Sensitivity of Immediate and Delayed Gadolinium-Enhanced MRI After Injection of 0.5 M and 1.0 M Gadolinium Chelates for Detecting Multiple Sclerosis Lesions

Investigating the feasibility of differentiating MS active lesions from inactive ones using texture analysis and machine learning methods in DWI images

BACKGROUND

Magnetic resonance imaging (MRI) is commonly used in conjunction with a gadolinium-based contrast agent (GBCA) to distinguish active multiple sclerosis (MS) lesions. However, recent studies have raised concerns regarding the long-term effects of the accumulation of GBCA in the body. Thus, the purpose of this study is to investigate the possibility of using texture analysis in diffusion-weighted imaging (DWI) and machine learning algorithms to discriminate active from inactive MS lesions without the use of GBCA.

METHODS

To achieve this purpose, we introduce an image processing pipeline. In the proposed pipeline, following registration and alignment of slices, MS lesions from DWI images are segmented and quantized. Next, different texture analysis methods are employed to extract texture features from the lesions. Then, a two-stage feature reduction method is applied, in which the first stage involves a statistical t-test and the second stage relies on principal component analysis (PCA), sequential forward selection (SFS), sequential backward selection (SBS), and ReliefF algorithms. Finally, we use five classifiers logistic regression (LR), support vector machine (SVM), decision tree (DT), K nearest neighbor (KNN), and linear discriminant analysis (LDA) in a 5-fold cross-validation procedure to determine active and inactive MS lesions.

RESULTS

In this study, we collected and prepared 255 active/inactive MS lesions from MRI scans of 34 patients diagnosed with MS, with a mean age of 35.56±10.89. Among 89 texture features extracted, 63 features showed statistically significant differences between the means of active and inactive lesions (P<0.05). The SVM classifier with the PCA feature reduction algorithm demonstrated the best performance with an average accuracy of 0.960 (±0.024), specificity and precision of 1.0, sensitivity of 0.913 (±0.053), and AUC of 0.957 (±0.027).

CONCLUSION

Our study indicates that DWI changes detected using texture analysis-based machine learning models can precisely differentiate active from inactive MS lesions. This finding provides valuable clinical information for the early diagnosis and effective monitoring of MS disease.

Investigating the Ability of Radiomics Features for Diagnosis of the Active Plaque of Multiple Sclerosis Patients

Background

Multiple sclerosis (MS) is the most common non-traumatic disabling disease.

Objective

The aim of this study is to investigate the ability of radiomics features for diagnosing active plaques in patients with MS from T2 Fluid Attenuated Inversion Recovery (FLAIR) images.

Material and Methods

In this experimental study, images of 82 patients with 122 MS lesions were investigated. Boruta and Relief algorithms were used for feature selection on the train data set (70%). Four different classifier algorithms, including Multi-Layer Perceptron (MLP), Gradient Boosting (GB), Decision Tree (DT), and Extreme Gradient Boosting (XGB) were used as classifiers for modeling. Finally, Performance metrics were obtained on the test data set (30%) with 1000 bootstrap and 95% confidence intervals (95% CIs).

Results

A total of 107 radiomics features were extracted for each lesion, of which 7 and 8 features were selected by the Relief method and Boruta method, respectively. DT classifier had the best performance in the two feature selection algorithms. The best performance on the test data set was related to Boruta-DT with an average accuracy of 0.86, sensitivity of 1.00, specificity of 0.84, and Area Under the Curve (AUC) of 0.92 (95% CI: 0.92-0.92).

Conclusion

Radiomics features have the potential for diagnosing MS active plaque by T2 FLAIR image features. Additionally, choosing the feature selection and classifier algorithms plays an important role in the diagnosis of active plaque in MS patients. The radiomics-based predictive models predict active lesions accurately and non-invasively.

Diffusion-Weighted Images and Contrast-Enhanced MRI in the Diagnosis of Different Stages of Multiple Sclerosis of the Central Nervous System

Introduction Multiple sclerosis (MS) is one of the most prevalent disorders of the central nervous system (CNS), and it can be observed in the field of radiological cross-sectional magnetic resonance imaging (MRI). The prevalence of MS in Saudi Arabia has increased as compared to the past few years. MRI is the gold standard non-invasive modality of choice in MS diagnosis according to the National Multiple Sclerosis Society (NMSS), New York City. This study aimed to highlight the significance of using diffusion-weighted images (DWIs) and the use of contrast media in the MS protocol, as well as the importance of identifying the suitable time of imaging after contrast enhancement to detect active lesions. Methods A retrospective cross-sectional study was conducted of 100 MS patients with an age range of 17 to 56 years. The data set included 41 active cases and 59 inactive cases. All patients had an MRI standard protocol of both the brain and spine in addition to DWI sequence and contrast agent (CA) injection, with images taken in early and delayed time. Results Of the patients, 71% were female and 29% were male. Active MS disease was more significant at younger ages than at older ages. Active lesions were significantly enhanced in delayed contrast images and showed high signal intensity in both the DWI and apparent diffusion coefficient (ADC) map, while inactive lesions showed no enhancement after contrast injection and showed an iso-signal intensity in both the DWI and ADC map. Conclusion The use of CA has developed over the years in the diagnosis of MS patients. In this study, the relationship between active lesions, DWI, and delayed contrast enhancement is very strong. In future research, we recommend adding a DWI sequence for the suspected active MS spine lesions in addition to delayed enhancement time in active MS after contrast injection to increase MRI sensitivity toward active MS lesions of the brain and spinal cord as well.

Contrast enhancement in cerebral adrenoleukodystrophy: a comparison of T1 TSE and MPRAGE sequences

PURPOSE

To compare conventional T1 TSE with MPRAGE for enhancement detection in cerebral adrenoleukodystrophy (CALD).

MATERIALS AND METHODS

Contrast-enhanced T1 TSE and MPRAGE sequences of 34 CALD patients demonstrating enhancement were evaluated. Contrast ratios were calculated by drawing ROIs to the most enhancing part of demyelination and normal-appearing deep white matter on both T1 TSE and MPRAGE. A comparison was performed between ratios using paired T test.

RESULTS

Mean age of 34 included male children was 8 (5-11 years). There was no statistically significant difference between T1 TSE and MPRAGE ratios. However, in 4 out of 34 examinations, minimal contrast enhancement was noted only in T1 TSE sequence.

CONCLUSION

Our data indicate that both T1 TSE and MPRAGE sequences are valuable in determining contrast enhancement in CALD. Although there is not a statistically significant difference between the two techniques, T1 TSE sequence appears to be more sensitive for low degree of enhancement.

