Conventional MRI Research Articles

Investigating acoustic startle habituation and prepulse inhibition with silent functional MRI and electromyography in young, healthy adults.

Startle habituation and prepulse inhibition (PPI) are distinct measures of different sensory information processes, yet both result in the attenuation of the startle reflex. Identifying startle habituation and PPI neural mechanisms in humans has mostly evolved from acoustic-focused rodent models. Human functional magnetic resonance imaging (fMRI) studies have used tactile startle paradigms to avoid the confounding effects of gradient-related acoustic noise on auditory paradigms and blood-oxygen-level-dependent (BOLD) measures. This study aimed to examine the neurofunctional basis of acoustic startle habituation and PPI in humans with silent fMRI. Using silent fMRI and simultaneous electromyography (EMG) to measure startle, the neural correlates of acoustic short-term startle habituation and PPI [stimulus onset asynchronies (SOA) of 60 ms and 120 ms] were investigated in 42 healthy adults (28 females). To derive stronger inferences about brain-behaviour correlations at the group-level, models included EMG-assessed measures of startle habituation (regression slope) or PPI (percentage) as a covariate. A linear temporal modulator was modelled at the individual-level to characterise functional changes in neural activity during startle habituation. Over time, participants showed a decrease in startle response (habituation), accompanied by decreasing thalamic, striatal, insula, and brainstem activity. Startle habituation was associated with the linear temporal modulation of BOLD response amplitude in several regions, with thalamus, insula, and parietal lobe activity decreasing over time, and frontal lobe, dorsal striatum, and posterior cingulate activity increasing over time. The paradigm yielded a small amount of PPI (9-13%). No significant neural activity for PPI was detected. Startle habituation was associated with the thalamus, putamen, insula, and brainstem, and with linear BOLD response modulation in thalamic, striatal, insula, parietal, frontal, and posterior cingulate regions. These findings provide insight into the mediation and functional basis of the acoustic primary startle circuit. Instead, whilst reduced compared to conventional MRI, scanner noise may have disrupted prepulse detection and processing, resulting in low PPI and impacting our ability to map its neural signatures. Our findings encourage optimisation of the MRI environment for acoustic PPI-based investigations in humans. Combining EMG and functional neuroimaging methods shows promise for mapping short-term startle habituation in healthy and clinical populations.

Comparison between the diagnostic utility of three-dimensional fluid attenuated inversion recovery (3D FLAIR) and three dimensional double inversion recovery (3D DIR) magnetic resonance sequences in the assessment of overall load of multiple sclerosis lesions in the brain

BackgroundMultiple sclerosis (MS) is a complex CNS demyelinating disease. Assessment of MS plaques in specific anatomic locations in the brain was challenging to detect by conventional MRI sequences. So, this study aimed to compare the diagnostic accuracy of 3D FLAIR (Fluid attenuation inversion recovery), or 3D DIR (Double inversion recovery) sequences to conventional 2D FLAIR and T2 sequences in detecting MS plaques in different anatomic sites, as well as counting the total lesion burden.MethodsA comparative cross-sectional study enrolled 30 MS patients on the basis of McDonald’s criteria 2017. All participants underwent a brain MRI study including 3D FLAIR or 3D DIR sequences, conventional 2D FLAIR, and T2 sequences.ResultsNo statistically significant difference between the 3D DIR and 3D FLAIR in total lesion (plaque) burden results; however, when each is compared to the conventional ones, both are superior. 3D FLAIR detected the most significant number of plaques in the periventricular region, followed by 2D FLAIR and T2W sequences, with 3D DIR being the least accurate in this region. Meanwhile, 3D DIR was the most precise and can detect a statistically significant number of cortical plaques compared to the 3D FLAIR and the conventional sequences. No statistically significant results on which sequence is best in regard to infratentorial plaque detection.Conclusion3D FLAIR and 3D DIR were superior to 2D FLAIR and T2 sequences in detecting overall lesion burden in MS. Moreover, the 3D DIR sequence was the most precise in the detection of the cortical plaques.

