The Clinical Feasibility of Using Non-Breath-Hold Real-Time MR-Echo Imaging for the Evaluation of Mediastinal and Chest Wall Tumor Invasion

OBJECTIVE: We wanted to determine the clinical feasibility of using non-breath-hold real-time MR-echo imaging for the evaluation of mediastinal and chest wall tumor invasion. MATERIALS AND METHODS: MR-echo imaging was prospectively applied to 45 structures in 22 patients who had non-small cell lung cancer when the tumor invasion was indeterminate on CT. The static MR imaging alone, and the static MR imaging combined with MR-echo examinations were analyzed. The surgical and pathological findings were compared with using the Wilcoxon-signed rank test and McNemar's test. RESULTS: The accuracy, sensitivity and specificity of the combined MR-echo examination and static MR imaging for determining the presence of invasion were 84%, 83% and 85%, respectively, for the first reading session and they were 87%, 83% and 87%, respectively, for the second reading session (there was substantial interobserver agreement, k = 0.74). For the static MR imaging alone, these values were 62%, 83% and 59%, respectively, for the first reader and they were 69%, 67% and 74%, respectively, for the second reader (there was moderate interobserver agreement, k = 0.49). The diagnostic confidence for tumor invasion was also higher for the combined MR-echo examination and static MR imaging than that for the static MR imaging alone (p < 0.05). CONCLUSION: The combined reading of a non-breath-hold real-time MR-echo examination and static MR imaging provides higher specificity and diagnostic confidence than those for the static MR imaging reading alone to determine the presence of mediastinal or chest wall tumor invasion when this was indeterminate on CT scanning.

Language Lateralization by Functional MRI: A Comparison with Wada Test-preliminary Results

PURPOSE: To evaluate the usefulness of functional MR imaging (fMRI) for the determination of languagedomi-nance and to assess differences in language lateralization according to activation task or activated area. MATERIALS AND METHODS: Functional maps of the language area were obtained during word generation tasks (noun andverb) and a reading task in ten patients (9 right handed, 1 left handed) who had undergone the Wada test. MRexaminations were performed using a 1.5T scanner and the EPI BOLD technique. The SPM program was employed for thepostprocessing of images and the threshold for significance was set at p<0.001 or p<0.01. A lateralization indexwas calculated from the number of activated pixels in three hemispheric re-gions (whole hemisphere, frontal lobe,and temporoparietal lobe), and the results were compared with those of Wada tests. The results for lateralizationof language area were compared among stimulation tasks and regions and used for calculation of lateralizationindices. RESULTS: During the Wada test, nine patients were left dominant and one patient was right dominant forlan-guage. Language dominance based on activated signals in each hemisphere was consistent with the results of theWada test in 87.5% (verb and noun generation tasks) and 90% (reading task) of patients. Language domi-nancedetermined by activated signals in the frontal lobe was consistent in 87.5%, 75%, and 80% of patients in eachstimulation task (verb generation, noun generation, and reading), respectively. The consistency rate of ac-tivatedsignals in the temporoparietal lobe was 87.5%, 87.5% and 80% of patients in each task. The mean val-ue of thelateralization index, calculated on the basis of activated signals in the temporoparietal lobe was higher thanthat in the hemisphere or frontal lobe. The verb generation task showed a higher lateralization index than thenoun generation or reading task. CONCLUSION: The lateralization index was higher in the verb generation task andin the region of the tem-poroparietal lobe than in other stimulation tasks or regions. fMRI is a potentiallyuseful non-invasive method for the determination of language dominance.

A Study on the Activation of Supplementary Motor Area in Functional Magnetic Resonance Imaging of the Brain

PURPOSE: To evaluate the activated zone of the supplementary motor area through motor and sensorystimula-tion of both hands by fMRI. MATERIALS AND METHODS: Twenty-four healthy volunteers, ranging in age from 20to 30 years, served as sub-jects. They were divided into four groups and performed one of the four activationtasks : complex movement, fine movement, touch sensation, heat sensation. Complex movement consisted of a fingertask in which sub-jects flexed and extended all fingers repeatedly in union, without the fingers touching eachother(group I). Fine movement involved a thumb task in which subjects flexed and extended the thumb repeatedlywithout touch-ing the other fingers(group II). Touch sensation consisted of a palm task in which another personrepeatedly drew a circle on the subject 's palm (group III), and heat sensation involved of a palm task in whichsubject 's palm was touched by another person with a 40 degreeC water-bag (group IV). F-MRI was conducted on acommer-cial 1.5-T scanner equipped with echo-planar imaging. After overlapping images were obtained using aZ-s-core, and the mean/curve in the MR devices was evaluated, the activated zone of the supplementary motor RESULTS: Thirty-two of 48 images(20 of the 24 men) revealed activated zones in the supplementary motor area. Ingroup I, activation was observed in five subjects, in three of whom it was bilateral (contralateral activation).In group II, activation was observed in five subjects, in one of whom it was bilateral. In group III, activationoccurred in five subjects(bilateral in four, and contralateral in three), and In group IV, activation was alsoob-served in five ; in three of these it was bilateral. CONCLUSION: Using fMRI, and in association with motor andsensory tasks, the supplementary motor area was activated in 66.7% of healthy volunteers (32/48).

