Shape and curvedness analysis of brain morphology using human fetal magnetic resonance images in utero

The 3-D morphological change has gained increasing significance in recent investigations on human fetal brains. This study uses a pair of new indices, the shape index (SI) and curvedness index (CVD), to quantify 3-D morphological changes in developing brains from 22 to 33 weeks of gestation. The SI was used to automatically locate the gyral nodes and sulcal pits, and the CVD was used to measure the degree of deviation of cortical shapes from a flat plane. The CVD values of classified regions were compared with two traditional biomarkers: cerebral volume and cortical surface area. Because the fetal brains dramatically deform with age, the age effect was controlled during the comparison between morphological changes and volume and surface area. The results show that cerebral volume, the cortical surface area, and the CVD values of gyral nodes and sulcal pits increased with gestational age. However, with age controlled, the CVD values of gyral nodes and sulcal pits did not correlate with cerebral volume, but the CVD of gyral nodes increased slightly with the cortical surface area. These findings suggest that the SI, in conjunction with the CVD, provides developmental information distinct from the brain volumetry. This approach provides additional insight into 3-D cortical morphology in the assessment of fetal brain development.

Direct measurement of the signal intensity of diffusion-weighted magnetic resonance imaging for preoperative grading and treatment guidance for brain gliomas

BACKGROUND

Magnetic resonance diffusion-weighted imaging (DWI) has been widely used clinically in imaging diagnosis of intracranial disorders. The purpose of current study was to present a quantitative method of direct measuring the DWI signal intensity of brain gliomas on the monitors of hospital picture archiving and communicating system (PACS) for grading gliomas.

METHODS

This study recruited 135 patients with treatment-naïve brain gliomas. Direct measurement of the signal intensity of selected tumoral regions of interest (ROIs) by DWI on the monitors of the hospital PACS was performed for all patients. From the measurements, we obtained three values, defined as DWI(T) (tumor), DWI(N) (the homologous normal-appearing area of the tumor ROI in the contralateral hemisphere), and DWI(WM) (normal-appearing white matter) in the contralateral frontal lobe. Two ratios, DWI(T/WM) and DWI(T/N), were obtained for each tumoral ROI. The same method was used for apparent diffusion coefficient (ADC) ratios of the tumoral ROI. Fractional polynomial regression and the Mann-Whitney U test were applied to determine the correlation between tumor grading, MIB-1 labeling index, and DWI and ADC ratios. Logistic regression models and receiver operating characteristic curve analysis were used to establish diagnostic models. Measurements of intraobserver and interobserver agreement were also made at 1-month interval.

RESULTS

The DWI ratios correlated positively with tumor grade and MIB-1 value (p < 0.01). Cut-off ratios of 1.62 for DWI(T/WM) and 1.47 for DWI(T/N) generated the optimal combination of sensitivity (0.82, 0.80), specificity (0.79, 0.86), and sound discriminating power, with an area under the curve of 0.87 and 0.84, respectively, to differentiate low-grade from high-grade gliomas. ADC ratios showed relatively worse sensitivity, specificity, and discriminating power than DWI ratios. Almost all intraobserver and interobserver measurements were within 95% agreement.

CONCLUSION

The proposed method - direct measuring of tumor signal intensity of DWI on PACS monitors - is feasible for grading gliomas in clinical neuro-oncology imaging services and has a high level of reliability and reproducibility.

Stent-assisted coil embolization of intracranial aneurysms: a single center experience

BACKGROUND

Endovascular detachable coil embolization has become an important method in the management of intracranial aneurysms. However, coil embolization alone may fail to treat some wide-neck aneurysms. Herein, we report our experience with and outcome of stent-assisted coil embolization (SACE) of intracranial aneurysms.

