Axial T1W Research Articles

Peranan Teknik Compressed Sense (CS) pada Pemeriksaan MRI Lumbosacral dengan Kasus Hernia Nucleus Pulposus (HNP)

Background: The number of Lumbosacral MRI examinations at the Radiology Department of the Regional General Hospital of West Nusa Tenggara Province averages 80 patients per month, with the most common case being Hernia Nucleus Pulposus (HNP). The normal duration for each examination is 17-20 minutes. Compressed Sense (CS) was always activated during the author's observation of these examinations, reducing the total scan time for Lumbosacral MRI examinations to 8 minutes. In some MRI cases, there are challenges with non-cooperative patients, such as traumatic cases and being unable to supine position, which causes moving artifacts and makes image results blur, activating the CS technique can solve this problem making examination times faster. The research aims to analyze and describe the technique, the role of the technique, as well as the advantages and disadvantages of the CS technique in Lumbosacral MRI examinations for HNP cases.Methods: This research is qualitative descriptive research with a case study and literature review approach. use 3 patients, 3 radiographers, dan 3 radiologists, do in March to April 2024. Data was collected by observation, deep interviews, and questionnaires for radiologists about image quality.Result: Three patients with clinical HNP underwent Lumbosacral MRI examinations without any special preparation. The Lumbosacral MRI protocol includes Survey, Coronal T2W TSE, Sagittal T1W TSE, Sagittal T2W TSE, Sagittal T2W TSE SPIR, Axial T1W TSE, Axial T2W TSE, and MYELO Radial. The protocols use the CS technique with a reduction score of 1.4, except MYEOLO Radial, which can reduce scan time to 7-10 minutes without decreasing image quality. The sequences used serve to provide anatomical information and pathology in the lumbosacral area.Conclusions: Lumbosacral MRI examinations using the Compressed Sense technique can shorten the examination time without significantly reducing the quality of the images produced, it proved by the questionnaire result. This can increase patient comfort during the examination. The use of reduction values in this CS technique must be considered as it can increase the value of Peripheral Nerve Stimulation (PNS).

Clinical MR imaging of patients with spinal hardware at 0.55T: comparison of diagnostic assessment and metal artifact appearance with 1.5T.

The aim of this study is to assess inter-reader agreement of imaging findings and compare readers' assessment of image quality (IQ) and appearance of metal artifact (MA) in patients with spinal implants between 0.55T and 1.5T MRI. Patients imaged on Siemens Healthineers Magnetom Free.Max 0.55T (n = 42; avg. age 55 yrs.) with spinal hardware between 12/2021 and 3/2024 were included. Of these, 18 patients had a paired exam at 1.5T. All exams were reviewed independently by three neuroradiologists (R1-3). Readers selected imaging findings from a pick-list and rated sequences using a 4-point Likert scale for IQ and MA. At both 0.55T and 1.5T, raw agreement for the following findings ranged between 81 and 95%: cord signal abnormality, osteomyelitis/discitis, osseous metastatic disease, and compression fracture. Agreement on post-operative fluid collection and spinal canal stenosis was 64.3% and 66.7% at 0.55T, and 77.7% and 50.0% at 1.5T. Agreement on neural foraminal stenosis was low in both cohorts, 47.6% and 33.3% at 0.55T and 1.5T. No sequence at 0.55T was rated inferior to 1.5T in IQ or MA. Sequences rated higher at 0.55T compared to 1.5T were as follows for IQ: sagittal T1w TSE (R1) and as follows for MA: axial T1w TSE (R1, R2), sagittal T1w TSE (R1), axial T2w TSE (R1), sagittal T1w TSE Dixon post-contrast (R2), sagittal T2w STIR (R2: p = 0.01). Imaging patients with spinal hardware at 0.55T results in comparable inter-reader agreement for clinically-relevant imaging findings and equivalent or improved image quality compared to 1.5T.

The feasibility of high-resolution organ-axial T2-weighted MRI when combined with federation of gynecology and obstetrics (FIGO) classification of uterine fibroid patients.