Functional MRI of Motor Speech Area Combined with Motor Stimulation during Resting Period

PURPOSE: To evaluate functional MR imaging of the motor speech area with and without motor stimulation duringthe rest period. MATERIALS AND METHODS: Nine healthy, right-handed volunteers(M:F=7:2, age:21-40years) wereincluded in this study. Brain activity was mapped using a multislice, gradient echo single shot EPI on a 1.5T MRscanner. The paradigm consisted on a series of alternating rest and activation tasks, performed six times. Each volunteer in the first study(group A) was given examples of motor stimulation during the rest period, while eachin the second study(group B) was not given examples of a rest period. Motor stimulation in group A was achieved bycontinuously flexing five fingers of the right hand. In both groups, maximum internal word generation was achievedduring the activation period. Using fMRI analysis software(Stimulate 5.0) and a cross-correlationmethod(background threshold, 200; correlation threshold, 0.3; ceiling, 1.0; floor, 0.3; minimal count, 3),functional images were analysed. After correlating the activated foci and a time-signal intensity curve, theactivated brain cortex and number of pixels were analysed and compared between the two tasks. The t-test was usedfor statistical analysis. RESULT: In all nine subjects in group A and B, activation was observed in and adjacentto the left Broca's area. The mean number of activated pixels was 31.6 in group A and 27.8 in group B, adifference which was not statistically significant(P>0.1). Activities in and adjacent to the right Broca 's areawere seen in seven of group A and four of group B. The mean number of activated pixels was 14.9 in group A and 18in group B. Eight of nine volunteers in group A showed activity in the left primary motor area with negativecorrelation to the time-signal intensity curve. The mean number of activated pixels for this group was 17.5. Inthree volonteers, activation in the right primary motor area was also observed, the mean number of activatedpixels in these cases was 10.0. CONCLUSION: During the rest period, functional MR imaging of the motor speechcenter combined with motor stimulation was more effective than that without stimulation, and simultaneouslyprovided mapping of the primary motor area.

Functional MR Imaging of Cerebral Auditory Cortex with Linguistic

PURPOSE: To obtain preliminary data for understanding the central auditory neural pathway by means of functional MR imaging (fMRI) of the cerebral auditory cortex during linguistic and non-linguistic auditory stimulation. MATERIALS AND METHODS: In three right-handed volunteers we conducted fMRI of auditory cortex stimulation at 1.5 T using a conventional gradient-echo technique (TR/TE/flip angle: 80/60/40 degree). Using a pulsed tone of 1000 Hz and speech as non-linguistic and linguistic auditory stimuli, respectively, images-including those of the superior temporal gyrus of both hemispheres-were obtained in sagittal plases. Both stimuli were separately delivered biaurally or monoaurally through a plastic earphone. Images were activated by processing with homemade software. In order to analyze patterns of auditory cortex activation according to type of stimulus and which side of the ear was stimulated, the number and extent of activated pixels were compared between both temporal lobes. RESULTS: Biaural stimulation led to bilateral activation of the superior temporal gyrus, while monoaural stimulation led to more activation in the contralateral temporal lobe than in the ipsilateral. A trend toward slight activation of the left (dominant) temporal lobe in ipsilateral stimulation, particularly with a linguistic stimulus, was observed. During both biaural and monoaural stimulation, a linguistic stimulus produced more widespread activation than did a non-linguistic one. CONCLUSION: The superior temporal gyri of both temporal lobes are associated with acoustic-phonetic analysis, and the left (dominant) superior temporal gyrus is likely to play a dominant role in this processing. For better understanding of physiological and pathological central auditory pathways, further investigation is needed.

A Comparative Study of Single and Multiple Hand Tasks Using

PURPOSE: To assess, using functional MRI and by comparing activated motor sensory areas, the independence ofbrain activation during single and alternative multiple hand tasks. MATERIALS AND METHODS: The subjects were sixhealthy volunteers. Using at 1.5T Siemens system and single shot FID-EPI sequencing(T2* weighted image;TR/TE0.96msec/61msec, flip angle 90 degrees, matrix size 96X128, slice thickness/gap 5mm/0/8mm, FOV 200mm) and T1-weightedanatomic images, functional MRI was performed. The paradigm of motor tasks consisted of appositional fingermovements; the first involved the separate use of the right, left, and both hands, while an alternative taskinvolved the use of the right, left, and both hands in sequence. Using cross-correlation method(threshold:0.6) andfMRI analysis software (Stimulate 5.0), functional images were obtained. The activated area of brain cortex, thenumber of pixel, the aberage percentage change in signal intensity, and correlation of the time-signal intensitycurve in the activated motor area were analysed and compared between the two task groups. Statistical analysisinvolved the use of Wilcoxon signed-rank test. RESULTS: It was seen on fMRI that durina both single andalternative motor tasks, the same areas were consistently activated; in four volunteers, most activation occurredin the contralateral primary motor area. Between the two task methods, the average change in the number ofactivated pixels was 12.3+/-5%, but the difference was not statistically significant(P>0.1). Increased signalintensity in the alternative task group(7.48+/-1.22%) was more statistically significant than in the single taskgroup(5.77+/-0.9%)(p<.001). With regard to the time-intensity curve, there was significant correlation between thetwo groups(0.87+/-0.07). CONCLUSION: Brain activation did not differ according to whether the motor task wassingle or alternative. We therefore suggest that during multiple stimuli, the relevant functional areas andneuronal column are activated independently.