This study describes anatomic findings of the retrolingual airway in patients that correlate with OSA and can be measured on an upper airway CT. Patients with severe OSA (AHI > or = 40) tend to have retrolingual airways less than 4% of the cross-sectional area of the cervicomandibular ring. The retrolingual airspace is the major site of obstruction in severe OSA and should be carefully evaluated before surgical treatment is considered.

The imaging findings of bisphosphonate-related femoral insufficiency fractures, which include a typical proximal diaphyseal location and transverse liner radiolucency through localized thickening of the lateral cortex, allow a specific diagnosis.

Chemical shift imaging is a useful adjunct MR technique to characterize focal and diffuse marrow abnormalities on routine non-contrast pelvic imaging. It is highly sensitive in identifying malignant disease. Despite its lower specificity, the need for biopsy could be eliminated in more than 60 % of patients with benign disease.

Nephrogenic systemic fibrosis (NSF) may develop in patients with liver disease, a fact highlighted by Food and Drug Administration (FDA) announcements cautioning against the use of gadolinium‐based contrast agents (GBCAs) in select liver disease patients. The purpose of this systematic literature review is to characterize the risk of NSF in patients with liver disease. All published articles on NSF from September 2000 through August 2008, were identified via PubMed searches and examination of articles' reference lists. Two reviewers independently read each article and identified unique patients with biopsy‐proven or suspected NSF. Data on demographics, liver status, renal status, and GBCA exposure were collected. A total of 324 articles were reviewed, with 108 articles containing case descriptions of 335 unique NSF patients. After excluding the 95/335 (28%) patients in whom the presence or absence of liver disease was uncertain, liver disease was confirmed present in 41/239 (17%) patients. Renal insufficiency could be assessed in 35 of the liver disease patients; severe renal insufficiency, defined as a glomerular filtration rate (GFR) or estimated GFR (eGFR) <30 mL/min/1.73 m2 or dialysis requirement, was present in 34/35 (97%) patients. The lone patient who developed NSF with mild/moderate renal insufficiency was atypical and received a total gadodiamide load of 0.76 mmol/kg over a 10‐week period periliver transplantation. The published medical literature demonstrates that patients with liver disease who develop NSF also have severe renal insufficiency, suggesting that liver disease does not confer a risk for NSF beyond that of the underlying renal insufficiency. J. Magn. Reson. Imaging 2009;30:1313–1322. © 2009 Wiley‐Liss, Inc.

Purpose:To show the signal intensity varies with shot number in diffusion-weighted (DW) echo-planar imaging (EPI) and affects apparent diffusion coefficient (ADC) calculation. Materials and Methods:This prospective study was performed on 35 adult patients and 20 volunteers. Measurements were made on a 3T scanner using a breathhold DW spin-echo EPI (SE EPI) sequence. Three protocols were used: A) eight consecutive shots at a fixed b-value of 0 seconds/mm 2 with TR ϭ 1000 and 3000 msec; B) seven consecutive shots at b-values ϭ 0, 1000, 750, 500, 250, 100, 0 seconds/mm 2 (in that order) with TR ϭ 3500 msec; and C) seven consecutive shots (as in B) with TR ϭ 1000, 1750, and 7000 msec.Results: For protocol A, signal intensity decreased significantly from the first to second shot (PϽ0.0001) and thereafter remained constant. For protocol B, the ADC depended on which b ϭ 0 seconds/mm 2 image was used. Using the first b ϭ 0 seconds/mm 2 , the mean ADC was 15% higher than using the second b ϭ 0 seconds/mm 2 (PϽ0.0001). For protocol C, the difference between ADC using the first b ϭ 0 seconds/mm 2 and the second b ϭ 0 seconds/mm 2 decreased as the TR increased. Conclusion:The signal intensity can vary with shot number in SE EPI. For TR Ն 3000 msec, steady-state is attained after one shot. Using data acquired prior to steady-state confounds the calculation of ADC values.

Although it is difficult to discern on anteroposterior radiographs and axial or coronal CT, the fracture is easily identifiable on CT images in the sagittal plane. We advocate reconstruction of CT images of the sacrum in the sagittal plane in trauma to prevent failure of identification.

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