CT characteristics of Morel-Lavallée lesions: an under-recognized but significant finding in acute trauma imaging.

OBJECTIVE: To highlight the significance and imaging characteristics of Morel-Lavallée (ML) lesions, which have been well characterized on MRI, but are potentially under-recognized on CT. MATERIALS AND METHODS: Twenty-eight Morel-Lavallée lesions were identified in 18 patients and were all clinically or surgically confirmed. Lesions were grouped into acute (<3 days), subacute (3-30 days), and chronic (>30 days) at the time of CT imaging. Charts were reviewed to gather patient characteristics, injury patterns, radiologist interpretation, treatment, and outcomes. RESULTS: Sixteen male and 2 female patients with a mean age of 50 years (range 19-80) at the date of their initial evaluation were identified. All patients had significant trauma that accounted for 28 ML lesions, all of which were in a characteristic subcutaneous location overlying the muscular fascial plane. Lesions on CT went through an evolution from hyperdense, poorly or moderately marginated without a pseudocapsule to being hypodense, with internal fat globules or septations and well marginated with a complete enhancing pseudocapsule. Only 1 (4 %) of the ML lesions was suggested and 7 (25 %) lesions were not commented on at all by the interpreting radiologist. CONCLUSION: Morel-Lavallée lesions are post-traumatic closed, internal, soft-tissue, degloving lesions that are potentially underrecognized on CT. Most acute ML lesions are nonspecific, resembling simple hematomas or contusions. ML lesions evolve as they age with subacute and chronic lesions demonstrating the known features described on MR imaging that should allow for an accurate imaging diagnosis.

Imaging findings in 22 cases of Schnitzler syndrome: characteristic para-articular osteosclerosis, and the "hot knees" sign differential diagnosis.

BACKGROUND AND PURPOSE: Schnitzler syndrome is characterized by chronic urticaria, monoclonal gammopathy, and a risk of developing lymphoproliferative disorders. Patients frequently present with bone pain, fever, arthralgia, and lymphadenopathy. The purpose of this study is to retrospectively review and evaluate potentially attributable imaging abnormalities in a series of patients with clinically diagnosed Schnitzler syndrome. MATERIALS AND METHODS: Clinical and pathological chart review identified 22 patients meeting Strasbourg criteria for Schnitzler syndrome. Imaging of these patients was retrospectively reviewed by a musculoskeletal radiologist and a radiology fellow to determine and characterize significant "positive" findings that could potentially be attributed to their primary disease process. RESULTS: Evidence of abnormal bone remodeling was present in 64% (14/22) of patients with 40 bone abnormalities. Lesions were predominantly or entirely sclerotic and most commonly involved the distal femora (n = 11), proximal tibiae (nine), and innominate bones (six). Patterns of involvement were variable, but typically eccentrically intramedullary, cortical, and juxta-articular. Skeletal surveys and targeted radiographs identified only 37% (10/27) of abnormal bones subsequently "positive" by additional modalities. PET and bone scans were all positive in patients with bone sclerosis (13/13 and 17/17 bone sites, respectively). CONCLUSIONS: Schnitzler syndrome often presents with characteristic osteosclerosis, most commonly around the knees and in the pelvis. In patients with a suggestive clinical history, the radiologist could direct an appropriate imaging strategy or might to be the first to suggest the diagnosis. Bone scan may be the most appropriate initial screening tool in suspected cases.

Osseous sarcoidosis: a case of evolving MR appearances correlating with clinical symptoms.

Osseous sarcoidosis of the axial skeleton is typically asymptomatic and not routinely imaged with MRI. The natural history of sarcoidosis is generally felt to be resolution spontaneously or with treatment, or unremitting progression. We report a case of recurrent active symptomatic disease after an initial response to immunomodulator treatment with an unusual halo of T2-hyperintensity surrounding treated fibrofatty vestigial lesions.

Pick up a book or "google it?" a survey of radiologist and trainee-preferred references and resources.

