Sphenoid Sinus Epidermoid Cyst

We present an unusual case of an epidermoid cyst in the sphenoid sinus with extensive bony erosions and mass effect, compressing the optic nerve causing visual disturbances. Epidermoid cysts of the paranasal sinuses are extremely rare cases. They usually present as intradural, extraaxial, benign masses of the cerebellopontine angle but they should also be considered in the differential diagnosis of sphenoid sinus lesions. The typical imaging appearance of craniocerebral epidermoid cysts is demonstrated and pathophysiological considerations of formation in the paranasal sinuses are discusse

Changes of non‐affected upper limb cortical representation in paraplegic patients as assessed by fMRI

Peripheral and central nervous system lesions can induce reorganization within central somatosensory and motor body representations. We report changes in brain activation patterns during movements of non‐affected body parts in paraplegic patients with spinal cord injury (SCI). Nine SCI patients and 12 healthy controls underwent blood oxygen level dependent signal functional MRI during sequential finger‐to‐thumb opposition, flexion and extension of wrist and of elbow, and horizontal movements of the tongue. Single subject and group analyses were performed, and the activation volumes, maximum t values and centres of gravity were calculated. The somatotopical upper limb and tongue representations in the contralateral primary motor cortex (M1) in the SCI patients were preserved without any shift of activation towards the deefferented and deafferented M1 foot area. During finger movements, however, the SCI patients showed an increased volume in M1 activation. Increased activation was also found in non‐primary motor and parietal areas, as well as in the cerebellum during movements of the fingers, wrist and elbow, whereas no changes were present during tongue movements. These results document that, in paraplegic patients, the representation of the non‐impaired upper limb muscles is modified, though without any topographical reorganization in M1. The extensive changes in primary and non‐primary motor areas, and in subcortical regions demonstrate that even distant neuronal damage has impact upon the activation of the whole sensorimotor syste

What Disconnection Tells about Motor Imagery: Evidence from Paraplegic Patients

Brain activation during motor imagery has been the subject of a large number of studies in healthy subjects, leading to divergent interpretations with respect to the role of descending pathways and kinesthetic feedback on the mental rehearsal of movements. We investigated patients with complete spinal cord injury (SCI) to find out how the complete disruption of motor efferents and sensory afferents influences brain activation during motor imagery of the disconnected feet. Eight SCI patients underwent behavioral assessment and functional magnetic resonance imaging. When compared to a healthy population, stronger activity was detected in primary and all non-primary motor cortical areas and subcortical regions. In paraplegic patients the primary motor cortex was consistently activated, even to the same degree as during movement execution in the controls. Motor imagery in SCI patients activated in parallel both the motor execution and motor imagery networks of healthy subjects. In paraplegics the extent of activation in the primary motor cortex and in mesial non-primary motor areas was significantly correlated with the vividness of movement imagery, as assessed by an interview. The present findings provide new insights on the neuroanatomy of motor imagery and the possible role of kinesthetic feedback in the suppression of cortical motor output required during covert movement

Brainstem cavernoma surgery with the support of pre- and postoperative diffusion tensor imaging: initial experiences and clinical course of 23 patients

The spatial complexity of highly vulnerable structures makes surgical resection of brainstem cavernomas (BSC) a challenging procedure. Diffusion tensor imaging (DTI) allows for the visualization of white matter tracts and enables a better understanding of the anatomical location of corticospinal and sensory tracts before and after surgery.We investigated the feasibility and clinical usefulness of DTI-based fiber tractography in patients with BSC.Pre- and postoperative DTI visualization of corticospinal and sensory tracts were retrospectively analyzed in 23 individuals with BSC. Preoperative and postoperative DTI-fiber accuracy were associated to the neurological findings. Preoperatively, the corticospinal tracts were visualized in 90 % of the cases and the sensory tracts were visualized in 74 % of the cases. Postoperatively, the corticospinal tracts were visualized in 97 % of the cases and the sensory tracts could be visualized in 80 % of the cases. In all cases, the BSC had caused displacement, thinning, or interruption of the fiber tracts to various degrees. Tract visualization was associated with pre- and postoperative neurological findings. Postoperative damage of the corticospinal tracts was observed in two patients. On follow-up, the Patzold Rating (PR) improved in 19 out of 23 patients (83 %, p = 0.0002).This study confirms that DTI tractography allows accurate and detailed white matter tract visualization in the brainstem, even when an intraaxial lesion affects this structure. Furthermore, visualizing the tracts adjacent to the lesion adds to our understanding of the distorted intrinsic brainstem anatomy and it may assists in planning the surgical approach in specific cases

