Publications

Background Current terms used to describe the MRI findings for musculoskeletal infections are nonspecific and inconsistent. Purpose To develop and validate an MRI-based musculoskeletal infection classification and scoring system. Materials and Methods In this retrospective cross-sectional internal validation study, a Musculoskeletal Infection Reporting and Data System (MSKI-RADS) was designed. Adult patients with radiographs and MRI scans of suspected extremity infections with a known reference standard obtained between June 2015 and May 2019 were included. The scoring categories were as follows: 0, incomplete imaging; I, negative for infection; II, superficial soft-tissue infection; III, deeper soft-tissue infection; IV, possible osteomyelitis (OM); V, highly suggestive of OM and/or septic arthritis; VI, known OM; and NOS (not otherwise specified), nonspecific bone lesions. Interreader agreement for 20 radiologists from 13 institutions (intraclass correlation coefficient [ICC]) and true-positive rates of MSKI-RADS were calculated and the accuracy of final diagnoses rendered by the readers was compared using generalized estimating equations for clustered data. Results Among paired radiographs and MRI scans from 208 patients (133 male, 75 female; mean age, 55 years ± 13 [SD]), 20 were category I; 34, II; 35, III; 30, IV; 35, V; 18, VI; and 36, NOS. Moderate interreader agreement was observed among the 20 readers (ICC, 0.70; 95% CI: 0.66, 0.75). There was no evidence of correlation between reader experience and overall accuracy (P = .94). The highest true-positive rate was for MSKI-RADS I and NOS at 88.7% (95% CI: 84.6, 91.7). The true-positive rate was 73% (95% CI: 63, 80) for MSKI-RADS V. Overall reader accuracy using MSKI-RADS across all patients was 65% ± 5, higher than final reader diagnoses at 55% ± 7 (P < .001). Conclusion MSKI-RADS is a valid system for standardized terminology and recommended management of imaging findings of peripheral extremity infections across various musculoskeletal-fellowship-trained reader experience levels. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Schweitzer in this issue.

BACKGROUND/OBJECTIVE: Radiofrequency ablation (RFA) has been increasingly used as an alternative to surgery in patients with primary hyperparathyroidism who are unable or unwilling to have surgery.

CASE REPORT: We present a case of a 64-year-old woman who had surgery for primary hyperparathyroidism complicated by osteoporosis. Preoperative imaging with 4-dimensional computed tomography scan suggested multigland disease; however, she had persistent hyperparathyroidism after parathyroid exploration. Reevaluation of her imaging studies with ultrasound (US) and US-guided fine needle aspiration for parathyroid hormone washout led to identification of an intrathyroidal parathyroid adenoma that was successfully treated by RFA followed by ethanol injection.

DISCUSSION: The case illustrates the utility of US and US-guided fine needle aspiration for the identification of intrathyroidal parathyroid adenomas, as well as successful treatment of a patient who had failed parathyroid surgery, with a combination of both radiofrequency and percutaneous ethanol ablation, a novel technique.

CONCLUSION: RFA, with or without ethanol ablation, can be considered as an alternative to surgery for patients with persistent hyperparathyroidism after parathyroidectomy.

Percutaneous image-guided ablation techniques are a consolidated therapeutic alternative for patients with high preoperative surgical risk for the management of oncological diseases in multiple body districts. Each technique has both pros and cons according to the type of energy delivered, mechanism of action, and site of application. The present article reviews the most recent literature results on ablation techniques applied in the field of genitourinary diseases (kidney, adrenal glands, prostate, and uterus), describing the advantages of the use of each technique and their technical limitations and summarizing the major recommendations from an international consensus meeting. CRITICAL RELEVANT STATEMENT: The article critically evaluates the efficacy and safety of ablation therapies for various genitourinary tract diseases, demonstrating their potential to improve patient outcomes and advance clinical radiology by offering minimally invasive, effective alternatives to traditional surgical treatments. KEY POINTS: Ablation therapies are effective alternatives to surgery for renal cell carcinoma. Ablation techniques offer effective treatment for intermediate-risk prostate cancer. Ablation is a promising tool for adrenal tumor management. Ablation reduces fibroid symptoms and volume, offering an alternative to surgery.

BACKGROUND: The Paris classification categorises colorectal polyp morphology. Interobserver agreement for Paris classification has been assessed at optical colonoscopy (OC) but not CT colonography (CTC). We aimed to determine the following: (1) interobserver agreement for the Paris classification using CTC between radiologists; (2) if radiologist experience influenced classification, gross polyp morphology, or polyp size; and (3) the extent to which radiologist classifications agreed with (a) colonoscopy and (b) a combined reference standard.