Correctly classifying uterine fibroids is essential for treatment planning. The objective of this study was to assess the accuracy and reliability of the FIGO classification system in categorizing uterine fibroids via organ-axial T2WI and to further investigate the factors associated with uterine compression. A total of 130 patients with ultrasound-confirmed fibroids were prospectively enrolled between March 2023 and May 2024. These patients underwent MR examinations, including body-axial T2W (sagittal and axial) and organ-axial T2W (high resolution with oblique coronal and double oblique axial). For postprocessing, the interobserver agreements between two radiologists and the interagreements between two MR examinations and operational descriptions were evaluated via kappa statistics. The accuracy of axial and organ-axial T2W assessments in the FIGO classification of uterine fibroids was compared when surgical outcomes were used as the gold standard. The Kruskal‒Wallis test was used to compare the differences in cavity deformation across various FIGO classifications. Spearman's rank correlation test was used to analyze the correlation between the FIGO classification and the parameters of uterine cavity deformation. In total, 170 fibroids from 130 patients were included. Compared with body-axial T2WI, organ-axial T2WI showed better interobserver agreement and greater interagreements with operational descriptions, with kappa values of 0.877 (P = 0.04) and 0.932 (P = 0.037), respectively. The accuracy of the organ-axial T2WI assessment in determining the FIGO classification of uterine fibroids was greater than that of the body-axial T2WI assessment, with an accuracy of 92.9% (P < 0.01). Thirty-two (38.1%) fibroids showed cavity deformation according to organ-axial T2WI, including fibroids with FIGO types 0-7 and 2-5. Among these factors, the size of the fibroids (S), base width (B), depth of compression (D), D/B, D/S, and compression angle (A) significantly differed among the different FIGO types of fibroids (P < 0.05). Compression angle exhibited a linear correlation with the FIGO type (P < 0.001). Compared with body-axial T2WI, organ-axial T2WI provides greater accuracy on the basis of the FIGO classification, which is more consistent with surgical outcomes. Given the excellent reliability and accuracy of the preoperative FIGO classification, organ-axial T2WI can contribute to treatment planning.

Facet joint tropism in degenerative lumbar scoliosis: a retrospective case-control study.

To investigate the association between lumbar degenerative scoliosis and the dural sac cross-sectional area (DSCA), the lumbar canal anterior-posterior (LCAP) diameter, and the neural foraminal cross-sectional area (NFCA) in relation to facet joint tropism (FJT). In a retrospective case-control study, we analyzed data from 160 patients referred for lumbar magnetic resonance imaging (MRI) between January 2020 and December 2022. Cobb's angle on anteroposterior lumbosacral X-ray is served to identify the presence of degenerative lumbar scoliosis-Cobb's angle exceeding 10 degrees-, and axial T2W MRI is implemented to evaluate facet joint angles and tropism-defined as a difference exceeding 10 degrees between the facet joint angles at each level-, DSCA, LCAP, and NFCA. FJT was much more common in patients with degenerative lumbar scoliosis (69%) than in controls (14%). The frequency of FJT also incremented with the increasing severity of the scoliotic curve. We observed that LCAP and NFCA were significantly smaller in cases with FJT. However, no statistically significant difference was found in DSCA related to FJT. Age and gender did not exhibit significant associations with degenerative lumbar scoliosis, and no correlation was detected between different Cobb's angle groups and age. These findings underscore the importance of considering FJT as a potential contributing factor to degenerative lumbar scoliosis and may have implications for clinical diagnosis and management. Prospective research with larger and more diverse cohorts is needed to further investigate this complex relationship and its impact on lumbar spinal health.

Development and Validation of a Modality-Invariant 3D Swin U-Net Transformer for Liver and Spleen Segmentation on Multi-Site Clinical Bi-parametric MR Images.

To develop and validate a modality-invariant Swin U-Net Transformer (UNETR) deep learning model for liver and spleen segmentation on abdominal T1-weighted (T1w) or T2-weighted (T2w) MR images from multiple institutions for pediatric and adult patients with known or suspected chronic liver diseases. In this IRB-approved retrospective study, clinical abdominal axial T1w and T2w MR images from pediatric and adult patients were retrieved from four study sites, including Cincinnati Children's Hospital Medical Center (CCHMC), New York University(NYU), University of Wisconsin (UW) and University of Michigan / Michigan Medicine (UM). The whole liver and spleen were manually delineated as the ground truth masks. We developed a modality-invariant 3D Swin UNETR using a modality-invariant training strategy, in which each patient's T1w and T2w MR images were treated as separate training samples. We conducted both internal and external validation experiments. A total of 241 T1w and 339 T2w MR sequences from 304 patients (age [mean standard deviation], 31.8 20.3years; 132 [43%] female) were included for model development. The Swin UNETR achieved a Dice similarity coefficient (DSC) of 0.95 ± 0.02 on T1w images and 0.93 ± 0.05 on T2w images for liver segmentation. This is significantly better than the U-Net model (0.90 ± 0.05, p < 0.001 and 0.90 ± 0.13, p < 0.001, respectively). The Swin UNETR achieved a DSC of 0.88 ± 0.12 on T1w images and 0.93 ± 0.10 on T2w images for spleen segmentation, and it significantly outperformed a modality-invariant U-Net model (0.80 ± 0.18, p = 0.001 and 0.88 ± 0.12, p = 0.002, respectively). Our study demonstrated that a modality-invariant Swin UNETR model can segment the liver and spleen on routinely collected clinical bi-parametric abdominal MR images from children and adult patients.

