Microstructural mechanisms of analgesia in percutaneous cervical cordotomy revealed by diffusion tensor imaging.

The purpose of this study is to demonstrate the potential of diffusion tensor imaging (DTI) to reveal structural mechanisms underlying spinal ablative procedures, including percutaneous radiofrequency cordotomy (PRFC). PRFC is a surgical procedure that produces analgesia through focal ablation of the lateral spinothalamic tract (STT), thereby interrupting the flow of pain information from the periphery to the brain. To date, studies regarding mechanisms of analgesia after PRFC have been limited to postmortem cadaveric dissection and histology. However, with recent advances in DTI, the opportunity has arisen to study the STT non-invasively in vivo. In this technical note, an individual with successful pain relief following unilateral STT PRFC was examined using DTI, with the contralateral STT serving as an internal control. PRFC substantially reduced rostrocaudal directional DTI signal in the STT from the lesion in the cervical spinal cord through the pons and mesencephalon. Our findings confirm that focal ablation and anterograde degeneration accompany the analgesic effects of PRFC. In vivo imaging of the STT with DTI may contribute to surgical targeting for PRFC procedures, better understanding of the therapeutic and untoward effects of PRFC, and a deeper understanding of spinothalamic contributions to nociception.

A Simplified Approach to Encephalitis and Its Mimics: Key Clinical Decision Points in the Setting of Specific Imaging Abnormalities.

RATIONALE AND OBJECTIVES: Infectious encephalitis is a relatively common cause of morbidity and mortality. Treatment of infectious encephalitis with antiviral medication can be highly effective when administered promptly. Clinical mimics of encephalitis arise from a broad range of pathologic processes, including toxic, metabolic, neoplastic, autoimmune, and cardiovascular etiologies. These mimics need to be rapidly differentiated from infectious encephalitis to appropriately manage the correct etiology; however, the many overlapping signs of these various entities present a challenge to accurate diagnosis. A systematic approach that considers both the clinical manifestations and the imaging findings of infectious encephalitis and its mimics can contribute to more accurate and timely diagnosis. MATERIALS AND METHODS: Following an institutional review board approval, a health insurance portability and accountability act (HIPAA)-compliant search of our institutional imaging database (teaching files) was conducted to generate a list of adult and pediatric patients who presented between January 1, 1995 and October 10, 2013 for imaging to evaluate possible cases of encephalitis. Pertinent medical records, including clinical notes as well as surgical and pathology reports, were reviewed and correlated with imaging findings. Clinical and imaging findings were combined to generate useful flowcharts designed to assist in distinguishing infectious encephalitis from its mimics. Key imaging features were reviewed and were placed in the context of the provided flowcharts. RESULTS: Four flowcharts were presented based on the primary anatomic site of imaging abnormality: group 1: temporal lobe; group 2: cerebral cortex; group 3: deep gray matter; and group 4: white matter. An approach that combines features on clinical presentation was then detailed. Imaging examples were used to demonstrate similarities and key differences. CONCLUSIONS: Early recognition of infectious encephalitis is critical, but can be quite complex due to diverse pathologies and overlapping features. Synthesis of both the clinical and imaging features of infectious encephalitis and its mimics is critical to a timely and accurate diagnosis. The use of the flowcharts presented in this article can further enable both clinicians and radiologists to more confidently differentiate encephalitis from its mimics and improve patient care.

Diffuse pontine lesions in children with neurofibromatosis type 1: making a case for unidentified bright objects.

Using an illustrative case of a presumed pontine unidentified bright object (UBO) with spontaneous lesion regression over 2 years, we review the importance of including UBOs in the differential diagnosis of children with confirmed or possible neurofibromatosis type 1 (NF1) who present with diffuse pontine enlargement and T2-weighted changes on MRI. Asymptomatic children with presumed NF1 and diffuse pontine lesions should not be treated with radiation and should not be biopsied. Prior reports of good prognosis associated with pontine glioma in patients with NF1 may have been unrecognized UBOs in some cases.

Efficacy of a cartoon and photograph montage storybook in preparing children for voiding cystourethrogram.