METHODS: Following ethical approval for this non-randomised prospective cohort study, seven radiologists from three hospitals classified 52 colonic polyps using the Paris system. We calculated interobserver agreement using Fleiss kappa and mean pairwise agreement (MPA). Absolute agreement was calculated between radiologists; between CTC and OC; and between CTC and a combined reference standard using all available imaging, colonoscopic, and histopathological data.

RESULTS: Overall interobserver agreement between the seven readers was fair (Fleiss kappa 0.33; 95% CI 0.30-0.37; MPA 49.7%). Readers with < 1500 CTC experience had higher interobserver agreement (0.42 (95% CI 0.35-0.48) vs. 0.33 (95% CI 0.25-0.42)) and MPA (69.2% vs 50.6%) than readers with ≥ 1500 experience. There was substantial overall agreement for flat vs protuberant polyps (0.62 (95% CI 0.56-0.68)) with a MPA of 87.9%. Agreement between CTC and OC classifications was only 44%, and CTC agreement with the combined reference standard was 56%.

CONCLUSION: Radiologist agreement when using the Paris classification at CT colonography is low, and radiologist classification agrees poorly with colonoscopy. Using the full Paris classification in routine CTC reporting is of questionable value.

CLINICAL RELEVANCE STATEMENT: Interobserver agreement for radiologists using the Paris classification to categorise colorectal polyp morphology is only fair; routine use of the full Paris classification at CT colonography is questionable.

KEY POINTS: • Overall interobserver agreement for the Paris classification at CT colonography (CTC) was only fair, and lower than for colonoscopy. • Agreement was higher for radiologists with < 1500 CTC experience and for larger polyps. There was substantial agreement when classifying polyps as protuberant vs flat. • Agreement between CTC and colonoscopic polyp classification was low (44%).

OBJECTIVE: To determine the inter-reader reliability and diagnostic performance of classification and severity scales of Neuropathy Score Reporting And Data System (NS-RADS) among readers of differing experience levels after limited teaching of the scoring system.

METHODS: This is a multi-institutional, cross-sectional, retrospective study of MRI cases of proven peripheral neuropathy (PN) conditions. Thirty-two radiology readers with varying experience levels were recruited from different institutions. Each reader attended and received a structured presentation that described the NS-RADS classification system containing examples and reviewed published articles on this subject. The readers were then asked to perform NS-RADS scoring with recording of category, subcategory, and most likely diagnosis. Inter-reader agreements were evaluated by Conger's kappa and diagnostic accuracy was calculated for each reader as percent correct diagnosis. A linear mixed model was used to estimate and compare accuracy between trainees and attendings.

RESULTS: Across all readers, agreement was good for NS-RADS category and moderate for subcategory. Inter-reader agreement of trainees was comparable to attendings (0.65 vs 0.65). Reader accuracy for attendings was 75% (95% CI 73%, 77%), slightly higher than for trainees (71% (69%, 72%), p = 0.0006) for nerves and comparable for muscles (attendings, 87.5% (95% CI 86.1-88.8%) and trainees, 86.6% (95% CI 85.2-87.9%), p = 0.4). NS-RADS accuracy was also higher than average accuracy for the most plausible diagnosis for attending radiologists at 67% (95% CI 63%, 71%) and for trainees at 65% (95% CI 60%, 69%) (p = 0.036).

CONCLUSION: Non-expert radiologists interpreted PN conditions with good accuracy and moderate-to-good inter-reader reliability using the NS-RADS scoring system.

CLINICAL RELEVANCE STATEMENT: The Neuropathy Score Reporting And Data System (NS-RADS) is an accurate and reliable MRI-based image scoring system for practical use for the diagnosis and grading of severity of peripheral neuromuscular disorders by both experienced and general radiologists.

KEY POINTS: • The Neuropathy Score Reporting And Data System (NS-RADS) can be used effectively by non-expert radiologists to categorize peripheral neuropathy. • Across 32 different experience-level readers, the agreement was good for NS-RADS category and moderate for NS-RADS subcategory. • NS-RADS accuracy was higher than the average accuracy for the most plausible diagnosis for both attending radiologists and trainees (at 75%, 71% and 65%, 65%, respectively).

