An optimized workflow for the integration of biological information into radiotherapy planning: experiences with T1w DCE-MRI.

Planning of radiotherapy is often difficult due to restrictions on morphological images. New imaging techniques enable the integration of biological information into treatment planning and help to improve the detection of vital and aggressive tumour areas. This might improve clinical outcome. However, nowadays morphological data sets are still the gold standard in the planning of radiotherapy. In this paper, we introduce an in-house software platform enabling us to combine images from different imaging modalities yielding biological and morphological information in a workflow driven approach. This is demonstrated for the combination of morphological CT, MRI, functional DCE-MRI and PET data. Data of patients with a tumour of the prostate and with a meningioma were examined with DCE-MRI by applying pharmacokinetic two-compartment models for post-processing. The results were compared with the clinical plans for radiation therapy. Generated parameter maps give additional information about tumour spread, which can be incorporated in the definition of safety margins.

[MR-based methods of the functional imaging of the central nervous system]. / MR-basierte Methoden der funktionellen Bildgebung des zentralen Nervensystems.

This review presents the basic principles of functional imaging of the central nervous system utilizing magnetic resonance imaging. The focus is set on visualization of different functional aspects of the brain and related pathologies. Additionally, clinical cases are presented to illustrate the applications of functional imaging techniques in the clinical setting. The relevant physics and physiology of contrast-enhanced and non-contrast-enhanced methods are discussed. The two main functional MR techniques requiring contrast-enhancement are dynamic T1- and T2*-MRI to image perfusion. Based on different pharmacokinetic models of contrast enhancement diagnostic applications for neurology and radio-oncology are discussed. The functional non-contrast enhanced imaging techniques are based on "blood oxygenation level dependent (BOLD)-fMRI and arterial spin labeling (ASL) technique. They have gained clinical impact particularly in the fields of psychiatry and neurosurgery.

Benign prostate hyperplasia: evaluation of treatment response with DCE MRI.

Benign prostate hyperplasia (BPH) is a major disease and its non-surgical therapy a major area of interest. The purpose of this study was to establish perfusion parameters in beagles with BPH using dynamic contrast-enhanced (DCE) MRI and to investigate changes due to the effects of finasteride treatment. Twelve male beagles (mean age 4.4 +/- 0.9,years) were divided into a control and treatment group that received a daily dose of 1 mg/kg finasteride. DCE MRI was carried out in a clinical scanner using a 3D spoiled gradient echo sequence prior to and during treatment. 0.2 mmol/kg contrast agent (gadoteridol) was administered with an injection rate of 0.2 ml/s followed by a 15 ml flush of saline. Contrast enhancement was evaluated by pharmacokinetic mapping of a two-compartment model with colour overlay images in addition to regional ROI analysis. Quantitative parameters were defined by the amplitude of contrast enhancement A, the exchange rate k(ep) and the time to maximum signal enhancement. Dynamic contrast-enhanced MRI investigations of the prostate revealed two distinct zones, an inner, periurethral zone and an outer, parenchymal zone. The periurethral zone is highly vascularized, whereas the parenchymal zone is moderately vascularized when compared to other parenchymal organs. During treatment, in the parenchymal zone the intensity of enhancement (amplitude A) and the time to maximum signal enhancement increased, while the exchange rate k(ep) decreased. Dynamic contrast-enhanced MRI of BPH reveals distinct differences between individual zones within the prostate. Moreover, changes during successful treatment suggest increased blood volume per volume of tissue and decreased vessel leakiness.

[Clinical MR at 3 Tesla: current status]. / Klinische MRT bei 3 Tesla: Aktueller Stand.

Clinical MRI is mostly performed at field strengths up to 1.5 Tesla (T). Recently, approved clinical whole-body MR-systems with a field strength of 3 T became available. Its installation base is more rapidly growing than anticipated. While site requirements and operation of these systems do not differ substantially from systems with lower field strength, there are differences in practical applications. Imaging applications can use the gain in signal-to-noise for increased spatial resolution or gain in speed. This comes at a trade off in increased sensitivity to field inhomogeneities and changes in relaxation times, which lead to changes in image contrast. The benefit of high field for spectroscopy consists in increased signal-to-noise-ratio and improvement in frequency resolution. The increase in energy deposition necessitates the use of special strategies to reduce the specific absorption rate (SAR). This paper summarizes the current state of MR at 3 T.

[Clinical high- and ultrahigh-field MR and its interaction with biological systems]. / Klinische Hoch- und Ultrahochfeld-MR und ihre Wechselwirkung mit biologischen Systemen.

The field strength of the static field in MRI has increased from 0.015 to 12 Tesla (T) during the last 25 years, which is about an 800 fold increase. In addition to low- and high field systems (1.5-4 T), ultra-high field systems with field strengths above 4 T are now available for human MRI. The extension of non-significant risk status for clinical fields up to 8 T by the FDA in July 2003 facilitates the further growth of this technology. The increase in field strength creates the need for a better understanding of the safety challenges to ensure safety for human imaging applications. This encompasses understanding the effects of the strong magnetic field at the atomic and molecular level and from biological tissue to organ systems. Moreover, in addition to the effects of a static magnetic field, the effects of radio-frequency- and gradient-fields have to be considered. This paper reviews the safety relevant issues for high- and ultrahigh field MR.

[Event-related functional magnetic resonance imaging of cerebral pain processing]. / Ereigniskorrelierte funktionelle Magnetresonanztomographie zur Erforschung der zerebralen Schmerzverarbeitung.

