Endoscopic resection of intracranial dermoid cysts.

INTRODUCTION: Nasal dermoid cysts are congenital lesions which are often diagnosed in infancy or childhood. However, a small number present in adulthood, and some extend intracranially. Traditional treatment for the intracranial portion of these cysts includes frontal craniotomy. CASE REPORTS: Two intracranial dermoid cysts were resected via a transnasal endoscopic approach, using 70° nasal endoscopy for complete visualisation and intracranial tumour removal. We describe our technique for the procedure itself and for reconstruction of the skull base defect. DISCUSSION AND CONCLUSION: The endoscopic transnasal skull base approach is an excellent alternative to a traditional frontal craniotomy, to achieve complete resection of intracranial dermoid cysts.

Imaging manifestations of progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease caused by reactivation of JC virus in immunosuppressed patients. The diagnosis is usually suggested on imaging and confirmed by cerebrospinal fluid polymerase chain reaction (PCR) for JC virus DNA. In this article, we review the imaging manifestations of PML on computed tomography (CT), magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), MR spectroscopy, single photon-emission computed tomography (SPECT) and positron-emission tomography (PET), and outline the role of imaging in follow-up and prognostication.

JC virus infection of the brain.

Since its initial description, there have been significant changes in the epidemiology, pathogenesis, and clinical and imaging manifestations of JCV infection of brain. The most common clinical manifestation is PML. Other recently described CNS manifestations are JCE, JCVGCN, and JCM. Although AIDS is the most common predisposing factor for JCV reactivation, there is increasing incidence of brain manifestations of JCV reactivation in non-HIV settings, including different rheumatologic, hematologic, and oncologic conditions; monoclonal antibody therapy; transplant recipients; primary immunodeficiency syndromes; and even in patients without any recognizable immune deficiency. IRIS may develop secondary to restoration of immunity in HIV-positive patients with PML receiving antiretroviral therapy. This is of profound clinical significance and needs to be diagnosed promptly. Imaging plays a crucial role in the diagnosis of the disease, monitoring of treatment response, identifying disease progression, and predicting prognosis. In this article, current understanding of the epidemiology, pathogenesis, clinical presentations, and all aspects of imaging of JCV infection of the brain have been comprehensively reviewed.

Diffusion tensor imaging in hypertrophic olivary degeneration.

SUMMARY: We report DTI and fiber tractography findings in a case of hypertrophic olivary degeneration. A 51-year-old man presented with an abnormal gait and visual difficulties. MR imaging showed enlargement of the right medullary olive and a vascular lesion in the right pontine tegmentum. Fiber tractography showed decreased volume of the right central tegmental tract, supporting a diagnosis of HOD.

A compartment-based approach for the imaging evaluation of tinnitus.

Tinnitus affects 10% of the US general population and is a common indication for imaging studies. We describe a sequential compartment-based diagnostic approach, which simplifies the interpretation of imaging studies in patients with tinnitus. The choice of the initial imaging technique depends on the type of tinnitus, associated symptoms, and examination findings. Familiarity with the pathophysiologic mechanisms of tinnitus and the imaging findings is a prerequisite for a tailored diagnostic approach by the radiologist.

Correlation of MR imaging findings and clinical manifestations in neurosarcoidosis.

BACKGROUND AND PURPOSE: MR imaging is widely used for the diagnosis and follow-up of neurosarcoidosis lesions. However, the temporal evolution of imaging abnormalities and the prognostic significance of imaging features is not well understood. We undertook a retrospective study of patients with biopsy-proved or clinically diagnosed neurosarcoidosis for the following reasons: 1) to assess concordance between abnormalities noted on MR imaging with neurologic symptoms at presentation; 2) to correlate changes in imaging findings during follow-up with clinical improvement or worsening; and 3) to identify imaging features that may have prognostic significance. MATERIALS AND METHODS: We reviewed radiologic records from 1999 to 2008 of patients with biopsy-proved or clinically diagnosed neurosarcoidosis and correlated MR imaging findings in these patients with their demographic characteristics, clinical features, and symptomatic responses during follow-up. RESULTS: Thirty-two patients were included in the study. Cranial nerve lesions and leptomeningeal disease identified on MR imaging were symptomatic in 64% patients, dural lesions were associated with symptoms in 28% patients, but nonenhancing white matter lesions did not have correlating symptoms. During follow-up, MR imaging findings generally changed in concordance with the change in clinical symptoms (80% patients). Cranial nerve enhancement (9/11) and spinal lesions (5/8) were most likely to resolve with clinical improvement, whereas dural lesions (6/11), enhancing parenchymal lesions (3/7), and non-enhancing parenchymal lesions (0/4) were less likely to change during therapy. Patients with > or =1 enhancing T2-hypointense lesion (4/7, 57%) were less likely to show clinical improvement than those without such lesions (12/13, 92%). CONCLUSIONS: Although many sarcoid-related MR imaging abnormalities were not associated with correlating symptoms at presentation, there was a high degree of concordance between changes in clinical symptoms and MR imaging abnormalities during follow-up. Enhancing T2-hypointense dural and parenchymal lesions were associated with suboptimal imaging and clinical response to immunosuppressive therapy.