Imaging in X-Linked Adrenoleukodystrophy

Magnetic resonance imaging (MRI) is the gold standard for the detection of cerebral lesions in X-linked adrenoleukodystrophy (ALD). ALD is one of the most common peroxisomal disorders and is characterized by a defect in degradation of very long chain fatty acids (VLCFA), resulting in accumulation of VLCFA in plasma and tissues. The clinical spectrum of ALD is wide and includes adrenocortical insufficiency, a slowly progressive myelopathy in adulthood, and cerebral demyelination in a subset of male patients. Cerebral demyelination (cerebral ALD) can be treated with hematopoietic cell transplantation (HCT) but only in an early (pre- or early symptomatic) stage and therefore active MRI surveillance is recommended for male patients, both pediatric and adult. Although structural MRI of the brain can detect the presence and extent of cerebral lesions, it does not predict if and when cerebral demyelination will occur. There is a great need for imaging techniques that predict onset of cerebral ALD before lesions appear. Also, imaging markers for severity of myelopathy as surrogate outcome measure in clinical trials would facilitate drug development. New quantitative MRI techniques are promising in that respect. This review focuses on structural and quantitative imaging techniques-including magnetic resonance spectroscopy, diffusion tensor imaging, MR perfusion imaging, magnetization transfer (MT) imaging, neurite orientation dispersion and density imaging (NODDI), and myelin water fraction imaging-used in ALD and their role in clinical practice and research opportunities for the future.

Pre-contrast T1-weighted imaging of the spinal cord may be unnecessary in patients with multiple sclerosis

Objectives

Multiple sclerosis (MS) is an inflammatory disease frequently involving the spinal cord, which can be assessed by magnetic resonance imaging (MRI). Here, we hypothesize that pre-contrast T1-w imaging does not add diagnostic value to routine spinal MRI for the follow-up of patients with MS.

Methods

3-T MRI scans including pre- and post-contrast T1-w as well as T2-w images of 265 consecutive patients (mean age: 40 ± 13 years, 169 women) with (suspected) MS were analyzed retrospectively. Images were assessed in two separate reading sessions, first excluding and second including pre-contrast T1-w images. Two independent neuroradiologists rated the number of contrast-enhancing (ce) lesions as well as diagnostic confidence (1 = unlikely to 5 = very high), overall image quality, and artifacts. Results were compared using Wilcoxon matched-pairs signed-rank tests and weighted Cohen’s kappa (κ).

Results

Fifty-six ce lesions were found in 43 patients. There were no significant differences in diagnostic confidence between both readings for both readers (reader 1: p = 0.058; reader 2: p = 0.317). Inter-rater concordance was both moderate regarding artifacts (κ = 0.418) and overall image quality (κ = 0.504). Thirty-one black holes were found in 25 patients with high diagnostic confidence (reader 1: 4.04 ± 0.81; reader 2: 3.80 ± 0.92) and substantial inter-rater concordance (κ = 0.700).

Conclusions

Availability of pre-contrast T1-w images did not significantly increase diagnostic confidence or detection rate of ce lesions in the spinal cord in patients with MS. Thus, pre-contrast T1-w sequences might be omitted in routine spinal MRI for follow-up exams, however not in special unclear clinical situations in which certainty on contrast enhancement is required.

Key Points

Availability of pre-contrast T1-w images does not increase diagnostic confidence or detection rate of contrast-enhancing lesions in the spinal cord of MS patients.

Excluding pre-contrast T1-w sequences reduces scan time, thus providing more time for other sequences or increasing the patients’ compliance.

Improved Lesion Conspicuity with Contrast-Enhanced 3D T1 TSE Black-Blood Imaging in Cranial Neuritis: A Comparative Study of Contrast-Enhanced 3D T1 TSE, 3D T1 Fast-Spoiled Gradient Echo, and 3D T2 FLAIR

BACKGROUND AND PURPOSE

Contrast-enhanced 3D-turbo spin-echo (TSE) black-blood sequence has gained attention, as it suppresses signals from vessels and provides an increased contrast-noise ratio. The purpose was to investigate which among the contrast-enhanced 3D T1 TSE, 3D T1 fast-spoiled gradient echo (FSPGR), and 3D T2 FLAIR sequences can better detect cranial nerve contrast enhancement.

MATERIALS AND METHODS

Patients with cranial neuritis based on clinical findings (n = 20) and control participants (n = 20) were retrospectively included in this study. All patients underwent 3T MR imaging with contrast-enhanced 3D T1 TSE, 3D T1 FSPGR, and 3D T2 FLAIR. Experienced and inexperienced reviewers independently evaluated the 3 sequences to compare their diagnostic performance and time required to reach the diagnosis. Additionally, tube phantoms containing varying concentrations of gadobutrol solution were scanned using the 3 sequences.

RESULTS

For the inexperienced reader, the 3D T1 TSE sequence showed significantly higher sensitivity (80% versus 50%, P = .049; 80% versus 55%; P = .040), specificity (100% versus 65%, P = .004; 100% versus 60%; P = .001), and accuracy (90% versus 57.5%, P = .001; 90% versus 57.5%, P = .001) than the 3D T1 FSPGR and 3D T2 FLAIR sequences in patients with cranial neuritis. For the experienced reader, the 3D T1-based sequences showed significantly higher sensitivity than the 3D T2 FLAIR sequence (85% versus 30%, P < .001; 3D T1 TSE versus 3D T2 FLAIR, 85% versus 30%, P < .001; 3D T1 FSPGR versus 3D T2 FLAIR). For both readers, the 3D T1 TSE sequence showed the highest area under the curve (inexperienced reader; 0.91, experienced reader; 0.87), and time to diagnosis was significantly shorter with 3D T1 TSE than with 3D T1 FSPGR.

CONCLUSIONS

The 3D T1 TSE sequence may be clinically useful in evaluating abnormal cranial nerve enhancement, especially for inexperienced readers.

Delayed phases of contrast MRI, can it be valuable in multiple sclerosis active phase diagnosis?

Background:

Observing the enhancing plaques in magnetic resonance imaging (MRI) is one of the most valuable diagnostic modalities in confirming the diagnosis of multiple sclerosis (MS), its recurrence and for better detection of active disease. Since active lesions discovery can improve designating diffusion in time diagnosis of MS and controlling disease activity, and there is not any definite time for delay image acquisition, therefore, the aim of the current study was to evaluate the enhancement of MS plaques in different delayed phases.

Methods:

In this interventional study, after receiving written consent, 40 MS patients with at least one enhancing plaque in a previous MRI were evaluated in Babol Ayatollah Rouhani Hospital. Gadolinium was injected to all patients at the dose of 0.1 mg/kg, and MRI was taken at 5 and 15 minutes. The results were analyzed using SPSS 23. A p<0.05 was considered as significant level.

Results:

The mean of plaque signal intensity was 1190.20 and 1349.60 at 5 and 15 min, respectively, and this difference was significant (p<0.001). Moreover, the mean of plaque total size was 5.16 cm and 7.04 cm at 5 and 15 min with significant difference, respectively (p<0.001). The mean of plaque number was 1.92 and 2.58 at 5 and 15 min, respectively, which was significantly different (P<0.001).

Conclusion:

The results indicated improvement in detection of MS plaques in images taken in the delayed phase compared to those in the early phase. The plaque intensity, size and number were significantly higher in the delayed phase (15 min), than early phase (5 min).

