Adult Age Differences in Self-Reported Pain and Anterior CSF Space in Chiari Malformation.

Chiari malformation type I (CMI) is a neural disorder with sensory, cognitive, and motor defects, as well as headaches. Radiologically, the cerebellar tonsils extend below the foramen magnum. To date, the relationships among adult age, brain morphometry, surgical status, and symptom severity in CMI are unknown. The objective of this study was to better understand the relationships among these variables using causal modeling techniques. Adult CMI patients (80% female) who either had (n = 150) or had not (n = 151) undergone posterior fossa decompression surgery were assessed using morphometric measures derived from magnetic resonance images (MRI). MRI-based morphometry showed that the area of the CSF pocket anterior to the cervico-medullary junction (anterior CSF space) correlated with age at the time of MRI (r = - .21). Also, self-reported pain increased with age (r = .11) and decreased with anterior CSF space (r = - .18). Age differences in self-reported pain were mediated by anterior CSF space in the cervical spine area-and this effect was particularly salient for non-decompressed CMI patients. As CMI patients age, the anterior CSF space decreases, and this is associated with increased pain-especially for non-decompressed CMI patients. It is recommended that further consideration of age-related decreases in anterior CSF space in CMI patients be given in future research.

Advanced CT and MR Imaging of the Posttreatment Head and Neck.

Advances in MR and computed tomography (CT) techniques have resulted in greater fidelity in the assessment of treatment response and residual tumor on one hand and the assessment of recurrent head and neck malignancies on the other hand. The advances in MR techniques primarily are related to diffusion and perfusion imaging which rely on the intrinsic architecture of the tissues and organ systems. The techniques exploit the density of the cellular architecture; and the vascularity of benign and malignant lesions which in turn affect the changes in the passage of contrast through the vascular bed. Dual-energy CT and CT perfusion are the major advances in CT techniques that have found significant applications in the assessment of treatment response and tumor recurrence.

Quantification of Cerebellar Crowding in Type I Chiari Malformation.

This study was focused on a semi-automated morphometric analysis of the cerebellum in the mid-sagittal plane as an alternative to tonsillar descent alone in the evaluation of Chiari malformation type 1 (CMI) patients. Morphometric analyses of posterior fossa structures were performed on mid-sagittal MRI images of 375 individuals (females, > 18 years, 235 CMI and 140 healthy controls). Twenty-six parameters including linear, angular and area measurements together with non-dimensional ratios were calculated. Eighteen parameters were found to be significantly different between CMI and control subjects. Smaller posterior cranial fossa (PCF) area in CMI subjects was attributed to a smaller PCF area anterior to the brainstem. The cerebellar area was found to be larger in CMI subjects as compared to controls (15.1%), even without inclusion of the tonsillar area below the foramen magnum (FM) (8.4%). The larger cerebellar area in CMI subjects was due to cranial-caudal elongation of the cerebellum, predominately below the fastigium. The cerebrospinal fluid spaces below the FM were smaller in CMI subjects as compared to controls. Overall, greater cerebellar crowding was identified in CMI subjects relative to healthy controls. These observations may improve our understanding of the pathophysiology of CMI in adult female patients.

Cerebrospinal fluid velocity amplitudes within the cerebral aqueduct in healthy children and patients with Chiari I malformation.

PURPOSE: To assess the effects of cerebrospinal fluid (CSF) bidirectional motion in Chiari malformation type I (CMI), we monitored CSF velocity amplitudes on phase contrast MRI (PC-MRI) in patients before and after surgery; and in healthy volunteers. MATERIALS AND METHODS: 10 pediatric volunteers and 10 CMI patients participated in this study. CMI patients underwent PC-MRI scans before and approximately 14 months following surgery. Two parameters-amplitude of mean velocity (AMV) and amplitude of peak velocity (APV) of CSF-were derived from the data. Measurements were made at the mid-portion of the cerebral aqueduct, and anterior and posterior compartments of the spinal canal at the craniovertebral junction (CVJ). RESULTS: AMV and APV within the cerebral aqueduct were greater in preoperative assessments of the CMI patients compared to normal volunteers. Statistical significance was noted when comparing aqueductal AMV between the preoperative values and normal controls (P = 0.03), and before and after surgery in the CMI patients (P = 0.02). Lower values of AMV (P = 0.02) were noted in the anterior CVJ compartment in the patients before and after surgery when compared to the normal volunteers. There were no significant correlations (P = 0.06) noted for the APV at the CVJ between the normal control and patients, before or after surgery. CONCLUSION: In pediatric CMI patients, AMV for CSF within the cerebral aqueduct and anterior CVJ subarachnoid space are significantly elevated preoperatively and normalize following surgery. Given the biphasic CSF motion, measuring amplitude accounts for cranial and caudal flow. It may offer an alternative parameter to assess postsurgical outcome. J. Magn. Reson. Imaging 2016;44:463-470.

