Analysis of skeletal-muscle condition after excessive loading of the lower legs by sequential magnetic resonance imaging.

OBJECTIVES: To determine the changes of muscle conditions of lower leg after stretch shortening cycle exercises by MRI. SUBJECTS AND METHODS: This study included 20 healthy male adult volunteers. After conducting control MRI, each subject performed 3 sets of exercise loading, each set consisting of 100 repetitions of rebound jumping on one foot. MRIs were performed immediately after exercise loading (0 h), 6, 30, and 168 h later. After constructing T1/T2/Fractional Anisotropy (FA)/Apparent Diffusion Coefficient (ADC) maps, the changes of three skeletal muscles of the leg (the tibialis anterior [TA], soleus [SOL], and gastrocnemius [GA]) were quantitatively evaluated in each map at each time point. RESULTS: The T1 and T2 values were prolonged after exercise loading, and there was a delay in the recovery of T1 at 6 and 30 h after exercise loading, as compared to those of T2 values over time. The ADC values were elevated in all three muscles immediately after exercise loading, then recovered more slowly than T1 and T2, and still had not returned to baseline 168 h after exercise loading. The FA value decreased in all three muscles after exercise loading, with the greatest decrease occurring immediately after exercise loading. As with the ADC values, the FA values were slow to recover from the decrease, and had not returned to baseline levels 168 h post-loading. CONCLUSION: The delay of T1 value recovery suggested that the T1 value may reflect the muscle condition like fatigue and damage. Changes in the ADC and FA values over time suggested that structural changes such as minute muscular injuries can be detected by diffusion-weighted MRI. Meanwhile, the changes observed in the T1 and T2 values suggested that the measured relaxation time data reflected not only the water volume in the muscle, but also the muscle condition after exercise loading.

Associations among q-space MRI, diffusion-weighted MRI and histopathological parameters in meningiomas.

OBJECTIVES: The purposes of this MR-based study were to calculate q-space imaging (QSI)-derived mean displacement (MDP) in meningiomas, to evaluate the correlation of MDP values with apparent diffusion coefficient (ADC) and to investigate the relationships among these diffusion parameters, tumour cell count (TCC) and MIB-1 labelling index (LI). METHODS: MRI, including QSI and conventional diffusion-weighted imaging (DWI), was performed in 44 meningioma patients (52 lesions). ADC and MDP maps were acquired from post-processing of the data. Quantitative analyses of these maps were performed by applying regions of interest. Pearson correlation coefficients were calculated for ADC and MDP in all lesions and for ADC and TCC, MDP and TCC, ADC and MIB-1 LI, and MDP and MIB-1 LI in 17 patients who underwent subsequent surgery. RESULTS: ADC and MDP values were found to have a strong correlation: r = 0.78 (P = <0.0001). Both ADC and MDP values had a significant negative association with TCC: r = -0.53 (p = 0.02) and -0.48 (P = 0.04), respectively. MIB-1 LI was not, however, found to have a significant association with these diffusion parameters. CONCLUSION: In meningiomas, both ADC and MDP may be representative of cell density. KEY POINTS: • Diffusion-weighted MRI offers possibilities to assess the aggressiveness of meningiomas. • The q-space imaging-derived mean displacement correlates strongly with apparent diffusion coefficients. • Both diffusion parameters showed a strong negative association with tumour cell counts. • Derived mean displacement may help assess the aggressiveness of meningiomas preoperatively.

Age-related white matter changes in high b-value q-space diffusion-weighted imaging.

INTRODUCTION: To assess and compare age-related diffusion changes in the white matter in different cerebral lobes, as quantified by diffusion-weighted imaging (DWI) and high b-value q-space imaging (QSI). METHODS: Seventy-three cases without neurological symptoms or imaging abnormalities were grouped by age as young (<30 years, n = 20), middle-aged (30-49 years, n = 19), old (50-69 years, n = 18), and very old (> 70 years, n = 16) and imaged by a 1.5-T MR scanner for DWI and QSI. Apparent diffusion coefficient (ADC) and mean displacement (MDP) values were calculated in the white matter of frontal, parietal, and temporal lobes and compared using Dunnett's test, with the young group as a control. RESULTS: MDP values in frontal and parietal lobes were significantly higher in old and very old age groups than in the young, while those in the temporal lobes were significantly higher only in the very old group. ADC values were significantly higher in all three lobes in the very old group. CONCLUSION: QSI is more sensitive than DWI to age-related myelin loss in white matter.

