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Purpose It is difficult to differentiate CNS lymphoma from other tumors such as malignant gliomas, metastases, or meningiomas with conventional MR imaging, because the imaging findings are overlapped between these tumors. The purpose of this study is to investigate the perfusion weighted MR imaging findings of CNS lymphomas and to compare the relative cerebral blood volume ratios between CNS lymphomas and other tumors such as high grade gliomas, metastases, or meningiomas. Materials and methods We retrospectively reviewed MRI findings and clinical records in 13 patients with pathologically proven CNS lymphoma between January 2006 and November 2008. We evaluated the relative cerebral blood volume ratios of tumor, which were obtained by dividing the values obtained from the normal white matter on MRI. Results Total 13 patients (M:F = 8:5; age range 46–67 years, mean age 52.3 years) were included. The CNS lymphomas showed relatively low values of maximum relative CBV ratio in most patients regardless of primary or secondary CNS lymphoma. Conclusion Perfusion weighted image may be helpful in the diagnosis of CNS lymphoma in spite of primary or secondary or B cell or T cell.

The purpose of this study was to evaluate the signal intensity (SI) change of the labyrinth in patients with vestibular schwannoma on isotropic 3D fluid-attenuated inversion recovery (FLAIR) imaging at 3 T.Thirty-four patients with surgically confirmed or radiologically diagnosed vestibular schwannoma were included in this study. Retrospectively, we visually and quantitatively compared the SIs of the cochlea and vestibule on the affected side with those on the unaffected side. We also investigated whether there was correlation between the SI ratios (SIRs) of the labyrinth and the audiometric findings.On 3D FLAIR images, the SI of the cochlea and vestibule on the affected side was significantly increased in 97% (33/34) and 91% (31/34), respectively. While the SI of the cochlea was diffusely increased, that of the vestibule was only partially increased. Quantitative study also revealed statistically significantly higher SIRs of the cochlea (0.99 +/- 0.29) and vestibule (0.73 +/- 0.31) on the affected side, compared with the cochlea (0.47 +/- 0.20) and vestibule (0.19 +/- 0.10) on the unaffected side. There was no significant correlation of the SIRs of the labyrinth with the degree of hearing loss.In patients with vestibular schwannoma, isotropic 3D FLAIR imaging is a useful method for the evaluation of the SI changes of the labyrinth.

Purpose To evaluate the value of the high signal intensity halo sign as a new marker of a fresh or recent intraplaque hemorrhage on the maximum intensity projection (MIP) images of time-of-flight (TOF) MR angiography. Materials and Methods A total of 135 consecutive patients were included in this study. High-resolution MRI using 3-inch surface coils was performed on a 1.5T scanner before the carotid endarterectomy. TOF MR angiograms and T2-weighted, T1-weighted pre- and postcontrast fast spin echo images were obtained. The surgical and pathological findings of the carotid artery were analyzed and correlated with the MRI findings. Results A total of 42 atheromas (31.1%) had a fresh or recent intraplaque hemorrhage on the surgicopathological findings. A total of 38 (90.5%) of these patients showed high signal intensity halo around the carotid artery on the MIP images of TOF MR angiography. The high signal intensity halo sign, compared with the surgical and histopathological findings, demonstrated a sensitivity, specificity, positive predictive value, and negative predictive value of 91%, 83%, 72%, and 95%, respectively, with a 95% confidence interval (CI) in the detection of an intraplaque hemorrhage. The multisequence approach suggested the presence of an intraplaque hemorrhage with a sensitivity, specificity, positive predictive value, and negative predictive value of 93%, 85%, 74%, and 96%, respectively, with a 95% CI. Conclusion High signal intensity halo around the carotid artery on the MIP images of TOF MR angiography is useful in the noninvasive detection of a fresh or recent carotid intraplaque hemorrhage. J. Magn. Reson. Imaging 2008;27:1341–1346. © 2008 Wiley-Liss, Inc.

Aneurysms of the posterior cerebral artery (PCA) are rare, and most of the studies reported in the literature in which the endovascular approach was applied were carried out on a limited number of patients with PCA aneurysms. We retrospectively reviewed our cases of PCA aneurysms--at various locations and of differing shapes--that received endovascular treatment and evaluated the treatment outcome.From January 1996 to December 2006, 13 patients (eight females and five males) with 17 PCA aneurysms (nine fusiform and eight saccular) were treated using the endovascular approach. The age of the patients ranged from 20 to 67 years, with a mean age of 44 years. Of the 13 patients, ten presented with intracranial hemorrhage, and one patient, with a large P2 aneurysm, presented with trigeminal neuralgia; the aneurysms were asymptomatic in the remaining two patients.All 13 patients were successfully treated, with only one procedure-related symptomatic complication. Seven patients were treated by occlusion of the aneurysm and parent artery together; five patients, by selective embolization of the aneurysm; one patient, by partial coiling. Although infarctions were found in two patients treated with selective embolization and in three patients treated with parent artery occlusion, only one patient with a ruptured P2 aneurysm treated with parent artery occlusion developed transient amnesia as an ischemic symptom.Posterior cerebral artery aneurysms can be treated safely with either occlusion of the aneurysm together with the PCA or with a selective coil embolization. Infarctions may occur after endovascular treatment, but they are rarely the cause of a disabling symptom.

The aim of this study was to differentiate hemangioblastomas from metastatic brain tumors using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and compare the diagnostic performances with diffusion-weighted imaging (DWI) and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI). We retrospectively reviewed 7 patients with hemangioblastoma and 15 patients with metastatic adenocarcinoma with magnetic resonance imaging (MRI) including DWI, DSC-MRI, and DCE-MRI. Apparent diffusion coefficient (ADC), relative cerebral blood volume (rCBV), and DCE-MRI parameters (K trans, k ep, v e, and v p) were compared between the two groups. The diagnostic performance of each parameter was evaluated with receiver operating characteristic (ROC) curve analysis. v p, k ep, and rCBV were significantly different between patients with hemangioblastoma and those with metastatic brain tumor (p 0.012 showed 100 % sensitivity, 93.3 % specificity, and 95.5 % accuracy and a rCBV > 8.0 showed 85.7 % sensitivity, 93.3 % specificity, and 90.9 % accuracy for differentiating hemangioblastoma from metastatic brain tumor. DCE-MRI was useful for differentiating hemangioblastoma from metastatic brain tumor.

Objective Endovascular treatment using Onyx has been increasingly used to treat intracranial dural arteriovenous fistulas (DAVFs). This study evaluated predictive factors for favorable treatment outcome in patients with intracranial noncavernous DAVFs treated by transarterial Onyx embolization. Methods Between August 2008 and August 2014, 55 patients who underwent transarterial Onyx embolization for noncavernous DAVFs were retrospectively reviewed. Patients' demographic, clinical, and procedural data were analyzed to find statistically significant predictive factors for favorable treatment outcomes after Onyx embolization. Fistulas were classified angiographically according to the relationship between fistulas and dural venous sinuses and the presence of leptomeningeal venous reflux. Results Sixty-eight Onyx embolizations were performed in 55 patients. Immediate angiographic cure was achieved in 28 patients, and 14 of 27 patients with residual shunts showed progressive occlusion at follow-up imaging studies. Therefore, the overall favorable treatment outcome was 76.4% (42/55). The remaining 13 patients (23.6%) showed persistent residual shunts, and 3 (5.5%) of them showed aggravation of residual lesion on follow-up studies. Of 25 patients with non-sinus fistulas, 23 patients (92%) showed favorable treatment outcomes, and 19 of 30 patients (63.3%) with sinus fistulas showed favorable outcomes. Among the evaluated variables, non-sinus DAVFs was a statistically significant predictive factor for favorable response to transarterial Onyx embolization ( P Conclusions Transarterial Onyx embolization is a highly effective treatment method for non-sinus DAVFs. Careful consideration of angiographic features and multimodal embolization strategies are required for treatment of sinus DAVFs.