The association between Chiari malformation Type I, spinal syrinx, and scoliosis.

OBJECT Chiari malformation Type I (CM-I) is often found in patients with scoliosis. Most previous reports of CM-I and scoliosis have focused on patients with CM-I and a spinal syrinx. The relationship between CM-I and scoliosis in the absence of a syrinx has never been defined clearly. The authors sought to determine if there is an independent association between CM-I and scoliosis when controlling for syrinx status. METHODS The medical records of 14,118 consecutive patients aged ≤ 18 years who underwent brain or cervical spine MRI at a single institution in an 11-year span were reviewed to identify patients with CM-I, scoliosis, and/or syrinx. The relationship between CM-I and scoliosis was analyzed by using multivariate regression analysis and controlling for age, sex, CM-I status, and syrinx status. RESULTS In this cohort, 509 patients had CM-I, 1740 patients had scoliosis, and 243 patients had a spinal syrinx. The presence of CM-I, the presence of syrinx, older age, and female sex were each significantly associated with scoliosis in the univariate analysis. In the multivariate regression analysis, older age (OR 1.02 [95% CI 1.01-1.03]; p < 0.0001), female sex (OR 1.71 [95% CI 1.54-1.90]; p < 0.0001), and syrinx (OR 9.08 [95% CI 6.82-12.10]; p < 0.0001) were each independently associated with scoliosis. CM-I was not independently associated with scoliosis when controlling for these other variables (OR 0.99 [95% CI 0.79-1.29]; p = 0.9). CONCLUSIONS A syrinx was independently associated with scoliosis in a large pediatric population undergoing MRI. CM-I was not independently associated with scoliosis when controlling for age, sex, and syrinx status. Because CM-I is not independently associated with scoliosis, scoliosis should not necessarily be considered a symptom of low cerebellar tonsil position in patients without a syrinx.

Distribution of cerebellar tonsil position: implications for understanding Chiari malformation.

OBJECT: Prior attempts to define normal cerebellar tonsil position have been limited by small numbers of patients precluding analysis of normal distribution by age group. The authors' objective in the present study was to analyze cerebellar tonsil location in every age range. METHODS: Two thousand four hundred patients were randomly selected from a database of 62,533 consecutive patients undergoing MRI and were organized into 8 age groups. Magnetic resonance images were directly examined for tonsil location, morphology, and other features. Patients with a history or imaging findings of posterior fossa abnormalities unrelated to Chiari malformation (CM) were excluded from analysis. The caudal extent of the cerebellar tonsils was measured at the midsagittal and lowest parasagittal positions. RESULTS: The mean tonsil height decreased slightly with advancing age into young adulthood and increased with advancing age in the adult age range. An increasing age in the adult age range was associated with a decreased likelihood of a tonsil position 5 mm or more below the foramen magnum (p = 0.0004). In general, the lowest tonsil position in each age group was normally distributed. Patients with pegged morphology were more likely to have a tonsil location at least 5 mm below the foramen magnum (85%), as compared with those having intermediate (38%) or rounded (2%) morphology (p < 0.0001). Female sex was associated with a lower mean tonsil position (p < 0.0001). Patients with a lower tonsil position also tended to have an asymmetrical tonsil position, usually lower on the right (p < 0.0001). CONCLUSIONS: Cerebellar tonsil position follows an essentially normal distribution and varies significantly by age. This finding has implications for advancing our understanding of CM.

Homonymous hemianopia from infarction of the optic tract and lateral geniculate nucleus in deep cerebral venous thrombosis.

A 20-year-old man developed right homonymous hemianopia, hemiparesis, and hemisensory loss from deep cerebral venous thrombosis in the setting of high altitude. Approximately 3 months later, brain MRI showed encephalomalacia of the left optic tract and lateral geniculate nucleus, as well as signal abnormalities of the internal capsule and posterolateral thalamus. Homonymous hemianopia has previously been described in 1 case after deep cerebral venous thrombosis but without detailed neuroimaging features.

Chiari malformation Type I and syrinx in children undergoing magnetic resonance imaging.

