C. Mark Mehringer

Pulmonary embolism secondary to venous thrombosis of the arm.

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.

Neurochemical alterations in asymptomatic abstinent cocaine users: A proton magnetic resonance spectroscopy study

Cocaine can cause a variety of neuropsychiatric and neurobehavioral complications; however, it is uncertain whether cocaine causes persistent cerebral structural and neurochemical abnormalities in asymptomatic users. We studied 52 African-American men (26 human immunodeficiency virus-negative asymptomatic heavy cocaine users and 26 normal subjects). Ventricle-to-brain ratio (VBR) and white matter lesions (WML) were quantified on magnetic resonance imaging. N-acetyl-containing compounds (NA), total creatine, choline-containing compounds, myo-inositol, and glutamate + glutamine were measured with in vivo proton magnetic resonance spectroscopy, VBR and WML were not significantly different in the cocaine users compared to the normal controls. Elevated creatine (+7%; p = .05) and myo-inositol (+18%; p = .01) in the white matter were associated with cocaine use. NA, primarily a measure of N-acetyl aspartate and neuronal content, was normal. Normal NA suggest no neuronal loss or damage in the brain regions examined in these cocaine users. Therefore, we conclude that neurochemical abnormalities observed might result from alterations in nonneuronal brain tissue.

Transarterial Embolization of Vertebral Hemangioma

PURPOSE The authors retrospectively reviewed their 4-year clinical experience to determine the role of transarterial embolization in the treatment of symptomatic vertebral hemangioma. PATIENTS AND METHODS Eight patients (age range, 12-56 years) underwent a total of 10 embolization procedures; one patient underwent three procedures. The lesions were located between T-5 and L-5, and all patients presented with pain and symptoms referable to the lower extremities. RESULTS Embolization was technically successful in all patients, and no complications were encountered. Six of eight patients underwent surgery within 48 hours of embolization; four of the six showed significant clinical improvement immediately after surgery and on follow-up (average, 34 months). Two patients did not improve postoperatively. Two patients initially underwent embolization as the sole therapy. The first refused surgery and did not improve clinically; the second underwent two embolization procedures without clinical improvement and eventually underwent a third followed by surgery, which resulted in clinical improvement. All patients were hemodynamically stable during surgery, and blood loss was not problematic in any patient. CONCLUSIONS Overall, surgery was an effective treatment for symptomatic vertebral hemangioma and the authors conclude that transarterial embolization of vertebral hemangioma is a safe and efficacious adjunctive procedure to such surgery. However, embolization was not as promising as a sole therapeutic modality in this small group of patients.

Preliminary clinical outcome and imaging criterion for endovascular prosthesis development in high-risk patients who have aortoiliac and traumatic arterial lesions

