Multicenter Evaluation of AI-generated DIR and PSIR for Cortical andJuxtacortical Multiple Sclerosis Lesion Detection

To prospectively perform a direct measurement of fractional anisotropy (FA) and mean diffusivity (MD) in cortical lesions of patients with multiple sclerosis (MS). The study was approved by the institutional review board and was HIPAA compliant; informed consent was obtained. Magnetic resonance (MR) images, including double inversion-recovery (DIR), phase-sensitive inversion-recovery (PSIR), and diffusion-tensor images, were acquired from nine MS patients with cortical lesions (five women, four men; median age, 47 years) and nine age- and sex-matched volunteer control subjects. Following nonlinear elastically constrained image registration for aligning diffusion-weighted images to DIR images, maps of FA and MD were computed for each subject. Cortical lesions were identified on DIR images and validated by using PSIR images. The diffusion-tensor imaging maps were then overlaid on the coregistered DIR images, and mean FA and MD values were measured in regions of interest drawn on the cortical lesions. Differences between normal gray matter (GM) and cortical lesions were evaluated by using the generalized estimating equation. FA and MD histograms of whole brain and GM (global analysis) in healthy control subjects and MS patients were also computed for comparison with those in previously published studies. FA and MD values were significantly higher in cortical lesions compared with similar regions in healthy control subjects. Histogram peak FA was significantly decreased and peak MD was significantly increased in patients relative to control subjects. DIR and PSIR combined with nonlinear image registration allowed direct focal measurement of FA and MD in cortical lesions.

Background and purposeSynthetic MR imaging (SyMRI) allows the reconstruction of various contrast images, including double inversion recovery (DIR), from a single scan. This study aimed to investigate the advantages of SyMRI by comparing synthetic DIR images with synthetic T2-weighted fluid-attenuated inversion recovery (T2W-FLAIR) and conventional DIR images.Materials and methodsWe retrospectively reviewed the imaging data of 100 consecutive patients who underwent brain MRI between December 2018 and March 2019. Synthetic DIR, T2W-FLAIR, T1-weighted, and phase-sensitive inversion recovery (PSIR) images were generated from SyMRI data. For synthetic DIR, the two inversion times required to suppress white matter and cerebrospinal fluid (CSF) were manually determined by two radiologists. Quantitative analysis was performed by manually tracing the region of interest (ROI) at the sites of the lesion, white matter, and CSF. Synthetic DIR, synthetic T2W-FLAIR, and conventional DIR images were compared on the basis of using the gray matter-to-white matter, lesion-to-white matter, and lesion-to-CSF contrast-to-noise ratios.ResultsThe two radiologists showed no differences in setting inversion time (TI) values, and their evaluations showed excellent interobserver agreement. The mean signal intensities obtained with synthetic DIR were significantly higher than those obtained with synthetic T2W-FLAIR and conventional DIR.ConclusionSynthetic DIR images showed a higher contrast than synthetic T2WFLAIR and conventional DIR images.

IntroductionLate gadolinium enhancement (LGE) imaging with cardiovascular magnetic resonance (CMR) is considered the non-invasive gold standard for identifying and quantifying myocardial scar. The diagnostic and prognostic importance of myocardial scar...

The aim of our study is to evaluate the diagnostic accuracy of double inversion recovery (DIR) in detection of multiple sclerosis (MS) lesions as well as the correlation between the expanded disability status scale (EDSS) and lesion load measurement detected by DIR, fluid attenuated inversion recovery (FLAIR) and T2 weighted imaging (T2WI) in order to reveal the essential role of DIR sequence in assessing clinical inability as a practicable experiment. A total of 97 patients were assessed on a 3T Siemens Skyra MRI scanner using DIR, FLAIR, and T2W_TSE sequences. EDSS was used to assess the physical disability in patients with MS. The diagnostic accuracy of DIR, FLAIR and T2WI sequences was also determined in different anatomical regions. Sensitivity and specificity were assessed by relative operating characteristics/ receiver operating characteristics (ROC) curve at different cut off points. Spearman correlation was applied to identify the significant relationships between the number of lesions displayed by DIR, FLAIR and T2WI at different regions and EDSS score. Our results pointed out the highest sensitivity (92.9%) and specificity (73.5%) for the number of lesions in infratentorial region at the cut-off point of 4.5 and the highest correlation between the number of lesions and EDSS was observed in infratentorial region (r= 0.584, p<0.001) for DIR sequence. According to the findings of ROC analysis, the number of lesions detected by DIR technique in the infratentorial region is the best predictor of EDSS as a gold standard. DIR can be used as a complementary technique comparing to conventional T2 and FLAIR sequences and describe physical and cognitive dysfunction as well. Due to the higher potential of the DIR sequence to reveal a greater number of MS lesions and to overcome the technical defect of conventional MRI sequences in the diagnosis of cortical lesions, it is recommended that DIR sequences be routinely added to MRI imaging protocols for patients with MS.

