Combined MRI Research Articles

Role of conventional magnetic resonance imaging and diffusion-weighted imaging in evaluation of breast lesions

Background and Aim This study aimed to evaluate the role of diffusion-weighted imaging (DWI) and apparent diffusion coefficient in diagnosis of the breast lesions. Patients and methods This study included 100 patients referred to the Radiology Department of Al-Azhar Assiut University Hospital from February 2018 to May 2020 for DWI MRI examination with a provisional diagnosis of breast lesions. All patients were recruited after meeting the inclusion criteria. They underwent clinical examination, mammography, ultrasonography, and contrast-enhanced MRI with DWI. Results Our study included 100 cases. The combined MRI protocol of dynamic contrast-enhanced (DCE)-MRI and DWI was true positive in 60 and true negative in 30 patients. The combined MRI protocol of DCE-MRI and DWI provided a sensitivity of 92%, a specificity of 90%, a positive predictive value of 95.8%, a negative predictive value of 81.8% and accuracy of 91.43%. In this study, the addition of DWI to standard DCE-MRI provided a 10% increase in the specificity of breast MRI, with a 4% decrease in the sensitivity. Conclusion DWI is a short unenhanced scan and had the highest specificity compared with other imaging modalities, as it reduced the false-positive results. It should be added to conventional breast MRI to increase the sensitivity and specificity of MRI.

PD50-06 A COMPARISON OF MRI FUSION BIOPSY PI-RADS SCORING SYSTEM TO EXACTVU MICRO-ULTRASOUND PRI-MUS SCORING SYSTEM IN IDENTIFYING PROSTATE CANCER: A SINGLE INSTITUTION RETROSPECTIVE ANALYSIS

You have accessJournal of UrologyProstate Cancer: Detection & Screening V (PD50)1 Sep 2021PD50-06 A COMPARISON OF MRI FUSION BIOPSY PI-RADS SCORING SYSTEM TO EXACTVU MICRO-ULTRASOUND PRI-MUS SCORING SYSTEM IN IDENTIFYING PROSTATE CANCER: A SINGLE INSTITUTION RETROSPECTIVE ANALYSIS Michael Hailemariam, Douglas Kelly, and Joshua Langston Michael HailemariamMichael Hailemariam More articles by this author , Douglas KellyDouglas Kelly More articles by this author , and Joshua LangstonJoshua Langston More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002072.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Multiparametric MRI in combination with ultrasound fusion technology is becoming standard in many urology practices. Advances in ultrasound technology with the high resolution (HiRes) ExactVuTM 29MHz micro-ultrasound system question the need for MRI with real time identification of lesions during ultrasound guided biopsy. This study seeks to compare the PI-RADs and PRI-MUS scoring systems associated with prostate MRI and HiRes ultrasound respectively. METHODS: This is a retrospective review of all men between the ages of 18-89 who underwent transrectal ultrasound guided biopsy of the prostate either with HiRes or MRI/ultrasound fusion using the UroNavR platform at our center during the period of January 1, 2006 through October 23, 2020. This study is comprised of 1236 subjects. 442 underwent HiRes ultrasound guided biopsy; and 797 underwent MRI/ultrasound fusion biopsy. All patients concomitantly underwent a standard 12 core biopsy. Data was collected including PI-RADs or PRI-MUS score, grade, and location of prostate cancer (region of interest vs standard template). Chi-squared test was performed to determine if PI-RADs 3, 4 and 5 lesions are equal to PRI-MUS 3, 4, and 5. RESULTS: With MRI fusion biopsy cancer was found at PIRADs 3, 4, and 5 ROIs in 31%, 59% and 78% of patients respectively. With HiRes ultrasound biopsy cancer was found at PRI-MUS 3, 4, and 5 ROIs in 18%, 40% and 54% of patients respectively. MRI-fusion biopsy found 16% more cancers than standard biopsy alone. High resolution biopsy found 5% more cancers than standard biopsy alone. Chi-squared analysis with alpha of 0.05 found that PI-RADS 3, 4, and 5 lesions and PRI-MUS 3, 4, and 5 lesions are not equal with regards to cancer yields. CONCLUSIONS: Our study found significant differences between PIRADs and PRI-MUS lesions and increased cancer detection with MRI-fusion biopsy vs HiRes biopsy. Multiple providers were involved in performing both types of biopsy and differences could be due to the subjective nature of HiRes biopsy. Both modalities increased cancer yield vs standard biopsy. More studies are needed to determine the role of MRI fusion vs HiRes biopsy; however, a combination of the two modalities holds significant potential. Source of Funding: None © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e853-e854 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Michael Hailemariam More articles by this author Douglas Kelly More articles by this author Joshua Langston More articles by this author Expand All Advertisement Loading ...

Predictive effect of DCE-MRI and DWI in brain metastases from NSCLC.

