Search Results

You are looking at 21 - 30 of 37 items for

  • Author or Editor: Yukihiko Fujii x
  • Refine by Access: all x
Clear All Modify Search
Restricted access

Interactive presurgical simulation applying advanced 3D imaging and modeling techniques for skull base and deep tumors

Clinical article

Makoto Oishi, Masafumi Fukuda, Naoki Yajima, Kenzo Yoshida, Machiko Takahashi, Tetsuya Hiraishi, Tetsuro Takao, Akihiko Saito, and Yukihiko Fujii

Object

In this paper, the authors' goal was to report their novel presurgical simulation method applying interactive virtual simulation (IVS) using 3D computer graphics (CG) data and microscopic observation of color-printed plaster models based on these CG data in surgery for skull base and deep tumors.

Methods

For 25 operations in 23 patients with skull base or deep intracranial tumors (meningiomas, schwannomas, epidermoid tumors, chordomas, and others), the authors carried out presurgical simulation based on 3D CG data created by image analysis for radiological data. Interactive virtual simulation was performed by modifying the 3D CG data to imitate various surgical procedures, such as bone drilling, brain retraction, and tumor removal, with manipulation of a haptic device. The authors also produced color-printed plaster models of modified 3D CG data by a selective laser sintering method and observed them under the operative microscope.

Results

In all patients, IVS provided detailed and realistic surgical perspectives of sufficient quality, thereby allowing surgeons to determine an appropriate and feasible surgical approach. Surgeons agreed that in 44% of the 25 operations IVS showed high utility (as indicated by a rating of “prominent”) in comprehending 3D microsurgical anatomies for which reconstruction using only 2D images was complicated. Microscopic observation of color-printed plaster models in 12 patients provided further utility in confirming realistic surgical anatomies.

Conclusions

The authors' presurgical simulation method applying advanced 3D imaging and modeling techniques provided a realistic environment for practicing microsurgical procedures virtually and enabled the authors to ascertain complex microsurgical anatomy, to determine the optimal surgical strategies, and also to efficiently educate neurosurgical trainees, especially during surgery for skull base and deep tumors.

Restricted access

Clinical characteristics of arteriovenous malformations in the cerebellopontine angle cistern

Kazuhiko Nishino, Hitoshi Hasegawa, Kenichi Morita, Masafumi Fukuda, Yasushi Ito, Yukihiko Fujii, and Mitsuya Sato

OBJECTIVE

Arteriovenous malformations (AVMs) in the cerebellopontine angle cistern (CPAC) are specific lesions that can cause neurovascular compression syndromes as well as intracranial hemorrhage. Although case reports describing the CPAC AVMs, especially those presenting with trigeminal neuralgia (TN), have been accumulating by degrees, the pathophysiology of CPAC AVMs remains obscure. The authors' purpose in the present study was to evaluate the clinical and radiographic features of CPAC AVMs as well as the treatment options.

METHODS

This study defined a CPAC AVM as a small AVM predominantly located in the CPAC with minimal extension into the pial surface of the brainstem and closely associated with cranial nerves. All patients with CPAC AVMs treated in the authors' affiliated hospitals over a 16-year period were retrospectively identified. Clinical charts, imaging studies, and treatment options were evaluated.

RESULTS

Ten patients (6 men and 4 women), ranging in age from 56 to 77 years (mean 65.6 years), were diagnosed with CPAC AVMs according to the authors' definition. Six patients presented with hemorrhage, 3 with TN, and the remaining patient developed a hemorrhage subsequent to TN. Seven AVMs were associated with the trigeminal nerve (Group V), and 3 with the facial-vestibulocochlear nerve complex (Group VII–VIII). All patients in Group VII–VIII presented with the hemorrhage instead of hemifacial spasm. Regarding angioarchitecture, the intrinsic pontine arteries provided the blood supply for all CPAC AVMs in Group V. In addition, 5 of 7 AVMs with hemorrhagic episodes accompanied flow-related aneurysms, although no aneurysm was detected in patients with TN alone. With respect to treatment, all patients with hemorrhagic presentation underwent Gamma Knife surgery (GKS), resulting in favorable outcomes except for 1 patient who experienced rebleeding after GKS, which was caused by the repeated rupture of a feeder aneurysm. The AVMs causing TN were managed with surgery, GKS, or a combination, according to the nidus-nerve relationship. All patients eventually obtained pain relief.

