Value of Multimodal Imaging Approach to Diagnosis of Neurosarcoidosis

Abstract

Background: Neurosarcoidosis is a highly variable condition with many clinical and radiological manifestations, that can lead to difficult identification of isolated central nervous system (CNS) forms, because it could mimic inflammatory, infective or neoplastic disorders. Conventional magnetic resonance imaging (MRI) is gold standard to evaluate CNS involvement in neurosarcoidosis, despite the reported high sensitivity but low specificity in the diagnosis. Case presentation: Here, we describe a 52-year-old man that presented to our hospital with a 10-year history of focal seizures, progressive cognitive decline and motor impairment. Neurological examination revealed ataxic gait, bilateral telekinetic and postural tremor, brisk reflexes, left extensor plantar response and hypoesthesia to the right side of body. Brain 3T-magnetic resonance imaging (MRI) showed a leukoencephalopathy with multifocal nodular lesions hyperintense on T2/ fluid attenuated inversion recovery (FLAIR) weighted images involving basal ganglia, periventricular and deep white matter. The interpretation of this pattern on conventional MRI was unclear, opening a challenge on the differential diagnosis between inflammatory, infective or neoplastic disorders. Thus, to better understand the nature of these nodules, single-voxel 1H-magnetic resonance spectroscopy (1H-MRS), contrast enhanced computed tomography (CT) scan and fluorine-18-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET)/3T-MRI were performed. The parenchymal multifocal lesions exhibited slight N-acetyl-aspartate/creatine reduction without abnormal peaks on 1H-MRS, enhancement after the administration of contrast agent on CT and hypermetabolism on 18F-FDG-PET/3T-MRI. All these findings excluded primary neoplasms, metastasis, neurotuberculosis, neurocysticercosis and brain abscess, strongly suggesting a diagnosis of neurosarcoidosis. Therefore, a whole-body 18F-FDG-PET/CT was performed in order to identify subclinical extraneural sarcoidosis localizations, and a hypermetabolic nodule of the left lung upper lobe was found. Subsequently, a biopsy documented the presence of systemic sarcoidosis, supporting a diagnosis of probable neurosarcoidosis. Conclusions: This case demonstrated that a multimodal neuroimaging approach can provide different but complementary evidences to suspect sarcoidosis, especially in apparently CNS isolated forms.

Biomarkers in the Diagnosis and Prognosis of Sarcoidosis: Current Use and Future Prospects

“…However, 18 F-FDG PET can occasionally be helpful in demonstrating neurologic involvement not visualized on MRI (158). Furthermore, PET can help in detecting systemic manifestations of sarcoidosis other than neurological involvement (159) or assess disease activity during treatment of NS (160).…”

Neurosarcoidosis presenting as CRVO combined CRAO: a biopsy-proven case report of a Chinese patient

“…Although the treatment is very effective, but it might cover up the systemic symptoms of sarcoidosis. MRI features can be helpful to differentiate neurosarcoidosis from other diseases, such as meningioma, schwannomas, lymphomas, or metastatic conditions [12][13][14]. In our experience, the discrete features (like the optic and cranial nerves, spinal cord, leptomeninges, and dura mater), rather than a contiguous enhancement of the lesions, will be helpful for differential diagnosis.…”

Sarcoidosis: Updates on therapeutic drug trials and novel treatment approaches

“…A central premise of selection is establishing active sarcoidosis in the target organ(s) that will be sufficiently responsive to an efficacious treatment. This is accomplished in either or both of two major ways: (a) demonstration of inflammation consistent with sarcoidosis to the exclusion of other causes, which may be accomplished by positron emission tomography (PET)/computerized tomography (CT) scan in non-neurosarcoidosis, cardiac PET/cardiac magnetic resonance imaging (cMRI) in CS or brain MRI changes suggestive of edema/inflammation in neurosarcoidosis (97)(98)(99)(100)(101)(102) Additional challenges with patient recruitment include the need to promote diversity and ensure equitable enrollment of minorities and non-white participants. As much as is possible, trial populations should be reflective of the populations affected by the disease of interest.…”

“…A central premise of selection is establishing active sarcoidosis in the target organ(s) that will be sufficiently responsive to an efficacious treatment. This is accomplished in either or both of two major ways: (a) demonstration of inflammation consistent with sarcoidosis to the exclusion of other causes, which may be accomplished by positron emission tomography (PET)/computerized tomography (CT) scan in non-neurosarcoidosis, cardiac PET/cardiac magnetic resonance imaging (cMRI) in CS or brain MRI changes suggestive of edema/inflammation in neurosarcoidosis ( 97 – 102 ); (b) demonstration of clinically meaningful progressive disease in target organ(s) that is documented over a defined recent interval of time (for which other causes of worsening have been ruled out). Examples include worsening impairment or extent of disease on imaging, exercise tolerance or pulmonary function tests (PFTs) in lung involvement, worsening left ventricular ejection fraction (LVEF) on echocardiogram or cMRI in CS, or worsening limb strength or balance in CNS involvement.…”