Radiology
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Purpose To analyze how automatic segmentation translates in accuracy and precision to morphology and relaxometry compared with manual segmentation and increases the speed and accuracy of the work flow that uses quantitative magnetic resonance (MR) imaging to study knee degenerative diseases such as osteoarthritis (OA). Materials and Methods This retrospective study involved the analysis of 638 MR imaging volumes from two data cohorts acquired at 3.0 T: (a) spoiled gradient-recalled acquisition in the steady state T1ρ-weighted images and (b) three-dimensional (3D) double-echo steady-state (DESS) images. A deep learning model based on the U-Net convolutional network architecture was developed to perform automatic segmentation. ⋯ Average correlations between manual and automatic quantification of T1ρ and T2 values were 0.8233 and 0.8603, respectively, and 0.9349 and 0.9384 for volume and thickness, respectively. Longitudinal precision of the automatic method was comparable with that of the manual one. Conclusion U-Net demonstrates efficacy and precision in quickly generating accurate segmentations that can be used to extract relaxation times and morphologic characterization and values that can be used in the monitoring and diagnosis of OA. © RSNA, 2018 Online supplemental material is available for this article.
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Purpose To measure in vivo liver stiffness by using US time-harmonic elastography in a cohort of pediatric patients who were overweight to extremely obese with nonalcoholic fatty liver disease (NAFLD) and to evaluate the diagnostic value of time-harmonic elastography for differentiating stages of fibrosis associated with progressive disease. Materials and Methods In this prospective study, 67 consecutive adolescents (age range, 10-17 years; mean body mass index, 34.7 kg/m2; range, 21.4-50.4 kg/m2) with biopsy-proven NAFLD were enrolled. Liver stiffness was measured by using time-harmonic elastography based on externally induced continuous vibrations of 30 Hz to 60 Hz frequency and real-time B-mode-guided wave profile analysis covering tissue depths of up to 14 cm. ⋯ The best liver stiffness cutoffs were 1.52 m/sec for at least stage F1, 1.62 m/sec for at least stage F2, and 1.64 m/sec for at least stage F3. Conclusion US time-harmonic elastography allows accurate detection of moderate fibrosis even in pediatric patients with extreme obesity. Larger clinical trials are warranted to confirm the accuracy of US time-harmonic elastography.
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Purpose To characterize the spatial distribution of cervical cord T1-weighted hypointense lesions in patients with multiple sclerosis (MS) and analyze their association with cord atrophy and disability. Materials and Methods For this prospective study that took place between 2014 and 2016, 3.0-T high-resolution T1-weighted cervical cord magnetic resonance (MR) images and clinical evaluations were obtained from 82 patients with relapsing-remitting MS (RRMS), 33 patients with secondary progressive MS (SPMS), 25 patients with primary progressive MS (PPMS), and 35 sex-matched healthy control participants. Hypointense cord lesions on T1-weighted imaging were identified and corresponding lesion masks were produced. ⋯ Cord atrophy (r value range, -0.24 to -0.48; P < .001) and T1-weighted hypointense cord lesion extent (r value range, 0.36-0.42; P < .001) were correlated with clinical disability. Conclusion Hypointense lesions at T1-weighted imaging were observed in the cervical spinal cord of the majority of patients with MS and more widespread in progressive than in relapsing MS phenotypes. Both T1-weighted hypointense cord lesions and atrophy correlated with patient clinical disability.
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Purpose To evaluate the value of preoperative axillary ultrasonography (US) for preventing unnecessary axillary lymph node dissection after sentinel lymph node (SLN) biopsy in a large series of patients with early-stage breast cancers treated with both breast-conserving surgery and SLN biopsy. Materials and Methods From March 2009 to February 2013, 1802 patients who underwent breast-conserving surgery for clinical T1-2/N0 cancers and SLN biopsy with or without axillary lymph node dissection were included. Preoperative axillary US results and clinical-pathologic variables were compared according to the status of non-SLN metastasis. ⋯ Among 1284 patients with negative axilla at US and clinical T1 stage cancer, 1254 (97.7%) did not have non-SLN metastasis and 30 (2.3%) had non-SLN metastasis. Conclusion Preoperative axillary US results and clinical T stage are associated with the status of non-SLN metastasis in patients with early breast cancer. The results of this study suggest that preoperative axillary US can help select patients at minimal risk of non-SLN metastasis, for whom axillary lymph node dissection can be omitted. © RSNA, 2018 Online supplemental material is available for this article.
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History In November 2012, a previously healthy 31-year-old woman was admitted to our hospital with a 2-month history of right-sided numbness, diplopia, and intermittent nausea and dizziness. She did not have a history of fever, weight loss, headache, photophobia, seizure, or extremity weakness. Physical examination revealed left abduction limitation and right-sided hypoesthesia. ⋯ MR images were obtained again in July 2015 ( Fig 4 ) and February 2016 ( Fig 5 ). The patient underwent biopsy of the right frontal lobe, and a histopathologic examination was performed in August 2015. Afterward, her condition worsened, and she died in September 2016. [Figure: see text][Figure: see text][Figure: see text] [Figure: see text][Figure: see text].