OBJECTIVE. The objective of our study was to assess the CT features of surgically resected pleomorphic carcinoma of the lung.CONCLUSION. The CT features of pleomorphic carcinoma of the lung appear to be dictated by the epithelial component of the tumor. Among the various subtypes of pleomorphic carcinoma, the large cell and giant cell subtype showed constant CT features including subpleural location, peritumoral areas of ground-glass attenuation, and extensive central low-attenuation areas.

Background Magnetic resonance imaging (MRI) is well accepted for the contemporary diagnosis of venous malformation (VM), providing hemodynamic and anatomic information on the lesion, including its relationship with surrounding tissues and organs. Study design A total of 196 clinically suspected VM patients were reviewed retrospectively to assess the accuracy and reliability of MRI for the diagnosis of VM. Initial workup included MRI, duplex ultrasonography, and whole-body blood pool scintigraphy, along with additional transarterial lung perfusion scintigraphy and lymphoscintigraphic assessment when indicated. Phlebography or arteriography, or both, were generally reserved as a road map for the treatment. A total of 294 MRI findings for 196 patients were also compared with the matching duplex ultrasonography findings available for 178 patients and matching whole-body blood pool scintigraphy findings for 136 patients. The phlebographic findings available for 87 patients were also compared. Results Among the 196 patients with clinically suspected VM, 174 were confirmed as having VM by MRI with true-positive findings and 2 as false-positive findings by MRI (sensitivity, 98.9%; positive predictive value, 98.9%). MRI ruled out VM for 18 patients with true-negative findings, though 2 were false-negative (specificity, 90%; negative predictive value, 90.0%). Two positive and two false-negative findings of VM, made by MRI, were subsequently confirmed by angiography. Among the 87 patients for whom phlebographic findings were available, 73 were confirmed as true-positive diagnoses of VM, 1 as false-positive, 11 as true-negative, and 2 as false-negative (sensitivity, 97.3%; specificity, 91.7%; positive predictive value, 98.7%; negative predictive value, 84.6%). Conclusions MRI is likely to modify the traditional role of angiography for the management of VM and become a new standard, at least for diagnosis. MRI also is an excellent parameter in the assessment of treatment results.

Objective: The differentiation between orbital lymphoma and subacute or chronic inflammatory pseudotumor (SCIPT) may be difficult clinically and radiologically. The aim of this study was to evaluate the enhancement characteristics of orbital lymphoma and SCIPT with two-phase helical computed tomography (CT) and delayed coronal CT and to determine whether attenuation measurements on CT can be used to differentiate between the 2 diseases. Methods: Nineteen histopathologically proven orbital lymphomas and 9 SCIPTs were examined with two-phase helical CT. After injecting 90 mL contrast material at a rate of 3 mL/s, early- and late-phase axial CT scans were obtained with scanning delays of 30 and 90 seconds, respectively. Delayed coronal scans were obtained with delays of 4-9 minutes. Attenuation of the lesions at each phase was measured quantitatively. Relative percentages of contrast enhancement (CE) were calculated to determine the cutoff value for differentiating SCIPT from lymphoma. Results: The CT attenuation change over time was significantly different between orbital lymphoma and SCIPT (P < 0.05). Increased CT attenuation between early- and late-phase axial scans was seen in 42% (n = 8) of lymphoma cases, and decreased CT attenuation was seen in 58% (n = 11). In 17 lymphomas (90%), the CT attenuation decreased between late-phase axial and delayed coronal scans. Conversely, in 7 SCIPTs (78%), the CT attenuation increased gradually over time from early-phase axial to delayed coronal scans. The relative percentage of CE at the delayed coronal scan had a cutoff value of -6.97%, a sensitivity of 84%, and a specificity of 100%. Conclusion: Different characteristics of attenuation change on two-phase helical CT and delayed coronal CT can be helpful in differentiating between orbital lymphoma and SCIPT.

The purpose of this study was to compare multiphasic perfusion computed tomography (CT) with diffusion and perfusion magnetic resonance imaging (MRI) in predicting final infarct volume, infarct growth, and clinical severity in patients with hyperacute ischemia untreated by thrombolytic therapy.Multiphasic perfusion CT was performed in 19 patients with ischemic stroke within 6 hours of symptom onset. Two CT maps of peak and total perfusion were generated from CT data. Diffusion-weighted imaging (DWI) and perfusion MRI were obtained within 150 minutes after CT. Lesion volumes on CT and MRI were compared with final infarct volume and clinical scores, and mismatch on CT or MRI was compared with infarct growth.The lesion volume on the CT total perfusion map strongly correlated with MRI relative cerebral blood volume (rCBV), and that on the CT peak perfusion map strongly correlated with MRI relative cerebral blood flow (rCBF) and rCBV (P0.001). The lesion volume on unenhanced CT or DWI moderately correlated with final infarct volume, but only lesion volume on unenhanced CT weakly correlated with baseline clinical scores (P = 0.024). The lesion volumes on the CT peak perfusion map and MRI rCBF similarly correlated with final infarct volume and clinical scores and more strongly than those on mean transit time (MTT) or time to peak (TTP). DWI-rCBF or CT mismatch was more predictive of infarct growth than DWI-MTT or DWI-TTP mismatch.Multiphasic perfusion CT is useful and of comparable utility to diffusion and perfusion MRI for predicting final infarct volume, infarct growth, and clinical severity in acute ischemic stroke.

Objective: To determine the utility of perfusion MR imaging in the differential diagnosis of brain tumors. Materials and Methods: Fifty-seven patients with pathologically proven brain tumors (21 high-grade gliomas, 8 low-grade gliomas, 8 lymphomas, 6 hemangioblastomas, 7 metastases, and 7 various other tumors) were included in this study. Relative cerebral blood volume (rCBV) and time-to-peak (TTP) ratios were quantitatively analyzed and the rCBV grade of each tumor was also visually assessed on an rCBV map. Results: The highest rCBV ratios were seen in hemangioblastomas, followed by high-grade gliomas, metastases, low-grade gliomas, and lymphomas. There was no significant difference in TTP ratios between each tumor group (p>0.05). At visual assessment, rCBV was high in 17 (81%) of 21 high-grade gliomas and in 4 (50%) of 8 low-grade gliomas. Hemangioblastomas showed the highest rCBV and lymphomas the lowest. Conclusion: Perfusion MR imaging may be helpful in the differentiation of thevarious solid tumors found in the brain, and in assessing the grade of the various glial tumors occurring there.

