Treatment of cerebral arteriovenous malformations: combined neurosurgical and neuroradiologic approach

Experience with 31 intraoperative embolizations performed on 23 patients is reported. The procedure involves the direct injection of embolic material into the main arterial feeders during craniotomy. The combined effort involves the exposure of the lesion at craniotomy, standard arteriotomy, and fluoroscopically monitored intravascular infusion of contrast material followed by the injection of bucrylate (IBCA, Ethicon, Somerville, NJ) mixed with tantalum or Pantopaque into the feeding vessels and into the interstices of the malformation. It was concluded that the procedure significantly diminishes operating time and blood loss for the lesions that were subsequently resected. Fluoroscopy coupled with high-quality stop-frame videotape recording allows a detailed study of the flow characteristics of the malformation so that polymerization time can be regulated appropriately. Follow-up varied from 3 months to 4 1/2 years. There were two deaths related to the procedure and one additional complication of cortical blindness that partially resolved. None of the survivors rebled. Most of the survivors improved.     

Color Doppler US imaging during pediatric neurosurgical and neuroradiologic procedures

Experience with color Doppler imaging (CDI) during 16 pediatric intraoperative and one percutaneous neuro-radiologic procedures was reviewed to assess whether CDI increased the success rate or decreased the procedure time, thus contributing substantially to procedure performance. Intraoperative CDI was used to rapidly identify abnormal vessels or displacement of normal vessels and correlated with preoperative studies. In six cases (four vascular malformations, one mycotic aneurysm, and one hamartoma), surgical resection was altered on the basis of flow information obtained. In one case of percutaneous embolization of a Galenic malformation, CDI provided information contributing to the cessation of the procedure. In six cases (debulking of three gliomas, resection of one vascular malformation, and two biopsies of nonneoplastic conditions), information was added but did not alter the surgical approach. In the remaining four cases (three cerebrospinal fluid drainage procedures, one posterior fossa decompression), no additional information was obtained. Consultation among the ultrasound staff, neuroradiologists, and neurosurgeons before the operative procedure maximized the usefulness of CDI, thus aiding in the success of surgery.     

Aberrant right subclavian artery: further observations

One hundred one posteroanterior and 89 lateral chest radiographs were reviewed of patients with proven aberrant right subclavian artery. The patients were 17-96 years old. Three findings were noted on the posteroanterior radiograph: an oblique edge extending to the right from the aortic knob (60%); demonstration of the vessel through the lucency of the tracheal air column (43%) with sharp margins (29%) or as a tubular opacity without sharp margins (14%); and a "mass" effect at the medial right clavicular area (32%). Three findings were noted on the lateral radiograph: retrotracheal opacity (79%), aortic arch obscuration (62%), and posterior tracheal imprint (49%). Two of these findings (tubular opacity and mass effect) are reported as new observations in patients with aberrant right subclavian artery.     

Improving lesion detection and visualization: implications for neurosurgical planning and follow-up

Contrast-enhanced magnetic resonance (MR) imaging is considered the most sensitive method for detecting tumors in the central nervous system (CNS). The primary objective is to improve lesion detection, delineation, and characterization (benign or malignant) in order to more accurately define the location, extent, and type of disease and the appropriate treatment option for improved patient outcome (surgical intervention, radiation therapy or cytotoxic chemotherapy). This article reviews the various types of tumor occurring in the brain and the specific role of contrast-enhanced MR imaging for the evaluation of these tumors. Emphasis is placed on the value of contrast-enhanced MR imaging in the evaluation of primary intra-axial brain lesions and how high relaxivity contrast agents such as MultiHance (Bracco Imaging, Milan, Italy) might improve detection, treatment planning, and follow-up.     

Improving lesion detection and visualization: implications for neurosurgical planning and follow-up

Contrast-enhanced magnetic resonance (MR) imaging is considered the most sensitive method for detecting tumors in the central nervous system (CNS). The primary objective is to improve lesion detection, delineation, and characterization (benign or malignant) in order to more accurately define the location, extent, and type of disease and the appropriate treatment option for improved patient outcome (surgical intervention, radiation therapy or cytotoxic chemotherapy). This article reviews the various types of tumor occurring in the brain and the specific role of contrast-enhanced MR imaging for the evaluation of these tumors. Emphasis is placed on the value of contrast-enhanced MR imaging in the evaluation of primary intra-axial brain lesions and how high relaxivity contrast agents such as MultiHance (Bracco Imaging, Milan, Italy) might improve detection, treatment planning, and follow-up.     