OBJECT: Chiari malformation Type I (CM-I) with an associated spinal syrinx is a common pediatric diagnosis. A better understanding of the relative age-related prevalence and MR imaging characteristics of these associated conditions may lead to improved treatment decisions. METHODS: The authors performed a retrospective review of 14,116 consecutive individuals 18 years of age or younger who had undergone brain or cervical spine MR imaging at the University of Michigan between November 1997 and August 2008. In the patients with CM-I, demographic, clinical, and radiographic information was recorded. RESULTS: Five hundred nine children (3.6%) with CM-I were identified. Among these patients, 23% also had a spinal cord syrinx, and 86% of the syringes were found in the cervical spine. The MR imaging prevalence of CM-I with a syrinx was 1.2% in girls and 0.5% in boys (p < 0.0001). The severity of impaired CSF flow at the foramen magnum was associated with the amount of tonsillar herniation (p < 0.0001) and conformation of the tonsils (p < 0.0001). Patients with CM-I were treated surgically in 35% of cases; these patients exhibited more severe tonsillar herniation (p < 0.0001) and impaired CSF flow (p < 0.0001) as compared with those who did not undergo surgery. On imaging, 32% of all the patients with CM-I were considered symptomatic by the treating physician. Patients were more likely to be considered symptomatic if they were female, had a syrinx, displayed abnormal tonsillar pulsations, or had a greater amount of tonsillar herniation. CONCLUSIONS: In this study the authors describe the age-related prevalence and MR imaging characteristics of CM-I and its association with a syrinx and other abnormalities in a large group of children who underwent MR imaging for any indication. Syringes are more common in older children, in girls, and in patients with a greater degree of tonsillar descent and CSF flow impairment.

Natural history of Chiari malformation Type I following decision for conservative treatment.

OBJECT: The natural history of the Chiari malformation Type I (CM-I) is incompletely understood. The authors report on the outcome of a large group of patients with CM-I that were initially selected for nonsurgical management. METHODS: The authors identified 147 patients in whom CM-I was diagnosed on MR imaging, who were not offered surgery at the time of diagnosis, and in whom at least 1 year of clinical and MR imaging follow-up was available after the initial CM-I diagnosis. These patients were included in an outcome analysis. RESULTS: Patients were followed clinically and by MR imaging for a mean duration of 4.6 and 3.8 years, respectively. Of the 147 patients, 9 had new symptoms attributed to the CM-I during the follow-up interval. During this time, development of a spinal cord syrinx occurred in 8 patients; 5 of these patients had a prior diagnosis of a presyrinx state or a dilated central canal. Spontaneous resolution of a syrinx occurred in 3 patients. Multiple CSF flow studies were obtained in 74 patients. Of these patients, 23 had improvement in CSF flow, 39 had no change, and 12 showed worsening CSF flow at the foramen magnum. There was no significant change in the mean amount of cerebellar tonsillar herniation over the follow-up period. Fourteen patients underwent surgical treatment for CM-I. There were no differences in initial cerebellar tonsillar herniation or CSF flow at the foramen magnum in those who ultimately underwent surgery compared with those who did not. CONCLUSIONS: In patients with CM-Is that are selected for nonsurgical management, the natural history is usually benign, although spontaneous improvement and worsening are occasionally seen.

MRI of the pharynx in ischemic stroke patients with and without obstructive sleep apnea.

BACKGROUND: Obstructive sleep apnea (OSA) is common after stroke and associated with poor stroke outcomes. Whether OSA after acute stroke is caused by anatomic, physiologic, or both etiologies has not been studied. We therefore used brain magnetic resonance imaging (MRI) scans to assess oropharyngeal anatomy in stroke patients with and without OSA. METHODS: Patients within 7 days of ischemic stroke underwent nocturnal polysomnography. Sagittal T1-weighted MRI performed for clinical purposes was used to measure retropalatal distance, soft palatal length, soft palatal thickness, retroglossal space, and tongue length. Nasopharyngeal area and high retropharyngeal area were measured from axial T2-weighted images, and lateral pharyngeal wall thickness from coronal T1-weighted images. RESULTS: Among 27 subjects, 18 (67%) had OSA (apnea/hypopnea index (AHI)5). Demographics, vascular risk factors, and stroke severity were similar in the two groups. Median retropalatal distance was shorter in subjects with OSA (Wilcoxon rank-sum test, p=0.03). Shorter retropalatal distance was associated with higher AHI (linear regression, p=0.04). None of the other morphological characteristics differed. CONCLUSIONS: Anatomic difference between awake acute stroke patients with and without OSA shows that the sleep disorder cannot be attributed solely to sleep, sleeping position, or changes in neuromuscular control that are specific to the sleep state.

CT demonstration of dorsal midbrain hemorrhage in traumatic fourth cranial nerve palsy.

A 21-year-old man who suffered a traumatic brain injury from a motor vehicle accident recovered brain function except for an isolated left fourth cranial nerve palsy. Brain CT showed a focal hemorrhage in the right dorsal midbrain, directly in the brainstem path of what would become the left fourth cranial nerve. Although there has been previous imaging documentation of midbrain and cisternal hemorrhage in patients with isolated post-traumatic fourth cranial nerve palsy, this is the first report to show a large midbrain hemorrhage on CT. The mechanism is likely to be concussive impact of the dorsal midbrain on the tentorium cerebelli.