Damage to the left ventral, arcuate fasciculus and superior longitudinal fasciculus-related pathways induces deficits in object naming, phonological language function and writing, respectively.

The anatomic localization of brain functions can be characterized via diffusion tensor imaging in patients with brain tumors and neurological symptoms. The goal of the present study was to evaluate the function of the ventral, arcuate fasciculus (AF) and the superior longitudinal fasciculus (SLF)-related language pathways using these techniques by analyzing 9 patients treated in our hospital between 2007 and 2011. In cases 1-3, the left ventral pathways, namely, the inferior longitudinal fasciculus, uncinate fasciculus or inferior fronto-occipital fasciculus, were mainly damaged, and the common dysfunction experienced by these patients was a deficit in object naming. In cases 4-6, the left SLF was mainly damaged, and the common deficit was dysgraphia. In cases 7-9, the left AF was mainly damaged, and almost all language functions related to phonology were abnormal. These results suggest that the left ventral, AF and SLF-related pathways are closely related to visual, auditory and hand-related language function, respectively.

Advantages and disadvantages of awake surgery for brain tumours in the primary motor cortex: institutional experience and review of literature.

Patients undergoing awake surgery for resection of brain tumours in the primary motor cortex (M1) are at high risk of developing new motor deficits. Thus, use of this procedure requires consideration of several important points, including the optimal modality to localise M1 on the affected side and the overall advantages and disadvantages of the procedure. In our experience with awake surgery for 21 brain tumours located in the M1 from January 2004 through October 2008, we found that functional magnetic resonance imaging was the most reliable modality in terms of localising the M1 and that the anatomic relationship between motor tracts and brain tumours is a critical determinant of postoperative motor function. Other considerations, including potential complications of this procedure and relative efficacy and safety versus surgery under general anaesthesia for patients with brain tumours in the M1, are discussed.

Combined movement of multi-joint muscles activates a smaller area compared to the sum of areas activated by respective single-joint muscles after restoration of paresis.

Awake surgery provides accurate localization of brain function based on rapid reversible neurological changes during surgical manipulation. In this study, hand clenching rapidly deteriorated due to surgical manipulation during awake surgery and instantly recovered not by hand clenching alone but by combined movement of hand clenching and elbow flexion. Postoperative fMRI (functional MRI) showed a smaller area activated by combined movement of hand clenching and elbow flexion than the sum of areas activated by hand clenching alone and elbow flexion alone. Conversely, the activated area by combined movement of hand clenching and elbow flexion was almost the same as the sum of areas by hand clenching alone and elbow flexion alone in fMRI of normal volunteers. These findings indicate reorganization of the motor area by combined movement including the motor function of previous transient weakness, and might suggest the effectiveness of combined movement to improve motor paresis in rehabilitation.

Damage of left temporal lobe resulting in conversion of speech to Sutra, a Buddhist prayer stored in the right hemisphere.

The present study describes a case of a right-handed 74-year-old woman with a brain tumor who showed conversion of speech to Sutra, a Buddhist prayer, which was stored in the right hemisphere according to the Wada test. After surgery, relative improvement in the speech disorder was observed, and frequency of speech production of simple normal words with normal phonology increased. These observations indicate that damage to left temporal lobe resulted in conversion of speech to Sutra, and that Sutra was stored in this patient's right hemisphere.

Deficits in the left inferior longitudinal fasciculus results in impairments in object naming.

The functional characteristics of the left inferior longitudinal fasciculus (ILF) remain unclear. The present study describes a case of a right-handed 74-year-old woman with a brain tumor who showed marked deterioration in object naming ability after invasion of the tumor into the medial region of the left posterior (middle and inferior) temporal lobe just beside the atrium of the lateral ventricle. Diffusion tensor imaging showed possible interruption of the left ILF after invasion of tumor at this site. By contrast, the left superior longitudinal fasciculus (SLF) remained intact after invasion of tumor, and the inferior fronto-occipital fasciculus (IFOF) was already disrupted prior to tumor invasion. These observations indicate that intact ILF function may be required for object naming ability.

Damage to the upper portion of area 19 and the deep white matter in the left inferior parietal lobe, including the superior longitudinal fasciculus, results in alexia with agraphia.