Objective To document the signal characteristics of intracerebral hemorrhage (ICH) at evolving stages on diffusion-weighted images (DWI) by comparison with conventional MR images. Materials and methods In our retrospective study, 38 patients with ICH underwent a set of imaging sequences that included DWI, T1-and T2-weighted imaging, and fluid-attenuated inversion recovery (FLAIR). In 33 and 10 patients, respectively, conventional and echo-planar T2* gradient-echo images were also obtained. According to the time interval between symptom onset and initial MRI, five stages were categorized: hyperacute (n=6); acute (n=7); early subacute (n=7); late subacute (n=10); and chronic (n=8). We investigated the signal intensity and apparent diffusion coefficient (ADC) of ICH and compared the signal intensities of hematomas at DWI and on conventional MR images. Results DWI showed that hematomas were hyperintense at the hyperacute and late subacute stages, and hypointense at the acute, early subacute and chronic stages. Invariably, focal hypointensity was observed within a hyperacute hematoma. At the hyperacute, acute and early subacute stages, hyperintense rims that corresponded with edema surrounding the hematoma were present. The mean ADC ratio was 0.73 at the hyperacute stage, 0.72 at the acute stage, 0.70 at the early subacute stage, 0.72 at the late subacute stage, and 2.56 at the chronic stage. Conclusion DWI showed that the signal intensity of an ICH may be related to both its ADC value and the magnetic susceptibility effect. In patients with acute stroke, an understanding of the characteristic features of ICH seen at DWI can be helpful in both the characterization of intracranial hemorrhagic lesions and the differentiation of hemorrhage from ischemia.

To evaluate the added value of diffusion-weighted imaging (DWI) to perfusion-weighted imaging (PWI) for differentiating tumour progression from radiation necrosis.Sixteen consecutive patients who underwent removal of a metastatic brain tumour that increased in size after stereotactic radiosurgery were retrospectively reviewed. The layering of the ADC was categorised into three patterns. ADC values were measured on each layer, and the maximum rCBV was measured. rCBV and the layering pattern of the ADC of radiation necrosis and tumour progression were compared.Nine cases of radiation necrosis and seven cases of tumour progression were pathologically confirmed. Radiation necrosis (88.9 % vs. 14.3 %) showed a three-layer pattern of ADC with a middle layer of minimum ADC more frequently. If rCBV larger than 2.6 was used to differentiate radiation necrosis and tumour progression, the sensitivity was 100 % but specificity was 56 %. If the lesions with the three-layer pattern of ADC with moderately increased rCBV (2.6-4.1) were excluded from tumour progression, the sensitivity and specificity increased to 100 %.The three-layer pattern of ADC shows high specificity in diagnosing radiation necrosis; therefore, combined analysis of the ADC pattern with rCBV may have added value in the correct differentiation of tumour progression from radiation necrosis.

Does dynamic gadolinium-enhanced imaging with simultaneous acquisition of coronal and sagittal planes improve diagnostic accuracy of pituitary microadenomas compared with coronal images alone?Fifty-six patients underwent 3-T sella MRI including dynamic simultaneous acquisition of coronal and sagittal planes after gadolinium injection. According to conspicuity, lesions were divided into four scores (0, no; 1, possible; 2, probable; 3, definite delayed enhancing lesion). Additional information on supplementary sagittal images compared with coronal ones was evaluated with a 4-point score (0, no; 1, possible; 2, probable; 3, definite additional information). Accuracy of tumour detection was calculated.Average scores for lesion detection of a combination of two planes, coronal, and sagittal images were 2.59, 2.32, and 2.18. 6/10 lesions negative on coronal images were detected on sagittal ones. Accuracy of a combination of two planes, of coronal and of sagittal images was 92.86%, 82.14% and 75%. Six patients had probable or definite additional information on supplementary sagittal images compared with coronal ones alone (10.71%).Dynamic MRI with combined coronal and sagittal planes was more accurate for detection of pituitary microadenomas than routinely used coronal images. Simultaneous dynamic enhanced acquisition can make study time fast and costs low.We present a new dynamic MRI technique for evaluating pituitary microadenomas • This technique provides simultaneous acquisition of contrast enhanced coronal and sagittal images. • This technique makes the diagnosis more accurate and reduces the examination time. • Such MR imaging only requires one single bolus of contrast agent.

To evaluate the neurovascular compression (NVC) in patients with trigeminal neuralgia (TN) using T2 VISTA and FLAIR VISTA fusion imaging. Sixty-six consecutive patients with TN who underwent MR imaging at 3-T between April 2008 and December 2010 were retrospectively reviewed. Multiplanar reconstructions (MPR) of T2 VISTA and FLAIR VISTA fusion imaging were used for image interpretation. The frequency of vascular contact, the segment of compression and the type of vessel were compared between the ipsilateral symptomatic side and the contralateral asymptomatic side. The frequency of vascular contact on the ipsilateral side and the contralateral side were 95.5% (63/66) and 74.2% (49/66), respectively. The frequency of indentation on the ipsilateral side and contralateral side were 74.2% (49/66) and 21.2% (14/66), and showed a statistically significant difference (p

Background: Oligodendrogliomas are primarily supratentorial tumors. However, infrequently, they can also arise from infratentorial structures. There are only limited numbers of radiological articles on the specific imaging findings of this entity. Purpose: To investigate the imaging findings of infratentorial oligodendrogliomas. Material and Methods: We retrospectively reviewed the magnetic resonance imaging (MRI) findings and clinical records of six patients with pathologically proven infratentorial oligodendrogliomas between December 1994 and April 2008. Tumor location, circumscription, signal intensity (SI), enhancement pattern, the presence of restricted diffusion, and the change of the relative cerebral blood volume (rCBV) on MRI were evaluated. Results: In total, six patients (three male, three female; mean age 65 years, range 51–75 years) were included. The pathology revealed anaplastic oligodendrogliomas in all six patients. The location was cerebellum in four patients, medulla in one patient, and fourth ventricle and tegmentum in one patient. Three of them were of the infiltrative type, and the other three of the mass-forming type. The solid component of the tumors showed high SI ( n=6) on FLAIR and T2-weighted images, and low ( n=5) or iso ( n=1) SI on T1-weighted images. All infiltrative lesions showed multifocal patchy enhancement, and mass-forming lesions showed heterogeneous enhancement ( n=2) and diffuse homogeneous enhancement ( n=1). Three patients had restricted diffusion, and one had leptomeningeal seeding. There was markedly increased rCBV on perfusion-weighted image (PWI) in one patient. Calcification or hemorrhage was not found. Tumor progression after operation, radiation therapy, gamma-knife surgery, or chemotherapy developed in five patients. Conclusion: Although infratentorial oligodendrogliomas did not show characteristic imaging findings, there was a tendency toward multifocal heterogeneous enhancement and absent or mild mass effect of infiltrative lesions. Infratentorial oligodendrogliomas may be more malignant than supratentorial oligodendrogliomas.

A 51-year-old female presented with bilateral accessory middle cerebral arteries (MCA) with associated ruptured aneurysm manifesting as a subarachnoid hemorrhage. Angiography demonstrated the bilateral accessory MCA and associated ruptured aneurysm at the junction of the left anterior cerebral artery and left accessory MCA. This was successfully treated by coil embolization. Magnetic resonance angiography obtained 6 months later revealed no evidence of residual or recurring aneurysm.