Motivation: Accurate detection of juxtacortical lesions in MS within a clinically feasible timeframe remains challenging due to the long scan times required by 3D double inversion recovery (DIR) imaging. Goal(s): This study aimed to evaluate the efficacy of high-resolution DIR imaging enabled by the new deep learning-based technique, DL-Speed (DLS-DIR). Approach: The study conducted a retrospective analysis of MRI data from 25 MS patients using C-DIR and DLS-DIR. Two neuroradiologists independently assessed juxtacortical lesions, comparing lesion counts across methods and calculating interobserver agreement. Results: DLS-DIR significantly outperformed C-DIR, especially in detecting cortical MS lesions, within a clinically acceptable acquisition time. Impact: 3D DL-Speed double inversion recovery imaging is acquired in 4:23 with 0.7mm isotropic resolution covering the whole brain, which could improve the accuracy of cortical lesion assessment in patients with multiple sclerosis.

The precise location of multiple sclerosis (MS) cortical lesions can be very challenging at 3 T, yet distinguishing them from subcortical lesions is essential for the diagnosis and prognosis of the disease. Compressed sensing-accelerated fluid and white matter suppression imaging (CS-FLAWS) is a new magnetic resonance imaging sequence derived from magnetization-prepared 2 rapid acquisition gradient echo with promising features for the detection and classification of MS lesions. The objective of this study was to compare the diagnostic performances of CS-FLAWS (evaluated imaging) and phase sensitive inversion recovery (PSIR; reference imaging) for classification of cortical lesions (primary objective) and infratentorial lesions (secondary objective) in MS, in combination with 3-dimensional (3D) double inversion recovery (DIR). Prospective 3 T scans (MS first diagnosis or follow-up) acquired between March and August 2021 were retrospectively analyzed. All underwent 3D CS-FLAWS, axial 2D PSIR, and 3D DIR. Double-blinded reading sessions exclusively in axial plane and final consensual reading were performed to assess the number of cortical and infratentorial lesions. Wilcoxon test was used to compare the 2 imaging datasets (FLAWS + DIR and PSIR + DIR), and intraobserver and interobserver agreement was assessed using the intraclass correlation coefficient. Forty-two patients were analyzed (38 with relapsing-remitting MS, 29 women, 42.7 ± 12.6 years old). Compressed sensing-accelerated FLAWS allowed the identification of 263 cortical lesions versus 251 with PSIR ( P = 0.74) and 123 infratentorial lesions versus 109 with PSIR ( P = 0.63), corresponding to a nonsignificant difference between the 2 sequences. Compressed sensing-accelerated FLAWS exhibited fewer false-negative findings than PSIR either for cortical lesions (1 vs 13; P < 0.01) or infratentorial lesions (1 vs 15; P < 0.01). No false-positive findings were found with any of the 2 sequences. Diagnostic confidence was high for each contrast. Three-dimensional CS-FLAWS is as accurate as 2D PSIR imaging for classification of cortical and infratentorial MS lesions, with fewer false-negative findings, opening the way to a reliable full brain MS exploration in a clinically acceptable duration (5 minutes 15 seconds).

