Fellowship-trained Radiologists Research Articles

Prevalence of femoral condyle injuries in the setting of tibial plateau fractures

BackgroundTibial plateau fracture patterns are influenced by the direction and energy of the impact, and the bone quality. Associated articular femoral injuries can result from the same impact but are insufficiently studied. This study quantifies the prevalence of three distinct articular femoral condyle injuries: (1) impaction fractures, (2) contusions, and (3) condyle fractures. For impaction fractures we assessed the depth, width, length, and surface area. MethodsWe retrospectively reviewed patients who had undergone surgery for a tibial plateau fracture in a tertiary trauma center. Two fellowship-trained radiologists analyzed preoperative CT scans for associated femoral condyle injuries. We defined (1) impaction fractures (depressions ≥ 1.5 mm) with a sclerotic band, a fracture line, or both; (2) contusions (depressions < 1.5 mm) with a sclerotic band; and (3) condyle fractures as sub- or osteochondral fractures. ResultsWe identified 149 patients (62 male) with a tibial plateau fracture with a CT scan available. The overall prevalence of articular femoral condyle injuries was 26% (n = 39). The prevalence of impaction fractures was 9.4% (n = 14), of contusions 14% (n = 21), and of condylar fractures 3.0% (n = 4). Factors associated with a higher prevalence of femoral condyle injury were younger age (p = 0.029), male sex (p = 0.014), and absence of comorbidity (p = 0.005). The mean depth of impaction fractures was 2.3 mm (SD: 0.78; range 1.6 to 4). ConclusionConcomitant articular femoral condyle injuries occur in one out of four patients with a tibial plateau fracture. Although most femoral injuries were subtle, and none underwent surgical treatment, they might harbor information regarding the likelihood of future joint degeneration and knee instability.Level of evidence: IV.

Castellvi classification of lumbosacral transitional vertebrae: comparison between conventional radiography, CT, and MRI.

The reliability and diagnostic accuracy of commonly used diagnostic imaging modalities in the classification of lumbosacral transitional vertebrae (LSTV) are poorly known, and comparative studies are scarce. To compare the diagnostic performance of conventional radiography (CR), computed tomography (CT), and magnetic resonance imaging (MRI) in classifying LSTVs. In this retrospective cross-sectional study, a total of 852 patients undergoing lumbar imaging studies using all three modalities were initially assessed for the presence of LSTV using CT scans. In total, 100 patients with LSTV anatomy were identified. Four readers performed blinded and independent evaluations of these 100 patients on each modality, and an experienced fellowship-trained radiologist performed a gold standard read using all three modalities. Inter-reader reliability metrics were analyzed in comparison to the gold standard. Statistical software R (4.2.1) was used for the analyses. We found superior diagnostic efficacy for CT: the sensitivity, specificity, accuracy, and balanced accuracy were 76%, 93%, 77%, and 84%, respectively. For MRI, the metrics were 54%, 88%, 56%, and 68%, and for CR 32%, 85%, 42%, and 59%, respectively. Inter-reader reliability was found to be good for CT (κ = 0.63-0.71) and fair for both CR (κ = 0.16-0.32) and MRI (κ = 0.24-0.56). CT had the highest diagnostic performance in all measured metrics with good inter-reader reliability. MRI and CR showed fairly poor sensitivity and accuracy, and thus consideration should be used when classifying LSTVs with these two modalities.

Micro-enema immediately prior to prostate MRI: effects on rectal gas, image quality and PI-QUAL score.

