Treatable fluctuating Parkinsonism and dementia in a patient with a dural arteriovenous fistula.
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Aged↗
Biomedical subjects
Toshiaki Taoka
Publications and source records attributed to Toshiaki Taoka.
Pituitary stalk compression by the dorsum sellae: possible cause for late childhood onset growth disorders.
PURPOSE: The purpose of this study was to evaluate the relationship between pituitary stalk compression by the dorsum sellae and clinical or laboratory findings in short stature children. MATERIALS AND METHODS: We retrospectively reviewed magnetic resonance images of the pituitary gland and pituitary stalk for 34 short stature children with growth hormone (GH) deficiency and 24 age-matched control cases. We evaluated the degree of pituitary stalk compression caused by the dorsum sellae. Body height, GH level, pituitary height and onset age of the short stature were statistically compared between cases of pituitary stalk compression with associated stalk deformity and cases without compression. RESULTS: Compression of the pituitary stalk with associated stalk deformity was seen in nine cases within the short stature group. There were no cases observed in the control group. There were no significant differences found for body height, GH level and pituitary height between the cases of pituitary stalk compression with associated stalk deformity and cases without compression. However, a significant difference was seen in the onset age between cases with and without stalk compression. CONCLUSION: Pituitary stalk compression with stalk deformity caused by the dorsum sellae was significantly correlated with late childhood onset of short stature.
Adolescent↗
Displacement of the facial nerve course by vestibular schwannoma: preoperative visualization using diffusion tensor tractography.
PURPOSE: To preoperatively visualize the course of the facial nerve, which is displaced by vestibular schwannoma, using diffusion tensor (DT) tractography, and to evaluate the agreement with surgical findings. MATERIALS AND METHODS: The subjects were eight patients with vestibular schwannoma who had undergone removal surgery. DT MR images were obtained and tracts that were considered to represent the facial nerve were constructed. We assessed the success rate for tract construction and evaluated the agreement between tractography findings and surgery. RESULTS: We obtained a tract that connected the internal auditory meatus and brainstem, and was considered to represent the facial nerve in seven of eight cases. The course of the constructed tract agreed with surgical findings in five of these seven cases. One exception was a case in which the tumor was too large to enable intraoperative observation of the facial nerve; however, the facial nerve appeared to be displaced anteriorly at intracapsular resection, in agreement with tractography. In the other case, the schwannoma was mostly cystic. CONCLUSION: Tractographs constructed using MR tensor images enabled us to identify tracts considered to represent facial nerves. We consider DT tractography to be a useful tool for preoperatively predicting facial nerve displacement in vestibular schwannoma.
Adult↗
White matter T2 hyperintensity development and clinical deterioration after status epilepticus in a patient with dentatorubral-pallidoluysian atrophy.
Serial T2-weighted magnetic resonance imaging in a 29-year-old woman with juvenile type dentatorubral-pallidoluysian atrophy (DRPLA) demonstrated that a cerebral white matter hyperintensity appeared within 2 months after status epilepticus and persisted for more than 20 months. The patient had rapidly progressive mental regression and became akinetic after status epilepticus. The chronological relationship between the signal changes and the clinical deterioration suggested that the epilepsy, at least in part, contributed to the progression of white matter degeneration, the hallmark of DRPLA.
Adult↗
Serial therapy-induced changes in tumor shape in cervical cancer and their impact on assessing tumor volume and treatment response.
OBJECTIVE: The purpose of this study was to evaluate the patterns and distribution of tumor shape and its temporal change during radiation therapy (RT) in cervical cancer and the effect of tumor configuration changes on the correlation between region of interest (ROI)-based and diameter-based MRI tumor measurement. MATERIALS AND METHODS: Serial MRI examinations (T1-weighted and T2-weighted images) were performed in 60 patients (age range, 29-75 years; mean, 53.3 years) with advanced cervical cancer (stages IB2-IVB/recurrent) who were treated with RT at four time points: start of RT, during RT (at 2-2.5 and at 4-5 weeks of RT), and post-RT. Tumor configuration was classified qualitatively into oval, lobulated, and complex based on MR film review. Two methods of tumor volume measurement were compared: ellipsoid computation of three orthogonal diameters (diameter based) and ROI volumetry by delineating the entire tumor volume on the MR workstation (ROI based). Temporal changes of tumor shape and the respective tumor volumes measured by the two methods were analyzed using linear regression analysis. RESULTS: Most tumors (70%) had a non-oval (lobulated and complex) shape before RT and became increasingly irregular during and after RT: 84% at 2-2.5 weeks of RT (p = 0.037), 86% (p = 0.025) at 4-5 weeks, and 96% post-RT (p = 0.010), compared with 70% pre-RT. Diameter-based and ROI-based measurement correlated well before RT (r = 0.89) but not during RT (r = 0.68 at 2-2.5 weeks, r = 0.67 at 4-5 weeks of RT). CONCLUSION: Most cervical cancers are not oval in shape pretherapy, and they become increasingly irregular during and after therapy because of nonconcentric tumor shrinkage. ROI-based volumetry, which can optimally measure irregular volumes, may provide better response assessment during treatment than diameter-based measurement.