METHODS

Over a 5-year period, a total of 59 patients diagnosed with 63 intracranial aneurysms underwent SACE. Of the total 63 aneurysms, 6 aneurysms were treated by SACE as a salvageable procedure because of coil instability after detachment. There were 17 men and 42 women enrolled in the study, with ages ranging from 24 to 86 years (mean: 60 years). We retrospectively assessed the clinical data, aneurysm characteristics, and angiographic and clinical outcomes of all patient cases.

RESULTS

The mean aneurysm size was 9.4 mm, and the mean neck size was 5.5 mm. Clinical and angiographic follow-up exceeding 6 months were available in 51 and 40 patients, respectively. The mean clinical follow-up time was 28 months (range: 6-49 months). Successful stent deployment was found in 60 aneurysms (95%). Midterm total or subtotal angiographic aneurismal occlusion was obtained in 56 aneurysms (89%), with further thrombosis of the aneurismal sac occurring in 4 (10%). Stable coiling aneurysm was found in 24 (78%), aneurysm recurrence was observed in 5 (13%), and permanent procedural morbidity was observed in two patients (3.4%). During the follow-up period, there were no hemorrhagic events and no stent displacement.

CONCLUSION

Despite a modest procedural complication rate, and some evidence of aneurismal recurrence, SACE was proved to be both effective and safe in managing wide-neck intracranial aneurysms. Our results also demonstrated the midterm durability and stability of aneurysm treated by SACE. Furthermore, SACE can be a salvageable procedure in cases with coil instability after detachment.

Intraprocedure aneurysm rupture in embolization: clinical outcome with imaging correlation

BACKGROUND

Intraprocedural aneurysm rupture (IPAR) is the most feared complication of embolization for intracranial aneurysms. Here we report the immediate and long-term imaging outcomes of IPAR during embolization and the correlation with clinical outcomes.

METHODS

Of the 376 consecutive patients harboring 412 intracranial aneurysms who had underwent endovascular coil embolizations in the past 9 years, 10 patients (2.7% per patient, 2.4% per aneurysm) had IPAR. There were two men and eight women, with an age range of 40-71 years (mean: 52 years). Imaging findings, including immediate cerebral angiography, brain computed tomography (CT), and follow-up CT, were analyzed. Final clinical patient outcome was evaluated by modified Rankin scale (mRS).

RESULTS

The causes of the IPARs were coil protrusion (n=7), microcatheter perforation (n=2), or they were spontaneous (n=1). Nine cases involved previously ruptured aneurysms, while one was unruptured; aneurysmal location of the IPARs was the anterior (n=5) or posterior (n=4) communicating artery or the anterior cerebral artery (n=1). Angiographic cerebral hemodynamic compromise was observed in four patients and associated with poor clinical outcomes. Immediate CT showed contrast media and/or intracranial hemorrhage expansion in all the patients. Cerebral tissue loss due to ischemia and/or hemorrhagic occurred in six patients with more than 3 months of follow-up. On more than a 3-month clinical outcome, six patients presented with good recoveries (mRS: ≤ 2). One patient exhibited a moderate disability (mRS: 4), and three patients died (mRS: 6).

CONCLUSION

IPAR is an uncommon complication and usually occurs during the advancement of the coil into the aneurysm sac. Angiographic hemodynamics is an important indicator to determine the outcome of the IPAR. Brain CT demonstrates the progression of the IPAR and the cerebral tissue loss resulting from ischemic or hemorrhagic events.

Peritherapeutic quantitative flow analysis of arteriovenous malformation on digital subtraction angiography

BACKGROUND

Digital subtraction angiography (DSA) provides detailed hemodynamic information. However, the imaging interpretation is mainly based on the physician's experience and observation. We aimed to quantitatively study the peritherapeutic blood flow changes of a cerebral arteriovenous malformation (AVM) treated by embolization using optical flow estimation on DSA.

METHODS

A 37-year-old woman with an AVM in the right frontal lobe of her brain was enrolled. The optical flow method with a pixel-by-pixel measurement was applied to determine the blood flow in brain vessels on anterior-posterior and lateral DSA views before and after embolization.

