Colleen M. Costelloe

Purpose: To evaluate the feasibility of fast Dixon whole‐body (WB) magnetic resonance imaging (MRI) for detecting bone and liver metastasis in clinical patients and to compare its performance with skeletal scintigraphy (SS) for detecting bone metastases using reference imaging with >1 year follow‐up as the gold standard.Materials and Methods: Twenty‐nine patients with bone metastases prospectively underwent WB MRI and SS. WB MRI included coronal T2, axial T1 with and without intravenous gadolinium (including triphasic liver sequences), and axial diffusion‐weighted imaging, plus spinal sagittal postcontrast T1‐weighted images. The skeleton was divided into 16 segments. Reviewers blinded to other images identified up to five lesions per segment and rated them using a five‐point confidence scale for metastatic disease. Sensitivities and specificities were compared using the McNemar test.Results: The sensitivity of WB MRI and SS in detecting bone metastases was 70.8% and 59.6% (P = 0.003), respectively; specificity was 89.1% and 98.7% (P < 0.0001). WB MRI detected all livers with metastases (n = 8). One focal nodular hyperplasia was classified as a metastasis on WB MRI.Conclusion: Fast Dixon WB MRI is feasible in clinical patients, highly specific, and more sensitive than SS in detecting bone metastases, and can detect metastases of the liver. J. Magn. Reson. Imaging 2012;399‐408.

OBJECTIVE. Inversion recovery has been used to correct the loss of CSF and tissue contrast at 3 T versus 1.5 T but has not been formally investigated in the spine after IV administration of gadolinium-based contrast agent. The purpose of this study is to compare two sequences for gadolinium-enhanced spine imaging at 3 T—fat-saturated T1-weighted FLAIR and fat-saturated T1-weighted fast spin-echo (FSE)—for evaluation of extradural lesions and CSF-cord contrast. MATERIALS AND METHODS. After IV administration of gadolinium-based contrast agent, fat-saturated T1-weighted FSE and FLAIR sequences were obtained in 156 MRI scans of 143 patients at 3 T. Three experienced radiologists compared these sequences for conspicuity differences in bone lesions, disk lesions, other epidural lesions, and cord-CSF contrast. A 7-point visual rating scale was used, with lower numbers indicating increased conspicuity on gadolinium-enhanced fat-saturated T1-weighted FLAIR and higher numbers indicating increased conspicuity on gadolinium-enhanced fat-saturated T1-weighted FSE. RESULTS. A slight increase in the conspicuity of gadolinium-enhancing bone lesions (mean score, 3.6; p < 0.0001), disk lesions (mean score, 3.5; p < 0.0001), and epidural lesions (mean score, 3.4; p < 0.0001) was seen on fat-saturated T1-weighted FLAIR compared with fat-saturated T1-weighted FSE. A higher degree of contrast between the spinal cord and CSF was seen on fat-saturated T1-weighted FLAIR, by a large margin (mean score, 1.8; p < 0.0001). All enhancing lesions seen on fat-saturated T1-weighted FSE images were also seen on fat-saturated T1-weighted FLAIR images. CONCLUSION. Decreased CSF-cord contrast at 3 T, as seen on T1-weighted FSE, can be regained by using T1-weighted FLAIR. Fat-saturated T1-weighted FLAIR may increase conspicuity of gadolinium-enhancing extradural lesions compared with fat-saturated T1-weighted FSE.

To evaluate the effect of half-dose intravenous gadolinium contrast on the enhancement of bone and soft tissue tumors.

The amount of callous needed for fracture stability is typically estimated by a combination of radiographic and physical examinations. Computed tomography (CT) with sagittal and coronal reformations was performed to determine the amount of callous needed for fracture stability based on a quartile analysis of bony bridging of the circumference of the fracture site. All patients who received CT with sagittal and coronal reformations of a fractured tubular bone for the purpose of analyzing bony bridging over a 22-month period were retrospectively reviewed. The final analysis included 34 patients and a total of 47 examinations. Fractures were placed into one of four groups depending on the amount of cortical bridging of the circumference of the bone: group I, 0–24%, group II, 25–49%, group III, 50–74%, group IV, 75–100%. Clinical outcome was determined on the basis of fracture stability, with mean follow-up of approximately 62 weeks. A statistically significant increase in clinical failure was found in patients with 25% bridging, corresponding to a Fisher's exact test p value of 0.045. Patients with less than 25% bridging of the circumference of a tubular bone should be considered high risk for failure, indicating the need for continued protection of the site.

Hematopoietic stem cell transplantation (HSCT) is the only curative therapy for autosomal recessive infantile malignant osteopetrosis, an otherwise fatal disease. HSCT has also been utilized in patients with the less severe autosomal recessive intermediate form in an attempt to correct hematologic abnormalities and halt cranial nerve deficits caused by progressive cranial foraminal stenosis. Successful engraftment is accompanied by rapid normalization of radiographic signs of osteopetrosis.