Usage of Magnetic Resonance Imaging-Based Texture Analysis Features in Discrimination of Benign and Malignant Sinonasal Tumors

Aim: The objective of this study was to differentiate between benign and malignant sinonasal tumors using magnetic resonance imaging (MRI)-based texture analysis features. Materials and Method: Histopathologically proven benign or malignant sinonasal tumor patients were included in the study from MRI examinations performed between January 2013 and December 2020. Inclusion criteria included a tumor size of at least 1 cm and preoperative magnetic resonance imaging with axial T1W, axial fat-suppressed T2W, and axial T1W postcontrast sequences. After the images were transferred to a dedicated workstation, texture analysis calculations were performed. Differences between benign and malignant groups were compared. Results: The mean age of 37 patients (8 female, 29 male) included in the study was 50.8 ± 21.9 years. In our study, we found no statistically significant difference between malignant and benign sinonasal tumors in nine tissue analysis parameters obtained by MRI. Conclusion: MRI-based texture analysis needs identical MRI protocols for evaluating tumors. MRI-based texture analysis is not a useful diagnostic tool to discriminate between benign and malignant sinonasal tumors when specific pathologic types are not selected and scanning protocols are not identical.

Abstract 4135968: Radiomic features of skeletal muscle on prostate T1-Weighted MRI associated with MACE outcomes in prostate cancer patients undergoing hormonal therapy

Background: Patients with high-risk prostate cancer (PC) who undergo hormonal therapy(HT) frequently die of major adverse cardiovascular events (MACE). Skeletal muscle on abdominal T1-weighted MRI (T1W) has been shown to be associated with cardiovascular fitness. Aims: To quantify heterogeneity associated with skeletal muscle tissue composition on prostate MRI patients undergoing HT using computationally derived radiomic features and identify their association with MACE. Methods: Cohort of N=58 men diagnosed with PC who underwent a 3 Tesla pre-treatment multi-parametric MRI followed by HT and followed up for MACE events were identified. MACE is defined as a composite of cardiovascular death, atrial fibrillation, myocardial infarction, ischemic stroke, heart failure, coronary artery disease, and peripheral vascular disease. Regions of interest (ROI) of skeletal muscle, including the obturator externus, pectineus, and the adductor group of muscles, were delineated on axial T1W under the guidance of an experienced radiologist. A set of 120 radiomic features, including gray level statistics, co-occurrence, wavelet, and texture energy-based features, were extracted within the ROI which quantifies underlying subvisual texture-based heterogeneity. Radiomics associated with MACE events were identified using the Wilcoxon rank-sum test and univariate Cox-regression (p&lt;0.05). Results: Of the N=58 patients included in this study, 18 experienced MACE. The most common MACE event was AF (8.6%). Median-time-to-MACE event was 7.3 years (6.2-8.2). 3 radiomic features (Table 1) quantifying the heterogeneity of skeletal muscle on prostate T1W were observed to be associated with MACE. Specifically, we observe that first order features have a lower response and wavelet features have a lower response in MACE patients which suggests a higher degree of local deformations and heterogeneity in skeletal tissue compared to non-MACE patients. Conclusions: Results from our study suggest that radiomics quantified texture characteristics of skeletal muscle tissue may indicate cardiovascular fitness, reflecting the likelihood of experiencing MACE following initiation of HT in PC men. Pre-treatment identification of PC patients at high risk of MACE may allow for alternative treatment options improving cardiovascular outcomes. Future studies will involve exploring larger, multi-site cohorts and machine learning modeling to determine cardiovascular risk.

Detecting Clinically Significant Prostate Cancer in PI-RADS 3 Lesions Using T2w-Derived Radiomics Feature Maps in 3T Prostate MRI.