Gadolinium-Enhanced 3D T1-Weighted Black-Blood MR Imaging for the Detection of Acute Optic Neuritis

BACKGROUND AND PURPOSE

A 3D T1-weighted black-blood sequence was recently shown to improve the detection of contrast-enhancing lesions in the brain in patients with MS compared with a 3D T1-weighted MPRAGE sequence. We compared a contrast-enhanced 3D T1-weighted black-blood sequence with a dedicated orbital contrast-enhanced T1-weighted Dixon sequence in patients with acute optic neuritis.

MATERIALS AND METHODS

MR imaging data (3T) of 51 patients showing symptoms of acute optic neuritis were analyzed retrospectively, including whole-brain contrast-enhanced 3D T1-weighted black-blood and dedicated orbital coronal 2D or 3D contrast-enhanced T1-weighted Dixon sequences. Two neuroradiologists assessed the images for overall image quality, artifacts, diagnostic confidence, and visual contrast enhancement. Furthermore, the standardized contrast-to-noise ratio was calculated. The final diagnosis of acute optic neuritis was established on the basis of clinical presentation, visually evoked potentials, and optical coherence tomography.

RESULTS

Thirty of 51 patients were diagnosed with acute optic neuritis. Of those, 21 showed contrast-enhancing lesions in the optic nerves, similarly detectable on contrast-enhanced T1-weighted Dixon and contrast-enhanced T1-weighted black-blood images. Thus, the accuracy for each sequence was identical, with a resulting sensitivity of 70% and specificity of 90% or 100% (depending on the reader). Overall image quality, diagnostic confidence, visual contrast enhancement, and artifacts were rated similarly in contrast-enhanced 3D T1-weighted black-blood and dedicated orbital contrast-enhanced T1-weighted Dixon sequences. There was no significant difference (P = .27) in the mean standardized contrast-to-noise ratio between contrast-enhanced T1-weighted black-blood (1.76 ± 1.07) and contrast-enhanced T1-weighted Dixon (2.29 ± 2.49) sequences.

CONCLUSIONS

Contrast-enhanced 3D T1-weighted black-blood imaging is comparable in accuracy and qualitative/quantitative features with dedicated orbital contrast-enhanced T1-weighted Dixon imaging for the detection of acute optic neuritis. Therefore, when used, it has the potential to considerably shorten total patient imaging time.

Imaging in Pediatric Multiple Sclerosis : An Iconographic Review

Pediatric-onset multiple sclerosis (POMS) is defined by a first multiple sclerosis (MS) attack occurring before 18 years old and is diagnosed by demonstration of dissemination in time (DIT) and space (DIS). Although guidelines evolved over the years, they always recognized the importance of magnetic resonance imaging (MRI) for diagnosis. The 2017 McDonald criteria are increasingly used and have been validated in several cohorts. The use of MRI is the most important tool for the early diagnosis, monitoring, and assessment of treatment response of MS and standard protocols include precontrast and postcontrast T1, T2, fluid attenuation inversion recovery (FLAIR) and diffusion sequences. A distinctive MS lesion compromises white matter and it is well-demarcated and confluent, showing demyelination, inflammation, gliosis, and relative axonal preservation. Considering the growing recognition of pediatric MS as a differential diagnosis for children presenting with a clinical central nervous system event, we present a POMS lesions guide (periventricular, juxtacortical, infratentorial, spinal cord, cortical, tumefactive, black hole, contrast-enhanced). Owing to its rareness, POMS is a diagnosis by exclusion and MRI plays a fundamental role in distinguishing POMS from other demyelinating and non-demyelinating conditions. Three main groups of disorders can mimic POMS: inflammatory, metabolic and tumoral; however, imaging patterns earlier described lower the possibilities of alternative diagnoses and strongly suggest POMS when likely.

Contrast-enhanced modified 3D T1-weighted TSE black-blood imaging can improve detection of infectious and neoplastic meningitis

OBJECTIVES

To evaluate the diagnostic value of a contrast-enhanced 3D T1-weighted-modified volumetric isotropic turbo spin-echo acquisition sequence (T1-mVISTA) in comparison with a conventional 3D T1-weighted magnetization-prepared rapid gradient-echo (T1-MP-RAGE) sequence for the detection of meningeal enhancement in patients with meningitis.

METHODS

Thirty patients (infectious meningitis, n = 12; neoplastic meningitis, n = 18) and 45 matched controls were enrolled in this retrospective case-control study. Sets of randomly selected T1-mVISTA and T1-MP-RAGE images (both with 0.8-mm isotropic resolution) were read separately 4 weeks apart. Image quality, leptomeningeal and dural enhancement, grading of visual contrast enhancement, and diagnostic confidence were compared using the Kruskal-Wallis rank sum test.

RESULTS

Image quality was rated to be good to excellent in 75 out of 75 cases (100%) for T1-mVISTA and 74 out of 75 cases (98.7%) for T1-MP-RAGE. T1-mVISTA detected significantly more patients with leptomeningeal enhancement (p = 0.006) compared with T1-MP-RAGE (86.7 vs. 50.0%, p < 0.001), each with specificity of 100%. Similarly, sensitivity of T1-mVISTA for the detection of dural and/or leptomeningeal enhancement was also significantly higher compared with that of T1-MP-RAGE (96.7 vs. 80.0%, p = 0.025) without significant differences regarding specificity (97.8 vs. 95.6%, p = 0.317). No significant differences were found for dural enhancement alone. Diagnostic confidence in T1-mVISTA was significantly higher (p = 0.01). Visual contrast enhancement was tendentially higher in T1-mVISTA.

CONCLUSIONS

T1-mVISTA may be an adequate and probably better alternative to T1-MP-RAGE for detection of leptomeningeal diseases.

KEY POINTS

• Black-blood T1-mVISTA showed a significant higher sensitivity for the detection of leptomeningeal enhancement compared with MP-RAGE without losses regarding specificity. • Diagnostic confidence was assessed significantly higher in T1-mVISTA. • T1-mVISTA should be considered a supplement or an alternative to T1-MP-RAGE in patients with suspected leptomeningeal diseases.

Application of Synthetic MRI for Direct Measurement of Magnetic Resonance Relaxation Time and Tumor Volume at Multiple Time Points after Contrast Administration: Preliminary Results in Patients with Brain Metastasis

Objective

The purpose of this study was to investigate the time-dependent effects of contrast medium on multi-dynamic, multi-echo (MDME) sequence in patients with brain metastases.

Materials and Methods

This study included 7 patients with 15 brain metastases who underwent magnetic resonance (MR) examination which included MDME sequences at 1 minute, 10 minutes and 20 minutes after contrast injection. Two volumes of interests, covering an entire tumor (whole tumor) and the enhancing portion of the tumor, were derived from post-contrast synthetic T1-weighted images. Statistical comparisons were performed for three different time delays for histogram parameters of the longitudinal relaxation rate (R₁) and the transverse relaxation rate (R₂), and lesion volumes.