RESULTS

A return toward normalization of blood flow as a result of embolization was determined semiquantitatively on the posttherapeutic DSA.

CONCLUSIONS

Optical flow analysis on DSA illustrated the potential of quantifying intracranial blood flows in patients with cerebral vascular disorders and the therapeutic effects.

Monitoring peri-therapeutic cerebral circulation time: a feasibility study using color-coded quantitative DSA in patients with steno-occlusive arterial disease

BACKGROUND AND PURPOSE

Intracranial hemodynamics are important for management of SOAD. This study aimed to monitor peri-stent placement intracranial CirT of patients with SOAD.

MATERIALS AND METHODS

Twenty-five patients received stent placement for extracranial ICA stenosis, and 34 patients with normal CirT were recruited as controls. Their color-coded DSAs were used to define the Tmax of selected intravascular ROI. A total of 20 ROIs of the ICA, OphA, ACA, MCA, FV, PV, OV, SSS, SS, IJV, and MCV were selected. rTmax was defined as the Tmax at the selected region of interest minus Tmax at the cervical segment of the ICA (I1 on AP view and IA on lateral view). rTmax of the PV was defined as intracranial CirT. Intergroup and intragroup longitudinal comparisons of rTmax were performed.

RESULTS

rTmax values of the normal cohorts were as follows: ICA-AP, 0.12; ICA-LAT, 0.10; A1, 0.28; A2, 0.53; A3, 0.81; M1, 0.40; M2, 0.80; M3, 0.95; OphA, 0.35; FV, 4.83; PV, 5.11; OV, 5.17; SSS, 6.16; SS, 6.51; IJV, 6.81; and MCV, 3.86 seconds. Before stent placement, the rTmax values of arterial ROIs, except A3 and M3, were prolonged compared with values from control subjects (P < .05). None of the rTmax of any venous ROIs in the stenotic group was prolonged with significance. After stent placement, the rTmax of all arterial ROIs shortened significantly, except A1and M3. Poststenting rTmax was not different from the control group.

CONCLUSIONS

Without extra contrast medium and radiation dosages, color-coded quantitative DSA enables real-time monitoring of peri-therapeutic intracranial CirT in patients with SOAD .

Selection of arterial input function for postprocessing of cerebral ct perfusion in chronic unilateral high-grade stenosis or occlusion of the carotid or middle cerebral artery

RATIONALE AND OBJECTIVES

We evaluated the effect of the arterial input function (AIF) on computed tomography perfusion (CTP) in patients with unilateral high-grade stenosis or occlusion in the carotid artery or middle cerebral artery without acute stroke.

MATERIALS AND METHODS

CTP datasets were retrospectively postprocessed using the same venous output function and different AIF selections: the second segment of the anterior cerebral artery (A2 AIF), the second segment of the middle cerebral artery (MCA) on the lesion side (affected M2 AIF), and M2 on the contralateral side (nonaffected M2 AIF). We measured CTP values in the region of interest (ROI) in the bilateral MCA territory and evaluated the lesion-to-contralateral ratios.

RESULTS

The mean and standard deviations of cerebral blood flow (CBF) on the normal side were similar to previously reported data only when using "non-affected M2 AIF." Selecting an "affected M2 AIF" overestimated the CBF and shortened the mean transit time (MTT) in normal and lesion areas. Selecting an "A2 AIF" may cause overestimation of CBF in the normal side in patients with nonaffected-side A1 hypoplasia or occlusion. The sensitivity of the CBF ratio or MTT ratio to detect these unilateral cerebrovascular diseases was 100% using "nonaffected M2 AIF for bilateral MCA ROIs" and 70% (CBF ratio) and 90% (MTT ratio) using "respective AIF."

CONCLUSION

The use of "nonaffected AIF for the bilateral MCA ROIs" was found to be the best of these AIF-ROI combinations in patients with chronic unilateral carotid or M1 severe stenosis or occlusion.