Radionuclide angiography in suspected acute cholecystitis: further observations

Radionuclide angiography (RNA) and cholescintigraphy were performed prospectively in 300 patients with suspected acute cholecystitis (AC). Of 79 patients with positive RNA, 63 had AC (80%). Positive RNA was seen in 23 of 26 cases with gangrenous AC (88%) while 12 of the 26 had a positive "rim" sign (46%). All 12 patients with a positive "rim" sign had positive RNA. The "rim" sign may be caused by increased perfusion. Five of 6 patients with positive RNA and "obstructive" pattern had AC (83%). Patients with negative RNA and positive cholescintigraphy had a positive predictive value of 54% (31/57), while those with positive RNA and positive cholescintigraphy had a positive predictive value of 85% (57/67). RNA showed increased perfusion to nonbiliary pathology such as liver abscesses and pyelonephritis. Positive RNA increases the predictive value of cholescintigraphy and may be useful to shorten cholescintigraphic examinations.     

Computed tomography of pericardial masses: further observations and comparison with echocardiography

Eight patients with surgically proven primary intrapericardial masses were evaluated over the past 3 years using a variety of radiologic tests. Dynamic CT prospectively identified the masses in all eight patients, esophagography was positive in four of five patients, chest radiography was prospectively positive in one of eight patients, and echocardiography identified a mass in only one of seven patients. Furthermore, precise CT localization of the masses proved important in surgical management of these patients, suggesting in several instances the need for cardiopulmonary bypass. Although echocardiography is the modality of choice in evaluating potential pericardial effusion, CT should be the preferred diagnostic test for suspected intrapericardial mass lesions.     

Cerebral hemodynamics in infants undergoing extracorporeal membrane oxygenation: further observations

Intracranial Doppler ultrasonographic examinations were performed on 64 infants treated with extracorporeal membrane oxygenation (ECMO). Serial studies were performed on the anterior cerebral artery in 55 infants before and during ECMO bypass, and on the middle cerebral arteries (MCAs) and internal carotid arteries (ICAs) on an additional nine infants. The onset of ECMO was associated with changes in character of pulsatile flow, direction of flow, and mean blood-flow velocity. Pulsatility decreased in all patients, and mean blood-flow velocity increased in 73% of patients (mean change from baseline, 87%). Despite retrograde flow in the right ICA in five of nine infants, antegrade flow to the right MCA was preserved in all cases. We found no correlation between alterations in mean blood-flow velocity and overall mortality, frequency of intracranial hemorrhage, and neuro-developmental outcome. These data suggest that wide variations in cerebral blood flow occur with ECMO therapy, and that these changes appear to be well tolerated.     

The bile ducts after a fatty meal: further sonographic observations

The sonographic appearance of the response of the common hepatic duct to physiologic stimulation by a fatty meal was assessed in 131 patients referred because of right upper quadrant symptoms or abnormal liver chemical studies. In the determination of the presence or absence of biliary obstruction, the sensitivity of the examination was 84%, the accuracy of a positive test was 84%, and the accuracy of a negative test was 93%. This test proved helpful in several circumstances: equivocal duct caliber (6-10 mm); abnormal caliber (6-14 mm) with normal laboratory values; normal caliber duct with abnormal laboratory values; persistent question of cholelithiasis or asymptomatic pancreatic duct dilatation. Measurements of bile duct caliber alone may be insufficient to ascertain the presence of bile duct obstruction and fatty meal stimulation significantly improves diagnostic accuracy.     

Adjuvant intra-arterial lidocaine in aortofemoral arteriography: some further observations.

It has been shown that lidocaine administered as a bolus intra-arterially immediately prior to contrast media injections significantly decreased the pain experienced from aortofemoral arteriography. Some researchers have advocated mixing 2 mgm of lidocaine with each ml of contrast agent rather than giving it as a bolus prior to the contrast agent. In a randomized study of 30 patients, the authors demonstrated that both methods are equally effective in decreasing the pain from aortofemoral arterography and that mixing the lidocaine with the contrast agent is the easier method.     

Early-onset combined methylmalonic aciduria and homocystinuria: neuroradiologic findings

BACKGROUND AND PURPOSE: Combined methylmalonic aciduria and homocystinuria (MMA-HC) is caused by impaired hepatic conversion of dietary cobalamin to methylcobalamin and adenosylcobalamin, resulting in decreased activity of methylmalonyl-CoA mutase and methionine synthase. Patients with the early-onset variety present within 12 months of age with severe neurologic, hematologic, and gastrointestinal abnormalities. We describe the neuroradiologic features of early-onset MMA-HC and discuss related pathophysiological mechanisms. METHODS: Twelve infants with hypotonia, failure to thrive, poor feeding, and hematologic abnormalities were diagnosed with MMA-HC on the basis of a typical plasmatic and urinary metabolic profile and enzyme activity in fibroblastic cultures. Complementation studies were performed in two cases, and yielded a CblC result. MR imaging was performed at presentation in four cases and later in the others. All patients showed prompt biochemical improvement with intramuscular hydroxocobalamin administration, and most had moderate neurologic improvement. RESULTS: Diffuse supratentorial white matter edema and dysmyelination was the typical MR picture at presentation, whereas white matter bulk loss characterized later stages of the disease. Nucleocapsular areas of gliosis were an additional finding in one case. One patient had tetraventricular hydrocephalus at presentation. CONCLUSION: White matter damage is probably caused by reduced methyl group availability and nonphysiological fatty acids toxicity, whereas focal gliosis results from homocysteine-induced toxicity to the endothelium. Hydrocephalus may result from diffuse intracranial extracerebral arterial stiffness, known as reduced arterial pulsation hydrocephalus. MR imaging features at presentation and at follow-up are nonspecific.     