Objective: To classify spinal cord lesions in multiple sclerosis (MS) based on white matter (WM) columns, and grey matter (GM) and WM involvement using magnetic resonance imaging (MRI). Background The localization of spinal cord lesions has not been well documented on MRI, although morphology and distribution of plaques have been characterized in post-mortem studies. Design/Methods: MRI was performed on the cervical cord in 16 MS patients (10 female, mean age 44.8) (8 relapsing remitting (RR) MS, 7 secondary progressive (SP) MS, 1 clinically isolated syndrome (CIS)). Axial phase sensitive inversion recovery (PSIR) and gradient-echo sequences were acquired. Two readers reviewed both images simultaneously and reached a consensus about classification of lesions by location: anterior (AC), lateral (LC) or posterior columns (PC). A sub-classification of lesions in mixed WM/GM and those involving WM only was also performed. Lesions were outlined manually on PSIR images and compared with mean cord area. Results: 51 lesions were identified, 24 in RRMS, 22 in SPMS, 5 in CIS. Three lesions were seen in AC (5.8%), 18 in PC (35.3%) and 30 in LC (58.9%). 33% of lesions involved WM alone and 67% involved both GM and WM; no pure GM lesions were identified. Mean lesion area in AC was 4.3mm2, LC 8.5mm2, PC 11.3mm2, with lesions in each column covering 6.1%, 12% and 16.1% of mean cord area respectively, mean lesion length in AC 18.3mm, LC 17.6mm and PC 24.8mm. Conclusions: Most lesions seen involved GM and WM, and were in the PC and LC, in agreement with post-mortem studies. However, no pure GM lesions were seen, suggesting technical limitations or a difference in patient characteristics from post-mortem studies. MRI may permit classification of spinal cord lesion location, area and length, which maybe correlated in future with disability to provide new insights into their functional effects. Supported by: MS Society. Disclosure: Dr. Kearney has nothing to disclose. Dr. Miszkiel has received research support from Biogen Idec and GlaxoSmithKline, Inc. Dr. Yiannakas has nothing to disclose. Dr. Ciccarelli has nothing to disclose. Dr. Miller has received personal compensation for activities with UCL Institute of Neurology, Biogen Idec, GlaxoSmithKline, and Bayer Schering Pharma. Dr. Miller has received personal compensation in an editorial capacity for Journal of Neurology. Dr. Miller has received research support from GlaxoSmithKline, Biogen Idec, and Novartis.

Multiple system atrophy (MSA) is a neurodegenerative disorder that presents as parkinsonism, cerebellar ataxia, and autonomic dysfunction. Magnetic resonance imaging (MRI) findings of MSA are reported to be the atrophy of the putamen/pons/cerebellum, hot cross bun sign, and bright middle cerebellar peduncle (MCP) sign. Here, we assessed the sensitivity of detecting the bright MCP sign in patients with MSA cerebellar variant (MSA-C) using a double inversion recovery (DIR) procedure, comparing it to the sensitivity of detection by T2-weighted image (T2WI) and fluid-attenuated inversion recovery (FLAIR) sequences on conventional MRI. We evaluated 6 MSA-C patients and 6 control patients (multiple sclerosis, neuromyelitis optica, and spinocerebellar atrophy). Characteristics of all the patients were collected, and MRI was analyzed. Two neurologists independently evaluated the visualization of the bright MCP sign using a 4-point visual grade from Grade 0 to Grade 3. Differences in grade between DIR and T2WI or FLAIR were statistically analyzed. Also, as a quantitative analysis, the signal intensity of the MCP lesion was compared with that of the ipsilateral thalamus, and the MCP/thalamus ratio was evaluated. As a result, DIR more sensitively showed the bright MCP signs of MSA-C patients than T2WI or FLAIR. Also, the bright MCP sign deteriorated and expanded over time in the cases we followed with MRI. We also evaluated hot cross bun sign in the pons, but the hot cross bun sign in MSA-C patients was not significantly different between the DIR and conventional MRI sequences. The DIR procedure can be a more sensitive method for detecting the involvement of MCP lesions in MSA-C.