Usefulness of combined pseudo-continuous arterial spin labelling and spectroscopic analysis in schizophrenic Egyptian population sample

BackgroundSchizophrenia is a prevalent psychiatric disorder that affects 1% of the global population. Schizophrenia frequently begins in late adolescence or early adulthood, causing significant educational, social, and economic costs for people and society. Functional neuroimaging research on schizophrenia physiopathology has been beneficial. Arterial spin labelling (ASL) is one of functional magnetic resonance imaging (fMRI) technologies that assess brain function without radiation. ASL uses magnetic resonance (MR) imaging to quantify tissue-level brain perfusion non-invasively. Arterial spin labelling (ASL) is one of the functional magnetic resonance imaging (fMRI) technologies that assess the brain function without radiation hazards. ASL uses magnetic resonance (MR) imaging to quantify tissue-level brain perfusion non-invasively. Many publications were performed on role of different advanced MRI techniques in schizophrenia, but our study insisted on the added value of combined ASL and MRS over the conventional MRI in schizophrenic Egyptian population sample.Aim of the workThe purpose of this work was to evaluate the added value of combined ASL-perfusion MRI and MRS in schizophrenic patients.MethodsThis prospective case–control study was carried out on two groups: First group was 30 patients who were diagnosed clinically as schizophrenic patients, and second group was 20 healthy volunteers as a control group for comparison in the period from August 2021 till July 2022.ResultsThe majority of newly diagnosed cases had significant higher positive symptoms than chronic cases. According to arterial spin labelling (ASL) data, rCBF was noticed to be reduced in anterior cingulate, frontal lobe, and parietal lobe of both patients’ subgroups but more significant in chronically ill patients. Convergent results of decreased rCBF were also found in the parietal lobe and occipital lobe. Magnetic resonance spectroscopic analysis showed that NAA was decreased in the anterior cingulate cortex, thalami and basal ganglia of the newly diagnosed cases more than chronic cases. The ASL-MRI perfusion accurately detected the hypo-perfusion of different brain regions with sensitivity 100%, specificity 66.67%, positive predictive value 96.43%, negative predictive value 100%, and accuracy 96.67%, while MR spectroscopy showed sensitivity 100%, specificity 33.33%, positive predictive value 93.10%, negative predictive value 100%, and accuracy 93.33% in evaluation of changes of brain metabolites.ConclusionASL is a promising functional MRI technique that can produce together with MRS quantitative information about the metabolites of different brain regions. The ASL-MRI appears as a reliable non-invasive technique to measure cerebral blood flow and identify decreased rCBF without any contrast administration, and it could be repeatable which helps in early diagnosis as well as follow-up of the progression of the disease.

Gadolinium Enhanced T2 FLAIR is an Imaging Biomarker of Radiation Necrosis and Tumor Progression in Patients with Brain Metastases.

Differentiating radiation necrosis (RN) from tumor progression (TP) after radiotherapy for brain metastases is an important clinical problem requiring advanced imaging techniques which may not be widely available and are challenging to perform at multiple time points. The ability to leverage conventional MRI for this problem, could have meaningful clinical impact. The purpose of this study was to explore contrast enhanced T2 FLAIR (T2FLAIRc) as a new imaging biomarker of RN and TP. This single-institution retrospective study included patients with treated brain metastases undergoing DSC-MRI between January 2021 and June 2023. Reference standard assessment was based on histopathology or serial follow-up including results of DSC-MRI for a minimum of 6 months from the first DSC-MRI. The index test was implemented as part of the institutional brain tumor MRI protocol and preceded the first DSC-MRI. T2FLAIRc and gadolinium enhanced T1 MPRAGE (T1c) signal were normalized against normal brain parenchyma and expressed as z-score. Mean signal intensity of enhancing disease for RN and TP groups were compared using unpaired t-test. Receiver operator characteristic (ROC) curves and area under the ROC curve (AUC) were derived by bootstrapping. DeLong test was used to compare AUC. 56 participants (mean age, 62 years +/-12.7 [SD]; 39 females); 28 RN, 28 TP were evaluated. The index MRI was performed on average 73 days +/-34 [SD] before the first DSC-MRI. Significantly higher z-scores were found for RN using T2FLAIRc (8.3 versus 5.8, p<0.001) and T1c (4.1 versus 3.5, p=0.02). AUC for T2FLAIRc (0.83, 95% CI, 0.72-0.92) was greater than T1c (0.70, 95% CI, 0.560.83) (p = 0.04). The AUC of DSC derived rCBV (0.82, 95% CI, 0.70-0.93) was not significantly different from T2FLAIRc (p = 0.9). A higher normalized T1c and T2FLAIRc signal intensity was found for RN. In a univariable test, mean T2FLAIRc signal intensity of enhancing voxels showed good discrimination performance for distinguishing RN from TP. The results of this work demonstrate the potential of T2FLAIRc as an imaging biomarker in the work-up of RN in patients with brain metastases. AUC = area under the receiver operating characteristic curve; RN = radiation necrosis; ROC = receiver operating characteristic; SRS = stereotactic radiosurgery; T1c = contrast enhanced T1; T2FLAIRc = contrast enhanced T2 FLAIR; TP = tumor progression.

PSMA PET/MR is a New Imaging Option for Identifying Glioma Recurrence and Predicting Prognosis.

