Neurosurgery 67:1745–1756, 2010 DOI: 10.1227/NEU.0b013e3181f74105
Deep brain stimulation (DBS) surgery is used for treating movement disorders, including Parkinson disease, essential tremor, and dystonia. Successful DBS surgery is critically dependent on precise placement of DBS electrodes into target structures. Frequently, DBS surgery relies on normalized atlas-derived diagrams that are superimposed on patient brain magnetic resonance imaging (MRI) scans, followed by microelectrode recording and macrostimulation to refine the ultimate electrode position. Microelectrode recording carries a risk of hemorrhage and requires active patient participation during surgery.
OBJECTIVE: To enhance anatomic imaging for DBS surgery using high-field MRI with the ultimate goal of improving the accuracy of anatomic target selection.
METHODS: Using a 7-T MRI scanner combined with an array of acquisition schemes using multiple image contrasts, we obtained high-resolution images of human deep nuclei in healthy subjects.
RESULTS: Superior image resolution and contrast obtained at 7 T in vivo using susceptibility-weighted imaging dramatically improved anatomic delineation of DBS targets and allowed the identification of internal architecture within these targets. A patient-specific, 3-dimensional model of each target area was generated on the basis of the acquired images.
CONCLUSION: Technical developments in MRI at 7 T have yielded improved anatomic resolution of deep brain structures, thereby holding the promise of improving anatomicbased targeting for DBS surgery. Future study is needed to validate this technique in improving the accuracy of targeting in DBS surgery.
Acta Neurochir (2010) 152:2029–2036. DOI 10.1007/s00701-010-0779-2
MRI has been utilized to localize the electrode after deep brain stimulation, but its accuracy has been questioned due to image distortion. Under the hypothesis that MRI is not adequate for evaluation of electrode position after deep brain stimulation, this study is aimed at validating the accuracy of MRI in electrode localization in comparison with CT scan. Methods Sixty one patients who had undergone STN DBS were enrolled for the analysis. Using mutual information technique, CT and MRI taken at 6 months after the operation were fused. The x and y coordinates of the centers of electrodes shown of CT and MRI were compared in the fused images to calculate average difference at five different levels. The difference of the tips of the electrodes, designated as the z coordinate, was also calculated. Results The average of the distance between the centers of the electrodes in the five levels estimated in the fused image of brain CT and MRI taken at least 6 months after STN DBS was 1.33 mm (0.1–5.8 mm). The average discrepancy of x coordinates for all five levels between MRI and CT was 0.56±0.54 mm (0–5.7 mm), the discrepancy of y coordinates was 1.06±0.59 mm (0–3.5 mm), and for the z coordinate, it was 0.98±0.52 mm (0–3.1 mm) (all p values <0.001). Notably, the average discrepancy of x coordinates at 3.5 mm below AC–PC level, i.e., at the STN level between MRI and CT, was 0.59±0.42 mm (0–2.4 mm); the discrepancy of y coordinates was 0.81±0.47 mm (0–2.9 mm) (p values<0.001). Conclusions The results suggest that there was significant discrepancy between the centers of electrodes estimated by CT and MRI after STN DBS surgery.
Neuroradiology. DOI 10.1007/s00234-010-0801-7
Diffusion-weighted imaging (DWI) can provide valuable structural information that may be useful for evaluating pathological changes of the lumbar nerve root. Diffusion-weighted magnetic resonance (MR) neurography has recently been introduced as an alternative way to visualize nerves, but to date, quantitative DWI and MR neurography have not been applied to evaluate the pathology of lumbar nerve roots.
Methods Our purpose was to visualize lumbar nerve roots and to analyze their morphology by MR neurography, and to measure the apparent diffusion coefficient (ADC) of lumbar nerve roots compressed by herniated disks using 1.5-T MR imaging. Ten consecutive patients (median age, 48.0 and range, 20–72 years) with monoradicular symptoms caused by a lumbar herniated disk and 14 healthy volunteers were studied. Regions of interests were placed on the lumbar roots at dorsal root ganglia (DRG) and distal spinal nerves on DWI to quantify mean ADC values. The spinal nerve roots were also visualized by MR neurography.
Results In the patients, mean ADC values were significantly greater in the compressed DRG and distal spinal nerves than in intact nerves. MR neurography also showed abnormalities such as nerve swelling at and below the compression in the symptomatic nerve root. Increased ADC values were considered to be because of edema and Wallerian degeneration of compressed nerve roots.
