateral right ventricle. Diabetes insipidus and thermal irregularity developed, and death occurred seven days later.
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