Relationship between Cough-Associated Changes in CSF Flow and Disease Severity in Chiari I Malformation: An Exploratory Study Using Real-Time MRI.

BACKGROUND AND PURPOSE: Currently no quantitative objective test exists to determine disease severity in a patient with Chiari I malformation. Our aim was to correlate disease severity in symptomatic patients with Chiari I malformation with cough-associated changes in CSF flow as measured with real-time MR imaging. MATERIALS AND METHODS: Thirteen symptomatic patients with Chiari I malformation (tonsillar herniation of ≥5 mm) were prospectively studied. A real-time, flow-sensitized pencil-beam MR imaging scan was used to measure CSF stroke volume during rest and immediately following coughing and relaxation periods (total scan time, 90 seconds). Multiple posterior fossa and craniocervical anatomic measurements were also obtained. Patients were classified into 2 groups by neurosurgeons blinded to MR imaging measurements: 1) nonspecific Chiari I malformation (5/13)-Chiari I malformation with nonspecific symptoms like non-cough-related or mild occasional cough-related headache, neck pain, dizziness, paresthesias, and/or trouble swallowing; 2) specific Chiari I malformation (8/13)-patients with Chiari I malformation with specific symptoms and/or objective findings like severe cough-related headache, myelopathy, syringomyelia, and muscle atrophy. The Spearman correlation was used to determine correlations between MR imaging measurements and disease severity, and both groups were also compared using a Mann-Whitney U test. RESULTS: There was a significant negative correlation between the percentage change in CSF stroke volume (resting to postcoughing) and Chiari I malformation disease severity (R = 0.59; P = .03). Mann-Whitney comparisons showed the percentage change in CSF stroke volume (resting to postcoughing) to be significantly different between patient groups (P = .04). No other CSF flow measurement or anatomic measure was significantly different between the groups. CONCLUSIONS: Our exploratory study suggests that assessment of CSF flow response to a coughing challenge has the potential to become a valuable objective noninvasive test for clinical assessment of disease severity in patients with Chiari I malformation.

Cough-Associated Changes in CSF Flow in Chiari I Malformation Evaluated by Real-Time MRI.

BACKGROUND AND PURPOSE: Invasive pressure studies have suggested that CSF flow across the foramen magnum may transiently decrease after coughing in patients with symptomatic Chiari I malformation. The purpose of this exploratory study was to demonstrate this phenomenon noninvasively by assessing CSF flow response to coughing in symptomatic patients with Chiari I malformation by using MR pencil beam imaging and to compare the response with that in healthy participants. MATERIALS AND METHODS: Eight symptomatic patients with Chiari I malformation and 6 healthy participants were studied by using MR pencil beam imaging with a temporal resolution of ∼50 ms. Patients and healthy participants were scanned for 90 seconds (without cardiac gating) to continuously record cardiac cycle-related CSF flow waveforms in real-time during resting, coughing, and postcoughing periods. CSF flow waveform amplitude, CSF stroke volume, and CSF flow rate (CSF Flow Rate = CSF Stroke Volume × Heart Rate) in the resting and immediate postcoughing periods were determined and compared between patients and healthy participants. RESULTS: There was no significant difference in CSF flow waveform amplitude, CSF stroke volume, and the CSF flow rate between patients with Chiari I malformation and healthy participants during rest. However, immediately after coughing, a significant decrease in CSF flow waveform amplitude (P < .001), CSF stroke volume (P = .001), and CSF flow rate (P = .001) was observed in patients with Chiari I malformation but not in the healthy participants. CONCLUSIONS: Real-time MR imaging noninvasively showed a transient decrease in CSF flow across the foramen magnum after coughing in symptomatic patients with Chiari I malformation, a phenomenon not seen in healthy participants. Our results provide preliminary evidence that the physiology-based imaging method used here has the potential to be an objective clinical test to differentiate symptomatic from asymptomatic patients with Chiari I malformation.

Physiology-based MR imaging assessment of CSF flow at the foramen magnum with a valsalva maneuver.

