Prediction of hard meningiomas: quantitative evaluation based on the magnetic resonance signal intensity.

BACKGROUND: From a surgical perspective, presurgical prediction of meningioma consistency is beneficial. PURPOSE: To quantitatively analyze the correlation between the magnetic resonance (MR) signal intensity (SI) or apparent diffusion coefficient (ADC) and meningioma consistency and to determine which MR sequence could help predicting hard meningiomas. MATERIAL AND METHODS: This study included 43 patients with meningiomas who underwent preoperative MR imaging (MRI), including T1-weighted (T1W) imaging, T2-weighted (T2W) imaging, fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI), contrast-enhanced (CE)-T1W imaging, and CE-fast imaging employing steady-state acquisition (FIESTA). A neurosurgeon evaluated the tumor consistency using a visual analog scale (VAS) with the anchors "soft" (score = 0) and "hard" (score = 10). The SI ratio (tumor to cerebral cortex SI) and ADC value were compared with the tumor consistency. The sensitivity, specificity, and accuracy for predicting hard meningiomas (VAS score ≥8; 9 of 43 patients) were calculated using cutoff values for the SI ratio that were obtained in a receiver operating characteristic curve analysis. RESULTS: A significant negative correlation was observed between the tumor consistency and the SI ratio on T2W imaging, FLAIR, and CE-FIESTA (P < 0.05) but not on T1W imaging, CE-T1W imaging, and the ADC value. The sensitivity, specificity, and accuracy for predicting hard meningiomas were 89%, 79%, and 81% with T2W imaging; 89%, 76%, and 79% with FLAIR; and 100%, 74%, and 79% with CE-FIESTA, respectively. CONCLUSION: Our results suggest that a quantitative assessment using conventional T2W imaging or FLAIR may be a simple and useful method for predicting hard meningiomas.

Internal structures of the globus pallidus in patients with Parkinson's disease: evaluation with quantitative susceptibility mapping (QSM).

OBJECTIVES: The aim of this study was to assess the susceptibility change in medial and lateral globus pallidus (GPm and GPl) related to age separately, using quantitative susceptibility mapping (QSM) and to determine whether QSM can depict GPm in Parkinson's disease (PD) patients. METHODS: QSM was performed in 19 PD patients and in 41 normal control (NC) subjects. First, we quantitatively analysed age-related changes in QSM value in NC for GPl and GPm by a manual region of interest (ROI) technique. Then, in PD patients and age-matched NC subjects, we evaluated the depiction of GPm on QSM images qualitatively. RESULTS: In NC, the QSM value within GPl significantly increased gradually with age (r = 0.32, p = 0.04), whereas it did not change with age in GPm. The average QSM value was significantly larger for GPl than for GPm (205 vs 191, p < 0.05). In both PD patients and age-matched NC, the depiction of GPm on QSM images was good in most cases (87 %, 33 of 38 sides in PD patients) mainly because of the differences in susceptibility between GPm and GPl. CONCLUSIONS: The QSM value in GPl increases gradually with age, which allows for the identification of GPm in elderly PD subjects.

Diagnosis of intracranial hemorrhagic lesions: comparison between 3D-SWAN (3D T2*-weighted imaging with multi-echo acquisition) and 2D-T2*-weighted imaging.