CONCLUSIONS

Clinical symptoms caused by CPAC AVMs occur at an older age compared with AVMs in other locations; CPAC AVMs also have distinctive angioarchitectures according to their location in the CPAC. Although GKS is likely to be an effective treatment option for the CPAC AVMs with hemorrhagic presentations, it seems ideal to obliterate the flow-related aneurysms before performing GKS, although this is frequently challenging. For CPAC AVMs with TN, it is important to evaluate the nidus-nerve relationship before treatment, and GKS is especially useful for patients who do not require urgent pain relief.

Restricted access

Interactive virtual simulation using a 3D computer graphics model for microvascular decompression surgery

Clinical article

Makoto Oishi, Masafumi Fukuda, Tetsuya Hiraishi, Naoki Yajima, Yosuke Sato, and Yukihiko Fujii

Object

The purpose of this paper is to report on the authors' advanced presurgical interactive virtual simulation technique using a 3D computer graphics model for microvascular decompression (MVD) surgery.

Methods

The authors performed interactive virtual simulation prior to surgery in 26 patients with trigeminal neuralgia or hemifacial spasm. The 3D computer graphics models for interactive virtual simulation were composed of the brainstem, cerebellum, cranial nerves, vessels, and skull individually created by the image analysis, including segmentation, surface rendering, and data fusion for data collected by 3-T MRI and 64-row multidetector CT systems. Interactive virtual simulation was performed by employing novel computer-aided design software with manipulation of a haptic device to imitate the surgical procedures of bone drilling and retraction of the cerebellum. The findings were compared with intraoperative findings.

Results

In all patients, interactive virtual simulation provided detailed and realistic surgical perspectives, of sufficient quality, representing the lateral suboccipital route. The causes of trigeminal neuralgia or hemifacial spasm determined by observing 3D computer graphics models were concordant with those identified intraoperatively in 25 (96%) of 26 patients, which was a significantly higher rate than the 73% concordance rate (concordance in 19 of 26 patients) obtained by review of 2D images only (p < 0.05). Surgeons evaluated interactive virtual simulation as having “prominent” utility for carrying out the entire surgical procedure in 50% of cases. It was evaluated as moderately useful or “supportive” in the other 50% of cases. There were no cases in which it was evaluated as having no utility. The utilities of interactive virtual simulation were associated with atypical or complex forms of neurovascular compression and structural restrictions in the surgical window. Finally, MVD procedures were performed as simulated in 23 (88%) of the 26 patients .

Conclusions

Our interactive virtual simulation using a 3D computer graphics model provided a realistic environment for performing virtual simulations prior to MVD surgery and enabled us to ascertain complex microsurgical anatomy.

Restricted access

Occurrence of metachronous pure germinomas long after treatment of a mixed germ cell tumor containing yolk sac tumor and germinoma

Case report

Shinya Jinguji, Kouichirou Okamoto, Junichi Yoshimura, Yuichiro Yoneoka, Ryousuke Ogura, Akihiko Saito, and Yukihiko Fujii

