Improved 3D DESS MR neurography of the lumbosacral plexus with deep learning and geometric image combination reconstruction.

OBJECTIVE: To evaluate the impact of deep learning (DL) reconstruction in enhancing image quality and nerve conspicuity in LSP MRN using DESS sequences. Additionally, a geometric image combination (GIC) method to improve DESS signals' combination was proposed. MATERIALS AND METHODS: Adult patients undergoing 3.0 Tesla LSP MRN with DESS were prospectively enrolled. The 3D DESS echoes were separately reconstructed with and without DL and DL-GIC combined reconstructions. In a subset of patients, 3D T2-weighted short tau inversion recovery (STIR-T2w) sequences were also acquired. Three radiologists rated 4 image stacks ('DESS S2', 'DESS S2 DL', 'DESS GIC DL' and 'STIR-T2w DL') for bulk motion, vascular suppression, nerve fascicular architecture, and overall nerve conspicuity. Relative SNR, nerve-to-muscle, -fat, and -vessel contrast ratios were measured. Statistical analysis included ANOVA and Wilcoxon signed-rank tests. p < 0.05 was considered statistically significant. RESULTS: Forty patients (22 females; mean age = 48.6 ± 18.5 years) were enrolled. Quantitatively, 'DESS GIC DL' demonstrated superior relative SNR (p < 0.001), while 'DESS S2 DL' exhibited superior nerve-to-background contrast ratio (p value range: 0.002 to < 0.001). Qualitatively, DESS provided superior vascular suppression and depiction of sciatic nerve fascicular architecture but more bulk motion as compared to 'STIR-T2w DL'. 'DESS GIC DL' demonstrated better nerve visualization for several smaller, distal nerve segments than 'DESS S2 DL' and 'STIR-T2w DL'. CONCLUSION: Application of a DL reconstruction with geometric image combination in DESS MRN improves nerve conspicuity of the LSP, especially for its smaller branch nerves.

Hourglass-like constrictions on MRI are common in electromyography-confirmed cases of neuralgic amyotrophy (Parsonage-Turner syndrome): A tertiary referral center experience.

INTRODUCTION/AIMS: Hourglass-like constrictions (HGCs) of involved nerves in neuralgic amyotrophy (NA) (Parsonage-Turner syndrome) have been increasingly recognized with magnetic resonance neurography (MRN). This study sought to determine the sensitivity of HGCs, detected by MRN, among electromyography (EMG)-confirmed NA cases. METHODS: This study retrospectively reviewed records of patients with the clinical diagnosis of NA, and with EMG confirmation, who underwent 3-Tesla MRN within 90 days of EMG at a single tertiary referral center between 2011 and 2021. "Severe NA" positive cases were defined by a clinical diagnosis and specific EMG criteria: fibrillation potentials or positive sharp waves, along with motor unit recruitment (MUR) grades of "discrete" or "none." On MRN, one or more HGCs, defined as focally decreased nerve caliber or diffusely beaded appearance, was considered "imaging-positive." Post hoc inter-rater reliability for HGCs was measured by comparing the original MRN report against subsequent blinded interpretation by a second radiologist. RESULTS: A total of 123 NA patients with 3-Tesla MRN performed within 90 days of EMG were identified. HGCs were observed in 90.2% of all NA patients. In "severe NA" cases, based on the above EMG criteria, HGC detection resulted in a sensitivity of 91.9%. Nerve-by-nerve analysis (183 nerve-muscle pairs, nerves assessed by MRN, muscles assessed by EMG) showed a sensitivity of 91.0%. The second radiologist largely agreed with the original HGC evaluation, (94.3% by subjects, 91.8% by nerves), with no significant difference between evaluations (subjects: χ2 = 2.27, P = .132, nerves: χ2 = 0.98, P = .323). DISCUSSION: MRN detection of HGCs is common in NA.

Imaging of the Hip Prior to Replacement: What the Surgeon Wants to Know.

