Tumor or not a tumor: Pitfalls and differential diagnosis in neuro-oncology.

The majority of intracranial expansive lesions are tumors. However, a wide range of lesions can mimic neoplastic pathology. Differentiating pseudotumoral lesions from brain tumors is crucial to patient management. This article describes the most common intracranial pseudotumors, with a focus on the imaging features that serve as clues to detect pseudotumors.

CT-guided infiltration of greater occipital nerve for refractory craniofacial pain syndromes other than occipital neuralgia.

PURPOSE: The purpose of this study was to evaluate the effectiveness of computed tomography (CT)-guided infiltration of greater occipital nerve (GON) for the treatment of refractory craniofacial pain syndromes other than occipital neuralgia. MATERIALS AND METHODS: Fifty-six patients suffering from refractory craniofacial pain syndromes were included between 2011 and 2017. There were 33 women and 23 men with a mean age of 50.7 years±13.1 (SD) (range: 27-74 years). CT-guided infiltration was performed at the intermediate site of the GON with local anesthetics and cortivazol. Twenty-six (26/56; 46%) patients suffered from chronic migraine, 14 (14/56; 25%) from trigeminal neuralgia and 16 (16/56; 29%) from cluster headaches. Clinical success at 1, 3, and 6 months was defined by a decrease of at least 50% of pain as assessed using visual analog scale (VAS). RESULTS: Mean overall VAS score before infiltration was 8.7±1.3 (SD) (range: 6 - 10). Mean overall VAS scores after infiltration were 2.3±3 (SD) (range: 0 - 10) (P<0.01) at one month, 3.5±3.3 (SD) (range: 0 - 10) (P<0.01) at three months and 7.6±1.3 (SD) (range: 1-10) (P<0.01) at six months. After infiltration, clinical success was achieved in 44 patients (44/56; 78.5%) at 1 month, 37 patients (37/56; 66%) at 3 months and 13 patients (13/56; 23%) at 6 months. Clinical success according to the clinical presentation were as follows: 88% (23/26) at one month, 73% (19/26) at 3 months, and 23% (6/26) at 6 months in patients with chronic migraine, 81% (13/16), 69% (11/16) and 31% (5/16) in those with cluster headaches and 57% (8/14), 50% (7/14) and 14% (2/14) in those with trigeminal neuralgia. No major complications due to CT-guided GON infiltration were reported in any patient. CONCLUSION: CT-guided infiltration at the intermediate site of the GON appears as an effective treatment of craniofacial pain syndromes especially in patients with chronic migraine and those with cluster headaches.

Diffusion MRI: literature review in salivary gland tumors.

Surgical resection is currently the best treatment for salivary gland tumors. A reliable magnetic resonance imaging mapping, encompassing tumor grade, location, and extension may assist safe and effective tumor resection and provide better information for patients regarding potential risks and morbidity after surgical intervention. However, direct examination of the tumor grade and extension using conventional morphological MRI remains difficult, often requiring contrast media injection and complex algorithms on perfusion imaging to estimate the degree of malignancy. In addition, contrast-enhanced MRI technique may be problematic due to the recently demonstrated gadolinium accumulation in the dentate nucleus of the cerebellum. Significant developments in magnetic resonance diffusion imaging, involving voxel-based quantitative analysis through the measurement of the apparent diffusion coefficient, have enhanced our knowledge on the different histopathological salivary tumor grades. Other diffusion imaging-derived techniques, including high-order tractography models, have recently demonstrated their usefulness in assessing the facial nerve location in parotid tumor context. All of these imaging techniques do not require contrast media injection. Our review starts by outlining the physical basis of diffusion imaging, before discussing findings from diagnostic studies testing its usefulness in assessing salivary glands tumors with diffusion MRI.

Is brain angio-MRI useful in infective endocarditis management?