The authors report a rare case involving the occurrence of metachronous pure germinomas long after treatment of a mixed germ cell tumor (GCT) categorized as having a poor prognosis. A neurohypophysial germinoma occurred 4 years and 6 months after the initial treatment of a mixed pineal GCT containing a yolk sac tumor and a germinoma. Furthermore, intramedullary germinomas occurred 21 years after the initial treatment of the mixed GCT and 15 years after the second treatment of the neurohypophysial germinoma. The neurohypophysial germinoma was not confirmed histopathologically, but the intramedullary germinoma was histopathologically diagnosed as a pure germinoma. Serum α-fetoprotein levels at the second neurohypophysial and third intramedullary occurrences of the germinomas were less than 10 ng/ml. Therefore, no yolk sac components seemed to be contained in the tumors. The second neurohypophysial and third intramedullary germinomas might be recurrences of the germinoma component of the pineal mixed GCT, which consisted of a yolk sac tumor and a germinoma. However, it seems very unlikely that only the germinoma, categorized in the good prognosis group, would be the only one to recur. Hence, it seems plausible that both the second and the third occurrences of pure germinoma were de novo metachronous GCTs arising after the pineal mixed GCT was cured. The authors' case indicates the possibility of multicentric GCTs in the CNS.

Restricted access

Cranial nerve palsy following transvenous embolization for a cavernous sinus dural arteriovenous fistula: association with the volume and location of detachable coils

Kazuhiko Nishino, Yasushi Ito, Hitoshi Hasegawa, Bumpei Kikuchi, Junsuke Shimbo, Keiko Kitazawa, and Yukihiko Fujii

Object

Transvenous embolization (TVE) for the treatment of a cavernous sinus (CS) dural arteriovenous fistula (DAVF) occasionally causes cranial nerve palsy (CNP). Overpacking of coils is considered to result in CNP. The purpose of this study was to analyze the association of TVE-induced CNP with the volume and location of coils activated in the CS.

Methods

Thirty-one patients with CS DAVFs (33 lesions) underwent TVE.

Results

Cranial nerve palsy occurred or was aggravated in 13 cases (39.4%; CNP group). The cumulative volume of activated coils was significantly greater in the CNP group (0.241 ± 0.172 cm3) than in the non-CNP group (0.119 ± 0.075 cm3; p < 0.05). Of those lesions with > 0.2 cm3 of coil volume, 77.8% showed immediate aggravation or a new occurrence of CNP after TVE. Five lesions treated with a smaller volume of coils showed a delayed worsening or occurrence of CNP. In cases with induced oculomotor nerve palsy, coils had been densely packed in the superolateral part of the anterior CS. Dense packing in the lateral portion of the posterior CS frequently induced abducent nerve palsy. Although patients harboring lesions with a greater coil volume required a longer recovery time, newly developed or aggravated CNP, related to 84.6% of the lesions, resolved completely.

Conclusions

The cumulative volume and specific locations of coils in the CS correlated with TVE-induced CNP. Overpacking appeared to be the predominant cause of CNP; however, for CNP in cases involving smaller coil volumes, an alternative mechanism may be involved.

Restricted access

Diffusion tensor analysis of peritumoral edema using lambda chart analysis indicative of the heterogeneity of the microstructure within edema

Ken-ichi Morita, Hitoshi Matsuzawa, Yukihiko Fujii, Ryuichi Tanaka, Ingrid L. Kwee, and Tsutomu Nakada

Object. Histopathological studies indicate that cerebral edema associated with tumors (peritumoral edema) does not represent a single pathophysiological or clinical entity. In this study the authors investigated peritumoral edema by performing lambda chart analysis (LCA), a noninvasive technique that can be used to make visible and analyze apparent water diffusivity in tissues in vivo, and assessed the utility of LCA in differentiating high-grade gliomas from nonglial tumors.

Methods. The water diffusivity characteristics of peritumoral edema associated with four tumor groups—12 high-grade gliomas, five low-grade gliomas, 11 metastatic tumors, and 15 meningiomas—were assessed in 43 patients by performing magnetic resonance imaging with the aid of a 3-tesla magnetic resonance imaging system. In all tumor groups, peritumoral edema exhibited greater trace values and reduced anisotropy compared with normal white matter. Edema associated with high-grade gliomas had significantly higher trace values than edema associated with the other three tumor groups, although the anisotropic angles of those groups were comparable.