BACKGROUND: 3D-susceptibility-weighted angiography (SWAN) can produce high-resolution images that yield excellent susceptibility-weighted contrast at a relatively short acquisition time. PURPOSE: To compare SWAN- and 2D-T2*-weighted gradient-echo images (T2*-WI) for their sensitivity in the depiction of cerebral hemorrhagic lesions. MATERIAL AND METHODS: We subjected 75 patients with suspected cerebral hemorrhagic lesions to SWAN and T2*-WI at 3T. We first measured the contrast-to-noise ratio (CNR) using an agar phantom that contained different concentrations of superparamagnetic iron oxide (SPIO). The acquisition time for SWAN and T2*-WI was similar (182 vs. 196 s). Neuroradiologists compared the two imaging methods for lesion detectability and conspicuity. RESULTS: The CNR of the phantom was higher on SWAN images. Of the 75 patients, 50 were found to have a total of 278 cerebral hemorrhagic lesions (microbleeds, n = 229 [82.4%]; intracerebral hemorrhage, n = 18 [6.5%]; superficial siderosis, n = 13 [4.7%]; axonal injuries, n = 8 [2.9%]; subarachnoid hemorrhage [SAH] or brain contusion, n = 3 each [1.0%]; subdural hematoma, n = 2 [0.7%]; cavernous hemangioma or dural arterteriovenous fistula, n = 1 each [0.4%]). In none of the lesions was the SWAN sequence inferior to T2*-WI with respect to lesion detectability and conspicuity. In fact, SWAN yielded better lesion conspicuity in patients with superficial siderosis and SAH: it detected significantly more lesions than T2*-WI (P < 0.01) and it was particularly useful for the detection of microbleeds and lesions near the skull base. CONCLUSION: SWAN is equal or superior to standard T2*-WI for the diagnosis of various cerebral hemorrhagic lesions. Because its acquisition time is reasonable it may replace T2*-WI.

Parkinson's disease: diagnostic potential of high-resolution phase difference enhanced MR imaging at 3 T.

OBJECTIVES: To determine whether it is possible to diagnose patients with Parkinson's disease (PD) on an individual basis using magnetic resonance imaging with phase difference enhanced imaging (PADRE). METHODS: PADRE delineated the crural fibres as a layer of low signal intensity and the substantia nigra as a layer of medium signal intensity in a healthy volunteer, and showed a clear boundary between the crural fibres and the substantia nigra (BCS). Twenty-four PD patients and 24 control subjects were enrolled. Contrast ratios between the substantia nigra and occipital white matter were calculated, and two radiologists independently reviewed the PADRE findings regarding BCS obscuration. RESULTS: Mean contrast ratio in PD patients was significantly higher than in control subjects (0.56 vs 0.39, P < 0.01). The BCS on PADRE was obscured significantly more frequently in any subgroups with PD patients compared with control subjects (P < 0.01). The observation of BCS obscuration had a sensitivity, specificity and accuracy for the diagnosis of PD of 92 %, 88 % and 90 % for radiologist 1 and 83 %, 88 % and 85 % for radiologist 2, respectively. CONCLUSION: PADRE is able to identify PD in patients as a loss of delineation between the crural fibres and the substantia nigra on an individual basis.

Delineation of optic nerves and chiasm in close proximity to large suprasellar tumors with contrast-enhanced FIESTA MR imaging.

PURPOSE: To evaluate whether contrast material-enhanced (CE) fast imaging employing steady-state acquisition (FIESTA) can depict the anterior optic pathways in patients with large suprasellar tumors. MATERIALS AND METHODS: Institutional review board approval was obtained. Twenty-eight patients with large suprasellar tumors undergoing surgical treatment (19 pituitary adenomas, six meningiomas, and three additional miscellaneous tumors) underwent preoperative magnetic resonance (MR) imaging, including CE FIESTA, at 3.0 T. Two radiologists assessed the visibility of five segments of the optic pathways (bilateral optic nerves and optic tracts, optic chiasm) with CE FIESTA and conventional MR imaging, including thin-section coronal T2-weighted imaging and CE T1-weighted imaging, by using a three-point scale. Moreover, the preoperative signal intensity of the optic pathways was correlated with pre- and postoperative visual impairment to determine whether high signal intensity at CE FIESTA is predictive of persistence of visual impairment after surgery. The χ(2) test was used to compare scores assigned to CE FIESTA and conventional MR images. RESULTS: The percentage of anterior optic pathways rated as visible was significantly higher with CE FIESTA than with conventional MR imaging (100% [140 of 140 segments] vs 78% [109 of 140 segments], P < .05). Thirty-one of the 140 segments (22%) were not depicted with conventional MR imaging; all of these 31 segments were visualized with CE FIESTA. For 12 patients who underwent transcranial surgery, the anatomic locations of the optic pathways at CE FIESTA were compatible with the surgical findings. CE FIESTA helped predict persistent visual impairment after surgical treatment with a sensitivity of 75% (three of four patients) and a specificity of 96% (23 of 24 patients). The accuracy of CT FIESTA in the prediction of visual loss was significantly higher than that of T2-weighted imaging (93% [26 of 28 patients] vs 50% [14 of 28 patients], P < .05). CONCLUSION: CE FIESTA is useful for the preoperative localization of the anterior optic pathways in patients with large suprasellar tumors and offers the potential to predict persistent visual impairment after decompression.

