Use of radio-frequency field gradients to image blood flow and perfusion in vivo

A magnetic resonance imaging method based on the use of radio-frequency (RF) magnetic field gradients to detect molecular motion has been combined with GRASS (gradient-recalled acquisition in a steady state) imaging to detect arterial blood flow in vivo. The method has been used to selectively attenuate signals from flowing blood in the human finger. Attenuation of signals from arterial blood was greatly reduced when blood flow was decreased with the application of a tourniquet. This result demonstrated the sensitivity of the technique to the rate of blood flow. RF gradient coils can be used to generate very high RF gradients with submicrosecond rise times and minimal eddy currents. Therefore, this method may prove useful for imaging very slow, nonuniform flow through capillary beds and in the extravascular space.     

Biochemical analysis of specific histamine HI and H2 receptors on lymphocytes

It is increasingly clear that histamine mediates a variety of lymphocyte functions. Further understanding of these mechanisms requires a method for the analysis of histamine membrane receptors on the lymphocyte surface. We report now a biochemical technique for the identification and quantitation of specific histamine H1 and H2 receptors of lymphocytes. The method can be performed on small numbers of formaldehyde-fixed cells. The data this assay yields, together with that resulting from the flow cytometric analysis of histamine receptor distribution (a technique we have previously described), will be a powerful tool in the study of histamine mediation of lymphocyte function.     

Primary lung cancer: biodistribution and dosimetry of two In-111- labeled monoclonal antibodies

This study was undertaken to measure the biokinetics and organ dosimetry of indium-111-labeled monoclonal antibodies (MoAbs) with a whole-body gamma camera imaging technique. Twenty patients with primary lung cancer were studied with two different MoAb agents (anti-carcinoembryonic antigen ZCEO25 and antiadenocarcinoma LA20207). Imaging was performed at 1, 24, 72, and 144 hours after injection. Scintigraphic whole-body retention was verified by means of comparison with the results from in vitro counting of excreta. Organ retention was verified in an abdominal phantom. The MoAb cleared slowly from the heart and lungs, the brain and spleen showed no clearance, and the liver showed increased activity over the 6-day period. Dosimetry for ZCE025 showed a dose to the liver of 1.3 rad/mCi (0.36 mGy/MBq); heart, 1.5 rad/mCi (0.40 mGy/MBq); spleen, 1.1 rad/mCi (0.29 mGy/MBq); total body, 0.49 rad/mCi (0.13 mGy/MBq); and testes, 0.39 rad/mCi (0.11 mGy/MBq). The dosimetry for LA20207 was similar.     

CT-SPECT fusion to correlate radiolabeled monoclonal antibody uptake with abdominal CT findings

To enhance the information provided by computed tomography (CT) and single photon emission computed tomography (SPECT) performed with radiolabeled, anti-carcinoembryonic antigen monoclonal antibody (MoAb), the authors performed fusion of these types of images from eight subjects with suspected colorectal adenocarcinoma. Section thickness and pixel size of the two studies were matched, coordinates of corresponding points from each study were identified, and CT sections were translated, rotated, and reprojected to match the corresponding SPECT scans. The CT-SPECT fusion enabled identification of anatomic sites of tumor-specific MoAb accumulation in four cases, showed non-specific MoAb accumulation in two, and helped confirm information only suggested by the two studies separately in one.     

Percutaneous cholecystolithotomy: preliminary experience and technical considerations

Surgical cholecystectomy is associated with a high morbidity and mortality in elderly patients with acute calculous cholecystitis and underlying cardiac or pulmonary disease. Currently there are few alternatives for treating these patients. The authors have used percutaneous cholecystolithotomy in 11 such high-risk patients for definitive treatment of gallbladder calculi. In all 11 patients all stones were successfully removed from the gallbladder and cystic duct. The entire procedure--from initial tube placement to final tube removal--lasted 17-40 days (mean, 21 days). There were two complications: one minor--local wound infection--and one major--bile peritonitis with eventual death. Percutaneous cholecystolithotomy is an effective alternative therapy for acute calculous cholecystitis in elderly, debilitated patients.     

Late intestinal strictures following successful treatment of necrotizing enterocolitis

Between 1975 and 1992, in 16 infants (14%) out of 113 neonates with previous necrotizing enterocolitis (NEC) a total of 25 intestinal strictures had to be treated. Four (16%) were found in the ileum and 21 (84%) in the colon, and in 50% multiple strictures were present. In these 16 patients initial treatment for acute NEC included conservative treatment in 5, primary resection and enterostomies in 6 and proximal diverting enterostomies in 5. Therefore, the incidence of late strictures was 11% after conservative therapy, 11% after primary resection and 55% after primary proximal diverting enterostomies. An average of 49 days elapses between the recovery from NEC and the diagnosis of late strictures in conservatively treated patients. After initial surgical treatment, late strictures were detected on contrast studies on an average of 80 days. In pathologic specimens, marked fibrosis in the submucosa was consistently present in all strictures, whereas inflammatory changes in the mucosa, disruption or hypertrophy of the muscle layers or absence of ganglion cells were seen less frequently. All strictures were resected and primary end-to-end anastomosis was performed. But despite the development of late intestinal strictures, bowel preservation was improved after initial restrictive surgical therapy and aggressive medical treatment.