T2W Sequences Research Articles

Diagnostic utility of contrast-enhanced FLAIR MRI in imaging of demyelinating and infectious brain lesions

BackgroundContrast-enhanced MRI is frequently used as a baseline modality and indispensable tool for early diagnosis and follow-up of different brain lesions. Herein, we aimed to evaluate the diagnostic impact of contrast-enhanced FLAIR compared to the widely used post-contrast T1W sequence in terms of demyelinating and infectious brain lesions detection in clinical practice and explore its value in monitoring disease activity for selecting appropriate therapy. MR Imaging was performed using 1.5 Tesla device. Both T1W and FLAIR sequences were obtained prior to and after administration of intravenous gadolinium-based contrast agent. Both qualitative and quantitative approaches were used for image analysis by two independent radiologists.ResultsSixty patients were prospectively enrolled in this study. Our participants were subdivided into two categories, either demyelinating (45 multiple sclerosis) or infectious lesions (13 meningitis/meningoencephalitis and 2 pyogenic abscess). By comparing the two post-contrast sequences, CE-FLAIR revealed greater enhancement in 38 cases (63.34%), equal enhancement in 17 cases (28.33%) and less enhancement in 5 cases (8.33%). For lesion conspicuity: good delineation observed in (61.67%), fair delineation in (25%) and no delineation in (13.33%). Lesion-to-background contrast ratio was statistically significant in CE-FLAIR with excellent inter-class correlation.ConclusionCE-FLAIR should be added in conjunction with or as a superior alternative to conventional CE-T1W sequence to optimize lesion detection and improve diagnostic reliability particularly in demyelinating and infectious lesions.

Role of abbreviated non-contrast-enhanced MR-enterography in the evaluation of Crohn's disease activity and complications as an alternative for full protocol contrast-enhanced study: A systematic review and meta-analysis.

Crohn's disease (CD) is a chronic disorder that often starts at a young age and involves periods of remission and relapse. Prompt diagnosis of relapses through screening is crucial due to the potential morbid complications of untreated active inflammation. Magnetic resonance enterography (MRE) is a noninvasive technique to screen for active inflammation. The standard protocol involves intravenous injection of contrast agents with potential side effects. Some abbreviated non-contrast-enhanced MRE protocols are proposed as alternatives for conventional MRE to identify active inflammation. Currently, there is controversy regarding the applicability and accuracy of these protocols. This study aims to describe and compare these protocols and evaluate their accuracy in detecting active inflammation and CD complications. Results from a systematic search of three databases in August 2022 were queried and screened by abstract and full text. Eligible studies were qualitatively and quantitatively analyzed by diagnostic test accuracy meta-analysis. 59 studies entered the systematic review, and 37 were eligible for meta-analysis. Diffusion-weighted imaging (DWI) and fast T2-weighted (T2w) sequences were most frequently used in abbreviated protocols and showed non-inferior accuracy compared to the full protocol in detecting active inflammation. ADC and qualitative DWI had pooled sensitivity of 90% (CI: 82-95%) and 89% (CI:82-93%) and pooled specificity of 94% (CI: 88-97%) and 89% (CI: 79-94%), respectively for detecting active inflammation. Moreover, T2w and combined T2w+DWI sequences had pooled sensitivity of 80% (CI: 64-90%) and 76% (CI: 61-86%) and pooled specificity of 90% (CI: 80-95%) and 87% (CI: 74 - 94%), respectively. Unenhanced protocols show relatively poor diagnostic accuracy in detecting penetrating complications of CD. Magnetization transfer imaging (MTI) has demonstrated excellent accuracy in detecting fibrosis. High heterogeneity was observed in all subgroups, and accuracy was reported to be highly operator dependent in most studies. An abbreviated protocol consisting of DWI and fast T2w imaging can potentially replace the full protocol MRE. Full protocol MRE will still have its role in identifying penetrating complications. MTI should be indicated in case of suspected fibrostenotic disease.

Prediction of prostate tumour hypoxia using pre-treatment MRI-derived radiomics: preliminary findings

PurposeTo develop a machine learning (ML) model based on radiomic features (RF) extracted from whole prostate gland magnetic resonance imaging (MRI) for prediction of tumour hypoxia pre-radiotherapy.Material and methodsConsecutive patients with high-grade prostate cancer and pre-treatment MRI treated with radiotherapy between 01/12/2007 and 1/08/2013 at two cancer centres were included. Cancers were dichotomised as normoxic or hypoxic using a biopsy-based 32-gene hypoxia signature (Ragnum signature). Prostate segmentation was performed on axial T2-weighted (T2w) sequences using RayStation (v9.1). Histogram standardisation was applied prior to RF extraction. PyRadiomics (v3.0.1) was used to extract RFs for analysis. The cohort was split 80:20 into training and test sets. Six different ML classifiers for distinguishing hypoxia were trained and tuned using five different feature selection models and fivefold cross-validation with 20 repeats. The model with the highest mean validation area under the curve (AUC) receiver operating characteristic (ROC) curve was tested on the unseen set, and AUCs were compared via DeLong test with 95% confidence interval (CI).Results195 patients were included with 97 (49.7%) having hypoxic tumours. The hypoxia prediction model with best performance was derived using ridge regression and had a test AUC of 0.69 (95% CI: 0.14). The test AUC for the clinical-only model was lower (0.57), but this was not statistically significant (p = 0.35). The five selected RFs included textural and wavelet-transformed features.ConclusionWhole prostate MRI-radiomics has the potential to non-invasively predict tumour hypoxia prior to radiotherapy which may be helpful for individualised treatment optimisation.