The purpose of this study was to investigate radiologist and trainee-preferred sources for solving imaging questions. The institutional review board determined this study to be exempt from informed consent requirements. Web-based surveys were distributed to radiology staff and trainees at 16 academic institutions. Surveys queried ownership and use of tablet computers and habits of utilization of various electronic and hardcopy resources for general reference. For investigating specific cases, respondents identified a single primary resource. Comparisons were performed using Fisher's exact test. For staff, use of Google and online journals was nearly universal for general imaging questions (93 [103/111] and 94 % [104/111], respectively). For trainees, Google and resident-generated study materials were commonly utilized for such questions (82 [111/135] and 74 % [100/135], respectively). For specific imaging questions, online journals and PubMed were rarely chosen as a primary resource; the most common primary resources were STATdx for trainees and Google for staff (44 [55/126] and 52 % [51/99], respectively). Use of hard copy journals was nearly absent among trainees. Sixty percent of trainees (78/130) own a tablet computer versus 41 % of staff (46/111; p = 0.005), and 71 % (55/78) of those trainees reported at least weekly use of radiology-specific tablet applications, compared to 48 % (22/46) of staff (p < 0.001). Staff radiologists rely heavily on Google for both general and specific imaging queries, while residents utilize customized, radiology-focused products and apps. Interestingly, residents note continued use of hard copy books but have replaced hard copy journals with online resources.

Neuromuscular choristoma: characteristic magnetic resonance imaging findings and association with post-biopsy fibromatosis.

OBJECTIVE: To describe imaging characteristics of neuromuscular choristomas (NMC) and to differentiate them from fibrolipomatous hamartomas (FLH). MATERIALS AND METHODS: Clinical and imaging characteristics of six patients with biopsy-proven NMC and six patients with FLH were reviewed by musculoskeletal, a pediatric, and two in-training radiologists with a literature review to define typical magnetic resonance imaging features by consensus. Five radiology trainees blinded to cases and naive to the diagnosis of NMC and a musculoskeletal-trained radiologist rated each lesion as having more than or less than 50% intralesional fat, as well as an overall impression using axial T1 images. Sensitivity, specificity, accuracy, and interobserver agreement kappa were determined. RESULTS: Typical features of NMC include smoothly tapering, fusiform enlargement of the sciatic nerve or brachial plexus elements with T1 and T2 signal characteristics closely following those of muscle. Longitudinal bands of intervening low T1 and T2 signal were often present and likely corresponded to fibrous tissue by pathology. Four of five patients with long-term follow-up (80%) developed aggressive fibromatosis after percutaneous or surgical biopsy. Nerve fascicle thickening often resulted in a "coaxial cable" appearance similar to classic FLH, however, using a cutoff of <50% intralesional fat allowed for differentiation with 100% sensitivity by all reviewers and 100% specificity when all imaging features were utilized for impressions. Agreement was excellent with all differentiating methods (kappa 0.861-1.0). CONCLUSIONS: NMC can be confidently differentiated from FLH and malignancies using characteristic imaging and clinical features. When a diagnosis is made, biopsy should be avoided given frequent complication by aggressive fibromatosis.

Progressive nerve territory overgrowth after subtotal resection of lipomatosis of the median nerve in the palm and wrist: a case, a review and a paradigm.

BACKGROUND: Lipomatosis of the nerve (LN) is a rare disorder characterized by the massive enlargement of peripheral nerves, frequently accompanied by generalized fibroadipose proliferation and skeletal overgrowth. The treatment of this disorder remains controversial, in part because of the rarity and the variability of presentation. Some authors have advocated total resection of this benign lesion including the functioning nerve, while others recommend symptomatic decompression alone. METHODS: We have been routinely following a 10-year-old boy for lipomatosis of the median nerve at the wrist noted shortly after birth. He underwent median nerve resection accompanied by sural nerve grafting at another institute. We review the literature on LN and the efficacy of nerve grafting. RESULTS: Clinically, he made a good recovery, with mild loss of thenar function and relatively preserved sensation. Serial magnetic resonance imaging over 5 years has revealed progression of the LN at both coaptation sites, fibrofatty proliferation within the nerve grafts as well as distal digital nerves, and enlargement of a fibrous scar at the coaptation sites. This has never been reported in the 9 decades of study of this disease. CONCLUSION: We present the first medium-term follow-up of a patient who underwent nerve sacrifice to attempt to cure the LN alongside a historical review of treatment. We believe that macroscopic gross total resection (i.e., microscopic subtotal resection) is insufficient in stopping the potential progression of this hamartomatous lesion because of the persistent effect of trophic factors.

