Magnetic resonance imaging of femoral nerve injury in the setting of anterior approach total hip arthroplasty.

PURPOSE: To illustrate MRI findings in patients with femoral neuropathy following anterior approach total hip arthroplasty (THA). METHODS: This was a retrospective review of patients who underwent MRI for femoral neuropathy following anterior approach THA between January 1, 2010, and July 1, 2022. Included patients had no preexisting neurologic condition. Clinical and diagnostic data were collected. MRIs were reviewed in consensus by 2 musculoskeletal radiologists. RESULTS: A total of 115 patient records were reviewed, 17 of which were included in the final analysis (mean age 64 years; 11 females). Study subjects presented with weakness with hip flexion and knee extension and pain and numbness in the femoral nerve distribution. In 7 subjects, the femoral nerve appeared normal. In 5 subjects, the femoral nerve was hyperintense on fluid-sensitive fat-suppressed imaging. In 4 patients, mass effect on the femoral nerve by either ill-defined soft tissue edema (n = 2), seroma (n = 1), or heterotopic ossification (n = 1) was detected. Only 1 patient had a nerve transection. Patients were imaged at a median time of 8 months (range: 1 day to 11 years) following arthroplasty placement. Clinical follow-up was available in 8 patients, of whom half had complete symptomatic resolution and half had partial improvement at a mean follow-up time of 39.3 months (SD 51.1). Of these 8, 1 underwent revision arthroplasty, 1 had removal of hardware, and another had excision of heterotopic ossification. CONCLUSION: MRI provides a means to directly evaluate the femoral nerve following anterior approach THA in both the immediate and chronic postoperative periods.

When to lavage in the absence of a sonographically visible joint effusion in painful total knee arthroplasty: a retrospective longitudinal study.

OBJECTIVE: To determine if knee arthroplasty without sonographically visible effusion needs to undergo lavage to rule out infection. METHODS: Patients were accrued by a retrospective search of a longitudinally maintained radiology database looking for patients referred for ultrasound guided aspiration of suspected TKA infection. Clinical presentations, laboratory tests, intraoperative findings, and follow-up were reviewed. RESULTS: Four hundred sixty-nine patients were included (mean age of 67 years (range, 36-91)) including 251 females. Four hundred three patients had effusions, of which 57 were infected based on ultrasound-guided and surgical aspirates. Sixty-four patients lacked effusions, of which 47 underwent lavage at the clinicians' request, with 6/47 infected. Nineteen patients without effusion were not lavaged at the clinicians' request due to low suspicion, and none were infected. Patients with positive lavage cultures all had clinical risk factors. Infection rates were significantly higher in patients with joint effusion and clinical suspicion for infection compared to absent joint effusion and absent clinical suspicion. A significantly higher proportion of patients with hyperemia or moderate-severe synovial thickening on ultrasound were symptomatic and had joint effusion and positive joint cultures. Aspiration of native fluid had 85% sensitivity and 100% specificity while lavage had a sensitivity of 57% and specificity of 100%. Negative predictive value for native aspirates was 94% compared to 86% for lavage. CONCLUSION: A TKA with low clinical suspicion of infection does not need to undergo lavage in the absence of a sonographically visible effusion.

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.

Imaging of total hip arthroplasty: Part I - Implant design, imaging techniques, and imaging of component wear and fracture.

Despite being one of the most reliable procedures in orthopedic surgery, complications can occur after total hip arthroplasty, and radiology plays an essential role in their evaluation. This article will review the various types of hip arthroplasty and their normal appearances on imaging, followed by mechanisms and imaging appearances of component wear and fracture.

Imaging of total hip arthroplasty: part II - imaging of component dislocation, loosening, infection, and soft tissue injury.

Despite the remarkable success of total hip arthroplasty as treatment of arthritis of the hip, complications can still occur, and imaging plays a crucial role for both diagnosis and guiding management. Component dislocation in total hip arthroplasty is usually diagnosed on radiographs, but cross-sectional imaging is necessary to quantitatively assess component orientation which may have predisposed to the dislocation. The definitive sign of component loosening on radiography is progressive motion of the component, but CT will provide more osseous detail and recent studies have shown the role of MRI in assessing component loosening as well. Infection is a devastating complication for which early diagnosis is crucial. Radiographs are not sensitive for infection, but there are certain MRI features that can suggest infection, and ultrasound and fluoroscopy are useful for guiding arthrocenteses to diagnose infection. Tendon and neurovascular injuries can be a source of long-term disability after total hip arthroplasty, and radiological studies, particularly advanced cross-sectional imaging such as MRI and ultrasound, often play an important role in their diagnoses.