Results

The mean and the median of R₁ and the mean of R₂ in both the whole tumor and the inner enhancing portion were larger on the 10 minutes delayed images than on the 1 minute or 20 minutes delayed images (mean of R₁ in the whole tumor on the 1 minute, 10 minutes, and 20 minutes delayed images: 1.26 ms, 1.39 ms, and 1.37 ms; mean of R₁ in the inner enhancing portion: 1.43 ms, 1.53 ms and 1.44 ms; all p < 0.017). The volumes of the whole tumor and the inner enhancing portion were significantly larger in the 10 minutes and 20 minutes delayed images than on the 1 minute delayed images (all p < 0.017).

Conclusion

Magnetic resonance relaxation times and the volumes of the whole tumor and the inner enhancing portion were measured larger on the 10 minutes or 20 minutes delayed images than on the 1 minute delayed images. The MDME sequence immediately after contrast injection cannot fully reflect the effects of gadolinium-based contrast agent leakage in the tissue.

Multiple Sclerosis: Improved Detection of Active Cerebral Lesions With 3-Dimensional T1 Black-Blood Magnetic Resonance Imaging Compared With Conventional 3-Dimensional T1 GRE Imaging

OBJECTIVES

The aim of this study was to assess the diagnostic accuracy of a modified high-resolution whole-brain three-dimensional T1-weighted black-blood sequence (T1-weighted modified volumetric isotropic turbo spin echo acquisition [T1-mVISTA]) in comparison to a standard three-dimensional T1-weighted magnetization-prepared rapid gradient echo (MP-RAGE) sequence for detection of contrast-enhancing cerebral lesions in patients with relapsing-remitting multiple sclerosis (MS).

MATERIALS AND METHODS

After institutional review board approval and informed consent, 22 patients (8 men; aged 31.0 ± 9.2 years) with relapsing-remitting MS were included in this monocentric prospective cohort study.Contrast-enhanced T1-mVISTA and MP-RAGE, both with 0.8 mm resolution, were performed in all patients. In a substudy of 12 patients, T1-mVISTA was compared with a T1-mVISTA with 1.0 mm resolution (T1-mVISTA_1.0). Reference lesions were defined by an experienced neuroradiologist using all available sequences and served as the criterion standard. T1-mVISTA, T1-mVISTA_1.0, and MP-RAGE sequences were read in random order 4 weeks apart. Image quality, visual contrast enhancement, contrast-to-noise-ratio (CNR), diagnostic confidence, and lesion size were assessed and compared by Wilcoxon and Mann-Whitney U tests.

RESULTS

Eleven of 22 patients displayed contrast-enhancing lesions. Visual contrast enhancement, CNR, and diagnostic confidence of contrast-enhancing MS lesions were significantly increased in T1-mVISTA compared with MP-RAGE (P < 0.001). Significantly more contrast-enhancing lesions were detected with T1-mVISTA than with MP-RAGE (71 vs 39, respectively; P < 0.001). With MP-RAGE, 25.6% of lesions were missed in the initial reading, whereas only 4.2% of lesions were missed with T1-mVISTA. Increase of the voxel volume from 0.8 mm to 1.0 mm isotropic in T1-mVISTA_1.0 did not affect the detectability of lesions, whereas scan time was decreased from 4:43 to 1:55 minutes.

CONCLUSIONS

Three-dimensional T1-mVISTA improves the detection rates of contrast-enhancing cerebral MS lesions compared with conventional 3D MP-RAGE sequences by increasing CNR of lesions and might, therefore, be useful in patient management.

Proton Density Fat Suppressed MRI in 3T Increases the Sensitivity of Multiple Sclerosis Lesion Detection in the Cervical Spinal Cord

PURPOSE

Considering the number of multiple sclerosis (MS) patients referred for clinical spinal cord imaging, the optimization of imaging protocols plays a crucial role. We aimed to evaluate the use of proton density (PD) turbo spin-echo (TSE) with spectral attenuated inversion recovery (SPAIR) fat suppression and compare it with the currently recommended T2-TSE-SPAIR in sagittal plane in cervical spinal cord imaging.

METHODS

In this study 35 MS patients with clinically suspected or known spinal cord lesions were scanned on a 3.0T magnetic resonance imaging (MRI) system. In addition to the routine protocol, PD-TSE-SPAIR sequences were obtained to quantitatively and qualitatively evaluate lesion detectability and image quality compared to T2-TSE-SPAIR sequences. Quantitative analysis was based on measurements of lesion-to-cord contrast ratio (LCCR), lesion contrast-to-noise ratio (LCNR) and lesion dimensions and the qualitative analysis on ranking with a predetermined score scale. The presence of lesions in these sequences was verified in axial T2 multi-echo gradient echo images.

RESULTS

In quantitative analysis, the lesions on PD-TSE-SPAIR had statistically significantly higher contrast (p < 0.05), according to the statistical test of LCCR, LCNR calculated contrast and measured lesion dimensions. Qualitative analyses were congruent with quantitative results; the median rank of PD-TSE-SPAIR was significantly higher than T2-TSE-SPAIR (p < 0.05). Of the 34 detected lesions 9 (26%) were not visualized in T2-TSE-SPAIR sequence.

CONCLUSION

Considering its superiority in contrast ratios and lesion dimensions when compared to T2-TSE-SPAIR in both qualitative and quantitative analyses, we therefore recommend PD-TSE-SPAIR as a pivotal sequence to evaluate demyelinating spinal cord lesions at 3T.

Serum netrin-1 in relation to gadolinium-enhanced magnetic resonance imaging in early multiple sclerosis

Background

Netrin-1, a secreted laminin-related protein, is known to regulate not only axonal guidance and neuronal cell migration, but also blood–brain barrier integrity and inflammation. Two preliminary studies reported altered serum netrin-1 levels in multiple sclerosis; however, associations with longitudinal clinical and magnetic resonance imaging activity have not been investigated.

Objectives

We aimed to assess serum netrin-1 in multiple sclerosis and controls with respect to disease activity and its temporal dynamics.

Methods

Serum netrin-1 was assessed by enzyme-linked immunosorbent assay in 79 patients with clinically isolated syndrome or multiple sclerosis, and 30 non-inflammatory neurological disease controls. In patients, serum samples were collected immediately prior to gadolinium-enhanced 3 T magnetic resonance imaging at two time points (initial contrast-enhancing gadolinium+ n = 47, non-enhancing gadolinium– n = 32; reference gadolinium– n = 70; median time-lag 1.4, interquartile range 1.0–2.3 years).

Results

Serum netrin-1 levels were similar in clinically isolated syndrome, multiple sclerosis and controls, and gadolinium+ and gadolinium– patients. Among gadolinium+ patients, serum netrin-1 was decreased in clinically active (n = 8) vs non-active patients (n = 39; p = 0.041). Serum netrin-1 showed no temporal dynamics in multiple sclerosis and was unrelated to clinical data.

Conclusions

Serum netrin-1 levels show no multiple sclerosis specific changes and are not sensitive for detection of subclinical disease activity. Netrin-1 changes during relapses may deserve further examination.

