Role of diffusion tensor imaging of sciatic nerve in symptomatic patients with inconclusive lumbar MRI.

OBJECTIVE: To assess fractional anisotropy (FA) of sciatic nerve roots within the pelvis by using diffusion tensor imaging (DTI) in patients suffering from sciatica with inconclusive lumbar MRI. METHODS: This IRB-approved prospective study included 32 consecutive subjects (11 males and 21 females; mean age 32.2 years) between September 2019 and February 2020. All patients underwent DTI (TR/TE 5800/97 ms; b = 1000; slice thickness 3,5 mm; directions = 20) on a 1.5 T scanner (Siemens Aera). Seventeen patients were symptomatic, whereas 15 patients served as control group. DTI data were analyzed by two radiologists (25 and 11 years of experience, respectively) blinded to clinical data. Each radiologist placed two ROIs on the nerve roots at three different levels. Diagnostic accuracy values of FA numbers were calculated by using receiver operator curves (ROC) and relative area under the curve (AUC), by using clinical findings as standard of reference. Inter-observer agreement was calculated with k-statistics. Paired T-test and Mann-Whitney test were used for comparison accordingly to data distribution. A value of p < 0.05 was considered statistically significant. RESULTS: Among the 17 symptomatic patients, FA values were significantly lower in the affected side at all levels (p < 0.05). The FA ratio (FA affected side/FA unaffected side) of symptomatic patients was significantly lower compared to control group at level 1 (p = 0.0005) and level 2 (p = 0.0006). Using a threshold of 0.90 for level 1 and 0.73 for level 2, 76 % and 71 % sensitivity and 100 % and 87 % specificity were achieved, respectively. CONCLUSION: DTI can quantitatively demonstrate sciatic nerve roots impairment within the pelvis.

Evaluation of glenoid labral tears: comparison between dual-energy CT arthrography and MR arthrography of the shoulder.

OBJECTIVE: To compare the diagnostic accuracy of dual-energy computed tomography arthrography (DE-CTA) and magnetic resonance arthrography (MRA) of the shoulder in depicting glenoid labral tears. METHODS: This prospective institutional review board-approved study included 47 consecutive patients (28 males, 19 females; mean age of 34.2 years) studied between January 2017 and October 2018. All patients underwent DE-CTA and MRA the same day. Two radiologists (25 and 11 years of experience, respectively), blinded to clinical data, evaluated the presence labral tears on virtual-blended 120 kV standard CTA and on DE-CTA images. A third radiologist (18 years of experience) evaluated the MRA images. Diagnostic accuracy values were calculated by using surgery as standard of reference. Inter-observer and intra-observer agreements were calculated with k statistics. A value of p < 0.05 was considered statistically significant. RESULTS: Surgery revealed the presence of labral tears in 38/47 patients (80.9%). Sensitivity and specificity values in diagnosing labral tears were 84.2% and 77.8% for MRA (Reader 3), 84.2% and 77.8% for CTA (Reader 1), 84.2% and 88.9% for CTA (Reader 2), 89.5% and 88.9% for DE-CTA (Reader 1), and 92.1% and 88.9% for DE-CTA (Reader 2). A nonsignificant increase in AUC values with respect to MRA was obtained by reading the CTA (p = 0.470) and DE-CTA dataset (p = 0.217), respectively. Inter-observer agreements were near perfect for CTA (k = 0.84) and substantial for DE-CTA reading (k = 0.76). Intra-observer agreements were near perfect both for CTA (k = 0.88) and for DE-CTA reading (k = 0.82). CONCLUSION: DE-CTA and MRA were not different in terms of diagnostic performance.

Identification of bone marrow edema of the ankle: diagnostic accuracy of dual-energy CT in comparison with MRI.

OBJECTIVE: To evaluate the diagnostic accuracy of dual-energy computed tomography (DECT) to identify bone marrow edema (BME) of the ankle. METHODS: This prospective institutional review board approved study included 40 consecutive patients (29 males and 11 females; mean age of 32.3 years) studied with DECT (80 kV and tin filter 150 kV) and MRI within 10 days. DECT data were post-processed for generating non-calcium images of the ankle. Two radiologists evaluated the presence of BME on color-coded maps. Diagnostic accuracy values for diagnosing BME were calculated for DECT maps (qualitative assessment) and for CT numbers (quantitative assessment) by using receiver operator curves and area under the curve (AUC), using MRI as the gold standard. Interobserver and intraobserver agreements were calculated with k-statistics. A p < 0.05 was considered statistically significant. RESULTS: DECT depicted BME in 23/25 patients (92.0%). The sensitivity, specificity, PPV and NPV, and accuracy achieved by evaluating the DECT images were 92.0, 86.6, 92.0, 84.6, and 90.0%, for reader 1 and 88.0, 86.6, 91.6, 78.6, and 87.5, for reader 2, respectively. The interobserver and intraobsever agreements were near perfect (k = 0.87 and k = 0.83, respectively). DECT numbers were significantly different between positive (mean - 12.6 ± 29.6 HU) and negative cases (mean - 64.2 ± 34.5 HU) with a p value < 0.001. By using - 20HU cutoff to identify BME (AUC of 0.896.), the sensitivity, specificity, PPV and NPV, and accuracy of the quantitative analysis were 88.0, 92.6, 95.7, 92.6, and 87.5%, respectively. CONCLUSION: DECT represents an accurate imaging tool for demonstration of BME of the ankle when compared to MRI.