Rupture of echinococcal cysts: diagnosis, classification, and clinical implications

The authors classify rupture of echinococcal cysts into three types: contained, communicating, and direct. Contained rupture occurs when only the parasitic endocyst ruptures and the cyst contents are confined within the host-derived pericyst. When cyst contents escape via biliary or bronchial radicles that are incorporated in the pericyst, the rupture is communicating. Direct rupture occurs when both the endocyst and the pericyst tear, spilling cyst contents directly into the peritoneal or pleural cavities or occasionally into other structures. Communicating and direct forms have more serious clinical implications than contained rupture, but even contained rupture should have prompt surgical attention to prevent it from developing into one of the other forms. Untreated communicating rupture of a liver cyst can lead to obstruction of the biliary system with a 50% mortality rate. Direct rupture may cause anaphylaxis, and it should be managed surgically, possibly with adjunctive treatment with antihelminthic drugs to decrease the possibility of metastatic hydatosis.     

Isolated cysticercal infestation of extraocular muscles: CT and MR findings.

PURPOSEWe sought to document the appearance of isolated cysticercal infestation of single extraocular muscles on MR and CT studies, and to compare these findings with results of histopathologic examination.METHODSSix MR and three CT examinations of the orbits of six patients were reviewed. Histopathologic confirmation of the diagnosis was available in three patients, and response to specific medical therapy was available in one. In all, the imaging findings were considered highly suggestive of cysticercal infestation.RESULTSTypically, the affected extraocular muscle showed fusiform enlargement of its belly and contained a well-defined, spherical cyst with a nodule attached to its wall. The mural nodule was identified in all six cases with varying degrees of visibility. It was best seen on the CT examinations and in all cases in which contrast material had been administered. The nodule and the enlarged muscle showed intense enhancement on the contrast-enhanced studies. Imaging studies of the brain showed no evidence of cerebral cysticerci in any of the patients.CONCLUSIONThe MR and CT appearance of isolated infestation of single extraocular muscles by the larva of the pork tapeworm Taenia solium is quite characteristic and often diagnostic of this condition.     

Serial MR imaging of pineal cysts: implications for natural history and follow-up

OBJECTIVE: The purpose of this study was to examine the frequency of change in size of pineal cysts on serial MR studies. MATERIALS AND METHODS: Thirty-two patients (19 females, 13 males) with a diagnosis of pineal cyst at any time who underwent brain MR imaging more than once in a period of at least 6 months were identified by computerized search of radiology reports. Four patients underwent MR imaging to follow up pineal cysts, whereas the remaining patients were imaged for a variety of indications, including intracerebral neoplasms. Measurements of maximal cyst dimension on both initial and latest follow-up studies were obtained in all patients, and cyst volumes were calculated in 23 patients. RESULTS: Length of follow-up ranged from 6 months to 9 years. All cysts were considered incidental and none were treated. Maximal cyst dimensions ranged from 0.5 to 2.2 cm. On average, there was no significant change in cyst volume. The maximal dimension of the cyst did not change in 24 (75%) of 32 patients. Two cysts resolved completely on follow-up, three cysts decreased by 2-4 mm, two cysts enlarged by 2-3 mm, and one cyst formed and grew to 1.2 cm. CONCLUSION: Whereas the size of pineal cysts as a whole remained unchanged on serial MR studies, cysts may either form or involute in individual patients. Small increases in cyst size did occur but were not associated with specific clinical findings. These findings suggest that typical pineal cysts may be followed up on a clinical basis alone rather than on imaging.     

Supratentorial arachnoid cyst and associated subdural hematoma: neuroradiologic studies

CT and MR images of 8 patients with supratentorial arachnoid cyst complicated by subdural hematoma were studied and compared with those of 8 patients who developed nontraumatic subdural hematoma without arachnoid cyst. Of the 8 patients with supratentorial arachnoid cyst, CT and MR disclosed temporal bulging and/or thinning of the temporal squama in all 6 patients with middle fossa arachnoid cysts, and the thinning of the calvaria was evident in another patient with a convexity cyst. Calvarial thinning at the site corresponding to interhemispheric arachnoid cyst was clearly depicted on coronal MR images. In contrast, none of the 8 young patients with nontraumatic subdural hematoma without arachnoid cyst had abnormal calvaria. Temporal bulging and thinning of the overlying calvaria were identified as diagnostic CT and MR features of arachnoid cyst with complicating intracystic and subdural hemorrhage. Radiologists should be aware of this association and should evaluate the bony structure carefully. Correspondence to: M. Ochi