BACKGROUND AND PURPOSE: MR imaging is currently not used to evaluate CSF flow changes due to short-lasting physiological maneuvers. The purpose of this study was to evaluate the ability of MR imaging to assess the CSF flow response to a Valsalva maneuver in healthy participants. MATERIALS AND METHODS: A cardiac-gated fast cine-PC sequence with ≤15-second acquisition time was used to assess CSF flow in 8 healthy participants at the foramen magnum at rest, during, and immediately after a controlled Valsalva maneuver. CSF mean displacement volume VCSF during the cardiac cycle and CSF flow waveform App were determined. A work-in-progress real-time pencil-beam imaging method with temporal resolution ≤56 ms was used to scan 2 participants for 90 seconds during which resting, Valsalva, and post-Valsalva CSF flow, respiration, and HR were continuously recorded. Results were qualitatively compared with invasive craniospinal differential pressure measurements from the literature. RESULTS: Both methods showed 1) a decrease from baseline in VCSF and App during Valsalva and 2) an increase in VCSF and App immediately after Valsalva compared with values measured both at rest and during Valsalva. Whereas fast cine-PC produced a single CSF flow waveform that is an average over many cardiac cycles, pencil-beam imaging depicted waveforms for each heartbeat and was able to capture many dynamic features of CSF flow, including transients synchronized with the Valsalva maneuver. CONCLUSIONS: Both fast cine-PC and pencil-beam imaging demonstrated expected changes in CSF flow with Valsalva maneuver in healthy participants. The real-time capability of pencil-beam imaging may be necessary to detect Valsalva-related transient CSF flow obstruction in patients with pathologic conditions such as Chiari I malformation.

Cough-associated headache in patients with Chiari I malformation: CSF Flow analysis by means of cine phase-contrast MR imaging.

The purpose of this study was to analyze the CSF flow in patients with Chiari I to determine differences between patients with and without CAH. Thirty patients with Chiari I malformation underwent cine-PC CSF flow imaging in the sagittal plane. CSF flow pulsations were analyzed by placing regions of interest in the anterior cervical subarachnoid space. Maximum CSF systolic (craniocaudal) and diastolic (caudocranial) velocities as well as the durations of CSF systole and diastole (measured in fractions of the cardiac cycle) were determined. In the region of interest just below the foramen magnum, patients with CAH had a significantly shorter CSF systole and longer diastole (P=.02). A CSF diastolic length of ≥0.75 of the cardiac cycle was 67% sensitive and 86% specific for CAH. Our results indicate that Cine-PC imaging can show differences in CSF flow patterns in patients with Chiari I with and without CAH.

Increased cochlear fluid-attenuated inversion recovery signal in patients with vestibular schwannoma.

BACKGROUND AND PURPOSE: Elevated protein levels have been reported in perilymph of patients with vestibular schwannoma. Fluid-attenuated inversion recovery (FLAIR) imaging is sensitive to high protein contents in fluids. The purpose of this study was to investigate if in patients with unilateral vestibular schwannoma, cochlear FLAIR signal intensity on the affected side is increased compared with the unaffected side and control subjects. MATERIALS AND METHODS: Fifteen patients with unilateral vestibular schwannoma and 25 age-matched control subjects (without a history of hearing loss) were retrospectively evaluated. All patients and controls had routine 5-mm FLAIR and T1- and T2-weighted imaging of the brain. The signal intensity of both cochleae was evaluated by placing a small region of interest on FLAIR images. The signal intensity of the brain stem was also determined by placing a second region of interest. A ratio of cochlear signal intensity to brain stem signal intensity (CIBI ratio) was determined. A t test was used to compare the CIBI ratios. RESULTS: In patients, the mean CIBI ratio of the affected side was 0.89 +/- 0.18, and that of the unaffected side was 0.57 +/- 0.12. In control subjects, it was 0.51 +/- 0.07. The CIBI ratio of the affected side was significantly higher compared with the unaffected side (P < .001) and compared with control subjects (P < .001). CONCLUSION: Patients with vestibular schwannoma have increased cochlear FLAIR signal intensity on the affected side compared with the unaffected side and healthy subjects.

Deficits in acetylcholine homeostasis, receptors and behaviors in choline transporter heterozygous mice.

Cholinergic neurons elaborate a hemicholinium-3 (HC-3) sensitive choline transporter (CHT) that mediates presynaptic, high-affinity choline uptake (HACU) in support of acetylcholine (ACh) synthesis and release. Homozygous deletion of CHT (-/-) is lethal shortly after birth (Ferguson et al. 2004), consistent with CHT as an essential component of cholinergic signaling, but precluding functional analyses of CHT contributions in adult animals. In contrast, CHT+/- mice are viable, fertile and display normal levels of synaptosomal HACU, yet demonstrate reduced CHT protein and increased sensitivity to HC-3, suggestive of underlying cholinergic hypofunction. We find that CHT+/- mice are equivalent to CHT+/+ siblings on measures of motor co-ordination (rotarod), general activity (open field), anxiety (elevated plus maze, light/dark paradigms) and spatial learning and memory (Morris water maze). However, CHT+/- mice display impaired performance as a result of physical challenge in the treadmill paradigm, as well as reduced sensitivity to challenge with the muscarinic receptor antagonist scopolamine in the open field paradigm. These behavioral alterations are accompanied by significantly reduced brain ACh levels, elevated choline levels and brain region-specific decreased expression of M1 and M2 muscarinic acetylcholine receptors. Our studies suggest that CHT hemizygosity results in adequate baseline ACh stores, sufficient to sustain many phenotypes, but normal sensitivities to physical and/or pharmacological challenge require full cholinergic signaling capacity.

