Diffusion-weighted MR Imaging of Bone Marrow in the Spine: Differentiations of Metastatic Compression Fracture,Benign Compression Fracture, & Spondylitis

PURPOSE: To determine the findings of diffusion-weighted magnetic resonance (MR) imaging of acute and chronic benign compression fracture, metastatic compression fracture, and spondylitis, and to differentiate between them. MATERIALS AND METHODS: Forty-nine cases with vertebral compression fractures (17 metastatic, 16 acute osteo-porotic, 11 old osteoporotic, 5 acute traumatic) and seven with spondylitis (4 tuberculous, 3 pyogenic) underwent MR imaging. All cases were classified as belonging to one of four groups: A: acute osteoporotic and traumatic, B: metastatic, C: old osteoporotic, or D: spondylitic. For MR imaging, a 1.5-T scanner (Magnetom Vision, Siemens, Erlangen, Germany) was used, and the diffusion-weighted imaging sequence was based on reversed fast imaging with steady-state precession (PSIF) and a relatively low b value of about 150 sec/mm 2. Signal intensity characteristics were evaluated in terms of the contrast ratio (CR) and signal-to-noise ratio (SNR) of bone marrow. RESULTS: Diffusion-weighted MR imaging showed that signal intensity in group A was hypointense to adjacent normal vertebral bodies, but in group B, hyperintensity was noted. In group C, signal intensity was variable, while in group D, hyperintensity was again noted. Diffusion-weighted imaging revealed that in group A, bone marrow CR had a negative value, while in groups B and D, this value was positive (p .01). CONCLUSION: Diffusion-weighted MR imaging revealed that the signal intensity of metastatic compression fracture and spondylitis was hyperintense to adjacent normal vertebral bodies, that of acute benign compression fracture was hypointense, and that of chronic benign compression fracture was variable. This modality is therefore useful for differentiating between metastatic compression fracture, spondylitis and acute benign compression fracture.

Intussusception in Childhood: The Role of Plain Abdominal Radiographs

PURPOSE: The purposes of this study were to evaluate the plain radiologic findings of the childhood intussusception and to evaluate the role of plain abdominal films in predicting the success of air or barium reduction. SUBJECTS AND METHODS: We retrospectively reviewed 140 cases with the diagnosis of intussusception in children. The radiological signs that included soft tissue mass, dilatation of small bowel suggesting obstruction, crescent sign, and target sign were evaluated in terms of frequency. The relationship between radiological findings and outcome of reduction was analyzed. The site of soft tissue mass or crescent sign seen on plain radiographs was correlated with the position of the apex of the intussusceptum seen at the beginning of barium enema. The degree of dilated small bowel was evaluated by calculating the proportion of air-filled small bowel occupying peritoneal cavity and measuring the maximal diameter of dilated bowel lumen. The radiological finding for small bowel obstruction is determined by observation of the degree of small bowel dilatation and/or air-fulid levels. RESULTS: Ninety-two cases out of 140 showed one or more radiographic signs. Two most common signs were soft tissue mass and small bowel obstruction. The success rate of air or barium reduction was significantly lower in patients with most severe degree of dilatation of small bowel and/or more than 7 air-fulid levels on erect view. The suspected location of intussusception on plain radiographs correlated well with the true location of intussusception seen in the first few seconds of barium reduction. CONCLUSION: Plain abdominal radiography is useful in the diagnosis of intussusception and provides helpful informations for the reduction procedure as well as for the exclusion of the contraindications such as bowel perforation.