Glioma is characterized by a high recurrence rate, while the results of the traditional imaging methods (including magnetic resonance imaging, MRI) to distinguish recurrence from treatment-related changes (TRCs) are poor. Prostate-specific membrane antigen (PSMA) (US10815200B2, Deutsches Krebsforschungszentrum, German Cancer Research Center) is a type II transmembrane glycoprotein overexpressed in glioma vascular endothelium, and it is a promising target for imaging and therapy. The study aimed to assess the performance of PSMA positron emission tomography/ magnetic resonance (PET/MR) for diagnosing recurrence and predicting prognosis in glioma patients. Patients suspected of glioma recurrence who underwent 18F-PSMA-1007 PET/MR were prospectively enrolled. Eight metabolic parameters and fifteen texture features of the lesion were extracted from PSMA PET/MR. The ability of PSMA PET/MR to diagnose glioma recurrence was investigated and compared with conventional MRI. The diagnostic agreement was assessed using Cohen κ scores and the predictive parameters of PSMA PET/MR were obtained. Kaplan-Meier method and Cox proportional hazard model were used to analyze recurrence- free survival (RFS) and overall survival (OS). Finally, the expression of PSMA was analyzed by immunohistochemistry (IHC). Nineteen patients with a mean age of 48.11±15.72 were assessed. The maximum tumorto- parotid ratio (TPRmax) and texture features extracted from PET and T1-weighted contrast enhancement (T1-CE) MR showed differences between recurrence and TRCs (all p <0.05). PSMA PET/MR and conventional MRI exhibited comparable power in diagnosing recurrence with specificity and PPV of 100%. The interobserver concordance was fair between the two modalities (κ = 0.542, p = 0.072). The optimal cutoffs of metabolic parameters, including standardized uptake value (SUV, SUVmax, SUVmean, and SUVpeak) and TPRmax for predicting recurrence were 3.35, 1.73, 1.99, and 0.17 respectively, with the area under the curve (AUC) ranging from 0.767 to 0.817 (all p <0.05). In grade 4 glioblastoma (GBM) patients, SUVmax, SUVmean, SUVpeak, TBRmax, TBRmean, and TPRmax showed improved performance of AUC (0.833-0.867, p <0.05). Patients with SUVmax, SUVmean, or SUVpeak more than the cutoff value had significantly shorter RFS (all p <0.05). In addition, patients with SUVmean, SUVpeak, or TPRmax more than the cutoff value had significantly shorter OS (all p <0.05). PSMA expression of glioma vascular endothelium was observed in ten (10/11, 90.9%) patients with moderate-to-high levels in all GBM cases (n = 6/6, 100%). This primitive study shows multiparameter PSMA PET/MR to be useful in identifying glioma (especially GBM) recurrence by providing excellent tumor background comparison, tumor heterogeneity, recurrence prediction and prognosis information, although it did not improve the diagnostic performance compared to conventional MRI. Further and larger studies are required to define its potential clinical application in this setting.

Brain Diffusion Changes in Perinatal Asphyxia Cases.

Prolonged perinatal asphyxia (PA) may cause hypoxic-ischemic damage to the brain. The aim of this study was to investigate the brain diffusion changes of patients with PA and examine the relationship with brain damage. This retrospective study included 55 patients diagnosed with PA, separated into mild and severe PA groups. For the evaluation of brain damage in all the study neonates, brain and diffusion MRI scans were performed using a 3T device. The scans were taken between 5 and 10 days postnatal, after completion of hypothermia treatment, in accordance with the standard clinical protocol of our institution. Apparent diffusion coefficient (ADC) values of the lentiform nucleus, thalamus, frontal white matter, and posterior limbs of the internal capsule were measured. Minitab package programs and SPSS version 20.0 software were used for statistical analysis and graphic drawing. Spearman's rank correlation analysis was used. The bilateral lentiform nucleus, thalamus, frontal white matter, and posterior limbs of the internal capsule ADC values were significantly higher in the severe PA group than in the mild PA group. In neonates with severe perinatal asphyxia, brain damage can be evaluated on diffusion-weighted imaging (DWI) of the cerebral deep white matter and basal ganglia. DWI, imaging with conventional brain MRI comes to the fore in clinical importance in PA patients.

Fully automated hybrid approach on conventional MRI for triaging clinically significant liver fibrosis: A multi-center cohort study.