Association of pre-radiotherapy tumour burden and overall survival in newly diagnosed glioblastoma adjusted for MGMT promoter methylation status

PurposeWe retrospectively evaluated the association between postoperative pre-radiotherapy tumour burden and overall survival (OS) adjusted for the prognostic value of O6-methylguanine DNA methyltransferase (MGMT) promoter methylation in patients with newly diagnosed glioblastoma treated with radio-/chemotherapy with temozolomide. Materials and methodsPatients were included from the CENTRIC (EORTC 26071-22072) and CORE trials if postoperative magnetic resonance imaging scans were available within a timeframe of up to 4weeks before radiotherapy, including both pre- and post-contrast T1w images and at least one T2w sequence (T2w or T2w-FLAIR). Postoperative (residual) pre-radiotherapy contrast-enhanced tumour (CET) volumes and non-enhanced T2w abnormalities (NT2A) tissue volumes were obtained by three-dimensional segmentation. Cox proportional hazard models and Kaplan Meier estimates were used to assess the association of pre-radiotherapy CET/NT2A volume with OS adjusted for known prognostic factors (age, performance status, MGMT status). Results408 tumour (of which 270 MGMT methylated) segmentations were included. Median OS in patients with MGMT methylated tumours was 117 weeks versus 61weeks in MGMT unmethylated tumours (p < 0.001). When stratified for MGMT methylation status, higher CET volume (HR 1.020; 95% confidence interval CI [1.013–1.027]; p < 0.001) and older age (HR 1.664; 95% CI [1.214–2.281]; p = 0.002) were significantly associated with shorter OS while NT2A volume and performance status were not. ConclusionPre-radiotherapy CET volume was strongly associated with OS in patients receiving radio-/chemotherapy for newly diagnosed glioblastoma stratified by MGMT promoter methylation status.

Radiological Profile of Patients with Wilson’s Disease Attending Tertiary Care Neurology Centre (P13-11.009)

<h3>Objective:</h3> To assess the radiological profile of patients with Wilson’s disease attending a tertiary care neurology center. <h3>Background:</h3> Wilson’s disease (WD) is an autosomal recessive disorder with varied manifestations, resulting from the deposition of copper in organs such as the brain, liver and cornea. This study was aimed at assessing the radiological profile of patients with WD. <h3>Design/Methods:</h3> This study was conducted at the Neurology department of a tertiary care centre. Patients with diagnosed WD (modified Leipzig score 3 or more) underwent 3 Tesla MRI brain with T1W, T2W, FLAIR, diffusion weighted and susceptibility weighted (SWI) sequences. <h3>Results:</h3> Between June 2021 and September 2022, twenty patients (15 males) of WD had brain MRI. Median age of cohort was 21 years (IQR 16–23). The mean duration of the illness was 5 years (range: 2–17) and 90% (18/20) were receiving chelation therapy at the time of imaging. The most common neurological manifestation was dystonia, seen in all the patients. Tremor was seen in 35% (7/20) and ataxia in 30% (6/20) of patients. The most common radiological finding was the hyperintensity of brainstem structures in T2W and FLAIR sequences, seen in 18/20 (90%) patients, followed by basal ganglia (BG) involvement. Putamen (17/20, 85%) was the most common BG structure involved, followed by the caudate nucleus (14/20, 70%). Thalamic involvement was seen in 12/20 (60%) of cases. SWI revealed blooming, most commonly in substantia nigra (12/20, 60%), followed by the globus pallidus (11/20, 55%), and caudate nucleus (7/20, 35%). Cerebellar and cerebral atrophy were seen in 14/20 (70%) and 9/20 (45%) patients, respectively. <h3>Conclusions:</h3> Brainstem involvement was seen most common radiological finding in our cohort, followed by the basal ganglia (putamen) involvement. Findings from our study need to be validated in larger studies and correlated with clinical features, stage of the disease and treatment status. <b>Disclosure:</b> Ms. Aliyar has nothing to disclose. Dr. Radhakrishnan has received research support from Indian Council of Medical Research, New Delhi, India. Dr. Radhakrishnan has received research support from World Federation of Neurology . Ajay Garg has nothing to disclose. Dr. Srivastava has nothing to disclose. Roopa Rajan has received research support from DBT. Roopa Rajan has received research support from DST-SERB. The institution of Roopa Rajan has received research support from Michael J Fox Foundaton. Awadh K. Pandit has nothing to disclose. Dr. Das has nothing to disclose. Dr. Agarwal has nothing to disclose.

Optimization of workflow for detection of brain metastases at 3T: is a black-blood MTC prepared 3D T1 used alone robust enough to replace the combination of conventional 3D T1 and the black-blood 3D T1 MTC?