Our aim was to determine whether the administration of a micro-enema immediately prior to prostate MRI is associated with a reduction in rectal gas, gas related artifacts and an improvement in image quality and PI-QUAL score. This retrospective analysis enrolled 171 patients who underwent multiparametric 3T prostate MRI at our institution between January 2021 and September 2022. 86 patients received a micro-enema, and a further 85 patients did not. Two fellowship trained abdominal radiologists were blinded and independently reviewed each prostate MRI, recording scores on a dedicated scoring sheet. The quality of T2 weighted (T2W), diffusion weighted (DWI), and dynamic contrast enhancement (DCE) images were assessed according to standardised scales supported in the literature. In addition, gas related artifacts and rectal gas level were examined. An independent-samples Mann-Whitney U and t-test were performed, comparing both the median and mean score between micro-enema and no micro-enema groups for each reader. Spearman's correlation was used to determine the strength of relationship between variables. A quadratic weighted Cohen's Kappa and percent agreement were used to assess inter-observer agreement. Image quality was improved in those who received the micro-enema compared to those who did not according to the visual grading scale on the DWI sequence for both readers (reader 1: median 4 vs. 4, p < 0.001, mean 4.27 vs. 3.92, p < 0.001; reader 2: median 5 vs. 4, p < 0.001, mean 4.74 vs. 4.14, p < 0.001). PI-QUAL score was significantly improved in the micro-enema group for reader 2 only (reader 1: median 4 vs. 4, p = 0.25, mean 3.99 vs. 4.08, p = 0.21; reader 2: median 5 vs. 5, p = 0.01, mean 4.95 vs. 4.78, p = 0.01). Visual grading score for both the T2W and DCE images was not significantly different. Rectal gas level was lower in patients who received the micro-enema for both readers (reader 1: median 2 vs. 4, p < 0.001, mean 2.12 vs. 3.60, p < 0.001; reader 2: median 1 vs. 2, p < 0.001, mean 1.37 vs. 2.48, p < 0.001), correlating with a lower score for gas-related artifacts (reader 1: median 1 vs. 2, p < 0.001, mean 1.50 vs. 1.92, p < 0.001; reader 2: median 1 vs. 1, p < 0.001, mean 1.16 vs. 1.71, p < 0.001) in this group. Correlation between rectal gas level and gas-related artifacts on DWI regardless of whether a micro-enema was given was strong (rs = 0.71, p < 0.001). Correlation was moderate to strong between rectal gas level and image quality on DWI (rs = -0.63, p < 0.001). There was only 1 (1.2%) borderline diagnostic or non-diagnostic DWI sequence in those who received the micro-enema, compared to 9 (10.6%) in those who did not (p = 0.009). Interobserver agreement was moderate for image quality on DWI, gas related artifacts and rectal gas level (weighted kappa values of 0.52, 0.49 and 0.53 respectively). The administration of a micro-enema immediately prior to prostate MRI is associated with a significant improvement in image quality on the DWI sequence compared to no bowel preparation. This is mediated through a reduction in rectal gas and gas related artifacts. Improvements in PI-QUAL score was mixed between readers.

Poster 271: Improving Non-Invasive Diagnosis and Grading of Cartilage Defects in the Knee - Accuracy of Ultra High Field 7-Tesla MRI as Compared with Arthroscopy

Objectives: Osteoarthritis (OA) is a joint disease characterized by degradation of articular cartilage and subchondral bone. Cartilage injury plays an important role in the pathogenesis of osteoarthritis, and disease modifying treatments aiming to preserve and possibly regenerate cartilage are an area of active interest. Early diagnosis is crucial, as the disease may be more responsive to treatment at an early stage, and there is a critical unmet need for improved non-invasive morphologic cartilage imaging techniques. Standard clinical MRI is performed on a 1.5T or 3T machine. Ultra-high field (UHF) 7-Tesla (7T) magnetic resonance imaging (MRI) is a new technology that offers 2.3x improved signal-to noise ratio (SNR) compared to 3T MRI and 2.8x SNR compared to 1.5T MRI. The purpose of this study was to estimate the accuracy of 7T MRI for the detection and grading of cartilage lesions in the knee. The hypothesis was that 7T images would offer better detection and more accurate grading of chondral lesions than standard clinical grade MRI scans. Methods: In this prospective, paired, blinded study, patients who had undergone a 1.5 or 3T standard of care (SOC) MRI and were scheduled for knee arthroscopy were enrolled (10/2019 to 08/2021) and a study intervention 7T MRI was performed prior to surgery. The study was approved by our institutional review board, and it was funded by the Methodist-Siemens Collaboration. Exclusion criteria included contraindication to MRI (e.g., pacemaker), weight less than 30 kg, and pregnancy. Scans were reviewed by three independent fellowship-trained radiologists who were blinded to clinical and arthroscopic data. Scans were reviewed over 5 days, with a 4 week “washout” period between review of SOC and 7T scans to limit recall bias. Readers were blinded to clinical and arthroscopic data and graded all six articular surfaces of the knee (patella, trochlea, lateral condyle, medial condyle, lateral tibia, medial tibia) using a modified Outerbridge classification system. At the time of arthroscopy, each articular surface was graded by the operating surgeon according to a modified Outerbridge system similar to above, with the exception that Grade 1 = softening of the articular cartilage. The surgeon was blinded to 7T images at the time of arthroscopy, although they had access to the SOC MRI, which was necessary for patient care. Using arthroscopy as the gold standard, we calculated sensitivity and specificity of SOC MRI and 7T MRI. An Outerbridge grade of 0 was classified as negative, while a grade of 1-4 was classified as positive. A secondary analysis of sensitivity and specificity was performed on a per articular surface basis, with 6 articular surfaces per patient after correction for within subject clustered data. A Mann-Whitney U test was used to compare diagnostic scores and ratings between instruments (SOC vs. 7T). Coefficients of variation between observers within each instrument were compared for each variable using a paired sample t-test. Type-I error was set at alpha=0.05 Results: A total of 100 patients (age: 43 ± 14, 54 female, 46 male) were enrolled. 7T MRI resulted in improved sharpness (defined by visibility of nerve fascicles) and shading (based on artifacts) compared to SOC MRI (Figure 1, p &lt; 0.001 for both). There was improved contrast between fluid and cartilage with 7T MRI (using confidence rating at axial mid-patella, p = 0.003). 7T MRI had a higher sensitivity in detecting cartilage lesions for five of the six articular surfaces when using the arthroscopic gold standard, but with lower specificity for all surfaces (Figure 2). Finally, there was improved inter-observer reliability in detecting and grading cartilage defects with 7T compared to SOC MRI (p &lt; 0.05). Conclusion: Based on our findings thus far, 7T MRI appears to result in improved measurement ratings, sensitivity, and inter-observer reliability compared to SOC in detecting cartilage lesions in the knee. Further work is needed to evaluate cost effectiveness of 7T MRI.