ObjectiveAccurate identification and localization of cortical gray matter (CGM) lesions in MS is important when determining their clinical relevance. Double inversion recovery (DIR) scans have been widely used to detect MS CGM lesions. Phase sensitive inversion recovery (PSIR) scans have a higher signal to noise, and can therefore be obtained at a higher resolution within clinically acceptable times. This enables detection of more CGM lesions depicting a clearer cortical and juxtacortical anatomy. In this study, we systematically investigated if the use of high resolution PSIR scans changes the classification of CGM lesions, when compared with standard resolution DIR scans.Methods60 patients [30 RR(Relapsing remitting) and 15 each with PP(Primary progressive) and SP(Secondary progressive) MS] were scanned on a 3T Philips Achieva MRI scanner. Images acquired included DIR (1×1×3 mm resolution) and PSIR (0.5×0.5×2 mm). CGM lesions were detected and classified on DIR as intracortical (IC) or leucocortical (LC). We then examined these lesions on corresponding slices of the high resolution PSIR scans and categorized them as IC, LC, Juxtacortical white matter (JC-WM, abutting but not entering cortex) and other white matter (WM, not juxtacortical). Classifications using both scans were noted.Results282 IC and 483 LC were identified on DIR. Of the IC lesions, 61% were confirmed as IC on PSIR, 35.5% were reclassified as LC and 3.5% as JC-WM or other WM only. Of the LC DIR lesions, 43.9% were confirmed at LC on PSIR, 16.1% were reclassified as IC and 40% as JC-WM or other WM only. Overall, 50% (381/765) of CGM lesions seen on DIR were reclassified, and 26.5% (203/765) affected WM only.ConclusionsWhen compared with higher resolution PSIR, a significant proportion of lesions classified as involving CGM on DIR appear to either contain more white matter than expected or to not involve CGM at all.

Double inversion recovery (DIR) MRI is a relatively novel imaging technique in which both white matter (WM) and CSF signals are suppressed; cortical lesions are thereby identified as focal areas of hyperintensity relative to surrounding gray matter (GM).1 Three dimensional DIR increases intracortical lesion detection by 500% compared to lesion identification on T2-weighted spin-echo, and by more than 150% when compared to 3D fluid-attenuated inversion recovery (FLAIR).1 Despite these improvements, DIR-detected lesions are fewer than expected based on postmortem studies2: less than 7 (on average) per patient in relapsing-remitting (RR), primary progressive (PP), and secondary progressive (SP) multiple sclerosis (MS).3,–,5 This low rate of detection could be due to technical factors, such as low signal-to-noise ratio, poor definition of lesion boundaries, and the high likelihood of artifacts (e.g., flow, signal intensity differences between slabs, and vessel hyperintensities). It is not easy to see cortical lesions on DIR images, and even when following the conservative international recommendations on lesion scoring (subpial lesions are excluded), experts reached complete agreement in only 19% of the lesions scored.6 Why have these challenges and limitations not discouraged the use of DIR in clinical studies? The short answer is that there is a …

The objective of the study was to examine the utility of double inversion recovery (DIR) magnetic resonance imaging (MRI) using a 3-T magnetic resonance imager in the preoperative evaluation of hippocampal sclerosis (HS) in patients with mesial temporal lobe epilepsy. This retrospective study had institutional review board approval, and informed consent was obtained. Twelve patients with unilateral HS and 12 age-matched healthy control subjects were included. Imaging was performed using DIR, fluid-attenuated inversion recovery (FLAIR), and T2-weighted turbo spin-echo (T2 TSE) sequences vertical to the hippocampal axis. Quantitative assessment for hippocampus of the patients and control subjects was determined. Regions of interest (ROIs) were placed on bilateral hippocampi, and signal intensity was measured. The signal-to-noise ratio (SNR) of ipsilateral hippocampus, contrast ratio of ipsilateral-to-contralateral side, contrast-to-noise ratio (CNR), and asymmetry index of bilateral hippocampi were calculated and compared among the 3 sequences. Statistical analyses were performed with 1-way analysis of variance and Student t test. On DIR images, HS demonstrated extremely high signal intensity. The hippocampi ipsilateral to the seizure focus showed significantly increased signal intensity, as compared with contralateral hippocampi and healthy subjects (F = 47.876, P < 0.001). The higher SNR of ipsilateral hippocampus on DIR was significant compared with the FLAIR and T2 TSE (P < 0.01). The CNR of bilateral hippocampi on DIR was also significantly higher than that on the FLAIR and T2 TSE (P < 0.01). However, compared with the FLAIR, no significant differences of contrast ratio and asymmetry index between bilateral hippocampi were observed on DIR. Double inversion recovery brain imaging reveals characteristically extremely high signal intensity of hippocampus in patients with HS. Double inversion recovery images can describe HS with high SNR and CNR superior to conventional magnetic resonance sequences and can be valuable for the diagnosis of HS.