Non-small cell lung cancer (NSCLC), a commonly diagnosed lung cancer, is characterized by a high incidence of metastatic spread to the brain, which adversely impacts prognosis. The present study aimed to assess the value of combined dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) in predicting the treatment outcomes of whole-brain radiotherapy (WBRT) and gefitinib in brain metastases from non-small cell lung cancer (NSCLC) from the perspectives of response rate and short- and long-term efficacy. These results suggested that the indicators measured by DCE-MRI combined with DWI can be used as key imaging-derived markers that predicted the efficacy of WBRT combined with gefitinib in NSCLC patients with brain metastases. Specifically, patients with higher ΔADCmid and ΔADCpost values showed better treatment outcomes. ROC curve analysis indicated ADCpost, ΔADCpost, ΔADCpost (%), and tumor regression rate as the best predictors of efficacy of WBRT combined with gefitinib in these patients. The short-term and long-term effects noted were also significant. Taken together, the findings of this study reveal that tumor regression rate, ADCpost, ΔADCpost, and ΔADCpost (%) can be used as important imaging indicators that predict the therapeutic effect of WBRT combined with gefitinib in NSCLC patients with brain metastases.

Apparent diffusion coefficient echoplanar imaging maps of the optic nerves in childhood idiopathic intracranial hypertension.

Dueto motion artifacts, optic nerve (ON) findings of idiopathic intracranial hypertension (IIH) can easily be overlooked on T2-weighted (T2w) turbo spin-echo sequence. This study aimed to investigate the contribution of the apparent diffusion coefficient (ADC) map derived from the interleaved multi-shot (IMS) echoplanar imaging (EPI) to the ON findings of IIH in children. MRIs of 42 pediatric patients aged 3-17 years diagnosed with definite IIH according to modified Dandy criteria were retrospectively re-evaluated, between April 2018 and January 2021. Forty-two age- and sex-matched subjects with no IIH symptoms and reported as normal were included as a control group. ON sheath distance (ONSD) on the ADC map (p = .005) and vertical tortuosity (p = .030) were significant single MRI parameters for predicting IIH. Other single parameters were not statistically significant. Flattening of the posterior sclera (FPS) and ON protrusion (ONP) were observed on ADC maps more frequently than T2w (42.8% vs. 19% and 19% vs. 4.7%, respectively). From combined MRI parameters, the presence of at least one of ONP, FPS, or ONSD on ADC maps (p = .001) showed greater significance than the presence of T2w (p = .048). The predictive values of other MRI findings evaluated together were not statistically significant (p> .05). This study's results show that due to the short readout time and less sensitivity to motion, the ADC map obtained from IMS-EPI can contribute to orbital findings of IIH, in addition to T2w.

Spirometry-based reconstruction of real-time cardiac MRI: Motion control and quantification of heart-lung interactions.

To test the feasibility of cardiac real-time MRI in combination with retrospective gating by MR-compatible spirometry, to improve motion control, and to allow quantification of respiratory-induced changes during free-breathing. Cross-sectional real-time MRI (1.5T; 30 frames/s) using steady-state free precession contrast during free-breathing was combined with MR-compatible spirometry in healthy adult volunteers (n = 4). Retrospective binning assigned images to classes that were defined by electrocardiogram and spirometry. Left ventricular eccentricity index as an indicator of septal position and ventricular volumes in different respiratory phases were calculated to assess heart-lung interactions. Real-time MRI with MR-compatible spirometry is feasible and well tolerated. Spirometry-based binning improved motion control significantly. The end-diastolic epicardial eccentricity index increased significantly during inspiration (1.04 ± 0.04 to 1.19 ± 0.05; P < .05). During inspiration, right ventricular end-diastolic volume (79 ± 17 mL/m2 to 98 ± 18 mL/m2 ), stroke volume (41 ± 8 mL/m2 to 59 ± 11 mL/m2 ) and ejection fraction (53 ± 3% to 60 ± 1%) increased significantly, whereas the end-systolic volume remained almost unchanged. Left ventricular end-diastolic volume, left ventricular stroke volume, and left ventricular ejection fraction decreased during inspiration, whereas the left ventricular end-systolic volume increased. The relationship between stroke volume and end-diastolic volume (Frank-Starling relationship) based on changes induced by respiration allowed for a slope estimate of the Frank-Starling curve to be 0.9 to 1.1. Real-time MRI during free-breathing combined with MR-compatible spirometry and retrospective binning improves image stabilization, allows quantitative image analysis, and importantly, offers unique opportunities to judge heart-lung interactions.