Conclusion DWI is a potential tool for analysis of the pathophysiology of lumbar nerve roots compressed by herniated disks.
Neurosurgery 67:1350–1358, 2010 DOI: 10.1227/NEU.0b013e3181ef2821
Embolization of spinal dural arteriovenous fistulae (SDVAFs) has emerged as an alternative to surgery. However, surgical disconnection is a simple and effective procedure.
OBJECTIVE: To review results and complications of surgical treatment of 154 consecutive SDAVFs.
METHODS: The records of 154 consecutive patients with SDAVFs were retrospectively reviewed.
RESULTS: There were 120 males and 34 females (male/female ratio 3.5:1, mean age 63.6 years). The SDAVFs were located at the thoracic level in 92 patients and at the lumbar and sacral spine levels in 45 and 15 patients, respectively. The most common presenting symptoms were motor dysfunction (65 patients), sensory loss (31 patients), and paresthesias without sensory loss (13 patients). The mean interval from symptom onset to definitive diagnosis was 24.7 months (median 12 months). Surgery resulted in complete exclusion of the fistula at first attempt in 146 patients (95%). There were no deaths or major neurological complications related to the surgery. Six percent of patients experienced subjective or objective worsening of preoperative symptoms and signs by the time of discharge that persisted at follow-up. Other surgical complications consisted of wound infection in 2 patients and deep venous thrombosis in 3. Eight patients were lost to follow-up; 141 patients (96.6%) experienced improvement (120 patients, 82.2%) or stability (21 patients, 14.4%) of motor function at last follow-up compared with their preoperative status. Other symptoms such as numbness, sphincter dysfunction, and dysesthesias/neuropathic pain improved in 51.5%, 45%, and 32.6%, respectively.
CONCLUSION: Surgical obliteration of SDAVFs is safe and very effective. Prognosis of motor function is favorable after surgical treatment.
Neuroradiology (2010) 52:1003–1010. DOI 10.1007/s00234-010-0671-z
“Brain surface motion imaging” (BSMI) is the subtraction of pulse-gated, 3D, heavily T2-weighted image of two different phases of cerebrospinal fluid (CSF) pulsation, which enables the assessment of the dynamics of brain surface pulsatile motion. The purpose of this study was to evaluate the feasibility of this imaging method for providing presurgical information about adhesions between meningiomas and the brain surface.
Methods Eighteen cases with surgically resected meningioma in whom BSMI was presurgically obtained were studied. BSMI consisted of two sets of pulse-gated, 3D, heavily T2-weighted, fast spin echo scans. Images of the systolic phase and the diastolic phase were obtained, and subtraction was performed with 3D motion correction. We analyzed the presence of band-like texture surrounding the tumor and judged the degree of motion discrepancy as “total,” “partial,” or “none.” The correlation between BSMI and surgical findings was evaluated. For cases with partial adhesions, agreements in the locations of the adhesions were also evaluated.
Results On presurgical BSMI, no motion discrepancy was seen in eight cases, partial in six cases, and total in four cases. These presurgical predictions about adhesions and surgical findings agreed in 13 cases (72.2%). The locations of adhesions agreed in five of six cases with partial adhesions.
Conclusion In the current study, BSMI could predict brain and meningioma adhesions correctly in 72.2% of cases, and adhesion location could also be predicted. This imaging method appears to provide presurgical information about brain/meningioma adhesions.
J Neurosurg 113:733–741, 2010. DOI: 10.3171/2010.3.JNS09370
The Onyx liquid embolic system (Onyx) was approved in the European Union in 1999 for embolization of lesions in the intracranial and peripheral vasculature, including brain arteriovenous malformations (AVMs) and hypervascular tumors. In 2001 a prospective, equivalence, multicenter, randomized controlled trial was initiated to support a submission for FDA approval. The objective of this study was to verify the safety and efficacy of Onyx compared with N-butyl cyanoacrylate (NBCA) for the presurgical treatment of brain AVMs.