T1w dark blood imaging improves detection of contrast enhancing lesions in multiple sclerosis

PURPOSE

In multiple sclerosis (MS) the sensitivity for detection of contrast enhancing lesions (CEL) in T1-weighted scans is essential for diagnostics and therapy decisions. The purpose of our study was to evaluate the sensitivity of T1w MPRAGE scans in comparison to T1w dark blood technique (T1-DB) for CEL in MS.

MATERIALS AND METHODS

3T MR imaging was performed in 37 MS patients, including T2-weighted imaging, T1w MPRAGE before and after gadolinium injection (unenhanced-T1 and T1-CE) and T1-DB imaging. After gadolinium application, the T1-DB scan was performed prior to T1-CE. From unenhanced-T1 and T1-CE scans, subtraction images (T1-SUB) were calculated. The number of CEL was determined separately on T1-CE and T1-DB by two raters independently. Lesions only detected on T1-DB scans then were verified on T1-SUB. Only lesions detected by both raters were included in further analysis.

RESULTS

In 16 patients, at least one CEL was detected by both rater, either on T1-CE or T1-DB. All lesions that were detected on T1-CE were also detected on T1-DB images. The total number of contrast enhancing lesions detected on T1-DB images (n = 54) by both raters was significantly higher than the corresponding number of lesions identified on T1-CE (n = 27) (p = 0.01); all of these lesions could be verified on SUB images. In 21 patients, no CEL was detected in any of the sequences.

CONCLUSIONS

The application of T1-DB technique increases the sensitivity for CEL in MS, especially for those lesions that show only subtle increase in intensity after Gadolinium application but remain hypo- or iso-intense to surrounding tissue.

Cumulative Dose of Macrocyclic Gadolinium-Based Contrast Agent Improves Detection of Enhancing Lesions in Patients with Multiple Sclerosis

BACKGROUND AND PURPOSE

Gadolinium-enhanced MR imaging is currently the reference standard for detecting active inflammatory lesions in patients with multiple sclerosis. The sensitivity of MR imaging for this purpose may vary according to the physicochemical characteristics of the contrast agent used and the acquisition strategy. The purpose of this study was to compare detection of gadolinium-enhancing lesions or active disease following a single or cumulative dose of a macrocyclic gadolinium-based contrast agent with different image acquisition delays in patients with clinically isolated syndrome or relapsing multiple sclerosis.

MATERIALS AND METHODS

All patients received a first dose (0.1 mmol/kg) of gadobutrol and, 20 minutes later, a second dose (0.1 mmol/kg), with a cumulative dose of 0.2 mmol/kg. Two contrast-enhanced T1-weighted sequences were performed at 5 and 15 minutes after the first contrast administration, and 2 additional T1-weighted sequences at 5 and 15 minutes after the second contrast administration with a 3T magnet.

RESULTS

One hundred fifteen patients were considered evaluable. A significantly larger number of lesions were detected in scans obtained at 5 and 15 minutes after the second contrast injection compared with scans obtained at 5 and 15 minutes after the first injection (P < .001). The number of patients with active lesions on MR imaging was significantly higher after the second dose administration (52.0%, first dose versus 59.2%, second dose; P < .001).

CONCLUSIONS

Cumulative dosing of a macrocyclic gadolinium-based contrast agent increases detection of enhancing lesions and patients with active lesions. These data could be considered in the design of MR imaging protocols aimed at detecting active multiple sclerosis lesions.

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

BACKGROUND AND PURPOSE

The double inversion recovery sequence is known to be very sensitive and specific for MS-related lesions. Our aim was to compare the sensitivity of pre- and postcontrast images of 3D double inversion recovery and conventional 3D T1-weighted images for the detection of contrast-enhancing MS-related lesions in the brain to analyze whether double inversion recovery could be as effective as T1WI.

MATERIALS AND METHODS

A postcontrast 3D double inversion recovery sequence was acquired in addition to the standard MR imaging protocol at 3T, including pre- and postcontrast 3D T1WI sequences as well as precontrast double inversion recovery of 45 consecutive patients with MS or clinically isolated syndrome between June and December 2013. Two neuroradiologists independently assessed precontrast, postcontrast, and subtraction images of double inversion recovery as well as T1WI to count the number of contrast-enhancing lesions. Afterward, a consensus reading was performed. Lin concordance was calculated between both radiologists, and differences in lesion detectability were assessed with the Student t test. Additionally, the contrast-to-noise ratio was calculated.

RESULTS

Significantly more contrast-enhancing lesions could be detected with double inversion recovery compared with T1WI (16%, 214 versus 185, P = .007). The concordance between both radiologists was almost perfect (ρ_c = 0.94 for T1WI and ρ_c = 0.98 for double inversion recovery, respectively). The contrast-to-noise ratio was significantly higher in double inversion recovery subtraction images compared with T1-weighted subtraction images (double inversion recovery, 14.3 ± 5.5; T1WI, 6.3 ± 7.1; P < .001).

CONCLUSIONS

Pre- and postcontrast double inversion recovery enables better detection of contrast-enhancing lesions in MS in the brain compared with T1WI and may be considered an alternative to the standard MR imaging protocol.

MRI in the assessment and monitoring of multiple sclerosis: an update on best practice

Magnetic resonance imaging (MRI) has developed into the most important tool for the diagnosis and monitoring of multiple sclerosis (MS). Its high sensitivity for the evaluation of inflammatory and neurodegenerative processes in the brain and spinal cord has made it the most commonly used technique for the evaluation of patients with MS. Moreover, MRI has become a powerful tool for treatment monitoring, safety assessment as well as for the prognostication of disease progression. Clinically, the use of MRI has increased in the past couple decades as a result of improved technology and increased availability that now extends well beyond academic centers. Consequently, there are numerous studies supporting the role of MRI in the management of patients with MS. The aim of this review is to summarize the latest insights into the utility of MRI in MS.

Current and Emerging Therapies in Multiple Sclerosis: Implications for the Radiologist, Part 1-Mechanisms, Efficacy, and Safety

Imaging for the diagnosis and follow-up of patients with suspected or confirmed multiple sclerosis is a common scenario for many general radiologists and subspecialty neuroradiologists. The field of MS therapeutics has rapidly evolved with multiple new agents now being used in routine clinical practice. To provide an informed opinion in discussions concerning newer MS agents, radiologists must have a working understanding of the strengths and limitations of the various novel therapies. The role of imaging in MS has advanced beyond monitoring and surveillance of disease activity to include treatment complications. An understanding of the new generation of MS drugs in conjunction with the key role that MR imaging plays in the detection of disease progression, opportunistic infections, and drug-related adverse events is of vital importance to the radiologist and clinical physician alike. Radiologists are in a unique position to detect many of the described complications well in advance of clinical symptoms. Part 1 of this review outlines recent developments in the treatment of MS and discusses the published clinical data on the efficacy and safety of the currently approved and emerging therapies in this condition as they apply to the radiologist. Part 2 will cover pharmacovigilance and the role the neuroradiologist plays in monitoring patients for signs of opportunistic infection and/or disease progression.