Is staging breast magnetic resonance imaging for invasive lobular carcinoma worthwhile?

Invasive lobular carcinoma (ILC) is challenging to stage accurately using mammography (MG) and ultrasound (US) with undiagnosed ipsilateral and contralateral cancer resulting in poor patient outcomes including return to surgery. Our institution employs routine staging breast MRI in ILC for this reason. However, increased time for further imaging/biopsies contributes to patient anxiety and potentially delays definite management. We aimed to quantify the frequency of staging MRI-detected additional lesions requiring biopsy or follow-up, the added cancer detection rate and MRI prompted change in surgical management. An observational study on staging breast MRI for newly diagnosed ILC at a tertiary Western Australian hospital from January 2019 to August 2022. Standardized 3T MRI protocol was performed, double read by unblinded fellowship-trained radiologists. Histopathology from biopsy, surgery, or first annual surveillance was the reference standard for additional MRI-detected lesions. One hundred ten MRI studies demonstrated 49 (45%) patients had at least one additional clinically significant MRI-detected lesion. Thirty-one patients had an additional ipsilateral lesion detected, of which 18 (58%) proved malignant; 14 (45%) multifocal and 4 (13%) multicentric ILC. Additional work-up of MRI-detected lesions averaged a 9-day delay to definitive surgery compared to patients with a negative or definitively benign MRI. MRI changed surgical planning in 11 of 110 cases from breast conservation surgery (BCS) to mastectomy and there were two contralateral cancers diagnosed. BCS reoperation rate was 11%. Staging MRI for ILC identifies clinically significant lesions in nearly half of patients, predominantly ipsilateral multifocal disease, without significant delay to definitive surgery.

An evaluation of AI generated literature reviews in musculoskeletal radiology

PurposeThe use of artificial intelligence (AI) tools to aid in summarizing information in medicine and research has recently garnered a huge amount of interest. While tools such as ChatGPT produce convincing and naturally sounding output, the answers are sometimes incorrect. Some of these drawbacks, it is hoped, can be avoided by using programmes trained for a more specific scope. In this study we compared the performance of a new AI tool (the-literature.com) to the latest version OpenAI's ChatGPT (GPT-4) in summarizing topics that the authors have significantly contributed to. MethodsThe AI tools were asked to produce a literature review on 7 topics. These were selected based on the research topics that the authors were intimately familiar with and have contributed to through their own publications. The output produced by the AI tools were graded on a 1–5 Likert scale for accuracy, comprehensiveness, and relevance by two fellowship trained consultant radiologists. ResultsThe-literature.com produced 3 excellent summaries, 3 very poor summaries not relevant to the prompt, and one summary, which was relevant but did not include all relevant papers. All of the summaries produced by GPT-4 were relevant, but fewer relevant papers were identified. The average Likert rating was for the-literature was 2.88 and 3.86 for GPT-4. There was good agreement between the ratings of both radiologists (ICC = 0.883). ConclusionSummaries produced by AI in its current state require careful human validation. GPT-4 on average provides higher quality summaries. Neither tool can reliably identify all relevant publications.