A novel tract imaging technique of the brainstem using phase difference enhanced imaging: normal anatomy and initial experience in multiple system atrophy.

OBJECTIVES: To develop a new tract imaging technique for visualising small fibre tracts of the brainstem and for detecting the abnormalities in multiple system atrophy of the cerebellar type (MSA-C) using a phase difference enhanced (PADRE) imaging technique, in which the phase difference between the target and surrounding tissue is selectively enhanced. METHODS: Two neuroradiologists compared the high-spatial-resolution PADRE imaging, which was acquired from six healthy volunteers, three patients with MSA-C, and 7 patients with other types of neurodegenerative diseases involving the brainstem or cerebellum. RESULTS: Various fine fibre tracts in the brainstem, the superior and inferior cerebellar peduncles, medial lemniscus, spinothalamic tract, medial longitudinal fasciculus, central tegmental tract, corticospinal tract and transverse pontine fibres, were identified on PADRE imaging. PADRE imaging from MSA-C demonstrated the disappearance of transverse pontine fibres and significant atrophy of the inferior cerebellar peduncles, while the superior cerebellar peduncles were intact. PADRE imaging also demonstrated that the transverse pontine fibres and inferior cerebellar peduncle were not involved in the other neurodegenerative diseases. CONCLUSION: PADRE imaging can offer a new form of tract imaging of the brainstem and may have the potential to reinforce the clinical utility of MRI in differentiating MSA from other conditions.

Influence of work shift on glutamic acid and gamma-aminobutyric acid (GABA): evaluation with proton magnetic resonance spectroscopy at 3T.

Working conditions such as shift work constitute a well-known risk factor for insomnia and excessive daytime sleepiness complaints. We compared brain gamma-aminobutyric acid (GABA), glutamic acid (Glu), glutamine (Gln), and Glx (Glu+Gln) levels in day-shift versus alternate-shift workers with proton magnetic resonance spectroscopy ((1)H-MRS) at 3T. The study population consisted of 32 healthy adult volunteers (16 day-shift and 16 alternate-shift workers). Each subject underwent MRS conducted using a MEGA-PRESS sequence in the early morning and early evening on the same day. Spectroscopy voxels (3.0 cm × 3.0 cm × 3.0 cm) were placed in the frontal lobe and parieto-occipital lobe. The GABA/Cr ratio in the frontal lobe was significantly lower for the alternate-shift group than for the day-shift group in the early evening (1.885 vs. 0.875). For the other metabolite ratios (Gln/Cr and Glx/Cr), there were no significant differences between the two groups regardless of morning or evening schedule. Our preliminary finding represents a possible alteration of GABA content in the brain related to an irregular work schedule.

Partial loss of hippocampal striation in medial temporal lobe epilepsy: pilot evaluation with high-spatial-resolution T2-weighted MR imaging at 3.0 T.