Comparing different CT, PET and MRI multi-modality image combinations for deep learning-based head and neck tumor segmentation

Background Manual delineation of gross tumor volume (GTV) is essential for radiotherapy treatment planning, but it is time-consuming and suffers inter-observer variability (IOV). In clinics, CT, PET, and MRI are used to inform delineation accuracy due to their different complementary characteristics. This study aimed to investigate deep learning to assist GTV delineation in head and neck squamous cell carcinoma (HNSCC) by comparing various modality combinations. Materials and methods This retrospective study had 153 patients with multiple sites of HNSCC including their planning CT, PET, and MRI (T1-weighted and T2-weighted). Clinical delineations of gross tumor volume (GTV-T) and involved lymph nodes (GTV-N) were collected as the ground truth. The dataset was randomly divided into 92 patients for training, 31 for validation, and 30 for testing. We applied a residual 3 D UNet as the deep learning architecture. We independently trained the UNet with four different modality combinations (CT-PET-MRI, CT-MRI, CT-PET, and PET-MRI). Additionally, analogical to post-processing, an average fusion of three bi-modality combinations (CT-PET, CT-MRI, and PET-MRI) was produced as an ensemble. Segmentation accuracy was evaluated on the test set, using Dice similarity coefficient (Dice), Hausdorff Distance 95 percentile (HD95), and Mean Surface Distance (MSD). Results All imaging combinations including PET provided similar average scores in range of Dice: 0.72-0.74, HD95: 8.8-9.5 mm, MSD: 2.6-2.8 mm. Only CT-MRI had a lower score with Dice: 0.58, HD95: 12.9 mm, MSD: 3.7 mm. The average of three bi-modality combinations reached Dice: 0.74, HD95: 7.9 mm, MSD: 2.4 mm. Conclusion Multimodal deep learning-based auto segmentation of HNSCC GTV was demonstrated and inclusion of the PET image was shown to be crucial. Training on combined MRI, PET, and CT data provided limited improvements over CT-PET and PET-MRI. However, when combining three bimodal trained networks into an ensemble, promising improvements were shown.

Pulmonary Functional Imaging for Lung Adenocarcinoma: Combined MRI Assessment Based on IVIM-DWI and OE-UTE-MRI.

PurposeThe goal of current study was to introduce noninvasive and reproducible MRI methods for in vivo functional assessment of lung adenocarcinoma (LUAD).MethodsForty-four patients with pathologically confirmed LUAD were included in this study. All the lesions were classified as adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), or invasive adenocarcinoma (IA). The IA lesions were further divided into five subtype patterns, including acinar, lepidic, papillary, micropapillary and solid. Tumors were grouped depending on predominant subtype: low grade (AIS, MIA or lepidic predominant), intermediate grade (papillary or acinar predominant) and high grade (micropapillary, or solid predominant). Spirometry was performed according to American Thoracic Society guidelines. For each patient, Intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) analysis and oxygen-enhanced MRI (OE-MRI) analysis were performed. Spearman’s test was used to assess the relationship between a) whole lung mean percent signal enhancement (PSE) and pulmonary function tests (PFTs) parameters; b) IVIM-derived parameters and PFTs parameters; c) tumor mean PSE and IVIM-derived parameters. Kruskal -Wallis tests were applied to test the difference of tumor mean PSE and IVIM-derived parameters between different histological tumor grades. Receiver operating characteristics (ROC) analysis was used to evaluate the diagnostic performance.ResultsWhole lung mean PSE was significantly positively correlated with PFTs parameters (r = 0.40 ~ 0.44, P < 0.05). f value derived from IVIM-DWI was significantly negatively correlated with PFTs parameters (r = -0.38 ~ -0.47, P < 0.05). Both tumor mean PSE (P = 0.030 < 0.05) and f (P = 0.022 < 0.05) could differentiate different histological grades. f was negatively correlated with tumor mean PSE (r = -0.61, P < 0.001). For the diagnostic performance, the combination of tumor mean PSE and f outperformed than using tumor mean PSE or f alone in both sensitivity and area under the ROC curve.ConclusionsThe combined measurement of OE-MRI and IVIM-DWI may serve as a promising method for the noninvasive and non-radiation evaluation of pulmonary function. Quantitative analyses achieved by OE-MRI and IVIM-DWI offer an approach of the classification of LUAD subtypes.

Combining MRI and Histologic Imaging Features for Predicting Overall Survival in Patients with Glioma.

Purpose To test the hypothesis that combined features from MR and digital histopathologic images more accurately predict overall survival (OS) in patients with glioma compared with MRI or histopathologic features alone. Materials and Methods Multiparametric MR and histopathologic images in patients with a diagnosis of glioma (high- or low-grade glioma [HGG or LGG]) were obtained from The Cancer Imaging Archive (original images acquired 1983-2008). An extensive set of engineered features such as intensity, histogram, and texture were extracted from delineated tumor regions in MR and histopathologic images. Cox proportional hazard regression and support vector machine classification (SVC) models were applied to (a) MRI features only (MRIcox/svc), histopathologic features only (HistoPathcox/svc), and (c) combined MRI and histopathologic features (MRI+HistoPathcox/svc) and evaluated in a split train-test configuration. Results A total of 171 patients (mean age, 51 years ± 15; 91 men) were included with HGG (n = 75) and LGG (n = 96). Median OS was 467 days (range, 3-4752 days) for all patients, 350 days (range, 15-1561 days) for HGG, and 595 days (range, 3-4752 days) for LGG. The MRI+HistoPathcox model demonstrated higher concordance index (C-index) compared with MRIcox and HistoPathcox models on all patients (C-index, 0.79 vs 0.70 [P = .02; MRIcox] and 0.67 [P = .01; HistoPathcox]), patients with HGG (C-index, 0.78 vs 0.68 [P = .03; MRIcox] and 0.64 [P = .01; HistoPathcox]), and patients with LGG (C-index, 0.88 vs 0.62 [P = .008; MRIcox] and 0.62 [P = .006; HistoPathcox]). In binary classification, the MRI+HistoPathsvc model (area under the receiver operating characteristic curve [AUC], 0.86 [95% CI: 0.80, 0.95]) had higher performance than the MRIsvc model (AUC, 0.68 [95% CI: 0.50, 0.81]; P = .01) and the HistoPathsvc model (AUC, 0.72 [95% CI: 0.60, 0.85]; P = .04). Conclusion The model combining features from MR and histopathologic images had higher accuracy in predicting OS compared with the models with MR or histopathologic images alone. Keywords: Survival Prediction, Gliomas, Digital Pathology Imaging, MR Imaging, Machine Learning Supplemental material is available for this article.

