Diagnostic performance of deep learning-based reconstruction algorithm in 3D MR neurography

OBJECTIVE The study aims to evaluate the diagnostic performance of deep learning-based reconstruction method (DLRecon) in 3D MR neurography for assessment of the brachial and lumbosacral plexus. MATERIALS AND METHODS Thirty-five exams (18 brachial and 17 lumbosacral plexus) of 34 patients undergoing routine clinical MR neurography at 1.5 T were retrospectively included (mean age: 49 ± 12 years, 15 female). Coronal 3D T2-weighted short tau inversion recovery fast spin echo with variable flip angle sequences covering plexial nerves on both sides were obtained as part of the standard protocol. In addition to standard-of-care (SOC) reconstruction, k-space was reconstructed with a 3D DLRecon algorithm. Two blinded readers evaluated images for image quality and diagnostic confidence in assessing nerves, muscles, and pathology using a 4-point scale. Additionally, signal-to-noise ratio (SNR) and contrast-to-noise ratios (CNR) between nerve, muscle, and fat were measured. For comparison of visual scoring result non-parametric paired sample Wilcoxon signed-rank testing and for quantitative analysis paired sample Student's t-testing was performed. RESULTS DLRecon scored significantly higher than SOC in all categories of image quality (p < 0.05) and diagnostic confidence (p < 0.05), including conspicuity of nerve branches and pathology. With regard to artifacts there was no significant difference between the reconstruction methods. Quantitatively, DLRecon achieved significantly higher CNR and SNR than SOC (p < 0.05). CONCLUSION DLRecon enhanced overall image quality, leading to improved conspicuity of nerve branches and pathology, and allowing for increased diagnostic confidence in evaluation of the brachial and lumbosacral plexus

Application of deep learning-based image reconstruction in MR imaging of the shoulder joint to improve image quality and reduce scan time

OBJECTIVES To compare the image quality and diagnostic performance of conventional motion-corrected periodically rotated overlapping parallel line with enhanced reconstruction (PROPELLER) MRI sequences with post-processed PROPELLER MRI sequences using deep learning-based (DL) reconstructions. METHODS In this prospective study of 30 patients, conventional (19 min 18 s) and accelerated MRI sequences (7 min 16 s) using the PROPELLER technique were acquired. Accelerated sequences were post-processed using DL. The image quality and diagnostic confidence were qualitatively assessed by 2 readers using a 5-point Likert scale. Analysis of the pathological findings of cartilage, rotator cuff tendons and muscles, glenoid labrum and subacromial bursa was performed. Inter-reader agreement was calculated using Cohen's kappa statistic. Quantitative evaluation of image quality was measured using the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). RESULTS Mean image quality and diagnostic confidence in evaluation of all shoulder structures were higher in DL sequences (p value = 0.01). Inter-reader agreement ranged between kappa values of 0.155 (assessment of the bursa) and 0.947 (assessment of the rotator cuff muscles). In 17 cases, thickening of the subacromial bursa of more than 2 mm was only visible in DL sequences. The pathologies of the other structures could be properly evaluated by conventional and DL sequences. Mean SNR (p value = 0.01) and CNR (p value = 0.02) were significantly higher for DL sequences. CONCLUSIONS The accelerated PROPELLER sequences with DL post-processing showed superior image quality and higher diagnostic confidence compared to the conventional PROPELLER sequences. Subacromial bursa can be thoroughly assessed in DL sequences, while the other structures of the shoulder joint can be assessed in conventional and DL sequences with a good agreement between sequences. KEY POINTS • MRI of the shoulder requires long scan times and can be hampered by motion artifacts. • Deep learning-based convolutional neural networks are used to reduce image noise and scan time while maintaining optimal image quality. The radial k-space acquisition technique (PROPELLER) can reduce the scan time and has potential to reduce motion artifacts. • DL sequences show a higher diagnostic confidence than conventional sequences and therefore are preferred for assessment of the subacromial bursa, while conventional and DL sequences show comparable performance in the evaluation of the shoulder joint

The Effect of Paraspinal Fatty Muscle Infiltration and Cumulative Lumbar Spine Degeneration on the Outcome of Patients with Lumbar Spinal Canal Stenosis: Analysis of the Lumbar Stenosis Outcome Study (LSOS) Data