CT imaging of head and neck lupus panniculitis.

Lupus panniculitis (LP) or lupus erythematosus profundus (LEP) is a lupus-associated dermatologic condition predominantly affecting young to middle-aged women in which the deep dermis and subcutaneous fat are mainly involved. The lesions are usually located on the forehead, cheeks, proximal aspect of the limbs, and buttocks, though cases have occasionally been reported with orbital, breast, and salivary gland involvement. Descriptions of imaging findings of LP are very scarce in the literature. We describe the CT scan imaging features of the case of a patient with head and neck LP.

Cervical spinal cord compression and the Hoffmann sign.

Little information exists about the ability of the Hoffmann sign to predict cervical spinal cord compression. The objective of this study was to determine the correlation between the Hoffmann sign and cervical spinal cord compression in a consecutive series of patients seen by a single spine surgeon. All new patients with complaints related to their cervical spine were included. Hoffmann sign was elicited by flicking the nail of the middle finger. Any flexion of the ipsilateral thumb and/or index finger was considered positive. All imaging studies were reviewed for spinal cord compression. Cord compression was defined as flattening of the AP diameter of the spinal cord coexisting with obliteration of CSF around the cord compared to normal levels. Of 165 patients, 124 patients had imaging of their spinal canal. Review by the spine surgeon found sensitivity of the Hoffmann sign relative to cord compression was 58%, specificity 78%, positive predictive value 62%, negative predictive value 75%. 49 studies were also read by a "blinded" neuroradiologist, the sensitivity was 33%, specificity 59%, positive predictive value, 26%, negative predictive value 67%. Although attractive as a simple method of screening for cervical spinal cord compression, the Hoffmann sign, in the absence of other clinical findings, is not in our experience a reliable test.

Imaging of vascular lesions of the head and neck.

The imaging armamentarium for imaging head and neck vascular lesions and the imaging features of each have been reviewed. Imaging is an indispensable part of the diagnosis and treatment planning of these lesions. The architecture and vascularity of these lesions are keys to their correct diagnosis. High-flow lesions (AVMs and hemangiomas) can be distinguished readily from low-flow lesions (venous malformations and lymphatic malformations) with these techniques, without the need for conventional angiography in the majority of cases. More-over, the architecture of the lesions depicted on imaging studies can lead to a reasonably specific diagnosis. MR imaging is the best tool for this assessment, but complementary information from ultrasound or CT can help arrive at the correct diagnosis when the results of MR imaging are equivocal. Ultrasound can correctly characterize the lesion as high flow or low flow but is limited in its ability to determine the full extent of the lesion. The usefulness of CT is more limited. Application of newer CT techniques (multidetector helical CT with image reconstruction) may increase the role of CT in high-flow lesions, but the greater soft tissue contrast sensitivity of MR imaging remains its strong suit. Conventional angiography is usually reserved for pretherapeutic evaluation.

Lovastatin therapy for X-linked adrenoleukodystrophy: clinical and biochemical observations on 12 patients.