Diagnosing periprosthetic hip joint infection with new-generation 0.55 T MRI

PurposeTo assess the accuracy of 0.55 T MRI in diagnosing periprosthetic joint infection (PJI) in patients with symptomatic total hip arthroplasty (THA). Material and methods0.55 T MRI of patients with THA PJI (Group A) and noninfected THA (Group B), including aseptic loosening (Group C, subgroup of B) performed between May 2021 and July 2023 were analysed retrospectively.Two musculoskeletal fellowship-trained radiologists independently identified MRI bone and soft tissue changes including: marrow oedema, periosteal reaction, osteolysis, joint effusion, capsule oedema and thickening, fluid collections, muscle oedema, bursitis, inguinal adenopathy, and muscle tears. The diagnostic performance of MRI discriminators of PJI was evaluated using Fisher’s exact test (p < 0.05) and interrater reliability was determined. 61 MRI scans from 60 THA patients (34 female, median age 68, range 41–93 years) in Group A (n = 9; female 4; median age 69, range 56–82 years), B (n = 51; 30; 67.5, 41–93 years), and C (10; 6; 67; 41–82 years) were included. ResultsCapsule oedema (sensitivity 89 %, specificity 92 %,), intramuscular oedema (89 %, 82 %) and joint effusion (89 %, 73 %) were the best performing discriminators for PJI diagnosis (p ≤ 0.001), when viewed individually and had combined 70 % sensitivity and 100 % specificity for PJI diagnosis in parallel testing. For the differentiation between PJI and aseptic loosening, intramuscular oedema (89 %, 80 %) and capsule oedema (89 %, 80 %) were significant discriminators (p ≤ 0.001) with combined 64 % sensitivity and 96 % specificity for PJI. ConclusionsNew generation 0.55 T MRI may aid in the detection of PJI in symptomatic patients. Oedema of the joint capsule, adjacent muscles as well as joint effusion were indicative of the presence of PJI.

Artificial Intelligence for Quantifying Cumulative Small Bowel Disease Severity on CT-Enterography in Crohn's Disease.

Assessing the cumulative degree of bowel injury in ileal Crohn's disease (CD) is difficult. We aimed to develop machine learning (ML) methodologies for automated estimation of cumulative ileal injury on computed tomography-enterography (CTE) to help predict future bowel surgery. Adults with ileal CD using biologic therapy at a tertiary care center underwent ML analysis of CTE scans. Two fellowship-trained radiologists graded bowel injury severity at granular spatial increments along the ileum (1 cm), called mini-segments. ML segmentation methods were trained on radiologist grading with predicted severity and then spatially mapped to the ileum. Cumulative injury was calculated as the sum (S-CIDSS) and mean of severity grades along the ileum. Multivariate models of future small bowel resection were compared with cumulative ileum injury metrics and traditional bowel measures, adjusting for laboratory values, medications, and prior surgery at the time of CTE. In 229 CTE scans, 8,424 mini-segments underwent analysis. Agreement between ML and radiologists injury grading was strong (κ = 0.80, 95% confidence interval 0.79-0.81) and similar to inter-radiologist agreement (κ = 0.87, 95% confidence interval 0.85-0.88). S-CIDSS (46.6 vs 30.4, P = 0.0007) and mean cumulative injury grade scores (1.80 vs 1.42, P < 0.0001) were greater in CD biologic users that went to future surgery. Models using cumulative spatial metrics (area under the curve = 0.76) outperformed models using conventional bowel measures, laboratory values, and medical history (area under the curve = 0.62) for predicting future surgery in biologic users. Automated cumulative ileal injury scores show promise for improving prediction of outcomes in small bowel CD. Beyond replicating expert judgment, spatial enterography analysis can augment the personalization of bowel assessment in CD.

Validating the diagnostic accuracy of an MRI-based scoring system for differentiating benign uterine leiomyomas from leiomyosarcomas

ObjectiveUterine leiomyomas are the most common benign uterine tumors. They are difficult to distinguish from their malignant counterparts—smooth muscle tumors of unknown malignant potential (STUMP) and leiomyosarcoma. The purpose of...

Qualitative and quantitative spermatic cord abnormalities at CT predict symptomatic scrotal pathology

PurposeTo evaluate quantitative and qualitative spermatic cord CT abnormalities and presence of unilateral or bilateral symptomatic scrotal pathology (SSP) at ultrasound.MethodsThis retrospective study included 122 male patients (mean age 47.8 years) undergoing scrotal ultrasound within 24 h of contrast-enhanced CT (n = 85), non-contrast CT (NECT, n = 32) or CT-Urogram (n = 5). CECT quantitative analysis assessed differential cord enhancement using maximum Hounsfield unit measurements. Three fellowship trained body radiologists independently assessed qualitative cord abnormalities for both CECT and NECT. Qualitative and quantitative findings were compared with the presence of SSP. Reader performance, interobserver agreement and reader confidence were assessed for NECT and CECT. Quantitative cutoff points were identified which maximized accuracy, specificity, negative predictive value, and other measures.ResultsSSP was present in 36/122 patients (29.5%). Positive cases were unilateral in 30 (83.3%) and bilateral in 6 (16.6%). At quantitative assessment, 25% differential cord enhancement had the highest diagnostic accuracy (88.9%), with 90.5% positive predictive value, 88.4% negative predictive value, 96.8% specificity, and 70.4% sensitivity. At qualitative evaluation, CECT reader performance was excellent (aggregate AUC = 0.86; P < .001); NECT was poorly discriminatory, although remained significant (aggregate AUC = 0.67; P = .002). Readers had significantly higher confidence levels with CECT (P < .001). Qualitative inter-observer agreement was high for both CECT and NECT (ICC = 0.981 and 0.963, respectively).ConclusionSimple quantitative assessment of differential cord enhancement is highly accurate and specific for SSP at CECT. Qualitative abnormalities at CECT and NECT are also both predictors of SSP, however, CECT significantly out-performs non-contrast exams.Graphical abstract

Development and validation of an artificial intelligence model to accurately predict spinopelvic parameters.