Glucagon-like peptide-2 (GLP-2) response to enteral intake in children during anti-cancer treatment.

BACKGROUND: Intestinal dysfunction is frequent in cancer and during anti-cancer treatment. Glucagon-like peptide-2 (GLP-2) is secreted in a nutrition-dependent manner from the intestinal enteroendocrine L-cells. It accelerates crypt cell proliferation and nutrient absorption, inhibits enterocyte apoptosis and decreases mucosal permeability. Lack of GLP-2 may increase the risk of malabsorption and intestinal bacterial translocation. The aim of this study is to evaluate meal stimulated secretion of GLP-2 in children with cancer undergoing anti-cancer treatment. METHODS: Plasma-GLP-2 analysis after an overnight fast and 1 hour after intake of a mixed test meal. Data on gastrointestinal toxicity, blood neutrophile counts and food records were included in the analysis. RESULTS: Forty-four meal stimulation tests were performed in 25 children (median age, 6.0 years; range, 2.5-19) during anti-cancer treatment. Median GI toxicity score was 5 (range, 0-15), and mean energy intake was 62.4% of recommended values. P-GLP-2 values increased from mean (SD) 38 (18) to 63 (51) pmol/l (P < 0.0001). Twelve of the meal stimulation tests (28%) resulted in a p-GLP-2 increase >2 fold, which is assumed to be the lower limit of normal values. The increase was strongly dependent on the energy intake (r = 0.62, P < 0.0001), while toxicity score and neutrophile count had no significant influence (multiple regression). CONCLUSION: In children treated with anti-cancer therapy, GLP-2 secretion seems to be normal if the enteral energy intake is sufficient. Insufficient GLP-2 secretion could influence the gastrointestinal problems seen in the children with a low enteral energy intake.

Simultaneous noncontiguous cervical spine injuries in a pediatric patient: case report.

OBJECTIVE AND IMPORTANCE: Noncontiguous traumatic injuries of the cervical spine in children are rare. We present the case of a child who simultaneously sustained a separation of the odontoid synchondrosis and a C6-C7 dislocation with a complete spinal cord injury. The management of simultaneous cervical spine injuries is discussed. CLINICAL PRESENTATION: A boy aged 4 years and 2 months was a restrained back-seat passenger involved in a head-on motor vehicle accident. The patient lacked neurological function below C7. Imaging studies revealed a separation of the odontoid synchondrosis as well as a traumatic dislocation of the spine at C6-C7. INTERVENTION: The patient was placed in a halo vest shortly after admission. Four days after his injury, he underwent a posterior wiring and fusion of C6 to C7. As the C6-C7 dislocation was reduced by posterior element wiring, intraoperative x-rays showed a gradual increase in the subluxation of C1 on C2. This increase in C1-C2 subluxation required intraoperative repositioning of the halo crown on the ventral halo vest posts to maintain acceptable C1-C2 alignment. Postoperatively, ideal alignment of the odontoid peg on the body of C2 could not be achieved by halo adjustments alone. The patient required a custom-made posterior neck cushion attached to the halo vest to maintain cervical lordosis and good alignment of the odontoid peg on the body of C2. CONCLUSION: Simultaneous traumatic cervical spine injuries in pediatric patients are rare. The intraoperative reduction of one spine injury can affect the alignment at the location of the second injury. In this case, a custom adjustment of the halo vest improved the alignment of the odontoid peg on the body of C2.

Tegmental defects and cerebrospinal fluid otorrhea.

Congenital tegmental defects that present as unsuspected cerebrospinal fluid (CSF) otorrhea are diagnostic and therapeutic challenges. We reviewed 5 such patients to determine an optimal strategy for evaluation. Five patients presented with watery otorrhea, 4 of them after ventilation tube placement, and only 1 with rhinorrhea. The preoperative analysis of middle ear effusion for beta(2)-transferrin was positive in 2/4, equivocal in 1/4 and false negative in 1/4. Computerized tomography (CT) revealed nonspecific tegmental defects in all 5 patients. Magnetic resonance imaging (MRI) demonstrated meningoencephalocele in 3/5 and dural irregularity in 1/5. Tegmental defects were confirmed at surgery in all cases, demonstrating meningocele or arachnoid granulations in 2/5 and encephalocele in 2/5 patients. We recommend a combination of beta(2)-transferrin analysis to verify CSF, high resolution CT (axial and coronal planes) to diagnose tegmental defects, and MRI (multiplanar) to evaluate the type of herniation. A combination mastoid and middle fossa approach for definitive repair is suggested.