Automatic Assessment Of Hip Effusion From MRI.

Joint effusion is a hallmark of osteoarthritis (OA) associated with stiffness, and may relate to pain, disability, and long-term outcomes. However, it is difficult to quantify accurately. We propose a new Deep Learning (DL) approach for automatic effusion assessment from Magnetic Resonance Imaging (MRI) using volumetric quantification measures (VQM). We developed a new multiplane ensemble convolutional neural network (CNN) approach for 1) localizing bony anatomy and 2) detecting effusion regions. CNNs were trained on femoral head and effusion regions manually segmented from 3856 images (63 patients). Upon validation on a non-overlapping set of 2040 images (34 patients) DL showed high agreement with ground-truth in terms of Dice score (0.85), sensitivity (0.86) and precision (0.83). Agreement of VQM per-patient was high for DL vs experts in term of Intraclass correlation coefficient (ICC)= 0.88[0.80,0.93]. We expect this technique to reduce inter-observer variability in effusion assessment, reducing expert time and potentially improving the quality of OA care.Clinical Relevance- Our technique for automatic assessment of hip MRI can be used for volumetric measurement of effusion. We expect this to reduce variability in OA biomarker assessment and provide more reliable indicators for disease progression.

Volumetric quantitative measurement of hip effusions by manual versus automated artificial intelligence techniques: An OMERACT preliminary validation study.

OBJECTIVE: Preliminary assessment, via OMERACT filter, of manual and automated MRI hip effusion Volumetric Quantitative Measurement (VQM). METHODS: For 358 hips (93 osteoarthritis subjects, bilateral, 2 time points), 2 radiologists performed manual VQM using custom Matlab software. A Mask R-CNN artificial-intelligence (AI) tool was trained to automatically compute joint fluid volumes. RESULTS: Manual VQM had excellent inter-observer reliability (ICC 0.96). AI predicted hip fluid volumes with ICC 0.86 (status), 0.58 (change) vs. 2 human readers. CONCLUSION: Hip joint fluid volumes are reliably assessed by VQM. It is feasible to automate this approach using AI, with promising initial reliability.

Evaluation of Thyroid Ultrasound Report Quality and Assessing Effect of Adherence to Risk Stratification Criteria on Referral for Thyroid Nodule Biopsy.

PURPOSE: This study aims to evaluate the quality of diagnostic thyroid ultrasound reports and determine the impact of consistent adherence to 2015 American Thyroid Association (ATA) and 2017 American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) on reducing unnecessary referrals for thyroid nodule biopsy. MATERIALS AND METHODS: Reports from 291 referrals for thyroid nodule biopsy were included for retrospective report evaluation (males: 42; mean age: 56) according to 2015 ATA and ACR TI-RADS lexicon. Cytology results were collected for each patient. Two radiologists blinded to cytology results independently, retrospectively reviewed imaging of the referrals, and rescored them according to 2015 ATA and 2017 ACR TI-RADS risk stratification systems. Statistical analysis was completed using chi-square analysis and calculation of κ statistic for interobserver variability. RESULTS: No report completely addressed all features associated with malignancy. Over half of the reports did not include descriptors on echogenicity, shape, margin, or echogenic foci. In all, 9.3% of biopsies showed malignant histology. Rescoring of referrals demonstrated decrease in biopsy referrals by 55% as per 2017 ACR TI-RADS and 14% as per 2015 ATA (P < .0001). There was no impact on detection of malignancy with adherence to ATA or ACR criteria and less interobserver variability with application of 2017 ACR TI-RADS compared to 2015 ATA. CONCLUSION: Thyroid ultrasound report quality was found variable with respect to nodule description. Reports recommended biopsy based on nodule size with no detailed description of other imaging features. Adherence to risk stratification system would have resulted in significant reduction in the number of unnecessary biopsy referrals.

Development of a technique for MRI gold-standard direct volumetric measurement of complex joint effusion, and validation at the hip.