X-linked adrenoleukodystrophy (X-ALD) is a progressive demyelinating disorder whose neurological signs and symptoms can manifest in childhood as cerebral ALD or in adulthood in the form of a progressive myelopathy (AMN). The consistent metabolic abnormality in all forms of X-ALD is an inherited defect in the peroxisomal beta-oxidation of very long chain (VLC) fatty acids (>C(22:0)) which may in turn lead to a neuroinflammatory process associated with demyelination of the cerebral white matter. The current treatment for X-ALD with Lorenzo's oil aims to lower the excessive quantities of VLC fatty acids that accumulate in the patients' plasma and tissues, but does not directly address the inflammatory process in X-ALD. We have previously demonstrated that lovastatin and other 3-HMG-CoA reductase inhibitors are capable of normalizing VLC fatty acid levels in primary skin fibroblasts derived from X-ALD patients. Lovastatin can block the induction of inducible nitric oxide synthase and proinflammatory cytokines in astrocytes, microglia, and macrophages in vitro. In a preliminary report, we demonstrated that lovastatin therapy can normalize VLC fatty acids in the plasma of patients with X-ALD. Here we report our clinical and biochemical observations on 12 patients with X-ALD who were treated with lovastatin for up to 12 months. Our results show that the high plasma levels of hexacosanoic acid (C(26:0)) showed a decline from pretreatment values within 1 to 3 months of starting therapy with 40 mg of lovastatin per day and stabilized at various levels during a period of observation up to 12 months. The percentage decline from pretreatment values varied and did not correlate with the type of ALD gene mutation (point mutation versus gene deletion). In 6 patients, in whom red cell membrane fatty acid composition was studied, a mean correction of 50% of the excess C(26:0) was observed after 6 months of therapy suggesting sustained benefit. In a few patients who discontinued lovastatin therapy plasma C(26:0) levels reverted to pretreatment values suggesting a cause and effect relationship between these events. Two patients dropped out of the study claiming no clinical benefit, 1 was withdrawn due to adverse effects, and an adult patient with cerebral involvement died during the study. A 10-year-old boy with severe cerebral involvement showed worsening of his neurological status. All patients with AMN remained neurologically stable or showed modest subjective improvement. All patients who did not have Addison's disease at the time of enrollment maintained normal adrenal function throughout the study. The implications of our findings for developing an effective therapy for X-ALD are discussed.

Cranial MR imaging of osteopetrosis.

BACKGROUND AND PURPOSE: The purpose of this study was to describe the cranial MR imaging manifestations of osteopetrosis. These features have not previously been reported in the literature. METHODS: Cranial MR studies, obtained with a uniform imaging protocol, were reviewed in 47 patients with osteopetrosis. Thirty-four patients had autosomal recessive (malignant) osteopetrosis (AROP), seven had intermediate osteopetrosis (IOP), and six had either type I or type II autosomal dominant osteopetrosis (ADOP I or II). The prevalence of abnormalities was tabulated and compared with the specific osteopetrosis variants. RESULTS: All patients with osteopetrosis had thickening and sclerosis of the calvaria. Ventriculomegaly, tonsillar herniation, proptosis, and dural venous sinus stenosis were observed in the majority of patients with AROP and ADOP I. Optic nerve sheath dilatation occurred in many of the patients with AROP and in all patients with ADOP I. Acquired cephaloceles were also observed only in these two groups. Optic nerve atrophy and optic canal stenosis were observed in a majority of patients with AROP, IOP, and ADOP II. Middle ear fluid was prevalent in AROP and IOP, present in over half the patients in each group. Features seen most prevalently, or exclusively, in AROP included stenosis of the internal carotid and vertebral arteries and extramedullary hematopoiesis. CONCLUSION: The cranial MR imaging features of osteopetrosis are both shared and unique among the various subtypes of the disease. The specific cranial and intracranial manifestations reflect the predominant calvarial or skull base patterns of bone thickening. The unique features seen in patients with AROP probably reflect the early age of onset and the greater severity of this form of the disease.

Cystlike white matter lesions in tuberous sclerosis.

PURPOSE: To investigate the presence of small cystlike structures in the cerebral hemispheric white matter on MR images of patients with tuberous sclerosis. METHODS: The MR images of 18 consecutive patients with tuberous sclerosis were reviewed retrospectively. RESULTS: Eight of the 18 patients were found to have cystlike structures in the cerebral white matter. The signal intensity of these lesions was isointense with cerebrospinal fluid on T1-, proton density-, and T2-weighted images. Four patients were imaged with a fluid-attenuated inversion recovery sequence, which in each case also showed fluid-type signal in these areas. Three of the patients had CT for correlation, and these scans supported the diagnosis of cystic lesions. Cysts ranged in number from one to 12 per patient and were usually smaller than 1 cm. The most common location was adjacent to the occipital horn or trigone of the lateral ventricle (six of eight patients). Less frequent sites were near the frontal horns, in the corpus callosum, and in the deep white matter near the body of the lateral ventricle. Cysts in five patients were either immediately adjacent to a cortical tuber or in the center of a white matter dysplastic lesion. A cyst in one patient had septa, and none of the cysts enhanced. CONCLUSIONS: Cystlike structures in the cerebral hemispheric white matter were seen on the MR images of 44% of 18 patients with tuberous sclerosis. Whether these findings represent cystic degeneration of dysplastic tissue or are unrelated to the disease process of tuberous sclerosis is unknown. More than one pathogenesis may exist.