PurposeSampling perfection with application-optimized contrasts by using different flip angle evolutions (SPACE) is a black-blood 3D T1-weighted (T1w) magnetic resonance imaging (MRI) sequence that has shown robust performance for brain metastases detection. However, this could generate false positive results due to suboptimal blood signal suppression. For that reason, SPACE is used in our institution alongside a non-black-blood T1w sequence: volumetric interpolated breath-hold examination (VIBE). Our study aims to (i) evaluate the diagnostic accuracy of SPACE compared to its use in combination with VIBE, (ii) investigate the effect of radiologist’s experience in the sequence’s performance, and (iii) analyze causes of discordants results.MethodsFour hundred seventy-three 3T MRI scans were retrospectively analyzed following a monocentric study design. Two studies were formed: one including SPACE alone and one combining both sequences (SPACE + VIBE, the reference). An experienced neuroradiologist and a radiology trainee independently reviewed the images of each study and reported the number of brain metastases. The sensitivity (Se) and specificity (Sp) of SPACE compared to SPACE + VIBE in metastases detection were reported. Diagnostic accuracy of SPACE compared to SPACE + VIBE was assessed by using McNemar’s test. Significance was set at p < 0.05. Cohen’s kappa was used for inter-method and inter-observer variability.ResultsNo significant difference was found between the two methods, with SPACE having a Se > 93% and a Sp > 87%. No effect of readers’ experience was disclosed.ConclusionIndependently of radiologist’s experience, SPACE alone is robust enough to replace SPACE + VIBE for brain metastases detection.

Susceptibility weighted imaging can be a sensitive sequence to detect brain damage in neonates with kernicterus: a case report

BackgroundKernicterus in the acute phase is difficult to diagnose. It depends on a high signal on T1 at the globus pallidum and subthalamic nucleus level. Unfortunately, these areas also show a relatively high signal on T1 in neonates as an expression of early myelination. Therefore, a less myelin-dependent sequence, like SWI, may be more sensitive to detecting damage in the globus pallidum area.Case presentationA term baby developed jaundice on day three following an uncomplicated pregnancy and delivery. Total bilirubin peaked at 542 μmol/L on day four. Phototherapy was started, and an exchange transfusion was performed. ABR showed absent responses on day 10. MRI on day eight demonstrated abnormal high signal globus pallidus on T1w, isointense on T2w, without diffusion restriction, and high signal on SWI at globus pallidal and subthalamus level and phase image at globus pallidal level. These findings were consistent with the challenging diagnosis of kernicterus. On follow-up, the infant presented with sensorineural hearing loss and had a work-up for cochlear implant surgery. At 3 months of age, the follow-up MR shows normalization of the T1 and SWI signals and a high signal on T2.ConclusionsSWI seems more sensitive to injury than the T1w and lacks the disadvantage of the T1w sequence, where early myelin confers a high signal.

Diagnostic Accuracy and Agreement between Magnetic Resonance Imaging and Ultrasound Finding for the Diagnosis of Rotator Cuff Tears

Objective: To determine the diagnostic accuracy and agreement between ultrasound and magnetic resonance (MR) imaging in determining rotator cuff tears.&#x0D; Study Design: Cross-sectional study.&#x0D; Place and Duration of the Study: Armed Forces Institute of Radiology and Imaging, Pak Emirates Military Hospital,Rawalpindi Pakistan, from Jul 2018 to Jan 2019.&#x0D; Methodology: Patients of either gender with a traumatic shoulder injury duration of less than 15 days were consecutively included. Rotator cuff tear on ultrasonography was diagnosed on the presence of a hypoechoic discontinuity in the tendon and accentuation of cartilage shadow, giving a 'double cortex' view while on MRI, the hyper-intense signal area within the tendon on T2W, fat-suppressed and GRE sequences, corresponding to fluid signal seen.&#x0D; Results: Of 88 patients, the mean age was 54.022±5.19 years. Ultrasound diagnosed rotator cuff tears in 42(47.7%) patients, and MRI diagnosed rotator cuff tears in 44(50.0%) patients. Diagnostic accuracy of ultrasound taking MR imaging as the gold standard showed sensitivity as 81.82%, specificity as 77.27%, negative predicted value as 78.26%, positive predicted value as 80.95%, and overall diagnostic accuracy as 79.55%. A moderate agreement was found between ultrasound and MRI findings (p-value=0.591).&#x0D; Conclusion: The findings of the current study showed significant moderate agreement between ultrasound and MR imaging in the determination of rotator-cuff tears.

Branch duct-intraductal papillary mucinous neoplasms (BD-IPMNs): an MRI-based radiomic model to determine the malignant degeneration potential.