Effects of gadolinium-based contrast agent concentrations (0.5 M or 1.0 M) on the diagnostic performance of magnetic resonance imaging examinations: systematic review of the literature

Background To date there is no agreement as to what is the optimal concentration for gadolinium-based contrast agents (GBCAs). Purpose To assess whether diagnostic performance differences exist between 0.5 M and 1.0 M GBCAs used for magnetic resonance imaging (MRI). Material and Methods A PubMed literature search identified 21 clinical studies published between 2005 and 2013 which evaluated the diagnostic efficacy of both types of GBCAs. Study design, type of procedure, GBCA administration mode, imaging performances, impact on patient management, study limitations, and biases were analyzed. No statistical test was performed on pooled data. Results Sixteen comparative and five non-comparative studies were analyzed, involving 2183 patients who underwent MRI procedures for various indications. In 67% of the studies, 0.5 M and 1.0 M GBCAs were injected at equimolar gadolinium amounts per kg body weight. Only 33% applied the same molar flow rate for delivery of the GBCAs. No significant differences between GBCAs were reported for 23 out of 27 qualitative endpoints (mainly image quality, lesion, and vessel visualization) and 29 out of 40 quantitative endpoints. Three out of four studies with non-equimolar delivery rates showed better contrast-to-noise and signal-to-noise ratios for 1.0 M gadobutrol, without showing an impact on diagnostic performance. Methodological biases were identified in several studies impairing the interpretation of comparisons. Conclusion Imaging differences between 0.5 M and 1.0 M GBCAs were essentially observed under non-equimolar delivery rates. However, they did not result into greater diagnostic efficacy when performed under equimolar conditions.

Time-delayed contrast-enhanced MRI improves detection of brain metastases: a prospective validation of diagnostic yield

The radiological detection of brain metastases (BMs) is essential for optimizing a patient's treatment. This statement is even more valid when stereotactic radiosurgery, a noninvasive image guided treatment that can target BM as small as 1-2 mm, is delivered as part of that care. The timing of image acquisition after contrast administration can influence the diagnostic sensitivity of contrast enhanced magnetic resonance imaging (MRI) for BM. Investigate the effect of time delayed acquisition after administration of intravenous Gadavist® (Gadobutrol 1 mmol/ml) on the detection of BM. This is a prospective IRB approved study of 50 patients with BM who underwent post-contrast MRI sequences after injection of 0.1 mmol/kg Gadavist® as part of clinical care (time-t0), followed by axial T1 sequences after a 10 min (time-t1) and 20 min delay (time-t2). MRI studies were blindly compared by three neuroradiologists. Single measure intraclass correlation coefficients were very high (0.914, 0.904 and 0.905 for time-t0, time-t1 and time-t2 respectively), corresponding to a reliable inter-observer correlation. The delayed MRI at time-t2 delayed sequences showed a significant and consistently higher diagnostic sensitivity for BM by every participating neuroradiologist and for the entire cohort (p = 0.016, 0.035 and 0.034 respectively). A disproportionately high representation of BM detected on the delayed studies was located within posterior circulation territories (compared to predictions based on tissue volume and blood-flow volumes). Considering the safe and potentially high yield nature of delayed MRI sequences, it should supplement the standard MRI sequences in all patients in need of precise delineation of their intracranial disease.

Altered signal intensity of active enhancing inflammatory lesions using post-contrast double inversion recovery MR sequence

OBJECTIVES

We aimed at establishing the impact upon gadolinium administration on the conspicuity of active enhancing multiple sclerosis (MS) lesions using double inversion recovery (DIR) at 3T.

METHODS

15 consecutive patients with MS (n=8) or a clinically isolated syndrome (n=7) underwent pre and post-contrast DIR in addition to T2-weighted, FLAIR, pre and post-contrast T1-weighted sequences. First, two neuroradiologists located and marked all the enhancing MS lesions visible in consensus. Second, two other neuroradiologists, blinded to other sequences than DIR, independently assessed the SI changes from pre to post-contrast DIR images for each enhancing lesion, according to a 4-point-scale: increased SI (grade 1), absence of change (grade 2), lesion being partially (grade 3) or completely masked on post-contrast DIR images (grade 4).

RESULTS

246 MS lesions were detected including 26 enhancing on post-contrast T1-weighted images in 9 patients. The two blinded readers concluded to a decreased signal-intensity on post-contrast DIR images for all the 26 enhancing MS lesions (14 of grade 3 and 12 of grade 4). Inter-observer agreement was excellent, Kappa=0.85 (0.75 - 0.94). Using DIR post-contrast leads to altered signal-intensity of enhancing active MS lesions, ranging from partial to complete signal-loss.

CONCLUSION

Our study strongly suggests the use of DIR before gadolinium administration.

KEY POINTS

• DIR has gained widespread use in MS. • MRI protocols for MS patients usually contain several post-contrast sequences. • Signal-intensity of enhancing MS lesions is altered using DIR post-contrast. • Our study strongly suggests the use of DIR before gadolinium administration.

Punctate and curvilinear gadolinium enhancing lesions in the brain: a practical approach

INTRODUCTION

Cerebral punctate and curvilinear gadolinium enhancements (PCGE) correspond to opacification of small vessel lumen or its perivascular areas in case of blood-brain barrier (BBB) disruption. We will discuss the possible causes of intra-parenchymal central nervous system PCGE.

METHODS

Our review is based on French database including patients presenting with central nervous system PCGE and literature search using PubMed database with the following keywords: punctate enhancement, linear enhancement, and curvilinear enhancement. Disorders which displayed linear leptomeningeal or periventricular enhancements without intra-parenchymal PCGE are excluded of this review.

RESULTS

Among our 39 patients with PCGE, 16 different diagnoses were established. After combining our PCGE causes with those described in the literature, we propose a practical approach. Besides physiologic post-contrast enhancement of small vessels, three pathologic conditions may exhibit PCGE: (1) small collateral artery network seen in Moyamoya syndrome, (2) small veins congestions related to developmental or acquired venous outflow disturbance, and (3) disorders causing small vessels BBB disruption indicated by T2 and FLAIR hyperintensities in the corresponding areas of PCGE. Disruption of the BBB could be caused by a direct injury of the endothelial cell, as in posterior reversible encephalopathy syndrome, Susac syndrome, and radiochemotherapy-induced injuries, or by an angiocentric cellular infiltrate, as in inflammatory disorders, demyelinating diseases, host immune responses fighting against infections, prelymphoma states, lymphoma, and in CLIPPERS.

CONCLUSION

PCGE may conceal several causes, including physiological and pathological conditions. Nevertheless, a practical approach could improve its management and limit the indications of brain biopsy to very specific situations.

Evidence-based guidelines: MAGNIMS consensus guidelines on the use of MRI in multiple sclerosis-clinical implementation in the diagnostic process

The clinical use of MRI in patients with multiple sclerosis (MS) has advanced markedly over the past few years. Technical improvements and continuously emerging data from clinical trials and observational studies have contributed to the enhanced performance of this tool for achieving a prompt diagnosis in patients with MS. The aim of this article is to provide guidelines for the implementation of MRI of the brain and spinal cord in the diagnosis of patients who are suspected of having MS. These guidelines are based on an extensive review of the recent literature, as well as on the personal experience of the members of the MAGNIMS (Magnetic Resonance Imaging in MS) network. We address the indications, timing, coverage, reporting and interpretation of MRI studies in patients with suspected MS. Our recommendations are intended to help radiologists and neurologists standardize and optimize the use of MRI in clinical practice for the diagnosis of MS.