Evaluation of a patient-specific algorithm for predicting distribution for convection-enhanced drug delivery into the brainstem of patients with diffuse intrinsic pontine glioma.

With increasing use of convection-enhanced delivery (CED) of drugs, the need for software that can predict infusion distribution has grown. In the context of a phase I clinical trial for pediatric diffuse intrinsic pontine glioma (DIPG), CED was used to administer an anti-B7H3 radiolabeled monoclonal antibody, iodine-124-labeled omburtamab. In this study, the authors retrospectively evaluated a software algorithm (iPlan Flow) for the estimation of infusate distribution based on the planned catheter trajectory, infusion parameters, and patient-specific MRI. The actual infusate distribution, as determined on MRI and PET imaging, was compared to the distribution estimated by the software algorithm. Similarity metrics were used to quantify the agreement between predicted and actual distributions. Ten pediatric patients treated at the same dose level in the NCT01502917 trial conducted at Memorial Sloan Kettering Cancer Center were considered for this retrospective analysis. T2-weighted MRI in combination with PET imaging was used to determine the distribution of infusate in this study. The software algorithm was applied for the generation of estimated fluid distribution maps. Similarity measures included object volumes, intersection volume, union volume, Dice coefficient, volume difference, and the center and average surface distances. Acceptable similarity was defined as a simulated distribution volume (Vd Sim) object that had a Dice coefficient higher than or equal to 0.7, a false-negative rate (FNR) lower than 50%, and a positive predictive value (PPV) higher than 50% compared to the actual Vd (Vd PET). Data for 10 patients with a mean infusion volume of 4.29 ml (range 3.84-4.48 ml) were available for software evaluation. The mean Vd Sim found to be covered by the actual PET distribution (PPV) was 77% ± 8%. The mean percentage of PET volume found to be outside the simulated volume (FNR) was 34% ± 10%. The mean Dice coefficient was 0.7 ± 0.05. In 8 out of 10 patients, the simulation algorithm fulfilled the combined acceptance criteria for similarity. iPlan Flow software can be useful to support planning of trajectories that produce intraparenchymal convection. The simulation algorithm is able to model the likely infusate distribution for a CED treatment in DIPG patients. The combination of trajectory planning guidelines and infusion simulation in the software can be used prospectively to optimize personalized CED treatment.

High-speed fluoroscopic imaging for investigation of three-dimensional knee kinematics before and after marathon running.

Knee injuries often occur during or shortly after marathon running, and are linked to altered knee kinematics. The kinematics of healthy knees during pre- and post-marathon running have not been examined with high-speed fluoroscopy. This study aimed to evaluate the effects of marathon running on knee kinematics during walking and running by using a combined high-speed fluoroscopy and MRI technique. Ten healthy runners underwent knee MRI within 24 h before marathon running to construct three-dimensional (3D) knee models. Knee kinematics during treadmill walking and running were evaluated using high-speed fluoroscopy (200hz) within 24 h before and as soon as possible (within 5 h) after marathon running. All pre- and post-marathon measurements were compared. (1) For post-marathon walking, posterior femoral translation increased 1.4 mm at initial contact (p = 0.015); proximal-distal distance of tibia and femur decreased 0.7 mm and 0.8 mm at initial contact and after contact, respectively (p = 0.039, p = 0.046); and valgus femur rotation increased 1.2° after contact (p = 0.027). (2) For post-marathon running, proximal-distal distance decreased 0.7 mm and 1.0 mm at initial contact and after contact (p = 0.011, p = 0.003) respectively; knee flexion decreased 4.3° before contact (p = 0.007); knee flexion increased 1.8° and 2.6° at initial contact and after contact, respectively (p = 0.038, p = 0.011); external femoral rotation increased 1.2° and 1.8° at initial contact and after contact, respectively (p = 0.012, p = 0.037). Valgus femoral rotation after contact increased 2.3° (p = 0.001). Post-marathon changes in valgus and external femoral rotation, knee flexion, posterior femoral translation, and proximal-distal distance may increase the risk of knee injury. This study provides information to better understand the response of the knee to marathon running.