Establishing reliable noninvasive tools to precisely diagnose clinically significant liver fibrosis (SF, ≥F2) remains an unmet need. We aimed to build a combined radiomics-clinic (CoRC) model for triaging SF and explore the additive value of the CoRC model to transient elastography-based liver stiffness measurement (FibroScan, TE-LSM). This retrospective study recruited 595 patients with biopsy-proven liver fibrosis at two centers between January 2015 and December 2021. At Center 1, the patients before December 2018 were randomly split into training (276) and internal test (118) sets, the remaining were time-independent as a temporal test set (96). Another data set (105) from Center 2 was collected for external testing. Radiomics scores were built with selected features from Deep learning-based (ResUNet) automated whole liver segmentations on MRI (T2FS and delayed enhanced-T1WI). The CoRC model incorporated radiomics scores and relevant clinical variables with logistic regression, comparing routine approaches. Diagnostic performance was evaluated by the area under the receiver operating characteristic curve (AUC). The additive value of the CoRC model to TE-LSM was investigated, considering necroinflammation. The CoRC model achieved AUCs of 0.79 (0.70, 0.86), 0.82 (0.73, 0.89), and 0.81 (0.72-0.91), outperformed FIB-4, APRI (all p < 0.05) in the internal, temporal, and external test sets and maintained the discriminatory power in G0-1 subgroups (AUCs range, 0.85-0.86; all p < 0.05). The AUCs of joint CoRC-LSM model were 0.86 (0.79-0.94), and 0.81 (0.72-0.90) in the internal and temporal sets (p = 0.01). The CoRC model was useful for triaging SF, and may add value to TE-LSM.

Diffusion kurtosis imaging for different brain masses characterization

BackgroundDiffusion kurtosis imaging is an advanced magnetic resonance imaging technique that reveals additional information on the microstructure and micro-dynamics of different brain masses without the need for contrast agents. The aim of this study was to provide a comprehensive analysis of the role of MRI diffusion kurtosis and to compare it with magnetic resonance spectroscopy (MRS) and dynamic susceptibility contrast perfusion (DSC) in characterizing different brain masses, including gliomas, recurrent tumors, radiation necrosis, abscesses, and infarctions. Sixty-six patients with intracranial brain masses were enrolled in this prospective study. All patients were examined by conventional MRI sequences, DSC perfusion, MRS, and diffusion kurtosis imaging, with implemented b values which were 200, 500, 1000, 1500 and 2000s/mm2.ResultsMean kurtosis (MK) was higher (P < 0.001) in recurrent brain tumors than in radiation-induced necrosis; the optimal MK cutoff value for differentiation between them was 642 with 91.3% sensitivity and 85.7% specificity. Mean kurtosis was also higher (P < 0.001) in high-grade gliomas than in low-grade gliomas; the optimal MK cutoff value for differentiation between them was 639 with 91.6% sensitivity and 85.71% specificity. There was a good level of agreement between ADC and MD within the studied cases, with a correlation coefficient r = 0.815. MK had more sensitivity and specificity in differentiation between high- and low-grade gliomas, as well as RIN and tumoral recurrence, than MRS and DSC.ConclusionsDiffusion kurtosis imaging stands as an integral, noninvasive, and noncontrast tool for the characterization of various brain masses. It augments the capabilities of traditional and advanced MRI techniques, providing a deeper understanding of the microstructural changes in brain tissues.

Native T1 Values are Elevated in Patients With Extra-Cardiac Sarcoid Without Conventional MRI Evidence of Cardiac Involvement

Native T1 Values are Elevated in Patients With Extra-Cardiac Sarcoid Without Conventional MRI Evidence of Cardiac Involvement

Differentiation of tuberculous and brucellar spondylitis using conventional MRI-based deep learning algorithms

PurposeTo investigate the feasibility of deep learning (DL) based on conventional MRI to differentiate tuberculous spondylitis (TS) from brucellar spondylitis (BS). MethodsA total of 383 patients with TS (n = 182) or BS (n = 201) were enrolled from April 2013 to May 2023 and randomly divided into training (n = 307) and validation (n = 76) sets. Sagittal T1WI, T2WI, and fat-suppressed (FS) T2WI images were used to construct single-sequence DL models and combined models based on VGG19, VGG16, ResNet18, and DenseNet121 network. The area under the receiver operating characteristic curve (AUC) was used to assess the classification performance. The AUC of DL models was compared with that of two radiologists with different levels of experience. ResultsThe AUCs based on VGG19, ResNet18, VGG16, and DenseNet121 ranged from 0.885 to 0.973, 0.873 to 0.944, 0.882 to 0.929, and 0.801 to 0.933, respectively, and VGG19 models performed better. The diagnostic efficiency of combined models outperformed single-sequence DL models. The combined model of T1WI, T2WI, and FS T2WI based on VGG19 achieved optimal performance, with an AUC of 0.973. In addition, the performance of all combined models based on T1WI, T2WI, and FS T2WI was better than that of two radiologists (P<0.05). ConclusionThe DL models have potential guiding value in the diagnosis of TS and BS based on conventional MRI and provide a certain reference for clinical work.