Sinonasal inverted papilloma (IP) is known for high rate of associated malignancy. The purpose of this study was to identify (18)F-FDG PET/CT findings of sinonasal IPs. We also tried to compare the PET/CT findings with the MR imaging findings.We retrospectively reviewed PET/CT and MR images of eight patients with sinonasal IP with (n = 6) or without (n = 2) coexistent squamous cell carcinoma (SCC). Particular attention was paid to correlate the PET/CT findings with the MR imaging findings in terms of area distribution of standard uptake values (SUVs) and a convoluted cerebriform pattern (CCP).In two benign IPs, the maximum SUVs measured 8.2 and 7.8, respectively (mean, 8.0). In both tumors, MR images demonstrated a diffuse CCP. In six IPs with coexistent SCC, the maximum SUVs ranged from 13.3 to 31.9 (mean +/- SD, 20.2 +/- 6.6). In these tumors, MR images demonstrated a diffuse CCP in two, a partial CCP in three, and no CCP in one. A wide discrepancy was noted between MR imaging and PET/CT in terms of area distribution of a CCP and SUVs.In sinonasal lesions with MR imaging features of IP, (18)F-FDG PET/CT demonstrating avid FDG uptake does not necessarily imply the presence of coexistent malignancy. In our small series, although IPs containing foci of SCC had consistently higher SUVs than IPs without SCC, the limited literature on this subject suggests that PET cannot be used reliably to make the distinction.

Radiosurgery is a noninvasive procedure where spatially accurate and highly conformal doses of radiation are targeted at brain lesions with an ablative intent. Recently, radiosurgery has been established as an effective technique for local treatment of brain metastasis. After radiosurgery, magnetic resonance (MR) imaging plays an important role in the assessment of the therapeutic response and of any complications. The therapeutic approach depends on the imaging findings obtained after radiosurgery, which have a role in the decision making to perform additional invasive modalities (repeat resection, biopsy) to obtain a definite diagnosis and to improve the survival of patients. Conventional MR imaging findings are mainly based on morphological alterations of tumors. However, there are variable imaging findings of radiation-induced changes including radiation necrosis in the brain. Radiologists are sometimes confused by radiation-induced injuries, including radiation necrosis, that are seen on conventional MR imaging. The pattern of abnormal enhancement on follow-up conventional MR imaging closely mimics that of a recurrent brain metastasis. So, classifying newly developed abnormal enhancing lesions in follow-up of treated brain metastasis with correct diagnosis is one of the key goals in neuro-oncologic imaging. To overcome limitations of the use of morphology-based conventional MR imaging, several physiological-based functional MR imaging methods have been used, namely diffusion-weighted imaging, perfusion MR imaging, and proton MR spectroscopy, for the detection of hemodynamic, metabolic, and cellular alterations. These imaging modalities provide additional information to allow clinicians to make proper decisions regarding patient treatment.

Objective HydroCoil (MicroVention, Aliso Viejo, CA), a hydrogel-platinum coil hybrid device, is one of various efforts to overcome delayed recanalization of coiled intracranial aneurysms. The purpose of this study was to investigate the outcome of intracranial aneurysms treated with HydroCoils. Methods This multicenter prospective study included 80 aneurysms in 76 patients treated with HydroCoils. There were 32 (40%) ruptured and 48 (60%) unruptured aneurysms; 22 (28%) were large aneurysms (maximal diameter, > or = 10 mm) and 58 (72%) were small. Aneurysm volumes were 100 mm3 or more in 48 (60%) and less than 100 mm3 in 32 (40%); in 13 aneurysms (16%), volumes were 600 mm3 or more. Efficacy and safety were evaluated on the basis of degree of initial occlusion, procedure-related complications, and the follow-up result. Results Initial aneurysmal occlusion was complete in 60 (75%) aneurysms and near-complete in 14 (17.5%). Procedure-related complications included aseptic meningitis-related problems, including delayed hydrocephalus in 13 patients (28% among cases of unruptured aneurysms) and thromboembolism in two patients. Radiological follow-up data obtained 6 months or more after coil embolization were available in 54 aneurysms (68%) and revealed stable occlusion in 48 (89%) aneurysms, minor recanalization in one (2%), and major recanalization in five (9%). All of the recanalized aneurysms were 600 mm3 or more in volume, and aneurysm volume was a single important variable related to delayed recanalization on multiple logistic regression analysis (P = 0.016). Conclusion HydroCoil embolization seems to be a feasible treatment option in intracranial aneurysms in terms of initial aneurysmal occlusion rate and durability at the time of the follow-up evaluation; however, caution is required regarding aseptic meningitis and delayed hydrocephalus. Calculated aneurysmal volume of 600 mm3 seems to be critical in determining the anatomic outcome in aneurysms embolized with HydroCoils.

For extracranial arteriovenous malformations of the head and neck (HNAVMs), in which the nidus was accessible via the percutaneous route, ethanol sclerotherapy was a feasible and safe first-line treatment, although successful outcomes were obtained for only about half of the subjects. For other HNAVMs, surgical excision with embolization may be the best choice of treatment.To suggest a treatment protocol for patients with HNAVMs by comparing the treatment outcomes and complications of ethanol sclerotherapy with those of surgical excision combined with embolization.Twenty patients who had been diagnosed with HNAVM and treated between 1995 and 2002 were retrospectively reviewed. Ethanol sclerotherapy, surgical excision and embolization were used as treatments, either alone or in various combinations. The treatment outcomes and complications with the different modalities were analyzed.Ethanol sclerotherapy was used for 12 cases, with a success rate of 50.0% and a permanent complication rate of 8.3%. Surgical excision combined with embolization was used for 13 patients. Although all patients achieved successful resolution of their HNAVM after surgical excision, 15.4% suffered from permanent complications. In total, 16/20 patients (80.0%) eventually achieved aor = 75% reduction in the size of their lesions.

Objective: The aim of this study was to investigate the relationship between the diffusion and perfusion parameters in hyperacute infarction, and we wanted to determine the viability threshold for the ischemic penumbra using diffusion- and perfusion-weighted imaging (DWI and PWI, respectively). Materials and Methods: Both DWI and PWI were performed within six hours from the onset of symptoms for 12 patients who had suffered from acute stroke. Three regions of interest (ROIs) were identified: ROI 1 was the initial lesion on DWI; ROI 2 was the DWI/PWI mismatch area (the penumbra) that progressed onward to the infarct; and ROI 3 was the mismatch area that recovered to normal on the follow-up scans. The ratios of apparent diffusion coefficient (ADC), the relative cerebral blood volume (rCBV), and the time to peak (TTP) were calculated as the lesions’ ROIs divided by the contralateral mirror ROIs, and these values were then correlated with each other. The viability threshold was determined by using the receiver operating characteristic (ROC) curves. Results: For all three ROIs, the ADC ratios had significant linear correlation with the TTP ratios (p < 0.001), but not with the rCBV ratios (p = 0.280). There was no significant difference for the ADC and rCBV ratios within the ROIs. The mean TTP ratio/TTP delay between the penumbras’ two ROIs showed a significant statistical difference (p < 0.001). The cutoff value between ROI 2 and ROI 3, as the viability threshold, was a TTP ratio of 1.29 (with a sensitivity and specificity of 86% and 73%, respectively) and a TTP delay of 7.8 sec (with a sensitivity and specificity of 84% and 72%, respectively). Conclusion: Determining the viability thresholds for the TTP ratio/delay on the PWI may be helpful for selecting those patients who would benefit from the various therapeutic interventions that can be used during the acute phase of ischemic stroke.