Altered sensorimotor integration in multiple sclerosis: A combined neurophysiological and functional MRI study

ObjectiveTo explore whether abnormal thalamic resting-state functional connectivity (rsFC) contributes to altered sensorimotor integration and hand dexterity impairment in multiple sclerosis (MS). MethodsTo evaluate sensorimotor integration, we recorded kinematic features of index finger abductions during somatosensory temporal discrimination threshold (STDT) testing in 36 patients with relapsing-remitting MS and 39 healthy controls (HC). Participants underwent a multimodal 3T structural and functional MRI protocol. ResultsPatients had lower index finger abduction velocity during STDT testing compared to HC. Thalamic rsFC with the precentral and postcentral gyri, supplementary motor area (SMA), insula, and basal ganglia was higher in patients than HC. Intrathalamic rsFC and thalamic rsFC with caudate and insula bilaterally was lower in patients than HC. Finger movement velocity positively correlated with intrathalamic rsFC and negatively correlated with thalamic rsFC with the precentral and postcentral gyri, SMA, and putamen. ConclusionsAbnormal thalamic rsFC is a possible substrate for altered sensorimotor integration in MS, with high intrathalamic rsFC facilitating finger movements and increased thalamic rsFC with the basal ganglia and sensorimotor cortex contributing to motor performance deterioration. SignificanceThe combined study of thalamic functional connectivity and upper limb sensorimotor integration may be useful in identifying patients who can benefit from early rehabilitation to prevent upper limb motor impairment.

Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging.

Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow induced by a change in a vasoactive stimulus. CVR using BOLD MRI in combination with changes in end-tidal CO2 is a very useful method for assessing vascular performance. In recent years, this technique has benefited from an advanced gas delivery method where end-tidal CO2 can be targeted, measured very precisely, and validated against arterial blood gas sampling (Ito et al., 2008). This has enabled more precise comparison of an individual patient against a normative atlas of healthy subjects. However, expected control ranges for CVR metrics have not been reported in the literature. In this work, we calculate and report the range of control values for the magnitude (mCVR), the steady state amplitude (ssCVR), and the speed (TAU) of the BOLD response to a standard step stimulus, as well as the time delay (TD) as observed in a cohort of 45 healthy controls. These CVR metrics maps were corrected for partial volume averaging for brain tissue types using a linear regression method to enable more accurate quantitation of CVR metrics. In brief, this method uses adjacent voxel CVR metrics in combination with their tissue composition to write the corresponding set of linear equations for estimating CVR metrics of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). After partial volume correction, mCVR and ssCVR increase as expected in gray matter, respectively, by 25 and 19%, and decrease as expected in white matter by 33 and 13%. In contrast, TAU and TD decrease in gray matter by 33 and 13%. TAU increase in white matter by 24%, but TD surprisingly decreased by 9%. This correction enables more accurate voxel-wise tissue composition providing greater precision when reporting gray and white matter CVR values.

Longitudinal structural and perfusion MRI enhanced by machine learning outperforms standalone modalities and radiological expertise in high-grade glioma surveillance

PurposeSurveillance of patients with high-grade glioma (HGG) and identification of disease progression remain a major challenge in neurooncology. This study aimed to develop a support vector machine (SVM) classifier, employing combined longitudinal structural and perfusion MRI studies, to classify between stable disease, pseudoprogression and progressive disease (3-class problem).MethodsStudy participants were separated into two groups: group I (total cohort: 64 patients) with a single DSC time point and group II (19 patients) with longitudinal DSC time points (2-3). We retrospectively analysed 269 structural MRI and 92 dynamic susceptibility contrast perfusion (DSC) MRI scans. The SVM classifier was trained using all available MRI studies for each group. Classification accuracy was assessed for different feature dataset and time point combinations and compared to radiologists’ classifications.ResultsSVM classification based on combined perfusion and structural features outperformed radiologists’ classification across all groups. For the identification of progressive disease, use of combined features and longitudinal DSC time points improved classification performance (lowest error rate 1.6%). Optimal performance was observed in group II (multiple time points) with SVM sensitivity/specificity/accuracy of 100/91.67/94.7% (first time point analysis) and 85.71/100/94.7% (longitudinal analysis), compared to 60/78/68% and 70/90/84.2% for the respective radiologist classifications. In group I (single time point), the SVM classifier also outperformed radiologists’ classifications with sensitivity/specificity/accuracy of 86.49/75.00/81.53% (SVM) compared to 75.7/68.9/73.84% (radiologists).ConclusionOur results indicate that utilisation of a machine learning (SVM) classifier based on analysis of longitudinal perfusion time points and combined structural and perfusion features significantly enhances classification outcome (p value= 0.0001).