Achieving appropriate spinopelvic alignment has been shown to be associated with improved clinical symptoms. However, measurement of spinopelvic radiographic parameters is time-intensive and interobserver reliability is a concern. Automated measurement tools have the promise of rapid and consistent measurements, but existing tools are still limited to some degree by manual user-entry requirements. This study presents a novel artificial intelligence (AI) tool called SpinePose that automatically predicts spinopelvic parameters with high accuracy without the need for manual entry. SpinePose was trained and validated on 761 sagittal whole-spine radiographs to predict the sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), T1 pelvic angle (T1PA), and L1 pelvic angle (L1PA). A separate test set of 40 radiographs was labeled by four reviewers, including fellowship-trained spine surgeons and a fellowship-trained radiologist with neuroradiology subspecialty certification. Median errors relative to the most senior reviewer were calculated to determine model accuracy on test images. Intraclass correlation coefficients (ICCs) were used to assess interrater reliability. SpinePose exhibited the following median (interquartile range) parameter errors: SVA 2.2 mm (2.3 mm) (p = 0.93), PT 1.3° (1.2°) (p = 0.48), SS 1.7° (2.2°) (p = 0.64), PI 2.2° (2.1°) (p = 0.24), LL 2.6° (4.0°) (p = 0.89), T1PA 1.1° (0.9°) (p = 0.42), and L1PA 1.4° (1.6°) (p = 0.49). Model predictions also exhibited excellent reliability at all parameters (ICC 0.91-1.0). SpinePose accurately predicted spinopelvic parameters with excellent reliability comparable to that of fellowship-trained spine surgeons and neuroradiologists. Utilization of predictive AI tools in spinal imaging can substantially aid in patient selection and surgical planning.

Deep Learning to Differentiate Benign and Malignant Vertebral Fractures at Multidetector CT.

Background Differentiating between benign and malignant vertebral fractures poses diagnostic challenges. Purpose To investigate the reliability of CT-based deep learning models to differentiate between benign and malignant vertebral fractures. Materials and Methods CT scans acquired in patients with benign or malignant vertebral fractures from June 2005 to December 2022 at two university hospitals were retrospectively identified based on a composite reference standard that included histopathologic and radiologic information. An internal test set was randomly selected, and an external test set was obtained from an additional hospital. Models used a three-dimensional U-Net encoder-classifier architecture and applied data augmentation during training. Performance was evaluated using the area under the receiver operating characteristic curve (AUC) and compared with that of two residents and one fellowship-trained radiologist using the DeLong test. Results The training set included 381 patients (mean age, 69.9 years ± 11.4 [SD]; 193 male) with 1307 vertebrae (378 benign fractures, 447 malignant fractures, 482 malignant lesions). Internal and external test sets included 86 (mean age, 66.9 years ± 12; 45 male) and 65 (mean age, 68.8 years ± 12.5; 39 female) patients, respectively. The better-performing model of two training approaches achieved AUCs of 0.85 (95% CI: 0.77, 0.92) in the internal and 0.75 (95% CI: 0.64, 0.85) in the external test sets. Including an uncertainty category further improved performance to AUCs of 0.91 (95% CI: 0.83, 0.97) in the internal test set and 0.76 (95% CI: 0.64, 0.88) in the external test set. The AUC values of residents were lower than that of the best-performing model in the internal test set (AUC, 0.69 [95% CI: 0.59, 0.78] and 0.71 [95% CI: 0.61, 0.80]) and external test set (AUC, 0.70 [95% CI: 0.58, 0.80] and 0.71 [95% CI: 0.60, 0.82]), with significant differences only for the internal test set (P < .001). The AUCs of the fellowship-trained radiologist were similar to those of the best-performing model (internal test set, 0.86 [95% CI: 0.78, 0.93; P = .39]; external test set, 0.71 [95% CI: 0.60, 0.82; P = .46]). Conclusion Developed models showed a high discriminatory power to differentiate between benign and malignant vertebral fractures, surpassing or matching the performance of radiology residents and matching that of a fellowship-trained radiologist. © RSNA, 2024 See also the editorial by Booz and D'Angelo in this issue.

The kidney imaging surveillance scoring system (KISSS): using qualitative MRI features to predict growth rate of renal tumors in patients with von-Hippel Lindau (VHL) syndrome.

