Neurofibromatosis type 1 (NF1) is the most common of the phakomatoses and has a variety of localized or, more frequently, systemic manifestations throughout the thorax, abdomen, pelvis, and extremities. Classic computed tomographic (CT) findings in NF1 with thoracic involvement include small, well-defined subcutaneous neurofibromas, focal thoracic scoliosis, posterior vertebral scalloping, enlarged neural foramina, and characteristic rib abnormalities due to bone dysplasia or erosion from adjacent neurofibromas. However, more atypical manifestations are occasionally seen, and magnetic resonance (MR) imaging can be useful in equivocal cases. NF1 with abdominopelvic involvement tends to arise in the retroperitoneal, mesenteric, and paraspinal regions; it may be quite extensive and therefore difficult to distinguish from adenopathy at CT. The multiplanar capabilities of MR imaging, particularly with T2 weighting, make this modality helpful in evaluating affected patients and making the diagnosis. The classic peripheral manifestations of NF1 include limb hemihypertrophy, pseudarthrosis, peripheral nerve neurofibromas, and subcutaneous common and plexiform neurofibromas. In some cases of NF1, imaging findings are inconclusive, and biopsy and subsequent pathologic analysis are required. Familiarity with the various manifestations of NF1 in different anatomic locations is important in making the diagnosis and optimizing postdiagnostic treatment.

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We have assessed the effect of 10:1 Iossy (JPEG) compression on six board-certified radiologists' ability to detect three commonly seen abnormalities on chest radiographs. The study radiographs included 150 chest radiographs with one of four diagnoses: normal (n = 101), pulmonary nodule {n = 19), interstitial lung disease (n = 19), and pneumothorax (n = 11). Before compression, these images were printed on laser film and interpreted in a blinded fashion by six radiologists. Following an 8-week interval, the images were reinterpreted on an image display workstation after undergoing 10:1 Iossy compression. The results for the compressed images were compared with those of the uncompressed images using receiver operating characteristic (ROC) analyses. For five of six readers, the diagnostic accuracy was higher for the uncompressed images than for the compressed images, but the difference was not sŸ (P > .1111). Combined readings for the uncompressed images were also more accurate when compared with the compressed images, but this difference was also not significant (P = .1430). The sensitivity, specificity, and accuracy values were 81.5%, 89.2%, and 86.7% for the compressed images, respectively, as compared with 78.9%, 94.5%, and 89.3% for the uncompressed images. There was no correlation between the readers' accuracy and their experience with soft-copy interpretation; the extent of radiographic interpretation experience had no correlation with overall interpretation accuracy. In conclusion, five of six radiologists had a higher diagnostic accuracy when interpreting uncompressed chest radiographs versus the same images modified by 10:1 Iossy compression, but this difference was not statistically significant. Copyright 9 2000 by W.B. Saunders Company T HE EMERGING picture archiving and communication systems (PACS) and digital imaging in general have introduced both opportunities and challenges. Medical images ate now routinely compressed, stored into databases, and transmitted via local area networks. Efficient information management and rapid information transfer are critical cornponents to consider when developing a functional PACS oran effective teleradiology system.The Department of Defense (DOD) deployed the Medical Diagnostic Imaging Support (MDIS) systeta in eight medical centers and 14 teleradiology/ limited PACS sites. The long-term storage archive technique used routinely at those sites is JPEG 10:1 lossy compression. The images are interpreted and are accessible as uncompressed data before longterm storage, where the images are compressed and stored on optical discs, MATERIALS AND METHODS PA CSThe PACS deployed at the Wright Patterson Air Force Base Medical Center in Dayton, OH was one of the first military MDIS systems installed by Lockheed/Martin in 1994. From June 1994 to March 1996, all chest x-ray images were processed by Fuji 7000 computed radiography (CR) readers (Fuji Medical Systems, Stamford, CT) and the uncompressed radiographs were printed on 10-• 14-inch Fuji film. The same images were importe...