Adenocarcinoma↗
Proton MR spectroscopy of adult-onset dentatorubral-pallidoluysian atrophy.
PURPOSE: To quantify impairment of the basal ganglia (globus pallidus and thalamus) in adult-onset dentatorubral-pallidoluysian atrophy (DRPLA). METHODS: Five patients with genetically definite adult-onset DRPLA (aged 51 to 65 years, mean 55.6 years) and 5 age- and sex-matched healthy controls underwent conventional magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) of the brain in the voxels predominantly containing the globus pallidus or the thalamus. RESULTS: Conventional MRI studies showed apparently normal intensities in the globus pallidus and thalamus. MRS showed that the choline (Cho)/creatine (Cr) ratio for the patients' globus pallidus, the region preferentially affected in DRPLA, was significantly higher than that in the controls (p<0.05). The N-acetylaspartate (NAA)/Cr ratio for the globus pallidus and the Cho/Cr and NAA/Cr ratios for the thalamus, the region relatively spared in this disease, did not differ significantly between the patients and controls. CONCLUSIONS: MRS may sensitively and specifically detect biochemical alterations in susceptible regions of patients with adult-onset DRPLA.
Aged↗
Diffusion tensor imaging in cases with visual field defect after anterior temporal lobectomy.
BACKGROUND AND PURPOSE: Visual defect due to optic radiation injury is a complication of temporal lobectomy for temporal epilepsy. To investigate whether diffusion tensor imaging can delineate the changes in optic radiations after lobectomy, we evaluated parameters on tensor images for optic radiations and correlated them with visual defect. METHODS: We examined 14 cases after temporal lobectomy. Durations after surgeries ranged from 3 weeks to 9 years. The cases were classified into three groups on the basis of the severity of visual field defect (A-C, with group C the most severe). We evaluated signals on T2-weighted images and parameters of tensor images, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), for the optic radiation in both the operated and intact side. RESULTS: On T2-weighted images, high signals in optic radiations were seen in four cases, occurring more than 4 weeks after surgery. The mean operated-to-intact side FA ratio in the optic radiation decreased according to severity of visual defect (group A, 0.88; group B, 0.89; group C, 0.73). The mean operated-to-intact side ADC ratio showed no significant difference in the overall cases. The ratio for ADC, however, tended to increase according to visual defect in cases after 10 weeks postsurgery. CONCLUSION: Optic radiation showed a decreased FA value in cases after temporal lobectomy. In later stages, ADC values tended to increase and high signal intensities on T2-weighted images were observed. The FA value can be used for evaluating Wallerian degeneration of optic radiation even in the early stages after surgery.
Adult↗
Signal characteristics of FLAIR related to water content: comparison with conventional spin echo imaging in infarcted rat brain.
To examine the correlation between tissue water content and signal intensity on fluid-attenuated inversion recovery (FLAIR) images, we analyzed infarcted rat brain, verified the results by theoretical simulation, and compared them with conventional spin-echo images. We produced brain infarction with cavitation in five rats by middle cerebral artery occlusion. After in vivo MRI, histologic sections of the MRI plane were obtained. We measured the signal intensity of regions on FLAIR and spin-echo images, and measured the area of cavitation on histologic sections. We plotted curves of cavity percentage to signal intensity. Theoretical values were calculated using a two-compartment model. On the curve of cavity area to signal intensity, the signal on FLAIR images peaked in tissues with 20% to 30% area of cavitation. On the theoretical curve, the signal on FLAIR images peaked at 90% tissue water content. These results seem to be characteristic of FLAIR.
Animals↗
Paradoxical parasellar high signals resembling shunt diseases on routine 3D time-of-flight MR angiography of the brain: mechanism for the signals and differential diagnosis from shunt diseases.