To determine the reliability of an MRI-based qualitative kidney imaging surveillance scoring system (KISSS) and assess which imaging features predict growth rate (GR) of renal tumors in patients with VHL. We identified 55 patients with VHL with 128 renal tumors who underwent intervention from 2015 to 2020 at the National Cancer Institute. All patients had 2 preoperative MRIs at least 3 months apart. Two fellowship-trained radiologists scored each tumor on location and MR-sequence-specific imaging parameters from the earlier MRI. Weighted kappa was used to determine the degree of agreement between radiologists for each parameter. GR was calculated as the difference in maximum tumor dimension over time (cm/year). Differences in mean growth rate (MGR) within categories of each imaging variable were assessed by ANOVA. Apart from tumor margin and renal sinus, reliability was at least moderate (K>0.40) for imaging parameters. Median initial tumor size was 2.1 cm, with average follow-up of 1.2 years. Tumor MGR was 0.42 cm/year. T2 hypointense, mixed/predominantly solid, and high restricted diffusion tumors grew faster. When comparing different combinations of these variables, the model with the lowest mean error among both radiologists utilized only solid/cystic and restricted diffusion features. We demonstrate a novel MR-based scoring system (KISSS) that has good precision with minimal training and can be applied to other qualitative radiology studies. A subset of imaging variables (T2 intensity; restricted diffusion; and solid/cystic) were independently associated with growth rate in VHL renal tumors, with the combination of the latter two most optimal. Additional validation, including in sporadic RCC population, is warranted.

Photon-Counting Computed Tomography Versus Energy-Integrating Dual-Energy Computed Tomography: Virtual Noncontrast Image Quality Comparison.

This study aimed to compare the image quality of portal venous phase-derived virtual noncontrast (VNC) images from photon-counting computed tomography (PCCT) with energy-integrating dual-energy computed tomography (EI-DECT) in the same patient using quantitative and qualitative analyses. Consecutive patients retrospectively identified with available portal venous phase-derived VNC images from both PCCT and EI-DECT were included. Patients without available VNC in picture archiving and communication system in PCCT or prior EI-DECT and non-portal venous phase acquisitions were excluded. Three fellowship-trained radiologists blinded to VNC source qualitatively assessed VNC images on a 5-point scale for overall image quality, image noise, small structure delineation, noise texture, artifacts, and degree of iodine removal. Quantitative assessment used region-of-interest measurements within the aorta at 4 standard locations, both psoas muscles, both renal cortices, spleen, retroperitoneal fat, and inferior vena cava. Attenuation (Hounsfield unit), quantitative noise (Hounsfield unit SD), contrast-to-noise ratio (CNR) (CNR vascular , CNR kidney , CNR spleen , CNR fat ), signal-to-noise ratio (SNR) (SNR vascular , SNR kidney , SNR spleen , SNR fat ), and radiation dose were compared between PCCT and EI-DECT with the Wilcoxon signed rank test. A P < 0.05 indicated statistical significance. A total of 74 patients (27 men; mean ± SD age, 63 ± 13 years) were included. Computed tomography dose index volumes for PCCT and EI-DECT were 9.2 ± 3.5 mGy and 9.4 ± 9.0 mGy, respectively ( P = 0.06). Qualitatively, PCCT VNC images had better overall image quality, image noise, small structure delineation, noise texture, and fewer artifacts (all P < 0.00001). Virtual noncontrast images from PCCT had lower attenuation (all P < 0.05), noise ( P = 0.006), and higher CNR ( P < 0.0001-0.04). Contrast-enhanced structures had lower SNR on PCCT ( P = 0.001, 0.002), reflecting greater contrast removal. The SNRfat (nonenhancing) was higher for PCCT than EI-DECT ( P < 0.00001). Virtual noncontrast images from PCCT had improved image quality, lower noise, improved CNR and SNR compared with those derived from EI-DECT.

Photon-counting detector CT allows significant reduction in radiation dose while maintaining image quality and noise on non-contrast chest CT

PurposeTo investigate if clinical non-contrast chest CT studies obtained with PCD CT using much lower radiation exposure can achieve the same image quality as with the currently established EID protocol. Materials/methodsA total of seventy-one patients were identified who had a non-contrast chest computed tomography (CT) done on PCD CT and EID CT scanners within a 4-month interval. Five fellowship trained chest radiologists, blinded to the scanner details were asked to review the cases side-by-side and record their preference for images from either the photon-counting-detector (PCD) CT or the energy-integrating detector (EID) CT scanner. ResultsThe median CTDIvol for PCD-CT system was 4.710 mGy and EID system was 7.80 mGy (p < 0.001). The median DLP with the PCD-CT was 182.0 mGy.cm and EID system was 262.60 mGy.cm (p < 0.001). The contrast to noise ratio (CNR) was superior on the PCD-CT system 59.2 compared to the EID-CT 53.3; (p < 0.001). Kappa-statistic showed that there was poor agreement between the readers over the image quality from the PCD and EID scanners (κ = 0.19; 95 % CI: 0.12 – 0.27; p < 0.001). Chi-square analysis revealed that 3 out of 5 readers showed a significant preference for images from the PCDCT (p ≤ 0.012). There was no significant difference in the preferences of two readers between EID-CT and PCD-CT images. ConclusionThe first clinical PCD-CT system allows a significant reduction in radiation exposure while maintaining image quality and image noise using a standardized non-contrast chest CT protocol.