Branch duct-intraductal papillary mucinous neoplasms (BD-IPMNs) are the most common pancreatic cystic tumors and have a low risk of malignant transformation. Features able to early identify high-risk BD-IPMNs are lacking, and guidelines currently rely on the occurrence of worrisome features (WF) and high-risk stigmata (HRS). In our study, we aimed to use a magnetic resonance imaging (MRI) radiomic model to identify features linked to a higher risk of malignant degeneration, and whether these appear before the occurrence of WF and HRS. We retrospectively evaluated adult patients with a known BD-IPMN who had had at least two contrast-enhanced MRI studies at our center and a 24-month minimum follow-up time. MRI acquisition protocol for the two examinations included pre- and post-contrast phases and diffusion-weighted imaging (DWI)/apparent diffusion coefficient (ADC) map. Patients were divided into two groups according to the development of WF or HRS at the end of the follow-up (Group 0 = no WF or HRS; Group 1 = WF or HRS). We segmented the MRI images and quantitative features were extracted and compared between the two groups. Features that showed significant differences (SF) were then included in a LASSO regression method to build a radiomic-based predictive model. We included 50 patients: 31 in Group 0 and 19 in Group 1. No patients in this cohort developed HRS. At baseline, 47, 67, 38, and 68 SF were identified for pre-contrast T1-weighted (T1-W) sequence, post-contrast T1-W sequence, T2-weighted (T2- W) sequence, and ADC map, respectively. At the end of follow-up, we found 69, 78, 53, and 91 SF, respectively. The radiomic-based predictive model identified 16 SF: more particularly, 5 SF for pre-contrast T1-W sequence, 6 for post-contrast T1-W sequence, 3 for T2-W sequence, and 2 for ADC. We identified radiomic features that correlate significantly with WF in patients with BD-IPMNs undergoing contrast-enhanced MRI. Our MRI-based radiomic model can predict the occurrence of WF.

MRI assessment of rectal cancer response to neoadjuvant therapy: a multireader study.

A watch and wait strategy with the goal of organ preservation is an emerging treatment paradigm for rectal cancer following neoadjuvant treatment. However, the selection of appropriate patients remains a challenge. Most previous efforts to measure the accuracy of MRI in assessing rectal cancer response used a small number of radiologists and did not report variability among them. Twelve radiologists from 8 institutions assessed baseline and restaging MRI scans of 39 patients. The participating radiologists were asked to assess MRI features and to categorize the overall response as complete or incomplete. The reference standard was pathological complete response or a sustained clinical response for > 2years. We measured the accuracy and described the interobserver variability of interpretation of rectal cancer response between radiologists at different medical centers. Overall accuracy was 64%, with a sensitivity of 65% for detecting complete response and specificity of 63% for detecting residual tumor. Interpretation of the overall response was more accurate than the interpretation of any individual feature. Variability of interpretation was dependent on the patient and imaging feature investigated. In general, variability and accuracy were inversely correlated. MRI-based evaluation of response at restaging is insufficiently accurate and has substantial variability of interpretation. Although some patients' response to neoadjuvant treatment on MRI may be easily recognizable, as seen by high accuracy and low variability, that is not the case for most patients. • The overall accuracy of MRI-based response assessment is low and radiologists differed in their interpretation of key imaging features. • Some patients' scans were interpreted with high accuracy and low variability, suggesting that these patients' pattern of response is easier to interpret. • The most accurate assessments were those of the overall response, which took into consideration both T2W and DWI sequences and the assessment of both the primary tumor and the lymph nodes.

Optimized visualization of focal liver lesions and vascular structures in real-time T1-weighted gradient echo sequences for magnetic resonance-guided liver procedures.

This study aimed to determine the optimal sequence parameters of a real-time T1-weighted (T1w) gradient echo (GRE) sequence for magnetic resonance (MR)-guided liver interventions. We included 94 patients who underwent diagnostic liver MR imaging (MRI) and acquired additional real-time T1w GRE sequences with a closed 1.5-T MRI scanner 20 min after a liver-specific contrast agent was injected. In four measurement series, one of the following four sequence parameters was changed, and repeated scans with different values for this parameter were acquired: flip angle (FA) (10-90°), repetition time (TR) (5.47-8.58 ms), bandwidth (BW) (300-700 Hz/pixel), and matrix (96 × 96-256 × 256). Two readers rated the visualizations of the target and risk structures (7-point Likert scale) and the extent of artifacts (6-point Likert scale); they also quantified the lesion-liver contrast ratio, the lesion-liver contrast-to-noise ratio (CNR), and the liver signal-to-noise ratio (SNR). Substratification analyses were performed for differences in overall visual and quantitative assessments depending on the lesion size, type, and the presence of cirrhosis. For the utilized FAs and matrix sizes, significant differences were found in the visual assessments of the conspicuity of target lesions, risk structures, and the extent of artifacts as well as in the quantitative assessments of lesion-liver contrast ratios and liver SNRs (all P < 0.001). No differences were observed for modified TR and BW. Significantly increased conspicuity of the target and vascular structures was observed for both higher FAs and matrix sizes, while the ghosting artifacts increased and decreased, respectively. For primary liver tumors compared with metastatic lesions, and for cirrhotic livers compared with normal liver parenchyma, significantly decreased conspicuity of the target lesions (P = 0.005, P = 0.005), lesion-liver CNRs (P = 0.005, P = 0.032), and lesion-liver contrast ratios (P = 0.015, P = 0.032) were found. All results showed no significant correlation with lesion size. We recommend an FA of 30°-45° and a matrix size of 128 × 128-192 × 192 for MR-guided liver interventions with real-time T1w sequences to provide a balance between good visualizations of target and risk structures, high signal intensities, and low ghosting artifacts. The visualization of the target lesion may vary due to clinical conditions, such as lesion type or associated chronic liver disease.