Physiological articular contact kinematics and morphological femoral condyle translations of the tibiofemoral joint

The changes of tibiofemoral articular cartilage contact locations during knee activities represent a physiological functional characteristic of the knee. However, most studies reported relative motions of the tibia and femur using morphological flexion axes. Few data have been reported on comparisons of morphological femoral condyle motions and physiological tibiofemoral cartilage contact location changes. This study compared the morphological and physiological kinematic measures of 20 knees during an in vivo weightbearing single leg lunge from full extension to 120° of flexion using a combined MRI and dual fluoroscopic imaging system (DFIS) technique. The morphological femoral condyle motion was measured using three flexion axes: trans-epicondylar axis (TEA), geometric center axis (GCA) and iso-height axis (IHA). At low flexion angles, the medial femoral condyle moved anteriorly, opposite to that of the contact points, and was accompanied with a sharp increase in external femoral condyle rotation. At 120° of flexion, the morphological measures of the lateral femoral condyle were more posteriorly positioned than those of the contact locations. The data showed that the morphological measures of femoral condyle translations and axial rotations varied with different flexion axes and did not represent the physiological articular contact kinematics. Biomechanical evaluations of the knee joint motion should include both morphological and physiological kinematics data to accurately demonstrate the functionality of the knee.

Added Value of MRI for Invasive Breast Cancer including the Entire Axilla for Evaluation of High-Level or Advanced Axillary Lymph Node Metastasis in the Post–ACOSOG Z0011 Trial Era

Background In the post-American College of Surgeons Oncology Group Z0011 trial era, radiologists have increasingly focused on excluding high-level or advanced axillary lymph node metastasis (ALNM) by using an additional MRI scan positioned higher than lower axillae; however, the value of these additional scans remains undetermined. Purpose To evaluate whether a standard MRI protocol is sufficient to exclude high-level or advanced ALNM in breast cancer or additional MRI of entire axilla is needed. Materials and Methods This retrospective study evaluated women with invasive breast cancer who underwent breast MRI from April 2015 to December 2016. Some underwent neoadjuvant chemotherapy (NAC) and others underwent upfront surgery. Standard (routine axial scans including the lower axillae) and combined (routine axial scans plus additional scans including the entire axilla) MRI protocols were compared for high-level or advanced ALNM detection. Clinical-pathologic characteristics were analyzed. Uni- and multivariable logistic regression was performed to identify predictors of high-level or advanced ALNM. Results A total of 435 women (mean age ± standard deviation, 52 years ± 11) were evaluated (65 in the NAC group, 370 in the non-NAC group). With the standard MRI protocol, predictors of high-level ALNM were peritumoral edema (odds ratio [OR], 12.3; 95% CI: 3.9, 39.4; P < .001) and positive axilla (OR, 5.9; 95% CI: 2.0, 15.2; P < .001). Only three of 289 women with negative axillae without peritumoral edema had high-level ALNM. Predictors of advanced ALNM were positive axillae (OR, 8.9; 95% CI: 3.7, 21.5; P < .001) and peritumoral edema (OR, 2.8; 95% CI: 1.1, 6.9; P = .03). Only six of 310 women who had negative axillae without peritumoral edema had advanced ALNM. Conclusion The performance of standard MRI was satisfactory in excluding high-level and advanced axillary lymph node metastasis in most patients with breast cancer. However, the presence of peritumoral edema or positive axillae in the MRI findings emphasizes the benefits of a combined MRI protocol. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Abe in this issue.

Cerebral grey matter density is associated with neuroreceptor and neurotransporter availability: A combined PET and MRI study

Positron emission tomography (PET) can be used for in vivo measurement of specific neuroreceptors and transporters using radioligands, while voxel-based morphometric analysis of magnetic resonance images allows automated estimation of local grey matter densities. However, it is not known how regional neuroreceptor or transporter densities are reflected in grey matter densities. Here, we analyzed brain scans retrospectively from 328 subjects and compared grey matter density estimates with neuroreceptor and transporter availabilities. µ-opioid receptors (MORs) were measured with [11C]carfentanil (162 scans), dopamine D2 receptors with [11C]raclopride (92 scans) and serotonin transporters (SERT) with [11C]MADAM (74 scans). The PET data were modelled with simplified reference tissue model. Voxel-wise correlations between binding potential and grey matter density images were computed. Regional binding of all the used radiotracers was associated with grey matter density in region and ligand-specific manner independently of subjects’ age or sex. These data show that grey matter density and MOR and D2R neuroreceptor / SERT availability are correlated, with effect sizes (r2) ranging from 0.04 to 0.69. This suggests that future studies comparing PET outcome measure different groups (such as patients and controls) should also analyze interactive effects of grey matter density and PET outcome measures.

Diffuse axonal injury has a characteristic multidimensional MRI signature in the human brain.