OBJECTIVE: Accurate joint fluid quantification on MRI cannot simply rely on measuring the maximum fluid depth or using an ellipsoid approximation as this does not fully characterize the complex shape of a fluid-filled joint. As per the Outcome Measurement in Rheumatology (OMERACT) filter, we sought to evaluate the feasibility, reliability, and validity of a semi-automated supervised technique to quantify hip effusion volume. MATERIALS AND METHODS: Ninety-three hip osteoarthritis patients were imaged with coronal short TI inversion recovery (STIR) and sagittal intermediate weighted fat-suppressed (IWFS) sequences at two time points (Fig. 1). Volumetric quantitative measurement (VQM) of joint fluid and measurement of the largest femoral neck fluid thickness (FTM) was performed using the custom MATLAB software. Self-reported Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and clinical measures of pain, stiffness, and function were recorded. RESULTS: Inter-observer reliability was significantly higher for VQM than FTM (ICC = 0.96 vs. 0.85, p < 0.05). VQM and FTM correlated moderately (r = 0.76, p < 0.0001). There was significantly more articular fluid in symptomatic than asymptomatic hips at baseline (mean = 9.8 vs. 5.9 mL). Volumetric quantitative measurement generally displayed more frequent and stronger correlations to clinical parameters than FTM. Volumetric quantitative measurement required 3.9 min/hip vs. < 1 min/hip for femoral neck fluid thickness. CONCLUSION: Volumetric quantitative measurement of joint effusion can serve as an MRI gold-standard, could apply to other joints and collections, and is highly suited to future automation.

Normal hip joint fluid volumes in healthy children of different ages, based on MRI volumetric quantitative measurement.

BACKGROUND: While magnetic resonance imaging (MRI) of the pelvis and hips is common in pediatric patients, to date there are no data on the quantification of normal hip joint fluid volume in this patient population. OBJECTIVE: We sought to assess the feasibility and reliability of quantitative hip joint fluid measurement in the pediatric population to estimate the normal volume of fluid in a pediatric hip joint. MATERIALS AND METHODS: Seventy healthy children ages 8-17 years underwent a pelvic MRI including a large field of view coronal T2 fat-saturated sequence where hips were entirely imaged. Following 3 training sessions, 2 readers with experience in musculoskeletal imaging performed volumetric quantitative measurements of hip fluid (140 hips) using semiautomated pixel-based thresholding on custom MATLAB software. RESULTS: The mean processing time per hip was 2 min, 41 s. The mean volume of fluid in a hip joint was 2.1 mL (range: 0.38-5.41 mL), increasing slightly with age. Volumes were also greater in boys than in girls (P=0.004). Intra-observer and interobserver agreement were high (intra-class correlation coefficients 0.93 and 0.98, respectively), with mean volume differences of 0.04 mL for intra-observer and 0.09 mL for interobserver. CONCLUSION: A semiautomated pixel-based thresholding approach was feasible and reliable for measuring joint fluid in pediatric hip MRI. The average fluid volume of 2.1 mL can represent a visually substantial quantity of fluid per MRI slice, particularly in small children, and should not be misinterpreted as a joint effusion.

Long-term outcomes of thrombotic microangiopathy treated with plasma exchange: A systematic review.

With the adoption of plasma exchange as standard treatment for thrombotic microangiopathy (TMA), more patients are surviving and long-term outcomes have greater relevance. We conducted a systematic review to synthesize and evaluate the quality of evidence on long-term outcomes of TMA among adults treated with plasma exchange and to identify factors that may be associated with a worse long-term prognosis. We searched databases from 1980 to 2013 for eligible articles published in any language. We included studies that reported outcomes in at least ten adults with a history of TMA treated with plasma exchange and at least 6 months of follow-up. We abstracted data in duplicate and assessed the methodological quality of each study using an assessment tool developed based on recommended validity criteria. We screened 6672 articles, reviewed 213, and included 34 studies totaling 1182 patients (study median [range], 24 [10-118]). The mean (or median) follow-up ranged from 6 months to 13 years. The cumulative incidence of relapse and mortality was highly variable and ranged from 3 to 84 and 0 to 61%, respectively. The incidence of other outcomes across 10 studies also varied (outcomes included hypertension, kidney disease, preeclampsia, stroke, seizure, severe cognitive impairment, and depression); in three other studies, long-term neurocognitive function and health-related quality of life were significantly lower than in the general population. Patients who survive an episode of TMA may be susceptible to long-term vascular complications, but the magnitude of this risk and how to mitigate it remains unclear. Am. J. Hematol. 91:623-630, 2016. © 2016 Wiley Periodicals, Inc.