Mass-Like Fat at the Medial Midfoot: A Common Pseudolesion

Background Fatty masses are common and may be encountered in the foot and ankle. In some cases, normal subcutaneous fat may be mistaken for a discrete mass. Aims The aim of this study was to evaluate the common finding of prominent subcutaneous fat at the medial midfoot resembling a lipoma and to determine the prevalence of this pseudolesion by applying a series of potential size cutoff criteria. Materials and Methods Three musculoskeletal radiologists retrospectively evaluated 91 sequentially performed magnetic resonance imaging examinations of the ankle to measure fat resembling a discrete lipoma at the medial midfoot. Each blinded reader measured the largest area of continuous subcutaneous fat in orthogonal axial, coronal craniocaudal, and coronal transverse dimensions. Patient age, sex, and study indications were also recorded. Statistical analysis was performed with R and SAS 9.4 software Results A discrete fatty pseudolesion as defined by measuring at least 1 cm in all planes by measurements of at least two of three readers was present in 87% of cases (79 of 91). When a size criterion of 1.5 cm was used, a pseudolesion was documented in 14% of cases (13 of 91). There was a significant correlation between larger pseudolesion size and female sex in the axial plane; however, there was no correlation in the coronal craniocaudal and coronal transverse dimensions. Conclusions Subcutaneous fat at the medial midfoot often has a mass-like appearance that could be mistaken for a lipoma. It is important to recognize this pseudolesion variant and not to confuse the imaging appearance for a discrete mass.

Performance of a Handheld Ultrasound Device to Assess Articular and Periarticular Pathologies in Patients with Inflammatory Arthritis

The purpose of this study was to assess the accuracy and performance of a new handheld ultrasound (HHUS) machine in comparison to a conventional cart-based sonographic machine in patients with inflammatory arthritis (IA). IA patients with at least one tender and swollen joint count were enrolled. US was performed on the clinically affected joints using a cart-based sonographic device (Samsung HS40) and a HHUS device (Butterfly iQ). One blinded reader scored all images for the presence of erosions, bony enlargement, synovial hypertrophy, joint effusion, bursitis, tenosynovitis, and enthesitis. Synovitis was graded (B mode and power Doppler (PD)) by the 4-level EULAR-OMERACT scale. To avoid bias by the blinded reader, we included 67 joints of two healthy volunteers in the evaluation. We calculated the overall concordance and the concordance by type of joint and pathological finding. We also measured the time required for the US examination per joint with both devices. Thirty-two patients (20 with RA, 10 with PsA, and one each with gout and SLE-associated arthritis) were included, and 186 joints were examined. The overall raw concordance in B mode was 97% (κappa 0.90, 95% CI (0.89, 0.94)). In B mode, no significant differences were found in relation to type of joint or pathological finding examined. The PD mode of the HHUS device did not detect any PD signal, whereas the cart-based device detected a PD signal in 61 joints (33%). The portable device did not offer any time savings compared to the cart-based device (47.0 versus 46.3 s). The HHUS device was accurate in the assessment of structural damage and inflammation in patients with IA, but only in the B mode. Significant improvements are still needed for HHUS to reliably demonstrate blood flow detection in PD mode.

Otitis Media Middle Ear Effusion Identification and Characterization Using an Optical Coherence Tomography Otoscope

Objective To determine the feasibility of detecting and differentiating middle ear effusions (MEEs) using an optical coherence tomography (OCT) otoscope. Study Design Cross-sectional study. Setting US tertiary care children’s hospital. Subjects and Methods Seventy pediatric patients undergoing tympanostomy tube placement were preoperatively imaged using an OCT otoscope. A blinded reader quiz was conducted using 24 readers from 4 groups of tiered medical expertise. The primary outcome assessed was reader ability to detect presence/absence of MEE. A secondary outcome assessed was reader ability to differentiate serous vs nonserous MEE. Results OCT image data sets were analyzed from 45 of 70 total subjects. Blinded reader analysis of an OCT data subset for detection of MEE resulted in 90.6% accuracy, 90.9% sensitivity, 90.2% specificity, and intra/interreader agreement of 92.9% and 87.1%, respectively. Differentiating MEE type, reader identification of nonserous MEE had 70.8% accuracy, 53.6% sensitivity, 80.1% specificity, and intra/interreader agreement of 82.9% and 75.1%, respectively. Multivariate analysis revealed that age was the strongest predictor of OCT quality. The mean age of subjects with quality OCT was 5.01 years (n = 45), compared to 2.54 years (n = 25) in the remaining subjects imaged ( P = .0028). The ability to capture quality images improved over time, from 50% to 69.4% over the study period. Conclusion OCT otoscopy shows promise for facilitating accurate MEE detection. The imageability with the prototype device was affected by age, with older children being easier to image, similar to current ear diagnostic technologies.