BACKGROUND: Undergoing voiding cystourethrogram (VCUG) can be distressing for children. OBJECTIVE: To assess the efficacy of a cartoon and photograph montage storybook in preparing children for VCUG. MATERIALS AND METHODS: Outpatient children (ages 2-14 years) who had VCUGs between December 2011 and June 2012 were randomly assigned to two groups; one group received the storybook a week before the procedure. Parents and guardians were asked to complete an anonymous survey rating their child's tolerance of the exam from 1 to 5, worst to best, immediately after VCUG. The VCUG technologist also rated the child's tolerance. RESULTS: Children prepared for VCUG with the storybook had less distress than those without. Results were analyzed by Cochran-Mantel-Haenszel and Cochran-Armitage Trend exact tests, a P value of both tests of 0.0092 indicating a statistically significant difference between the tolerance scores of children prepared with the storybook and those without. Effects of gender and history of VCUG were not statistically significant. Two-thirds of all children had no other source of information. CONCLUSION: The cartoon and photograph montage storybook format of preparing children for VCUG was effective in increasing their tolerance for the procedure. The storybook should be mailed out in advance because the majority of families did not pursue information on preparing their children for VCUG.

Residual thyroid tissue after thyroidectomy in a patient with TSH receptor-activating mutation presenting as a neck mass.

BACKGROUND: Activating mutations of the TSH receptor (TSHR) are rare, with few reported cases of long-term follow-up. CASE: We present a follow-up report on a patient with neonatal thyrotoxicosis known to have a rare activating mutation of the TSHR, a heterozygous substitution in exon 10 (p.Ile568Thr). Initial treatment included total thyroidectomy at age 2 ½ years, resulting in iatrogenic hypothyroidism and hypoparathyroidism. The patient was treated with levothyroxine replacement to maintain TSH levels within normal range, as well as calcitriol and calcium carbonate to treat postsurgical hypoparathyroidism. However, 4 years later, while euthyroid, he developed a palpable 1-cm midline neck mass. METHODS AND RESULTS: Functional imaging with 123-I thyroid scan demonstrated active thyroid tissue within the thyroglossal duct remnant and in the tracheoesophageal groove. Surgical removal of the neck mass revealed cytologically bland thyroid follicular cells. CONCLUSION: These findings suggest that even after total thyroidectomy, patients with TSHR-activating mutations are at risk to develop significant quantities of functional thyroid tissue related to the hypertrophy of residual foci in the thyroid bed and in the thyroglossal duct remnant. These residual foci may enlarge and secrete thyroid hormones autonomously, decreasing the patient's levothyroxine requirement. Surveillance with serial physical examination and biochemical monitoring is recommended; suspicious findings can be further evaluated with functional thyroid imaging (99-m technetium or radioiodine 123-I thyroid scans) to adequately identify residual foci of thyroid tissue, which may require further treatment with surgical excision or radioablation.

Perfusion-weighted MR imaging in cerebral lupus erythematosus.

RATIONALE AND OBJECTIVE: Neuropsychiatric systemic lupus erythematosus (NPSLE) is a diagnostically challenging, severe, and life-threatening condition, which is currently lacking a "gold standard." Our aim with this study is to look for magnetic resonance (MR) perfusion differences in NPSLE, SLE, and healthy control (HC) patients and correlate our findings with clinical parameters. MATERIALS AND METHODS: Twenty-four NPSLE patients, 21 SLE patients, and 21 HC underwent dynamic susceptibility contrast enhanced MR perfusion using a 3-T scanner. Nine prospectively selected intracranial regions of interest were placed in white and gray matter and the cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) values were calculated. Subjects underwent clinical evaluation with SLEDAI and serum antibodies. RESULTS: The SLE patients had higher CBF and CBV compared to the HC overall (P = .01) and in specific areas (P = .03-.048). SLE patients with signs of active disease (elevated SLEDAI and anti-double-stranded DNA) had significantly elevated CBV, CBF, and MTT in the posterior cingulate gyrus (P = .01-.02). No significant difference was seen in the magnetic resonance perfusion measurements of NPSLE patients compared to SLE and HC, although the NPSLE patients also showed higher CBV variability compared to the SLE (P = .0004) and HC cohort (P < .0001). CONCLUSION: SLE patients have increased CBV and CBF compared to healthy controls. The SLE patients with clinical markers for active disease have elevated CBV, CBF, and MTT in the posterior cingulate gyrus. NPSLE patients show increased variability in perfusion measurements, which may explain why susceptibility contrast enhanced MRI has not yet provided a specific target for NPSLE.

