Glioblastoma: catheter techniques for isolated chemotherapy perfusion

Techniques have been developed for isolated perfusion of chemotherapeutic agents in patients with glioblastoma. Three catheters that facilitate crossing the carotid siphon have been developed; two are based on an everting or toposcopic principle, and one uses microjets for deflectability and improved mixing. Blood from the ipsilateral jugular vein is aspirated at high volumes (300 ml/min) for extracorporeal circulation through an adsorption column (for recovery of carmustine) or dialysers (for recovery of cisplatin). Preliminary experience in 10 patients suggests that high doses of chemotherapeutic agent can be administered using these catheters, with reduced retinal and systemic toxicity.     

Magnetic resonance imaging of prosthetic heart valves

To evaluate the safety of magnetic resonance (MR) imaging of prosthetic heart valves, nine different synthetic and tissue valves were studied ex vivo. Deflection was measured in 0.35-tesla (T) and 1.5-T superconducting magnets and at the edge of the bore of a 2.35-T electromagnet in field gradients of 5, 1.1, and 6.3 mT/cm, respectively. No valve deflected in the 0.35-T magnet; six synthetic valves deflected 0.25 degrees-3 degrees in the 1.5-T magnet; all valves deflected 1 degree-27 degrees at the edge of the 2.35-T magnet. Each valve was then submerged in a vial of water and the temperature was measured immediately before and after each of two spin-echo imaging sequences in the two superconducting magnets. No significant temperature rise followed exposure in either magnet. Image distortion varied from negligible to severe in both imagers; magnitude of distortion paralleled magnitude of deflection. These data suggest that patients with present-day prosthetic heart valves can be safely imaged in present-day MR imagers and that prosthesis-induced artifacts will not interfere with interpretation in most instances.     

Deep vein thrombosis: significant limitations of noninvasive tests

Impedance plethysmography (IPG) has a reputed sensitivity of 95% in the detection of proximal, clinically significant deep venous thrombosis (DVT). A review of the radiologic studies of 100 consecutive patients who underwent both venography and IPG showed venographic evidence of proximal DVT in 40 patients. The IPG was negative in 15 (38%) of these 40 cases. The specificity of the IPG was 83%. The predictive value of a negative study, with this 40% prevalence of DVT, was 77%. These disturbing results indicate a continuing role for venography in the workup of DVT.     

Echogenic vasculature in the basal ganglia of neonates: a sonographic sign of vasculopathy

The vessels that supply the basal ganglia and thalami are not normally conspicuous on the cranial sonograms of neonates. Twelve neonates with abnormally echogenic or "bright" vessels on cranial sonograms were studied. Records of these 12 patients were reviewed and were correlated with the neuropathologic findings available in four. The clinical diagnoses were cytomegalovirus infection (five patients), rubella (two patients), congenital syphilis (one patient), and trisomy 13 syndrome (three patients). No diagnosis was made in one infant. At neuropathologic examination, perforating medium-sized arteries to the basal ganglia and thalami had thickened hypercellular walls, with deposits of amorphous basophilic material in three infants. Results of computed tomography and radiography of brain sections were normal in these areas. Sonography is helpful in detecting early noncalcific inflammation and mineralization in vasculitis. Although nonspecific, these findings should alert the physician to the possibility of congenital infection or chromosomal abnormality.