Total hip arthroplasty is an effective treatment for severe degenerative arthritis and is increasingly being used. Radiography is the primary modality for the initial diagnosis of osteoarthritis and preoperative planning. Additional radiographic views may include the spine and lower extremities in order to optimize implant positioning for the individual patient. Computed tomography is sometimes used for preoperative planning and intraoperative robotic assistance. Magnetic resonance imaging and diagnostic ultrasound is generally reserved for patients without obvious arthritis. Ultrasound-guided injections may provide diagnostic and/or therapeutic benefits.

Unsolicited Invitations to Scientific Meetings: Radiologists' Experience.

OBJECTIVE: Unsolicited invitations to speak at medical meetings have proliferated as a type of spam email and phishing strategy to scam unsuspecting victims. We sought to determine the prevalence of such invitations to questionable meetings and determine the factors associated with receiving such solicitations. MATERIALS AND METHODS: Data was collected for the number of speakers' invitations received over a 2-week period (April -May 2023) by radiologists of different subspecialties, academic ranks, and histories of publications and speaking engagements in the past 2-5 years. We analyzed the number of invitations received based on the variables. RESULTS: Thirty-three of 45 (73.3%) faculty members received 188 inappropriate invitation emails in the 2-week observation period. The mean number of invitation emails was 4.13 for each faculty (SD: 5.03, range 0-20). There was no correlation between the number of invitations and radiologists' subspecialty, academic rank (3.8 ± 5, 3.0 ± 4, and 5.5 ± 5.7 invitations for full, associate, and assistant professors respectively) and previous legitimate speaker invites. Only 6 (3.2%) out of 188 invitations to speak sent to radiologists were for radiology-related meetings. Having more than 10 publications since 2022 was associated with a 5.0 (1.2, 19.4) times higher odds of receiving more than 4 solicitations. CONCLUSIONS: A total of 73.3% of the faculty surveyed received unsolicited invitations to meetings in the 2-week study period and over 96% of the invitations were unrelated to their field of practice. Our results show that publications since 2022 was the most significant factor associated with receiving more solicitations. CLINICAL RELEVANCE/APPLICATION: Invitations to questionable meetings targeting radiologists are frequent and often are unrelated to their specialties. The risk factors for receiving the invitations are unclear. Understanding these risk factors may enable educators especially junior investigators, to be better prepared to appropriately address such solicitations.

Early perioperative magnetic resonance findings in patients with foot drop following total hip Arthroplasty: A descriptive case-series.

PURPOSE: This study aims to characterize iatrogenic sciatic nerve injury patterns in the early, perioperative period following posterior-approach total hip arthroplasty (THA) with magnetic resonance imaging (MRI). METHODS: This was an IRB-approved retrospective analysis of patients acquired from a longitudinal, single site radiology database of patients who underwent MRI for "foot drop" within 4 weeks following posterior-approach THA surgery, over a 20-year period. RESULTS: MRI exams from 51 patients (mean age 62 years; 32 females) who met inclusion criteria were evaluated. Mean time to MRI was 2.4 days. Of 51 patients, 43 underwent primary THA, 6 revision THA and 2 explantation with antibiotic spacer placement. Ten exams revealed a normal appearance of the sciatic nerve. Nineteen showed compression of the sciatic nerve by edema or a fluid collection, without intrinsic nerve abnormality. Fifteen demonstrated perineural tethering or scar/granulation tissue encasement of the nerve, and in half of these cases the sciatic nerve was enlarged and/or hyperintense on fluid-sensitive sequences. Six patients had sciatic nerve compression secondary to quadratus femoris retraction. Six patients had complete resolution of the foot drop at a mean follow-up of 37.3 months following surgery, and in these cases the sciatic nerve appeared normal on the initial postoperative MRI. Remaining patients all had persistent weakness and paresthesias in the sciatic nerve distribution at a mean follow-up duration of 34.3 months. CONCLUSION: This retrospective case series demonstrates various sciatic nerve injury patterns in the early perioperative period on MRI and proposes a targeted MRI protocol to evaluate the sciatic nerve post THA surgery.

A Novel Hands-on Approach Towards Teaching Diagnostic Radiology Residents MRI Scanning and Physics.