Clinical Significance of Background Parenchymal Enhancement in Breast Cancer Risk Stratification.

Background parenchymal enhancement (BPE) is an established breast cancer risk factor. However, the relationship between BPE levels and breast cancer risk stratification remains unclear. To evaluate the clinical relationship between BPE levels and breast cancer risk with covariate adjustments for age, ethnicity, and hormonal status. Retrospective. 954 screening breast MRI datasets representing 721 women divided into four cohorts: women with pathogenic germline breast cancer (BRCA) mutations (Group 1, N = 211), women with non-BRCA germline mutations (Group 2, N = 60), women without high-risk germline mutations but with a lifetime breast cancer risk of ≥20% using the Tyrer-Cuzick model (Group 3, N = 362), and women with <20% lifetime risk (Group 4, N = 88). 3 T/axial non-fat-saturated T1, short tau inversion recovery, fat-saturated pre-contrast, and post-contrast T1-weighted images. Data on age, body mass index, ethnicity, menopausal status, genetic predisposition, and hormonal therapy use were collected. BPE levels were evaluated by two breast fellowship-trained radiologists independently in accordance with BI-RADS, with a third breast fellowship-trained radiologist resolving any discordance. Propensity score matching (PSM) was utilized to adjust covariates, including age, ethnicity, menopausal status, hormonal treatments, and prior bilateral oophorectomy. The Mann-Whitney U test, chi-squared test, and univariate and multiple logistic regression analysis were performed, with an odds ratio (OR) and corresponding 95% confidence interval. Weighted Kappa statistic was used to assess inter-reader variation. A P value <0.05 indicated a significant result. In the assessment of BPE, there was substantial agreement between the two interpreting radiologists (κ = 0.74). Patient demographics were not significantly different between patient groups after PSM. The BPE of Group 1 was significantly lower than that of Group 4 and Group 3 among premenopausal women. In estimating the BPE level, the OR of gene mutations was 0.35. Adjusting for potential confounders, the BPE level of premenopausal women with BRCA mutations was significantly lower than that of non-high-risk women. 3 TECHNICAL EFFICACY: Stage 3.

Interrater Agreement of CT Grading of Blunt Splenic Injuries: Does the AAST Grading Need to Be Reimagined?

Introduction: The Revised Organ Injury Scale (OIS) of the American Association for Surgery of Trauma (AAST) is the most widely accepted classification of splenic trauma. The objective of this study was to evaluate inter-rater agreement for CT grading of blunt splenic injuries. Methods: CT scans in adult patients with splenic injuries at a level 1 trauma centre were independently graded by 5 fellowship trained abdominal radiologists using the AAST OIS for splenic injuries - 2018 revision. The inter-rater agreement for AAST CT injury score, as well as low-grade (IIII) versus high-grade (IV-V) splenic injury was assessed. Disagreement in two key clinical scenarios (no injury versus injury, and high versus low grade) were qualitatively reviewed to identify possible sources of disagreement. Results: A total of 610 examinations were included. The inter-rater absolute agreement was low (Fleiss kappa statistic 0.38, P < 0.001), but improved when comparing agreement between low and high grade injuries (Fleiss kappa statistic of 0.77, P < .001). There were 34 cases (5.6%) of minimum two-rater disagreement about no injury vs injury (AAST grade ≥ I). There were 46 cases (7.5%) of minimum two-rater disagreement of low grade (AAST grade I-III) versus high grade (AAST grade IV-V) injuries. Likely sources of disagreement were interpretation of clefts versus lacerations, peri-splenic fluid versus subcapsular hematoma, application of adding multiple low grade injuries to higher grade injuries, and identification of subtle vascular injuries. Conclusion: There is low absolute agreement in grading of splenic injuries using the existing AAST OIS for splenic injuries.

