Faculty Bibliography

Purpose: Examine the accuracy of diagnosing adhesive capsulitis (AC) on MRI, using physical exam and clinical impression of an orthopedic sports clinician as the diagnostic reference standard. Materials and Methods: Retrospective query of our digital database was performed to identify all shoulder MRIs performed at our institution in 2013. The first 100 consecutive subjects aged >40 were included for further review. MRI reports were assessed for the presence of the following information: 1. Thickening of the capsule at the axillary recess (AR), 2. Thickening of the coracohumeral ligament (CHL), 3. Infiltration/ edema of subcoracoid fat, 4. Disproportionate fluid within the proximal biceps tendon sheath, and 5. Imaging impression ofAC. Orthopedic notes were assessed for documented range of shoulder motion and overall clinical impression (10 sports fellowship-trained orthopedic surgeons, 1 shoulder and elbow fellowship-trained orthopedic surgeon, and 1 sports medicine trained primary care physician). Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and overall accuracy were calculated. Fisher exact tests were performed to determine whether each imaging finding was predictive of a positive clinical diagnosis of AC, or likely to predispose to a false positive diagnosis of AC. Results: One hundred shoulder MRI reports in 99 patients were analyzed (59men, 40 women;mean age 58, range 40-87). 17 patients were diagnosed with AC based on imaging findings. Of these patients, frequency of imaging findings included: thickening of the AR (11) or the CHL (8), infiltration of subcoracoid fat (13), and disproportionate fluid in the proximal biceps tendon sheath (3). Six patients had a clinical diagnosis of AC. Fifteen MRIs demonstrated false positive results, while false negative results were seen in 4 cases. The overall sensitivity for theMRI diagnosis of AC was 33.3%with a specificity of 84%. The PPV was 11.8 %,NPV 95.2 %, and overall accuracy 81 %. Fisher exact test P values to determine whether each imaging finding was predictive of a reference standard diagnosis of AC ranged from 0.109 to 1.000. P values to determine whether each imaging finding would lead to a false positive MRI diagnosis were <0.001 for subcoracoid fat infiltration, thickening of the AR, and thickening of the CHL, and p = 1.000 for disproportionate fluid in the biceps tendon sheath. Conclusion: The predictive value of the established MRI findings of adhesive capsulitis may not be as strong as previously shown. Radiologists should be aware of potential imaging over diagnosis and should correlate imaging findings with documented physical exam, when available

Objectives PET/MR may be used in the evaluation of cognitively impaired patients. There are known quantitative differences between PET images obtained on PET/MR scanners when reconstructed with Dixon-MR, CT-based or atlas-based attenuation correction (AC) maps. This study seeks to assess the impact, if any, of these three-different AC methods on the blinded visual interpretation of regional hypometabolism in patients with cognitive impairment. Methods Forty-five minutes following injection of 10 mCi of FDG, 15 patients with cognitive impairment underwent brain PET/CT. PET/MR scanning with a 10 minute PET acquisition and Dixon MR imaging was subsequently performed on a Siemens Biograph mMR scanner under an IRB-approved protocol, at approximately two hours post-injection. A manufacturer-provided non-product offline reconstruction tool was used to reconstruct PET data obtained from PET/MR with AC based on the patient's own CT images, a Dixon-MR derived AC map and an atlas-based AC map that combined Dixon-MR with a segmentation of bony skull structures. Two nuclear medicine physicians blindly scored brain regions (frontal, temporal, parietal, occipital, precuneus) as normal versus hypometabolic using 2D and 3D images generated by MIM software. Abnormal regions were scored as mild, moderate, or severely hypometabolic (score of 0, 1, 2 or 3 respectively). The hypometabolism scores obtained using the different methods of AC were compared and reader agreement assessed. All statistical tests were conducted at the two-sided 5% significance level using SAS 9.3 (SAS Institute, Cary, NC). Results Regional hypometabolism versus normal metabolism was correctly classified (accuracy) for 150 regions in 15 patients by two readers on atlas- and Dixon-based AC map PET reconstructions (versus CT reference AC) for 94% (90 - 96% c.i.) and 93% (89 - 96% c.i.) of all regions. The averaged sensitivity/specificity for detection of any regional hypometabolism was 95%/94% and 90%/91% for atlas-based and Dixon-based AC maps, respectively, compared to the reference standard CT images. The mean absolute error of regional hypometabolism scores for atlas- and Dixon-based PET reconstructions (versus CT) was 0.25 +/- 0.44 and 0.21 +/- 0.42 . There were no statistically significant differences between the visual assessments. Intra-reader agreement for detection of regional hypometabolism was high, with similar outcome assessments when using atlas- and Dixon-corrected PET data in 93% and 93% of scored regions, respectively. The simple kappa coefficient to assess reader agreement in terms of hypometabolism versus normal regions was 0.82 for atlas- and 0.84 for Dixon-based AC. The weighted kappa coefficient to assess reader agreement in terms of the hypometabolism score was 0.75 for atlas- and 0.77 for Dixon-AC. Conclusions Despite the more accurate FDG SUV quantification with CT-based and atlas-based attenuation correction in brain PET/MR compared to Dixon AC, there were no measureable differences between the three AC methods with respect to visual identification of regional hypometabolism in the evaluation of cognitively impaired patients

