Multiple sclerosis (MS) is the most common demyelinating and neurodegenerative inflammatory disease in adults between 18 and 35 years of age and constitutes the second cause of neurological disability in young adults.¹

This pathology is considered an autoimmune organ specific disorder, characterized by multiple focal areas of demyelination called plaques or lesions, which are accompanied by different degrees of gliosis, inflammation, and neuroaxonal damage.²

In the examination and diagnosis of MS, MRI is a crucial tool. Multiple, hyper-intense plaques characterize MS plaques in T2 Weighted Images (WI) and Fluid Attenuated Inversion Recovery (FA IR) (FL AIR). T1WI lesions with low intensity ("black holes") are linked to myelin atrophy. Contrast-enhancing lesions indicate a breakdown of the blood-brain barrier due to acute inflammation; if managed with steroids, enhancement can last for 2 to 6 weeks. 3 & 4

In early and asymptomatic MS plaques, MRI has a high sensitivity. The sensitivity of MRI for spinal cord injuries ranges amongst articles, ranging from 68 to 89 percent. 1

MS plaques generally occur in the white matter although 10% of the plaques are seen in the gray matter. The MS plaques are generally seen in the capsula interna, periventricular white matter, corpus callosum and pons.⁵

The Apparent Diffusion Coefficient (A D C) of water in the brain can be measured using a Diffusion Weighted Image (D W I). Water diffusion in the brain is regulated by cellular borders, and any breakdown in cellular structure raises the A D C. ⁶

The random translational motion of molecules caused by their internal thermal energy is known as diffusion. It is now possible to derive information on the structural organization of tissues well beyond the spatial resolution of standard M R imaging techniques thanks to the advancement of M R quantifiable diffusion effects. Spin echo-based sequences are used in DWI, and high magnetic field gradient pulses are used to sensitize diffusion. ⁷

The goal of the study was to use diffusion weighted imaging and the ADC value to assess asymptomatic or inactive multiple sclerosis plaques.

PATIENTS AND METHODS

We evaluated prospectively 50 patients with known multiple sclerosis and fulfilled McDonald Criteria 2017. Patients of interest were recruited from the Neurology department in Al-Azhar University Hospitals during two years (May 2020 to May 2022). Clinical diagnosis was performed by an expert neurologist with 10 years of experience in treating MS.

Inclusion criteria: Both female and male with age group (20 – 45) years old who were referred with multiple sclerosis remission state (asymptomatic patients) for follow up and other symptomatic patients with multiple sclerosis were enrolled in the study.

Exclusion criteria: Patients known to have contraindications for MRI, e.g. an implanted magnetic device, pacemakers, patients who have claustrophobia, patients with past history of intracranial surgical interference, patients with bad general condition needing life support, and patients with other forms of MS and patients for whom there were no MRI images were excluded from the study.

Ethical considerations: Oral and written consents were obtained from all patients prior to inclusion them in the study. The study was conducted according to the stipulations of Al-Azhar university ethical and scientific committee.

Patient preparation:

Full history taking from each patient including name, gender, age, complain, duration of the disease, treatment. And clinical examination done by the neurologist.

Detailed explanation of imaging procedure. Removal of cards and any other metal containing objects. Contrast injection benefits and risks was explained to the patient before the scan. Fasting for 6 – 8 hours and checking serum creatinine before Gadolinium administration. Measuring patient body weight for calculation of amount of contrast media, and instruct the patient to keep calm.

Conventional MRI was done using a phased array head coil, with 1.5 Tesla MRI scanner (Philips achieva XR). In Al-Azhar University Imaging Unit.

Statistical analysis:

Recorded data were analyzed using the statistical package for social sciences, version 20.0 (SPSS Inc., Chicago, Illinois, USA). Quantitative data were expressed as mean± standard deviation (SD). Qualitative data were expressed as frequency and percentage. Independent-samples t-test of significance was used when comparing between two means. Chi-square (x²) test of significance was used in order to compare proportions between qualitative parameters. Receiver operating characteristic (ROC curve) analysis was used to find out the overall predictivity of parameter in and to find out the best cut-off value with detection of sensitivity and specificity at this cut-off value. The confidence interval was set to 95% and the margin of error accepted was set to 5%. P value < 0.05 was considered significant.

