Functional MR Imaging Using BOLD Technique in Patients with Brain Tumors

PURPOSE: To reveal clinical usefulness of functional MRI (fMRI) using sensorymotor and language stimuli for demonstrating anatomic relationship between sensorimotor or language cortices and lesions in the planning of brain tumor surgery. MATERIALS AND METHODS: This study included 12 right-handed patients with brain tumors in or around sensorimotor or language cortices. Eleven patients were evaluated with primary motor and sensory stimuli. Of these patients, six patients were also evaluated with language stimuli. One patient was evaluated with language stimuli only. For fMR imaging, a 1.5T scanner was used and the EPI BOLD technique was employed. For postprocessing image, the SPM99 program and a program made by our department was utilized. We evaluated whether sensorimotor and language stimuli activate sensorimotor and language cortices. And also, clinical efficacy of revealing anatomic relationship between cerebral cortices and lesions for planning neurosurgical operation were evaluated. Finally, we compared post-operative neurologic function with pre-operative neurologic function in same patients. RESULTS: The fMRI examination was successful in identifying the functional cortices and depicting anatomic relationship between functional cortices and lesions in all patients. In nine patients of 11 patients with identified sensorimotor cortices, postoperative grade of manual motor test was not changed, compared with preoperative grade. Whereas postoperative improved than preoperative grade in one patient of remaining two patients, postoperative aggravated than preoperative grade in the other. This result was due to atherosclerotic lacunar infarction, regardless of tumor resection. Postoperative deficit of language function was not found in seven patients with identified language cortices. CONCLUSION: fMRI could be a helpful method for determining the best approach to neurosurgical treatment in patients with brain tumors in or around sensorimotor or language cortices.

MR Imaging and Histopathologic Findings of A Case of Cerebral Ganglioneurocytoma

We report a case of ganglioneurocytoma manifesting as a complex partial seizure in a young adult male. MR images depicted a well-marginated cystic mass with a heterogeneous solid portion abutting the dura in the parietal lobe. The solid portion showed minimal heterogeneous enhancement, and pressure erosion of the overlying calvarium had occurred. Following gross total resection, the clinical outcome was satisfactory, with no further seizures, and during the five-year follow-up period, the tumor did not recur.

MR Imaging of Optic Chiasmatic Glioma

PURPOSE: To evaluate the MR findings of optic chiasmatic glioma (OCG). MATERIALS AND METHODS: MR images were reviewed in 14 patients with histologically proven OCGs and one with neurofibromatosis type 1 (male: female=8:7, mean age=8.5 years). Tumors were evaluated retrospectively with respect to their size, involvement of the optic pathway, transverse/vertical diameter ratio based on the coronal plane, signal intensities, enhancement pattern, and the presence of a cyst or calcification. RESULTS: Tumors was measured 1.7-5.5 (mean, 3.3) cm in maximum diameter. In ten patients, the optic tracts were involved, and in three, the optic nerves. In 12 patients, tumors had a transverse/vertical diameter ratio of over one, and showed iso (n=5) or low signal intensity (n= 10) compared with gray matter at T1-weighted imaging and high signal intensity (n=15) at T2-weighted imaging. Cyst formations were seen in eight patients, and tumors were enhanced strongly and homogeneously in nine and peripherally in four. In seven there was associated hydrocephalus, and in one, calcification. CONCLUSION: OCG is a suprasellar tumor which can extend into the optic pathway, has a transverse/vertical diameter ratio of more than one, and shows strong and homogeneous enhancement. These MR imaging findings are useful for the differentiation of OCG from other suprasellar tumors.

Von Hippel-Lindau disease: A Case Report

Von Hippel-Lindau disease is an autosomal dominant disorder characterized by the presence of multiple benign and malignant tumors including hemangioblastomas of the retina and central nervous system, pancreatic cysts and tumors, renal cell carcinomas, pheochromocytomas and epididymal cystadenomas. We report the radiologic findings of a case of von Hippel-Lindau disease, describing the family history.