An assessment of incentive versus survey length trade-offs in a Web survey of radiologists.

BACKGROUND: It is generally understood that shorter Web surveys and use of incentives result in higher response rates in Web surveys directed to health care providers. Less is known about potential respondent preference for reduced burden as compared to increased reward. OBJECTIVE: To help elicit preference for minimized burden compared to reward for completion of a survey, we observed physician preferences for shorter Web surveys compared to incentives as well as incentive preference (small guaranteed incentive compared to larger lottery incentive) accompanying an electronic request to complete a survey. METHODS: This was an observational study that accompanied a large Web survey study of radiology staff, fellows, and residents at select academic medical centers in the United States. With the request to complete the survey, potential respondents were offered three options: (1) a 10-minute Web survey with the chance to win an iPad, (2) a 10-minute Web survey with a guaranteed nominal incentive ($5 amazon.com gift card), or (3) a shorter (5-7 minute) Web survey with no incentive. A total of 254 individuals responded to the Web survey request. RESULTS: Overwhelmingly, individuals chose a longer survey accompanied by an incentive compared to a shorter survey with no incentive (85% compared to 15%, P<.001). Of those opting for an incentive, a small, but not significant majority chose the chance to win an iPad over a guaranteed $5 gift card (56% compared to 44%). CONCLUSIONS: When given the choice, radiologists preferred a reward (either guaranteed or based on a lottery) to a less burdensome survey, indicating that researchers should focus more attention at increasing perceived benefits of completing a Web survey compared to decreasing perceived burden.

Gas-containing gallstones as a cause of the "effervescent gallbladder" sign and pneumobilia.

The "effervescent gallbladder" sign, the sonographic finding of tiny echogenic foci rising from the dependent portion of the gallbladder, reminiscent of bubbles rising in a glass of champagne, has been reported previously as a finding of emphysematous cholecystitis. We report two additional cases of this unusual finding in an asymptomatic patient and in a patient with acute, gangrenous cholecystitis, confirmed in both cases by CT, to be secondary to the release of gas from gallstones. These two cases cast doubt on the sonographic sign as a pathognomonic finding of emphysematous cholecystitis.

Long-term progression of lipomatosis of nerve.

OBJECTIVE: Lipomatosis of nerve (LN) is a condition of massive peripheral nerve enlargement due to proliferation of fibrous and adipose tissue within the nerve, the natural history of which is currently unknown. We measured the pattern of growth in individuals with long-term radiologic follow-up. METHODS: Review of the searchable records for LN at our institution found 52 patients, confirmed by pathology or pathognomic appearance on MRI. Ten patients had serial MRI of the same anatomic region for more than 2 years of clinical follow-up. Volumetric analysis was performed using regions of interest on serially imaged segments of affected nerves. Adjustment for skeletal growth was performed for pediatric patients. RESULTS: LN enlarged in 7 of 10 individuals, often both longitudinally along the nerve and in cross-sectional volume. Regarding cross-sectional volume, 2 of the 10 patients demonstrated volume growth more than doubling and 5 additional patients had a >20% increase in nerve volume; the remaining 3 patients were quiescent, where change in the nerve volume was within the error range of volumetric analysis. All cases with growth remained >20% after adjustment for skeletal growth. Five of 10 individuals had longitudinal extension, even with correction for skeletal growth. More significant growth was noted in younger patients (P=0.02). Growth rates more than 5% per year correlated with surgery, without statistical significance in this small population (P=0.14). CONCLUSIONS: Serial MRI reveals progressive enlargement of LN. The rate of growth was more profound in youth, but also occurred in early adulthood.

Utility of gadolinium-enhanced MR urography in detection of bladder carcinoma.