BACKGROUND AND PURPOSE: We occasionally encounter phenomena in which venous flow signals of the cavernous sinus (CS) and/or inferior petrosal sinus (IPS) are visualized paradoxically in patients without arteriovenous shunt in 3D time-of-flight magnetic resonance angiography (3D-TOF MRA) of the brain. The aims of this study are to examine the frequency and cause of this phenomenon ("pseudo-shunt" image) and to determine points of differentiation from definite arteriovenous shunt images ("real shunt"). METHODS: We retrospectively examined 85 maximum intensity projection images obtained by MRA in the absence of arteriovenous shunts to detect pseudo-shunt images, and evaluated source images of pseudo-shunt studies for venous structures. Four real-shunt MRA studies were compared with pseudo-shunt studies on three points: (1) extension of sinuses, (2) extension of cortical veins, and (3) signal intensity of sinuses as assessed by the scoring method (1 point when these findings exist, 0 when they do not). RESULTS: We detected five CS (3%) and six IPS (4%) signals in 9 (11%) of the 85 cases. In the source images of four pseudo-shunt images in the CS, we detected signals from the sphenoparietal sinus (SPS). The average score was significantly lower in the pseudo-shunt (0.22) than the real-shunt (2.75) images (P < .0001). CONCLUSION: In cerebral 3D-TOF MRA, pseudo-shunt images were seen in 11% (9/85) of the study population, with antegrade upward blood flow of the SPS considered as one of the causes. Real-shunt signals can be distinguished from pseudo-shunt signals by evaluation of source images.
Adolescent↗
Retinotopy with coordinates of lateral occipital cortex in humans.
OBJECT: The lateral occipital cortex in humans is known as the "extrastriate visual cortex." It is, however, an unexplored field of research, and the anatomical nomenclature for its surface has still not been standardized. This study was designed to investigate whether the lateral occipital cortex in humans has retinotopic representation. METHODS: Four right-handed patients with a diagnosis of intractable epilepsy from space-occupying lesions in the occipital lobe or epilepsy originating in the occipital lobe received permanently implanted subdural electrodes. Electrical cortical stimulation was applied directly applied to the brain through metal electrodes by using a biphasic stimulator. The location of each electrode was measured on a lateral skull x-ray study. Each patient considered a whiteboard with vertical and horizontal median lines. The patient was asked to look at the midpoint on the whiteboard. If a visual hallucination or illusion occurred, the patient recorded its outline, shape, color, location, and motion on white paper one tenth the size of, and with vertical and horizontal median lines similar to those on, the whiteboard. Polar angles and eccentricities of the midpoints of the phosphenes from the coordinate origin were measured on the paper. On stimulation of the lateral occipital lobe, 44 phosphenes occurred. All phosphenes were circular or dotted, with a diameter of approximately 1 cm, except one that was like a curtain in the peripheral end of the upper and lower visual fields on stimulation of the parietooccipital region. All phosphenes appeared in the visual field contralateral to the cerebral hemisphere stimulated. On stimulation of the lateral occipital lobe, 22 phosphenes moved centrifugally or toward a horizontal line. From three-dimensional scatterplots and contour maps of the polar angles and eccentricities in relation to the x-ray coordinates of the electrodes, one can infer that the lateral occipital cortex in humans has retinotopic representation. CONCLUSIONS: The authors found that phosphenes induced by electrical cortical stimulation of the lateral occipital cortex represent retinotopy. From these results one can assert that visual field representation with retinotopic relation exists in the extrastriate visual cortex.
Adult↗
Distinguishing between anterior cerebral artery and middle cerebral artery perfusion by color-coded perfusion direction mapping with arterial spin labeling.
The purpose of this study was to evaluate collateral circulation by describing anterior cerebral artery and middle cerebral artery perfusion areas. Pairs of image sets spin labeled on the medial and lateral side were used. A pixel-by-pixel t test was performed, with blue gradation used to display lateral perfusion (ie, middle cerebral artery) and orange gradation for anterior cerebral artery perfusion. Extensions of anterior cerebral artery perfusion areas in cases of middle cerebral artery stenosis were described. This method may aid in estimation of collateral circulation for stroke treatment.
Cerebral Angiography↗
Magnetic resonance imaging shows delayed ischemic striatal neurodegeneration.