PURPOSE: To determine whether partial loss of the hippocampal striation (PLHS) at 3.0 T is more accurate than the currently accepted methods of using conventional magnetic resonance (MR) imaging to detect hippocampal sclerosis in medial temporal lobe epilepsy (MTLE). MATERIALS AND METHODS: This retrospective study had institutional review board approval, and informed consent was waived. Fluid-attenuated inversion-recovery (FLAIR) MR images and T2-weighted MR images in the oblique coronal plane in 22 consecutive patients (10 men, 12 female patients; mean age, 41.0 years; range, 14-76 years) (25 hemispheres) with a clinical diagnosis of MTLE were retrospectively evaluated. Twenty-five hippocampi in 15 subjects without epilepsy were evaluated as age-matched controls. The volumes and thicknesses of the four anatomic sections of the hippocampi were quantitatively measured on the T2-weighted images. Two radiologists independently reviewed the MR imaging findings of the hippocampus regarding atrophy, abnormal signal intensity, and PLHS on each side separately, without comparing both sides. Sensitivity and specificity were calculated among the MR imaging findings. RESULTS: Signal intensity abnormality on FLAIR images had a sensitivity of 36%, a specificity of 96%, and an accuracy of 66% for the diagnosis of hippocampal sclerosis. PLHS on T2-weighted MR images had a sensitivity of 76% and a specificity of 80% for the diagnosis of hippocampal sclerosis. The sensitivity for PLHS was higher than that for atrophy (44%) and abnormal signal intensity (48%) of the hippocampus on T2-weighted MR images. Although the mean volume of the hippocampus and the thickness of the hippocampal body were significantly smaller for patients with MTLE than for control subjects (P < .001 for both), there was no clear distinguishing threshold value between abnormal and normal hippocampi. CONCLUSION: PLHS showed the highest sensitivity for MTLE. This MR imaging feature might improve the accuracy of the diagnosis of bilateral hippocampal sclerosis, although further research is required.

Signal intensity of motor and sensory cortices on T2-weighted and FLAIR images: intraindividual comparison of 1.5T and 3T MRI.

We compared the signal intensity of motor and sensory cortices on T2-weighted and FLAIR images obtained at 3T and 1.5T. MR images of 101 consecutive neurologically normal patients who underwent both 1.5T and 3T MRI were retrospectively evaluated. The signal intensities of motor and sensory cortices were analyzed both visually and quantitatively in comparison with superior frontal cortex. On T2-weighted images, decreased signal intensity of the motor cortex was seen in 6 (32%) of 19 patients aged 61-70 years and 14 (48%) of 29 at 71 years and older at 3T, compared with only 1 (5%) and 2 (7%) at 1.5T, respectively. On FLAIR images, the decreased signal intensity in the motor cortex was also more frequently seen at 3T than at 1.5T. The mean CNRs of motor and sensory cortices were significantly higher at 3T than at 1.5T on both T2-weighted and FLAIR images. The decreased signal intensity in the motor cortex was frequently seen at 3T compared with 1.5T. Knowledge of the finding at 3T can help the recognition of abnormalities of the motor cortex caused by various pathologic conditions.

3D TOF MRA of intracranial aneurysms at 1.5 T and 3 T: influence of matrix, parallel imaging, and acquisition time on image quality - a vascular phantom study.

RATIONALE AND OBJECTIVES: A 3-T magnetic resonance imaging system provides a better signal-to-noise ratio and inflow effect than 1.5 T in three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA). The purpose of this study is to analyze the influence of matrix, parallel imaging, and acquisition time on image quality of 3D TOF MRA at 1.5 and 3 T, and to illustrate whether the combination of larger matrixes with parallel imaging technique is feasible, by evaluating the visualization of simulated intracranial aneurysms and aneurysmal blebs using a vascular phantom with pulsatile flow. MATERIALS AND METHODS: An anthropomorphic vascular phantom was designed to simulate the various intracranial aneurysms with aneurysmal bleb. The vascular phantom was connected to an electromagnetic flow pump with pulsatile flow, and we obtained 1.5- and 3-T MRAs altering the parameters of 3D TOF sequences, including acquisition time. Two radiologists evaluated the depiction of simulated aneurysms and aneurysmal blebs. RESULTS: The aneurysmal blebs were not sufficiently visualized on the high-spatial resolution 1.5-T MRA (matrix size of 384 x 256 or 512 x 256), even with longer acquisition time (9 or 18 min). At 3 T with acquisition time of 4.5 min using parallel imaging technique, however, the depiction of aneurysmal blebs was significantly better for the high-spatial resolution sequence than for the standard resolution sequence. For the high-spatial resolution sequence, the longer acquisition times did not improve the depiction of aneurysmal blebs in comparison with 4.5 min at 3 T. CONCLUSIONS: For 3D TOF MRA, the combination of the large matrix with parallel imaging technique is feasible at 3 T, but not at 1.5 T.