Value of Digital Breast Tomosynthesis versus Additional Views for the Assessment of Screen-Detected Abnormalities - a First Analysis

Background: The purpose of this study was to countercheck the equivalence of single-view digital breast tomosynthesis (DBT) or DBT with additional views (DBT+AV) compared to traditional standard assessment by additional views (AV) in patients with a screen-detected abnormality. Patients and Methods: Patients with a screen-detected abnormality were consecutively invited to obtain 1 single-view wide-angle DBT in addition to the indicated AV. The study was approved by the local ethics committee and by the Federal Office for Radiation Protection. Results: This study is based on 311 lesions in 285 patients with a follow-up of > 2 years and/or biopsy. Counting BI-RADS 0 and 3 as positive calls, the sensitivity/specificity of DBT+AV versus DBT only versus AV only were 96.4/54.3%, 96.4/56.6%, and 90.9/42.2%, respectively. The specificities and BI-RADS classifications differed significantly (p < 0.01). AV appeared unnecessary in 88.8% of the cases. Conclusion: DBT appeared to be at least equivalent to AV for assessing indeterminate screen-detected lesions and could replace AV for most lesions. To obtain the extra information appears possible without increasing the overall radiation dose. Subsequent blinded reader studies are ongoing.

Abstract 17600: Improved Iterative Reconstruction Reduces Artifacts and Results in Larger Measurements of Ileofemoral Artery Size on Computed Tomography in Patients Referred for Transcatheter Aortic Valve Replacement

Background: Computed tomography (CT) is typically used to measure ileofemoral artery size in patients considered for transcatheter aortic valve replacement (TAVR). However, these patients often have significant arterial calcification, which can introduce artifacts and limit measurement accuracy. We hypothesized that improved iterative reconstruction would improve image quality and reduce artifacts, resulting in larger measured size. Methods: We examined 56 patients undergoing CT for possible TAVR, and compared image quality and ileofemoral arterial size between separate reconstructions of the same studies, comparing standard (STD) advanced statistical iterative reconstruction and improved model-based iterative reconstruction (MBIR). A blinded reader identified the sites with the smallest luminal diameter, and provided identical short-axis reformats for both reconstructions. A separate blinded reader graded image quality and made measurements in a random sequence. We compared mean and minimal diameters, image quality (1 poor, 4 excellent), and signal and noise. Results: Mean age was 77 ± 10 years and 54% were male. Table 1 compares measured diameters and image quality between STD and MBIR reconstructions. Between STD and MBIR images, ≥moderate beam-hardening artifacts were observed in 30% (17/56) and 9% (5/56) of patients, respectively (p=0.008); severe artifacts were seen in 23% (13/56) and 5% (3/56) of patients, respectively (p=0.01). Overall image quality of STD and MBIR images was graded as good or excellent in 70% (39/56) and 91% (51/56) of cases, respectively (p=0.008). Conclusion: In patients referred for TAVR, improved iterative reconstruction resulted in higher image quality, fewer beam-hardening artifacts, and larger measurements of ileofemoral artery size.