Methods. One hundred seventeen patients with brain AVMs were treated with either Onyx (54 patients) or NBCA (63 patients) for presurgical endovascular embolization between May 2001 and April 2003. The primary end point was technical success in achieving ≥ 50% reduction in AVM volume. Secondary end points were operative blood loss and resection time. All adverse events (AEs) were reported and assigned a relationship to the Onyx or NBCA system, treatment, disease, surgery, or other/unknown. The Data Safety Monitoring Board adjudicated AEs, and a blinded, independent core lab assessed volume measurements. Patients were monitored through discharge after the final surgery or through a 3- and/or 12-month follow-up if resection had not been performed or was incomplete.
Results. The use of Onyx led to ≥ 50% AVM volume reduction in 96% of cases versus 85% for NBCA (p = not significant). The secondary end points of resection time and blood loss were similar. Serious AEs were also similar between the 2 treatment groups.
Conclusions. Onyx is equivalent to NBCA in safety and efficacy as a preoperative embolic agent in reducing brain AVM volume by at least 50%.
J Neurosurg Spine 13:371–380, 2010. DOI: 10.3171/2010.3.SPINE09399
The aim of this retrospective study was to evaluate the predictive value of diffusion tensor (DT) imaging with respect to resectability of intramedullary spinal cord tumors and to determine the concordance of this method with intraoperative surgical findings.
Methods. Diffusion tensor imaging was performed in 14 patients with intramedullary lesions of the spinal cord at different levels using a 3-T magnet. Routine MR imaging scans were also obtained, including unenhanced and enhanced T1-weighted images and T2-weighted images. Patients were classified according to the fiber course with respect to the lesion and their lesions were rated as resectable or nonresectable. These results were compared with the surgical findings (existence vs absence of cleavage plane). The interrater reliability was calculated using the κ coefficient of Cohen.
Results. Of the 14 patients (7 male, 7 female; mean age 49.2 ± 15.5 years), 13 had tumors (8 ependymomas, 2 lymphomas, and 3 astrocytoma). One lesion was proven to be a multiple sclerosis plaque during further diagnostic workup. The lesions could be classified into 3 types according to the fiber course. In Type 1 (5 cases) fibers did not pass through the solid lesion. In Type 2 (3 cases) some fibers crossed the lesion, but most of the lesion volume did not contain fibers. In Type 3 (6 cases) the fibers were completely encased by tumor. Based on these results, 6 tumors were considered resectable, 7 were not. During surgery, 7 tumors showed a good cleavage plane, 6 did not. The interrater reliability (Cohen κ) was calculated as 0.83 (p < 0.003), which is considered to represent substantial agreement. The mean duration of follow-up was 12.0 ± 2.9. The median McCormick grade at the end of follow-up was II.
Conclusions. These preliminary data suggest that DT imaging in patients with spinal cord tumors is capable of predicting the resectability of the lesion. A further prospective study is needed to confirm these results and any effect on patient outcome.
J Neurosurg 113:639–647, 2010.DOI: 10.3171/2010.3.JNS091385
A challenge associated with deep brain stimulation (DBS) in treating advanced Parkinson disease (PD) is the direct visualization of brain nuclei, which often involves indirect approximations of stereotactic targets. In the present study, the authors compared T2*-weighted images obtained using 7-T MR imaging with those obtained using 1.5- and 3-T MR imaging to ascertain whether 7-T imaging enables better visualization of targets for DBS in PD.
Methods. The authors compared 1.5-, 3-, and 7-T MR images obtained in 11 healthy volunteers and 1 patient with PD.
Results. With 7-T imaging, distinct images of the brain were obtained, including the subthalamic nucleus (STN) and internal globus pallidus (GPi). Compared with the 1.5- and 3-T MR images of the STN and GPi, the 7-T MR images showed marked improvements in spatial resolution, tissue contrast, and signal-to-noise ratio.
Conclusions. Data in this study reveal the superiority of 7-T MR imaging for visualizing structures targeted for DBS in the management of PD. This finding suggests that by enabling the direct visualization of neural structures of interest, 7-T MR imaging could be a valuable aid in neurosurgical procedures.
Neurosurgery 67:844-854, 2010 DOI: 10.1227/01.NEU.0000374684.10920.A2
Multidetector computerized tomography angiography (MDCTA) is now a widely accepted technique for the management of intracranial aneurysms.
OBJECTIVE: To evaluate its accuracy for the postoperative assessment of clipped intracranial aneurysms.