Intracranial Primary Mesenchymal Chondrosarcoma: A Case Report

We report a case of dural-based intracranial primary mesenchymal chondrosarcoma, initially thought to be a meningioma. This rare tumor should be included in the differential diagnosis of an aggresive dural-based lesion occurring in a young adult. A 27-year-old man presented with headache, nausea and vomiting, first experienced months earlier. Pre-enhanced CT revealed the presence of a well-marginated isodense mass with dense calcifications in the frontoparietal convexity, while MR images depicted a lobulated extra-axial mass with peritumoral edema. At T1-weighted imaging, the signal intensity of the mass was slightly low or than that of gray matter, while T2-weighted imaging demonstrated heterogeneous high signal intensity. Some portions of the tumor showed low signal intesnity at all sequences, suggesting the presence of calcification. After the injection of contrast medium, heterogeneous enhancement was observed. We report the radiologic findings of an intracranial primary mesenchymal chondrosarcoma, confirmed pathologically.

MR Imaging Findings of Gliosarcoma: Report of Three Cases

Gliosarcoma is a rare primary brain tumor composed of neoplastic glial cells and a sareomatous spindle-cell element. We report three cases of gliosarcoma, and describe their MR findings, which in many respects are very similar to those of malignant astrocytomas. Gliosarcomas are, however, more peripherally located, abutting and/or invading the dura mater, and at T2-weighted imaging their signal intensity is lower than is usually the case with malignant astrocyomas. Despite its rarity, the possibility of gliosarcoma should be considered when MR findings of this nature are apparent.

Perfusion MR Imaging in Gliomas: Comparison with Histologic Tumor Grade

OBJECTIVE: To determine the usefulness of perfusion MR imaging in assessing the histologic grade of cerebral gliomas. MATERIALS AND METHODS: In order to determine relative cerebral blood volume (rCBV), 22 patients with pathologically proven gliomas (9 glioblastomas, 9 anaplastic gliomas and 4 low-grade gliomas) underwent dynamic contrast-enhanced T2*-weighted and conventional T1- and T2-weighted imaging. rCBV maps were obtained by fitting a gamma-variate function to the contrast material concentration versus time curve. rCBV ratios between tumor and normal white matter (maximum rCBV of tumor / rCBV of contralateral white matter) were calcu-lated and compared between glioblastomas, anaplastic gliomas and low-grade gliomas. RESULTS: Mean rCBV ratios were 4.90'+/-1.01 for glioblastomas, 3.97'+/-0.56 for anaplastic gliomas and 1.75'+/-1.51 for low-grade gliomas, and were thus sig-nificantly different; p < .05 between glioblastomas and anaplastic gliomas, p <.05 between anaplastic gliomas and low-grade gliomas, p < .01 between glioblas-tomas and low-grade gliomas. The rCBV ratio cutoff value which permitted dis-crimination between high-grade (glioblastomas and anaplastic gliomas) and low-grade gliomas was 2.60, and the sensitivity and specificity of this value were 100% and 75%, respectively. CONCLUSION: Perfusion MR imaging is a useful and reliable technique for esti-mating the histologic grade of gliomas.

Congenital Glioblastoma Multiforme: A Case Report

Congenital glioblastoma multiforme is relatively rare accounting for 2-9% of all congenital brain tumors. We deseribe a case of congenital glioblastoma multiforme which occurred in the lateral ventricle. T1-weighted images revealed high signal intensity, with areas of internal low signal intensity, while T2-weighted images showed low signal intensity with focal internal high-signal portions. Post-contrast T1-weighted images depicted a lateral ventricular mass which extended to adjacent brain parenchyme and had a serpentine signal void representing internal vessel.