Conclusions. Lambda chart analysis identified two distinct types of peritumoral edema: edema associated with high-grade gliomas and edema associated with low-grade gliomas or nonglial tumors. The apparent water diffusivity was significantly greater in high-grade gliomas, whereas the anisotropy in these lesions was comparable to that of edema in other tumors. These findings indicated that water movement in areas of edema, predominantly in the extracellular spaces, was less restricted in high-grade gliomas, a phenomenon that likely reflected the destruction of the extracellular matrix ultrastructure by malignant cell infiltration and consequently greater water diffusion. Although preliminary, this study indicates that LCA could be used as a clinical tool for differentiating high-grade gliomas and for evaluating the extent of cellular infiltration.

Restricted access

Blood pressure in the artery distal to an intraarterial embolus during thrombolytic therapy for occlusion of a major artery: a predictor of cerebral infarction following good recanalization

Takatoshi Sorimachi, Yukihiko Fujii, Naoto Tsuchiya, Takeo Nashimoto, Masatsune Saito, Kenichi Morita, Yasushi Ito, and Ryuichi Tanaka

Object. The aim in this study was the investigation of back pressure in arteries distal to the occlusion site during intraarterial thrombolysis as well as the usefulness of back pressure measurement in combination with diffusion-weighted (DW) magnetic resonance (MR) imaging to predict the occurrence of ischemic lesions following good recanalization.

Methods. Twenty-five consecutive patients with severe hemiparesis caused by embolism of the internal carotid artery (10 patients) and the proximal middle cerebral artery (15 patients) were treated using intraarterial thrombolysis. Systolic back pressure, measured through a microcatheter in the artery just distal to the emboli, ranged from 22 to 78 mm Hg. According to an angiographic inclusion criterion for good recanalization—that is, recanalization of the M2 or more distal arteries at the end of thrombolysis—21 of 25 patients underwent evaluation in this study. In 14 patients volumes of low-density areas on computerized tomography (CT) scans obtained 2 months postthrombolysis were smaller in comparison with volumes of hyperintense areas on DW MR images acquired before treatment, whereas these low-density areas were larger in seven patients. Compared with those on initial DW MR images, the volume of abnormalities on CT scans obtained 2 months posttreatment were significantly reduced in patients with a systolic back pressure greater than 30 mm Hg (16 patients) than in those with a back pressure of 30 mm Hg or less (five patients) (p < 0.05). Systolic back pressures greater than 30 mm Hg were associated with significantly better modified Rankin Scale scores than those 30 mm Hg or less (p < 0.05).

Conclusions. Back pressure measurement in combination with DW MR imaging can be used to predict the occurrence of infarction as demonstrated on CT scans following thrombolysis.

Restricted access

Serial evaluation of axonal function in patients with brain death by using anisotropic diffusion-weighted magnetic resonance imaging

Toru Watanabe, Yoshiho Honda, Yukihiko Fujii, Miyako Koyama, and Ryuichi Tanaka

Object. The purposes of this study were to evaluate the serial changes in diffusion anisotropy of the brain, probably reflecting axonal function in brain-dead patients, and thus to explore the possibility of quantitatively estimating the risk of brain death.

Methods. Ten patients suffering from stroke with or without impending brain death and 10 healthy volunteers were studied using three-dimensional anisotropy contrast (3DAC) magnetic resonance (MR) axonography with the aid of a 1.5-tesla MR imaging system. To detect changes in the diffusion anisotropy of neural bundles, the corticospinal tract was evaluated.

Diffusion anisotropy of short axonal fibers decreased immediately after apparent brain death. Whereas the trichromatic coefficients of the corticospinal tract greatly diminished between 6 and 12 hours after apparent brain death, the coefficients of the corpus callosum and the optic radiation decreased in less time, that is, between 1 and 6 hours. The coefficients of these three bundles turned isotropic between 24 and 44 hours after apparent brain death.