Diagnostic value of 3D T1-weighted gradient-echo and 2D T1-weighted in-phase and out-of-phase gradient-echo sequences for appendicitis diagnosis in pregnant women.

This study compared the diagnostic value of 3D T1-weighted (T1W) gradient-echo (GRE) and 2D T1W in-phase and out-of-phase GRE sequences for appendicitis diagnosis in pregnant women. This retrospective study included 25 pregnant patients with suspected appendicitis who underwent 1.5 Tesla abdominal magnetic resonance imaging and had definitive diagnoses. Four doctors approached four separate imaging groups: A (only T2-weighted image [T2WI] sequences), B (T2WI and 3D T1W GRE sequences), C (T2WI and T1W in-phase and out-of-phase GRE sequences), and D (T2WI, 3D T1W GRE, and T1W in-phase and out-of-phase GRE sequences). The kappa (κ) index was used to compare the appendicitis diagnostic results between groups. The diagnostic value of these sequences in the diagnosis of pregnancy appendicitis was also evaluated. Groups A and C had average consistency with definitive diagnosis (κ = 0.6), lower than Groups B and D (κ = 0.865), indicating a high definite diagnosis consistency. Groups B and D had similarly high sensitivity (80%), specificity (100%), positive predictive value (100%), negative predictive value (95.2%), and accuracy (ACC) (96%), higher than Groups A and C (60%, 95%, 75%, 90.5%, and 88%, respectively). 3D T1W-GRE sequences improve appendicitis diagnosis in pregnancy compared to T2W sequences alone. Adding in and out phase GRE sequences do not increase diagnostic ACC.

Razlike u dijagnostičkoj snazi STIR i T1W sekvence kod Mr nalaza koštane modrice akutno traumatizovanog kolena

Objective. Increasing use of magnetic resonance imaging (MRI) in acute knee trauma has led to increased awareness of bone bruises (BB). Post-traumatic BB is the only predictor of early osteoarthritis. The aim of our research is to determine the way in which it is possible to observe and precisely determine the localization, size, and number of BBs, by the correct selection of Mr imaging sequences. Methods. Mr examinations of the knees performed during 2012-2013 in 100 subjects with an acute knee injury sustained during sports were retrospectively analyzed from the personal archive. All examinations were done in the first month after the trauma. Examinations were performed on an open-type MRI with a power of 0.3T. A standard protocol was used with sequences of spin echo T1-weighted in the sagittal plane, fat suppression T2-weighted in the sagittal, coronal, and axial planes, and Short Tau Inversion Recovery (STIR) in the coronal plane. The presence and arrangement of BB were analyzed. The difference in the frequency of BB findings in STIR compared to the T1W sequence and the assessment of the visibility of BB in both sequences were analyzed. Results. BB findings were observed in 51% of subjects. BB is, after effusion, the second, most frequent pathological finding on Mr examination in acute knee trauma. A significant statistical difference was determined by the Wilcoxon test (Z=-5.067, p=0.000) between the T1W and STIR sequence, which indicates that the STIR sequence is convincingly more sensitive than the T1W sequence for the diagnosis of BB. Conclusion. It was concluded that STIR sequence provides better visibility of BB compared to T1W sequence.

Gadolinium deposition in the brain of patients with relapsing-remitting multiple sclerosis after 10 years of follow-up

Background/Aim. Since 2014 and the publication of the results of the first study on the accumulation of gadolinium contrast, we have witnessed a growing body of evidence on the deposition and retention of gadolinium in the brain after the use of gadolinium-based contrast agents (GBCAs). However, there is still no strong clinical evidence of the adverse effects of GBCAs on the brain parenchyma. The aim of the study was to determine the existence of gadolinium deposits in the brain of patients with relapsing-remitting multiple sclerosis after a ten-year follow-up period. During this period, the patients have regularly, each year, undergone magnetic resonance imaging (MRI) with the administration of gadolinium contrast (gadopentetate dimeglumine ? Magnevist?) in order to follow the course of the disease. Methods. A cohort of 20 patients was formed for the purpose of this study. The ratio of the values of the signal intensity (SI) of different regions of the brain-to-cerebrospinal fluid (CSF) was com-pared for each patient on the initial MRI examination and the MRI examination ten years later. Results. Frontal cortex-to-CSF (p &lt; 0.01), occipital cortex-to-CSF (p &lt; 0.01), the white matter of the corona radiata-to-CSF (p &lt; 0.01), parietal cortex-to-CSF (p &lt; 0.05), thalamus-to-CSF (p = 0.051), putamen-to-CSF (p = 0.06), and anterior and posterior limb of the capsula interna-to-CSF (p = 0.062) SI ratios increased after multiple gadopentetate administrations. An increase in the absolute values of the T1- weighted (T1W) signal in three-quarters of patients was registered in the frontal and occipital cortex and cerebellar hemispheres. A slightly smaller increase in SI, but still greater than 55?65%, was registered in structures of the parietal cortex, putamen, cornu anterior and posterior of the capsula interna, corpus callosum (CC) splenium, pons, thalamus, nucleus caudatus, substantia nigra, CC genu, and temporal cortex. Conclusion. In the cohort of 20 patients, there was a statistically significant increase in SI in the pre-contrast T1W sequence in the following structures: frontal, parietal, and occipital cortex, as well as supratentorial white matter. This result speaks in favor of the existence of chronic accumulation of gadolinium contrast agent gadopentetate dimeglumine in brain structures.