STUDY DESIGN - Prospective. OBJECTIVE To investigate the influence of paraspinal fatty muscle infiltration (FMI) and cumulative lumbar spine degeneration as assessed by magnetic resonance imaging (MRI) on long-term clinical outcome measures in patients with lumbar spinal canal stenosis (LSCS) of the Lumbar Stenosis Outcome Study (LSOS) cohort. SUMMARY OF BACKGROUND DATA Past studies have tried to establish correlations of morphologic imaging findings in LSCS with clinical endpoints. However, the impact of FMI and overall lumbar spinal degeneration load has not been examined yet. METHODS Patients from the LSOS cohort with moderate to severe LSCS were included. Two radiologists assessed the degree of LSCS as well as cumulative degeneration of the lumbar spine. FMI was graded using the Goutallier scoring system. Spinal Stenosis Measure (SSM) was used to measure the severity level of symptoms and disability. European Quality of Life 5 Dimensions 3 Level Version (EQ-5D-3L) was used to measure health-related quality of life. RESULTS The non-surgically treated group consisted of 116 patients (age 74.8±8.5 y), whereas the surgically treated group included 300 patients (age 72.3±8.2 y). Paraspinal FMI was significantly different between the groups (54.3% vs. 32.0% for Goutallier grade ≥2; P0.05). CONCLUSION FMI is associated with higher disability and worse health-related quality of life of LSCS patients in the LSOS cohort. There was no significant association between total cumulative lumbar spine degeneration and the outcome of either surgically or non-surgically treated patients. LEVEL OF EVIDENCE - Level 3

Surgical Resection of a Reversed Palmaris Longus Muscle Causing Chronic Exertional Compartment Syndrome in a Competitive Swimmer: A Case Report

The palmaris longus is a superficial muscle located on the volar side of the forearm. It usually arises from the medial epicondyle of the humerus and inserts into the palmar aponeurosis of the wrist. However, the palmaris longus is one of the most variable muscles in the human body. The most frequent anatomic variation is complete agenesis, which is found in up to 25% of the population.9,12 Other variations include reversed, duplicated, bifid, or hypertrophied palmaris longus muscles, which can be of clinical significance by causing effort-related pain with or without median or ulnar nerve paresthesia.1,3,4,11 According to the literature, treatment of these conditions consists of excision of the anomalous muscle, decompressive fasciotomy, median or ulnar nerve release, or a combination of the aforementioned.3 We report a case in which a reversed palmaris longus muscle caused exertional forearm pain without median or ulnar nerve paresthesia in an adolescent competitive swimmer. Treatment consisted of surgical excision of the anomalous muscle, which led to full relief of pain

Comparison of AI-powered 3D automated ultrasound tomography with standard handheld ultrasound for the visualization of the hands-clinical proof of concept

OBJECTIVE To assess the ability of a newly developed AI-powered ultrasound 3D hand scanner to visualize joint structures in healthy hands and detect degenerative changes in cadaveric hands. MATERIALS AND METHODS Twelve individuals (6 males, 6 females, age 43.5 ± 17.8 years) underwent four scans with the 3D ultrasound tomograph (right and left hand, dorsal and palmar, respectively) as well as four sets of handheld ultrasound of predefined anatomic regions. The 3D ultrasound tomographic images and the standard handheld ultrasound images were assessed by two radiologists with regard to visibility of bone contour, joint capsule and space, and tendons. In addition, three cadaveric hands were scanned with the 3D ultrasound tomograph and CT. RESULTS Mean scan time for both hands was significantly faster with handheld ultrasound (10 min 30 s ± 95 s) compared to 3D ultrasound tomography (32 min 9 s ± 6 s; p < 0.001). Interreader and intermodality agreement was moderate (0.4 < κ ≤ 0.6) to substantial (0.6 < κ ≤ 0.8). Overall visibility of joint structures was comparable between the modalities at the level of the wrist (p = 0.408), and significantly better with handheld ultrasound at the level of the finger joints and the thumb (both p < 0.001). The 3D ultrasound tomograph was able to detect osteophytes in cadaveric hands which were confirmed by CT. CONCLUSION The AI-powered 3D ultrasound tomograph was able to visualize joint structures in healthy hands and singular osteophytes in cadaveric hands. Further technical improvements are necessary to shorten scan times and improve automated scanning of the finger joints and the thumb

Comparison of Muscle Fat Fraction Measurements in the Lower Spine Musculature with Non-Contrast-Enhanced CT and Different MR Imaging Sequences