MRI in multiple sclerosis: an intra-individual, randomized and multicentric comparison of gadobutrol with gadoterate meglumine at 3 T

OBJECTIVES

To compare contrast effects of gadobutrol with gadoterate meglumine for brain MRI in multiple sclerosis (MS) in a multicentre, randomized, prospective, intraindividual study at 3 T.

METHODS

Institutional review board approval was obtained. Patients with known or suspected active MS lesions were included. Two identical MRIs were performed using randomized contrast agent order. Four post-contrast T1 sequences were acquired (start time points 0, 3, 6 and 9 min). If no enhancing lesion was present in first MRI, second MRI was cancelled. Quantitative (number and signal intensity of enhancing lesions) and qualitative parameters (time points of first and all lesions enhancing; subjective preference regarding contrast enhancement and lesion delineation; global preference) were evaluated blinded.

RESULTS

Seventy-four patients (male, 26; mean age, 35 years) were enrolled in three centres. In 45 patients enhancing lesions were found. Number of enhancing lesions increased over time for both contrast agents without significant difference (median 2 for both). Lesions signal intensity was significantly higher for gadobutrol (p < 0.05 at time points 3, 6 and 9 min). Subjective preference rating showed non-significant tendency in favour of gadobutrol.

CONCLUSION

Both gadobutrol and gadoterate meglumine can be used for imaging of acute inflammatory MS lesions. However, gadobutrol generates higher lesion SI.

KEY POINTS

Contrast-enhanced MRI plays a key role in the management of multiple sclerosis. Different gadolinium-based contrast agents are available. Number of visibly enhancing lesions increases over time after contrast injection. Gadobutrol and gadoterate meglumine do not differ in number of visible lesions. Gadobutrol generates higher signal intensity than gadoterate meglumine.

Stage-specific immune dysregulation in multiple sclerosis

A large body of data indicates that multiple sclerosis (MS) is an autoimmune disease which is initiated by CD4(+) T-helper 1 (Th1) and Th17 cells that are reactive against proteins in the myelin sheath. MS typically begins with a relapsing-remitting course, punctuated by clinical exacerbations associated with the development of focal inflammatory lesions in central nervous system white matter, followed by a secondary progressive (SP) phase, characterized by a gradual accumulation of neurological disability associated with widespread microglial activation and axonal loss. The molecular and cellular basis for this transition is unclear, and the role of inflammation during the SP stage is a subject of active debate. As of now, no immunological biomarkers have been identified in MS that are predictive of the clinical course or therapeutic responsiveness to disease-modifying agents, or that correlate with new lesion development, cumulative lesion load, or degree of disability. The discovery of such biomarkers would greatly facilitate clinical management and provide power for smaller and shorter clinical trials. In this article, we discuss the literature on immunological biomarkers in MS with a focus on stage-specific differences and similarities.

MS lesions are better detected with 3D T1 gradient-echo than with 2D T1 spin-echo gadolinium-enhanced imaging at 3T

BACKGROUND AND PURPOSE

In multiple sclerosis, gadolinium enhancement is used to classify lesions as active. Regarding the need for a standardized and accurate method for detection of multiple sclerosis activity, we compared 2D-spin-echo with 3D-gradient-echo T1WI for the detection of gadolinium-enhancing MS lesions.

MATERIALS AND METHODS

Fifty-eight patients with MS were prospectively imaged at 3T by using both 2D-spin-echo and 3D-gradient recalled-echo T1WI in random order after the injection of gadolinium. Blinded and independent evaluation was performed by a junior and a senior reader to count gadolinium-enhancing lesions and to characterize their location, size, pattern of enhancement, and the relative contrast between enhancing lesions and the adjacent white matter. Finally, the SNR and relative contrast of gadolinium-enhancing lesions were computed for both sequences by using simulations.

RESULTS

Significantly more gadolinium-enhancing lesions were reported on 3D-gradient recalled-echo than on 2D-spin-echo (n = 59 versus n = 30 for the junior reader, P = .021; n = 77 versus n = 61 for the senior reader, P = .017). The difference between the 2 readers was significant on 2D-spin-echo (P = .044), for which images were less reproducible (κ = 0.51) than for 3D-gradient recalled-echo (κ = 0.65). Further comparisons showed that there were statistically more small lesions (<5 mm) on 3D-gradient recalled-echo than on 2D-spin-echo (P = .04), while other features were similar. Theoretic results from simulations predicted SNR and lesion contrast for 3D-gradient recalled-echo to be better than for 2D-spin-echo for visualization of small enhancing lesions and were, therefore, consistent with clinical observations.

CONCLUSIONS

At 3T, 3D-gradient recalled-echo provides a higher detection rate of gadolinium-enhancing lesions, especially those with smaller size, with a better reproducibility; this finding suggests using 3D-gradient recalled-echo to detect MS activity, with potential impact in initiation, monitoring, and optimization of therapy.

Evaluation of plaque detection and optimum time of enhancement in acute attack multiple sclerosis after contrast injection

BACKGROUND

Magnetic resonance imaging (MRI) is important in the early diagnosis of novel or relapsing multiple sclerosis (MS). In addition, the optimal MRI protocol plays an important role in detecting MS plaques.

PURPOSE

To find the best time to detect MS plaques on MRI after Gadobutrol injection.

MATERIAL AND METHODS

Sixty-two relapsing-remitting type MS patients, (56 women, 6 men) with the mean age of 31 ± 7 years were enrolled into this study. The patients underwent T1-weighted MRI scan without contrast agents. Subsequently, Gadobutrol was injected (0.1 mmol/kg) and MRI scanning was repeated after 30 s, 5, 10, 15, and 30 min of Gadobutrol injection. The size, signal intensity, and enhancement pattern were determined for each plaque by contrast-enhanced T1-weighted images.

RESULTS

Enhancing plaques were seen in 42 out of 62 patients. The mean number of enhancing plaques was 4 ± 8 plaques after 30 s of contrast injection. This figure increased to 7 ± 13 plaques after 15 min and 6 ± 10 plaques after 30 min. The signal intensity and size of plaques increased progressively, and the maximum signal intensity and plaque size were seen after 30 min (P < 0.001).

CONCLUSION

The maximum number of enhancing plaques in MS patients was detected 15 min after contrast agent administration and the size and signal intensity of the lesions also increased remarkably at this time.

Effect of imaging time in the magnetic resonance detection of intracerebral metastases using single dose gadobutrol

OBJECTIVE

To compare the effect of imaging time delay on the MR detection of intracerebral metastases using single dose gadobutrol.