RATIONALE AND OBJECTIVES: Traditional approaches towards teaching magnetic resonance imaging (MRI) scanning and physics have limitations that a hands-on course may help overcome. A dedicated week of MRI instruction may help improve radiology resident confidence and competence. Additional benefits may include improved physician-technologist communication and accelerated mastery of MRI safety. MATERIALS AND METHODS: Surveys and tests were approved by our Program Evaluation Committee and administered at the beginning and at the end of this one-week course. The course consisted of protected reading time as well as practice scanning with a research magnet and assisting with clinical scanning under the close supervision of a licensed MRI technologist. Eighteen senior residents (nine third-year and nine fourth-year) participated in this course during its first year. RESULTS: Few residents had previous experience with MRI physics, scanning, or research prior to residency. After this course, mean resident confidence increased by 0.47 points (3.33 vs 2.86; p=0.01) on a five-point Likert scale. Understanding of MRI physics, as measured by pre- and post-tests, increased by 22% (0.72 vs 0.50; p<0.01), corresponding to a large effect size of 1.29 (p<0.001). Resident feedback reported that this course was efficacious (5/5), engaging (4.9/5), and had optimal faculty oversight. The most highly rated component of the course was the opportunity to experiment with the research MR scanner (5/5). CONCLUSION: A dedicated week of MRI education was highly rated by residents and associated with improvements in confidence and understanding, suggesting a positive correlation between confidence and competence. Additional metrics, such as trends in scores on the American Board of Radiology's Core Examination over the next several years, may further support the apparent benefits of this hands-on MR course.

Three-dimensional MR Neurography of the Brachial Plexus: Vascular Suppression with Low-dose Ferumoxytol.

Background The efficacy of ferumoxytol, an ultrasmall superparamagnetic iron oxide particle for three-dimensional (3D) MR neurography, has yet to be evaluated. Purpose To evaluate the effects of low-dose ferumoxytol for vascular suppression and nerve visualization in 3D brachial plexus MR neurography as a pilot study. Materials and Methods Volunteers without anemia were prospectively enrolled in July 2021. Brachial plexus MR neurography was performed 30 minutes following infusion of 25% of the standard (510 mg of iron) therapeutic ferumoxytol dose with use of a 3D short-tau inversion recovery T2-weighted fast spin-echo sequence. The 3D fast spin-echo was acquired with and without the use of additional flow suppression techniques. Two musculoskeletal radiologists qualitatively evaluated examinations for the degree of vascular suppression (0-3, none to complete), nerve visualization (0-2, none to full), and motion artifact (0-4, none to severe). Nerve-to-fat, muscle, or vessel contrast ratios were calculated with use of manually drawn regions of interests. Comparisons of the proportion of scans with adequate image quality (vascular suppression, 3; nerve visualization, 1, 2; motion artifacts, 0, 1) were made with use of the McNemar test. Comparisons of quantitative contrast ratios were performed with use of Wilcoxon signed rank tests. P < .05 was deemed statistically significant. Results There were 12 volunteers (mean age, 25 years ± 3; six women) evaluated. The scans with adequate vascular suppression increased from 0% to 98% with and without ferumoxytol, respectively (P < .001). All individual nerve assessments of adequate nerve visualization increased from 4%-63% to 36%-100% without and with ferumoxytol, respectively (P < .001-.010), while motion artifacts were unchanged (from 33% to 52%, P = .212). Quantitatively, nerve-to-vessel contrast ratios increased from 0.6 without to 7.6 with ferumoxytol (P < .001). The addition of flow suppression did not change nerve-to-vessel contrast ratio quantitatively (from 7.5 to 8.4, P > .99) following ferumoxytol. Conclusion Low-dose ferumoxytol improved vascular suppression and nerve visualization in three-dimensional MR neurography of the brachial plexus compared to imaging without ferumoxytol. © RSNA, 2022.

Spotty Bone Marrow: A Frequent MRI Finding in the Feet of Ballet Dancers.