Effect of prophylactic hyperbaric oxygen treatment for radiation-induced brain injury after stereotactic radiosurgery of brain metastases.

PURPOSE: The purpose of the present study was to evaluate the prophylactic effect of hyperbaric oxygen (HBO) therapy for radiation-induced brain injury in patients with brain metastasis treated with stereotactic radiosurgery (SRS). METHODS AND MATERIALS: The data of 78 patients presenting with 101 brain metastases treated with SRS between October 1994 and September 2003 were retrospectively analyzed. A total of 32 patients with 47 brain metastases were treated with prophylactic HBO (HBO group), which included all 21 patients who underwent subsequent or prior radiotherapy and 11 patients with common predictors of longer survival, such as inactive extracranial tumors and younger age. The other 46 patients with 54 brain metastases did not undergo HBO (non-HBO group). The radiation-induced brain injuries were divided into two categories, white matter injury (WMI) and radiation necrosis (RN), on the basis of imaging findings. RESULTS: The radiation-induced brain injury occurred in 5 lesions (11%) in the HBO group (2 WMIs and 3 RNs) and in 11 (20%) in the non-HBO group (9 WMIs and 2 RNs). The WMI was less frequent for the HBO group than for the non-HBO group (p = 0.05), although multivariate analysis by logistic regression showed that WMI was not significantly correlated with HBO (p = 0.07). The 1-year actuarial probability of WMI was significantly better for the HBO group (2%) than for the non-HBO group (36%) (p < 0.05). CONCLUSIONS: The present study showed a potential value of prophylactic HBO for the radiation-induced WMIs, which justifies further evaluation to confirm its definite benefit.

Internal Structures of the Globus Pallidus in Patients with Parkinson's Disease: Evaluation with Phase Difference-enhanced Imaging.

PURPOSE: The medial medullary lamina (MML) separates the medial globus pallidus (GPm) from the lateral. The aim of this study was to assess the changes in appearance of MML related to age using the phase difference-enhanced (PADRE) imaging and to determine whether PADRE can depict the MML in the patients with Parkinson's disease (PD). MATERIALS AND METHODS: We enrolled 20 patients with PD and 50 normal control subjects (NC). First, for the visualization of the MML in the NC, we compared the PADRE, susceptibility-weighted imaging (SWI)-like images and T2 weighted imaging (WI) by using multiple comparison. The grading methods are as follows: grade 1; MML was not delineated, grade 2; less than half of MML was delineated, grade 3; more than half of MML was delineated and grade 4; whole MML was clearly delineated. We determined grade 3 and 4 as good depiction, delineating the GPm. Then, we evaluated patients with PD using the same method. RESULTS: In NC, the delineation of MML was good in 84% of cases on PADRE, but only 34% of cases showed a good depiction on SWI-like images (average grading score 3.31 vs 2.11, P < 0.05). No MML was delineated in all cases on T2 WI. Although younger subjects tended to show whole MML clearly, a part of MML tends to be obscured with age on PADRE. In patients with PD the depiction of MML on PADRE was also good in 90% of cases. CONCLUSION: The PADRE technique facilitates the depiction of the MML within globus pallidus (GP) on a broad range of age NC and patients with PD and it is superior to SWI-like images and T2 WI.

Juxtacortical Lesions in Multiple Sclerosis: Assessment of Gray Matter Involvement Using Phase Difference-enhanced Imaging (PADRE).