Dural sinus malformation with arteriovenous fistulae in a newborn: positive outcome following endovascular management

Dural sinus malformation (DSM) is an extremely rare and congenital cerebrovascular malformation that is associated with dural arteriovenous fistula and a large dural lake, which may mimic the clinical malformations of an infantile dural arteriovenous shunt or the vein of Galen. Early diagnosis and treatment of DSM is crucial in order to avoid irreversible brain injuries or heart failure. Here, we report an unusual case of extensive DSM that showed good clinical and angiographic results after endovascular embolization.

Regional quantification of developing human cortical shape with a three-dimensional surface-based magnetic resonance imaging analysis in utero

Although regional differences in cerebral volume have been revealed in developing human brains, little is known regarding the regionalization of cortical shape. This study documented the regional and quantitative shape difference of cortical surfaces for in utero normal fetal brains over a time period essential for the formation of primary cortical folding (22-33 weeks). Each brain surface with complete three-dimensional morphology was manually extracted from the reconstructed image, which combined surface information from three orthogonal magnetic resonance images in utero. An innovative parcellation was used to dissect the fetal brains into frontal, parietal, temporal and occipital lobes, and to avoid the determination of non-existent and immature sulci for young fetuses. Distinct cortical shapes were encoded by the shape index automatically. The results of this study show faster shape changes in the occipital lobe than in other regions. Both regional and global shape patterns show that the gyral surface smoothens, whereas the sulcal surface becomes more angular, with gestational age. In addition, the smoothing of gyri is related mainly to the changes in shape of gyral crowns. This study presents the regional differences in early gyrification from the novel aspect of shape. The results of shape pattern analysis for normal fetuses may act as a reference in assessments of prenatal brain pathology and in extensive comparisons between various life stages.

Change in treatment strategy for intracranial germinoma: long-term follow-up experience at a single institute

BACKGROUND

Previous intracranial germinoma (IG) studies have investigated the effect of different radiotherapy (RT) volumes and the necessity for adjunctive chemotherapy, but there is currently no consensus on the best treatment for this tumor.

METHODS

From January 1989 to December 2009, 80 IG patients (≤20 years old) were treated with various RT regimens. Of them, 14 patients had craniospinal irradiation (CSI) + primary boost (PB); 8 patients had whole-brain irradiation (WBI) + PB; 31 patients had whole ventricular irradiation (WVI) + PB; and 27 patients had focal RT only. Twenty-nine patients (36.2%) also received systemic chemotherapy (CHT). Survival was estimated by the Kaplan-Meier method and variables affecting survival were analyzed by the Cox proportional hazard model.

RESULTS

Eleven patients (13.8%) developed local recurrence or dissemination after treatment, and 10 of these patients were in the focal RT group. The 5-year relapse-free survival (RFS) for the CSI, WBI, WVI, and focal RT patients were 100%, 85.7%, 100%, and 84.6%, respectively (P = .001). The 5-year overall survival (OS) for CSI, WBI, WVI, and focal RT patients was 100%, 83.3%, 100%, and 87.9%, respectively (P = .125). Focal irradiation (P = .02) and initial use of CHT (P = .021) were negatively associated with RFS.

CONCLUSIONS

Focal RT plus CHT were associated with inferior control of IG and a higher incidence of CHT-related toxicities. Adjustment of the radiation volume to the whole ventricular system without CHT is sufficient for treatment of nondisseminated IGs, even with lower primary RT doses (<36 Gy).

Risk of post-vertebroplasty fracture in adjacent vertebral bodies appears correlated with the morphologic extent of bone cement

BACKGROUND

New fractures in adjacent vertebral bodies were found after percutaneous vertebroplasty. We evaluated the correlation between extent of polymethylmethacrylate cement and occurrence of post-vertebroplasty fractures in patients with osteoporosis.