752 CARDIOGENIC SHOCK AS THE FIRST PRESENTATION OF ACUTE ANTRACYCLINE CARDIOTOXICITY: A CLINICAL CASE

Abstract Background Several therapeutic strategies are available for cancer patients, leading to a longer life expectancy; however, each drug might have different side effects, which increase morbidity and mortality. Cardiovascular diseases are one of the most frequent and dramatic of these side effects, leading to interruption of a potentially lifesaving treatment or hesitating into heart failure. Clinical Case A 50 year-old female with recent diagnosis of breast cancer presented to our Emergency Department (ED) for asthenia, vomiting and dyspnea. A first dose of epirubicin and cyclophosphamide as neoadjuvant chemotherapy (CT) was administered three days before the onset of symptoms. Screening echocardiogram performed before starting the CT showed normal systolic ejection fraction, normal diastolic function and no valvular disease. At ED admission, the patient presented hypotension, tachycardia, sweating and mental confusion. The ECG showed sinus tachycardia with diffuse ST segment elevation and diffuse low QRS voltages. Echocardiogram proved severe left dysfunction (LVEF 15%) with low cardiac output (LVOT VTI 6 mm) and elevated ventricular filling pressure (E/e’ 26). EAB showed severe hyperlactacidemia. The diagnosis of cardiogenic shock was done and high doses of dobutamine and noradrenaline were started. Laboratory values confirmed multiorgan involvement, in absence of any signs of inflammation and infection. The coronary angiography performed revealed normal coronary arteries and elevated left ventricular end-diastolic pressure (LVEDP 29 mmHg). Despite pharmacological therapy, the patient's condition worsened so we proceeded to IMPELLA CP implantation and started methylprednisolone 10 mg/kg for three days with subsequent tapering doses. After 24 hours, we obtained hemodynamic stability and hyperlactacidemia clearance. Unfortunately, myelotoxicity and marked piastrinopenia (until 16 000*10 9/L) complicated the clinical course; for this reason, we stopped unfractionated Heparin (UHF) and no anticoagulant therapy, other the one in purge solution, was performed. CMR revealed diffuse signal enhancement during the T2w sequences associated with a global enhancement of T2 Mapping values due to general edema, a global intramyocardial strengthening, a significant enhancement of the T1 mapping values and extracellular volume were described at the delayed enhancement sequences. The hemodynamic conditions progressively improved during the hospitalization and the IMPELLA pump was removed. Serial echocardiograms documented an improvement of the ejection fraction and further mild reduction of ventricular filling pressure (E/e’ 8) normal right ejection fraction and initial inferior vena cava collapsibility. All the inotropic supports were suspended; we introduced beta-blocker, ACE-inhibitors, subsequently replaced with sacubitril/valsartan, well tolerated. Conclusion Acute cardiotoxicity with possible life-threatening conditions regardless of the basal cardiovascular risk class is a rare clinical condition, but needs further investigation. Future researches are warranted to determine the molecular mechanisms underlying cardiotoxicity to contain the side effects, maximize the benefit of the oncological therapy and, when necessary, select the best therapeutic option.

An atypical imaging characteristic of calvarial metastasis of neuroblastoma as multiple multi-loculated cystic masses with internal blood-fluid levels: a case report

As the third most common malignancy of childhood, Neuroblastoma has a great propensity to metastasize to multiple organs. The most common site of metastasis is the bone and bone marrow. Concerning the central nervous system, neuroblastoma usually involves the calvarium and the external dural surface. The skull metastases may show different appearances, including: multiple lytic bone lesions, bone thickening, hair-on-end periosteal reaction, irregular suture widening and/or plaque like epidural deposits. Here we present a case of metastatic neuroblastoma, appearing as multiple multi-loculated cystic epidural masses with internal blood-fluid levels as a rare imaging manifestation of calvarial metastasis. An 8-year-old boy with known history of autism, presented to the emergency department with a 3-month history of intermittent fever, malaise and myalgia and headache along with significant weight loss. Laboratory examination revealed elevated ESR and CRP and anemia. On Abdomino-Pelvic imaging a well-defined, 45*30*24mm, solid-cystic mass was observed, replacing the normal left adrenal gland. On brain MRI, multiple multi-loculated cystic, lentiform masses were observed on the external surface of cerebral hemispheric dura. Multiple fluid-fluid levels were noted in the locules in some of which the dependent fluid was hyperintense on T1w and FLAIR and hypointense on T2w sequences, compatible with blood, representing blood-fluid level. The wall and septa of the masses, enhanced after contrast administration. Associated abnormal marrow signal and aggressive type periosteal reactions were identified in the overlying bone. All of the lesions had increased uptake in MIBG scan. Bone marrow biopsy revealed small round cells, diagnostic for neuroblastoma. The patient underwent chemotherapy treatment. All calvarial/epidural metastatic lesions resolved after chemotherapy and residual adrenal tumor was resected. Cystic epidural lesions, especially when associated with adjacent abnormal bone marrow signal, or periosteal reaction and containing blood-fluid level should raise the suspicion of a calvarial metastasis.