Diagnosing osteomyelitis in diabetic foot by diffusion-weighted imaging and dynamic contrast material-enhanced magnetic resonance imaging: a systematic review and meta-analysis

To evaluate the diagnostic performance of diffusion-weighted imaging (DWI) and dynamic contrast enhanced (DCE), for diagnosing osteomyelitis in the diabetic foot. A thorough search was carried out to identify suitable studies published up to September 2023. The quality of the studies involved was evaluated using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). The diagnostic sensitivity and specificity of each imaging modality/method for each specific cut point were summarized. The summary receiver operating characteristic (SROC) curve was calculated using bivariate mixed effects models. Five studies investigating 187 patients and 234 bone lesions with 110 diagnosed osteomyelitis were enrolled. Four studies used DWI (172 lesions), three studies used DCE techniques (140 lesions) and two studies presented results of conventional MRI (66 lesions). The sensitivity ranges using conventional MRI, DWI and DCE were 65%-100%, 65%-100% and 64%-100%, respectively. The specificity ranges were 50%-61%, 56%-95%, and 66%-93%, respectively. The SROC curve of DWI and DCE was 0.89 (95% CI, 0.86-0.92) and 0.90 (95% CI, 0.87-0.92), respectively. Combining DWI and DCE methods, alongside conventional MRI, can improve the reliability and accuracy of diabetic foot osteomyelitis diagnosis. However, the study recognizes result variability due to varying protocols and emphasizes the need for well-designed studies with standardized approaches. To optimize diagnostic performance, the study recommends considering low ADC values, Ktrans or rapid wash-in rate from DCE such as iAUC60, along with using large ROIs that cover the entire lesion while excluding normal bone marrow.

Clinical use of [18F]fluoro-ethyl-L-tyrosine PET co-registered with MRI for localizing prolactinoma remnants

PurposeTo assess the utility of [18F]fluoroethyl-L-tyrosine PET co-registered with magnetic resonance imaging ([18F]FET-PET/MRICR) in patients with difficult-to-localize prolactinoma to inform clinical decision-making and (surgical) treatment planning.MethodsRetrospective cohort study of 17 consecutive patients with prolactinoma undergoing [18F]FET-PET/MRICR between October 2020 and September 2022 for either (1) additional information in case of difficult-to-visualize remnants after prior transsphenoidal surgery (TSS), or pharmacological treatment, or (2) radiological diagnosis in absence of a (clear) adenoma on diagnostic/post-treatment conventional MRI.Results[18F]FET-PET/MRICR identified a lesion in 14/17 patients, yet failed to identify active lesions in 2 patients with negative conventional MRI despite prolactin > 7.5 times upper limit of normal. [18F]FET-PET/MRICR results were inconclusive in 1 patient due to diffuse tracer uptake 10 weeks post-surgery. [18F]FET-PET/MRICR was completely concordant with a suspected lesion on conventional MRI in 10/17 patients, and partially concordant in 3/17 patients. New foci were identified in 4/17 patients. The [18F]FET-PET/MRICR conclusions influenced clinical shared decision-making in 15/17 patients, of whom 7 patients underwent TSS and 8 refrained from TSS. One patient underwent TSS despite negative [18F]FET-PET/MRICR, and one patient underwent additional imaging. Intraoperative findings corresponded with [18F]FET-PET/MRICR in 5/8 patients, and immunohistochemistry was positive in 5/8 patients. The treatment goal was achieved in 7/8 patients, and remission was achieved in 5/7 patients in whom total resection was considered feasible.Conclusion[18F]FET-PET/MRICR can be of added value in the preoperative decision-making process for selected patients with difficult-to-localize prolactinoma (remnants), or patients lacking a substrate on conventional MRI.

Fractional tumor burden maps increase the confidence of reading brain MR perfusion