Objective To describe the radiologic findings of primary peripheral T-cell lymphoma (PTCL) of the face other than mycosis fungoides. Methods Computed tomography (CT) and magnetic resonance imaging (MRI) findings of 5 consecutive patients with pathologically proven primary facial PTCL other than mycosis fungoides were retrospectively evaluated. Patients with PTCL involving the sinonasal cavity or lymph nodes were excluded. Results Diagnoses of patients included in this study consisted of natural killer/T-cell lymphoma (n = 2), subcutaneous panniculitis-like T-cell lymphoma (n = 1), anaplastic large cell lymphoma (n = 1), and PTCL not otherwise specified (n = 1). Infiltration or swelling of the superficial space of the face was noted on both CT and MRI, mimicking inflammation or infection. Also seen were well-enhancing small nodular (n = 2) or infiltrative mass-like lesions (n = 2) within the areas of infiltration, which showed intermediate signal intensity on T2-weighted images. One patient demonstrated infiltration and swelling alone. Conclusions Primary facial PTCL is a rarely encountered tumor and demonstrates infiltration or swelling mimicking inflammation or infection. Nodular or infiltrative mass-like lesions may be helpful for its diagnosis.

Objective: To assess the utility of multiphasic perfusion CT in the prediction of final infarct volume, and the relationship between lesion volume revealed by CT imaging and clinical outcome in acute ischemic stroke patients who have not undergone thrombolytic therapy. Materials and Methods: Thirty-five patients underwent multiphasic perfusion CT within six hours of stroke onset. After baseline unenhanced helical CT scanning, contrast-enhanced CT scans were obtained 20, 34, 48, and 62 secs after the injection of 90 mL contrast medium at a rate of 3 mL/sec. CT peak and total perfusion maps were obtained from serial CT images, and the initial lesion volumes revealed by CT were compared with final infarct volumes and clinical scores. Results: Overall, the lesion volumes seen on CT peak perfusion maps correlated most strongly with final infarct volumes (R 2 =0.819, p

Objective To evaluate the usefulness of triphasic perfusion computed tomography (TPCT) in diagnosing middle cerebral artery (MCA) occlusion and in assessing the perfusion deficit and collateral circulation in patients with acute ischemic stroke. Background Conventional angiography is the criterion standard for the diagnosis of MCA occlusion and for the assessment of perfusion deficit and collateral blood supply. The risk of hemorrhagic transformation after recanalization of occluded arteries by thrombolytic therapy is considered high when pretherapeutic residual flow is markedly reduced. Patients and Methods In 8 patients within 3 hours of onset of acute MCA stroke, precontrast computed tomographic scans were taken, and then TPCT was performed after power-injector controlled intravenous administration of contrast media. Sequential images of early, middle, and late phases were obtained. The whole procedure took 5 minutes. Perfusion deficit on TPCT was graded as "severe" or "moderate," depending on the state of collateral flow. Digital subtraction angiography (DSA) was performed in all patients within 6 hours of acute stroke. Direct intra-arterial urokinase infusion was begun immediately after the angiographic superselection of the MCA occlusion site in 6 of the 8 patients within 7 hours of onset (range, 4.3-6.2 hours). Results The DSA findings showed occlusion of the MCA stem (n = 1) and at the bifurcation (n = 4). The sites of proximal MCA occlusion could be identified on the early and middle images of TPCT in all 5 patients. On DSA findings, all 8 patients had a zone of perfusion deficit with markedly slow leptomeningeal collaterals and a zone of perfusion deficit with no collaterals. The zone of severe perfusion deficit on TPCT corresponded to the zone of perfusion deficit with no or few collaterals on angiography, and the zone of moderate perfusion deficit on TPCT corresponded to that of perfusion deficit with markedly slow leptomeningeal collaterals. Early parenchymal hypoattenuation on precontrast computed tomography was confined to the zone of severe perfusion deficit on TPCT. The initial National Institutes of Health Stroke Scale score correlated better with the total extent of severe perfusion deficit and moderate perfusion deficit on TPCT than that of severe perfusion deficit alone. After direct intra-arterial thrombolysis within 7 hours of onset, symptomatic hemorrhagic transformation did not develop in 4 patients with small severe perfusion deficit (33% or less of the presumed MCA territory). However, the remaining 2 patients with large severe perfusion deficit (more than 50% of the presumed MCA territory) deteriorated to death with hemorrhagic transformation. Conclusions Triphasic perfusion computed tomography is useful for diagnosing proximal MCA occlusion and assessing perfusion deficit and collateral circulation as reliably as DSA. The zone of severe perfusion deficit on TPCT may be presumed to be the ischemic core, and that of moderate perfusion deficit, the penumbra zone. Triphasic perfusion computed tomography may be used as a rapid and noninvasive tool to make thrombolysis safer.

To evaluate two-phase helical computed tomography (CT) in the characterization of salivary gland tumors.Sixty-four patients with major salivary gland tumors underwent two-phase helical CT. The histopathologic diagnosis was obtained by means of surgical resection or biopsy in all patients. After the injection of 90 mL of contrast material at a rate of 3 mL/sec, helical CT scans were obtained at early and delayed phases with scanning delays of 30 and 120 seconds, respectively. The attenuation change and enhancement patterns in the tumors were assessed. The attenuation change in the tumor also was assessed quantitatively as the ratio of the CT number (in Hounsfield units) at delayed phase scanning to that at early phase scanning.There were 35 pleomorphic adenomas, nine Warthin tumors, and 20 malignant tumors. Two-phase helical CT showed increase in attenuation in 30 (86%) pleomorphic adenomas, decrease in eight (89%) Warthin tumors, and increase in 11 (55%) and no change in eight (40%) malignant tumors at delayed phase scanning. A multinodular enhancement pattern was found in only 12 (34%) pleomorphic adenomas. The ratio of CT numbers was significantly different between Warthin tumors and pleomorphic adenomas and between Warthin tumors and malignant tumors.The analysis of enhancement patterns by using two-phase helical CT will be helpful in the differential diagnosis of salivary gland tumors.

Our purpose was to evaluate the usefulness of MR angiography in revealing moyamoya disease before and after encephaloduroarteriosynangiosis.Twenty-six patients (51 hemispheres) with angiographically confirmed moyamoya disease who underwent encephaloduroarteriosynangiosis were included in the study. Findings on preoperative MR angiography were compared with those on conventional angiography. Postoperative neurologic status was categorized as poor, fair, good, or excellent. Postoperative MR angiography was examined for the appearance of the superficial temporal artery, changes in moyamoya vessels, and transdural collateral vessels into the middle cerebral artery territory.Preoperative MR angiography revealed moyamoya disease in all patients (diagnostic accuracy, 100%). MR angiography correctly depicted the degree of internal carotid artery stenosis in 37 arteries (73%), moyamoya vessels in 33 hemispheres (65%), and the degree of stenosis in the middle, anterior, and posterior cerebral arteries in 125 (82%) of 153 arteries. After surgery, 39 hemispheres showed an excellent outcome, eight showed a good outcome, two a fair outcome, and two a poor outcome. On postoperative MR angiography, vascular supply to the middle cerebral artery territory via transdural collateral vessels increased in 28 hemispheres (55%) and decreased in four (8%). The size of the superficial temporal artery increased in 41 (80%) of 51 hemispheres. The extent of moyamoya vessels decreased in 27 hemispheres (53%) after surgery.MR angiography can show the changes in the superficial temporal artery and development of transdural collateral vessels after encephaloduroarteriosynangiosis. Because MR angiography is noninvasive, it is valuable for evaluating postoperative changes.