Solid Pseudopapillary Neoplasms of the Pancreas: Clinicopathologic and Radiologic Features According to Size.

OBJECTIVE. The purpose of this study was to retrospectively analyze and correlate clinicopathologic and radiologic features of resected solid pseudopapillary neoplasms of the pancreas according to their size. MATERIALS AND METHODS. Clinicopathologic and radiologic features of 106 resected solid pseudopapillary neoplasms of the pancreas over a 20-year period were retrospectively analyzed. Tumors were divided into three groups according to their size (≤ 30 mm, 31-50 mm, and ≥ 51 mm). Clinicopathologic and radiologic features were compared among groups using Kruskal-Wallis and Fisher exact tests. RESULTS. Forty-one tumors that were 30 mm or smaller, 30 tumors between 31 and 50 mm, and 35 tumors that were 51 mm or larger were included. Preoperative MRI of 76 patients and CT of 40 patients were examined. Patients with tumors that were 30 mm or smaller were significantly older than the other groups of patients (p = 0.038). Large tumors (31-50 and ≥ 51 mm) were more frequently located in the pancreatic body or tail (p = 0.008). Most tumors had well-defined margins (87.7%) and a mixed solid and cystic appearance (54.7%) at imaging; tumors that were 30 mm or smaller were more frequently entirely solid (p = 0.028). At histologic analysis, 13 tumors had at least one feature of malignancy; nodal and liver metastases were found in one patient (0.9%). No significant differences between groups were found regarding the presence of malignant histologic features (p = 0.932). The rate of incorrect preoperative diagnosis was higher in tumors 30 mm or smaller, albeit without significant differences between groups (p = 0.561). CONCLUSION. Malignancy in solid pseudopapillary neoplasms is not correlated with tumor size; tumors that are 30 mm or smaller may present atypical imaging features, which may overlap those of other solid tumors of the pancreas.

Added value of MRI tractography of peri-prostatic nerve plexus to conventional T2-WI in detection of extra-capsular extension of prostatic cancer.

PURPOSE: To evaluate the role of DTI (with fibretracking) and T2-weighted imaging (T2-WI) used together for predicting extra-capsular extension in patients with localized prostate cancer. METHOD AND MATERIALS: Thirty-six patients with biopsy-proven diagnosis of prostatic neoplasia performed MRI and underwent radical prostatectomy. Histopathological analysis showed ECE in 15/36 and capsule sparing in 21/36. By means of T2-WI, ECE was evaluated in a qualitative manner, according to PI-RADS v.2 (two groups with low and high risk of ECE); sensitivity and specificity were calculated for both groups. We performed a quantitative analysis on two tractographic parameters, fractional anisotropy (FA) and apparent diffusion coefficient (ADC) and computed the ratio between the lesion quadrant and its contralateral (L/H ratio). We compared L/H ratios of patients with and without ECE; ROC analyses were performed to determinate ECE cut-off values of tractographic parameters. These cut-off values were used in association with T2-WI to reassess patients and to evaluate whether specificity and sensitivity of ECE detection change. RESULTS: T2-WI showed a sensitivity of 80% and a specificity of 71% in detection of ECE. Tractography displayed a significant difference in L/H ratio for FA and ADC between patients with and without ECE. The simultaneous use of T2-WI and tractography revealed high sensitivity (100%) on patients with low suspect of ECE (on T2-WI) and high specificity (83%) on patients with high suspect of ECE (on T2-WI). CONCLUSION: The morphologic component of T2-weighted imaging and functional aspect of DTI should be interpreted together to more successfully assess the presence of ECE.

Identification of residual-recurrent cholesteatoma in operated ears: diagnostic accuracy of dual-energy CT and MRI.

PURPOSE: The aim of this study was to compare the diagnostic accuracy of magnetic resonance imaging (MRI) and dual-energy computed tomography (DECT) to identify residual-recurrent cholesteatoma using the second-look surgery as the reference standard. METHODS: This prospective, institutional review board-approved study included 19 consecutive patients (11 males and 8 females; mean age of 62.2, range 34-80 years). Since five patients were studied bilaterally, a total of 24 ears were evaluated with DECT and MRI between February 2017 and June 2018. Any abnormal middle ear attenuation on high-resolution CT images (HRCT) or DECT color-coded maps, and any abnormal signal on MRI images was evaluated by four experienced radiologists. Diagnostic accuracy values of HRCT, DECT maps and CT numbers (by using receiver operator curves) and MRI were compared. Interobserver and intraobserver agreement were calculated. RESULTS: Residual-recurrent cholesteatoma was diagnosed at surgery in 16/24 ears (66.6%). MRI and DECT revealed a total of 15/16 and 14/16 cholesteatomas, respectively. The sensitivity, specificity, PPV and NPV and accuracy of MRI and DECT were 93.7, 87.5, 93.7, 87.5, and 91.6% and 87.5, 87.5, 93.3, 87.5 and 87.5%, respectively. CT numbers were significantly different between positive (mean 57.6 HU, range - 65, 112 HU) and negative cases (mean 5.4 HU, range - 100, 66 HU) with p < 0.001. The interobserver and intraobserver agreement were k = 0.87 and k = 0.83, respectively. CONCLUSION: DECT may provide an accurate demonstration of residual-recurrent middle ear cholesteatoma.