Prostate Imaging Reporting and Data System version 2.1 (PI-RADS) category 3 lesions are a challenge in the clinical workflow. A better detection of the infrequently occurring clinically significant prostate cancer (csPCa) in PI-RADS 3 lesions is an important objective. The purpose of this study was to evaluate if feature maps calculated from T2-weighted (T2w) 3 Tesla (3T) MRI can help detect csPCa in PI-RADS category 3 lesions. In-house biparametric 3T prostate MRI examinations acquired between January 2019 and June 2023 because of elevated prostate-specific antigen (PSA) levels were retrospectively screened. Inclusion criteria were a PI-RADS 3 lesion and available results of an ultrasound-guided targeted and systematic biopsy. Exclusion criteria were a simultaneous PI-RADS category 4 or 5 lesion and hip replacement. Target lesions with the International Society of Urological Pathology (ISUP) grade group 1 were rated clinically insignificant PCa (ciPCa) and ≥2 csPCa. This resulted in 52 patients being included in the final analysis, of whom 11 (21.1%), 8 (15.4%), and 33 (63.5%) patients had csPCa, ciPCa, and no PCa, respectively, with the latter two groups being combined as non-csPCa. Eight of the csPCas were located in the peripheral zone (PZ) and three in the transition zone (TZ). In the non-csPCa group, 29 were located in the PZ and 12 in the TZ. Target lesions were marked with volumes of interest (VOIs) on axial T2w images. Axial T2w images were then converted to 93 feature maps. VOIs were copied into the maps, and feature quantity was retrieved directly. Features were tested for significant differences with the Mann-Whitney U-test. Univariate models for single feature performance and bivariate models implementing PSA density (PSAD) were calculated. Ten map-derived features differed significantly between the csPCa and non-csPCa groups (AUCs: 0.70-0.84). The diagnostic performance for TZ lesions (AUC: 0.83-1.00) was superior to PZ lesions (AUC: 0.74-0.85). In the bivariate models, performance in the PZ improved with AUCs >0.90 throughout. Parametric feature maps alone and as bivariate models with PSAD can (?) noninvasively identify csPCa in PI-RADS 3 lesions and could serve as a quantitative tool reducing ambiguity in PI-RADS 3 lesions.

AI-ADC: Channel and Spatial Attention-Based Contrastive Learning to Generate ADC Maps from T2W MRI for Prostate Cancer Detection.

Apparent Diffusion Coefficient (ADC) maps in prostate MRI can reveal tumor characteristics, but their accuracy can be compromised by artifacts related with patient motion or rectal gas associated distortions. To address these challenges, we propose a novel approach that utilizes a Generative Adversarial Network to synthesize ADC maps from T2-weighted magnetic resonance images (T2W MRI). By leveraging contrastive learning, our model accurately maps axial T2W MRI to ADC maps within the cropped region of the prostate organ boundary, capturing subtle variations and intricate structural details by learning similar and dissimilar pairs from two imaging modalities. We trained our model on a comprehensive dataset of unpaired T2-weighted images and ADC maps from 506 patients. In evaluating our model, named AI-ADC, we compared it against three state-of-the-art methods: CycleGAN, CUT, and StyTr2. Our model demonstrated a higher mean Structural Similarity Index (SSIM) of 0.863 on a test dataset of 3240 2D MRI slices from 195 patients, compared to values of 0.855, 0.797, and 0.824 for CycleGAN, CUT, and StyTr2, respectively. Similarly, our model achieved a significantly lower Fréchet Inception Distance (FID) value of 31.992, compared to values of 43.458, 179.983, and 58.784 for the other three models, indicating its superior performance in generating ADC maps. Furthermore, we evaluated our model on 147 patients from the publicly available ProstateX dataset, where it demonstrated a higher SSIM of 0.647 and a lower FID of 113.876 compared to the other three models. These results highlight the efficacy of our proposed model in generating ADC maps from T2W MRI, showcasing its potential for enhancing clinical diagnostics and radiological workflows.

Diagnostic Value of Pericholedochal Hypointense Ring Sign in MRI T2W Images in Cases of Pancreatic Ductal Adenocarcinoma.

To determine the value of hypointense pericholedocal ring sign in magnetic resonance imaging (MRI) T2W sequence images in the diagnosis of pancreatic ductal adenocarcinoma (PDA). Retrospective observational study. Place and Duration of the Study: Department of Radiology, Bakirkoy Dr Sadi Konuk Training and Research Hospital, Istanbul, Turkiye, from January 2016 and March 2022. Retrospective analysis of MRI scans was performed on 70 patients with postoperative histopathological confirmation of a diagnosis of periampullary cancer. The patients' demographic information, the results of their histopathological examinations, and the findings of their MRIs were recorded. The results of the MRI were statistically analysed and compared between the PDA and the non-PDA groups. The study included 43 (61.4%) male and 27 (38.5%) female patients, with a mean age of 62.2 ± 8.4 years. The means of Wirsung diameter and tumour diameter were significantly higher in PDA group (p = 0.034, p = 0.010, respectively). A progressive contrast enhancement pattern of 95.3% was observed in PDA group, while 40.7% rapid contrast enhancement pattern was observed in the non-PDA group. Hypointense pericholedochal ring sign, observed in T2W sequences, was detected in 74.2% (n = 32) of the PDA group and 11.1% (n = 3) of the non-PDA group, and the findings were statistically significant (p <0.001). Hypointense pericholedochal ring sign in axial T2W sequences in periampullary tumours is a complementary MRI finding in the distinction between the PDA and the non-PDA groups. Magnetic resonance imaging, Pancreatic ductal adenocarcinoma, Periampullary tumours, Pericholedochal ring sign.

Implementing a rapid cord compression Magnetic Resonance Imaging protocol in the emergency department: Lessons learned.

