Hepatic Heterogeneity and Attenuation on Contrast-Enhanced CT in Patients With the Hypovolemic Shock Complex: Objective Classification Using a Contemporary Cohort.

OBJECTIVE: When objectively measured on computed tomography (CT), does hepatic heterogeneity or overall liver attenuation predict the presence of shock? METHODS: This retrospective study included 73 patients (mean age 33 years) with the hypoperfusion shock complex (HSC) on CT (cases) and 100 patients (mean age 43 years) with negative trauma CT scans (controls). Liver heterogeneity was calculated by using consistently sized regions of interest (ROIs) to measure the 2 highest and the 2 lowest areas of hepatic density (in Hounsfield units [HU]). The difference between the means of the 2 highest and 2 lowest ROIs was considered the heterogeneity. Attenuation was calculated using the mean of 3 randomly placed ROIs. Both heterogeneity and attenuation were then compared between cases and controls. RESULTS: Median hepatic heterogeneity was 16.8 HU (IQR: 10.7-23.4) for the HSC group and 9.0 HU (IQR: 7.0-10.4) for the controls (P < 0.001). The area under the curve was 0.79, and a threshold of 30 HU yielded a specificity of 100%. Median hepatic attenuation was not significantly different between the HSC and the control groups, with an area under the curve of 0.56. CONCLUSIONS: Increased hepatic heterogeneity may represent an objective marker of the HSC that performs in a similar manner to other established signs. By comparison, overall hepatic hypoattenuation is a poor indicator of the HSC.

Solitary, Well-Circumscribed, T2 Hyperintense Masses on MRI Have Very Low Malignancy Rates.

OBJECTIVE: The purpose of this study was to determine the malignancy rate of solitary MRI masses with benign BI-RADS descriptors. METHODS: A retrospective review was conducted of all breast MRI reports that described a mass with a final BI-RADS assessment of 3, 4, or 5, from February 1, 2005, through February 28, 2014 (n = 1510). Studies were excluded if the mass was not solitary, did not meet formal criteria for a mass, or had classically suspicious BI-RADS features (e.g., washout kinetics, and spiculated margin). The masses were reviewed by 2 fellowship-trained breast radiologists who reported consensus BI-RADS mass margin, shape, internal-enhancement, and kinetics descriptors. The T2 signal was reported as hyperintense if equal to or greater than the signal intensity of the axillary lymph nodes. Pathology results or 2 years of imaging follow-up were recorded. Comparisons were made between mass descriptors and clinical outcomes. RESULTS: There were 127 women with 127 masses available for analysis. There were 76 (60%) masses that underwent biopsy for an overall malignancy rate of 4% (5/127): 2 ductal carcinoma in situ (DCIS) and 3 invasive ductal carcinoma. The malignancy rate was 2% (1/59) for T2 hyperintense solitary masses. The malignancy rate was greater than 2% for all of the following BI-RADS descriptors: oval (3%, 3/88), round (5%, 2/39), circumscribed (4%, 5/127), homogeneous (4%, 3/74), and dark internal septations (4%, 2/44). CONCLUSION: T2 hyperintense solitary masses without associated suspicious features have a low malignancy rate, and they could be considered for a BI-RADS 3 final assessment.

Splenic contraction: a new member of the hypovolemic shock complex.

OBJECTIVE: The objective of the article is to assess changes in splenic volume in the setting of hypovolemic shock; splenic enhancement in hypovolemic shock is also assessed. MATERIALS/METHODS: 71 consecutive adult patients with the hypovolemic shock complex on computed tomography (CT) were identified. Spleen volume and enhancement were compared to a baseline CT scan (without shock) or to height- and sex-corrected normal values and a control population when a comparison CT was unavailable. RESULTS: Splenic volume was significantly lower in the setting of shock. Average splenic volume in adult patients with shock was 107 ± 63 cm3 compared to 220 ± 164 cm3 in the control population (P < 0.001). All shock patients with a comparison CT (n = 35) had decreased splenic volume in the setting of shock. The area under the receiver operating characteristic (ROC) curve for spleen volume predicting shock was 0.83. Splenic enhancement was also significantly lower in the setting of shock. Mean splenic attenuation value in our shock population was 105 ± 34 HU compared to 134 ± 25 HU in the control population (P < 0.001). Decreased splenic enhancement was present in 25 of 71 shock patients and in none of the control patients (P < 0.001). CONCLUSION: Decreased splenic volume is a ubiquitous and reliable sign of hypovolemic shock and should be considered a member of the hypovolemic shock complex. It is of particular utility when a prior study is available. Splenic hypoenhancement has high specificity and a high positive predictive value for hypovolemic shock in the correct patient population.