METHODS

Totally 162 adjacent vertebral bodies with no fracture at the time of vertebroplasty and the distribution of cement in corresponding treated vertebral bodies of 98 patients were included for the evaluation. Length of follow-up after vertebroplasty was 734 ± 314 days (range, 366-1838 days). Based on proximity of bone cement to the adjacent vertebral body, cement extent was classified as disc level (the closest), endplate level, or trabecula level (the farthest).

RESULTS

Forty-one adjacent vertebrae had post-vertebroplasty fracture occurring 2-1038 days after vertebroplasty. The percentages of adjacent vertebral bodies having post-vertebroplasty fracture about cement extent were: disc level, 44; endplate level, 29; and trabecula level, 7.

CONCLUSION

Our study revealed that the risk of subsequent fracture in the adjacent vertebral bodies was correlated with the extent of bone cement after vertebroplasty. Preventive measures can be taken from this observation to reduce the percentage of post-vertebroplasty fracture in adjacent vertebral bodies.

Gamma knife surgery for cavernous hemangiomas in the cavernous sinus

BACKGROUND

Cavernous hemangioma in the cavernous sinus (CS) is a rare vascular tumor. Direct microsurgical approach usually results in massive hemorrhage. Radiosurgery has emerged as a treatment alternative to microsurgery.

OBJECTIVE

To further investigate the role of Gamma Knife surgery (GKS) in treating CS hemangiomas.

METHODS

This was a retrospective analysis of 7 patients with CS hemangiomas treated by GKS between 1993 and 2008. Data from 84 CS meningiomas treated during the same period were also analyzed for comparison. The patients underwent follow-up magnetic resonance imaging at 6-month intervals. Data on clinical and imaging changes after radiosurgery were analyzed.

RESULTS

Six months after GKS, magnetic resonance imaging revealed an average of 72% tumor volume reduction (range, 56%-83%). After 1 year, tumor volume decreased 80% (range, 69%-90%) compared with the pre-GKS volume. Three patients had > 5 years of follow-up, which showed the tumor volume further decreased by 90% of the original size. The average tumor volume reduction was 82%. In contrast, tumor volume reduction of the 84 cavernous sinus meningiomas after GKS was only 29% (P < .001 by Mann-Whitney U test). Before treatment, 6 patients had various degrees of ophthalmoplegia. After GKS, 5 improved markedly within 6 months. Two patients who suffered from poor vision improved after radiosurgery.

CONCLUSION

GKS is an effective and safe treatment modality for CS hemangiomas with long-term treatment effect. Considering the high risks involved in microsurgery, GKS may serve as the primary treatment choice for CS hemangiomas.

Gamma knife radiosurgery for central neurocytoma: retrospective analysis of fourteen cases with a median follow-up period of sixty-five months

OBJECT

Central neurocytoma (CN) is considered to be a benign neuronal tumor with possible atypical behavior. Microsurgery, radiation therapy (RT) and radiosurgery all have been used in treating this rare disease during the past decade. In this study, the authors present the experience with gamma knife radiosurgery (GKRS) on 14 patients with CN during a median follow-up period of 65 months and document the safety and efficacy of GKRS in the treatment of CN.

METHODS

Between November 1997 and December 2009, 14 patients pathologically diagnosed with CN were treated with GKRS. Follow-up magnetic resonance imaging (MRI) was performed at 6-month intervals. Tumor volume and adverse radiation effects (ARE) were documented to evaluate tumor response to GKRS. The Karnofsky Performance Scale (KPS) and neurological status were used to assess clinical outcome. The mean radiation dose prescribed to the tumor margin was 12.1 Gy (ranging from 11 to 13 Gy). The mean tumor volume was 19.6 ml (ranging from 3.5 to 48.9 ml). The mean follow-up period was 70 months (ranging from 30 to 140 months), and the median follow-up period was 65 months.

RESULTS

Tumor shrinkage was found in all patients at the final MRI follow-up. The mean volume reduction was 69% (ranging from 47 to 87%). No tumor progression, ARE or radiation-related toxicity developed in any of the cases. The KPS scores of all patients were the same or had increased, and the neurological functions were all stable without deterioration at the final follow-up.

