B. Pasquier

Contribution of dynamic contrast MR imaging to the differentiation between dural metastasis and meningioma

PurposeTo determine the perfusion-sensitive characteristics of cerebral dural metastases and compare them with the data on meningiomas.MethodsTwenty-two patients presenting with dural tumor underwent conventional and dynamic susceptibility-contrast MR imaging: breast carcinoma metastases, two patients; colorectal carcinoma metastasis, one patient; lung carcinoma metastasis, one patient; Merkel carcinoma metastasis, one patient; lymphoma, one patient; meningiomas, 16 patients. The imaging characteristics were analyzed using conventional MR imaging. The cerebral blood volume (CBV) maps were obtained for each patient and the relative CBV (rCBV) in different areas was calculated using the ratio between the CBV in the pathological area (CBVp) and in the contralateral white matter (CBVn).ResultsThe differentiation between a meningioma and a dural metastasis can be difficult using conventional MR imaging. The rCBVs of lung carcinoma metastasis (1 case: 1.26), lymphoma (1 case: 1.29), breast carcinoma metastasis (2 cases: 1.50,1.56) and rectal carcinoma metastasis (1 case: 3.34) were significantly lower than that of meningiomas (16 cases: mean rCBV = 8.97±4.34, range 4–18). Merkel carcinoma metastasis (1 case: 7.56) showed an elevated rCBV, not different from that of meningiomas.ConclusionDural metastases are sometimes indistinguishable from meningiomas using conventional MR imaging. rCBV mapping can provide additional information by demonstrating a low rCBV which may suggest the diagnosis of metastasis.

Immunocytochemical investigation on dysplastic human tissue from epileptic patients

In this report we describe three patients with developmental cortical abnormalities (generally referred as cortical dysplasia), revealed by MRI and operated on for intractable epilepsy. Tissue, removed for strictly therapeutic reasons, was defined as the epileptogenic area by electroclinical data and stereo EEG (SEEG) recordings. Tissue samples were processed initially for histology, and selected sections were further processed for immunocytochemical investigation in order to determine whether the region of cortical dysplasia was co-extensive with the epileptogenic area. In two patients with nodular heterotopia, disorganized aggregates of neurons (as revealed by neuronal cytoskeletal markers) were found within the nodules. Both pyramidal and local circuit neurons were present in the nodules, but no reactive gliosis was present. When nodules reached the cortex, the cortical layers were disrupted. In the patient with localized cortical dysplasia, a complete disorganization of the cortical lamination was found, and numerous neurons were also present in the white matter. Disoriented pyramidal neurons weakly labelled with cytoskeletal neuronal markers were also present but no cytomegalic cells were found. One of the patients with nodular heterotopia underwent only partial resection of both the epileptogenic area and of the lesion; this patient still presents with seizures. The other patient with nodular heterotopia is seizure-free after a complete lesionectomy and excision of the epileptogenic area. The third patient, with focal cortical dysplasia, had two surgeries; she became seizure-free only after the excision of the epileptogenic area detected by SEEG recording. The present data suggest that the dysplastic areas identified by MRI should not be considered as the only place of origin of the ictal discharges. From the neuropathological point of view, the focal cortical dysplasia can be considered as a pure form of migrational disorder. However, the presence of large aggregates of neurons interspersed within the white matter, in the subcortical nodular heterotopia, suggests that a defect of neuronal migration could be associated with an exuberant production of neuroblasts and/or a disruption of mechanisms for naturally occurring cell death.

Dynamic contrast-enhanced MRI: differentiating melanoma and renal carcinoma metastases from high-grade astrocytomas and other metastases

Abstract. We performed conventional and dynamic susceptibility-contrast MRI imaging in 38xa0patients with brain tumours: 20 with metastases (breast carcinoma: two; renal carcinoma: five; colorectal carcinoma: one; lung carcinoma: seven; melanoma: five), and 18 with high-grade astrocytomas. We obtained cerebral blood volume (CBV) maps and calculated the relative CBV (rCBV) in different areas using the ratio between the CBV in the pathological area (CBVp) and in the contralateral white matter (CBVn). We calculated the maximum rCBV (rCBVmax) for each tumour and compared the mean rCBVmax in each group of tumours. The mean rCBV of melanoma metastases (5.35±2.32, range 3.14–9.23) and of renal carcinoma metastases (8.17±2.39, range 5.41–11.64) were significantly greater than those of high-grade astrocytomas (2.61±1.17, range 1.3—5.0) (P=0.002 and <0.001, respectively) and of lung carcinoma metastases (2.94±0.86, range 1.43–4.04) (P=0.003 and 0.002). There was no statistically significant difference between the mean rCBV of lung metastases and of high-grade astrocytomas (P=0.59). Large, solitary, necrotic metastases can be indistinguishable from high-grade astrocytomas using conventional MRI. Demonstration of an elevated rCBV which may suggest a hypervascular lesion such as renal carcinoma or melanoma.

Chordoid glioma of the third ventricle: CT and MRI, including perfusion data.

Abstract. Chordoid glioma is a homogeneous tumour involving the third ventricular region of middle-aged women, containing a small central cyst or necrosis. Histologically the tumour has a chordoid appearance. We report a new case with a haemodynamic imaging approach which indicates tumour angiogenesis at the capillary level.