Rationale and objectivesVarious methods exist to perform and post-process perfusion weighted MR imaging in the post-treatment imaging of glioma patients to differentiate tumor progression from tumor-related abnormalities. One of these post-processing methods produces ‘fractional tumor burden’ maps. This multi-reader study investigated the clinical feasibility of fractional tumor burden maps on real world data from radiological follow-up of high-grade astrocytoma patients. MethodsFive readers with background in radiology and varying levels of experience were tasked with assessing 30 astrocytoma and glioblastoma patients during one reader session. First, they were provided with a dataset of conventional MRI sequences, including perfusion MRI with regional cerebral blood volume maps. Then the dataset was expanded with a corresponding fractional tumor burden maps. Diagnostic accuracy, duration of post-processing, duration of the assessment of the fractional tumor burden maps, the diagnostic confidence reported by the readers and their diagnoses were recorded. Final diagnosis was determined by clinical and radiological follow-up and/or histopathological data used as gold standard. ResultsA mean sensitivity of 83.3 % and mean specificity of 55.1 % was obtained without the use of fractional tumor burden maps, whereas their additional of fractional tumor burden maps resulted in a mean sensitivity and specificity of 79.5 % and 54.2 %, respectively. Diagnostic accuracies with and without fractional tumor burden maps were not significantly different (Z = 0.76, p = 0.450). The median time spent post-processing was 313 s, while the median duration of the assessment of the FTB maps was 19 s. Interestingly, reader confidence increased significantly after adding the fractional tumor burden-maps to the assessment (Z = 454, p < 0.01). ConclusionsWhile the use of fractional tumor burden maps does not carry additional value in the radiological follow-up of post-operative high-grade astrocytoma and glioblastoma patients, it does give readers more confidence in their diagnosis.

Abbreviated MRI in the evaluation of dizziness: report turnaround times and impact on length of stay compared to CT, CTA, and conventional MRI.

Neuroimaging is often used in the emergency department (ED) to evaluate for posterior circulation strokes in patients with dizziness, commonly with CT/CTA due to speed and availability. Although MRI offers more sensitive evaluation, it is less commonly used, in part due to slower turnaround times. We assess the potential for abbreviated MRI to improve reporting times and impact on length of stay (LOS) compared to conventional MRI (as well as CT/CTA) in the evaluation of acute dizziness. We performed a retrospective analysis of length of stay via LASSO regression for patients presenting to the ED with dizziness and discharged directly from the ED over 4 years (1/1/2018-12/31/2021), controlling for numerous patient-level and logistical factors. We additionally assessed turnaround time between order and final report for various imaging modalities. 14,204 patients were included in our analysis. Turnaround time for abbreviated MRI was significantly lower than for conventional MRI (4.40h vs. 6.14h, p < 0.001) with decreased impact on LOS (0.58h vs. 2.02h). Abbreviated MRI studies had longer turnaround time (4.40h vs. 1.41h, p < 0.001) and was associated with greater impact on ED LOS than non-contrast CT head (0.58h vs. 0.00h), however there was no significant difference in turnaround time compared to CTA head and neck (4.40h vs. 3.86h, p = 0.06) with similar effect on LOS (0.58h vs. 0.53h). Ordering both CTA and conventional MRI was associated with a greater-than-linear increase in LOS (additional 0.37h); the same trend was not seen combining CTA and abbreviated MRI (additional 0.00h). In the acute settings where MRI is available, abbreviated MRI protocols may improve turnaround times and LOS compared to conventional MRI protocols. Since recent guidelines recommend MRI over CT in the evaluation of dizziness, implementation of abbreviated MRI protocols has the potential to facilitate rapid access to preferred imaging, while minimizing impact on ED workflows.

Histomolecular Validation of [18F]-FACBC in Gliomas Using Image-Localized Biopsies.

Gliomas have a heterogeneous nature, and identifying the most aggressive parts of the tumor and defining tumor borders are important for histomolecular diagnosis, surgical resection, and radiation therapy planning. This study evaluated [18F]-FACBC PET for glioma tissue classification. Pre-surgical [18F]-FACBC PET/MR images were used during surgery and image-localized biopsy sampling in patients with high- and low-grade glioma. TBR was compared to histomolecular results to determine optimal threshold values, sensitivity, specificity, and AUC values for the classification of tumor tissue. Additionally, PET volumes were determined in patients with glioblastoma based on the optimal threshold. [18F]-FACBC PET volumes and diagnostic accuracy were compared to ce-T1 MRI. In total, 48 biopsies from 17 patients were analyzed. [18F]-FACBC had low uptake in non-glioblastoma tumors, but overall higher sensitivity and specificity for the classification of tumor tissue (0.63 and 0.57) than ce-T1 MRI (0.24 and 0.43). Additionally, [18F]-FACBC TBR was an excellent classifier for IDH1-wildtype tumor tissue (AUC: 0.83, 95% CI: 0.71-0.96). In glioblastoma patients, PET tumor volumes were on average eight times larger than ce-T1 MRI volumes and included 87.5% of tumor-positive biopsies compared to 31.5% for ce-T1 MRI. The addition of [18F]-FACBC PET to conventional MRI could improve tumor classification and volume delineation.

Ultrafast sequence-based prediction model and nomogram to differentiate additional suspicious lesions on preoperative breast MRI.