PURPOSE: In multiple sclerosis (MS), a juxtacortical lesion at the border between the gray matter (GM) and subcortical white matter (WM) may often involve the GM. A recently developed, phase-weighted magnetic resonance imaging (MRI) technique "phase difference enhanced imaging (PADRE)" can delineate the GM and WM clearly due to the difference in myelin concentration. We evaluated whether PADRE is useful for the detection of GM involvement in the juxtacortical MS lesions. METHODS: One neuroradiologist reviewed the conventional MRI in 13 MS patients and selected 48 juxtacortical lesions. At the first reading session with the conventional MRI alone (T2-weighted imaging, and two-dimensional and three-dimensional fluid-attenuated inversion recovery), two other neuroradiologists classified the lesions into three patterns according to their anatomical locations: (a) subcortical WM lesions involving the subcortical WM alone; (b) intracortical (IC) lesions involving the GM alone; (c) mixed GM/subcortical WM (mixed) lesions involving the both subcortical WM and GM. We defined the subcortical WM as a WM within a distance of 10 mm from inner edge of the GM. For the analyses, we excluded the white matter lesions further than 10 mm from inner edge of the GM. At the second reading session MRI and PADRE were available and the radiologists re-evaluated their prior classification. RESULTS: At the first reading session, 27 lesions were classified as (a), 1 as (b), and 20 as (c). Therefore, a total of 21 lesions (44%) were judged to involve the GM. At the second reading session, the classification of 15 (31%) lesions changed; all 15 lesions were judged to involve the GM on the PADRE. Interobserver agreement (kappa value) was 0.84 for the first- and 0.95 for the second reading session. CONCLUSION: PADRE is useful for detecting GM involvement of the juxtacortical MS lesions.

Hepatic sarcoidosis associated with chronic hepatitis C.

A 57-year-old woman with sarcoidosis was referred because of the appearance of multiple small low-attenuation areas in the liver on computed tomography (CT). A liver biopsy specimen showed chronic active hepatitis accompanied by sarcoid granulomas. The patient received prednisolone and, later, interferon-alpha. CT at 5 months of prednisolone treatment showed disappearance of the hepatic low-attenuation nodules. During long-term follow-up, however, these nodules reappeared on CT and liver cirrhosis finally developed. We present this case for two reasons: (1) hepatic sarcoidosis was associated with chronic active hepatitis C; (2) hepatic nodular lesions were evaluated by CT throughout the entire course, with CT scans having been taken from 2 years prior to their appearance.

[Paradoxical worsening ocular movement in idiopathic carotid-cavernous fistula without conjunctival congestion--case report].

We report a case of carotid-cavernous fistula(CCF) without conjunctival congestion and showing radiographically paradoxical worsening ocular movement. A 71-year-old woman suffered from mild double vision. The first carotid angiogram revealed left CCF, which was supplied by dural branches of the internal and external carotid arteries and drained out well via only the superior orbital vein to the angular vein. We did not perform intravascular intervention because of spontaneous improving of her symptom. However, three weeks after her discharge, her symptom began worsening and she was readmitted because of left complete ophthalmoplegia, but without conjunctival congestion. Contrary to our expectation the second left carotid angiogram demonstrated that the shunt flow to the angular vein of CCF was much less than that seen previously. After transvenous embolization of the left cavernous sinus, her symptom completely improved and CCF did not recur.

Systemic lupus erythematosus: prediction by MRI of the subsequent development of brain lesions.

