No abstract

This study was designed to evaluate pulse sequences and patient positioning for MR imaging of silicone breast implants in patients. One hundred forty-three patients (281 silicone implants) underwent imaging over a 21-month period. The combination of a T2-weighted fast spin echo technique (SE), T2-weighted fast SE with water suppression, and T1-weighted SE with fat suppression is recommended to reliably differentiate silicone from other breast tissues and to identify intracapsular and extracapsular ruptures or leaks. Seventy of the 143 patients underwent removal of their silicone implants. The sensitivity for detection of silicone implant rupture was 76%, with a specificity of 97%. Positioning the patient prone improved image quality.

Desmoplastic fibroma (DF) of bone is a rare, nonmetastasizing but locally aggressive tumor that has been discussed infrequently in the radiology literature. The radiographs from 107 previously published cases of DF and seven cases from the authors' institution were analyzed to better understand and define its radiographic characteristics. DF was most common in the mandible, pelvis, and femur. A geographic pattern of bone destruction, with a narrow zone of transition and nonsclerotic margins, was seen in 80 (96%) patients with intraosseous DF for whom radiographs were available (83 patients). Internal pseudotrabeculation was seen in 76 (91%). Although widening of the host bone due to gradual apposition of periosteal new bone was common, occurring in 74 (89%) patients, distinct periosteal new bone occurred in only two (2%) patients with DF of intraosseous origin. The cortex was breached in 23 (28%) patients. Three cases of DF arising in the periosteum were identified and were differentiated radiographically from desmoid tumors of intraosseous or soft-tissue origin.

Traumatic injury to the knee remains a diagnostic and therapeutic challenge. Magnetic resonance imaging (MRI) has been applied to musculoskeletal pathoanatomy and has been shown to be an effective tool for definition and characterization of knee pathology. A systematic approach is taken to establish anatomical and pathoanatomical correlations, as well as the role of MRI in the management of knee injuries. Imaging was performed at the UCLA Medical Center using a permanent magnet system and a combination of solenoidal surface coils and thin-section, high-resolution scanning techniques. Images depict structural anatomical and spatial details of the knee that correlate well with corresponding cadaveric cryosections. To determine pathoanatomical correlations and the efficacy of MRI, 105 patients with preoperative diagnoses of meniscal tears, anterior and posterior cruciate ligament tears, tibial plateau fracture, and patella and quadriceps injuries were imaged. Results indicated that for the medial meniscus MRI demonstrated a 95.7% sensitivity, 81.8% specificity, 90% accuracy, 88.2% positive predictive value (PPV), and 93.1% negative predictive value (NPV). Imaging of the lateral meniscus demonstrated a 75% sensitivity, 95% specificity, 91% accuracy, 80% PPV, and 94% NPV. MRI of the ACL revealed 100% sensitivity, specificity, accuracy, positive and negative predictive values. MRI is a noninvasive tool which uses no ionizing radiation and can accurately define and characterize anatomy and pathoanatomy. This study indicates that MRI in conjunction with clinical evaluation can contribute to treatment decision-making processes and assist in preoperative planning. An algorithm demonstrating the potential clinical use of MRI is presented.

Pulsing electromagnetic fields of low frequency and strength have been inductively coupled across skin, directly to bone, to enhance the repair of canine osteotomies. The induced voltage field in bone appears to increase the organization and strength of the repair process at 28 days after "fracture."