Analysis of lesions and symptoms in patients with brain tumors combined with information from diffusion tensor imaging provides direct evidence of the anatomical localization of brain function. Using these methods, we evaluated 8 patients who underwent surgery for metastatic brain tumors located in the left occipital lobes between 2007 and 2009. Preoperatively, 4 patients (cases 1-4) had alexia with agraphia while the other 4 patients (cases 5-8) did not. Tractography for the superior longitudinal fasciculus (SLF) was performed before surgery in case 1. The common brain tumors in cases 1-4 were located in the upper portion of area 19, and peritumor edema in that area resulted in compromise of the deep white matter of the inferior parietal lobe (IPL). The SLF was compressed and disrupted in the white matter of the IPL near the upper portion of area 19 in case 1. In cases 5-8, the brain tumors were not located in the upper portion of area 19. These results suggest that damage to the upper portion of area 19 and to the white matter in the left IPL, including the SLF, resulted in alexia with agraphia.

Relationships between brain tumor and optic tract or calcarine fissure are involved in visual field deficits after surgery for brain tumor.

PURPOSE: Diffusion tensor tractography provides useful information regarding the surgical strategy for brain tumors. The goal of the present study was to analyze relationships between visual field deficits and the locations of brain tumors compared with optic tracts as visualized by tractography, and compared with the calcarine fissure. METHODS: Subjects comprised 11 patients with brain tumor in the occipital lobe or atrium of the lateral ventricle who underwent surgery between October 2006 and February 2009. Tumors were categorized as Type A, with almost all the optic tract in the occipital lobe or atrium of the lateral ventricle running close to and stretched by the brain tumor; and Type B, with the optic tract running at least partially distant to the brain tumor and remaining unstretched. RESULTS: Those type A optic tracts that were laterally compressed by brain tumors (Cases 1-3) displayed hemianopsia after surgery. When the brain tumor was located rostro-medial to the calcarine fissure and optic tracts were compressed caudally by the tumor, lower quadrant hemianopsia remained after surgery (Cases 4, 5). In other cases, the visual field remained or improved to normal after surgery. CONCLUSION: The relationship between optic tracts or the calcarine fissure, and brain tumors in the occipital lobe or atrium of the lateral ventricle is related to visual field deficits after surgery. In particular, those Type A optic tracts that are compressed laterally show hemianopsia of the visual field after surgery.

Awake surgery with continuous motor testing for resection of brain tumors in the primary motor area.

Resection of brain tumors in the primary motor area (M1) is difficult to achieve without adversely affecting motor function. Between November 2003 and November 2006, 16 patients with 18 brain tumors involving the M1 (11 metastatic, 6 gliomas, 1 cavernous angioma) underwent craniotomy and awake surgery with continuous motor testing at our hospital. Patients were classified as either type A (9 patients), indicating that motor tracts ran in close proximity to the brain tumors, or type B (7 patients), indicating that motor tracts ran distant to the tumor. The relationship between the extent of resection and post-operative motor function was subsequently evaluated. In 17 out of 18 cases, final post-operative motor function was either preserved or improved relative to pre-operative levels, although transient deterioration of motor function and partial removal of the tumor were observed in 7 and 8 cases, respectively. The remaining patients experienced slight deterioration in motor function of the upper extremities. All type A patients experienced suboptimal outcomes, involving transient or permanent deterioration of motor function after surgery or only partial removal of the tumor. By contrast, most type B patients experienced good outcomes (no deterioration of motor function and gross total removal of the tumor). In conclusion, awake surgery with continuous motor testing allowed for resection of brain tumors in the M1 and preservation of motor function, although the patients in whom motor tracts ran in close proximity to the tumors experienced suboptimal outcomes.

Corticospinal tract extraction combining diffusion tensor tractography with FMRI in patients with brain diseases.