Metric Properties of the SPARCC Score of the Sacroiliac Joints — Data from Baseline, 3-month, and 12-month Followup in the SPACE Cohort

Objective.To evaluate metric properties of the SpondyloArthritis Research Consortium of Canada (SPARCC) score of the sacroiliac (SI) joints.Methods.Patients with back pain (≥ 3 months, ≤ 2 years, onset < 45 years) were included in the SPACE cohort (SpondyloArthritis Caught Early). Patients with (possible) axial spondyloarthritis had followup visits after 3 and 12 months and were treated according to clinical practice. Magnetic resonance imaging (MRI) of the SI joints (MRI-SI) was scored in 2 independent campaigns (campaign 1: at baseline and 3 months; campaign 2: at baseline, 3 months, and 12 months) by 2 different blinded reader pairs, applying the Assessment of Spondyloarthritis International Society (ASAS) definition (MRI-SI+ vs MRI-SI−; discordant cases were adjudicated by a third reader) and SPARCC score (mean of 2 agreeing readers). Calculations were made for agreement between SPARCC score cutoff values and a consensus judgment of MRI-SI+ (ASAS definition) as external standard, change in SPARCC score, and smallest detectable changes (SDC) over 3 and 12 months.Results.SPARCC score ≥ 2 showed best agreement with MRI-SI+ in both campaigns. Regarding observed changes in relation to SDC, SPARCC score changed in 70/151 patients; 26/70 patients changed > SDC (3.4), of whom 20 patients received stable treatment over 3 months in campaign 1. Over 3 months, 20/68 patients showed changes in SPARCC score; 11/20 > SDC (2.1), of whom 8 patients received stable treatment. Over 1 year, 23/74 patients changed their SPARCC score; 14/23 changed > SDC (2.4), of whom 7 received stable treatment in campaign 2.Conclusion.SPARCC score ≥ 2 can be used as surrogate for a consensus judgment of MRI-SI+ (ASAS definition) in clinical trials. The SDC ranged from 2.1–3.4 dependent on reader pair and were close to the proposed minimum important change of 2.5.

Abstract WMP9: Impact of Collateral Blood Flow on Clinical Presentation, Diffusion and Perfusion Imaging, Infarct Growth and Clinical Outcome in the DEFUSE 2 Trial

Objective: To determine the relationships between angiographic collaterals and diffusion/perfusion imaging, subsequent infarct growth and clinical outcomes in DEFUSE 2 study patients. Methods: Patients undergoing endovascular therapy within 12 hours of stroke onset were prospectively enrolled. Only patients with a TICI score of 0, 1 and ICA/M1 occlusion at baseline were included in this analysis. A blinded reader assigned a collateral score using a previously described 5 point scale, from 0 (no collateral flow) to 4 (complete/rapid collaterals to entire ischemic territory). Analysis was dichotomized to poor flow (0-2) versus good flow (3-4). Collateral score was correlated with baseline NIHSS, DWI volume, PWI volume (Tmax > 6), TICI reperfusion, infarct growth and mRS at day 90. Results: Sixty patients had TICI 0, 1 ICA/M1 occlusions and adequate angiographic images to evaluate collaterals. Baseline NIHSS correlated with collateral score (p=0.002). Median NIHSS for patients with poor collateral flow (0-2) was 18 (IQR, 13-22) versus 14 (10-17) for those with good flow (3-4), p=0.025. Baseline T max > 6 volume correlated with collateral score (p=0.002). Median volume of tissue at risk (T max > 6) in those with poor collateral flow was 115 ml (IQR, 74-136) versus 82 (51-109) with good flow, p=0.012. Collateral score did not correlate with baseline DWI volume. TICI reperfusion (0-3) correlated with collateral score (p=0.027). Patients with poor collateral flow had 29% TICI 2b-3 reperfusion versus 65.5% with good flow, p=0.009. Those with poor reperfusion (TICI 0-2a) showed a trend to more infarct growth with poor collaterals, 92 ml (52-194) [mean (IQR)] versus 36 ml (14-106) with good collaterals, p=0.06. Patients with poor collaterals who reperfused (TICI 2b-3) were still likely to have a mRS 0-2 at 90 days compared to those without reperfusion; OR 12 (95% CI, 1.6-98). Conclusion: Collaterals correlate with baseline clinical stroke severity and the PWI volume. In addition, good collaterals correlate with higher rates of reperfusion (TICI 2b-3). When patients do not reperfuse, good collaterals appear to limit infarct growth.