Slobodan Lavrnic

Brain iron MRI: A biomarker for amyotrophic lateral sclerosis

To evaluate the usefulness of MRI detection of hypointensity areas (iron deposits) in the brain using a dedicated MRI technique in patients with ALS in establishing this sign as a potential surrogate biomarker that correlates with the severity of disease.

The predictive value of the presence of different antibodies and thymus pathology to the clinical outcome in patients with generalized myasthenia gravis

OBJECTIVES To analyze the predictive value of anti-acetylcholine receptor antibodies (anti-AChR Ab) and anti-muscle specific kinase antibodies (anti-MuSK Ab), as well as the thymus pathology to the clinical outcome in patients with generalized myasthenia gravis (MG). METHODS We analyzed 138 patients with generalized MG, who were thymectomized and assayed for anti-AChR Ab and anti-MuSK Ab. RESULTS Anti-AChR Ab were detected in 84% of patients, while anti-MuSK Ab were present in 36% of the AChR Ab negative patients. Severe forms of the disease were more frequent in MuSK Ab positive, compared to the AChR Ab positive and complete seronegative patients. Thymic lymphoid follicular hyperplasia (LFH) was present in 60%, thymoma in 23%, atrophic thymus in 9% and the normal thymus in 8% of patients. LFH was more frequent among women, while thymoma and atrophic thymus were more frequent in men. The younger patients mainly had LFH and normal thymus, while thymoma and atrophic thymus were more frequent in older patients. The mildest clinical presentation was present in patients with normal thymus, while severe forms of the disease were registered in the patients with thymoma. The AChR Ab positive patients had more often LFH and thymoma, while within MuSK Ab positive patients atrophic thymus was most common. CONCLUSION The best disease outcome was observed in patients with normal thymus or LFH with anti-AChR Ab or without both types of antibodies.

Significance of magnetic resonance imaging in differential diagnosis of nontraumatic brachial plexopathy.

BACKGROUND/AIM Nontraumatic brachial plexopathies may be caused by primary or secondary tumors, radiation or inflammation. The aim of this study was to present the significance of MRI in revealing the cause of nontraumatic brachial plexopathy. METHODS A two-year retrospective study included 22 patients with nontraumatic brachial plexopathy. In all the patients typical clinical findings were confirmed by upper limb neurophysiological studies. In all of them MRI of brachial plexus was performed by 1.5 T scanner in T1 and T1 FS sequence with and without contrast, as well as in T2 and T2 FS sequences. RESULTS Seven (32%) patients had brachial plexopathy with signs of inflammatory process, 5 (23%) patients had secondary tumors, in 4 (18%) patients multifocal motor neuropathy was established and in the same number (18%) of the patients postradiation fibrosis was found. Two patients (9%) had primary neurogenic tumors. CONCLUSION According to the results of this study MRI is a method which may determine localization and cause of brachial plexopathy. MRI can detect focal nerve lesions when other methods fail to find them. Thus, MRI has a direct impact on further diagnostic and therapeutical procedures.

Proton magnetic resonance spectroscopy of the intrinsic tongue muscles in patients with myasthenia gravis with different autoantibodies

OBJECTIVE To assess lipid composition of the intrinsic tongue muscles in patients with myasthenia gravis (MG). METHODS This study included 15 MG patients with antibodies against muscle-specific kinase (MuSK), 15 matched MG patients with antibodies against acetylcholine receptor (AChR) and 15 matched healthy subjects. Middle posterior region of the tongue was analyzed by single voxel point-resolved proton magnetic resonance spectroscopy (MRS) using 1.5T MRI scanner. RESULTS MRS obtained from subject with AChR MG showed a broad resonance arising from methylene groups of lipids (PMN) with no observable shoulder attributed to methyl groups (PML). Full-width at half maximum (FWHM) of PMN+PML peak showed higher value in patients with AChR MG in comparison to healthy subjects and MuSK MG patients (p<0.05). In patients with MuSK MG, the shape and FWHM of PMN+PML peak was similar as in healthy subjects (p>0.05), with tendency toward increased ratio between PMN and resonance from vinyl protons of lipids (PV). In both AChR and MuSK MG, total creatine resonance (creatine+phosphocreatine, CP) was almost absent with significant increase of PMN/CP ratio in comparison to healthy subjects (p<0.05). CONCLUSION MRS is useful in revealing muscle lipid composition in MG. In patients with AChR MG, MRS showed increased lipid content in the tongue muscles due to the lipid migration from intra- to extramyocellular space. Finding in patients with MuSK MG might reflect intramyocellular lipid deposition in the tongue. CP decrease in tongue muscles indicated impairment of oxidative metabolism in both AChR MG and MuSK MG.

Bálint-like syndrome as an unusual representation of non-convulsive status epilepticus

The clinical signs of posterior cortex dysfunction are, due to their paucity and subtlety, very often ignored as non-specific during clinical evaluation of non-convulsive status epilepticus. Therefore, focal non-convulsive status epilepticus emerging from the posterior cortex, and especially the parietal lobes, can be fairly under-recognised. We report a 66-year-old patient with focal non-convulsive status epilepticus presenting as isolated Bálint-like syndrome, successfully treated to full clinical and electrophysiological recovery. The diagnostic and pathophysiological features are discussed. Focal non-convulsive status epilepticus can be associated with negative phenomena such as neuropsychological deficits mimicking those detected more often in degenerative and vascular brain diseases.

Proton magnetic resonance spectroscopy and apparent diffusion coefficient in evaluation of solid brain lesions

BACKGROUND/AIM Advanced magnetic resonance techniques can provide insight in physiological changes within pathological canges and contribute to better distinquishing between different tumor types and their discrimination from non-neoplastic lesions. The aim of this study was to evaluate the role of proton magnetic resonance spectroscopy (1H-MRS) and apparent diffusion coefficients (ADC) in distinguishing intracranial glial tumors from tumor like nonneoplastic lesions, as well as for differentiating high- from low-grade gliomas. METHODS This retrospective study included 47 patients with solid brain lesions (25 nonneoplastic, 14 low-grade and 8 anaplastic glial tumors). In all patients 1H-MRS (at a TE of 135 ms and 30 ms) and diffusion-weighted imaging (DWI) were performed. The choline to creatine (Cho/Cr), choline to N-acetyl aspartate (Cho/NAA), N-acetyl aspartate to creatine (NAA/Cr) and myoinositol to creatine (mIn/Cr) ratios and the apparent diffusion coefficient (ADC) were determined. RESULTS The Cho/Cr ratio was significantly higher in glial tumors grade II than in non-neoplastic lesions (p = 0.008) and in glial tumors grade III than in non-neoplastic lesions (p = 0.001). The Cho/NAA ratio was significantly higher in glial tumors grade II than in non-neoplastic lesions (p = 0.037). AADC/ADC between glial tumors grade II and glial tumors grade III showed a statistical significance (p = 0.023). CONCLUSION Our study showed that 1H-MRS and apparent diffusion coefficients can help in evaluation and differentiation of solid brain lesions.