The purpose of this study was to evaluate the usefulness of color Doppler sonography in differentiating benign from malignant cervical lymphadenopathy.We used color Doppler sonography to evaluate 117 lymph nodes in 105 patients. The patients were pathologically and clinically confirmed to have benign reactive lymphadenitis (n = 28), tuberculosis (n = 17), lymphoma (n = 14), and metastasis (n = 46). The patterns of hilar vascularity, central nodal vascularity, and peripheral vascularity were assessed. The highest resistive index and pulsatility index in 116 lymph nodes were measured from spectral waveforms. Histologic findings of nodal vessels were analyzed in 14 nodes and compared with findings on color Doppler sonograms.Thirty-two (94%) of 34 nodes with benign reactive disease showed normal patterns of nodal vascularity; central hilar vascularity, radial symmetric central vascularity, and no peripheral vascularity. At least one of six abnormal patterns of vascularity (eccentric or absent hilar vascularity; deformed radial, aberrant multifocal, or absent central vascularity; and peripheral vascularity) was observed in 98% (65/66) of nodes with malignant disease and in all tuberculous nodes. We established cutoff values of 0.8 for the resistive index and 1.5 for the pulsatility index that were 100% specific for malignancy. However, sensitivities for these cutoff values were 47% and 55%, respectively. Also, histologic examinations showed that most flow signals in nodes with malignant disease represented arterioles or veins in the septa between tumor nests or near the capsule.Unlike nodes with benign reactive disease, 98% of nodes with malignant disease and 100% of tuberculous nodes showed abnormal patterns of nodal vascularity. Also, high values for the resistive and pulsatility indexes were highly specific for malignant lymphadenopathy. Color Doppler sonography combined with analysis of spectral waveforms was useful in differentiating benign from malignant cervical lymphadenopathy.

Objective We investigated low dose digital tomosynthesis (DT) for the evaluation of the paranasal sinus (PNS), and compared its diagnostic accuracy with a PNS radiography series (XR). Materials and Methods We enrolled 43 patients for whom XR, PNS DT, and OMU CT were performed. We measured effective doses (EDs) of XR, DT, and OMU CT using Monte Carlo simulation software. Two radiologists performed independent observation of both XR and DT. For seven PNSs, they scored anatomic conspicuity of sinuses and confidence on the presence of sinusitis using nine point scales. OMU CT was observed by the third radiologist and the findings were regarded as reference standard. We compared scores for conspicuity and sinusitis confidence between XR and DT. Results Mean EDs were 29 ± 6 µSv, 48 ± 10 µSv, and 980 ± 250 µSv, respectively, for XR, DT, and CT. Mean scores for conspicuity were 6.3 and 7.4, respectively, for XR and DT. Sensitivity per patient basis for sinusitis detection were 52% and 96%, respectively, for XR and DT in observer 1 (p = 0.001) and 80% and 92% for observer 2 (p = 0.25). Specificities for sinusitis exclusion were 100% for both XR and DT for observer 1 and 89% and 100% for observer 2 (p = 0.50). Accuracies for sinusitis diagnosis were 72% and 98%, respectively, for XR and DT for observer 1 (p = 0.001) and 84% and 95% for observer 2 (p = 0.125). Conclusion Patient radiation dose from low dose DT is comparable with that of PNS XR. Diagnostic sensitivity of DT for sinusitis was superior to PNS XR.

Objective: We aimed to evaluate the results of endovascular coil embolization for very small aneurysms ( 3 mm). Materials and Methods: Between March 2005 and December 2008, a total of 31 very small aneurysms in 30 patients were treated by coil embolization. Of the 31 aneurysms, five (16%) were ruptured, as opposed to 26 (84%) that were not. We assessed the procedural complications, immediate angiographic outcome after coiling, clinical outcome, and follow-up MR angiography (MRA). Results: Two thromboembolic complications occurred during the procedure, but did not lead to any persistent neurologic deficit. No procedural aneurysmal rupture was observed and procedure-related morbidity and mortality were both 0%. Occlusion was adequate in 25 aneurysms (81%) and incomplete in six aneurysms (19%). The clinical outcomes of five patients with ruptured aneurysms were good (Glasgow outcome scale 4), with no bleeding of the treated aneurysms during a mean follow-up period of 13.3 months. On 27 follow-up MRA, there was no recurrence, and the five incompletely occluded aneurysms showed a spontaneous amelioration resulting in an adequate occlusion. Conclusion: Coil embolization of very small aneurysms is technically feasible with good results. The long-term efficacy and the potential as a standard treatment strategy remain to be determined by randomized large trials.

Objective: The aim of this study was to examine the incidence of ischemia during protected carotid artery stenting (CAS) as well as to compare the protective efficacy of the balloon and filter devices on diffusion-weighted MR imaging (DWI). Materials and Methods: Seventy-one consecutive protected CAS procedures in 70 patients with a severe (> 70%) or symptomatic moderate (> 50%) carotid artery stenosis were examined. A balloon device (PercuSurge GuardWire) and a filter device (FilterWire EX/EZ, Emboshield) was used in 33 cases (CAS-B group) and 38 cases (CAS-F group) to prevent distal embolization, respectively. All the patients underwent DWI within seven days before and after the procedures. The number of new cerebral ischemic lesions on the post-procedural DWI were counted and divided into ipsilateral and contralateral lesions according to the relationship with the stenting side. Results: New cerebral ischemic lesions were detected in 13 (39.4%) out of the 33 CAS-Bs and in 15 (39.5%) out of the 38 CAS-Fs. The mean number of total, ipsilateral and contralateral new cerebral ischemic lesion was 2.39, 1.67 and 0.73 in the CAS-B group and 2.11, 1.32 and 0.79 in the CAS-F group, respectively. No statistical differences were found between the two groups (p = 0.96, 0.74 and 0.65, respectively). The embolic complications encountered included two retinal infarctions and one hemiparesis in the CAS-B group (9.09%), and one retinal infarction, one hemiparesis and one ataxia in the CAS-F group (7.89%). There was a similar incidence of embolic complications in the two groups (p = 1.00). Conclusion: The type of distal protection device used such as a balloon and filter does not affect the incidence of cerebral embolization after protected CAS.

To evaluate the use of multiphasic helical computed tomography (CT) in predicting subsequent development of severe brain edema in patients with acute middle cerebral artery (MCA) stroke.Case-control study.Tertiary referral hospital.We studied 31 patients with acute MCA stroke who had a baseline National Institutes of Health Stroke Scale score of 15 or higher within 6 hours of symptom onset. Sequential 4-phasic enhanced helical CT scans were performed after taking precontrast CT scans. The severity of perfusion deficit was graded as "severe" or "moderate" depending on collateral blood flow.Patients were classified as having severe brain edema if they showed signs of uncal herniation or deterioration with mass effect leading to hemicraniectomy.Severe brain edema developed in 10 patients (32%). Severe perfusion deficit greater than 50% of the presumed MCA territory on multiphasic helical CT was more often found in patients with severe brain edema than in those without (8 of 10 vs 4 of 21, P =.002). In contrast, parenchymal hypodensity greater than 50% on precontrast CT was observed only in 5 patients with severe brain edema (5 of 10 vs 4 of 21, P =.10). Additional involvement of the anterior or posterior cerebral artery territory was found on multiphasic CT (6 of 10 vs 0 of 21, P.001) and on precontrast CT (4 of 10 vs 0 of 21, P =.007) only in patients with severe brain edema.Multiphasic helical CT is more useful than precontrast CT for predicting subsequent severe brain edema in acute MCA stroke based on the findings of severe perfusion deficit greater than 50% of the MCA territory and additional involvement of the anterior or posterior cerebral artery territory.