BACKGROUND AND PURPOSE: Schizophrenia is well-known to be associated with hippocampal structural abnormalities. We used 1H-MR spectroscopy to test the hypothesis that these abnormalities are accompanied by NAA deficits, reflecting neuronal dysfunction, in patients compared with healthy controls. MATERIALS AND METHODS: Nineteen patients with schizophrenia (11 men; mean age, 40.6 +/- 10.1 years; mean disease duration, 19.5 +/- 10.5 years) and 11 matched healthy controls (5 men; mean age, 33.7 +/- 10.1 years) underwent MR imaging and multivoxel point-resolved spectroscopy (TE/TR, 35/1400 ms) 1H-MRS at 3T to obtain their hippocampal GM absolute NAA, Cr, Cho, and mIns concentrations. Unequal variance t tests and ANCOVA were used to compare patients with controls. Bilateral volumes from manually outlined hippocampal masks were compared by using unequal variance t tests. RESULTS: Patients' average hippocampal GM Cr concentrations were 19% higher than that of controls, 8.7 +/- 2.2 versus 7.4 +/- 1.2 mmol/L (P < .05); showing no differences, concentrations in NAA were 8.8 +/- 1.6 versus 8.7 +/- 1.2 mmol/L; in Cho, 2.3 +/- 0.7 versus 2.1 +/- 0.3 mmol/L; and in mIns, 6.1 +/- 1.5 versus 5.2 +/- 0.9 (all P > .1). There was a positive correlation between mIns and Cr in patients (r = 0.57, P = .05) but not in controls. The mean bilateral hippocampal volume was approximately 10% lower in patients: 7.5 +/- 0.9 versus 8.4 +/- 0.7 cm3 (P < .05). CONCLUSIONS: These findings suggest that the hippocampal volume deficit in schizophrenia is not due to net loss of neurons, in agreement with histopathology studies but not with prior 1H-MR spectroscopy reports. Elevated Cr is consistent with hippocampal hypermetabolism, and its correlation with mIns may also suggest an inflammatory process affecting some cases; these findings may suggest treatment targets and markers to monitor them.

Purpose or Case Report: To evaluate the reliability of the UTD classification system Table A. Cross-tabulation of results summarizing inter-reader agreement. There are three distinct reader pairs: score 1 is the score from the arbitrarily designated first reader in each pair and score 2 is from the remaining reader in each pair. Numbers in red denote instances of disagreement. Methods &Materials: This IRB approved, retrospective study included 129 renal ultrasound examinations performed from May 2010 - May 2015 in patients less than 6 months of age for the clinical indication of prenatal hydronephrosis identified by key word search in PACS. Three pediatric radiologists independently reviewed each study for the following: anterior posterior renal pelvic diameter (APRPD), central calyceal dilation (CCD), peripheral calyceal dilation (PPD), renal parenchymal appearance (PA), renal parenchymal thickness (PT), ureteral abnormality, and bladder abnormality. Readers assigned each study a UTD category (normal, UTD P1, UTD P2, UTD P3). Inter-rater percent agreement for individual criteria and overall UTD categorization was assessed. Results: There was overall good inter-reader agreement in assessment of individual criteria (APRPKD, PA, PT, ureter, and bladder) ranging from 85.3 to 96.1% for 3 reader pairs. Inter-reader agreement for CCD and PCD was slightly lower, ranging from 69.0 to 97.7%. Inter-reader agreement for overall risk assesment ranged from 50.4 to 67.4%. Agreement across 3 readers was 48.8% for CCD, 64.3% for PCD, and 37.2% for overall risk stratification. Conclusions: The new UTD classification system is intended to guide clinical management of postnatal urinary tract dilation. For it to be widely accepted and useful, users need to apply it with precision and accuracy. Poor agreement for categorization of risk assessment among our experienced readers suggests that further clarification of the system or training for users is necessary for its optimal use in clinical practice. (Table presented)

PURPOSE: To compare outcomes of imaging pathways in suspected acute appendicitis. METHODS: Computerized tomography (CT) alone, ultrasound alone, and ultrasound followed by CT were compared in 570 emergency department (ED) patients with suspected acute appendicitis. RESULTS: After initial ultrasound, 9.3% of men and 41.0% of women underwent CT. Body mass index (BMI) (P