Intérêt de l’imagerie de perfusion dans l’étude des astrocytomes pilocytiques et des hémangioblastomes : étude préliminaire

PURPOSEnPilocytic astrocytomas (PA) and hemangioblastomas (HB) can present the same morphological characteristics on conventional MRI sequences, most usually in the form of a cerebellar cystic mass with a mural nodule that strongly enhances on post-contrast T1 images. We discuss here the value of perfusion MRI in the differentiation of these two tumors, the diagnoses of which have already been histopathologically established.nnnMETHODnEleven patients with PA and eight with HB underwent first-pass perfusion MRI. The maximum relative cerebral blood volume (rCBV(max)), defined as the ratio between the CBV(max) in tumor tissue and the CBV in healthy, contralateral white matter, is considered to be indicative of the type of tumor.nnnRESULTSnThe difference between the rCBV(max) of PA (rCBV(max)=1.19+/-0.71, range 0.6-3.27) compared with that of HB (rCBV(max)=9.37+/-2.37, range 5.38-13) was significant (P<0.001). The first-pass curve crossed the baseline, corresponding to vascular permeability problems in both PA and HB.nnnCONCLUSIONnThe first-pass method of perfusion MRI is a quick and useful way to differentiate between PA and HB.

Pseudotumoral brain lesion as the presenting feature of sarcoidosis

Sarcoidosis rarely presents as an intracranial mass lesion. We report the case of a patient presenting a disturbance of cognitive functions in whom CT and MRI demonstrated a large right fronto-temporal mass lesion with contrast enhancement and surrounding marked oedema, highly suggestive of a brain tumour. The diagnosis of neurosarcoidosis was made after stereotactic biopsy of the lesion.

Bcl‐2 expression in a papillary tumor of the pineal region

Neuroepithelial papillary tumor of the pineal region (PTPR) has been described by several groups and recognized by the 2007 World Health Organization Classification of Tumors of the Central Nervous System. The proto‐oncogen Blc‐2 can function as an apoptosis suppressor and can promote neoplastic transformation. It may also be involved in neuroendocrine differentiation in some tumors. As PTPRs express neuroendocrine markers, we investigated the expression of Bcl‐2 in tumoral cells of a new case of PTPR in a 42‐year‐old woman. Bcl‐2 immunostaining was detected in the cytoplasm of the tumoral cells; staining intensity was heterogeneous from cell to cell and more intense in papillary areas. This intense expression of Bcl‐2 in one case of PTPR with a high proliferation index (8%) might be related to the malignancy of this neoplasm. It will be interesting to investigate the prognosis impact of Bcl‐2 expression in a large series of PTPRs.

Tumor arising in the periventricular region

A 32-year-old immunocompetent female patient, 8 months pregnant, underwent three complex partial seizures beginning with visual hallucinations and secondarily generalized. She had been in good health until then. The pregnancy was normal and no high blood pressure was noted. Clinical examination revealed a left nystagmus, a right sensory hemibody deficiency and a right pyramidal syndrome. MRI showed an isolated intraparenchymal lesion in the left parieto-occipital region with an enhancement of the left lateral ventricle floor (Fig. 1a,b). The biological assessments, including hemogram, ionogram, CRP, liver enzymes and b2 microglobulin, were all normal. An elevated erythrocyte sedimentation rate was noted. CMV, HBV, HCV, and Lyme serologies were negative. Previous HSV, EBV, and varicella zoster virus infection markers were found. CSF examination revealed hyperproteinorachia (0.95 g/L) without cellular reaction. No tumoral cells were found. Thoracic and abdominal CT was normal. After the brain biopsy, a course of corticosteroids was started. The patient did not present with any other seizures. Five years after the first epileptic manifestations, follow-up MRI demonstrated resolution of the enhancing lesions (Fig. 2) and the patient was in good health with 10 mg of corticosteroids daily.

Case report: Magnetic resonance imaging in Lhermitte-Duclos disease

A case of Lhermitte-Duclos disease is reported. Characterized by architectural disruption of the cerebellar folia with disorganization of the normal three layers, the lesion is easily identified using magnetic resonance imaging.

Spectroscopie 1H, perfusion, diffusion: quelle place pour ces techniques lors du diagnostic et du suivi des principales tumeurs cérébrales sus-tentorielles de l'adulte ?

Resume Introduction En quelques annees, l’IRM a evolue d’une exploration morphologique vers une exploration metabolique et fonctionnelle. Etat des connaissances L’IRM est la pierre angulaire du bilan des tumeurs cerebrales. Elle a un role lors du bilan initial et permet souvent une bonne caracterisation tissulaire du processus lesionnel. Toutefois, elle ne suffit pas a differencier abces, gliome malin et metastase unique, a apprecier le grade histologique des gliomes, a definir les limites tumorales, a caracteriser les tumeurs meningees. Elle a un role lors du suivi pour controler le geste operatoire, apprecier la reponse au traitement, rechercher des signes de recidive. Neanmoins, l’interpretation ne repose que sur des donnees volumetriques qui peuvent etre prises en defaut. Perspectives La spectroscopie 1 H, la diffusion et la perfusion, techniques disponibles sur la plupart des appareils cliniques apportent des informations complementaires sur le metabolisme et la vascularisation des tumeurs. Elles permettent une meilleure caracterisation tissulaire et une meilleure comprehension des modifications post-therapeutiques. Actuellement, aux donnees morphologiques du bilan IRM d’une tumeur cerebrale doivent s’ajouter des informations metaboliques et fonctionnelles.