PURPOSE: Our goal was to visualize diffusion tensor tractography (DTT) of the corticospinal tract (CST) with areas of activation on functional magnetic resonance imaging (fMRI) to acquire useful, highly accurate preoperative information. We investigated the usefulness of the technique and our method of precisely evaluating the depicted DTT in patients with brain disease. MATERIALS AND METHODS: Nineteen subjects underwent 3-dimensional T(1)-weighted imaging for anatomical reference; gradient-echo, echo-planar imaging (EPI) for fMRI; and single-shot, diffusion-weighted EPI for DTT. The target point for DTT was placed within activated areas in the primary motor area on fMRI, and the seed point was placed in the cerebral peduncle. DTT was depicted with the seed and target points. We examined the precision of DTT using this method by assessing the anteroposterior relationship of depicted DTTs of the upper and lower extremities in the posterior limb of the internal capsule. RESULTS: DTT was depicted in 18 of 19 cases of the upper extremity and in 12 of 19 cases of the lower extremity. In the evaluation of precision, DTT reflected the posterior limb of the internal capsule in all cases. In terms of the anteroposterior relationship of DTTs, nine of 12 cases showed that fibers in the upper extremities passed in front of fibers in the lower extremities. CONCLUSION: This technique allows depiction of DTT associated with a local brain function in the CST in patients with brain disease and may be useful for operative planning. Our method of evaluating precision is also likely to prove useful.

Volumetric q-space imaging by 3D diffusion-weighted MRI.

High b-value diffusion magnetic resonance imaging (MRI) enables us to detect far smaller architectures, by using q-space analysis, than the resolution in conventional MRI. Average displacement, one of the q-space parameters, quantitatively reflects architecture size and is very useful in observing small changes in microstructures in vivo (e.g., neurodegeneration, tumor heterogeneity, and others). Diffusion-weighted imaging (DWI) is performed by a two-dimensional (2D) multislice method; however, due to finite slice thickness and slice gap, there is a partial-volume effect that makes it difficult to detect the net q-space signal. On the other hand, three-dimensional (3D) MRI, having the advantages of very thin slice thickness and no slice gap (contiguous slices), allows volumetric evaluation acquired in a small isotropic voxel, as compared to 2D multislice imaging. Little is known about the isotropic high-resolution 3D DWI application to q-space analysis. In this study, we have developed and implemented a high b-value 3D DWI sequence, applied q-space analysis to study the reliability of high b-value 3D DWI and obtained a microscopic analytical map with isotropic high resolution and less contamination.

Mirror therapy activates outside of cerebellum and ipsilateral M1.

Mirror therapy is effective in the rehabilitation of patients with hemiparesis, but its mechanism is not clear. In this study, a patient with brain tumor (patient 1) who underwent mirror therapy after surgery and showed drastic recovery of hand paresis, a patient with visual memory disturbance (patient 2), and five normal volunteers performed tasks related to mirror therapy in fMRI study. In patient 1 and all normal volunteers, right and left hand clenching with looking at a mirror (eye open) activated outside of cerebellum, while right and left hands clenching with eye closed activated inside of cerebellum. In patient 2, mirror therapy did not activate outside of cerebellum. In patient 1, and 3 out of 5 normal volunteers, the area of right (affected) M1 activated by right and left hands clenching with eye open was more than that by right and left hands clenching with eye closed, and that right M1 was activated by right hand clenching with eye open. In conclusion, mirror therapy facilitate the paresis of patients by activating ipsilateral M1 and outside of cerebellum, which is possibly related to visual memory function.

Operative Strategies during Awake Surgery Affect Deterioration of Paresis a Month after Surgery for Brain Lesions in the Primary Motor Area.

Introduction We analyzed factors associated with worsened paresis at 1-month follow-up in patients with brain tumors located in the primary motor area (M1) to establish protocols for safe awake craniotomy for M1 lesions. Methods Patients with M1 brain tumors who underwent awake surgery in our hospital (n = 61) were evaluated before, during, and immediately and 1 month after surgery for severity of paresis, tumor location, extent of resection, complications, preoperative motor strength, histology, and operative strategies (surgery stopped or continued after deterioration of motor function). Results Worsened paresis at 1-month follow-up was significantly associated with worsened paresis immediately after surgery and also with operative strategy. Specifically, when motor function deteriorated during awake surgery and did not recover within 5 to 10 minutes, no deterioration was observed at 1-month follow-up in cases where we stopped surgery, whereas 6 of 13 cases showed deteriorated motor function at 1-month follow-up in cases where we continued surgery. Conclusion Stopping tumor resection on deterioration of motor function during awake surgery may help prevent worsened paresis at 1-month follow-up.

Cerebral networks for spontaneous and synchronized singing and speaking.