PURPOSE This report reviews our preliminary experience of prospective treatment of arterial lesions with endoluminal grafts in a Food and Drug Administration (FDA)-approved, investigator-sponsored Investigation Device Exemptions study. The utility and accuracy of various imaging methods, including angiography, cinefluoroscopy, computed tomography (CT), intravascular ultrasonography (IVUS), and duplex scanning, in performing the procedures was also assessed. METHODS Thirty-one patients were evaluated; 17 patients were treated, including 11 with abdominal aortic aneurysms, one with an aortic occlusive lesion, two with iliac artery aneurysms, and three with traumatic arteriovenous fistulas. Twelve of the 14 patients who had aorta and iliac artery lesions were high-risk. The mean follow-up of patients treated was 9 months (range, 6 to 15 months). RESULTS Aortoaortic endoluminal interposition procedures were not successful for treating abdominal aortic aneurysms early in the study (n = 3). Aortoiliac endoluminal bypass, contralateral iliac artery occlusion, and femorofemoral bypass procedures were successful in seven of eight subsequent cases (88%), with no incidence of endoleaks at either the proximal or distal fixation sites using the deployment methods described in this report. The 30-day operative mortality rate on follow-up evaluations for patients who underwent aortoiliac procedures was 14% (two of 14). Other major complications included transient renal failure in three patients that required short-term (two to eight times) dialysis, one arterial perforation and one dissection, and one prolonged intubation. No myocardial infarctions or strokes occurred. After major complications or identification of limitations in the study, the protocol was modified with the approval of the FDA to help avoid the recurrence of the same problems. There were no deaths or complications in the trauma cases. CONCLUSIONS Contrast-enhanced CT (axial images and spiral reconstructions) was the most accurate method to determine candidacy for aortoiliac procedures and to choose the site for deployment of the devices. Angiographic scans were misleading in several patients regarding the critical determinants of patient candidacy and device deployment, particularly regarding the presence of a distal aortic neck. Cinefluoroscopy was used in all patient and was particularly useful for determining the continuity of vascular structures and the anatomy of branch arteries and for enabling precise positioning of stent devices. Determination of fixation sites and assessing dimensional information by cinefluoroscopy and angiography were limited by inaccuracies produced by image magnification, parallax, and uniplanar views. IVUS was used to determine the morphologic features of vascular structures (i.e., calcium, thrombus), to perform real-time observation of the expansion of devices, and to assure firm fixation of balloon-expanded stents before the procedures were completed. Duplex scanning was very helpful in assessing and identifying precisely the location of arteriovenous fistulas before intervention and provided assessment at follow-up intervals. Three-dimensional reconstruction imaging technologies such as spiral CT were particularly helpful for assessing the morphologic features of vascular anatomy before the intervention and at follow-up intervals, whereas 3-D IVUS provided a similar real-time perspective during the procedure.

Spontaneous migration of a bullet in the central nervous system.

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 patients symptoms correlate well with the movement of the foreign body.

Diagnostic imaging of the brain in acquired immunodeficiency syndrome (AIDS)

The central nervous system is commonly involved in acquired immunodeficiency syndrome (AIDS), resulting in a variety of lesions and diseases. They can be divided into the primary effects of human immunodeficiency virus (HIV), opportunistic infections, tumors, and vascular disease. This article is a review of the major imaging findings observed in each disease, with clinical and pathological correlations relevant to the goal of differential diagnosis.

Computed tomographic evaluation of ocular trauma

The CT scans of 10 traumatized patients with demonstrable ocular injuries were reviewed. The CT findings were correlated with the clinical findings in each case. CT manifestations of a variety of ocular and orbital injuries are reported and a systematic approach to the CT evaluation of ocular trauma is presented.

Preoperative balloon occlusion: “the intravascular ligature”

Abstract The resection of cerebral arteriovenous malformations may be difficult or very hazardous when access to the feeding arteries is limited by overlying large draining veins. Properative occlusion of feeding arteries can be performed using detachable flow-directed balloons.

Therapeutic Renal Artery Occlusion with a Detachable Balloon

The use of a new detachable balloon for renal artery occlusion is described. Successful treatment of renal lesions in 5 patients, including 2 tumors, 2 arteriovenous fistulas and 1 case of malignant hypertension with renal failure, is reported.

Sequential Intraluminal Ultrasound Evaluation of Balloon Angioplasty of an Iliac Artery Lesion

This report describes intravascular ultrasound imaging of a localized 81% stenosis in the left common iliac artery of a 52-year-old woman. The lesion was dilated using an 8 mm balloon and was imaged pre- and post-dilatation using arteriography and a 5F, 30 Mhz intravascular ultrasound catheter. The same site was imaged again intraoperatively at two months following the initial procedure using an 8F, 20 Mhz intravascular ultrasound catheter when the patient had a femoropopliteal bypass for continuing ischemia. Intravascular ultrasound imaging allowed accurate, sequential, on-line calculation of the cross-sectional area and volume of the lesion both, acutely and following healing of the site. The morphology of the fractured arterial plaque was clearly defined, demonstrating distribution of calcification, and intraluminal flaps not apparent on arteriography. The case demonstrates the unique potential of intravascular ultrasound in assessing the immediate effect of interventions and evaluating the long-term healing.