Spontaneous resolution of an infantile hemangioma in a dorsal root ganglion.

Infantile hemangiomas are tumors commonly seen in children. Few authors have reported infantile hemangiomas affecting the CNS, and there are no prior reports detailing spontaneous resolution of a histologically proven juvenile hemangioma within a dorsal root ganglion. The authors report the case of a newborn boy with a large cutaneous hemangioma in the midline of his back. Spinal MR images were obtained to rule out associated spinal cord tethering, and an intradural spinal lesion was unexpectedly discovered. Biopsy revealed an intradural infantile hemangioma within the dorsal root ganglion, and, based on this diagnosis, no resection was performed. Sixteen months following the biopsy, the cutaneous hemangioma had become involuted and the intradural hemangioma had completely resolved. The behavior of the intradural component in this case follows the natural history of many cutaneous infantile hemangiomas.

Olfactory groove meningioma: discussion of clinical presentation and surgical outcomes following excision via the subcranial approach.

OBJECTIVES/HYPOTHESIS: To describe surgical outcomes and radiographic features of olfactory groove meningiomas treated by excision through the subcranial approach. Special emphasis is placed on paranasal sinus and orbit involvement. STUDY DESIGN: Retrospective review of a series of patients. METHODS: Nineteen patients underwent excision of olfactory groove meningioma (OGM) via the transglabellar/subcranial approach between December 1995 and November 2009. Nine patients had previously undergone prior resection at outside institutions, and four had prior radiotherapy in addition to a prior excision. Transglabellar/subcranial surgical approach to the anterior skull base was performed. RESULTS: Tumor histology included three World Health Organization (WHO) grade III lesions, one WHO grade II lesion, and 15 WHO grade I lesions. Fourteen patients had evidence of extension into the paranasal sinuses, with the ethmoid sinus being most commonly involved. Kaplan-Meier estimates of mean overall and disease-free survival were 121.45 months and 93.03 months, respectively. The mean follow-up interval was 41.0 months, and at the time of data analysis three patients had recurrent tumors. Seven (36.8%) patients experienced a major complication in the perioperative period; there were no perioperative mortalities. Orbit invasion was observed in four patients, with optic nerve impingement in 11 patients. Of these, three patients had long-term diplopia. No patients experienced worsening of preoperative visual acuity. CONCLUSIONS: Olfactory groove meningiomas demonstrate a propensity to spread into the paranasal sinuses, particularly in recurrent cases. Given a tendency for infiltrative recurrence along the skull base, this disease represents an important area of collaboration between neurosurgery and otolaryngology. The subcranial approach offers excellent surgical access for excision, particularly for recurrences that involve the paranasal sinuses and optic apparatus.

Clival epidural hematoma in traumatic sixth cranial nerve palsies combined with cervical injuries.

Eight patients sustained a combination of clival epidural hematoma, traumatic sixth cranial nerve palsy (6 NP), and occipitocervical injury. This combination of features has been sparsely described. Whether the hematoma, which represents tectorial membrane injury, is merely a marker for 6 NP and occipitocervical injury or is causative is unresolved, but this imaging finding should alert examiners who note traumatic 6 NP to the need for detailed cervical imaging, as surgical stabilization of this region may be critical to prevent future spinal cord dysfunction.

Skew deviation as the initial manifestation of left paramedian thalamic infarction.

We describe a 73-year-old man who developed diplopia as the initial manifestation of a left thalamic infarction. By the time he reached the emergency department, clouded consciousness precluded localization of the lesion. Results of brain MRI were initially interpreted as negative. Ophthalmologic examination several hours later disclosed a small vertical ocular misalignment attributed to skew deviation. This finding led to careful scrutiny of the upper brainstem on MRI. Comparison of the diffusion, apparent diffusion coefficient, and exponential apparent diffusion coefficient MRI studies allowed a diagnosis of subtle left thalamic infarction. The recognition of skew deviation in this setting is important because it may be the most specific indicator of a brainstem lesion.

Improvement in mood and ideation associated with increase in right caudate volume.