METHODS:We analyzed a consecutive series of 31 patients that underwent direct surgical clipping procedures of 38 aneurysms. A 64 slice MDCT scanner (Aquilion 64, Toshiba) was used and results were compared with digital subtraction angiographies (DSA). Two independent neuroradiologists analyzed the following data: examination quality, artifacts, aneurysm remnant, and patency of collateral branches. Interobserver agreement, sensitivity, and specificity were calculated.
RESULTS: Seventy-nine percent of the aneurysms were located in the anterior circulation. Significant artifacts were found with multiple and cobalt-alloy clips. According to DSA, remnants >2 mm were found in 21% of the cases, and 2 patients had one collateral branch occluded. Sensitivity and specificity of 64-MDCTA for the detection of aneurysm remnants were 50% and 100%, respectively. Sensitivity and specificity of 64-MDCTA for the detection of a significant remnant (>2 mm) and the detection of the occlusion of a collateral branch were, respectively, 67% and 100% and 50% and 100%. No relationship was found with the location, type, shape, size, or number of clips, but missed remnants tended to be larger with cobalt-alloy clips.
CONCLUSIONS: 64-MDCTA is a valuable technique to assess the presence of a significant postoperative remnant in single titanium clip application cases and might be useful for longterm follow-up. DSA remains the most accurate postoperative radiological examination.
Neurosurgery 00:000-000, 2010 DOI: 10.1227/01.NEU.0000374684.10920.A2
Multidetector computerized tomography angiography (MDCTA) is now a widely accepted technique for the management of intracranial aneurysms.
OBJECTIVE: To evaluate its accuracy for the postoperative assessment of clipped intracranial aneurysms.
METHODS:We analyzed a consecutive series of 31 patients that underwent direct surgical clipping procedures of 38 aneurysms. A 64 slice MDCT scanner (Aquilion 64, Toshiba) was used and results were compared with digital subtraction angiographies (DSA). Two independent neuroradiologists analyzed the following data: examination quality, artifacts, aneurysm remnant, and patency of collateral branches. Interobserver agreement, sensitivity, and specificity were calculated.
RESULTS: Seventy-nine percent of the aneurysms were located in the anterior circulation. Significant artifacts were found with multiple and cobalt-alloy clips. According to DSA, remnants >2 mm were found in 21% of the cases, and 2 patients had one collateral branch occluded. Sensitivity and specificity of 64-MDCTA for the detection of aneurysm remnants were 50% and 100%, respectively. Sensitivity and specificity of 64-MDCTA for the detection of a significant remnant (>2 mm) and the detection of the occlusion of a collateral branch were, respectively, 67% and 100% and 50% and 100%. No relationship was found with the location, type, shape, size, or number of clips, but missed remnants tended to be larger with cobalt-alloy clips.
CONCLUSIONS: 64-MDCTA is a valuable technique to assess the presence of a significant postoperative remnant in single titanium clip application cases and might be useful for longterm follow-up. DSA remains the most accurate postoperative radiological examination.
J Neurosurg 113:74–78, 2010. (DOI: 10.3171/2009.9.JNS09171)
In this paper, the authors’ goal was to compare the artifact induced by implanted (in vivo) adjustable shunt valves in spin echo, diffusion weighted (DW), and gradient echo MR imaging pulse sequences.
Methods. The MR images obtained in 8 patients with proGAV and 6 patients with Strata II adjustable shunt valves were assessed for artifact areas in different planes as well as the total volume for different pulse sequences.
Results. Artifacts induced by the Strata II valve were significantly larger than those induced by proGAV valve in spin echo MR imaging pulse sequence (29,761 vs 2450 mm3 on T2-weighted fast spin echo, p = 0.003) and DW images (100,138 vs 38,955 mm3, p = 0.025). Artifacts were more marked on DW MR images than on spin echo pulse sequencse for both valve types.
Conclusions. Adjustable valve–induced artifacts can conceal brain pathology on MR images. This should influence the choice of valve implantation site and the type of valve used. The effect of artifacts on DW images should be highlighted pending the development of less MR imaging artifact–inducing adjustable shunt valves.
Acta Neurochir (2010) 152:1197–1205. DOI 10.1007/s00701-010-0640-7
Early infarction that occurs at the time of initial subarachnoid hemorrhage (SAH) due to rupture of an aneurysm is a poorly understood phenomenon. We investigate the frequency of early infarction using diffusion-weighted images (DWI) at the time of admission. We then discuss the pathogenesis of infarction.
