No abstract

Three patterns of enhancement of hemangiomas were observed. High signal intensity on T2-weighted images provided complementary information.

Following renal transplantation, patients are often evaluated with ultrasonography (US) or radionuclide imaging to assess renal function and the presence of possible complications. Both modalities are inexpensive, noninvasive, and nonnephrotoxic. A basic understanding of the surgical techniques commonly used for renal transplantation is useful when imaging these patients in order to recognize complications and to direct further imaging or intervention. The most frequent complications of renal transplantation include perinephric fluid collections; decreased renal function; and abnormalities of the vasculature, collecting system, and renal parenchyma. Perinephric fluid collections are common following transplantation, and their clinical significance depends on the type, location, size, and growth of the fluid collection, features that are well-evaluated with US. Causes of diminished renal function include acute tubular necrosis, rejection, and toxicity from medications. Radionuclide imaging is the most useful modality for assessing renal function. Vascular complications of transplantation include occlusion or stenosis of the arterial or venous supply, arteriovenous fistulas, and pseudoaneurysms. Although the standard for evaluating these vascular complications is angiography, US is an excellent noninvasive method for screening. Other transplant complications such as abnormalities of the collecting system and renal parenchyma are well-evaluated with both radionuclide imaging and US.

Sinusoid-phase FLASH imaging is superior to nonequilibrium-phase imaging with MR or CT for the demonstration of hypervascular malignant lesions.

The purpose of the study was to define the magnetic resonance (MR) imaging appearance of adrenocortical carcinoma (ACC) with current MR techniques. Eight patients with ACC underwent high-field-strength MR imaging with the following sequences: axial T1-weighted gradient echo, fat-suppressed T1-weighted spin echo, fat-suppressed T2-weighted spin echo, and gadolinium-enhanced T1-weighted gradient echo and fat-suppressed T1-weighted spin echo. Postcontrast images were also acquired in the sagittal (six patients) and coronal (three patients) planes. Out-of-phase gradient-echo images were obtained in two patients. Lesion morphology, signal intensity features, and presence of metastatic disease were retrospectively evaluated. MR imaging features of ACC included internal hemorrhage (seven of eight patients), central necrosis (seven of eight), and peripheral enhancing nodules (seven of eight). Out-of-phase images in two of two patients demonstrated signal loss compared with in-phase images, which may be a common feature of these tumors. Liver metastases were present in four patients. Consistent MR features of ACC are identified.

Wild edible mushrooms are harvested in the forests of the Pacific Northwest, where both trees and mushrooms grow in the same landscape. Although there has been some discussion about the value of trees and mushrooms individually, little information exists about the joint production of, and value for, these two forest products. Through four case studies, the information needed to determine production and value for three wild mushroom species in different forests of the Pacific Northwest is described, and present values for several different forest management scenarios are presented. The values for timber and for mushrooms are site- and species-specific. On the Olympic Peninsula in Washington, timber is highly valued and chanterelles are a low-value product by weight; timber has a soil expectation value (SEV) 12 to 200 times higher than chanterelles. In south-central Oregon, timber and American matsutake mushrooms have the potential to have about the same SEV. In eastern Oregon, timber is worth 20 to 110 times as much as the morels that grow in the forest. Production economics is concerned with choices about how much and what to produce with what resources. The choices are influenced by changes in technical and economic circumstances. Through our description and analysis of the necessary definitions and assumptions to assess value in joint production of timber and wild mushrooms, we found that values are sensitive to assumptions about changes in forest management, yields for mushrooms and trees, and costs.

Suspected pelvic endometriosis was prospectively evaluated in 31 women with T1-and T2-weighted conventional spin-echo (CSE) magnetic resonance imaging alone and in combination with T1-weighted fat-suppressed (TlFS) and gadolinium-enhanced TlFS (GI-TlFS) spin-echo techniques. Images were grouped for interpretation and comparison as follows: [a) CSE alone, @) CSE/TlFS, and (c) CSE/TlFS/ GI-TlFS. AU patients underwent surgery within 3 months of imaging, and 21 patients were found to have endometriosis: 59 endometriomas (26 large and 33 small) and 51 sites of implants were seen. With CSE images. 23 large and six small endometriomas were detected. With CSE/TlFS images. 25 large and 14 small endometriomas were identified. With CSE/ TlFS/Gd-TlFS images. 24 large and 14 small endometriomas were detected and ill-detlned areas of enhancement were noted in 22 sites throughout the pelvis. These corresponded to endometriotic implants seen at surgery in 14 sites. The sensitivity, specificity. and accuracy, respectively. for the detection of endometriosis were 76%. 60%. and 71% for CSE, 86%. 50%. and 74% for CSE/TlFS, and 81%, 50%. and 71% for CSE/TlFS/Gd-TlFS images.No significant differences (P > .l) between image combinations for correctly identifying patients with and without endometriosis were seen. The difference in sensitivity between CSE and CSE/TlFS and between CSE and CSE/TlFS/Gd-TlFS images for detecting smaU endometriomas was significant (P = .03).

Three rapid T1-weighted gradient-echo techniques for imaging of the liver were compared: fast low-angle shot (FLASH) and section-selective (SSTF) and non-section-selective (NSTF) inversion-recovery TurboFLASH. Ten healthy volunteers were imaged at 1.5 T, with breath-hold images acquired in the transaxial and coronal planes and non-breath-hold images in the transaxial plane. Breath-hold images were evaluated quantitatively and qualitatively, and non-breath-hold images were evaluated qualitatively. FLASH images had significantly higher (P < .001) spleen-liver signal difference-to-noise ratios (SD/Ns) than NSTF and SSTF images. Liver signal-to-noise ratios (S/Ns) were significantly higher (P < .001) on FLASH images than on NSTF and SSTF images. With breath hold, FLASH images were rated as having the highest quality in the axial plane, followed by NSTF and SSTF images. In the coronal plane, NSTF images were rated as having the highest quality. For images acquired during patient respiration, NSTF images had the highest quality and showed the least degradation. The results suggest that FLASH images have the highest SD/N and S/N for liver imaging and have the highest quality in the axial plane. In patients who cannot suspend respiration. NSTF images may be least affected by breathing artifact and provide reasonable image quality.