Objectives To evaluate the frequency of intracranial atherosclerosis among patients with steno-occlusive extracranial carotid artery disease and to determine if there are factors related to the combined intracranial atherosclerosis. Design Cross-sectional study. Setting A tertiary referral hospital. Patients We studied 142 consecutive patients who had atherosclerotic steno-occlusive lesions (defined as ≥30% narrowing of the luminal diameter or occlusion) of an extracranial carotid artery confirmed by conventional angiography. We excluded patients who had potential cardiogenic sources of embolism. Potential vascular risk factors for each patient were obtained from medical records. Main Outcome Measure We determined the location and severity of atherosclerotic lesions by conventional angiography. We compared the vascular risk factors between patients with steno-occlusive extracranial carotid artery disease alone and patients with combined intracranial atherosclerosis and extracranial carotid artery disease. Results Intracranial steno-occlusive lesions (≥30% stenosis or occlusion) were found in 80 patients (56.3%). Of 121 patients with significant (≥50% stenosis or occlusion) extracranial carotid artery disease, 58 (47.9%) also had significant lesions of intracranial arteries. Univariate and multivariate analyses showed that diabetes mellitus was the only significant factor associated with combined intracranial atherosclerosis in patients with extracranial carotid artery disease. Conclusions Intracranial atherosclerosis is common in Korean patients with steno-occlusive extracranial carotid artery disease. Diabetes mellitus is associated with intracranial atherosclerosis in patients who had steno-occlusive extracranial carotid artery disease.

Purpose: To assess the enhancement patterns of sellar and parasellar tumors at two-phase helical CT. Materials and Methods: Thirty-two patients with pathologically proven sellar and parasellar tumors [meningioma (n=17), pituitary mocroadenoma (n=6), neurogenic tumor (n=5), cavernous angioma (n=1), chondrosarcoma (n=1), osteosarcoma (n=1), sphenoid carcinoma (n=1)] were included in this study. Two-phase helical CT was performed after the injection of 90 mL of contrast material at a rate of 3 mL/sec. Transverse helical CT scans were obtained during the early and late phases, with scanning delays of 30 and 120 seconds, respectively. Delayed coronal images were obtained after delayed axial images. Attenuation change and the enhancement patterns of the tumors were visually assessed; the former was also assessed quantitatively as the ratio of the CT number at late-phase axial and coronal scanning to that at early-phase scanning. Results: Visual assessment of two-phase helical CT images revealed decreased attenuation in all 17 meningiomas, no change in all six pituitary macroadenomas and increased attenuation in 5 all five neurogenic tumors on late-phase axial scans as compared with early phase scans. Coronal images showed decreased attenuation in all 17 meningiomas, increased attenuation in all five neurogenic tumors and no change in four pituitary macroadenomas (66.7%). The ratio of CT numbers was significantly different between meningiomas, neurogenic tumors and pituitary macroadenomas(p

PURPOSE: To evaluate the usefulness of diffusion-weighted imaging after intracranial surgery in patients with intracranial tumors. MATERIALS AND METHODS: Within ten days of intracranial surgery, diffusion-weighted MR images were obtained in 68 patients with intracranial tumors which included meningioma (n=31), glioma (n=21), neurogenic tumor(n=4), hemangiopericytoma (n=3), and in three cases involved metastasis. The signal intensity of the resected margin and adjacent parenchyma was visually assessed on diffusion-weighted images, and the signal intensities on seen T1-and T2-weighted images were also analyzed. In patients with newly developed hyperintense lesions in parenchyma adjacent to the resection sites seen on postoperative T2-weighted images, apparent diffusion coefficients (ADC) were calculated and analyzed on follow-up MR images. RESULTS: Immediate postoperative diffusion-weighted images showed various signal intensities at the resected margins visible on conventional and diffusion-weighted MR images. In 15 patients, newly developed hyperintense lesions adjacent to resected sites were seen on postoperative T2-weighted images. On diffusion-weighted images, nine of these lesions were hyperinteuse and and were shown by follow-up MR imaging to be subject to focal tissue loss and atrophy, and six were isointense but with no sign of tissue loss or atrophy. Among the 15 patients with postoperative lesions near the site of tumorectomy, diffusion-weighted imaging showed that the ADC values of hyperintense lesions were significantly lower than those of isointense lesions (independent sample t-test: p

Purpose: To compare the diagnostic efficacy of fast spin-echo (FSE) T2-weighted MR imaging with and with-out fat suppression. Materials and Methods: Twelve patients (7 men and 5 women; mean age, 48 years) with pathologically proven cancer of the tongue were included in this study. In all of these, FSE T2-weighted MR images with and without fat suppression were obtained in the same imaging planes before surgery or biopsy. Two radiologists visually compared the images thus obtained in terms of detection, extent, and conspicuity of the tumor, and the con-trast-to-noise ratio (CNR) of each tumor was also calculated. Results: In all patients, both imaging modalities were equal in terms of tumor detection. In 4 of 12(33%), the extent of the tumor was greater with fat suppression, while in eight (67%), it was almost the same both with and without. In ten patients (83%), the tumor was more conspicuous with fat suppression, and percentage CNRs were significantly higher with fat suppression than without (180 70% and 113 61%, respectively; p = 0.02). Conclusion: For the evaluation of patients with tongue cancer, fat-suppressed FSE T2-weighted MR imaging is superior to its conventional equivalent.

Purpose: To assess the feasibility of contrast-enhanced fast fluid-attenuated inversion recovery (fast FLAIR) MR imaging in patients with brain tumors. Materials and Methods: This study involved 31 patients with pathologically proven brain tumors and nine with clinically diagnosed metastases. In all patients, T2-weighted, fast FLAIR, contrast-enhanced fast FLAIR and contrast-enhanced T1-weighted MR images were obtained. Contrast-enhanced fast FLAIR images were visually compared with other MR sequences in terms of tumor conspicuity. In order to distinguish tumor and sur-rounding edema, contrast-enhanced fast FLAIR images were compared with fast FLAIR and T2-weighted im-ages. The tumor-to- white matter contrast-to-noise ratios (CNRs), as demonstrated by T2-weighted, fast FLAIR, contrast-enhanced fast FLAIR and contrast-enhanced T1-weighted imaging, were quantitatively assessed and compared. Results: For the visual assessment of tumor conspicuity, contrast-enhanced fast FLAIR image imaging superi-or to fast FLAIR in 60% of cases (24/40), and superior to T2-weighted in 70% (28/40). Contrast-enhanced fast FLAIR imaging was inferior to contrast-enhanced T1-weighted in 58% of cases (23/40). For distinguishing between tumor and surrounding edema, contrast-enhanced fast FLAIR imaging was superior to fast FLAIR or T2-weighted in 22 of 27 tumors with peritumoral edema (81%). Quantitatively, CNR was the highest on con-trast-enhanced fast FLAIR image and the lowest on fast FLAIR. For the detection of leptomeningeal metas-tases, contrast-enhanced fast FLAIR was partially superior to contrast-enhanced T1-weighted imaging in two of three high-grade gliomas. Conclusion: Although contrast-enhanced fast FLAIR imaging should not be seen as a replacement for conventional modalities, it provides additional information for assessment of the extent of glial cell tumors and lep-tomeningeal metastases in patients with brain tumors.