(1) Evaluate efficacy of an abbreviated total spine protocol in triaging emergency department (ED) patients through retrospective evaluation. (2) Describe patient outcomes following implementation of a rapid cord compression protocol. (1) All contrast-enhanced total spine magnetic resonance imaging studies (MRIs) performed on ED patients (n = 75) between 10/1-12/31/2022 for evaluation of cord compression were included. Two readers with 6 and 5years of experience blindly reviewed the abbreviated protocol (comprised of sagittal T2w and axial T2w sequences) assessing presence of cord compression or severe spinal canal stenosis. Ground truth was consensus by a neuroradiology fellow and 2 attendings. (2) The implemented rapid protocol included sagittal T1w, sagittal T2w Dixon and axial T2w images. All ED patients (n = 85) who were imaged using the rapid protocol from 5/1-8/31/2023 were included. Patient outcomes and call-back rates were determined through chart review. (1) Sensitivity and specificity for severe spinal canal stenosis and/or cord compression was 1.0 and 0.92, respectively, for reader 1 and 0.78 and 0.85, respectively, for reader 2. Negative predictive value was 1.0 and 0.97 for readers 1 and 2, respectively. (2) The implemented rapid cord compression protocol resulted in 60% reduction in imaging time at 1.5T. The call-back rate for additional sequences was 7%. In patients who underwent surgery, no additional MRI images were acquired in 82% of cases (9/11). Implementing an abbreviated non-contrast total spine protocol in the ED results in a low call-back rate with acquired MRI images proving sufficient for both triage and treatment planning in most patients.

Prognostic Value of MRI Assessment of Residual Peritumoral Edema in Breast Cancer Treated With Neoadjuvant Chemotherapy.

Peritumoral edema (PE) identified on T2-weighted breast MRI is a factor for poor prognosis in breast cancer. To assess the prognostic value of residual PE (rPE) in patients with PE positive breast cancer prior to neoadjuvant chemotherapy (NACT) who subsequently underwent curative surgery. Retrospective. In total, 128 patients with nonmetastatic invasive breast cancer who underwent breast MRI before and after NACT. Axial precontrast 2D fast spin echo T2W fat-suppressed sequence. Axial dynamic 3D gradient echo T1W fat-suppressed sequence. PE was diagnosed when a signal intensity as high as water was detected surrounding the tumor on a T2-weighted breast MRI. PE was qualitatively evaluated by three readers with more than 20 years of experience in interpreting breast field imaging findings. Residual cancer burden (RCB) were assessed post-NACT. Recurrence-free survival (RFS) and overall survival (OS) were evaluated as the endpoints of this study. Chi-square test; Kaplan-Meier method, log-rank test, and Cox proportional hazard model. A P-value <0.05 was considered statistically significant. Pre-PE was observed in 64 out of 128 patients. Of these, rPE was observed in 21. In the log-rank test, breast cancer with rPE had significantly worse RFS and OS than that without rPE. Cox proportional hazard analysis identified rPE as a significant prognostic factor for recurrence (hazard ratio, 11.6; 95% confidence interval [CI], 3.05-43.8) and death (hazard ratio, 17.8; 95% CI, 3.30-96.3). Breast cancer with rPE had significant worse RFS and OS than that without rPE in RCB class II, and significant worse OS in pathological complete response, class I and class II in the log-rank test. rPE on a T2-weighted breast MRI was a significant factor for breast cancer recurrence and death in patients with pre-PE-positive breast cancer treated with NACT. Stage 2.

Infant head and brain segmentation from magnetic resonance images using fusion-based deep learning strategies

Magnetic resonance (MR) imaging is widely used for assessing infant head and brain development and for diagnosing pathologies. The main goal of this work is the development of a segmentation framework to create patient-specific head and brain anatomical models from MR images for clinical evaluation. The proposed strategy consists of a fusion-based Deep Learning (DL) approach that combines the information of different image sequences within the MR acquisition protocol, including the axial T1w, sagittal T1w, and coronal T1w after contrast. These image sequences are used as input for different fusion encoder–decoder network architectures based on the well-established U-Net framework. Specifically, three different fusion strategies are proposed and evaluated, namely early, intermediate, and late fusion. In the early fusion approach, the images are integrated at the beginning of the encoder–decoder architecture. In the intermediate fusion strategy, each image sequence is processed by an independent encoder, and the resulting feature maps are then jointly processed by a single decoder. In the late fusion method, each image is individually processed by an encoder–decoder, and the resulting feature maps are then combined to generate the final segmentations. A clinical in-house dataset consisting of 19 MR scans was used and divided into training, validation, and testing sets, with 3 MR scans defined as a fixed validation set. For the remaining 16 MR scans, a cross-validation approach was adopted to assess the performance of the methods. The training and testing processes were carried out with a split ratio of 75% for the training set and 25% for the testing set. The results show that the early and intermediate fusion methodologies presented the better performance (Dice coefficient of 97.6 ± 1.5% and 97.3 ± 1.8% for the head and Dice of 94.5 ± 1.7% and 94.8 ± 1.8% for the brain, respectively), whereas the late fusion method generated slightly worst results (Dice of 95.5 ± 4.4% and 93.8 ± 3.1% for the head and brain, respectively). Nevertheless, the volumetric analysis showed that no statistically significant differences were found between the volumes of the models generated by all the segmentation strategies and the ground truths. Overall, the proposed frameworks demonstrate accurate segmentation results and prove to be feasible for anatomical model analysis in clinical practice.