The Usefulness of Perfusion MR Imaging in Patients with Brain Tumors

PURPOSE: To determine the usefulness of perfusion weighted MR imaging in the assessment of relative cerebral blood volume(rCBV) in brain tumors. MATERIALS AND METHODS: Twenty-three patients with primary or metastatic brain tumors [nine gliomas (6 high grade and 3 low), six metastatic tumors, five meningiomas (4 benign and 1 atypical), two neurilemmomas and one hemangioblastoma] underwent perfusion-weighted and conventional MR imaging. A total of 240 perfusion MR images were obtained from four axial slices after rapid injection of contrast media using a gradient echo planar imaging pulse sequence, and this was followed by postprocessing of these images to give CBV maps. In order to calculate the rCBV of tumor to normal white matter, ROIs were defined on the CBV map of a tumor and its contralateral normal white matter. RESULTS: The rCBV ratio of tumors to contralateral normal side was as follows: high-grade glioma, 0.40-5.64(mean +/-SD = 2.91 0.95); low grade astrocytoma, 0.77 -1.66 (mean +/-SD = 1.15 +/-0.28); benign menin-gioma,2.06 -4.90 (mean +/-SD = 3.59 +/-0.84); atypical meningioma, 0.46 -1.18 (mean +/-SD = 0.72 +/-0.25); neurilemmoma, 1.45 -3.85 (mean +/-SD = 2.56 +/-0.92); and hemangioblastoma, 6.16 -8.35 (mean +/-SD = 7.02 +/-1.12). High grade gliomas were more hypervascular than low grade astrocytomas, and showed a variable range of relative cerebral blood volume. In metaststic cancer, CBV maps showed a relatively high and variable blood volume. Benign meningiomas exhibited high relative cerebral blood volume, while in the atypical meningioma with cystic degeneration, this volume was low. In neurilemmomas, a variable range of relative cerebral blood volume, was noted, while in the mural nodule of the hemangioblastoma, this volume was the highest. CONCLUSION: Perfusion-weighted MRI indicated the rCBV of various brain tumor lesions, and this suggests that the modality can provide a very useful means of assessing brain tumor vascularity.

Effect of Steroid on Brain Tumors and Surround Edemas: Observa tion with Regional Cere b ral Blood Volume (rCBV) Maps of Perfusion MRI

PURPOSE: To observe the hemodynamic change in brain tumors and peritumoral edemas after steroid treat-ment, and then nvestigate the clinical usefulness of perfusion MRI. MATERIALS AND METHODS: We acquired conventional and perfusion MR images in 15 patients with various in-tracranial tumors (4 glioblastoma multiformes, 4 meningiomas, 3 metastatic tumors, 1 anaplastic ependymo-ma, 1 anaplastic astrocytoma, 1 hemangioblastoma, and 1 pilocytic astrocytoma). For perfusion MR imaging, a 1.5T unit employing the gradient-echo EPI technique was used, and further perfusion MR images were ob-tained 2-10 days after intravenous steroid therapy. After processing of the raw data, regional cerebral blood volume (rCBV) maps were reconstructed. The maps were visually evaluated by comparing relative perfusion in brain tumors and peritumoral edemas with that in contralateral white matter. Objective evaluations were performed by comparing the perfusion ratios of brain tumors and peritumoral edemas. RESULTS: Visual evaluations of rCBV maps, showed that in most brain tumors (67%, 10/15), perfusion was high before steroid treatment and showed in (80%, 12/15) decreased afferwards. Objective evaluation, showed that in all brain tumors, perfusion decreased. Visual evaluation of perfusion change in peritumoral edemas revealed change in only one case, but objective evaluation indicated that perfusion decreased signifi-cantly in all seven cases. CONCLUSIONS: rCBV maps acquired by perfusion MR imaging can provide hemodynamic information about brain tumors and peritumoral edemas. Such maps could prove helpful in the preoperative planning of brain tumor surgery and the monitoring of steroid effects during conservative treatment.

Effect of Steroid on Brain Tumors and Surround Edemas: Observa tion with Regional Cere b ral Blood Volume (rCBV) Maps of Perfusion MRI

PURPOSE: To observe the hemodynamic change in brain tumors and peritumoral edemas after steroid treat-ment, and then nvestigate the clinical usefulness of perfusion MRI. MATERIALS AND METHODS: We acquired conventional and perfusion MR images in 15 patients with various in-tracranial tumors (4 glioblastoma multiformes, 4 meningiomas, 3 metastatic tumors, 1 anaplastic ependymo-ma, 1 anaplastic astrocytoma, 1 hemangioblastoma, and 1 pilocytic astrocytoma). For perfusion MR imaging, a 1.5T unit employing the gradient-echo EPI technique was used, and further perfusion MR images were ob-tained 2-10 days after intravenous steroid therapy. After processing of the raw data, regional cerebral blood volume (rCBV) maps were reconstructed. The maps were visually evaluated by comparing relative perfusion in brain tumors and peritumoral edemas with that in contralateral white matter. Objective evaluations were performed by comparing the perfusion ratios of brain tumors and peritumoral edemas. RESULTS: Visual evaluations of rCBV maps, showed that in most brain tumors (67%, 10/15), perfusion was high before steroid treatment and showed in (80%, 12/15) decreased afferwards. Objective evaluation, showed that in all brain tumors, perfusion decreased. Visual evaluation of perfusion change in peritumoral edemas revealed change in only one case, but objective evaluation indicated that perfusion decreased signifi-cantly in all seven cases. CONCLUSIONS: rCBV maps acquired by perfusion MR imaging can provide hemodynamic information about brain tumors and peritumoral edemas. Such maps could prove helpful in the preoperative planning of brain tumor surgery and the monitoring of steroid effects during conservative treatment.