NIMG-16. COMPARISON OF A STIR- AND T1-WEIGHTED-BASED RADIOMICS MODEL TO DIFFERENTIATE BETWEEN PLEXIFORM NEUROFIBROMAS AND MALIGNANT PERIPHERAL NERVE SHEATH TUMORS IN NEUROFIBROMATOSIS TYPE 1 (NF1)

Abstract BACKGROUND Plexiform neurofibromas (PNF) and malignant peripheral nerve sheath tumors (MPNST) are best visualized on short TI inversion recovery (STIR) sequences on MRI. However, STIR sequences are not routinely acquired in the clinical setting. T1-weighted pre-contrast (T1W) sequences are more standardly obtained but provide insufficient contrast for tumor identification. We developed a radiomics model based on STIR and T1W sequences to differentiate between NF1-associated PNF and MPNST. METHODS Using a 3D quantitative imaging analysis software (3DQI), 68 MPNST and 79 PNF from 134 participants at nine centers were segmented on STIR sequences (if available) or T2 fat-saturated or T1-weighted fat-saturated post-contrast sequences. Tumor regions of interest were co-registered to T1W sequences. Standard pre-processing included N4 bias field correction, intensity normalization (mean 120 SI, SD 80 SI), and resampling (1 mm3 voxel resolution). 107 radiomic features were extracted using PyRadiomics. To classify tumors as PNF or MPNST, we applied the Boruta algorithm and correlation removal for selection of important features. A Random Forest model was built using the top five selected features. The data were divided into a training/validation and test set (7:3 ratio). Five-fold cross-validation was performed and repeated 100 times. Model performance was evaluated using AUC, sensitivity, specificity, accuracy, and 95% CI. RESULTS For the STIR-based model, AUC was 0.856 (95% CI 0.727-0.984), sensitivity 0.6, specificity 0.833, and accuracy 0.727 in the test set. For the T1W-based model, AUC was 0.867 (95% CI 0.743-0.990), sensitivity 0.8, specificity 0.79, and accuracy 0.794 in the test set. CONCLUSIONS Our radiomics models demonstrate high and comparable performance to distinguish between PNF and MPNST on STIR and T1W sequences. Our inclusion of multicenter MRIs enhances model generalizability. These models can potentially be integrated into the radiologic workflow to help clinicians in the early identification of MPNST or pre-malignant atypical neurofibromas on clinical MRIs.

RADT-25. UNDERSTANDING PATTERNS OF TUMOUR INFILTRATION IN PATIENTS WITH MULTIFOCAL GLIOBLASTOMA AND IMPACT ON SURVIVAL OUTCOMES

Abstract BACKGROUND Multifocal glioblastoma(MF-G) are often clustered with presumed uniform worse prognosis. This study explores varying patterns of infiltration of MF-G in relation to radiological features, including presence of contiguous MRI T2-weighted abnormalities and adjacent neural tract pathway involvement. METHODS Consecutive patients with glioblastoma from 2016-2020 managed under EORTC-NCI(Stupp60Gy) Protocol had manual tumour segmentation on T1gd and T2w sequences. Multifocal disease was defined as T1gd or solid T2w-abnormality a minimum of 10mm from the dominant lesion. Number of foci, maximum dimension, cortical/white matter site and distance from dominant lesion were recorded. Presence of contiguous T2w-abnormality was recorded, and correlated to ten major neural tract pathways. Progression-free(PFS) and overall survival(OS) were analysed. RESULTS Forty of 177 patients(23%) were identified with MF-G. These had less near-total resection(p = 0.001), but no difference in ECOG(p = 0.16), or MGMT-methylation(p=0.23). Foci had median size of 14.5mm (q1-3: 10-20); 73% enhancing and 58% solitary. Median distance from dominant lesion was 23mm (q1-3:15-25). Contiguous T2w abnormality and involvement of identified neural tract was evident in 78% and 83% respectively. The multifocal lesion was based in cortex in 33%, and white matter in 67%. Survival outcomes were worse with MF-G: OS (p &amp;lt; 0.01) was 16.0 months (95%CI: 13.6-18.4) versus 19.9 months (95%CI: 17.6-22.2); and PFS (p = 0.01) was 10.8 months (95%CI: 9.9-11.7) versus 13.6 months (95%CI: 11.1-16.1). Improved PFS was associated with larger lesion size(p = 0.04), and cortical lesions(0.04). Those MF-G with contiguous T2w-abnormality(p = 0.06); identified neural tract(p = 0.07) or enhancement(p = 0.08) had trend to worse PFS. MGMT(p = 0.10), ECOG(p = 0.62) and extent of resection(p = 0.07) were not associated with PFS, nor radiological factors of foci number(p = 0.19) and lesion distance(p = 0.16). CONCLUSIONS Radiological pattern of infiltration in MF-G is associated with different natural history. Improved PFS was associated with cortical foci without contiguous T2 abnormality or tract involvement. Recognising infiltration patterns may impact on RT target volume delineation and understanding prognosis.