Diagnostic Contribution of Additional Sequences to the Evaluation of Cord Lesions in Patients with Cervical Spinal Multiple Sclerosis in Turkey: A Retrospective Study.

Multiple Sclerosis (MS) is the most common cause of non-traumatic disability in young adults. Spinal cord involvement is observed in 55-75% of patients with MS. To identify the strengths and shortcomings of sagittal phase-sensitive inversion recovery (PSIR), sagittal proton density/T2-weighted (PD/T2W), and axial turbo inversion recovery magnitude (TIRM) sequences in the detection of cervical MS plaques by comparing with routine sequences (axial and sagittal T2W, sagittal T1W, sagittal TIRM, fat-suppressed contrast T1W) and therefore determine their diagnostic contributions. A total of 48 patients in whom additional magnetic resonance imaging (MRI) sequences were obtained for the diagnosis of cervical MS were retrospectively identified and included in the study. A total of 111 MS plaques were analyzed in terms of visibility, number, size, border sharpness, and intensity ratio based on the routine and additional MRI sequences. The evaluation of the images was independently undertaken by two radiologists. The highest visibility was provided by sagittal PSIR, sagittal TIRM, and axial TIRM sequences (P < 0.05 for all additional sequences). Seven lesions in PD/T2W and four lesions in axial T2W sequences were unable to be detected. Lesions seen in sagittal and axial TIRM sequences were larger than the others. The sharpest borders were determined in the axial TIRM sequence, and the most diffuse borders in the PD/T2W sequence. In intensity ratio, the sagittal PSIR sequence revealed the most significant contrast difference. The sagittal PSIR sequence may improve the detection of cervical MS plaques due to the improved visibility and intensity ratios. The axial TIRM sequence may be more useful than routine axial T2W in the evaluation of visibility, border sharpness, and size measurement of MS plaques.

Comparative Performance of 2018 LI-RADS versus Modified LIRADS (mLI-RADS): An Individual Participant Data Meta-Analysis.

LI-RADS version 2018 (v2018) is used for non-invasive diagnosis of hepatocellular carcinoma (HCC). A recently proposed modification (known as mLI-RADS) demonstrated improved sensitivity while maintaining specificity and positive predictive value (PPV) of LI-RADS category 5 (definite HCC) for HCC. However, mLI-RADS requires multicenter validation. To evaluate the performance of v2018 and mLI-RADS for liver lesions in a large, heterogeneous, multi-national cohort of patients at risk for HCC. Systematic review and meta-analysis using individual participant data (IPD) [Study Protocol: https://osf.io/duys4]. 2223 observations from 1817 patients (includes all LI-RADS categories; females = 448, males = 1361, not reported = 8) at elevated risk for developing HCC (based on LI-RADS population criteria) from 12 retrospective studies. 1.5T and 3T; complete liver MRI with gadoxetate disodium, including axial T2w images and dynamic axial fat-suppressed T1w images precontrast and in the arterial, portal venous, transitional, and hepatobiliary phases. Diffusion-weighted imaging was used when available. Liver observations were categorized using v2018 and mLI-RADS. The diagnostic performance of each system's category 5 (LR-5 and mLR-5) for HCC were compared. The Quality Assessment of Diagnostic Accuracy Studies version 2 (QUADAS-2 was applied to determine risk of bias and applicability. Diagnostic performances were assessed using the likelihood ratio test for sensitivity and specificity and the Wald test for PPV. The significance level was P < 0.05. 17% (2/12) of the studies were considered low risk of bias (244 liver observations; 164 patients). When compared to v2018, mLR-5 demonstrated higher sensitivity (61.3% vs. 46.5%, P < 0.001), similar PPV (85.3% vs. 86.3%, P = 0.89), and similar specificity (85.8% vs. 90.8%, P = 0.16) for HCC. This study confirms mLR-5 has higher sensitivity than LR-5 for HCC identification, while maintaining similar PPV and specificity, validating the mLI-RADS proposal in a heterogeneous, international cohort. 3 TECHNICAL EFFICACY: Stage 2.