CONCLUSION

In our observations, GKRS was found to be an effective and safe alternative as adjuvant therapy for pathology-confirmed CN. The tumor volume and functional outcome can be controlled with a favorable result in long-term observation. Compared with RT and microsurgery, GKRS plays an important role in the treatment of CN as a minimally invasive technique with low morbidity. Regular long-term MRI follow-up should be mandatory to document the tumor response and possible recurrence. Multicenter consortia should be considered for further investigation and evaluation of GKRS for such a rare tumor.

Venous hypertension and cerebral aneurysm rupture

To investigate the correlation between the sinus asymmetry and aneurysm rupture. We retrospectively reviewed all diagnostic and therapeutic conventional angiograms of patients with cerebral aneurysms in our hospital from January 2000 to April 2008. Cases were categorized according to gender, presence or absence of aneurysm rupture, and presence or absence of symmetric dural sinuses. Exclusion criteria included patients with underlying fibromuscular dysplasia, dissecting aneurysms, pseudoaneurysms, and the presence of arteriovenous malformations or fistulas. The venous pressure was measured by MR phase contrast with standard fluid dynamics notation as Poiseuille's Law. A total of 193 cases (131 females and 62 males) were included for Chi-squared analysis, which showed significant difference (p < 0.05) between aneurysm rupture and venous asymmetry in the entire group as well as in females, but not in males. There was an association between side of rupture and side of asymmetry as well as between the size of hemorrhage. Ruptured aneurysm is more frequent at the same side of dominant dural sinus than the side of hypoplasia venous sinus. MRA phase contrast is able to show the venous pressure gradient of asymmetrical dural sinuses. With our preliminary data, we propose that dural sinus asymmetry is associated with aneurysm rupture.

Heterotopic ossification after cervical total disc replacement: determination by CT and effects on clinical outcomes

OBJECT

Heterotopic ossification (HO) after cervical total disc replacement (TDR) has been reported to impede artificial disc motion. In all previously reported cases of HO, assessment was based on plain radiographs. The authors hypothesized that CT scan is a more sensitive and accurate detector. The aims of this study were to assess the actual incidence of HO and its effect on outcome in a cohort of patients undergoing cervical TDR with the Bryan disc and to compare HO detection by means of plain radiographs and CT.

METHODS

The authors retrospectively assessed data from medical records, radiological studies, and clinical evaluations of patients who underwent 1- or 2-level cervical TDR with the Bryan disc and were followed up for more than 12 months. The presence and grading of HO according to the McAfee classification were assessed by CT scan, and these findings were compared with findings on plain radiographs. Thirty-six patients (mean age 46.61 ± 7.24 years; range 29-60 years; 21 men and 15 women) who underwent Bryan TDR at 52 levels were included in the study. The mean duration of CT follow-up was 19.03 ± 4.64 months; the mean duration of clinical follow-up was 26.78 ± 7.20 months.

RESULTS

On the basis of CT, HO was identified in 18 (50%) of 36 patients and 25 (48.1%) of 52 levels treated. Grade 1 HO was present in 9 of the levels treated (17.3%), Grade 2 in 13 levels (25.0%), Grade 3 in 2 levels (3.8%), and Grade 4 in 1 level (1.9%). Nineteen (76%) of the 25 affected levels were in patients who had undergone 2-level TDR. There was no significant association with patient sex or disc pathology. There was a tendency for HO development among older patients, but this finding was not statistically significant (mean age 48.8 ± 6.8 in patients with HO vs 44.4 ± 7.2 in those without HO, p = 0.065). Although HO was found in 25 levels, 96.2% of the treated levels (50 of 52) had segmental range of motion on dynamic (flexion and extension) radiographs. The concordance between HO grading by CT and radiography was high, with an intraclass correlation coefficient of 0.822 (lower limit of 95% CI: 0.710, p < 0.001). Patients who had HO had the same clinical success rate as those who did not (94.4% vs 94.4%, p = 1.00). The visual analog scale scores for neck and arm pain were significantly improved in both the HO and the non-HO group.