OBJECTIVE: We evaluated whether superficial lymphatic anatomy and functional lymph node drainage are symmetric between the right and left upper extremities of healthy female volunteers, and if handedness is associated with symmetry of superficial lymphatic anatomy.

BACKGROUND: Symmetry of lymphatic anatomy has been assumed historically. This assumption of individual anatomic symmetry is being utilized clinically and in research without validation.

METHODS: 36 normal female volunteers underwent bilateral indocyanine green (ICG) lymphography and lymphoscintigraphy of the upper extremities. Eight collecting vessel pathways of each upper extremity were mapped on ICG lymphography. 13 lymph node groups were visualized on lymphoscintigraphy. Symmetry of lymphatic anatomy and functional drainage were established by comparing the right and left extremities of each participant. Hand dominance was assessed by hand grip strength on a hand dynamometer.

RESULTS: Among the 36 participants, 10 (28%) showed symmetry of all eight upper extremity lymphatic pathways with ICG. However, only 1 (3%) participant demonstrated complete symmetry amongst the 13 lymph node groups. Total symmetry of lymphatic channels was observed on ICG in seven (39%) participants with hand dominance and three (17%) participants without hand dominance (X2 = 2.215, P = 0.137).

CONCLUSION: Lymphatic anatomy and functional drainage of the upper extremities are not consistently symmetric. Functional nodal drainage as demonstrated by lymphoscintigraphy shows less symmetry than anatomic studies of lymphatic channels using ICG. Symmetric lymphatic anatomy does not appear to correlate with hand dominance. These findings challenge the prevailing assumption of left-right lymphatic symmetry.

BACKGROUND: Short-lasting cough-associated headache (CAH) in patients with Chiari I malformation (CMI) is believed to be due to transient worsening of cerebrospinal flow (CSF) obstruction at the foramen magnum. We assessed changes in CSF flow in response to coughing in CMI patients with CAH and compared with those without CAH and healthy participants (HPs) using real-time magnetic resonance imaging.

METHODS: Seventeen CMI patients (12 with CAH, 5 without CAH) and 6 HPs were prospectively assessed using real-time pencil-beam imaging magnetic resonance sequence. A 64-mm length pencil-beam imaging cylinder was placed at the craniocervical junction. CSF stroke volume (SVCSF) was assessed during resting, postcoughing, and relaxation phases via a 90-second scan. SVCSF was measured at 6 levels at 5-mm intervals between 10 and 35 mm below the foramen magnum. During each phase, SVCSF was compared between CMI with and without CAH and HPs and corrected for multiple comparisons.

RESULTS: At multiple consecutive levels, postcoughing SVCSF was significantly lower in CMI with CAH compared with both CMI without CAH and HP (P < 0.05). No differences in postcoughing SVCSF were seen between CMI without CAH and HP. At rest or relaxation phase, no differences in SVCSF were seen between patients with and without CAH but minimal differences were seen between CMI with CAH and HP.

CONCLUSIONS: A decrease in CSF flow after coughing in CMI patients with CAH supports the notion that CAH is caused by transient worsening of CSF flow obstruction at the foramen magnum.

Introduction: Pathologic vertebral fractures are devastating for patients with spinal metastases. However, the mechanical process underlying these fractures is poorly understood, limiting physician's ability to predict which vertebral bodies will fail. Method: Here, we show the development of a damage-based finite element framework producing highly reliable pathologic vertebral strength and stiffness predictions from X-Ray computed tomography (CT) data. We evaluated the performance of specimen-specific material calibration vs. global material calibration across osteosclerotic, osteolytic, and mixed lesion vertebrae that we derived using a machine learning approach. Results: The FE framework using global calibration strongly predicted the pathologic vertebrae stiffness (R 2 = 0.90, p < 0.0001) and strength (R 2 = 0.83, p = 0.0002) despite the remarkable variance in the pathologic bone structure and density. Specimen-specific calibration produced a near-perfect prediction of both stiffness and strength (R 2 = 0.99, p < 0.0001, for both), validating the FE approach. The FE damage-based simulations highlighted the differences in the pattern of spatial damage evolution between osteosclerotic and osteolytic vertebral bodies. Discussion: With failure, the FE simulation suggested a common damage evolution pathway progressing largely localized to the low bone modulus regions within the vertebral volume. Applying this FE approach may allow us to predict the onset and anatomical location of vertebral failure, which is critical for developing image-based diagnostics of impending pathologic vertebral fractures.