Dopamine D(5) receptor immunolocalization in rat and monkey brain.

Dopamine D(5) receptor localization has been difficult because even the most specific ligands cannot distinguish between molecular subtypes of the D(1)-like receptor subfamily. Antifusion protein rabbit polyclonal antibodies directed against the C-terminus of human D(5) receptor were therefore developed for immunolocalization of the D(5) receptor protein in brain. The antibodies were characterized by immunoblot analysis and immunoprecipitation and used for light microscopic immunocytochemistry in rat and monkey brain. Affinity purified D(5) antibodies were specific for D(5) fusion protein as well as cloned and native D(5) receptor on Western blots, and D(5) antisera specifically immunoprecipitated solubilized, cloned D(5) receptor. Regional distribution of D(5) receptor immunoreactivity was consistent across species and correlated well with D(5) mRNA distribution previously reported in monkey brain. Immunoreactivity was widespread and tended to label perikarya and proximal dendrites of neurons in cerebral cortex, basal ganglia, basal forebrain, hippocampus, diencephalon, brainstem, and cerebellum. Neuropil was immunoreactive in olfactory bulb, islands of Calleja, cerebral cortex, superior colliculus, and molecular layer of cerebellum. The distribution of D(5) in brain was clearly different from that of other dopamine receptor subtypes, including D(1), the other member of the D(1)-like receptor subfamily. This unique distribution corroborates the idea that the D(5) receptor subtype has a distinct role in dopamine neurotransmission.

Meningiomas of the cerebellopontine angle.

BACKGROUND: Meningiomas of the cerebellopontine angle (CPA), although uniform in location, are diverse with regard to the site of dural origin and displacement of neurovascular structures. A study of patients with CPA meningiomas was undertaken to gain more information regarding the relationship between site of dural attachment, clinical presentation, operative approach, and outcome. METHODS: In this report, we retrospectively review 40 patients with CPA meningiomas managed surgically. RESULTS: Common clinical presentations were hearing loss, unsteadiness, and dysequilibrium. Findings upon physical examination included hearing loss (73%), cerebellar signs (32%), trigeminal neuropathy (16%), and facial nerve dysfunction (16%). The most common site of dural origin was the petrous ridge (anterior to the IAC [26%], posterior [21%], superior [18%], and inferior [16%]). Less common sites of dural origin included the tentorium (31%), the clivus (15%), the IAC (10%), and the jugular foramen (8%). Site of dural origin determined the direction of displacement of the facial/vestibulocochlear nerve bundle. The most common microsurgical complication was facial nerve dysfunction (30%). Gross total resection was achieved in 82% of cases, whereas 18% underwent subtotal resection. Two patients died. Follow-up ranged from three months to 13 years with three recurrences. CONCLUSIONS: CPA meningiomas displace the seventh and eighth cranial nerves in various directions depending on the site of dural origin. Total surgical excision can be accomplished in the majority of cases with acceptable morbidity.

Bone flap fixation with titanium clamps: a new technique.

BACKGROUND: Craniotomy bone flaps are replaced for both cosmetic and protective purposes. The purpose of this study was to determine the facility, strength, timing, and cost effectiveness of an alternative system for securing bone flaps. The system consists of titanium discs that clamp the bone flap to the skull edge. METHODS AND RESULTS: Ten cadaver craniotomy flaps each were reattached with either 24-gauge wire, miniplates, or titanium clamps. The titanium clamp system required significantly less time to fix than either wire or miniplates. The clamps were stronger than wire and cost less than miniplates. CONCLUSION: The titanium clamp system is a reasonable alternative to present craniotomy fixation methods with respect to ease of use, time consumption, strength, and relative cost.

Cryopreservation of semen from pubertal boys with cancer.

