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

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.

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).

Importance of Contrast-Enhanced Fluid-Attenuated Inversion Recovery Magnetic Resonance Imaging in Various Intracranial Pathologic Conditions

Intracranial lesions may show contrast enhancement through various mechanisms that are closely associated with the disease process. The preferred magnetic resonance sequence in contrast imaging is T1-weighted imaging (T1WI) at most institutions. However, lesion enhancement is occasionally inconspicuous on T1WI. Although fluid-attenuated inversion recovery (FLAIR) sequences are commonly considered as T2-weighted imaging with dark cerebrospinal fluid, they also show mild T1-weighted contrast, which is responsible for the contrast enhancement. For several years, FLAIR imaging has been successfully incorporated as a routine sequence at our institution for contrast-enhanced (CE) brain imaging in detecting various intracranial diseases. In this pictorial essay, we describe and illustrate the diagnostic importance of CE-FLAIR imaging in various intracranial pathologic conditions.

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.

Cerebral lesions of multiple sclerosis: is gadolinium always irreplaceable in assessing lesion activity?

PURPOSE

We aimed to identify imaging characteristics on conventional magnetic resonance imaging that could predict multiple sclerosis (MS) brain lesion activity without contrast media administration.

MATERIALS AND METHODS

Magnetic resonance data sets of forty-two patients with relapsing-remitting MS who presented symptoms or signs suggestive of new disease activity were retrospectively reviewed. We classified the MS lesions into three types according to different patterns present on T2-weighted images and evaluated their relationship with the contrast uptake. Evolving aspects of each type of lesion were observed in 18 patients during a follow-up period ranging from nine to 36 months.

RESULTS

On T2-weighted images, only the pattern consisting of a thin border of decreased intensity compared with the lesion's center and perifocal edema (Type II) reached diagnostic accuracy in terms of its relationship with gadolinium enhancement (P = 0.006). The sensitivity was 0.461, and the specificity was 0.698. In contrast, enhancement was not significantly related to the pattern consisting of a lesion center that was homogeneously brighter than its periphery (Type I) or less-hyperintense T2 focal lesions with either homogeneous or inhomogeneous center (Type III) (P > 0.05 for both).

CONCLUSION

The assessment of MS lesion activity should include a careful evaluation of T2-weighted images in addition to contrast enhancement assessment. The presence of an accompanying peripheral thin rim of hypointensity on T2-weighted images related best with contrast enhancement and subsequent lesion activity and may represent an additional pattern for disease activity assessment when gadolinium examination is contraindicated or influenced by prior therapy.

Contrast-enhanced MR imaging in neuroimaging

MR imaging without and with gadolinium-based contrast agents (GBCAs) is an important imaging tool for defining normal anatomy and characteristics of lesions. GBCAs have been used in contrast-enhanced MR imaging in defining and characterizing lesions of the central nervous system for more than 20 years. The combination of unenhanced and GBCA-enhanced MR imaging is the clinical gold standard for the noninvasive detection and delineation of most intracranial and spinal lesions. MR imaging has a high predictive value that rules out neoplasm and most inflammatory and demyelinating processes of the central nervous system.

Evolution of the blood-brain barrier in newly forming multiple sclerosis lesions

OBJECTIVE

Multiple sclerosis (MS) lesions develop around small, inflamed veins. New lesions enhance with gadolinium on magnetic resonance imaging (MRI), reflecting disruption of the blood-brain barrier (BBB). Single time point results from pathology and standard MRI cannot capture the spatiotemporal expansion of lesions. We investigated the development and expansion of new MS lesions, focusing on the dynamics of BBB permeability.

METHODS

We performed dynamic contrast-enhanced (DCE) MRI in relapsing-remitting MS. We obtained data over 65 minutes, during and after gadolinium injection. We labeled spatiotemporal enhancement dynamics as centrifugal when initially central enhancement expanded outward and centripetal when initially peripheral enhancement gradually filled the center.