MATERIALS AND METHODS

Twenty-one patients with intracerebral metastases underwent contrast-enhanced MR with three-dimensional T1-weighted sequence at 1 minute, 5 minutes and 10 minutes after a single dose injection of gadobutrol. One hundred index metastatic lesions (1 to 30 mm; median, 7 mm) were chosen for the analysis. For the qualitative analysis, lesion conspicuity were assessed on a 1 (worst) to 5 (best) scale of the index lesions by an expert reader. For the quantitative analysis, signal intensity (SI) of enhancing lesions and normal parenchyma was measured to determine the contrast rate (CR, %) ([postcontrast SI lesion - postcontrast SI white matter] × 100 / postcontrast SI white matter) and the enhancement rate (ER, %) ([postcontrast SI lesion - baseline SI gray matter] × 100 / baseline SI gray matter). Statistical comparisons were made between three different time delays.

RESULTS

Lesion conspicuity did not differ significantly among the three time delays (p = 0.097). Although the SI, CR and ER of lesions did not reveal any significant difference between 1 minute and 5 minutes delayed images, both the 1 minute and 5 minutes delayed images showed significantly higher CRs of lesions compared with the 10 minutes delayed images (p = 0.004 and p = 0.001, respectively).

CONCLUSION

With single dose gadobutrol, imaging time delay did not have an effect on lesion conspicuity. Both 1-minute and 5-minute-delayed imaging after gadobutrol injection appears to be effective for the detection of intracerebral metastases.

Accuracy of postcontrast 3D turbo spin-echo MR sequence for the detection of enhanced inflammatory lesions in patients with multiple sclerosis

BACKGROUND AND PURPOSE

Therapeutic strategies for patients with MS partly rely on contrast-enhanced MR imaging. Our aim was to assess the diagnostic performance of 3D turbo spin-echo MR imaging with variable refocusing flip angles at 3T for the detection of enhanced inflammatory lesions in patients with multiple sclerosis.

MATERIALS AND METHODS

Fifty-six patients with MS were prospectively investigated by using postcontrast T1-weighted axial 2D spin-echo and 3D TSE MR images. The order in which both sequences were performed was randomized. Axial reformats from 3D T1 TSE were generated to match the 2D spin-echo images. The reference standard was defined by using clinical data and all MR images available. Three separate sets of MR images (2D spin-echo images, axial reformats, and multiplanar images from 3D TSE sequences) were examined in a blinded fashion by 2 neuroradiologists separately for the detection of enhanced MS lesions. Image artifacts and contrast were evaluated.

RESULTS

No artifacts related to vascular pulsation were observed on 3D TSE images, whereas image artifacts were demonstrated on 2D spin-echo images in 41 patients. One hundred twelve enhanced MS lesions were identified in 19 patients. Sixty-four lesions were correctly diagnosed by using 2D spin-echo images; 90, by using 3D TSE axial reformatted views; and 106, by using multiplanar analysis of the 3D TSE sequence. Multiplanar analysis was 94.7% sensitive and 100% specific for the diagnosis of patients with at least 1 enhanced lesion. Contrast of enhanced MS lesions was significantly improved by using the 3D TSE sequence (P < .011).

CONCLUSIONS

The 3D TSE sequence with multiplanar analysis is a useful tool for the detection of enhanced MS lesions.

Is it possible to detect active multiple sclerosis plaques using MR thermometry techniques?

Multiple sclerosis lesions or plaques are considered to be the result of an inflammatory process in the brain that leads to attack myelin. Inflammation causes disruption of blood-brain barrier in acute, active plaque areas. This process may lead to increase blood supply that causes increase in temperature in these associated areas. These plaques can be seen by examining the brain using magnetic resonance imaging (MRI). Presence of these plaques plays an important role in indicating dissemination in time within the new diagnostic criteria and in treatment of active MS. Gadolinium-based contrast agents help for quantitative assessment of inflammatory activity and lesion load. However, these agents have serious risks such as anaphylaxis and kidney damage. We wanted to open up a discussion for the feasibility of using noninvasive MR thermometer technique instead of conventional MRI techniques, for evaluating the temperature and the extent of temperature changes of white matter and plaques in MS patients. After successful using of MR thermometer technique with upgraded applications, the time needed to perform the studies in a routine setting can be significantly shortened. With eliminating usage of contrast agent, considerable influx money can be provided along with preventing the adverse effects and risks of contrast agent usage.

MR imaging of neoplastic central nervous system lesions: review and recommendations for current practice

MR imaging is the preferred technique for the diagnosis, treatment planning, and monitoring of patients with neoplastic CNS lesions. Conventional MR imaging, with gadolinium-based contrast enhancement, is increasingly combined with advanced, functional MR imaging techniques to offer morphologic, metabolic, and physiologic information. This article provides updated recommendations to neuroradiologists, neuro-oncologists, neurosurgeons, and radiation oncologists on the practical applications of MR imaging of neoplastic CNS lesions in adults, with particular focus on gliomas, based on a review of the clinical trial evidence and personal experiences shared at a recent international meeting of experts in neuroradiology, neuro-oncology, neurosurgery, and radio-oncology.

MR imaging in multiple sclerosis: review and recommendations for current practice

MR imaging is widely used for the diagnosis and monitoring of patients with MS. Applications and protocols for MR imaging continue to evolve, prompting a need for continual reassessments of the optimal use of this technique in clinical practice. This article provides updated recommendations on the use of MR imaging in MS, based on a review of the trial evidence and personal experiences shared at a recent expert meeting of radiologists and neurologists.

Diagnostic value of contrast-enhanced fluid-attenuated inversion-recovery and delayed contrast-enhanced brain MRI in multiple sclerosis

RATIONALE AND OBJECTIVES

In brain MRI of multiple sclerosis (MS) patients, enhancement of the lesions is usually evaluated in early contrast-enhanced T1-weighted images (CE-T1WI). The objective of this study is to determine the sensitivity of contrast-enhanced fluid-attenuated-inversion-recovery (CE-FLAIR) and delayed contrast-enhanced MRI in evaluation of MS brain lesions.

MATERIALS AND METHODS

Brain MRI examination including early and delayed CE-T1WI and early and delayed CE-FLAIR images was performed for 46 patients with clinically definite MS disease. Number, size, location, degree, and pattern of enhancement of the enhanced lesions in each sequence were recorded separately.

RESULTS

A total number of 87 enhanced lesions was detected in 30 patients. Early CE-T1WI could detect only 63 lesions (72.4% of total) in 24 patients, while delayed CE-T1WI and early and delayed CE-FLAIR images showed 85 (97.7%), 84 (96.6%), and 81 (93.1%) lesions in 28, 28, and 26 patients, respectively. A greater degree of enhancement and larger lesion size were observed in the additional sequences compared with the early CE-T1WI.

CONCLUSIONS

The sensitivity of early CE-T1WI for the detection of enhanced MS lesions is significantly lower than that for other additional sequences. Delayed CE-FLAIR images could not add significant information to other sequences. Therefore, early CE-FLAIR and delayed CE-T1WI brain MRI can be considered as part of the evaluation of MS patients, especially if, despite clinically suspected active disease, no enhanced lesion is found in the routine CE-T1WI.