Diffusion MR Imaging in Patients with Intracranial Tumors

PURPOSE: To assess the usefulness of diffusion-weighted MR imaging in patients with intracranial tumors. MATERIALS AND METHODS: Using the single-shot spin echo EPI technique on a 1.5T unit and two gradient steps(b values of 0, 900 s/mm2), diffusion-weighted MR images (DW-MRI) of 76 patients with various intracranial tumors including high-grade glioma (n=20), meningioma (n=15), metastasis(n=14), lymphoma (n=6), low-grade glioma (n=5), schwannoma (n=4), cerebellar hemangioblastoma (n=3), - and others- were obtained. The signal intensity of each tumor was visually assessed as one of four grades, and this and apparent diffusion coefficient(ADC) were analyzed in the solid and cystic portions of tumors, normal gray matter, white matter and CSF. RESULTS: Lymphomas, metastases, meningiomas, and high- and low-grade gliomas showed low ADC values in increasing order. Tumors showing high signal intensity on DW-MRI had low ADC values. Visual assessment whowed that solid portions of high-grade gliomas were significantly more hyperintense than those of low-grade gliomas. There was, however, no significant difference in ADCs between high- and low-grade gliomas. Lymphoma a and metastases showed significantly higher signal intensities on DW-MRI and lower ADCs than did high-grade gliomas. There were significant differences in signal intensities, as seen on DW-MRI, and in ADCs, between metastatic adenocarcinomas and non-adenocarcinomas. Schwannomas and cerebellar heman-gioblastomas showed low signal intensities and high ADC values. CONCLUSION: DW-MRI appears to provide an additional means of examining intracranial tumors, not available with conventional MRI, and may thus be helpful in the grading of gliomas and the differential diagnosis of some intracranial tumors.

Evaluation of Therapeutic Effect of Acoustic Schwannoma After Gamma-Knife Radiosurgery using Follow-up MRI

PURPOSE: To evaluate, using short-term follow-up MR imagings, the usefulness of gamma-knife radiosurgery in patients with acoustic schwannoma. MATERIALS AND METHODS: In 34 patients (M:F=11:23, aged 11 -69 years) with acoustic schwannoma, eleven of whom had undergone microsurgical resection prior to gamma-knife radiosurgery, we retrospectively reviewed the serial MR imaging findings obtained before and after this procedure. Analysis focused on post-surgical changes in tumor volume and intratumoral enhancement, and the follow-up period ranged from 3 to 44 months. RESULTS: Follow-up imaging revealed that after radiosurgery, tumor size had decreased in 17 cases (50%), was unchanged in 14 (41.2%), and had increased in three (8.8%). Local tumor control was achieved in 31 of 34 cases (91.2%). Objectively defined tumor shrinkage was seen within 3 to 24 (median, 12) months of treatment, the rate of shrinkage increasing with longer follow-up. Three to 16 (median, 6) months after treatment, loss of central tumor enhancement was evident in 28 cases(82.4%). In 25 of 28 patients with intratumoral necrosis (89.3%), tumors were either smaller of their size was unchanged. Three to six (mean, 3.6) months after treatment, five cases demonstrated a transient size increase. CONCLUSION: Gamma-knife radiosurgery effectively controlled the growth of acoustic schwannoma, and intra-tumoral necrosis appears to be a predictable sign for decreased tumor size.