BACKGROUND: The possibility of cryopreservation of semen from adolescents has until now received only little attention. Therefore, we have investigated the possibility of cryopreservation of semen in adolescent boys with cancer. PROCEDURE: Forty-five boys, aged 13-18 years, admitted because of cancer during the period January 1, 1995 to July 31, 1998 were eligible. Semen was obtained after masturbation in the majority of the cases. In three boys, semen was preserved after penile vibration or electroejaculation in general anaesthesia. The semen samples were analysed for concentration, motility, and morphology according to the WHO guidelines. The sample was transferred into straws prior to cryopreservation at 196 degrees C in liquid nitrogen. RESULTS: Twenty-one boys delivered a semen sample for cryopreservation. Four boys were offered and accepted sperm banking but were not able to produce a sample. In 20 cases time did not allow an attempt of sperm banking, the boy was not assessed to be mature enough to deliver a semen sample, or the procedure was not accepted. The boys delivered 1-3 samples, and the total number of spermatozoa ranged from 0-210 millions. Median percentage of motile sperm was 50% (range 9-86%). Semen quality improved with age; however, a 13- year- old boy produced 75 million spermatozoa with 38% motile cells. CONCLUSIONS: Pubertal maturation should be assessed in all boys admitted for cancer, and the possibility of sperm banking should be discussed with the patient and his parents.

Intracranial mucocele as a complication of endoscopic repair of cerebrospinal fluid rhinorrhea: case report.

OBJECTIVE AND IMPORTANCE: Endoscopic repair of an anterior cranial fossa cerebrospinal fluid (CSF) fistula has gained widespread acceptance. We report a case of mucocele development at the site of an endoscopic CSF leak repair. CLINICAL PRESENTATION: A 46-year-old woman underwent functional endoscopic sinus surgery for nasal obstructive symptoms. The surgery was complicated by an intraoperative CSF leak from the posterior cribriform plate/anterior sphenoid, which was repaired immediately using bone and mucosa grafts. Two years postoperatively, a 13-mm anterior cranial base mass was found incidentally. This mass increased to 20 mm over the next year. INTERVENTION: The anterior cranial base mass was excised via a right frontal craniotomy and confirmed histologically to be a mucocele. CONCLUSION: Endoscopic repair of an anterior cranial base CSF fistula with mucosal grafts may lead to formation of a mucocele.

Temporal bone meningiomas.

Meningiomas involving the temporal bone may originate from arachnoid cell nests present within the temporal bone (intratemporal), but more frequently originate from arachnoid cell nests of the posterior or middle cranial fossa with secondary invasion of the TB (extratemporal). In this study, we retrospectively reviewed the charts of 13 patients with meningiomas involving the temporal bone who underwent surgery. Tumors of the posterior fossa with only temporal bone hyperostosis, but without invasion, were excluded. Patients presented primarily with otologic symptoms and signs. The tumors originated in the temporal bone (5/13), jugular foramen (4/13), petroclival region (2/13), the asterion (1/13) or the internal auditory meatus (1/13). All of the intratemporal meningiomas had the radiological appearance of en-plaque menigiomas. The tumor extended into the middle ear (11/13), eustachian tube (5/13), and/or the labyrinth (3/13). A gross total resection was achieved in 11 patients and a subtotal resection in 2 patients. The lower cranial nerves were infiltrated by tumor in 4 patients, and were sacrificed. At a mean follow-up of approximately 6 years, 12 patients are currently alive and doing well and 1 died from tumor progression. Six patients showed tumor recurrence and were reoperated on (5/6) or followed conservatively (1/6). Surgical treatment of temporal bone meningiomas is associated with high recurrence rate due to indiscreet tumor margins. Combined surgical approaches (temporal craniotomy and mastoidectomy) by neurosurgical and otological teams are recommended for meningiomas originating in the temporal bone.

NIAID AIDS vaccine research: a conversation with Dr. Carole Heilman. National Institute of Allergy and Infectious Diseases. Interview by Sarah Landry.

AIDS: Carole Heilman, the deputy director of NIAID's Division of AIDS, discusses recent progress and new directions in NIAID's HIV vaccine research program. Dr. Heilman discusses NIAID's progress towards the development of an AIDS vaccine, the issues that need to be addressed in order to move towards larger vaccine studies, recent changes in the NIAID HIV vaccine research program, and changes in the clinical evaluation components of the vaccine program. Dr. Heilman also explains how basic research could be integrated into clinical studies and highlights the creation of two new programs for vaccine design and production. Heilman indicates that vaccine research is on the right track, creating several approaches to vaccine development; the approach farthest along is a combination method incorporating a live vector and a recombinant subunit vaccine. International studies will help determine whether a universal vaccine is needed or if a regional vaccine is required for the prevailing HIV subtype in a specific area. Finally, Dr. Heilman suggests that research needs better assays for measuring cytotoxic T lymphocytes, a better understanding of immune system responsiveness, improved animal models of HIV infection, and an expansion of the methodology and creative designs for larger studies.^ieng