Technical and Diagnostic Performance of Rapid MRI for Evaluation of Appendicitis in a Pediatric Emergency Department

Rationale MRI is increasingly used for diagnosis of pediatric appendicitis in theemergency care setting. Scan and room time are important to optimize workflow,especially in situations with limited MRI availability and accessibility. To describe our process to optimize and implement a rapid, non-contrast, free-breathing MRI protocol for appendicitis and to characterize the accuracy fordiagnosis. Initial MRI protocol implemented for suspected appendicitis included five respiratory-triggered axial and coronal single shot fast spin echo (SSFSE) and radialT2W sequences with and without fat suppression (FS). This protocol was reassessedbased on image quality. Subsequently, the coronal and axial T2W SSFSE FS sequence were removed. A three-sequence exam comprised the rapid MRI appendicitisprotocol used for the remainder of the study. All examinations were performed on a 1.5T scanner. For all examinations, the following information was obtained: scan time, diagnosis ofappendicitis (by radiology report), surgery and pathology reports, and alternativediagnoses documented in radiology reports. MRI examination scan durations werecompared between the five-sequence and three-sequence protocols, with Mann-Whitney U test, and proportions of false diagnoses were compared toFisher's exact test. 216 examinations were performed; 21 and 195 performed with five-and three-sequence protocol, respectively. The median duration of the five-sequence protocol was 20 (16.9-23.5) minutes vs.11 (9.5-13) minutes for the threesequence protocol (p<0.0001). The majority (n=157, 80.5% of 195) of examinations were performed in a goal time of<15min. 23 examinations took longer than 20min (n=12, n=11 for the three-and five-sequence protocols, respectively) were due to repeat sequences or addition of non-standardsequences (requested by interpreting radiologist). 27 (90%) of the 30 reported positive cases were confirmed by pathology. There were threefalse-positive diagnoses (all three-sequence protocol exams) and onefalse-negativediagnosis (five-sequence protocol exam). Alternative diagnoses, including pancreatitis,omental infarct, masses, and ovarian pathology, were made in 42 (19%) cases. A three-sequence, non-contrast, free- breathing MRI examination can beperformed in less than 15min in the emergency department and has highdiagnostic accuracy for acute appendicitis in children and young adults.

Quality assessment of routine brain imaging at 0.55 T: initial experience in a clinical workflow.

The purpose of this study was to assess the quality of clinical brain imaging in healthy subjects and patients on an FDA-approved commercial 0.55 T MRI scanner, and to provide information about the feasibility of using this scanner in a clinical workflow. In this IRB-approved study, brain examinations on the scanner were prospectively performed in 10 healthy subjects (February-April 2022) and retrospectively derived from 44 patients (February-July 2022). Images collected using the following pulse sequences were available for assessment: axial DWI (diffusion-weighted imaging), apparent diffusion coefficient maps, 2D axial fluid-attenuated inversion recovery images, axial susceptibility-weighted images (both magnitude and phase), sagittal T1 -weighted (T1w) Sampling Perfection with Application Optimized Contrast images, sagittal T1w MPRAGE (magnetization prepared rapid gradient echo) with contrast enhancement, axial T1w turbo spin echo (TSE) with and without contrast enhancement, and axial T2 -weighted TSE. Two readers retrospectively and independently evaluated image quality and specific anatomical features in a blinded fashion on a four-point Likert scale, with a score of 1 being unacceptable and 4 being excellent, and determined the ability to answer the clinical question in patients. For each category of image sequences, the mean, standard deviation, and percentage of unacceptable quality images (<2) were calculated. Acceptable (rating ≥ 2) image quality was achieved at 0.55 T in all sequences for patients and 85% of the sequences for healthy subjects. Radiologists were able to answer the clinical question in all patients scanned. In total, 50% of the sequences used in patients and about 60% of the sequences used in healthy subjects exhibited good (rating ≥ 3) image quality. Based on these findings, we conclude that diagnostic quality clinical brain images can be successfully collected on this commercial 0.55 T scanner, indicating that the routine brain imaging protocol may be deployed on this system in the clinical workflow.