CONCLUSIONS

The rate of HO detected by CT scan in this cohort of patients undergoing cervical TDR with a Bryan disc was 48.1% per level treated and 50% per patient with minimal limitation of segmental motion (96.2% of levels remained mobile), but plain radiograph is an acceptable detection tool. Two-level surgery has a higher risk of HO, although development of HO does not affect clinical outcome.

Large vestibular schwannomas treated by Gamma Knife surgery: long-term outcomes

OBJECT

Although radiosurgery has been well accepted as a treatment for small- to medium-sized vestibular schwannomas (VSs), its application in the treatment of large VSs remains controversial because of unfavorable effects such as tumor swelling and potential compression of the brainstem. The authors present a retrospective study spanning 17 years, during which 21 patients underwent Gamma Knife surgery (GKS) for large VSs. Long-term outcomes are reported, and possible factors affecting tumor responses to GKS are analyzed.

METHODS

Five hundred thirteen patients harboring VSs underwent GKS between March 1993 and October 2009. A large VS was defined as a tumor whose diameter was > 3 cm. This paper focuses on 21 patients who harbored large VSs ranging in volume from 12.7 to 25.2 cm(3) (mean 17.3 cm(3)) and were treated by GKS. Fourteen of these patients had undergone 1 or more craniotomies previously to remove the tumor. Seven patients underwent GKS alone because of patient preference or a poor clinical condition that precluded microsurgery with general anesthesia. The mean radiation dose directed to the tumor ranged from 15 to 17.5 Gy. The mean radiation dose prescribed to the tumor margin was 11.9 Gy (range 11-14 Gy). The mean follow-up period was 66 months (range 12-155 months), and the median follow-up period was 53 months.

RESULTS

The tumor control rate was 90.5% (19 of 21 lesions). No deterioration in facial nerve or trigeminal nerve function was noted. Disturbances in balance (some temporary) occurred in 5 patients. Three of the 21 patients developed initial tumor swelling, which required minor surgical interventions, including aspiration using an Ommaya reservoir or placement of a ventriculoperitoneal shunt. All 3 patients recovered satisfactorily after aspiration of an enlarging cyst or ventriculoperitoneal shunt placement. There was no significant correlation between tumor control and the following factors: patient age or sex, tumor volume, radiation dose, previous operation, presence of brainstem compression, petrous bone invasion, T2 signal ratio between tumor and brainstem, and presence of a cyst. However, there was a significant correlation between the T2 signal ratio between tumor and brainstem and the duration of tumor swelling (p = 0.003).

CONCLUSIONS

Treatment of large VSs remains a challenge to neurosurgeons regardless of whether they perform microsurgery or radiosurgery. Control of tumor growth and preservation of neurological function are the main goals of treatment. Although delayed microsurgery was required in 2 patients (9.5%), the satisfactory tumor control rate and excellent preservation of facial and trigeminal nerve function are the great advantages of radiosurgery. Radiosurgery is not only a practical treatment for patients with small- to medium-sized VSs, but it is also an excellent tool for treating larger tumors up to 25 cm(3). In selected cases, radiosurgery plays an important role in treating large VSs with satisfactory results.

Preserved motor-evoked potentials but without good motor recovery in a patient with decerebrate rigidity

The corticospinal tract is not incriminated in decerebrate rigidity (DR). However, this has not yet been proven in humans. We applied transcranial magnetic stimulation (TMS) in a decerebrate patient to support the hypothesis. A patient suffering from pontine hemorrhage with the fourth ventricular extension was admitted unconscious and in a decerebrate posture. Five days later, she regained consciousness but remained in a decerebrate posture. Motor-evoked potentials (MEPs) to TMS were measured 1 week after she had regained consciousness, and this provoked muscle responses in her hands and feet bilaterally. During the follow-up, the patient's muscle tone became persistently flaccid, although her strength increased to varying degrees in different body and limb muscles. She remained bedridden for 3 years after the stroke and could neither turn on the bed by herself nor perform skilled movements using her hands. The findings of TMS confirmed the animal studies in that the mechanism of decerebrate rigidity did not come through a damage of the corticospinal pathway. This also implies that a preserved corticospinal tract function cannot guarantee a good motor recovery in a stroke patient.