Effect of a dedicated PI-QUAL curriculum on the assessment of prostate MRI quality

PurposeThe Prostate Imaging Quality (PI-QUAL) score is a metric to evaluate the diagnostic quality of multiparametric magnetic resonance imaging (MRI) of the prostate. This study evaluated the impact of a prostate MRI quality training lecture on the participant's ability to assess prostate MRI image quality. MethodsEighteen in-training-radiologists of varying experience in reviewing diagnostic prostate MRI assessed the image quality of ten examinations. Then, they attended a dedicated lecture on MRI quality assessment using the PI-QUAL score. After the lecture, the same participants evaluated the image quality of a new set of ten scans applying the PI-QUAL score. Results were assessed using receiver operating characteristic (ROC) analysis. The reference standard was the PI-QUAL score assessed by a fellowship trained abdominal radiologist with experience in reading prostate MRI. ResultsThere was a significant improvement in the average area under the curve (AUC) for assessment of prostate MRI image quality from baseline (0.82; [0.576 – 0.888]) to post teaching (1.0; [0.954–1]), with an improvement of 0.18 (p < 0.03). When ROC curves were computed for different cohorts stratified based on year of training, difference ranged from 0.48 for second year residents to 0.32 for fourth year residents (p < 0.001–0.01). For abdominal imaging fellows, the pre-teaching AUC was 0.9 [0.557–1] and post teaching AUC was 1 [0.957–1], a difference of 0.1 (p = 0.20). ConclusionsA dedicated lecture on PI-QUAL improved the ability of radiologists-in-training to assess prostate MRI image quality, with variable impact depending on year of training.

Emergency department imaging utilization of cancer patients treated with bevacizumab: single-institution 8-year experience.

This study aims to highlight the presentations, imaging, and clinical outcomes of cancer patients presenting to the emergency department (ED) while receiving bevacizumab (Avastin) therapy. Our retrospective study was based on data from a single institution to identify cancer patients who presented acutely to the ED between 2014 and 2021 within 3months of beginning bevacizumab who subsequently received diagnostic imaging with CT, MRI, ultrasound, and/or nuclear medicine ventilation/perfusion (VQ) scans. Data gathered included presenting symptoms grouped by body system, imaging impressions, and clinical outcomes, including hospitalization and discontinuation of bevacizumab after each ED visit. Imaging examinations and patient charts were reviewed by a team of fellowship-trained radiologists, radiology residents, and medical students. A total of 84 patients who presented to the ED were included for analysis. This included 32 (38.1%) males and 52 (61.9%) females, with a mean age of 61.2years and an age range of 29-91years. Neurological symptoms were the most common presenting symptoms, followed by abdominal symptoms and respiratory symptoms. Head imaging with CT and MRI was the most common imaging ordered with 55 total examinations, followed by abdominal imaging with 37 CT abdomen/pelvis (A/P) examinations, and then CT chest imaging with 22 examinations. Imaging revealed a serious adverse drug reaction in 21 (25.0%) patients, disease progression in 19 (22.6%), and no acute imaging findings in 44 (52.4%) patients. Imaging diagnoses were significantly associated with treatment planning, with a positive determination of bevacizumab-related serious adverse reaction on imaging leading to discontinuation of bevacizumab (p = 0.001). Multimodality imaging was a commonly used assessment tool for cancer patients receiving bevacizumab who presented to the ED. Imaging played a crucial role in diagnosis in these patients, especially of treatment-related serious adverse reactions and disease progression. Positive imaging findings of serious adverse reactions affected patient management including discontinuation of bevacizumab.

Effects of delayed callback from screening mammography due to the COVID-19 pandemic

ObjectiveTo determine the frequency and distinguishing imaging characteristics of breast cancers detected on screening mammography which was initially evaluated as a probably benign lesion and the workup was delayed due to the COVID-19 pandemic. Materials and methodsREB-approved multicenter retrospective screening mammography studies and patient's chart review carried out between February 2020 and March 2020. According to an institutional decision, the frequency and imaging findings deemed probably benign on screening mammography after review by a breast fellowship-trained radiologist with workup deferred until after the first pandemic wave plateau in late July 2020 were recorded. Results were correlated with histopathology if tissue sample performed or an uneventful 2 years follow-up. Descriptive statistical analysis was used to describe the retrieved data set. ResultsOut of 1816 mammography screening between February 2020 and March 2020, 99 women, median age 58 years (range 35–84), 99 mammography had possibly benign findings with workup delayed, and two patients, age 49 and 56, had cancers (2.02%), misinterpreted as benign findings. Both malignant cases were focal asymmetries, with pathology of invasive ductal carcinoma, 12 mm and 9 mm in size. No in-situ carcinoma was detected. ConclusionThe low rate of cancer detected suggests that a delay callback may be a reasonable option for some likely benign findings when immediate callback is not an option, such as during a pandemic. Larger studies would be helpful to support our findings and may allow us to translate the adoption of such a model during potential future pandemic. Clinical relevanceThe results of this study may be helpful for a future situation when delaying a call back from screening mammography is again required.