Evaluation of Therapeutic Effect of Acoustic Schwannoma After Gamma-Knife Radiosurgery using Follow-up MRI

PURPOSE: To evaluate, using short-term follow-up MR imagings, the usefulness of gamma-knife radiosurgery in patients with acoustic schwannoma. MATERIALS AND METHODS: In 34 patients (M:F=11:23, aged 11 -69 years) with acoustic schwannoma, eleven of whom had undergone microsurgical resection prior to gamma-knife radiosurgery, we retrospectively reviewed the serial MR imaging findings obtained before and after this procedure. Analysis focused on post-surgical changes in tumor volume and intratumoral enhancement, and the follow-up period ranged from 3 to 44 months. RESULTS: Follow-up imaging revealed that after radiosurgery, tumor size had decreased in 17 cases (50%), was unchanged in 14 (41.2%), and had increased in three (8.8%). Local tumor control was achieved in 31 of 34 cases (91.2%). Objectively defined tumor shrinkage was seen within 3 to 24 (median, 12) months of treatment, the rate of shrinkage increasing with longer follow-up. Three to 16 (median, 6) months after treatment, loss of central tumor enhancement was evident in 28 cases(82.4%). In 25 of 28 patients with intratumoral necrosis (89.3%), tumors were either smaller of their size was unchanged. Three to six (mean, 3.6) months after treatment, five cases demonstrated a transient size increase. CONCLUSION: Gamma-knife radiosurgery effectively controlled the growth of acoustic schwannoma, and intra-tumoral necrosis appears to be a predictable sign for decreased tumor size.

MRI Findings of Temporal Lobe Ganglioglioma

PURPOSE: Ganglioglioma is a rare primary brain tumor usually found in the temporal lobe. The purpose of thisstudy is to describe the characteristic MR findings of temporal lobe ganglioglioma. MATERILA AND METHODS: Over aseven-year period, ten patients with cerebral ganglioglioma were evaluated at our institution. Seven cases oftemporal lobe ganglioma were found ; six of these involved men, and one, a woman ; their mean age was 29.6 years.In three patients, Gd-DTPA-enhanced T1 weighted images were also obtained. We retrospectively analysed the MRIfindings with respect to location, size, cortical involvement, margin, cystic change, degree of enhancement, MRsignal intensity, calcification and peritumoral change. RESULTS: In five cases, tumors were located within thetemporal lobe. In one, a tumor extended from the temporal lobe to the thalamus, and in one from the temporal lobeto the thalamus and cerebral peduncle. All temporal gangliogliomas measured 1.6-3.8cm in their greatestdiameter(mean diameter, 2.7cm). In all cases, the cortices were involved with the maintenance of gyriform. Thetumor margin was ill defined in five cases and well defined in two. Tumors showed multiple small cystic changes infour cases, a large cyst in two, and a solid nodule in one. In three cases in which contrast media wasadministered, no lesions were enhanced. On T1-weighted images, iso-signal intensities were seen in five cases andhigh signal intensities in two. On T2-weighted images, the corresponding figures were five and two. On MRI, tumorcalcification and calvarial erosion were each detected in two cases. CONCLUSION: In patients with temporal lobeepilepsy in whom cortical solid or cystic and poorly enhanced lesions were seen on brain MRI, and in whomaccociated findings such as calcification and or adjacent bony erosion were noted, ganglioglioma must beconsidered.

Desmoplastic Infantile Ganglioglioma: A Case Report

Desmoplastic infantile ganglioglioma is an uncommon variety of ganglioglioma that shows evidence of glial andganglionic differentiation accompanied by an extreme desmoplastic reaction. A 16-month-old girl was ad-mitted witha six-day history of left hemiparesis. MR imaging demonstrated a large multiseptated cystic mass, with a solidportion, in the white matter of the right frontotemporoparietal lobe. After contrast injections, the solid portionwas clearly enhanced. The presence of desmoplastic infantile ganglioglioma was confirmed by surgical resection. Wedescribe the characteristic radiologic and pathologic features of desmoplastic infantile ganglioglioma, andinclude a a review of the literature.