MIB-1 labeling index correlated with magnetic resonance imaging detected tumor volume doubling time in pituitary adenoma

OBJECTIVE

The purpose of this study was to evaluate whether MIB-1 labeling index (LI) could be used to predict growth velocity of residual pituitary adenomas after surgery.

MATERIALS AND METHODS

One hundred and sixty pituitary adenomas which had not received other treatment modality except for surgery were collected. Each of them had at least two post-operative magnetic resonance imaging (MRI) studies with an interval of at least 1 month apart. Tumor volume doubling time (TVDT) was calculated for those in which volume increased.

RESULTS

Post-operative tumor progression was noted in 54 (33.8%) cases, of which 39 (72.2%) cases were non-functioning adenomas. The MIB-1 LIs of the functioning and non-functioning adenomas were not significantly different. The median TVDT of these 54 cases was 34.6 months. The mean and median MIB-1 LI were 2.7 and 1.1 respectively (range 0.4-20.6). The MIB-1 LI was significantly correlated with log(2)(TVDT) (r=-0.363, P=0.007); when LI was <0.8, the TVDT of 90.5% cases was >or= 2 years.

CONCLUSIONS

Only one-third of the pituitary adenomas progressed after surgery, and their MIB-1 LIs were generally low. The MIB-1 LI was significantly correlated with the MRI detected TVDT of post-operative residual pituitary adenomas.

Distal marginal stenosis: a contributing factor in delayed carotid occlusion of a patient with carotid blowout syndrome treated with stent grafts

Distal marginal stenosis is rarely reported to be a factor associated with poor long-term patency of patients of head and neck cancers with carotid blowout syndrome treated with stent grafts. We report a case of laryngeal cancer with rupture of the right common carotid artery. A self-expandable stent graft was deployed, but bleeding recurred. Another stent graft was deployed for the pseudoaneurysm located distal to the first stent graft. Rebleeding occurred because of pseudoaneurysm formation from reconstituted branches of the right superior thyroid artery. We performed direct percutaneous puncture of the proximal superior thyroid artery for successful embolization. Distal marginal stenosis and asymptomatic thrombosis of the carotid artery were noted at 3.5- and 5-month follow-ups, respectively. We suggest aggressive early follow-up and reintervention for distal marginal stenosis by combined antibiotic therapy and angioplasty and stenting to improve the long-term patency of stent-graft deployment for management of carotid blowout syndrome.

Morphological regionalization using fetal magnetic resonance images of normal developing brains

Regional differences in human brain development during infancy have been studied for many years, but little is known about how regionalization of the brain proceeds during intrauterine life. We investigated the regionalization of cerebral volume and cortical convolutions based on the volumetric magnetic resonance images (MRIs) of 43 fetuses, ranging from 21 to 37 weeks of gestation. Two plausible parcellations of MRI are proposed, and curvature index together with gyrification index are used to quantify the regional cortical convolutions. Our results elucidate that the cortical foldings among different brain regions develop at comparable rates, suggesting a similar uniformity of changes in size of the cortical sheet in these regions over time. On the contrary, the growth of the cerebral volume presents regional difference, with the frontal and parieto-temporal regions growing significantly faster than other regions due to the contribution from expansion of basal ganglia. This quantitative regional information suggests that cerebral volume is not a relevant parameter to measure in relation to gyrification, and that the size of the cortical sheet is more likely to be directly related to cortical folding. The availability of quantitative regional information on normal fetal brains in utero will allow clinical application of this information when probing neurodevelopmental disorders in the future.