To investigate whether ultrafast sequence improves the diagnostic performance of conventional dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in differentiating additional suspicious lesions (ASLs) on preoperative breast MRI. A retrospective database search identified 668 consecutive patients who underwent preoperative breast DCE-MRI with ultrafast sequence between June 2020 and July 2021. Among these, 107 ASLs from 98 patients with breast cancer (36 multifocal, 42 multicentric, and 29 contralateral) were identified. Clinical, pathological, conventional MRI findings, and ultrafast sequence-derived parameters were collected. A prediction model that adds ultrafast sequence-derived parameters to clinical, pathological, and conventional MRI findings was developed and validated internally. Decision curve analysis and net reclassification index statistics were performed. A nomogram was constructed. The ultrafast model adding time to peak enhancement, time to enhancement, and maximum slope showed a significantly increased area under the receiver operating characteristic curve compared with the conventional model which includes age, human epidermal growth factor receptor 2 expression of index cancer, size of index cancer, lesion type of index cancer, location of ASL, and size of ASL (0.92 vs. 0.82; p = 0.002). The decision curve analysis showed that the ultrafast model had a higher overall net benefit than the conventional model. The net reclassification index of ultrafast model was 23.3% (p = 0.001). A combination of ultrafast sequence-derived parameters with clinical, pathological, and conventional MRI findings can aid in the differentiation of ASL on preoperative breast MRI. Our prediction model and nomogram that was based on ultrafast sequence-derived parameters could help radiologists differentiate ASLs on preoperative breast MRI. Ultrafast MRI can diminish background parenchymal enhancement and possibly improve diagnostic accuracy for additional suspicious lesions (ASLs). Locationof ASL, larger size of ASL, and highermaximum slope were associated with malignant ASL. The ultrafast model and nomogram can help preoperatively differentiate additional malignancies.

The Diagnostic Value of Conventional MRI Combined With Diffusion-Weighted Imaging in Microprolactinomas.

Turbo spin-echo (TSE) diffusion-weighted imaging (DWI) sequences may reduce susceptibility artifacts and image distortion in sellar region, allowing better visualization of small pituitary lesions, and may be used to assist in the diagnosis of pituitary microadenomas. To explore the application value of conventional MRI combined with DWI sequences in the diagnosis of microprolactinomas. Prospective. Thirty-four patients in microprolactinomas with high signal on T2WI (HT2-PRL) group (34 females, 34 ± 7 years), 26 patients in microprolactinomas with equal or low signal on T2WI (ELT2-PRL) group (21 females, 34 ± 7 years), 35 patients with hyperprolactinemia (33 females, 32 ± 8 years), and 30 normal controls (25 females, 31 ± 7 years). TSE sequence at 3 T. Pituitary morphological parameters (such as length and volume), dynamic contrast-enhanced parameters (such as time to peak) and the apparent diffusion coefficients (ADCs) were measured in each group. ANOVA and Mann-Whitney U test were used to compare parameters among groups. Spearman's coefficient was used to evaluate the correlation between variables. ROC analysis was used to assess the performance of the parameters. A P-value <0.05 was considered statistically significant. The pituitary volume of patients in HT2-PRL, ELT2-PRL, and hyperprolactinemia group were 831.00 (747.60, 887.60), 923.63 ± 219.34, and 737.20 (606.40, 836.80) mm3. The pituitary maximum height in these three groups were 7.03 (6.43, 8.63), 8.03 ± 1.41, and 6.63 ± 1.28 mm, respectively. The lesion ADC value was significantly correlated with T2 relative signal intensity (the ratio of signal intensity of microprolactinoma or anterior pituitary to left temporal cortex) (r = 0.821). Compared with patients with hyperprolactinemia, the diagnostic efficacy of T2 relative signal intensity was higher in HT2-PRL group, with an AUC of 0.954, whereas the ADC value was the highest in ELT2-PRL group, with an AUC of 0.924. DWI sequences can be used to assist in the diagnosis of pituitary microadenomas. 1 TECHNICAL EFFICACY: Stage 2.

A visual marker for early atrophy of the supraspinatus muscle on conventional MRI: introduction of the blackbird sign.