CT, MR and Angiographic Findings of Hemangiopericytomas

PURPOSE: Hemangiopericytoma(HP) exhibits its pathologic findings different from those of meningioma or oth-erangiomatous tumor; and its clinical behavior is unique and prognosis worse than other cases. We reviewed the CT,MR and angiographic findings of HPs and evaluated differential radiologic points of comparison be-tween typicalmeningiomas and meningeal HPs. MATERIALS AND METHODS: MR(n=16), CT(n=5) and angiographic imaging(n=10) wereperformed in 18 pa-tients(M:F=12:6, mean age:45 years) with histologically proven primary HPs. We evaluated theimaging find-ings of HPs with respect to site, shape, size, signal intensity, enhancement characteristics,vascular signal voids, calcification, bony and adjacent sinus involvement, and angiographic findings. RESULTS:HPs were meningeal in 14 cases and nonmeningeal in four. Meningeal HPs were located in the parasagittalregion(n=8), convexity(n=3), intradural extramedullary space(n=1), choroid plexus(n=1), and ol-factorygroove(n=1). Nonmeningeal HPs were located in the masticator space(n=2), paraspinal area(n=1) and supraclaviculararea(n=1). The mean maximal dimension of tumors was about 5.4cm and their shape was papillary(n=8) orlobulated(n=7). MR images showed high(n=13) or iso(n=3) signal intensities on T2WI, and heterogeneity onT2WI(n=9). Vascular signal voids in the mass were seen in all cases, while in two cases, CT scanning showednodular dense calcification. Bone destruction was present in six cases, but no hyperostosis was found. In fivecases, the superior sagittal sinus was involved. Angiographic images revealed highly vascu-lar masses supplied bythe internal carotid artery(n=5), external carotid artery(n=8), descending scapular artery(n=1) andradiculomedullary artery(n=1), with delayed tumor blush during the capillary and venous phase in which there wasno arteriovenous shunt. CONCLUSION: HP is one of the extra-axial tumors in which there is hypervascularity,aggressive bony destruc-tion arising in the meningeal and extrameningeal area, and heterogeneous high signalintensity, as seen on T2WI. Calcification is rare.

Desmoplastic Cerebral Astrocytoma of Infancy: A Case Report

Desmoplastic cerebral astrocytoma of infancy is a rare neoplasm with distinctive clinical and radiographicfeatures. Almost all cases present in the first two years of life as a large, supratentorial, enhancing mass witha peripheral dural-based solid component and a central cystic component. After complete surgical excision, thecourse of this tumor is benign, and adjuvant chemotherapy or radiation therapy may not be required. We describethe case of a 9-month-old boy with a desmoplastic cerebral astrocytoma of infancy and review the associatedliterature.

MR Imaging of the Meckel's Cave: Anatomy and Pathology

The Meckel's cave is a dural recess containing trigeminal nerve and ganglion, extending from the posterior fossa into the middle cranial fossa. Using MRI, internal architecture in the Meckel's cave can be discernible, even a small nodule within it can be detected. There are a wide spectrum of disease process occurring in and or in the vicinity of the Meckel's cave. Disease can be classified into pathology of the trigeminal nerve proper, within the trigeminal cistern and outside the trigeminmal cistern. These classification depending on the location will aid in interpretation of pathology of Meckel's cave. We will demonstrate the MR anatomy and various pathologies of the Meckel's cave.

MR Findings of Atypical Meningioma: Comparison with Benign Meningioma

PURPOSE: Atypical meningioma is an intermediate type, between benign and malignant meningiomas, and has ahigher recurrence rate and poorer prognosis than the benign type. The purpose of this study was to evaluate thedifferential imaging findings between atypical and benign meningiomas. MATERIALS AND METHODS: Over a five-yearperiod, 11 acses of atypical meningioma (in ten patients) were pathologically proven, and 30 benign meningiomaswere collected consecutively over 6 months. In retrospective analysis, the MR findings of atypical and benignmeningiomas were compared with respect to tumor respect to tumor margin, lobulation, intra-/peritumoralhemorrhage, cystic change, heterogeneity peritumoral edema, enhacement of adjacent meninges, invasion of adjacentvenous sinus and adjacent bony change. RESULTS: Significant differential MR findings between the two groups wereill-defined tumor margin(atypical-27%;benign-0%), lobulation(82%;43%), heterogeneity(73%;30%), and peritumoraledema(100%;47%). With regard to moderate edema, there was no significant difference between the twogroups(36%;23%), and with regard to intra-/peritumoral hemorrhage, cystic change, enhancement of adjacentmeninges, invasion of adjacent venous sinus, and adjacent bony change, MR findings between the two groups were notsignificantly different. CONCLUSION: The MR findings of atypical meningioma are significantly different inseveral ways from those of benign meningioma, and these differences may help differentiate the two types.