RATIONALE AND OBJECTIVES: Many patients with systemic lupus erythematosus (SLE) manifest the recurrence of new brain lesions on follow-up magnetic resonance imaging (MRI) scans. We assessed whether the initial MRI findings help to predict the subsequent development of brain lesions in patients with SLE. MATERIALS AND METHODS: We enrolled 64 patients with SLE who had undergone initial and follow-up MRI studies. Two radiologists reviewed and categorized the initial MRI findings and divided the patients into those with no lesions on the initial and follow-up MRI scans (group A, n = 18), those with lesions on the initial scans only (group B, n = 32), and those with lesions on the first and new lesions on the follow-up MRI scans (group C, n = 14). We then looked for independent predictors of the subsequent development of brain lesions, such as antiphospholipid syndrome (APS) and findings on the initial MRI studies. RESULTS: The incidence of lacunar and localized cortical infarcts was significantly greater in group C than group B (50% vs. 0%, P < .001 and 50% vs. 9%, P < .05, respectively). Multivariate logistic regression analysis indicated that lacunar or localized cortical infarcts on the initial MRI scans were independent predictors of the subsequent development of brain lesions (odds ratio [OR]: 5.412, 95% confidence interval [CI]: 1.18-24.85, P = .03), whereas the presence of APS was not (OR: 0.621, 95% CI: 0.18-2.19). CONCLUSIONS: The presence of lacunar and/or localized cortical infarcts on initial MRI scans may predict the development of new brain lesions in patients with SLE.

[Cerebral infarction and intracranial aneurysm related to the reactivation of varicella zoster virus in a Japanese acquired immunodeficiency syndrome (AIDS) patient].

A 35-years-old right-handed man admitted to our hospital with a worsening of dysarthria, left facial palsy and left hemiparesis for 2 days. Acquired immunodeficiency syndrome (AIDS) was diagnosed when he was 28 years old. At that time, he also was treated for syphilis. After highly active antiretroviral treatment (HAART) was introduced at the age of 35 years old, serum level of human immunodeficiency virus (HIV) was not detected, but the number of CD4+ T cells was still less than 200/µl. He had no risk factors of atherosclerosis including hypertension, diabetes and hyperlipidemia. He had neither coagulation abnormality nor autoimmune disease. Magnetic resonance imaging (MRI) showed acute ischemic infarction spreading from the right corona radiate to the right internal capsule without contrast enhancement. Stenosis and occlusion of intracranial arteries were not detected by MR angiography. Although argatroban and edaravone were administered, his neurological deficits were worsened to be difficult to walk independently. Cerebrospinal fluid (CSF) examination showed a mild mononuclear pleocytosis (16/µl).　Oligoclonal band was positive. The titer of anti-varicella zoster virus (VZV) IgG antibodies was increased, that indicated VZV reactivation in the central nervous system (CNS), although VZV DNA PCR was not detected. Therefore, acyclovir (750 mg/day for 2 weeks) and valaciclovir (3,000 mg/day for 1 month) were administered in addition to stroke therapy. He recovered to be able to walk independently 2 month after the admission.Angiography uncovered a saccular aneurysm of 3 mm at the end of branch artery of right anterior cerebral artery, Heubner artery, 28 days after the admission. We speculated that VZV vasculopathy caused by VZV reactivation in CNS was involved in the pathomechanism of cerebral infarction rather than HIV vasculopathy in the case.

Pitfalls of 3D FLAIR brain imaging: a prospective comparison with 2D FLAIR.

RATIONALE AND OBJECTIVES: To prospectively compare the image contrast of various brain lesions on two-dimensional (2D) and three-dimensional (3D) fluid-attenuated inversion-recovery (FLAIR) images and to highlight the pitfalls of 3D FLAIR. MATERIALS AND METHODS: Institutional review board approval was obtained. We examined 94 brain lesions with 2D and 3D FLAIR at 3T. First, we optimized the repetition time and echo time of 3D FLAIR with a volunteer study. Then, we assessed the conspicuity and detection of the various lesions qualitatively, and the contrast ratio between the gray or white matter and lesions was calculated as a quantitative assessment. We also performed a phantom study to investigate the effects of different flow velocities on 2D and 3D FLAIR. RESULTS: With regard to the conspicuity and detection of most lesions (multiple sclerosis, ischemic lesions or infarction, brain tumors, or chronic trauma), 3D FLAIR was equal or superior to 2D FLAIR. For these lesions, the mean contrast ratios were higher on 3D FLAIR than on 2D FLAIR images. In terms of lesion conspicuity in the patients with hippocampal sclerosis and leptomeningeal metastasis, however, 3D FLAIR was equal or inferior to 2D FLAIR. The ivy sign in patients with moyamoya disease was frequently obscured on 3D FLAIR. The phantom study demonstrated that the signal-intensity ratio on 3D FLAIR decreased more rapidly with increasing velocity than that on 2D FLAIR. CONCLUSION: Although 3D FLAIR may replace 2D FLAIR images for most patients, radiologists should keep in mind that 3D has some pitfalls.