Brief focal ischemia leading to temporary neurological deficits induces delayed hyperintensity on T1-weighted magnetic resonance imaging (MRI) in the striatum of humans and rats. The T1 hyperintensity may stem from biochemical alterations including manganese (Mn) accumulation after ischemia. To clarify the significance of this MRI modification, we investigated the changes in the dorsolateral striatum of rats from 4 hours through 16 weeks after a 15-minute period of middle cerebral artery occlusion (MCAO), for MRI changes, Mn concentration, neuronal number, reactivities of astrocytes and microglia/macrophages, mitochondrial Mn-superoxide dismutase (Mn-SOD), glutamine synthetase (GS), and amyloid precursor protein. The cognitive and behavioral studies were performed in patients and rats and compared with striatal T1 hyperintensity to show whether alteration in brain function correlated with MRI and histological changes. The T1-weighted MRI signal intensity of the dorsolateral striatum increased from 5 days to 4 weeks after 15-minute MCAO, and subsequently decreased until 16 weeks. The Mn concentration of the dorsolateral striatum increased after ischemia in concert with induction of Mn-SOD and GS in reactive astrocytes. The neuronal survival ratio in the dorsolateral striatum decreased significantly from 4 hours through 16 weeks, accompanied by extracellular amyloid precursor protein accumulation and chronic glial/inflammatory responses. The patients and rats with neuroradiological striatal degeneration had late-onset cognitive and/or behavioral declines after brief focal ischemia. This study suggests that (1) the hyperintensity on T1-weighted MRI after mild ischemia may involve tissue Mn accumulation accompanied by Mn-SOD and GS induction in reactive astrocytes, (2) the MRI changes correspond to striatal neurodegeneration with a chronic inflammatory response and signs of oxidative stress, and (3) the subjects with these MRI changes are at risk for showing a late impairment of brain function even though the transient ischemia is followed by total neurological recovery.
Aged↗
Method and timing of tumor volume measurement for outcome prediction in cervical cancer using magnetic resonance imaging.
PURPOSE: Recently, imaging-based tumor volume before, during, and after radiation therapy (RT) has been shown to predict tumor response in cervical cancer. However, the effectiveness of different methods and timing of imaging-based tumor size assessment have not been investigated. The purpose of this study was to compare the predictive value for treatment outcome derived from simple diameter-based ellipsoid tumor volume measurement using orthogonal diameters (with ellipsoid computation) with that derived from more complex contour tracing/region-of-interest (ROI) analysis 3D tumor volumetry. METHODS AND MATERIALS: Serial magnetic resonance imaging (MRI) examinations were prospectively performed in 60 patients with advanced cervical cancer (Stages IB2-IVB/recurrent) at the start of RT, during early RT (20-25 Gy), mid-RT (45-50 Gy), and at follow-up (1-2 months after RT completion). ROI-based volumetry was derived by tracing the entire tumor region in each MR slice on the computer work station. For the diameter-based surrogate "ellipsoid volume," the three orthogonal diameters (d1, d2, d3) were measured on film hard copies to calculate volume as an ellipsoid (d1 x d2 x d3 x pi/6). Serial tumor volumes and regression rates determined by each method were correlated with local control, disease-free and overall survival, and the results were compared between the two measuring methods. Median post-therapy follow-up was 4.9 years (range, 2.0-8.2 years). RESULTS: The best method and time point of tumor size measurement for the prediction of outcome was the tumor regression rate in the mid-therapy MRI examination (at 45-50 Gy) using 3D ROI volumetry. For the pre-RT measurement both the diameter-based method and ROI volumetry provided similar predictive accuracy, particularly for patients with small (<40 cm3) and large (> or =100 cm3) pre-RT tumor size. However, the pre-RT tumor size measured by either method had much less predictive value for the intermediate-size (40-99 cm3) tumors, which accounted for the majority of patients (55%). Tumor regression rate (fast vs. slow) obtained during mid-RT (45-50 Gy), which could only be appreciated by 3D ROI volumetry, had the best outcome prediction rate for local control (84% vs. 22%, p < 0.0001) and disease-free survival (63% vs. 20%, p = 0.0005). Within the difficult to classify intermediate pre-RT size group, slow ROI-based regression rate predicted all treatment failures (local control rate: 0% vs. 91%, p < 0.0001; disease-free survival: 0% vs. 73%, p < 0.0001). Mid-RT regression rate based on simple diameter measurement did not predict outcome. The early-RT and post-RT measurements were least useful with either measuring method. CONCLUSION: Our preliminary data suggest that for the prediction of treatment outcome in cervical cancer, initial tumor volume can be estimated by simple diameter-based measurement obtained from film hard copies. When initial tumor volume is in the intermediate size range, ROI volumetry and an additional MRI during RT are needed to quantitatively analyze tumor regression rate for the prediction of treatment outcome.