Conclusions. Results of 3DAC MR axonography revealed that diffusion anisotropy of neural bundles diminished between 1 and 12 hours after the onset of apparent brain death, probably depending on the length of the bundles, and disappeared between 24 and 44 hours after the onset of brain death, which might reflect dynamic changes of axonal structure and indirectly herald axonal dysfunction. These findings seem to be greatly helpful in establishing an appropriate method to estimate the risk of brain death quantitatively and in forming the basis of future definitions of brain death.

Restricted access

Sturge-Weber syndrome associated with arteriovenous malformation in a patient presenting with progressive brain edema and cyst formation

Case report

Kazuhiko Nishino, Yasushi Ito, Takatoshi Sorimachi, Junsuke Shimbo, and Yukihiko Fujii

Sturge-Weber syndrome (SWS) is a neurocutaneous disorder presenting with a facial port-wine stain, along with an occipital leptomeningeal angiomatosis that is typically located ipsilateral to the stain. In this paper, the authors present a rare case of SWS associated with an arteriovenous malformation (AVM) instead of an angiomatosis in the ipsilateral occipital lobe. While the patient was in the care of the authors, the AVM progressively enlarged, and was accompanied by progressive stenoocclusive changes of the venous system. The resulting brain edema finally brought about a serious neurological condition 13 years after the initial diagnosis. Transarterial embolization and medical treatments decreased the edema. Subsequently, however, a large intraparenchymal cyst appeared, aggravating the patient's motor weakness. Aspiration of the cyst ameliorated these symptoms. The analysis of the fluid from the cyst revealed that it contained a very high concentration of protein. Although there is no proven pathogenic mechanism to explain these protein concentrations and the enlargement of the AVM, the authors hypothesize that the progressive edema resulted from a synergic augmentation of the inflow from the AVM and the progressive obstruction of venous drainage that is a hallmark of SWS. The formation of the cyst probably resulted from the blood vessel hyperpermeability that is inherent to SWS.

Free access

Visualization of cortical activation in human brain by flavoprotein fluorescence imaging

Daiju Mitsuhashi, Ryuichi Hishida, Makoto Oishi, Tetsuya Hiraishi, Manabu Natsumeda, Katsuei Shibuki, and Yukihiko Fujii

OBJECTIVE

To develop an innovative brain mapping and neuromonitoring method during neurosurgery, the authors set out to establish intraoperative flavoprotein fluorescence imaging (iFFI) to directly visualize cortical activations in human brain. The significance of iFFI was analyzed by comparison with intraoperative perfusion-dependent imaging (iPDI), which is considered the conventional optical imaging, and by performing animal experiments.

METHODS

Seven patients with intracerebral tumors were examined by iFFI and iPDI following craniotomy, using a single operative microscope equipped with a laser light source for iFFI and xenon lamp for iPDI. Images were captured by the same charge-coupled device camera. Responses to bipolar stimulation at selected points on the cortical surface were analyzed off-line, and relative signal changes were visualized by overlaying pseudocolor intensity maps onto cortical photographs. Signal changes exceeding 3 SDs from baseline were defined as significant. The authors also performed FFI and PDI on 10 mice using similar settings, and then compared signal patterns to intraoperative studies.

RESULTS

Signals acquired by iFFI exhibited biphasic spatiotemporal changes consisting of an early positive signal peak (F1) and a delayed negative signal peak (F2). In contrast, iPDI signals exhibited only 1 negative peak (P1) that was significantly delayed compared to F1 (p < 0.02) and roughly in phase with F2. Compared to F2 and P1, F1 was of significantly lower amplitude (p < 0.02) and located closer to the bipolar stimulus center (p < 0.03), whereas F2 and P1 were more widespread, irregular, and partially overlapping. In mice, the spatiotemporal characteristics of FFI and PDI resembled those of iFFI and iPDI, but the early positive signal was more robust than F1.

CONCLUSIONS

This is the first report in humans of successful intraoperative visualization of cortical activations by using iFFI, which showed rapid evoked cortical activity prior to perfusion-dependent signal changes. Further technical improvements can lead to establishment of iFFI as a real-time intraoperative tool.