Delineation of optic radiation and stria of Gennari on high-resolution phase difference enhanced imaging.

RATIONALE AND OBJECTIVES: Phase difference enhanced (PADRE) imaging technique can selectively enhanced the phase difference between the target and surrounding tissue. Our purpose is to assess the delineations of the optic radiation and primary visual cortex (stria of Gennari) using PADRE. MATERIALS AND METHODS: The subjects were 6 healthy volunteers. Axial and coronal high-spatial resolution PADRE images were acquired covering the entire optic radiation using a 3T magnetic resonance system. Two radiologists evaluated the PADRE and susceptibility-weighted imaging (SWI)-like images for the delineation of four layers at the optic radiation (tapetum, internal sagittal stratum, external sagittal stratum, and adjacent white matter) on the basis of the anatomic appearances of the cadaveric specimens stained with Bodian's method and Kluver-Barrera method. The radiologists also assessed the delineations of the stria of Gennari on PADRE and SWI-like images. RESULTS: In all 6 healthy subjects, the PADRE images clearly identified the four layers at the optic radiation, as well as the stria of Gennari, which were difficult to appreciate in SWI-like images. The anatomic appearances of the optic radiation on PADRE images were more similar to those seen in the specimens stained with Kluver-Barrera method than with Bodian's method. CONCLUSION: The PADRE technique can delineate the four layers at the optic radiation and the stria of Gennari; the differences in myelin densities can also be enhanced. The PADRE technique may have the potential to reinforce the clinical utility of MRI in the diagnosis of diseases that affect the optic radiation and primary visual cortex.

Superficial siderosis associated with a chronic subdural hematoma: T2-weighted MR imaging at 3T.

RATIONALE AND OBJECTIVES: The purposes of this study were to assess the association between superficial siderosis (SS) and subdural hematoma (SDH) and to evaluate the magnetic resonance imaging (MR) characteristics of SS in patients with the presence or histories of SDH compared to those with histories of aneurysmal subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: A radiology database for a 4-year period contained data on patients with diagnoses of SDH. From these patients, 47 patients were further selected who underwent brain MR examinations using a 3-T MR system (the SDH group). Using T2-weighted images, two neuroradiologists evaluated the presence or absence and the characteristics of SS findings by comparing the patients with histories of aneurysmal subarachnoid hemorrhage (the SAH group; n = 36). The SS findings were classified into three types: apical (SS at the top of the surface of the gyrus of the cerebral hemisphere), gyral (SS surrounding the gyrus), and mixed. RESULTS: SS findings were seen in 13 patients (27.7%) in the SDH group (SS-SDH) and 13 patients (36.1%) in the SAH group (SS-SAH); all 13 cases of SS-SDH were the apical type, whereas the 13 cases of SS-SAH were either the gyral (n = 9 [69.2%]) or mixed (n = 4 [30.8%]) type. SS-SDH was seen only in the cerebral hemisphere ipsilateral to the side of the SDH (12 of 13 [92.3%]). All 13 cases of SS-SDH were accompanied by thinning of gray-matter intensity in the cerebral cortex, which was more frequently seen than in SS-SAH (P < .01). CONCLUSION: SDH occasionally causes the SS-like MR findings, and the pathogenesis of SS-SDH may be also different from that of SS-SAH.