BACKGROUND: The basal ganglia, particularly caudate, are hypothesized to play a role in affective and obsessive-compulsive disorders. The depressive syndrome is a feature of untreated Cushing's disease. The objective of this study was to test the hypothesis that after treatment of Cushing's disease reduces elevated cortisol, improvement in mood and related ideations are associated with increase in caudate volume. METHODS: In this longitudinal, interventional study of 23 patients with Cushing's disease, 24-hour urinary free cortisol, structural magnetic resonance imaging and behavioral measures were obtained prior to treatment and approximately one year after pituitary microadenomectomy. Five SCL-90-R subscales measuring change in mood, related ideations and physical symptoms were utilized. RESULTS: Partial correlations (adjusted for age and time since surgery) showed change in caudate, but not hippocampal, volume was significantly associated with change in behavioral SCL-90-R subscales, indicating selectivity for structure. Right but not left caudate showed associations, suggesting selectivity for lateralization. Right caudate volume increase was significantly associated with decreases in Depression, Anxiety, Obsessive-Compulsive, and Paranoid scores, but not with Somatization (physical symptoms), indicating specificity for behavioral but not physical variables. LIMITATIONS: A limitation is that relatively low-resolution scans were utilized. Although most likely not diminishing the significant findings, less sensitive methodology could lead to an increased probability of a type 2 error. CONCLUSIONS: These findings support the concept that caudate, and likely right caudate, participates in human brain circuitry regulating mood.

Patterns of cognitive change over time and relationship to age following successful treatment of Cushing's disease.

Chronically elevated levels of cortisol have been associated with changes in cognitive functioning and brain morphology. Using Cushing's disease as a model to assess the effects of high levels of cortisol on cognitive functioning, 27 patients with Cushing's disease were examined at baseline and three successive follow-up periods up to 18 months after successful surgical treatment. At all follow-up periods, patients were administered cognitive tests as well as measures of plasma and urinary free cortisol. Structural MRIs and a depression measure were taken at baseline and one-year follow-up. Results showed that there is a specific pattern of significant cognitive and morphological improvement following successful treatment. Verbal fluency and recall showed recovery, although brief attention did not. Age of participants was a significant factor as to when recovery of function occurred; younger patients regained and sustained their improvement in cognitive functioning more quickly than older participants. Improvement in verbal recall also was associated with a decrease in cortisol levels as well as an increase in hippocampal formation volume one year after treatment. Overall, these findings suggest that at least some of the deleterious effects of prolonged hypercortisolemia on cognitive functioning are potentially reversible, up to at least 18 months post treatment.

Multiple brain infarcts and Balint syndrome in aortic arch angiosarcoma.

A 50-year-old woman presented with subacute cognitive decline, impaired eye movements, and simultanagnosia, components of the Balint syndrome. She had relatively low blood pressure in the left arm and left finger clubbing. Brain imaging identified multiple acute infarcts. Transesophageal echocardiography showed no cardiac abnormalities but demonstrated a thickened aortic wall and an intraluminal aortic arch mass. The surgical specimen revealed angiosarcoma. Of the few reported angiosarcomas involving the aorta, most have been located in the abdominal segment. This is only the second reported case of aortic arch sarcoma presenting with stroke.

Nontuberculous mycobacterial infection of a metastatic brain neoplasm in an immunocompromised patient.

BACKGROUND: Nontuberculous mycobacterial infections occur in immunocompromised patients but so rarely involve the central nervous system (CNS) that they may not be included in a differential diagnosis of CNS lesions in such patients. OBJECTIVE: To illustrate a putative mechanism for nontuberculous mycobacterial infection of the CNS via breakdown of the blood-brain barrier by metastatic neoplasm. RESULTS: A 56-year-old man who had undergone renal transplantation in February 2003 and was taking an immunosuppressive regimen of mycophenolate mofetil and cyclosporine was seen in the emergency department after a syncopal episode. Head computed tomography revealed a single focal occipital lesion with vasogenic edema. Hospital admission and further workup led to diagnosis of metastatic carcinoma infected with nontuberculous mycobacteria in the setting of a disseminated nontuberculous mycobacterial infection. CONCLUSION: This case illustrates that breakdown of the blood-brain barrier by metastatic neoplasm may provide a route of access for a pathogen that is not normally seen in the CNS.