Purpose: To assess whether two-point Dixon (TPD) MRI, true fast imaging with steady-state free precession (TRUFI) MRI and non-contrast-enhanced CT (NECT) can accurately measure muscle fat fraction (FF) in the autochthonous back muscles (AM) and the psoas muscle (PM) compared to multi-point Dixon (MPD) MRI. Method: 29 oncological patients who received MRI including MPD, TPD and NECT imaging in a period of three months were analyzed retrospectively. A sub-cohort of 16 patients additionally underwent TRUFI MRI and were included in a sub-analysis. Region of interest (ROI) measurements for each muscle compartment of the AM and PM were conducted by two examiners. Additionally, the Goutallier classification was used to quantify the amount of fatty infiltration of each muscle. Intermodality correlations were assessed with the Pearson correlation coefficient (r), and interreader and intrareader agreements with the intraclass correlation coefficient (ICC). Results: Good intermodality correlations were found for NECT (r = 0.969), TPD (r = 0.942) and TRUFI (r = 0.904, all P < 0.001) when assessing FF in the AM and slightly lower in the PM. Interreader agreement showed good correlations and low median deviations (1.1 - 4.1 %, depending on the modality). The Goutallier classification of the AM showed good separation between grades with substantial interreader agreement (κ = 0.627, P < 0.001). Conclusions: ROI measurements of the AM in NECT, TPD and TRUFI highly correlate with muscle FF measurements in MPD MRI and may be used to assess sarcopenia in oncological patients. Keywords: Body Composition; Computed Tomography; Fat Fraction; Magnetic Resonance Imaging; Muscles; Sarcopenia

Impact of acceleration on bone depiction quality by ultrashort echo time magnetic resonance bone imaging sequences in medication-related osteonecrosis of the jaw

Objectives To assess the impact on bone depiction quality by decreasing number of radial acquisitions (RA) of a UTE MR bone imaging sequence in MRONJ. Material and methods UTE MR bone imaging sequences using pointwise encoding time reduction with RA (PETRA) with 60'000, 30'000 and 10'000 RA were acquired in 16 patients with MRONJ and 16 healthy volunteers. Blinded readout sessions were performed by two radiologists. Qualitative analysis compared the detection of osteolytic lesions and productive bony changes in the PETRA sequences of the patients with MRONJ. Quantitative analysis assessed the differences in image artifacts, contrast-to-noise ratio (CNR) and image noise. Results Acquisition times were reduced from 315 to 165 and 65 s (60'000, 30'000, 10'000 RA, respectively), resulting in a fewer number of severe motion artifacts. Bone delineation was increasingly blurred when reducing the number of RA but without any trade-off in terms of diagnostic performance. Interreader agreement for the detection of pathognomonic osteolysis was moderate (κ = 0.538) for 60'000 RA and decreased to fair (κ = 0.227 and κ = 0.390) when comparing 30'000 and 10'000 RA, respectively. Image quality between sequences was comparable regarding CNR, image noise and artifact dimensions without significant differences (all P > 0.05). Conclusions UTE MR bone imaging sequences with a lower number of RA provide sufficient image quality for detecting osteolytic lesions and productive bony changes in MRONJ subjects at faster acquisition times compared to the respective standard UTE MR bone imaging sequence

The impact of non-thermal injuries in combined burn trauma: A retrospective analysis over the past 35 years

Introduction Combined burn trauma is rather uncommon and frequently difficult to manage. Historically combined burn trauma contributed to high mortality rates in severely injured patients. The purpose of this study was to determine the incidence, mechanisms and impact of non-thermal injuries in patients with severe burns. Methods The charts of 2536 patients admitted to the Burn Center of the University Hospital Zurich between 1977 and 2013 were reviewed and retrospectively analyzed. Patients with additional injuries were identified and analyzed statistically. Results Over 35 years from 1977 to 2013 a total of 100 burn patients (3.9%) with additional trauma were identified. Motor vehicle crash was the most common mechanism of injury (44%) from 1977 to 1995, compared to electrical injury (33%) from 1996 to 2013. Skeletal trauma including spinal and pelvic injury was the most common form (71%). Additional thoracic or abdominal trauma represented the highest risk factor for in-hospital mortality (adjusted RR 2.2, 95% CI 0.6–7.6). However, after 1995 the presence of any form of additional injury did not have a significant impact on in-hospital mortality (unadjusted RR 0.97, 95% CI 0.5–1.7, p = 0.914). Conclusions Concomitant trauma did not reveal a significant impact on in-hospital mortality in our burn center recently. Retrospectively, trauma mechanisms shifted from motor vehicle crashes to electrical injuries in our population. Safety measures for motor vehicles and adequate emergency room algorithms seem to have contributed to a reduction of severity of injury and mortality. Keywords Abdominal injury Electric injury Fracture Trauma severity index Mortalit