Diagnostic accuracy of dual-energy CT and virtual non-calcium techniques to evaluate bone marrow edema in vertebral compression fractures.

PURPOSE: The aim of this study was to evaluate DECT diagnostic accuracy in the identification of vertebral bone marrow edema, using MRI as standard of reference. METHODS: This prospective institutional review board-approved study included 76 consecutive patients (29 males and 47 females; mean age 62.3, range 51-82 years) studied with DECT (90 kV and tin filter 150 kV) and MRI within 7 days. Three radiologists evaluated DECT (reader 1 and 2) and MRI images (reader 3). Diagnostic accuracy of the DECT maps (qualitative assessment) and of the CT numbers (quantitative assessment), interobserver and intraobserver agreements were calculated. RESULTS: MRI revealed 61 edematous vertebrae and 52 collapsed non-edematous vertebrae. The sensitivity, specificity, PPV and NPV and accuracy of the qualitative assessment of the DECT maps were 88.6, 92.3, 93.1, 87.3 and 90.3%, for reader 1, 90.2, 90.3, 91.6, 88.7 and 90.3, for reader 2, and 91.8, 90.4, 91.6, 90.4 and 91.1% for quantitative analysis, respectively. DECT numbers were significantly different between positive (mean - 23 HU, range - 189, 29 HU) and negative cases (mean - 126 HU, range - 321, - 66 HU) with p < 0.001. The ROC curve analysis revealed an AUC of 0.886 (95% confidence interval 0.722-0.913). The interobserver and intraobserver agreements were near perfect (k = 0.87 and k = 0.83, respectively). CONCLUSION: DECT represents an accurate imaging technique for demonstrating bone marrow edema in vertebral compression fracture, if compared to MRI.

Association Between Changes in Body Composition and Neoadjuvant Treatment for Pancreatic Cancer.

Importance: Sarcopenia and sarcopenic obesity have been associated with poor outcomes in unresectable pancreatic cancer (PC). Neoadjuvant treatment (NT) is used increasingly to improve resectability; however, its effects on fat and muscle body composition have not been characterized. Objectives: To evaluate whether NT affects muscle mass and adipose tissue in patients with borderline resectable PC (BRPC) and locally advanced PC (LAPC) and determine whether there were potential differences between patients who ultimately underwent resection and those who did not. Design, Setting, and Participants: In this retrospective cohort study conducted at 4 academic medical centers, 193 patients with BRPC and LAPC undergoing surgical exploration after NT who had available computed tomographic scans (both at diagnosis and preoperatively) and confirmed pancreatic ductal adenocarcinoma were evaluated. The study was conducted from January 2013 to December 2015. Data analysis was performed from September 2016 to May 2017. Measurement of body compartments was evaluated with volume assessment software before and after NT. A radiologist blinded to the patient outcome assessed the areas of skeletal muscle, total adipose tissue, and visceral adipose tissue through a standardized protocol. Exposures: Receipt of NT. Main Outcomes and Measures: Achievement of pancreatic resection at surgical exploration after the receipt of NT. Results: Of the 193 patients with complete radiologic imaging available after NT, 96 (49.7%) were women; mean (SD) age at diagnosis was 64 (11) years. Most patients received combined therapy with fluorouracil, irinotecan, oxaliplatin, leucovorin, and folic acid (124 [64.2%]) and 86 (44.6%) received chemoradiotherapy as well. The median interval between pre-NT and post-NT imaging was 6 months (interquartile range [IQR], 4-7 months). All body compartments significantly changed. The adipose compound decreased (median total adipose tissue area from 284.0 cm2; IQR, 171.0-414.0 to 250.0 cm2; IQR, 139.0-363.0; P < .001; median visceral adipose tissue area from 115.2 cm2; IQR, 59.9-191.0 to 97.7 cm2; IQR, 48.0-149.0 cm2; P < .001), whereas the lean mass slightly improved (median skeletal muscle from 122.1 cm2; IQR, 99.3-142.0 to 123 cm2; IQR 104.8-152.5 cm2; P = .001). Surgical resection was achievable in 136 (70.5%) patients. Patients who underwent resection had experienced a 5.9% skeletal muscle area increase during NT treatment, whereas those who did not undergo resection had a 1.7% decrease (P < .001). Conclusions and Relevance: Patients with PC experience a significant loss of adipose tissue during neoadjuvant chemotherapy, but no muscle wasting. An increase in muscle tissue during NT is associated with resectability.