Materials and methods This study included 85 SAH patients who underwent serial DWI on admission. Early infarction detected by DWI and clinical features were investigated retrospectively.
Results The overall incidence of DWI-detected early infarction at the time of SAH onset was 8% (7 of 85 cases). In all seven patients, early infarctions were asymptomatic on admission. Types of early infarction seen on DWI included infarcts occurring in the territory of the vessel harboring a ruptured aneurysm (solitary, three cases) and infarcts occurring outside the territory of the vessel (multiple, two cases; solitary, two cases). Six of seven patients eventually developed delayed ischemic neurological deficit (DIND) and computed tomography (CT)-detected and DWI-detected delayed extensive infarction. Four of seven patients with early infarction had an unfavorable outcome. The occurrence of DWI-detected early infarction on admission was significantly correlated with delayed angiographic vasospasm, DIND, CT-detected delayed infarction, DWI-detected delayed infarction, and unfavorable outcome.
Conclusions In the present study, DWI-detected early infarction at the time of SAH onset was correlated with the occurrence of delayed extensive ischemic lesions. We believe that performing DWI at the time of admission is useful for evaluating the primary ischemic insult, which might play an important role in the pathogenesis of early brain injury and delayed vasospasm-related complications.
Eur Spine J (2010) 19:1087–1093. DOI 10.1007/s00586-009-1274-4
Currently, there are over 300,000 lumbar discectomies performed in the US annually without an objective standard for patient selection.
A prospective clinical outcome study of 200 cases with 5-year follow-up was used to develop and validate an MRI-based classification scheme to eliminate as much ambiguity as possible. 100 consecutive lumbar microdiscectomies were performed between 1992 and 1995 based on the criteria for ‘‘substantial’’ herniation on MRI. This series was used to develop the MSU Classification as an objective measure of lumbar disc herniation on MRI to define ‘‘substantial’’. It simply classifies herniation size as 1-2-3 and location as AB- C, with inter-examiner reliability of 98%. A second prospective series of 100 discectomies was performed between 2000 and 2002, based on the new criteria, to validate this classification scheme. All patients with size-1 lesions were electively excluded from surgical consideration in our study.
The Oswestry Disability Index from both series was better than most published outcome norms for lumbar microdiscectomy. The two series reported 96 and 90% good to excellent outcomes, respectively, at 1 year, and 84 and 80% at 5 years. The most frequent types of herniation selected for surgery in each series were types 2-B and 2-AB, suggesting the combined importance of both size and location.
The MSU Classification is a simple and reliable method to objectively measure herniated lumbar disc. When used in correlation with appropriate clinical findings, the MSU Classification can provide objective criteria for surgery that may lead to a higher percentage of good to excellent outcomes.
Neurosurgery 67:110-117, 2010 DOI: 10.1227/01.NEU.0000370920.44359.91
The sequelae of aneurysmal subarachnoid hemorrhage (SAH) include vasospasm and hydrocephalus.
OBJECTIVE: To assess whether intraventricular tissue plasminogen activator (tPA) results in less vasospasm, fewer angioplasties, or fewer cerebrospinal fluid shunting procedures.
METHODS: 41 patients (tPA group, Hunt and Hess 3, 4, 5) from 2007 to 2008 received intraventricular tPA and lumbar drainage for a minimum of 5 days (range 5-7 days) and were compared to a matched group of 35 patients from 2006 to 2007 (Control, HH 3, 4, 5). Statistical comparison was done by t test analysis or Fisher exact tests and data are expressed as average ± standard error of the mean.
RESULTS: There were no significant differences in demographic data, although the tPA group had a trend toward more surgical patients. The tPA group of patients had a significantly higher modified Fisher grade than controls (P < .001) and had a significantly better Hunt and Hess grade than controls (P < .03). The angioplasty rate was significantly lower among the tPA patients (15.0% ± 5.6) than controls (40.0% ± 8.5, P = .019). The number of days spent in severe vasospasm normalized over the 14-day monitoring period by transcranial Doppler was significantly lower in the tPA group (0.09 ± 0.02) than controls (0.17 ± 0.03). The shunt rate was significantly lower among tPA patients (17.5% ± 6.0) than controls (42.8% ± 8.6). There were 2 clinically silent tract hemorrhages in the tPA group (4.8%).
CONCLUSION: Intraventricular tPA is a safe and effective treatment for reducing both angioplasty and shunting rates in patients with SAH H&H Grades 3 to 5. A randomized trial is indicated.