RESULTS

Using: x2: Chi-square test;      p-value>0.05 NS; *p-value

Table 1: Comparison between symptomatic group and asymptomatic group according to plaques distribution about number of patients.

There was a significant difference in the sites of M.S plaques in spinal cord and cerebellar peduncles between symptomatic and asymptomatic groups P< 0.05. While no significant difference in the subcortical, juxtacortical, periventricular and brain stem P>0.05 (Table 1).

Using: x2: Chi-square test;      p-value>0.05 NS; *p-value

Table 2: Comparison among number of M.S plaques in differents sites between symptomatic group and asymptomatic groups.

There was a statistically significant difference between number of MS plaques in between symptomatic and asymptomatic patients in subcortical, spinal cord and cerebellar peduncles in all these sites the number of plaques were more in symptomatic patients P0.05 (Table 2).

Using: t=Independent Sample t-test; x2: Chi-square test; p-value>0.05 NS; *p-value

Table 3: Comparison among M.S plaques regarding MRI finding between symptomatic and asymptomatic groups.

There was a statistically significant difference between diameters of M.S plaques between symptomatic and asymptomatic groups, p-value (p<0.05). The diameter was more in symptomatic group. There was no statistically significant difference in the MRI sequences finding of M.S plaques between symptomatic and asymptomatic patients, P >0.05) (Table 3).

Using: x2: Chi-square test; p-value >0.05 NS

Table 4: Comparison M.S plaques MRI ADC finding between symptomatic group and asymptomatic group.

There was no significant difference in the number of restricted M.S plaques between symptomatic and asymptomatic patients P >0.05), restricted plaques (hyper intense in DWIb1000 and hypo intense in ADC) were more in symptomatic patients then in asymptomatic patient with not reaching statistical difference (Table 4).

Using: t=Independent Sample t-test; **p-value

Table 5: Comparison between symptomatic group and asymptomatic group regarding ADC value x (10−3 mm2/s) in the Shine Through plaques.

The mean value of ADC was higher in symptomatic patients than in asymptomatic patients 1.43±0.21 and 1.18±0.19 x (10−3 mm2/s) respectively with high significant difference P

Table 6: Comparison between ADC value of restricted M.S plaques between symptomatic group and asymptomatic group.

There was no important variance in the A DC value of the restricted M.S plaques in both symptomatic and asymptomatic patient P>0.05 (Table 6).

Table 7: Comparison between symptomatic group and asymptomatic group regarding enhancement of M.S plaques in post contrast T1 MRI sequence and DWI appearance.

T1post contrast enhancement of M.S plaques was more detected in the symptomatic patients than in asymptomatic patient as well as the restricted plaques were more in symptomatic than in asymptomatic patients but with no important variance in P >0. 05 (Table 7).

Fig. 1: Receiver-operating characteristic (ROC) curve for a prediction of activity of the disease using ADC value x (10−3 mm2/s).

Receiver operator characteristics (R OC) curves for ADC value x (10−3 mm2/s) as a predictor of activity of the M.S disease in enrolled patients. ADC value x (10−3 mm2/s) indices were significant predictors as denoted by the significantly large area under the curves (AUCs), there was used to define the best cut off value of ADC value x (10−3 mm2/s) which was ≥1.292, with sensitivity of 82.1% specificity of 82.6% positive predictive value of 85.2%, negative predictive value of 79.2%, diagnostic area under the curve of 0.828 with p-value

CASES

Case (1): 38 years old male with 4 years history of multiple sclerosis, presented with limb weakness at time examination;

Figure (2): MRI shows presence of about 40 MS plaques, supratentonrial, biggest plaque was 9 mm, appears hyperintense in T2W, hyperintense in FLAIR, hypointense in T1W, not enhanced post contrast, shine through in ADC, it’s value was 1.45 x 10-3mm2/s

Case (2): 33 years old male had history of MS for 2 years, in remission state presented for follow up,

Figure (3): MRI findings were presence of 22 MS plaques, supratentorial, biggest one 12 mm, appears hyperintense in T2W and FLAIR, isointense inT1W, hyperintense in ADC, its value was 1.11 x 10-3 mm2/s.