OBJECTIVES: To evaluate the diagnostic accuracy of MR urography (MRU) in detecting bladder carcinoma. METHODS: A retrospective review of 107 MRU exams obtained to evaluate for possible upper urinary tract urothelial carcinoma from 5/2005 to 5/2009 was performed by two experienced abdominal radiologists. Interpretation of the presence or absence of bladder carcinoma and lesion conspicuity in each imaging phase was made using 5-point confidence grading scales. Exams included 3D T1-weighted spoiled gradient-recalled echo images through the kidneys, ureters and bladder in the coronal plane during parenchymal phases and in both coronal and axial planes during pyelographic phases after intravenous administration of gadolinium and furosemide. Standard of reference was cystoscopy or cystectomy within 30 days of MRU. Statistical measures of performance, including receiver operating characteristics area under the curve (Az) values were calculated. RESULTS: Bladder carcinoma was present in 26/107 patients (24%). Sensitivity, specificity, accuracy, positive predictive value, negative predictive value and Az value were 73.1%, 91.4%, 86.9%, 73.1%, 91.4%, 0.89 for the first reviewer, and 84.6%, 75.3%, 77.6%, 52.4%, 93.8%, 0.86 for the second. Lesion conspicuity was superior on the parenchymal phase compared to the pyelographic phase (p=0.04). CONCLUSIONS: MRU obtained for suspicion of upper urinary tract TCC has a moderate accuracy in detecting bladder carcinoma.

A functional near-infrared spectroscopy study to detect activation of somatosensory cortex by peripheral nerve stimulation.

INTRODUCTION: Multi-channel near-infrared spectroscopy (NIRS) is a method for non-invasively monitoring of relative concentrations of oxygenated, deoxygenated, and total hemoglobin. This technique has found expanding application in brain mapping and functional imaging. The purpose of this study was to investigate whether activation of somatosensory cortex can be detected without the necessity of the patient's cooperation in performing a task. METHODS: Real-time bilateral parietotemporal cerebral oxygenation was monitored in 12 healthy volunteers. The median nerve at the wrist was electrically stimulated repeatedly at an amplitude below the threshold of discomfort. Interstimulus intervals were randomized between 13 and 31 s to minimize synchronization with respiration or other natural oscillations in cerebral oxygenation. RESULTS: In 8 of the 12 subjects, activation over the contralateral primary somatosensory cortex was detected, correlating significantly with the predicted hemodynamic response function. CONCLUSIONS: To our knowledge, this is the first time functional NIRS has been used to detect activation of somatosensory cortex with peripheral nerve stimulation. While the sensitivity for detection of the functional hemodynamic response was inadequate for clinical diagnostics, these findings are uniquely important in critical care imaging in that the regional blood flow and oxygenation changes can be detected without the requirement of a volitional task. This advancement potentially expands the capability of this modality to be used in brain mapping and in the evaluation of patients with impaired cognitive or motor function at the bedside.

High-resolution 7T MRI of the human hippocampus in vivo.

PURPOSE: To describe an initial experience imaging the human hippocampus in vivo using a 7T magnetic resonance (MR) scanner and a protocol developed for very high field neuroimaging. MATERIALS AND METHODS: Six normal subjects were scanned on a 7T whole body MR scanner equipped with a 16-channel head coil. Sequences included a full field of view T1-weighted 3D turbo field echo (T1W 3D TFE: time of acquisition (TA)=08:58), T2*-weighted 2D fast field echo (T2*W 2D FFE: TA=05:20), and susceptibility-weighted imaging (SWI: TA=04:20). SWI data were postprocessed using a minimum intensity projection (minIP) algorithm. Total imaging time was 23 minutes. RESULTS: T1W 3D TFE images with 700 microm isotropic voxels provided excellent anatomic depiction of macroscopic hippocampal structures. T2*W 2D FFE images with 0.5 mm in-plane resolution and 2.5 mm slice thickness provided clear discrimination of the Cornu Ammonis and the compilation of adjacent sublayers of the hippocampus. SWI images (0.5 mm in-plane resolution, 1.0 mm slice thickness) delineated microvenous anatomy of the hippocampus. CONCLUSION: In vivo 7T MR imaging can take advantage of higher signal-to-noise and novel contrast mechanisms to provide increased conspicuity of hippocampal anatomy.