Axonal injury is a major contributor to the clinical symptomatology in patients with traumatic brain injury. Conventional neuroradiological tools, such as CT and MRI, are insensitive to diffuse axonal injury (DAI) caused by trauma. Diffusion tensor MRI parameters may change in DAI lesions; however, the nature of these changes is inconsistent. Multidimensional MRI is an emerging approach that combines T1, T2, and diffusion, and replaces voxel-averaged values with distributions, which allows selective isolation of specific potential abnormal components. By performing a combined post-mortem multidimensional MRI and histopathology study, we aimed to investigate T1-T2-diffusion changes linked to DAI and to define their histopathological correlates. Corpora callosa derived from eight subjects who had sustained traumatic brain injury, and three control brain donors underwent post-mortem ex vivo MRI at 7 T. Multidimensional, diffusion tensor, and quantitative T1 and T2 MRI data were acquired and processed. Following MRI acquisition, slices from the same tissue were tested for amyloid precursor protein (APP) immunoreactivity to define DAI severity. A robust image co-registration method was applied to accurately match MRI-derived parameters and histopathology, after which 12 regions of interest per tissue block were selected based on APP density, but blind to MRI. We identified abnormal multidimensional T1-T2, diffusion-T2, and diffusion-T1 components that are strongly associated with DAI and used them to generate axonal injury images. We found that compared to control white matter, mild and severe DAI lesions contained significantly larger abnormal T1-T2 component (P = 0.005 and P < 0.001, respectively), and significantly larger abnormal diffusion-T2 component (P = 0.005 and P < 0.001, respectively). Furthermore, within patients with traumatic brain injury the multidimensional MRI biomarkers differentiated normal-appearing white matter from mild and severe DAI lesions, with significantly larger abnormal T1-T2 and diffusion-T2 components (P = 0.003 and P < 0.001, respectively, for T1-T2; P = 0.022 and P < 0.001, respectively, for diffusion-T2). Conversely, none of the conventional quantitative MRI parameters were able to differentiate lesions and normal-appearing white matter. Lastly, we found that the abnormal T1-T2, diffusion-T1, and diffusion-T2 components and their axonal damage images were strongly correlated with quantitative APP staining (r = 0.876, P < 0.001; r = 0.727, P < 0.001; and r = 0.743, P < 0.001, respectively), while producing negligible intensities in grey matter and in normal-appearing white matter. These results suggest that multidimensional MRI may provide non-invasive biomarkers for detection of DAI, which is the pathological substrate for neurological disorders ranging from concussion to severe traumatic brain injury.

Considerations for active surveillance in select Gleason grade group 2 patients: A preliminary study.

206 Background: While active surveillance (AS) has become the preferred management strategy for patients with NCCN very-low and low risk prostate cancer, its use in the setting of intermediate risk disease continues to be controversial. Current guidelines state that AS can be considered in favorable intermediate risk disease, but data on outcomes in this cohort of patients is lacking. We aim to report on our experience with AS of Gleason grade group (GG) 2 at the National Cancer Institute (NCI)/National Institutes of Health (NIH). Methods: Our IRB-approved, institutional database was reviewed for men who enrolled on our AS protocol at NIH with GG2 disease from 2007-2020. All patients received MRI-targeted and systematic biopsy at the time of enrollment, diagnosing or confirming GG2 disease. MRI and PSA were performed annually, and majority of patients underwent annual combined MRI targeted and systematic prostate biopsy. If PSA and MRI were stable, annual biopsy was postponed in several patients based on their preference. Differences in PSA and PSAD at enrollment on AS and at progression were compared using Wilcoxon signed rank test. P value &lt; 0.05 was considered significant. Results: 98 patients with GG2 disease enrolled in AS at NIH. Average age at enrollment was 64 years old and the majority of patients were Caucasian. 36/98(37%) of these patients progressed to GG3 or higher while on AS. Median PSA at time of progression was significantly higher than at the time of enrollment on AS (5.2 [IQR 4.0-8.9] vs 8.5 [IQR 5.8-10.9], z = -3.12, p &lt; 0.01). PSAD was also significantly higher at time of progression (0.12[IQR 0.1-0.16] vs 0.13[IQR 0.10-0.22], z = -2.65, p &lt; 0.01). Highest PIRADS score on MRI was largely unchanged. Median time to progression was 71 months. The majority of patients progressed to GG3, and progression was the trigger for definitive treatment. All patients were alive at the end of the follow up period. Conclusions: AS is a reasonable option for compliant patients diagnosed with GG2 prostate cancer. While a significant percentage of these men will progress on AS, they do so at a median of 71 months, avoiding treatment-related harms of definitive therapy for over 5 years. Further research with larger sample sizes are needed to better evaluate the oncologic outcomes of AS for GG2 disease, as well as predictors of more aggressive disease that may be better served with upfront definitive treatment. [Table: see text]

Abstract PS1-19: The accuracy of axillary node assessment of ultrasound after neoadjuvant chemotherapy in clinically node positive patients