CT assessment of the prevalence of retinacular injuries associated with hindfoot fractures.

OBJECTIVE: To determine the incidence of injuries to the flexor and peroneal retinacula in hindfoot fractures as demonstrated on ankle computed tomography (CT). MATERIALS AND METHODS: Study patients were identified via review of CT records at a single institution. CT scans were retrospectively reviewed and compared with surgical reports. RESULTS: Hindfoot fractures undergoing CT showed flexor retinacular injuries in 23.7% of cases and peroneal retinacular injuries in 10.2%. The posterior tibial tendon was partly torn in 4.2% of cases, and entrapped between fracture fragments in 16.1%. The peroneal tendon was rarely injured, being entrapped in 1.7% of cases. Pilon, distal tibial shaft, malleolar, talar, and calcaneal fractures were all associated with retinacular injuries. CT findings correlated well with surgical findings; there were no false-positive CT findings, and only 1 false-negative finding, a posterior tibial tendon that was entrapped at surgery, but in a normal position on the CT. CONCLUSIONS: Retinacular injuries are commonly demonstrated on CT in patients with ankle fractures. The contribution of these injuries to fracture outcomes is unknown.

Emergency Medicine resident anesthesia training in a private vs. academic setting.

BACKGROUND: Airway management is an essential part of any Emergency Medicine (EM) training program. Academic centers typically provide training to many learners at various training levels in a number of medical specialties during anesthesiology rotations. This potentially creates competition for intubation procedures that may negatively impact individual experiences. OBJECTIVES: We hypothesized that residents would report higher numbers of intubations and improved educational value in a private practice, rather than an academic, anesthesiology rotation. METHODS: EM residents' anesthesiology training was evaluated pre and post a change in training setting from an academic institution to a private practice institution. Outcome measures included the number of self-reported intubations, resident ratings of the rotation, and the number of positive comments. Residents' evaluation was measured with: a 14-item evaluation; subjective comments, which two blinded reviewers rated as positive, negative, or neutral; and transcripts from structured interviews to identify themes related to training settings. RESULTS: The number of intubations increased significantly in the private practice setting (4.6 intubations/day vs. 1.5 intubations/day, p < 0.001). Resident evaluations improved significantly with the private practice experience (mean scores of 3.83 vs. 2.23, p-values <0.05). Residents' impressions were also significantly higher for the private practice setting with respect to increased educational value, greater use of adjunct airway devices, and directed teaching. CONCLUSIONS: Number of intubations performed and residents' rating of the educational value were more favorable for a private practice anesthesiology rotation. Alternative settings may provide benefit for training in areas that have competition among trainees.

Comparison of 18F-fluorodeoxyglucose and 18F-fluorothymidine PET in differentiating radiation necrosis from recurrent glioma.

PURPOSE: The objective was to compare F-fluorodeoxyglucose (FDG) and F-fluorothymidine (FLT) PET in differentiating radiation necrosis from recurrent glioma. MATERIALS AND METHODS: Visual and quantitative analyses were derived from static FDG PET and static and dynamic FLT PET in 15 patients with suspected recurrence of treated grade 2 glioma or worse with a new focus of Gd contrast enhancement on MRI. For FDG PET, SUVmax and the ratio of lesion SUVmax to the SUVmean of contralateral white matter were measured. For FLT PET, SUVmax and Patlak-derived metabolic flux parameter Kimax were measured for the same locus. A 5-point visual confidence scale was applied to FDG PET and FLT PET. Receiver operating curve analysis was applied to visual and quantitative results. Differences between recurrent tumor and radiation necrosis were tested by Kruskal-Wallis analysis. On the basis of follow-up Gd-enhanced MRI, lesion-specific recurrent tumor was defined as a definitive increase in size of the lesion, and radiation necrosis was defined as stability or regression. RESULTS: For FDG SUVmax, the FDG ratio of lesion-white matter, and FLT Kimax, there was a significant difference between mean values for recurrent tumor and radiation necrosis. Recurrent tumor was best identified by the FDG ratio of lesion-contralateral normal white matter (area under the curve of 0.98, confidence interval of 0.91 to 1.00, sensitivity of 100%, and specificity of 75% for an optimized cutoff value of 1.82). CONCLUSIONS: Both quantitative and visual determinations allow accurate differentiation between recurrent glioma and radiation necrosis by both FDG and FLT PET. In this small series, FLT PET offers no advantage over FDG PET.