Myelinated and nonmyelinated nerves: comparison of proton MR properties

The magnetic resonance (MR) relaxation rates of protons were compared in the myelinated and nonmyelinated nerves of the garfish. The long, large olfactory nerve of the garfish, as an easily accessible source of nonmyelinated axons, is uniquely suited for such a comparison. The T1 and T2 measurements revealed distinct and consistent differences between nonmyelinated olfactory nerves and myelinated optic and oculomotor nerves. Comparisons between water content, lipid content, and relaxation rates indicated that the differences in MR properties represent complex differences in the distribution and physical environment of the constituent lipid and water protons.     

Color flow sonography in evaluating the resectability of periampullary and pancreatic tumors

Over the past several years, we have developed a technique to assess the resectability of periampullary and pancreatic tumors using color flow sonography. This is a feasibility study to determine if sonography with color flow imaging can play a role in evaluating patients with periampullary and pancreatic tumors. This study comprises a retrospective analysis of 51 patients referred for color flow sonographic evaluation of resectability of periampullary and pancreatic neoplasm. Scanning was performed with state-of-the-art color flow sonographic systems. Vessels that were touched or occluded by tumor were categorized according to a Pancreatic Color Doppler Score. Other factors affecting resectability (metastasis, enlarged nodes) were recorded. Sonographic findings were correlated with surgical resectability and pathologic findings regarding tumor margins. The color flow study was complete technically (all index vessels visualized) in 49 of 51 patients (96%). In all, 643 of 647 vessels (99.4%) were imaged. Forty-five patients had sufficient surgical, pathologic, or clinical proof to be included in the resectability analysis. All 18 patients with circumferential tumor or vascular occlusion (Pancreatic Color Doppler Score 4 and 5) were found to have unresectable disease. All 10 patients in whom tumor did not touch (Pancreatic Color Doppler Score 0) had negative margins. All 30 patients considered to have unresectable tumors sonographically could not be resected. Patients in this category had one or more of the following: positive pathologic margins, positive nodes, liver metastasis, or not clinically resectable. Six of 15 considered resectable sonographically (40%) were unresectable for cure. Surgeons believed that color flow sonography influenced management in 10 of 45 patients (22% overall). Color flow sonography, a painless, noninvasive, and relatively inexpensive examination, may be an effective screening tool to evaluate periampullary and pancreatic neoplasms for resectability. Our data show that color flow sonography can correctly predict unresectability of periampullary and pancreatic neoplasms. Any future evaluation of imaging and management of periampullary and pancreatic tumors should include color flow sonography.     

Intrauterine growth retardation: evaluation by magnetic resonance. Work in progress

Eleven high risk fetuses between 32 and 37 menstrual weeks gestational age were examined by magnetic resonance (MR) imaging. Serial obstetrical sonograms, birth weights, and serial postnatal examinations were obtained in all subjects. Sagittal MR spin echo images obtained using TR = 0.5 sec and TE = 28 msec were useful for assessing subcutaneous fat. Prospective estimates of fetal fat stores correlated with neonatal outcome better than sonographic measurements of fetal growth parameters or actual birth weight. MR appears to be a safe and useful technique that offers information complementary to obstetrical sonography when IUGR is suspected.     

Tumor thrombosis of the inferior vena cava due to retroperitoneal germ cell tumor

Three patients (2 males and 1 female), aged 17–28 years, with tumor thrombosis of the inferior vena cava due to retroperitoneal germ cell tumor are reported. Diagnostic and therapeutic implications of this condition are discussed.     

Femoral artery compression device for outpatient angiography

To avoid late bleeding from the femoral artery puncture site after outpatient femoral angiography, a compression device was designed to exert continuous pressure over the groin, even when the patient is upright. It has been successfully used in more than 2,000 arterial catheter procedures. The device can also help prevent bleeding in patients who are at increased risk because of hypertension or anticoagulant therapy.     

Spectral and color Doppler sonography.

Color Doppler sonography has become an integral part of modern hepatic sonography. Color Doppler can enhance the conspicuity of focal lesions and bile ducts in jaundiced patients by illuminating normal vessels with flow. Spectral and color Doppler may prove useful in limiting the sonographic differential diagnosis of focal liver lesions. Color flow sonography effectively evaluates pseudoaneurysms, A-V fistulae, collaterals, and flow reversal in portal hypertension, venous clot and tumor invasion, Budd-Chiari syndrome, hereditary hemorrhagic telangiectasis, and many other hepatic vascular lesions. We have found it invaluable in evaluating cirrhotic and liver transplant patients.