Neurosurgery 67:94-99, 2010 DOI: 10.1227/01.NEU.0000370939.30003.D1
A precise definition of ventricular enlargement is important in the diagnosis of hydrocephalus as well as in assessing central atrophy. The Evans index (EI), a linear ratio between the maximal frontal horn width and the cranium diameter, has been extensively used as an indirect marker of ventricular volume (VV). With modern imaging techniques, brain volume can be directly measured.
OBJECTIVE: To determine reference values of intracranial volumes in healthy elderly individuals and to correlate volumes with the EI.
METHODS:Magnetic resonance imaging (3 T) was performed in 46 healthy white elderly subjects (mean age ± standard deviation, 71 ± 6 years) and in 20 patients (74 ± 7 years) with large ventricles according to visual inspection. VV, relative VV (RVV), and EI were assessed. Ventricular dilation was defined using VV and EI by a value above the 95th percentile range for healthy elderly individuals.
RESULTS: In healthy elderly subjects, we found VV = 37 ± 18 mL, RVV = 2.47 ± 1.17%, and EI = 0.281 ± 0.027. Including the patients, there was a strong correlation between EI and VV (R = 0.94) as well as between EI and RVV (R = 0.95). However, because of a wide 95% prediction interval (VV: ±45 mL; RVV: ± 2.54%), EI did not give a sufficiently good estimate of VV and RVV.
CONCLUSION: VV (or RVV) and the EI reflect different properties. The exclusive use of EI in clinical studies as a marker of enlarged ventricles should be questioned. We suggest that the definition of dilated ventricles in white elderly individuals be defined as VV >77 mL or RVV >4.96 %. Future studies should compare intracranial volumes with clinical characteristics and prognosis.
Neurosurgery 66:917-924, 2010 DOI: 10.1227/01.NEU.0000367801.35654.EC
Diffusion tensor imaging (DTI) parameters were investigated in patients with chronic idiopathic hydrocephalus to evaluate microstructural changes of brain tissue caused by chronic ventricular dilatation.
METHODS: Eleven patients fulfilling the criteria for possible or probable idiopathic normal pressure hydrocephalus and 10 healthy control subjects underwent MRI at 3 Tesla, including DTI with 12 gradient directions. Patients were scanned before lumbar cerebrospinal fluid (CSF) withdrawal tests. Differences in fractional anisotropy (FA) and mean diffusivity (MD) between patients and controls were assessed using 2 different methods: manual definition of regions of interest and a fully automated method, TBSS (Tract-Based Spatial Statistics). DTI parameters were correlated with clinical findings.
RESULTS: Compared with the control group, patients with chronic idiopathic hydrocephalus had significantly higher MD values in both the periventricular corticospinal tract (CST) and the corpus callosum (CC), whereas FA values were significantly higher in the CST but lower in the CC. DTI parameters of the CST correlated with the severity of gait disturbances.
CONCLUSION:Microstructural changes in periventricular functionally relevant white matter structures (CSF, CC) in chronic idiopathic hydrocephalus can be visualized using DTI. Further studies should investigate the change of DTI parameters after CSF shunting and its relation to neurologic outcome.
Acta Neurochir (2010) 152:817–825. DOI 10.1007/s00701-009-0588-7
Surgical outcome after microvascular decompression (MVD) for primary trigeminal neuralgia (TN) has been demonstrated as being related to the characteristics of the neurovascular compression (NVC), especially to the degree of compression exerted on the root. Therefore, preoperative determination of the NVC features could be of great value to the neurosurgeon, for evaluation of conflicting nature, exact localization, direction and degree of compression. This study deals with the predictive value of MRI in detecting and assessing features of vascular compression in 100 consecutive patients who underwent MVD for TN.
Methods. The study included 100 consecutive patients with primary TN who were submitted to a preoperative 3D MRI 1.5 T with T2 high-resolution, TOF-MRA, and T1-Gadolinium. Image analysis was performed by an independent observer blinded to the operative findings and compared with surgical data.
Findings. In 88 cases, image analysis showed NVC features that coincided with surgical findings. There were no false-positive results. Among 12 patients that did not show NVC at image analysis, nine did not have NVC at intraoperative observation, resulting in three false-negative cases. MRI sensitivity was 96.7% (88/91) and specificity 100% (9/9). Image analysis correctly identified compressible vessel in 80 of the 91 cases and degree of compression in 77 of the 91 cases. Kappa-coefficient predicting degree of root compression was 0.746, 0.767, and 0.86, respectively, for Grades I (simple contact), II (distortion), and III (marked indentation; p<0.01).