Abstract Background. Neo-adjuvant chemotherapy (NAC) is widely used as preoperative systemic therapy for operable breast cancer. However, the use of sentinel-lymph-node biopsy (SNB) following NAC for patients with clinically node positive is controversial, even if they achieve cCR in the axilla. Although preoperative axillary imaging assessment may help to decide axillary management after NAC, few data are available on whether axillary ultrasound (LN-US) is useful to assess axillary response to NAC. Purpose. We investigated the accuracy of axillary node assessment by ultrasound after NAC in clinically node positive patients and analyzed factors related to the accuracy of LN-US. Methods. From January 2012 through December 2016, patients with cT1-4, N1-2, M0 primary breast cancer who had cytologically proven axillary metastasis, and underwent axillary lymph node dissection (ALND) after NAC were retrospectively reviewed. Clinically positive lymph node by LN-US was defined as concentric cortical thickness &amp;gt;3mm, absent fatty hilum, or irregular morphology. Results. A total of 298 patients with clinical stage T1-4, N1-2, M0 primary breast cancer who had cytologically proven axillary metastasis, and underwent surgery with axillary dissection following NAC were enrolled. Of 279 eligible patients, 101 patients (36.2%) showed pathologically node-negative in the axilla (ypN0), and the rate of ypN0 was 20.2% (37/183) in hormone receptor (HR)+/human epidermal growth factor receptor-2 (HER2)-, 71.9% (23/32) in HR+/HER2+, 83.3% (20/24) in HR-/HER2+, and 52.5% (21/40) in HR-/HER2-. Sensitivity and specificity of LN-US were 65.7% and 62.3% respectively. The accurate prediction rate of node-negative status after NAC by LN-US was 49.2% in total, 29.7% in HR+/HER2-, 89.5% in HR+/HER2+, 86.7% in HR-/HER2+, and 68.8% in HR-/HER2- disease. The accuracy was highest in the HER2+, and lowest in HR+/HER2-. The median number of pathologically positive residual nodes at ALND after NAC was 2 (1-16) in total and 2 (1-15) in patients with ycN0. Of 61 patients with ycN0ypN+, 26 (42.6%) had 1 positive lymph node on the pathologic review, 9 (14.8%) had 2 positive lymph nodes, 7 (11.5%) had 3 positive lymph nodes, and 19 (31.1%) had more than 3 positive lymph nodes.The accuracy of node negative status by LN-US varies significantly by tumor subtype (p&amp;lt;0.001) and tumor response as assessed by MRI after completion of NAC (p=0.0003), although there was no significant difference between two groups regarding T category at diagnosis, tumor histology, and the number of positive nodes before NAC as assessed by LN-US. Of 23 patients who achieved ycN0 in LN-US and cCR in the primary lesion in MRI, the accurate prediction rate of ypN0 was 100% in patients with HR±/HER2+ and HR-/HER2- disease. Conclusion. The accuracy of axillary US after NAC depended on subtypes, which was highest in the HER2 disease and the accuracy increased by combing with the tumor response in the breast assessed by MRI. In the point of reducing FNR after NAC by LN-US assessment before surgery, the accuracy of NPV is especially important. We suggest that it is of clinical importance to take account of tumor subtypes and primary tumor response in the breast by MRI in combination with LN-US in selecting patients for SNB after NAC. Citation Format: Yurina Maeshima, Takehiko Sakai, Akiko Ogiya, Yoko Takahashi, Yumi Miyagi, Takayuki Ueno, Shinji Ohno. The accuracy of axillary node assessment of ultrasound after neoadjuvant chemotherapy in clinically node positive patients [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-19.

Direct Structural Connections between Auditory and Visual Motion-Selective Regions in Humans.

In humans, the occipital middle-temporal region (hMT+/V5) specializes in the processing of visual motion, while the planum temporale (hPT) specializes in auditory motion processing. It has been hypothesized that these regions might communicate directly to achieve fast and optimal exchange of multisensory motion information. Here we investigated, for the first time in humans (male and female), the presence of direct white matter connections between visual and auditory motion-selective regions using a combined fMRI and diffusion MRI approach. We found evidence supporting the potential existence of direct white matter connections between individually and functionally defined hMT+/V5 and hPT. We show that projections between hMT+/V5 and hPT do not overlap with large white matter bundles, such as the inferior longitudinal fasciculus and the inferior frontal occipital fasciculus. Moreover, we did not find evidence suggesting the presence of projections between the fusiform face area and hPT, supporting the functional specificity of hMT+/V5-hPT connections. Finally, the potential presence of hMT+/V5-hPT connections was corroborated in a large sample of participants (n = 114) from the human connectome project. Together, this study provides a first indication for potential direct occipitotemporal projections between hMT+/V5 and hPT, which may support the exchange of motion information between functionally specialized auditory and visual regions.SIGNIFICANCE STATEMENT Perceiving and integrating moving signal across the senses is arguably one of the most important perceptual skills for the survival of living organisms. In order to create a unified representation of movement, the brain must therefore integrate motion information from separate senses. Our study provides support for the potential existence of direct connections between motion-selective regions in the occipital/visual (hMT+/V5) and temporal/auditory (hPT) cortices in humans. This connection could represent the structural scaffolding for the rapid and optimal exchange and integration of multisensory motion information. These findings suggest the existence of computationally specific pathways that allow information flow between areas that share a similar computational goal.