Paraplegia due to ossification of ligamenta flava in X-linked hypophosphatemia. A case report.

STUDY DESIGN: Spinal canal decompression at the most prominent of multiple posterior calcified thoracic lesions in a case of X-linked hypophosphatemia was undertaken for treatment and diagnosis purposes, as well as to assess possible nature of the pathophysiology underlying the presenting deficits. OBJECTIVES: To discuss the clinical assessment diagnostic and treatment aspects of this rare coincidence of ossification of ligamenta flava in the patient with the skeletal deformities of X-linked hypophosphatemia. SUMMARY OF BACKGROUND DATA: The patient with the stigmata and chemical findings of an X-linked hypophosphatemia presented with paraplegia and multiple calcified posterior spinal thoracic lesions. This was studied with magnetic resonance imaging and electrophysiologic studies of the spinal sensory pathways of the legs. These data constituted the preoperative information required to assess later results of surgical intervention. METHODS: Presurgical clinical, imaging and electrophysiologic studies and laboratory and pathologic investigations of the surgical specimens. RESULTS: Resolution of the paraplegia with walking and return to work in a physically demanding job for the last 4 or 5 years of postoperative follow-up after surgical decompression of the spinal cord only at the worst and highest of the effected spinal levels. CONCLUSION: The coincidence of X-linked hypophosphatemia and ossification of ligamenta flava has been reported only in two or three cases in the literature. Removal of the offending ossifying lesion is known to result in resolution of the clinical deficits but similar lesions at other spinal levels are suspected of producing recurrences. The return of function and of the corresponding electrophysiologic correlates indicate a neurono-apractic nature of the neurologic symptoms.

Developmental neural abnormalities and seizures in epidermal nevus syndrome.

The epidermal nevus syndrome (ENS) is an unusual neurocutaneous disorder consisting of the combination of an epidermal nevus and a central nervous system (CNS), ophthalmological, and/or skeletal abnormality. The study reports four new patients with ENS. Each had a confirmatory biopsy of the epidermal nevus, abnormal neurological examination findings, and documented CNS anatomical studies by imaging or autopsy. The paper also reviews the literature in English to determine neurological abnormalities found in skin-biopsy-proven cases of ENS. Hemi-atrophy, hemimegalencephaly, migrational abnormalities and vascular anomalies were found to be the most frequent intracranial abnormalities associated with ENS. Seizures and/or disabling moderate to severe developmental delays were present in a majority of patients. Seizure onset during the neonatal period or early infancy was associated with major hemispheric malformations. Neuroectodermal-derived ocular lesions were often bilateral. No consistent relation between laterality of the nevus and laterality of CNS abnormalities was found, supporting the gene mosaicism theory of pathogenesis.

Petrous carotid canal stenosis in malignant osteopetrosis: CT documentation with MR angiographic correlation.

PURPOSE: To study the association between petrous carotid canal (PCC) and internal carotid artery (ICA) stenoses in patients with malignant osteopetrosis. MATERIALS AND METHODS: Mean and minimum PCC diameters obtained from cranial computed tomographic (CT) scans in 20 patients were compared with similar measurements in 52 control subjects. ICA caliber, evaluated with magnetic resonance (MR) arteriography, was correlated with age and PCC dimensions. RESULTS: There was a statistically significant difference between patient and control PCC diameters. There was a strong positive correlation between age and PCC diameter in the control subjects, but only a weakly positive correlation in the patients. One or both ICAs were stenotic on all patient MR arteriograms. MR angiographic stenosis grade correlated positively with age but not with PCC diameters. CONCLUSION: PCC and ICA stenoses occur frequently in patients with malignant osteopetrosis. Bony overgrowth or a "persistent fetal state" may produce the PPC stenoses. The findings do not support progressive PCC narrowing in these patients.

MR of nasolabial cysts.

We report the MR imaging findings in two cases of nasolabial cysts. Demonstration of their extraosseous location with cross-sectional imaging should prevent confusion with maxillary cysts and obviate unwarranted dental or maxillary surgery.