In infective endocarditis (IE), brain magnetic resonance imaging (MRI) is helpful to diagnose clinically silent neurological events. We assessed the usefulness of systematic early brain MRI in IE diagnosis and medico-surgical management. Over a period of 1 year, all patients admitted in one of the three hospitals participating in and fulfilling the Duke criteria for definite or possible IE underwent cerebral MRI within 7 days of IE suspicion. Eight panels of experts analyzed the records a posteriori. For each case, one record with and one record without the MRI results were randomly assigned to two panels, which determined the theoretical diagnosis and treatment. Paired comparisons were performed using a symmetry test. Thirty-seven brain MRIs were performed within a median of 5 days after inclusion. MRI was pathological in 26 patients (70 %), showing 62 % microischemia and 58 % microbleeds. The expert advice did not differ significantly between the two evaluations (with or without the MRI results). The therapeutic strategies determined diverged in five cases (13.5 %). Diagnosis differed in two cases (5.4 %), with an upgrading of diagnosis from possible to definite IE using MRI results. Early brain MRI did not significantly affect the IE diagnosis and medico-surgical treatment plan. These results suggest that systematic use of early brain MRI is irrelevant in IE. Further studies are necessary to define whether MRI is mandatory in IE management within a multidisciplinary approach, with particular attention paid to better timing and the subset of patients in whom this imaging examination could be beneficial.

Value of brain MRI in infective endocarditis: a narrative literature review.

The nervous system is frequently involved in patients with infective endocarditis (IE). A systematic review of the literature was realized in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). This study sought to systematically evaluate the published evidence of the contribution of brain magnetic resonance imaging (MRI) in IE. The aim was to identify studies presenting the incidence and type of MRI brain lesions in IE. Fifteen relevant studies were isolated using the Medline, Embase, and Cochrane databases. Most of them were observational studies with a small number of patients. MRI studies demonstrated a wide variety and high frequency of cerebral lesions, around 80 % of which were mostly clinically occult. This review shows MRI's superiority compared to brain computed tomography (CT) for the diagnosis of neurologic complications. Recent developments of sensitive MRI sequences can detect microinfarction and cerebral microhemorrhages. However, the clinical significance of these microhemorrhages, also called cerebral microbleeds (CMBs), remains uncertain. Because some MRI neurological lesions are a distinctive IE feature, they can have a broader involvement in diagnosis and therapeutic decisions. Even if cerebral MRI offers new perspectives for better IE management, there is not enough scientific proof to recommend it in current guidelines. The literature remains incomplete regarding the impact of MRI on concerted decision-making. The long-term prognosis of CMBs has not been evaluated to date and requires further studies. Today, brain MRI can be used on a case-by-case basis based on a clinician's appraisal.

Fibromuscular dysplasia: what the radiologist should know: a pictorial review.

UNLABELLED: Fibromuscular dysplasia (FMD) is an idiopathic, segmentary, non-inflammatory and non-atherosclerotic disease that can affect all layers of both small- and medium-calibre arteries. The prevalence of FMD is estimated between 4 and 6 % in the renal arteries and between 0.3 and 3 % in the cervico-encephalic arteries. FMD most frequently affects the renal, carotid and vertebral arteries, but it can theoretically affect any artery. Radiologists play an important role in the diagnosis of FMD, and good knowledge of FMD's signs will certainly help reduce the delay between the first symptoms and diagnosis. The common string-of-beads aspect is well known, but less common presentations also have to be considered. These less common imaging findings include vascular loops, fusiform vascular ectasia, arterial dissection, aneurysm and subarachnoid haemorrhage. These radiologic presentations should be known by radiologists in order to diagnose possible FMD, particularly when present in young females or when associated with personal or familial hypertension, to reduce the delay between the onset of the first symptom and the final diagnosis. The patients have to be referred to specialised FMD centres for dedicated management. TEACHING POINTS: • Fibromuscular dysplasia is not a rare disease. • Radiologists should recognise less common presentations to orient specific management. • Vascular loops, fusiform vascular ectasia and a "string-of-beads" aspect are typical presentations. • Arterial dissection, aneurysm and subarachnoid haemorrhage are less typical radiologic presentations.