Myocardial motion-corrected phase-sensitive inversion recovery late gadolinium enhancement in free breathing paediatric patients: a comparison with single-shot coherent gradient echo (“TrueFISP”) phase-sensitive inversion recovery

Phase enhanced PSIR T1 weighted imaging improves contrast resolution of the nucleus basalis of Meynert at 7 T: a preliminary study

To describe a referenceless reconstruction approach to generate phase-sensitive inversion recovery images without relying on the extra acquisition of reference images. The basic idea of the Referenceless Acquisition of Phase-sensitive Inversion-recovery with Decisive reconstruction, or RAPID, algorithm is to retrieve the magnetization polarity by estimating the background phase variation of a complex valued image. The theory and algorithm of RAPID is described in detail. To evaluate the performance of RAPID, seven patients were recruited then scanned in different anatomical regions (cardiac, brain, and vascular). Standard Phase Sensitive Inversion Recovery (PSIR) reconstructions using reference image information were compared with RAPID reconstructions using the same source data. RAPID reconstructed images were found to provide very good agreement with PSIR reconstructed images on all cases, although no reference image info was used in the RAPID algorithm. For neuroimaging applications, it was found that RAPID reconstruction is more robust compared with the PSIR algorithm as RAPID can avoid potential errors introduced by the reference acquisition. The RAPID technique for phase-sensitive reconstruction is promising and can improve the imaging efficiency by a factor of 2 compared with PSIR. RAPID was also shown to provide more robust reconstruction by avoiding errors caused by the reference acquisition.

Late gadolinium enhancement cardiac MR (LGE-CMR) and extracellular volume fraction (ECV-CMR) are widely used to evaluate macroscopic and microscopic myocardial fibrosis. Macrocyclic contrast media are increasingly used off-label for myocardial scar assessment, given the superior safety profile of these agents. We aimed to assess the performance of two macrocyclic contrast agents, gadoterate meglumine and gadobutrol, for the evaluation of myocardial scar. Forty subjects (61 ± 11years, 67.5% men) who underwent LGE-CMR using gadobutrol were prospectively recruited for a research CMR scan using same-dose gadoterate meglumine (0.2mmol/kg) at 1.5T. Myocardial scar quantification was performed using a short-axis phase-sensitive inversion recovery (PSIR) Turbo-FLASH and steady-state free precession (SSFP) images. Pre- and post-contrast T1-mapping was employed to assess myocardial ECV. An intraclass correlation coefficient (ICC) was used to check for reliability between the two contrast agents. Using manual thresholding on PSIR Turbo-FLASH images, mean LGE scar percentage (LGE%) was 9.9 ± 9.7% and 9.4 ± 9.7% for gadobutrol and gadoterate meglumine, respectively (p > 0.05) (ICC: 0.99, 95% CI: 0.97-0.99). Using the PSIR SSFP technique and manual thresholding, LGE% averaged 7.5 ± 9.0% and 7.1 ± 8.6% for gadobutrol and gadoterate meglumine, respectively (p > 0.05) (ICC: 0.99, 95% CI: 0.98-0.99). Average ECV with gadobutrol and gadoterate meglumine were similar at 28.40 ± 4.88 and 28.46 ± 4.73 (p > 0.05) with a strong correlation (ICC: 0.98, 95% CI: 0.94-0.99). We found LGE- and ECV-CMR values derived from gadoterate meglumine comparable to values derived from gadobutrol. Gadoterate meglumine has a comparable performance to gadobutrol in identifying LGE-derived myocardial scar both qualitatively and quantitatively. • Late gadolinium-enhancement cardiac MR (LGE-MR) and extracellular volume (ECV) fraction are widely used to evaluate macroscopic and microscopic myocardial fibrosis. • Macrocyclic contrast media are increasingly used off-label for myocardial scar assessment, given the presumed superior safety profile of these agents. • LGE- and ECV-CMR values derived from gadoterate meglumine are comparable to values derived from gadobutrol.