Papilledema in the assessment of ventriculomegaly.

To determine whether ventriculomegaly is associated with ongoing increased intracranial pressure (ICP), physicians often rely on corroborative imaging features such as altered periependymal signal, distortion of ventricular shape, subarachnoid space flattening, and an increase in ventricular size over time. In 2 patients with new headache and altered mental status, symptoms and ventriculomegaly were dismissed as long-standing and not reflective of current ICP elevation. In the first patient, ICP was considered normal because there were no corroborative imaging features of elevated ICP. In the second patient, ICP was considered normal because ventricular size was stable over a 1-year period. The diagnosis of ICP elevation was finally made by ICP monitoring after papilledema was recognized. Ventriculoperitoneal shunting rapidly resolved the papilledema and markedly improved mentation. Brain imaging may often be an unreliable guide to the presence of elevated ICP. In such patients, the finding of papilledema is a critical determinant of management.

Evaluation of the functional diffusion map as an early biomarker of time-to-progression and overall survival in high-grade glioma.

Diffuse malignant gliomas, the most common type of brain tumor, carry a dire prognosis and are poorly responsive to initial treatment. The response to treatment is typically evaluated by measurements obtained from radiographic images several months after the start of treatment; therefore, an early biomarker of tumor response would be useful for making early treatment decisions and for prognostic information. Thirty-four patients with malignant glioma were examined by diffusion MRI before treatment and 3 weeks later. These images were coregistered, and differences in tumor-water diffusion values were calculated as functional diffusion maps (fDM), which were correlated with the radiographic response, time-to-progression (TTP), and overall survival (OS). Changes in fDM at 3 weeks were closely associated with the radiographic response at 10 weeks. The percentage of the tumor undergoing a significant change in the diffusion of water (V(T)) was different between patients with progressive disease (PD) vs. stable disease (SD) (P < 0.001). Patients classified as PD by fDM analysis at 3 weeks were found to have a shorter TTP compared with SD (median TTP, 4.3 vs. 7.3 months; P < 0.04). By using fDM, early patient stratification also was correlated with shorter OS in the PD group compared with SD patients (median survival, 8.0 vs. 18.2 months; P < 0.01). On the basis of fDM, tumor assessment provided an early biomarker for response, TTP, and OS in patients with malignant glioma. Further evaluation of this technique is warranted to determine whether it may be useful in the individualization of treatment or evaluation of the response in clinical protocols.

Tectorial membrane injuries in children.

We report three cases of tectorial membrane injury in children. An increased interspinous ratio was identified on cervical spine radiographs. The tectorial membrane injuries were diagnosed by magnetic resonance imaging. The three children were restrained passengers in high-speed motor vehicle accidents, and all sustained polytrauma. Two children with partial tears of the tectorial membrane were immobilized in a halo, and one with a longitudinal tear of the tectorial membrane had an occiput-to-C2 fusion.

Functional diffusion map: a noninvasive MRI biomarker for early stratification of clinical brain tumor response.

Assessment of radiation and chemotherapy efficacy for brain cancer patients is traditionally accomplished by measuring changes in tumor size several months after therapy has been administered. The ability to use noninvasive imaging during the early stages of fractionated therapy to determine whether a particular treatment will be effective would provide an opportunity to optimize individual patient management and avoid unnecessary systemic toxicity, expense, and treatment delays. We investigated whether changes in the Brownian motion of water within tumor tissue as quantified by using diffusion MRI could be used as a biomarker for early prediction of treatment response in brain cancer patients. Twenty brain tumor patients were examined by standard and diffusion MRI before initiation of treatment. Additional images were acquired 3 weeks after initiation of chemo- and/or radiotherapy. Images were coregistered to pretreatment scans, and changes in tumor water diffusion values were calculated and displayed as a functional diffusion map (fDM) for correlation with clinical response. Of the 20 patients imaged during the course of therapy, 6 were classified as having a partial response, 6 as stable disease, and 8 as progressive disease. The fDMs were found to predict patient response at 3 weeks from the start of treatment, revealing that early changes in tumor diffusion values could be used as a prognostic indicator of subsequent volumetric tumor response. Overall, fDM analysis provided an early biomarker for predicting treatment response in brain tumor patients.