PHSPP05 Presentation Time: 3:10 PM: Optimization Strategies in MR-Only Workflow for Interstitial and Intracavitary Gynecological HDR Brachytherapy

<h3>Purpose</h3> Image-guided interstitial and intracavitary gynecological brachytherapy (IGBT) is advancing towards MR-only workflows because of MR's superior soft-tissue contrast for tumor delineation and tissue segmentation. However, current treatment planning still necessitates the use of CT/MR fusion to aid in needle reconstruction and quality assurance (QA). In this work, we present strategies to visualize needles on MR and provide QA procedures for MR-only IGBT with comparisons to the conventional CT/MR approach. <h3>Materials and Methods</h3> Three 6F interstitial plastic needles and one CT/MR-compatible intrauterine tandem and ring (T&R) applicator set were examined in this study with the Flexitron afterloading system (Elekta Brachytherapy, Netherlands). To visualize the needles, they were immersed in demineralized water and scanned without markers in a 3T MRI system (Signa Premier; GE Healthcare, Milwaukee, WI). MR images were acquired with three protocols: 3D T1W (TR\TE 552\10 ms, and 1 mm voxel), 3D T2W (TR\TE 3051\104 ms, and 1 mm voxel) and silent Zero TE sequence (TR\TE 1060\20 ms, and 0.58 mm voxel). For QA, a 2D MR protocol (T1W, 7-10 mm thick slice) was utilized that allowed a projection-like image of an EBT3-film-based setup which was also imaged (with CT/x-ray markers) in CT (Philips, Netherlands) and x-ray imager (Varian Medical Systems, Palo Alto, CA). This setup consists of attaching catheters and four vitamin-D pills to EBT3 film pieces. The four corners of each film piece (5" x 4") were marked with skin markers that are visible in CT and MR images. These skin markers served as surrogates for a 4-point registration system between all images, and the vitamin-D pills were used to assess registration quality. An efficient film handling/scanning protocol was designed for this work and the source first dwell position (FDP) on the film was determined using a commissioned source localization algorithm. The FDP was compared between film, x-ray/CT markers, and applicator library models. <h3>Results</h3> For needle visualization, ZTE images generated a positive contrast for the interstitial needles as compared to conventional T1 and T2 images (See Figure). For QA, the 2D MR slice and x-ray image clearly displayed applicators, needles, vitamin-D pills, and skin markers allowing accurate registration to film images, visualization, and localization of the catheters, source positions, and markers in one fused image (See Figure). The tandem tip from MR was 1.1 mm longer than that of the x-ray and model which was not evident in the vitamin-D matching, implying a potential MR artifact at the tip (Sub-Figure B) which should be taken into account while planning. FDP reconstruction errors from the needle tip in MR with respect to film and x-ray markers were less than 1 mm (Sub-Figure D). <h3>Conclusions</h3> While further investigation is required, ZTE imaging offers a promising alternative to CT imaging for needle reconstruction supporting MR-only gynecological brachytherapy treatment planning. However, MR-only workflow requires special considerations in QA to account for possible systematic shifts that could exceed the level of accuracy achieved in x-ray-based IGBT.

The effect of respiration-induced target motion on 3D magnetic resonance images used to guide radiotherapy

3D Magnetic Resonance Imaging (MRI) is used in radiation therapy for reference planning and, lately, for adaptive treatments on MR accelerators. This study aimed to investigate the impact of different types of respiratory motion on the apparent target position and extent in such scans. An MRI motion phantom with a 30mm diameter target was used to simulate cranial-caudal (CC) motion and imaged at an MR-Linac using a standard clinically released 3D T2w sequence. Scans were acquired for each combination of functions (sin(t), sin4(t) and sin12(t)), peak-to-peak amplitudes(5, 10, 15 and 20mm), and periods (4, 5 and 6s). Furthermore, respiration CC motion patterns fromtwo patients were used. Motion functions were shifted such that the time average target position would match a static reference scan at 0-position. The target was automatically identified in coronal and sagittal images using k-means clustering. The mean position and area of the target were calculated and compared to the reference scan. Artefacts increased with amplitude and depended on the motion type. Sin(t) and sin4(t) oscillations resulted in a blurring of the target, which led to an increased target area, while sin12(t) motion did not show significant changes in the target area. However, for the sin12(t) motion, the offset in apparent position was prominent, while that was not the case for the sin(t) and sin4(t) motion. The patient respiration motion profiles showed similar trends. In 3D MRI, target motion can change apparent tumour extent and apparent position. The changes increase with motion amplitude and depend on the motion type.