Pre- and Postcontrast 3D Double Inversion Recovery Sequence in Multiple Sclerosis: A Simple and Effective MR Imaging Protocol

Predicting the apolipoprotein E ε4 allele carrier status based on gray matter volumes and cognitive function

BACKGROUND

Apolipoprotein E (ApoE) ε4 carriers have a higher risk of developing Alzheimer's disease (AD) and show brain atrophy and cognitive decline even before diagnosis.

OBJECTIVE

To predict ApoE ε4 status using gray matter volume (GMV) obtained from magnetic resonance imaging images and demographic data with machine learning (ML) methods.

METHODS

We recruited 74 participants (25 probable AD, 24 amnestic mild cognitive impairment, and 25 cognitively normal older people) with known ApoE genotype (22 ApoE ε4 carriers and 52 noncarriers) and scanned them with three-dimensional (3D) T1-weighted (T1W) and 3D double inversion recovery (DIR) sequences. We extracted GMV from regions of interest related to AD pathology and used them as features along with age and mini-mental state examination (MMSE) scores to train different ML models. We performed both receiver operating characteristic curve analysis and the prediction analysis of the ApoE ε4 carrier with different ML models.

RESULTS

The best model of ML analyses was a cubic support vector machine (SVM3) that used age, the MMSE score, and DIR GMVs at the amygdala, hippocampus, and precuneus as features (AUC = .88). This model outperformed models using T1W GMV or demographic data alone.

CONCLUSION

Our results suggest that brain atrophy with DIR GMV and cognitive decline with aging can be useful biomarkers for predicting ApoE ε4 status and identifying individuals at risk of AD progression.

Contrast-enhanced double inversion recovery sequence for patients with multiple sclerosis: feasibility of subtraction images between pre- and post-contrast images

BACKGROUND

Few reports have examined the feasibility of a post-contrast double inversion recovery (DIR) magnetic resonance (MR) sequence in patients with multiple sclerosis (MS) because of partial or complete signal loss of enhancing MS lesions.

PURPOSE

To compare subtracted images of DIR (pre-contrast - post-contrast DIR images) with contrast enhanced T1-weighted (CE-T1W) images in the depiction of contrast enhancement of MS lesions.

MATERIAL AND METHODS

In total, 27 patients were included. Two neuroradiologists interpreted both images of CE-T1W imaging and subtracted DIR, and interpretation of the images was classified into a score of 1-5 (from 5, definitely superior contrast of lesions on DIR subtraction compared to conventional CE-T1W imaging, to 1, definitely superior contrast of lesions on CE-T1W imaging. The interrater agreement (κ coefficient) was measured. The signal-to-noise ratio (SNR) and contrast-noise-ratio (CNR) of the lesion were compared.

RESULTS

A significant difference (P < 0.001) in scoring was seen between conventional CE-T1W imaging (2.1 ± 1.5 with one reviewer and 2.4 ± 1.5 with the other) and DIR subtraction (4.4 ± 1.0 with one reviewer and 4.7 ± 0.8 with the other). SNR from conventional CE-T1W imaging (24.8 ± 14.7) was significantly superior to that from DIR subtraction (4.0 ± 1.0; P < 0.001). CNR in DIR subtraction (326.4 ± 250.0) was significantly superior to that in conventional CE-T1W imaging (0.8 ± 5.5; P < 0.001). For interrater agreement in the evaluation of contrast enhancement of the lesions, κ coefficients were 0.84 for conventional CE-T1W imaging and 0.72 for DIR subtraction.

CONCLUSION

Subtracted DIR image enables more obvious contrast enhancement of the MS lesions compared with conventional CE-T1W imaging.

Acceleration of Double Inversion Recovery Sequences in Multiple Sclerosis With Compressed Sensing

OBJECTIVE

The aim of this study was to assess the performance of double inversion recovery (DIR) sequences accelerated by compressed sensing (CS) in a clinical setting.

MATERIALS AND METHODS

We included 106 patients with MS (62 female [58%]; mean age, 44.9 ± 11.0 years) in this prospective study. In addition to a full magnetic resonance imaging protocol including a conventional SENSE accelerated DIR, we acquired a CS DIR (time reduction, 51%). We generated subtraction maps between the two DIR sequences to visualize focal intensity differences. Two neuroradiologists independently assessed these maps for intensity differences, which were categorized into definite MS lesions, possible lesions, or definite artifacts. Counts of focal intensity differences were compared using a Wilcoxon rank sum test. Moreover, conventional lesion counts were acquired for both sequences in independent readouts, and agreement between the DIR variants was assessed with intraclass correlation coefficients.

RESULTS

No hyperintensity that was rated as definite lesion was missed in the CS DIR. Two possible lesions were only detected in the conventional DIR, one only in the CS DIR (no significant difference, P = 0.57). The conventional DIR showed significantly more definite artifacts within the white matter (P = 0.024) and highly significantly more at the cortical-sulcal interface (P < 0.001). For both readers, intraclass correlation coefficient between the lesion counts in the two DIR variants was near perfect (0.985 for reader 1 and 0.981 for reader 2).