Dandy–Walker syndrome

DANDY–WALKER SYNDROME (DWS) is a congenital malformation of neural tube closure characterized by a localized defect in the differentiation of the hindbrain and it consists of three major abnormalities: (i) complete or partial agenesis of the cerebellar vermis (mainly its inferior portion); (ii) posterior fossa cyst (strictly speaking, a cystic dilatation of the fourth ventricle); and (iii) an enlarged posterior fossa with upward displacement of the tentorium, lateral sinuses, and torcular (Table 1). The triad is commonly associated with hydrocephalus, but this condition should be considered a very common complication (occurring in more than 80% of cases) and not part of the malformation

Natalizumab-related progressive multifocal leukoencephalopathy-immune reconstitution inflammatory syndrome: a case report highlighting clinical and mrI features

Multiple sclerosis (MS) patients treated with natalizumab often face the uncommon but severe complication of developing progressive multifocal leukoencephalopathy (PML). PML may be further complicated by immune reconstitution inflammatory syndrome (IRIS) after the removal of the drug. Since both PML and IRIS are associated with high morbidity and mortality rates, early clinical and radiological diagnosis of these complications is of paramount importance. Here, we report a case of an adult male patient who was diagnosed with PML after receiving natalizumab therapy for 6 years for the treatment of MS. Upon cessation of natalizumab, he presented with a paradoxical worsening of clinical and radiological findings consistent with an inflammatory brain injury due to IRIS. He was treated with high dose corticosteroid therapy followed by a gradual improvement in clinical and imaging findings. This article illustrates the magnetic resonance imaging (MRI) features of natalizumab-associated PML-IRIS, along with a brief overview of its clinical features, complications and management strategies

Imaging of adult brainstem gliomas

Brainstem gliomas (BSGs) are uncommon in adults accounting for about 2% of all intracranial neoplasms. They are often phenotypically low-grade as compared to their more common paediatric counterparts. Since brainstem biopsies are rarely performed, these tumours are commonly classified according to their MR imaging characteristics into 4 subgroups (a) diffuse intrinsic low-grade gliomas, (b) enhancing malignant gliomas, (c) focal tectal gliomas and (d) exophytic gliomas/other subtypes. The prognosis and treatment is variable for the different types and is almost similar to adult supratentorial gliomas. Radiotherapy (RT) with adjuvant chemotherapy is the standard treatment of diffuse low-grade and malignant BSGs, whereas, surgical resection is limited to the exophytic subtypes. Review of previous literature shows that the detailed imaging of adult BSGs has not received significant attention. This review illustrates in detail the imaging features of adult BSGs using conventional and advanced MR techniques like diffusion weighted imaging (DWI), diffusion tensor imaging (DTI), MR perfusion weighted imaging (PWI), MR spectroscopy (MRS), as well as 18 F-fluoro-ethyl-tyrosine positron emission tomography (18F-FET/PET). We have discussed the pertinent differences between childhood and adult BSGs, imaging mimics, prognostic factors and briefly reviewed the treatment options of these tumours

Aggressive primary olfactory neuroblastoma of the sphenoclival region: A case report and literature review

Olfactory neuroblastoma (ONB) is an uncommon malignant tumor of neural crest origin, which commonly arises in the superior nasal cavity. Ectopic origin of an ONB is exceedingly rare. We describe a rare case of an ectopic sphenoclival ONB with extensive involvement of the central skull base and with development of systemic metastases. To our knowledge, ours is the first case that describes the imaging features of this rare entity on computed tomography (CT), magnetic resonance imaging, 18 F-fluorodeoxyglucose-positron-emission tomography/CT, and digital subtraction angiography. We also describe the histological features, imaging differentials, and treatment options for this tumor along with a brief literature review