Vertebral arteriovenous fistula presenting as cervical myelopathy: a rapid recovery with balloon embolization.

A 24-year-old male presented with progressive cervical myelopathy of 2 months' duration. Magnetic resonance imaging of the cervical spine and angiography revealed a large arteriovenous fistula arising from the left vertebral artery. The present case highlights the clinical features and dramatic recovery following endovascular balloon occlusion of a giant cervical arteriovenous fistula.

Endonasal transsphenoidal pituitary surgery: is tumor volume a key factor in determining outcome?

PURPOSE: This study was conducted to evaluate the role of tumor volume in excision of pituitary adenomas. MATERIALS AND METHODS: A total of 20 patients with pituitary adenoma underwent surgical excision of the tumor by endonasal transsphenoidal approach. RESULTS: A preoperative tumor volume of more than 5 mL is associated with a 90.90% probability of residual tumor (P < .05, statistically significant). CONCLUSION: Tumor volume as a predicting factor for the surgical outcome is an evolving concept. Other factors determining the efficacy of tumor removal are parasellar and suprasellar extension.

Chronic sphenoid sinusitis revisited: comparison of multidetector axial sections, multiplanar reconstructions, and virtual sinoscopy with endoscopic sinus surgery.

OBJECTIVES: To assess the role of multidetector computed tomography (CT) and CT virtual sinoscopy in the evaluation of chronic sphenoid sinusitis and to compare the imaging findings with functional endoscopic sinus surgery. DESIGN: Prospective study. SETTING: Tertiary care teaching hospital. PATIENTS: Thirty patients with chronic sphenoid sinusitis referred for preoperative CT. INTERVENTIONS: Thin-section helical axial CT was performed using a multidetector CT scanner with multiplanar reformation (MPR) and volume-rendered or virtual sinoscopy images. Sixty sinuses were divided into quadrants for analysis. Extrasinus extension was labeled as the "fifth quadrant." MAIN OUTCOME MEASURES: Imaging findings were compared with those of functional endoscopic sinus surgery, and accuracy of the imaging modality was determined. RESULTS: Multidetector CT (axial CT and MPR) was found to be 100% sensitive, specific, and accurate in the evaluation of extent of sinusitis, status of the sinus septum, integrity of the optic nerve canal in relation to the sinus, and type of sinus pneumatization. Axial CT and MPR images showed sensitivity of 98% and specificity of 92% compared with functional endoscopic sinus surgery in evaluating the ostia. Regarding carotid canal integrity, axial CT and MPRs were 100% sensitive and 98% specific. Virtual sinoscopy showed sensitivity and specificity of 67% and 92%, respectively, for the 22 ostia that could be visualized and evaluated using this modality. CONCLUSIONS: Axial multidetector CT with secondary MPRs provide the necessary preoperative information regarding extent of disease and sphenoid sinus anatomy. Virtual sinoscopy is a navigational aid, an adjunct to endoscopy, and an educational tool for surgeons-in-training.

Imaging features of clear-cell ependymoma of the spinal cord.

A 10-year-old girl presented with increasing lower back pain without gait or sphincter disturbances. MRI demonstrated a large, intramedullary tumor at the level of the conus. The imaging findings were unlike those of a classic ependymoma or astrocytoma. Histopathologic examination demonstrated clear-cell ependymoma, which is a distinct entity. We found three cases of clear-cell ependymoma of the spinal cord reported in the literature. Clear-cell ependymoma of the spinal cord can be resected completely and needs to be recognized for its imaging features, benign course and favorable prognosis.

Computed tomography and ultrasonographic evaluation of metastatic cervical lymph nodes with surgicoclinicopathologic correlation.

The detection of cervical lymph nodal metastasis and carotid artery invasion by metastatic lymph nodes is an important issue in the management of head and neck malignancies. This study compared the evaluation of metastasis by palpation, ultrasonography (USG) and computed tomography (CT) in patients with known head and neck malignancies. Twenty-five consecutive patients with head and neck malignancy were prospectively evaluated for the presence of cervical lymphadenopathy and carotid artery invasion. All patients underwent clinical examination (palpation), USG and CT examination. A modified CT criteria was employed which yielded acceptable results for the detection of metastatic nodes. Radical neck dissection was performed for 26 neck sides, and the results of pre-operative evaluation were confirmed by the surgical and histopathological findings. Palpation, ultrasound and CT have comparable sensitivity in the determination of metastasis involving cervical lymph nodes. Thus palpation should be employed as the primary method of assessment of secondaries in the neck. However, palpation is less sensitive than CT and USG in the detection of carotid artery involvement, hence the clinical suspicion of arterial invasion should be confirmed by either CT or USG which have similar accuracy in the detection of carotid artery invasion.