CONCLUSIONS

Compressed sensing can be used to substantially reduce scan time of DIR sequences without compromising diagnostic quality. Moreover, the CS accelerated DIR proved to be significantly less prone to imaging artifacts.

Improving acute demyelinating lesion detection: which T1-weighted magnetic resonance acquisition is more sensitive to gadolinium enhancement?

OBJECTIVE

Because of the need for a standardized and accurate method for detecting multiple sclerosis (MS) inflammatory activity, different magnetic resonance (MR) acquisitions should be compared in order to choose the most sensitive sequence for clinical routine. To compare the sensitivity of a T1-weighted image to a single dose of gadolinium (Gd) administration both with and without magnetization transfer to detect contrast enhancement in active demyelinating focal lesions.

METHODS

A sample of relapsing-remitting MS patients were prospectively examined separately by two neuroradiologists using a 1.5 Tesla scanner. The outcome parameters were focused on Gd-enhancement detection attributed to acute demyelination. All MR examinations with at least one Gd-enhancing lesion were considered positive (MR+) and each lesion was analyzed according to its size and contrast ratio.

RESULTS

Thirty-six MR examinations were analyzed with a high inter-observer agreement for MR+ detection (k coefficient > 0.8), which was excellent for the number of Gd-enhancing lesions (0.91 T1 spin-echo (SE), 0.88 T1 magnetization transfer contrast (MTC) sequence and 0.99 magnetization-prepared rapid acquisition with gradient-echo (MPRAGE). Significantly more MR+ were reported on the T1 MTC scans, followed by the T1 SE, and MPRAGE scans. Confidently, the T1 MTC sequence demonstrated higher accuracy in the detection of Gd-enhancing lesions, followed by the T1 SE and MPRAGE sequences. Further comparisons showed that there was a statistically significant increase in the contrast ratio and area of Gd-enhancement on the T1 MTC images when compared with both the SE and MPRAGE images.

CONCLUSION

Single-dose Gd T1 MTC sequence was confirmed to be the most sensitive acquisition for predicting inflammatory active lesions using a 1.5 T magnet in this sample of MS patients.

Gadolinium-Enhanced Susceptibility-Weighted Imaging in Multiple Sclerosis: Optimizing the Recognition of Active Plaques for Different MR Imaging Sequences

BACKGROUND AND PURPOSE

Gadolinium SWI is MR imaging that has recently been reported to be effective in the evaluation of several neurologic disorders, including demyelinating diseases. Our aim was to analyze the accuracy of gadolinium SWI for detecting the imaging evidence of active inflammation on MS plaques when a BBB dysfunction is demonstrated by a focal gadolinium-enhanced lesion and to compare this technique with gadolinium-enhanced T1 spin-echo and T1 spin-echo with magnetization transfer contrast.

MATERIALS AND METHODS

MR imaging studies of 103 patients (170 examinations) were performed using a 1.5T scanner. Two neuroradiologists scrutinized signal abnormalities of the demyelinating plaques on gadolinium SWI and compared them with gadolinium T1 before and after an additional magnetization transfer pulse. Interrater agreement was evaluated among gadolinium T1 magnetization transfer contrast, gadolinium SWI, and gadolinium T1 spin-echo using the κ coefficient. The T1 magnetization transfer contrast sequence was adopted as the criterion standard in this cohort. Thus, the sensitivity, specificity, positive predictive value, and negative predictive value were calculated for gadolinium T1 spin-echo and gadolinium SWI sequences.

RESULTS

Differences in BBB dysfunction were evident among gadolinium SWI, gadolinium T1 spin-echo, and gadolinium T1 magnetization transfer contrast. Gadolinium T1 magnetization transfer contrast demonstrated the highest number of active demyelinating plaques. Gadolinium SWI was highly correlated with gadolinium T1 magnetization transfer contrast in depicting acute demyelinating plaques (κ coefficient = 0.860; sensitivity = 0.837), and these techniques provided better performance compared with gadolinium T1 spin-echo (κ coefficient = 0.78; sensitivity = 0.645).

CONCLUSIONS

Gadolinium SWI was able to better detect BBB dysfunction in MS plaques and had a better performance than gadolinium T1 spin-echo. Increasing SWI sequence applications in clinical practice can improve our knowledge of MS, likely allowing the addition of BBB dysfunction analysis to the striking findings of the previously reported central vein sign.

3D double inversion recovery MR imaging: Clinical applications and usefulness in a wide spectrum of central nervous system diseases

Double inversion recovery (DIR) imaging provides two inversion pulses that attenuate signals from cerebrospinal fluid and normal white matter. This review was undertaken to describe the principle of the DIR sequence, the clinical applications of 3D DIR in various central nervous system diseases and the clinical benefits of the 3D DIR compared with those of other MR sequences. 3D DIR imaging provides better lesion conspicuity and topography than other MR techniques. It is particularly useful for diagnosing the following disease entities: cortical and subcortical abnormalities such as multiple sclerosis, cortical microinfarcts and cortical development anomalies; sulcal abnormalities such as meningitis and subacute/chronic subarachnoid hemorrhage; and optic neuritis caused by multiple sclerosis or neuromyelitis optica.