Adenocarcinoma↗
[Evaluation of appearance with high-speed CE-3dMRDSA in brain].
We evaluated the fitting scan technique for CE-3dMRDSA, and found common ground that determines spatial resolution and time resolution (slab thickness and partition number). We also examined the relation between appearance and time resolution (volume of contrast medium and injection speed). To obtain good image contrast, the volume of contrast medium needs to be at least 7 ml and suitable for an injection speed of 3-5 ml/sec. However, when we increased the volume of contrast medium and decreased injection speed, changes in MRDSA images with time became worse. The measure of the bolus with contrast medium was found to determine image contrast. When contrast medium is injected earlier, it circulates earlier within the brain. If the scan time is not short enough, it is not possible to observe changes in MRDSA images. And when spatial resolution is improved, time resolution becomes worse. Therefore, it is important to find the point of compromise between spatial resolution and time resolution. If we look for anterior MIP images, the CNR in the spatial resolution didn't change, when the slice thickness is more than 3 mm. Because, the partial volume effect decide the image contrast. However, unless the view is from the front, slice thickness influences spatial resolution. Therefore, when we view MIP images from the lateral direction, slice thickness must be set at less than 2 mm. Results indicated that, in CE-3dMRDSA with the fitting technique, slice thickness should be less than 3 mm, partition number 16-20, slab thickness 48 mm, contrast medium volume 7-10 ml, and injection speed 3-5 ml.
Adult↗
Evaluation of arteriosclerotic changes in the intracranial carotid artery using the calcium score obtained on plain cranial computed tomography scan: Correlation with angiographic changes and clinical outcome.
PURPOSE: This study evaluated the correlation between quantified calcification of the carotid siphon and arteriosclerotic changes on angiography as well as clinical outcome. We used the calcium score obtained from intracranial carotid arteries viewed on plain CT. METHOD/MATERIALS: We examined carotid siphons of 72 consecutive patients who had undergone both plain CT and angiography of the brain. We calculated calcium scores of the carotid siphon. Arteriosclerotic changes on angiography were categorized as "smooth," "irregular," or "stenosis." We assessed the correlation between the scores and arteriosclerotic changes both in the carotid siphon and the bifurcation. We reviewed clinical records approximately 2 years after examination and evaluated the scores of patients who did and did not experience cerebral strokes. RESULTS: In the evaluation between angiographic findings of siphon and calcium score of the siphon, there were statistically significant differences between the "smooth" and "irregular", "irregular" and "stenosis" and the "smooth" and "stenosis". In the evaluation between angiographic findings of bifurcation and the score of the siphon, a statistically significant difference was only seen between "smooth" and "stenosis". No significant differences in calcium scores were observed between patients groups who did or did not experience a cerebral stroke. CONCLUSIONS: There were a positive correlation between calcium scores on CT and angiographic changes of arteriosclerosis in the siphon as well as bifurcation, indicating angiographic changes can be predicted using calcium scores. However, the degree of calcification in the siphon cannot be used to predict the possibility of a future cerebral stroke.
Aged↗
Evaluation of extraocular muscles using dynamic contrast enhanced MRI in patients with chronic thyroid orbitopathy.
OBJECTIVE: The purpose of the current study is to investigate the underlying pathophysiological changes of extraocular muscle (EOM) in Graves orbitopathy using dynamic contrast MR imaging and to correlate these MR functional changes with the anatomic abnormalities. METHODS: EOMs of 16 patients with Graves disease and 12 normal volunteers were examined by dynamic enhanced MRI. We quantified the peak enhancement ratio of EOMs and calculated the ratio versus temporalis muscle and the ratio of maximum upslope versus temporalis muscle. We compared the ratios between normal volunteers and patient groups. RESULTS: Mean of peak enhancement ratio values for the EOMs in patients with Graves disease tends to decrease according to the severity of the anatomic and clinical changes. The mean maximum upslope also decreased according to the severity of the disease for EOMs. CONCLUSION: Hemodynamic information obtained by dynamic contrast enhanced MRI is useful in evaluating the clinical course of thyroid orbitopathy.
Adolescent↗