INTRODUCTION: Bone marrow signal abnormalities on magnetic resonance imaging (MRI) are common in athletes. However, few studies evaluate the MRI appearance of bone marrow in the feet of ballet dancers. Our study aims to describe the "spotty bone marrow" (SBM) pattern in the tarsal bones of a cohort of ballet dancers, establishing its prevalence, distribution, potential associations, and evolution.
Methods: Eighty-six MRIs of 68 ankles in 56 ballet dancers were retrospectively reviewed for mar- row signal alterations, which were classified as focal or SBM (defined as patchy fluid-sensitive signal hyperintensity spanning more than one location or tarsal bone). When SBM involved the talus, its anatomic distribution in the bone and morphologic pattern were recorded. Additional osseous and soft tissue findings were documented. For subjects with more than one MRI of the same ankle, the SBM's evolution was monitored.
Results: Spotty bone marrow was identified in 44 ankles (65%). Spotty bone marrow was isolated to the talus (44%), present in all tarsal bones (25%), or distributed between the talus and one to three other tarsal bones (31%). In the talus, The SBM involved the entire bone (65%), the neck and body (31%), or the head and neck (4%). The SBM most commonly showed a random morphologic pattern (87%) but occasionally showed a peripheral predominance (13%). There was no statistically significant difference in the prevalence of other pathologies in ankles with and without SBM. In eight ankles with a follow-up MRI, the SBM worsened in one, remained stable in two, and improved in five ankles. None progressed to a stress fracture.
Conclusion: Spotty bone marrow is an MRI finding frequently encountered in ballet dancers. It is usually self-limiting and should not be misinterpreted as a more aggressive pathology.

Pediatric chest wall masses: spectrum of benign findings on ultrasound.

A palpable finding along the chest wall is a frequent indication for pediatric US. Accurate identification of benign lesions can reassure families and appropriately triage children who need follow-up, cross-sectional imaging, or biopsy. In this pictorial essay, we review chest wall anatomy, illustrate US techniques and discuss key US imaging features of common benign lesions and normal variants.

Chondroid lipoma: multimodality imaging in a 9-year-old female.

Chondroid lipomas are rare, benign lipomatous tumors that occur most frequently in adults during the fourth decade of life. While a female predominance was observed in the initial series of 20 cases described in 1993, the subsequent 49 reported cases do not support a strong gender predilection. We report a case of a chondroid lipoma presenting in a 9-year-old female as a painless, enlarging, left gluteal mass. This is the second case to be reported in the first decade of life and the fourth pediatric case reported in the literature (age < 21). We review the imaging and pathology findings as well as present a comprehensive review of the current literature.

Imaging findings of spinal brown tumors: a rare but important cause of pathologic fracture and spinal cord compression.

Brown tumors rarely develop in the spine, and neurological compromise is exceedingly uncommon. There is a growing body of literature describing brown tumors that involve the spine, but few emphasize the radiographic findings. In the present case, we illustrate the development and progression of biopsy-proven brown tumors leading to neurological compromise through radiographs, computed tomography, magnetic resonance, and nuclear imaging acquired over a 4-year span.

Development and utilization of a web-based application as a robust radiology teaching tool (radstax) for medical student anatomy teaching.

Rationale and Objectives: The primary role of radiology in the preclinical setting is the use of imaging to improve students' understanding of anatomy. Many currently available Web-based anatomy programs include either suboptimal or overwhelming levels of detail for medical students.Our objective was to develop a user-friendly software program that anatomy instructors can completely tailor to match the desired level of detail for their curriculum, meets the unique needs of the first- and the second-year medical students, and is compatible with most Internet browsers and tablets.Materials and Methods: RadStax is a Web-based application developed using free, open-source, ubiquitous software. RadStax was first introduced as an interactive resource for independent study and later incorporated into lectures. First- and second-year medical students were surveyed for quantitative feedback regarding their experience.Results: RadStax was successfully introduced into our medical school curriculum. It allows the creation of learning modules with labeled multiplanar (MPR) image sets, basic anatomic information, and a self-assessment feature. The program received overwhelmingly positive feedback from students. Of 115 students surveyed, 87.0% found it highly effective as a study tool and 85.2% reported high user satisfaction with the program.Conclusions: RadStax is a novel application for instructors wishing to create an atlas of labeled MPR radiologic studies tailored to meet the specific needs their curriculum. Simple and focused, it provides an interactive experience for students similar to the practice of radiologists.This program is a robust anatomy teaching tool that effectively aids in educating the preclinical medical student.