Conclusion. 3D T2 high-resolution in combination with 3D TOF-MRA and 3D T1-Gadolinium proved to be reliable in detecting NVC and in predicting the degree of the root compression
Acta Neurochir (2010) 152:793–802 DOI 10.1007/s00701-009-0465-4
The aim of our study was to evaluate the diagnostic efficacy of multislice computed tomographic angiography (MSCTA) regarding exclusion quality after aneurysm clipping.
Methods. Sixty patients (74 aneurysms) underwent microsurgical exclusion using titanium clips. The presence of aneurysm remnants on MSCTA was compared by a neuroradiologist to 2D digital subtraction angiography (DSA), which was considered as a reference examination. The contribution of 3D DSA was assessed in a subpopulation of 29 patients (35 aneurysms).
Results. With 2D DSA, six aneurysm remnants (8%) were diagnosed, and only five (7%) by MSCTA. The specificity and sensitivity were 98.5 and 83%, respectively. MSCTA failed to demonstrate one large remnant (>2 mm) because of clip artifacts (six clips). With 3D DSA six supplementary remnants were diagnosed. Two were large remnants blinded by vessel overlaps and clip artifacts. Four were small “dogeared” remnants (≤2 mm). No additional treatment was required for small remnants.
Conclusion. In the postoperative period, MSCTA was considered a useful tool to evaluate the large remnants as well as a non-invasive ulterior examination for suspected bifurcation. Nevertheless, 3D DSA is still required for an accurate evaluation of aneurysms treated by more than three clips.
Neurosurg Focus 28 (4):E3, 2010. DOI: 10.3171/2010.1.FOCUS09303
Obesity as a consequence of management of pediatric craniopharyngioma is a well-described phenomenon related to the degree of hypothalamic involvement. However, weight change and obesity have not been analyzed in adult patients. Therefore, the purpose of this study was 1) to evaluate the pattern of postoperative weight gain related to preoperative body mass index (BMI), 2) determine if postoperative weight gain is an issue in adult patients, and 3) develop an objective MR imaging grading system to predict risk of postoperative weight gain and obesity in adults treated for craniopharyngioma.
Methods. The authors retrospectively screened 296 patients with known craniopharyngioma for the following inclusion criteria: pathologically confirmed craniopharyngioma, index surgery at the authors’ institution, and operative weight and height recorded with at least 3 months of follow-up including body weight measurement. Patients aged 18 years or younger were excluded, yielding 28 cases for analysis. Cases of craniopharyngiomas were compared with age- and sex-matched controls (pituitary adenoma patients) to evaluate the pattern and significance of perioperative weight changes.
Results. Mean age was 46 ± 17 years at surgery, and 64% of the patients were male. Complete resection was achieved in 71% of cases. There was no correlation of preoperative BMI and postoperative weight gain testing in a linear model. Sixty-one percent and 46% of patients had postoperative weight gains greater than 4 and 9%, respectively. Comparing craniopharyngioma patients (cases) to age- and sex-matched controls, the preoperative BMIs were similar (p = 0.93) between cases (mean 28.9 [95% CI 30.9–26.9]) and controls (mean 29.3 [95% CI 31.9–26.7]). However, there was a trend to a greater mean postoperative weight change (percentage) in cases (10.1%) than in controls (5.6%) (p = 0.24). Hypothalamic T2 signal change and irregular contrast enhancement correlated and predicted higher-grade hypothalamic involvement. Furthermore, they can be used to objectively grade hypothalamic involvement as the authors propose. Progressive hypothalamic involvement correlated with larger postoperative weight gains (p = 0.022); however, hypothalamic involvement did not correlate with preoperative BMI (p = 0.5).
Conclusions. Postoperative weight gain in adult patients undergoing surgery for craniopharyngioma is a significant problem and correlates with hypothalamic involvement, as it does in pediatric patients. Finally, objective MR imaging criteria can be used to predict risk of postoperative weight gain and aid in grading of hypothalamic involvement.
Neurosurgery 67:1745–1756, 2010 DOI: 10.1227/NEU.0b013e3181f74105