Singing in unison is usually easier than singing alone, but the neural mechanism underlying these two contrasting modes of singing remains unknown. We investigated neural correlates of singing by a functional magnetic resonance imaging study focusing on the capacities of spontaneity and synchronization and compared them with those of speaking. The left inferior frontal gyrus appears important for self-generation of text in singing and speaking without auditory input, whereas the left posterior planum temporale plays a key role in synchronizing both text and melody, in combination with the bilateral inferior parietal lobule for singing along, and with the left angular gyrus for speaking in chorus. These findings indicate that text and melody are not processed symmetrically or parallel in singing a well-learned song.

Gene expression profile of long-lived Ames dwarf mice and Little mice.

Ames dwarf mice (Prop1df/df) and Little mice (Ghrhrlit/lit) are used as models of delayed aging and show significant increases in lifespan (50% and 25%, respectively) when compared with their wild-type siblings. To gain further insight into the molecular basis for the extended longevity of these mice, we used oligonucleotide microarrays to measure levels of expression of over 14 000 RNA transcripts in liver during normal aging at 3, 6, 12 and 24 months. We found that the Prop1df/df and Ghrhrlit/lit genotypes produce dramatic alterations in gene expression, which are predominantly maintained at all ages. We found 1125 genes to be significantly affected by the Prop1df/df genotype and 1152 genes were significantly affected by the Ghrhrlit/lit genotype; 547 genes were present in both gene lists and showed parallel changes in gene expression, suggesting common mechanisms for the extended longevity in these mutants. Some of the functional gene classes most affected in these mutants included: amino acid metabolism, TCA cycle, mitochondrial electron transport, fatty acid, cholesterol and steroid metabolism, xenobiotic metabolism and oxidant metabolism. We found that the Prop1df/df genotype, and to a minor extent the Ghrhrlit/lit genotype, also produced complex alterations in age-dependent changes in gene expression as compared with wild-type mice. In some cases these alterations reflected a partial delay or deceleration of age-related changes in gene expression as seen in wild-type mice but they also introduced age-related changes that are unique for each of these mutants and not present in wild-type mice.

Realtime ultrasound screening by satellite telecommunication.

Realtime ultrasound screening was carried out using a medical examination vehicle equipped with a diagnostic ultrasound scanner and a satellite telecommunication system. Screening was performed on 205 residents in a rural community in Japan and consisted of 57 cardiac, 57 abdominal, 60 thyroid and 31 breast ultrasound scans. The resolution of the realtime ultrasound images sent via communications satellite at 1.5 Mbit/s was almost identical to that of the original images taken by the ultrasound scanner. A disorder was diagnosed in 11 (19%) of the cardiac examinations, 28 (49%) of the abdominal, 19 (32%) of the thyroid and 7 (23%) of the breast examinations. Although some technical problems occurred, ultrasound screening by telemedicine appears to be a promising technique for those who live in rural communities.

Characteristics of diffusion-weighted stimulated echo pulse sequence in human skeletal muscle.

The aim of our study was to simulate an effective diffusion-weighted imaging (DWI) pulse sequence and to evaluate the best b value in skeletal muscle. The evaluated pulse sequences were spin echo (SE), stimulated echo (STE), and gradient-recalled echo (GRE). The signal intensity changed in some DWI pulse sequences when the b value was changed. Moreover, the static magnetic field of 1.5 T was compared with that of 3.0 T. Next, diffusion tensor imaging of the human skeletal muscle was measured. The experimental subjects were healthy male volunteers (n = 7; age 21.8 ± 1.1 years). We changed the b value in steps of 100 s/mm(2) from 0 to 2000 s/mm(2), and the diffusion values [fractional anisotropy (FA), λ(1), λ(2), and λ(3)] were calculated based on the data. The STE method could maintain signals up to b values of 1300 s/mm(2), but the SE and GRE methods suffered from high noise. In the human study, the mean FA (±SD) was 0.41 ± 0.02 in the tibialis anterior muscle (TA) and 0.31 ± 0.02 in the soleus muscle (SOL) at a b value of 1000 s/mm(2). The correlation of the FA with the b value coefficient and the P value by Student's t test were r = 0.981 and P < 0.001 for the TA and r = 0.982, P < 0.001 for the SOL. However, the FA became high with a low b value. In conclusion, STE was very useful for DWI in a short T (2)-value tissue. Moreover, a minimum b value of 800 s/mm(2) was necessary for evaluation of human skeletal muscle.