3.0 T prostate MRI: Visual assessment of 2D and 3D T2-weighted imaging sequences using PI-QUAL score

PurposeComparing 2D and 3D T2 weighted sequences in terms of image quality in 3.0 T MRI with readers of varied experiences, using PI-QUAL inspired criteria. Methods91 male patients with suspected prostate cancer (PCa) underwent diagnostic prostate MRI on a 3.0 T MR system using a 32-channel phased-array torso coil before prostate biopsy. MRI protocol included 3D T2w images, axial 2D T2w images, axial diffusion-weighted images (DWI) with the corresponding ADC apparent diffusion coefficient maps, and axial dynamic contrast enhanced images. 3D T2w and 2D T2w imaging were compared by 4 radiologists using a Likert scale for image quality (overall anatomy, delineation of capsule, seminal vesicles, ejaculatory ducts, sphincter muscle, artifacts), tumor delimitation and conspicuity. ResultsNo significant differences in terms of overall quality between 3D and 2D T2w images were found. However 2D T2w demonstrated higher rating than 3D T2w images as for the image quality of the external capsule, sphincter muscle and ejaculatory ducts delineation (p < 0.05). Conclusion3D T2w sequence can’t replace 2D T2w sequence, despite good quality images but it remains more prone to artifacts. Quality of 2D T2w sequences was substantially superior to 3D sequences for delineation of key structures as external capsule, sphincter muscle. The use of PI-QUAL criteria allows reproducible analysis of the quality of T2 weighted images.

PD35-07 DYNAMIC MRI URETHROGRAM: A NEW FRONTIER IN URETHRAL STRICTURE EVALUATION

You have accessJournal of UrologyCME1 Apr 2023PD35-07 DYNAMIC MRI URETHROGRAM: A NEW FRONTIER IN URETHRAL STRICTURE EVALUATION André Cavalcanti, Rafael Cobo, Gabriel Affonso, and Felipe Da Silva André CavalcantiAndré Cavalcanti More articles by this author , Rafael CoboRafael Cobo More articles by this author , Gabriel AffonsoGabriel Affonso More articles by this author , and Felipe Da SilvaFelipe Da Silva More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003333.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The urethral stricture is a disease that cause severe impact on the quality of life in male patients. As a disease were the definitive treatment is a surgical procedure, an adequate pre-operative image study for the surgical planning is essencial. The Retrograde Urethrogram has been the gold standard method for the urethral stricture evaluation during the paste decades. This method has limitations as technical points associated to failures to a precise measure of the stricture length/localization and the incapacity to evaluate the peri-urethral fibrosis. The objective of this study is to test the Dynamic MRI Urethrogram as a unique method to urethral stricture diagnostic and pre-operative evaluation. METHODS: A Group of 25 consecutive patients with a suspicion of urethral stricture disease were submitted to a Dynamic MRI Urethrogram as the unique image study to confirm the diagnosis, disease characterization and surgical planning. All patients were submitted to the same MRI protocol: peripheral venous access and hydration with at least 500 ml of saline solution to stimulate diuresis, installation of 20 ml to 40 ml of lidocaine gel through the meatus, noosing the balanoprepucial sulcus with a sterile gauze. After, routine sequences were performed: Axial T1w, Axial and Sagittal T2, SPACE coronal, MIP Sagittal, T2 Urographic effects techniques images obtained during rest and miccional strain, T1 FS Sagittal before and after gadolinium. All patients were submitted to a urethral reconstruction performed by the same surgeon: anastomotic urethroplasty in 16 patients (64%) and substitution urethroplasty with buccal mucosa graft in 9 patients (36%). RESULTS: In The Dynamic MRI Urethrogram was considered adequate for the definition of surgical proposal in all patients. A diagnostic of anterior urethra strictures was observed in 12 patients (48%) and posterior urethra strictures in 13 patients (53%). The surgeon observed a correspondence between MRI images and surgical findings regarding the location and length of the stricture in all patients. The Dynamic MRI Urethrogram was also adequate to evaluate the urethral caliber in the site of the stricture and the peri-urethral fibrosis. An advantage observed with the use of this method was the possibility to evaluate other organs, structures and the relation with the urethra and the stricture area as rectum, prostate and pubis. The Dynamic MRI Urethrogram also gives the possibility of 3 D reconstructions. CONCLUSIONS: The Dynamic MRI Urethrogram is an excellent method to evaluate the urethral stricture in different portions such anterior and posterior urethra with possible advantages over other methods as the precision measure of location, length, caliber and also evaluation of peri-urethral fibrose and relation with other organ and structures. All those characteristics are important to the surgical planning, specially using a unique image method. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e977 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information André Cavalcanti More articles by this author Rafael Cobo More articles by this author Gabriel Affonso More articles by this author Felipe Da Silva More articles by this author Expand All Advertisement PDF downloadLoading ...

Incidental findings involving the temporomandibular joint on computed tomography and magnetic resonance imaging.

The temporomandibular joint (TMJ) is frequently imaged in head and neck computed tomography (CT) and magnetic resonance imaging (MRI) studies. Depending on the indication for the study, an abnormality of the TMJ may be an incidental finding. These findings encompass both intra- and extra-articular disorders. They may also be related to local, regional or systemic conditions. Familiarity with these findings along with pertinent clinical information helps narrow the list of differential diagnoses. While definitive diagnosis may not be immediately apparent, a systematic approach contributes to improved discussions between clinicians and radiologists and better patient management.