The aim of this study was to introduce the blackbird sign as a fast, qualitative measure of early supraspinatus (SSP) muscle atrophy and to correlate the sign with quantitatively assessed muscle volume and intramuscular fat fraction (FF) in patients with full-thickness SSP tears. The blackbird sign describes the asymmetric pattern of early SSP atrophy: on sagittal MR images, the supero-posterior contour of the muscle becomes concave, resembling the shape of a blackbird. MRIs of patients with full-thickness SSP tears were retrospectively reviewed for the presence of the blackbird and tangent signs. Patients were then divided into group 1: negative tangent sign and negative blackbird sign (n = 67), group 2: negative tangent sign and positive blackbird sign (n = 31), and group 3: positive tangent sign (n = 32). A 2-point Dixon sequence was acquired in all patients from which quantitative FF and muscle volumes were calculated. In total 130 patients (mean age 67 ± 11 years) were included. Mean SSP volume was significantly smaller in group 3 (15.8 ± 8.1 cm3) compared to group 2 (23.9 ± 7.0 cm3, p = 0.01) and group 1 (29.7 ± 9.1 cm3, p < 0.01). Significantly lower muscle volumes were also found in group 2 compared to group 1 (p = 0.02), confirming that the blackbird sign is able to identify early SSP atrophy. Mean FF in the SSP was significantly higher in group 3 (18.5 ± 4.4%) compared to group 2 (10.9 ± 4.7%, p < 0.01) and group 1 (6.1 ± 2.6%, p < 0.01). Visual assessment of early muscle atrophy of the SSP is feasible and reproducible using the blackbird sign, allowing the diagnosis of early SSP atrophy. In routine clinical practice, the blackbird sign may be a useful tool for assessing early muscle degeneration before the risk of postoperative rotator cuff re-tears increases with progressive muscle atrophy and fatty infiltration. Quantitative measurements of rotator cuff injuries require time, limiting clinical practicality. The proposed blackbird sign is able to identify early SSP atrophy. Reader agreement for the blackbird sign was substantial, demonstrating reproducibility and ease of implementation in the clinical routine.

DCE-MRI to distinguish all monoclonal plasma cell disease stages and correlation with diffusion-weighted MRI/PET-based biomarkers in a hybrid simultaneous whole body-2-[18F]FDG-PET/MRI imaging approach

BackgroundDynamic contrast-enhanced-MRI (DCE-MRI) is able to study bone marrow angiogenesis in patients with multiple myeloma (MM) and asymptomatic precursor diseases but its role in the management of MM has not yet been established. The aims of this prospective study was to compare DCE-MRI-based parameters between all monoclonal plasma cell disease stages in order to find out discriminatory parameters and to seek correlations with other diffusion-weighted MRI and positron emission tomography (PET)-based biomarkers in a hybrid simultaneous whole-body-2-[18F]fluorodeoxyglucose (FDG)-PET/MRI (WB-2-[18F]FDG-PET/MRI) imaging approach.MethodsPatients with newly diagnosed Monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM) or symptomatic MM according to international myeloma working group and underwent WB-2-[18F]FDG-PET/MRI imaging including bone marrow DCE sequences at the Nantes University Hospital were prospectively enrolled in this study before receiving treatment.ResultsOne hundred and sixty-seven patients (N = 167, mean age: 64 years ± 11 [Standard deviation], 66 males) were considered for the analysis. DCE-MRI-based Peak Enhancement Intensity (PEI), Time to PEI (TPEI) and their maximum intensity time ratio (MITR: PEI/TPEI) values were significantly different between the different monoclonal plasma cell disease stages, PEI values increasing and TPEI values decreasing progressively along the spectrum of plasma cell disorders, from MGUS stage to symptomatic multiple myeloma. PEI values were significantly higher in patients with diffuse bone marrow involvement (either in PET or in MRI images) than in those without diffuse bone marrow involvement, unlike TPEI values. PEI and TPEI values were not significantly different between patients with or without focal bone lesions.ConclusionDifferent DCE-MRI-based parameters (PEI, TPEI, MITR) could significantly differentiate all monoclonal plasma cell disease stages and complemented conventional MRI and PET-based biomarkers.

Role of MRI in Assessment of Central Nervous System Lesions and Post Treatment Complications in Pediatric Patents with Leukemia

Abstract Background In terms of pediatric oncology, leukemia is one of the most frequent deadly illnesses. Early CNS problem identification and appropriate therapy were enhanced by MRI. Aim Describe the MRI results brought on by leukemia's involvement in CNS structures and treatment-related CNS side effects, and evaluate their efficacy for early therapy and preventing long-term adverse effects. Patients and Methods A prospective observational study included 52 children with leukemia. All patients undergone MR examination including conventional MRI, MR diffusion imaging and MR venography (MRV). Results Regarding MRI finding of CNS, leukemic infiltration was found in 57.7%, sub volimic changes in mild manner in 50% and about 26% in a moderate manner while absent in 23.1%, PRES was present in 19.2%, venous thrombosis present in 30.8% and post treatment complications were found in 7.7%. Conclusion Diffusion-weighted MRI proved very helpful in the early diagnosis and distinction of various CNS lesions seen in young patients with leukemia and post-treatment CNS sequelae. These techniques included conventional, post- contrast, MR venography, and diffusion-weighted MRI.