RESULTS

We detected 34 enhancing lesions in 200 DCE-MRI scans. In 65%, enhancement first appeared as a closed ring; in 18%, as a nodule; and in 18%, as an open ring. Lesions with initially nodular enhancement were smaller than those initially enhancing as rings (p < 0.0001). All initially nodular lesions enhanced centrifugally, whereas initially ringlike lesions enhanced centripetally, becoming nodular if small (82%) or nearly nodular if larger (18%). Open-ring lesions were periventricular or juxtacortical and enhanced centripetally. Centrifugally enhancing lesions evolved into centripetally enhancing lesions over several days.

INTERPRETATION

The rapid change of enhancement dynamics from centrifugal to centripetal reflects the outward growth of MS lesions around their central vein and suggests that factors mediating lesion growth and tissue repair derive from different locations at different times. We propose a model of new lesion growth that unites our imaging observations with existing pathology data.

Blood-brain barrier disruption in humans is independently associated with increased matrix metalloproteinase-9

BACKGROUND AND PURPOSE

Matrix metalloproteinases (MMP) may play a role in blood-brain barrier (BBB) disruption after ischemic stroke. We hypothesized that plasma concentrations of MMP-9 are associated with a marker of BBB disruption in patients evaluated for acute stroke.

METHODS

Patients underwent MRI on presentation and approximately 24 hours later. The MRI marker, termed hyperintense acute reperfusion injury marker (HARM), is gadolinium enhancement of cerebrospinal fluid on fluid-attenuated inversion recovery MRI. Plasma MMP-9 and tissue inhibitor of matrix metalloproteinase-1 were measured by enzyme-linked immunosorbent assay. Logistic regression models tested for predictors of HARM on 24-hour follow-up scans separately for MMP-9 and the ratio of MMP-9 to TIMP-1.

RESULTS

For the 41 patients enrolled, diagnoses were: acute ischemic cerebrovascular syndrome, 33 (80.6%); intracerebral hemorrhage, 6 (14.6%); stroke mimic, 1 (2.4%); and no stroke, 1 (2.4%). HARM was present in 17 (41.5%) patients. In model 1, HARM was associated with baseline plasma MMP-9 concentration (odds ratio [OR], 1.01; 95% confidence interval [CI], 1.001-1.019; P=0.033). In model 2, HARM was associated with the ratio of MMP-9 to tissue inhibitor of matrix metalloproteinase-1 (OR, 4.94; 95% CI, 1.27-19.14; P=0.021).

CONCLUSIONS

Baseline MMP-9 was a significant predictor of HARM at 24-hour follow-up, supporting the hypothesis that MMP-9 is associated with BBB disruption. If the association between MMP-9 and BBB disruption is confirmed in future studies, HARM may be a useful imaging marker to evaluate MMP-9 inhibition in ischemic stroke and other populations with BBB disruption.

Early contrast-enhanced magnetic resonance imaging with fluid-attenuated inversion recovery in multiple sclerosis

OBJECTIVE

Contrast-enhanced magnetic resonance imaging (MRI) with fluid-attenuated inversion recovery (contrast FLAIR) is particularly useful for the detection of meningeal lesions. However, whether contrast FLAIR is useful in multiple sclerosis (MS) remains uncertain. This study evaluated the usefulness of contrast FLAIR in MS.

PATIENTS AND METHODS

We prospectively studied the clinical histories and brain MRI studies of 6 patients with clinically definite MS diagnosed according to the new McDonald criteria. Contrast FLAIR (repetition time [TR] 9,000 ms; echo time [TE] 120 ms; inversion time [TI] 2,200 ms; 5-mm slice thickness, with a 1-mm interslice gap) was obtained with the use of a bolus of gadolinium diethylenetriamine pentaacetic acid.

RESULTS

Three enhancing plaques located in the periventricular or juxtacortical areas showed higher intensity on contrast FLAIR than on other MR sequences. In contrast, 8 enhancing plaques in the deep white matter or infratentorial areas showed no increased signals on contrast FLAIR.

CONCLUSION

Our findings suggest that early contrast-enhanced imaging with FLAIR may be helpful for the further detection of MS plaques, particularly those located in periventricular and juxtacortical lesions.