Purpose: The purpose of this study was to determine the diagnostic value of a sign of early enhancing superior ophthalmic vein (SOV), as seen on helical CT images in patients with carotid-cavernous fistula (CCF). Materials and Methods: This study involved 16 patients with CCF and 28 control patients. Axial CT images with scanning delays of 30 seconds following bolus injection of contrast material (90 mL, 3 mL/sec) were ob-tained, and this procedure was followed by coronal CT imaging. To determine the presence or absence of ear-ly enhancement or, dilatation of the SOV, bulging of the cavernous sinus, and enlargement of extraocular muscle, CT images were analysed by three observers in a blinded, random manner. Early enhancement of SOV was determined to be present where enhancement of the SOV was similar to or stronger than that of the ipsi-lateral posterior cerebral artery. Results: A sign of early enhancing SOV was seen in 14 of the 16 patients with CCF but in no control patients (88% sensitivity and 100% specificity). The respective sensitivity and specificity of other CT features were 71% and 100% (dilatation of the SOV, as seen on axial images), 60% and 83% (dilatation of the SOV, as seen on coronal images), 71% and 89% (dilatation of the cavernous sinus), and 65% and 98% (enlargement of extraocu-lar muscle). Conclusion: A sign of early enhancing SOV is a characteristic and specific CT finding of CCF, and is useful for the diagnosis of CCF.

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.

Purpose : To determine the accuracy of three-dimensional CT angiography(CTA) in the diagnosis of intracranialaneurysms. Materials and Methods : 3D-CTA was performed in 46 consecutive patients with subarachnoid hemorrhage orsuspected intracranial aneurysm. Images were obtained using a helical CT scanner and the SSD techinque. 3D CTAfindings were reviewed retrospectively and independently in blind fashion by two neuroradiologists. Digitalsubtraction angiography(DSA) was used as the reference standard. Results : DSA revealed, in 36 patients, 40aneurysms ranging from 2mm to 12mm in maximal diameter, and negative findings in 10 patients. For observer 1, theaccuracy of 3D-CTA for all aneurysms and all patients was 85.2% and 82.7%, respectively. For observer 2, therespective figures were 94.6% and 91.9%. The agreement rates between the two observers were 86% for all aneurysmsand 87% for all patients (Kappa value 0.58, 0.59). Conclusion : Three-dimensional CTA is a useful imagingtechnique for the diagnosis of intracranial aneurysms, with an accuracy of over 85%

Purpose : To evaluate the preliminary results of endovascular coil treatment of acutely ruptured aneurysms.Materials and Methods : Between August 1995 and December 1997, 18 patients with 20 ruptured aneurysms weretreated. They were classified as Hunt and Hess grade I (n=3), grade II (n=1), grade III (n=3), grade IV (n=10) orgrade V (n=1). Endovascular treatment was performed at mean 5.2 (range, 1-18) days. The first aneurysm was treatedwith mechanical detachable spirals (MDS) and the others with Guglielmi detachable coils (GDC). Aneurysm size wascategorized as small (n=17) or large (n=3). Ten aneurysms were located in the anterior circulation, and ten in theposterior circulation. Using the Glasgow outcome scale (GOS), clinical outcome was evaluated 5 to 27 months aftertreatment in 11 patients. Three patients had already died. Results : In 14 of the 18 patients (16 of 20 aneurysms: 80%), treatment was successful. Four aneurysms failed due to unsuccessful catheter placement (n=2), smallaneurysm (n=1) or occlusion of the parent vessel (n=1). Total occlusion was observed in 13 aneurysms; 95-99%, orsubtotal occlusion, in two, and less than 95%, or in-complete occlusion, in one. Technical complications includedpassing of wire (n=1) and unintentional parent artery occlusion (n=1). There was a 7.1%(1/14) morbidity rate, butno mortality related to the technique. Six patients with Hunt and Hess grade I-III had good clinical outcome (3with GOS 1, and 2 with GOS 2). Four of the nine patients who were grade IV-V showed clinical improvement (GOS 3);two patients were clinically un-changed (GOS 4), and three died from the severity of primary hemorrhage.Conclusion : Endovascular coil treatment is a reasonable alternative for patients who are not candidates forconventional surgical treatment or in whom such treatment has failed.

Purpose : This study was performed in order to compare unenhanced CT with diffusion-weighted, T2-weight-ed,and fast FLAIR MR imaging in the detection of hyperacute cerebral ischema induced in a dog and to deter-mine whichmodality first detected cerebral ischemia. Materials and Methods : Experimental cerebral infarction was induced bythe occlusion of intracerebral arter-ies using embolic materials (polyvinyl-alcohol, 300 -6 00 μ) introducedthrough a microcatheter into the internal carotid artery of five dogs weighing 12 -20 kg. Serial CT and MR imageswere obtained at one hour intervals from one to five hours after occlusion, and were analyzed independently by tworadiologists. We assessed changes in attenuation, as seen on unenhanced CT and the signal intensity of the lesionon each MR image, and measured the contrast-to-noise ratio (CNR) of the lesions. Results : Ischemic lesions weredetected on unenhanced CT 1 -3 hours after occlusion of cerebral arteries. In all dogs, the lesions were detectedearliest on diffusion-weighted images obtained at 1 hour. They were detect-ed on T2-weighted images at 3 -5 hoursand on fast FLAIR images of 2 -5 hours. The CNR of ischemic lesions increased gradually during the 5-hour period.It was highest on diffusion-weighted images, while on unen-hanced CT, T2-weighted, and fast FLAIR images it wassimilar. Conclusion : Hyperacute ischemic lesions were detected earliest on diffusion-weighted images, and earlieron unenhanced CT than on fast FLAIR or T2-weighted MR image.

Purpose : To compare the detection rate of unenhanced CT, spin-echo T2-weighted, fast fluid-attenuatedin-version- recovery(FLAIR), and diffusion-weighted MR imaging in the diagnosis of hyperacute middle cerebralartery(MCA) territory infarction. Materials and Methods : Sixteen patients with clinically proven hyperacute MCAterritory infarction were e-valuated with unenhanced CT and MR. All CT examinations were performed within sixhours of the onset of symptoms and all MR studies were performed within two hours of CT. All images were evaluatedindepen-dently by two radiologists in possession of brief clinical information. Positive imaging criteria wereparenchy-mal hypoattenuation, as seen on CT, and increased signal intensity, as seen on MR. For quantitativeanalysis, we measured the attenuation and signal intensity of the lesion and contralateral normal parenchyma, andper-centage contrast-to-noise ratios(CNRs) of the lesions were also calculated . Results : Positive findings weredetected in all patients on diffusion-weighted images, in 13(81%) on CT, in 10 ( 63 %) on fast FLAIR images, andin 7(44 %) on T2-weighted images. Lesion percentage CNRs were 30% for diffusion-weighted imaging, 15 % for CT, 18% for FLAIR MR imaging, and 16 % for T2-weighted MR imag-ing(p

Mediastinal interfaces on a chest radiograph result from contact between mediastinal structures and the adjacent lung, while mediastinal lines result from contact between the two lungs across the midline. A variation of mediastinal interface is mediastinal stripe, a narrow band produced by contact of both sides of a mediastinal structure with the lungs. Alterations in mediastinal interfaces and lines may be due to variations in normal anatomy, or may reflect the presence of a abnormalities within the mediastinum. Familiarity with the various normal mediastinal interfaces and lines, and the changes that occur with disease is important for the interpretation of the chest radiograph and in the diagnosis of mediastinal abnormalities. The purpose of this pictorial essay is to illustrate the most imortant normal and abnormal interfaces and lines and also to correlate radiography and CT findings.