Ultrasonography has proved a valuable tool for the detection of enlarged lymph nodes; however, differentiation between benign and malignant nodal disease remains a problem. High-frequency probes with improved spatial and contrast resolution display superficial nodes to advantage and also show the internal structure of the nodes. Ninety-four superficial nodes in patients with suspected nodal disease were examined by using 7.5-MHz probes to evaluate longitudinal-transverse diameter ratio (L/T), the central hilus, cortical widening, and size. Histologic diagnosis was obtained after sonographic examination in 73 nodes (five reactive nodes, 35 primary nodal malignancies, and 33 nodal metastases). The remaining 21 nodes regressed after either antibiotic or no therapy. Marked differences were observed among the proportions of benign and malignant nodes in terms of L/T, hilus, and cortex; the latter two structures, however, must be interpreted together. Eccentric cortical widening was seen in only malignant nodes. The distribution of nodal size was not significantly (P greater than .1) different for benign and malignant nodes. No differences were observed between primary and secondary nodal malignancies. The sonographic criteria evaluated in this study assist in the differentiation of benign from malignant superficial lymph nodes.

Gd-EOB-DTPA is an efficient, diagnostically useful, and safe contrast agent.

No abstract

Our objective was to study Gd-EOB-DTPA for the characterization of focal liver lesions by means of dynamic MR imaging. A double-blind and randomized dose-ranging phase-2 clinical trial was performed in 31 patients (liver metastases n = 23, hepatocellular carcinoma n = 4, and hemangioma n = 4) at a field strength of 1.0 Tesla. Gd-EOB-DTPA (Schering AG, Berlin, Germany) was administered as an IV bolus (12.5, 25, or 50 micromol/kg body weight) with dynamic T1-weighted MRI during the distribution and cellular uptake of the contrast agent at multiple time points up to 45 min post contrast. Dynamic changes in tumor signal intensity, tumor-liver contrast, enhancement patterns, side effects, and adverse events were evaluated. Monitoring of vital signs revealed no significant changes during bolus injection of Gd-EOB-DTPA. Liver metastases demonstrated an inhomogeneous uptake of Gd-EOB-DTPA during the distribution phase with a washout effect on delayed images > 3 min and highest tumor-liver contrast 20 and 45 min post contrast. Hepatocellular carcinomas showed prolonged enhancement as compared with metastases and hemangiomas. Hemangiomas exhibited an early peripheral-nodular enhancement with subsequent partial or complete filling, persisting enhancement < 10 min following injection of Gd-EOB-DTPA, and delayed washout as compared with liver metastases. Initial clinical experience suggests that Gd-EOB-DTPA as a bolus injectable hepatobiliary MR contrast agent may offer useful features for the characterization of focal liver lesions.

Static and dynamic magnetic resonance imaging studies were performed in 69 patients with bone and soft-tissue tumors. T1-weighted spin-echo (SE) imaging after intravenous administration of gadolinium diethylenetriaminepentaacetic acid (DTPA) improved the differentiation of necrotic from viable areas; the contrast-to-noise ratio (C/N) between tumor and muscle was an average of 44% lower compared with that in T2-weighted SE imaging. The C/N between tumor and bone marrow or fatty tissue was 43% and 37% lower, respectively, compared with that in nonenhanced T1-weighted SE imaging. Dynamic changes of signal intensity (SI) after Gd-DTPA enhancement were assessed with fast low-angle shot imaging. Of malignant tumors, 84.1% exhibited slopes higher than 30% per minute; 72% of benign tumors showed slopes lower than 30% per minute. The dynamic technique enabled assessment of the malignant potential of a tumor with some overlap (accuracy, 79.7%). Necrotic areas and peritumorous edema showed significantly lower and more gradual increases in SI than adjacent neoplastic tissue.

No abstract

Resovist is a safe contrast agent, and a dose of 8 mumol Fe/kg is sufficient to enhance detection of focal liver lesions at T2-weighted fast SE MR imaging.

In 15 osteosarcomas and six Ewing sarcomas, response to preoperative chemotherapy was assessed with magnetic resonance (MR) imaging without and with gadolinium diethylenetriaminepentaacetic acid (DTPA) enhancement and with dynamic Gd-DTPA studies, and the results were compared with the scintigraphic findings. All studies were obtained prior to and following preoperative chemotherapy. Static MR imaging was of little value for assessment of response; reduction in signal intensity within soft-tissue masses on the T2-weighted spin-echo images indicated response with a sufficient degree of accuracy (71%) but low sensitivity, whereas an increase in signal intensity after Gd-DTPA administration indicated zones of viable tissue with low specificity. With three-phase skeletal scintigraphy, the findings in the perfusion and blood-pool phases were of no value, whereas the findings in the osseous phase allowed the prediction of response with an accuracy of 73.7%. Of all techniques employed, dynamic MR imaging had the highest degree of accuracy (85.7%) and was superior to scintigraphy, particularly in patients who were receiving intraarterial chemotherapy.