Neurofunctional magnetic resonance imaging (fMRI) offers the possibility to map cerebral activity non-invasively. The development of event-related techniques during the past years allows to study brain processes with high spatial and temporal resolution. Based on these techniques, EPI- and FLASH sequences were developed in this study, to investigate cerebral processing of experimental thermal pain stimulation. Phasic and tonic stimulation paradigms were developed with an MR-compatible contact thermode. Functional mapping of pain-relevant areas was performed with these paradigms, as well as a specification of the temporal characteristics of the activation. Further, a randomized paradigm with several stimulus intensities could differentiate graded functional responses, dependent on stimulus intensity in specific "regions-of-interest". In this design, randomizing the stimulus order reduced habituation effects, while continuous subjective magnitude estimation of the stimuli kept attention of subjects maximal.

[Cerebrospinal fluid protein tau levels in the differential diagnosis of Alzheimer's disease]. / Tau-Protein-Spiegel in der Diagnostik der Alzheimer-Demenz.

Tau protein concentration in cerebrospinal fluid was determined in 55 patients with Alzheimer's disease (AD), 18 patients with vascular dementia (VD), 19 patients with dementia caused by other disorders and 14 patients with major depression. Significantly (p < 0.05) elevated protein tau concentrations were found in AD patients (564.5 +/- 275.5 pg/ml) compared to all other patient groups (VD: 406.5 +/- 263.9 pg/ml; other dementia: 275.0 +/- 135.4 pg/ml; depression: 212.9 +/- 115.6 pg/ml). However, tau levels in AD patients covered a broad range (163.2 pg/ml-1200 pg/ml). AD patients with tau levels below the 25%-percentile of the distribution (among them a high percentage of patients with presenile onset) showed tau levels similar to those of the patients with late life depression. No significant correlations between tau levels and clinical variables such as severity of dementia, age, age of onset, duration of illness, and cerebral changes as assessed by volumetric magnetic resonance imaging could be demonstrated. Similarly, we could not find an influence of either APO-E genotype or psychotropic medication on the tau levels in AD patients. In accordance with other studies our results confirm elevated tau levels in AD compared to elderly not demented control subjects. Comparing groups, this finding applies as well with respect to VD and other dementing disorders. However, elevated tau levels cannot be detected in a subgroup of AD patients. This finding needs to be further investigated in future studies.

Motor dysfunction and sensorimotor cortex activation changes in schizophrenia: A study with functional magnetic resonance imaging.

Recent studies demonstrate a diminished activation of the sensorimotor cortex and supplementary motor area (SMA) in schizophrenia which may be involved in the pathogenesis of neurological soft signs (NSS). Yet, the question whether a retarded motor performance may account for these changes remained to be clarified. Twelve DSM-III-R schizophrenics and 12 healthy controls were included. All subjects were right-handed. Nine patients received clozapine, two conventional neuroleptics, and one was drug-free. Functional magnetic resonance imaging (fMRI) was obtained in a resting condition and during pronation/supination at three speed levels (low, medium, and high) with motor performance recorded simultaneously using a pronation/supination device. While measures of motor retardation (i.e., repetition rate and amplitude of the movements) did not differ between patients and controls, the variability of performance was significantly (P < 0.05) increased in the patients' group. In addition, patients with schizophrenia showed a significantly (P < 0.05) decreased activation of the sensorimotor cortices. Similar, although nonsignificant (P = 0.09) activation changes were observed in the SMA. Activation differences were more pronounced at a slow speed and in the drug-free patient. These results confirm a diminished sensorimotor cortex and SMA activation and indicate that variability of performance rather than retarded performance per se may correspond to these changes.

Comparison of functional MR-venography and EPI-BOLD fMRI at 1.5 T.

Functional magnetic resonance imaging (fMRI) of the brain using blood oxygenation level dependent (BOLD) contrast relies on the changes of paramagnetic deoxyhemoglobin concentration, which affects brain parenchyma and draining venous vessels. These changes in deoxyhemoglobin concentration in venous vessels can also be monitored using a high-resolution susceptibility-based MR-venography technique. Four volunteers participated in the study in which functional MR-venograms were compared with conventional echo-planar imaging (EPI)-BOLD-fMRI. In all cases, small venous vessels could be identified close to the areas of activation detected by conventional fMRI. In the venograms, task performance (finger tapping) resulted in a loss of venous vessel contrast compared to the resting state, which is consistent with a local decrease of deoxyhemoglobin concentration. MR-venography allows a direct visualization of the BOLD-effect at high spatial resolution. In combination with conventional fMRI, this technique may help to separate the contribution of brain parenchyma and venous vessels in fMRI studies.

In vivo quantification of brain volumes in subcortical vascular dementia and Alzheimer's disease. An MRI-based study.

Quantitative magnetic resonance imaging (MRI) was used to assess global and regional cerebral volumes in patients with a clinical diagnosis of subcortical vascular dementia (VD) and Alzheimer's disease (AD). Whole brain volume, cerebrospinal fluid volume, volumes of the temporal, frontal and parietal lobes, the cerebellum and the amygdala-hippocampus complex were determined using a personal computer-based software. Seventeen patients with VD, 22 patients with AD and 13 healthy controls were included. Analysis of covariance using age as covariate demonstrated significant mean differences between controls and dementia groups with respect to all morphological parameters. However, apart from the volume of the cerebellum no significant volumetric differences were found between VD and AD. These results indicate that MRI-based volumetry allows differentiation between AD or VD from normal controls and that measurement of cerebellar volume may be of use to separate vascular and degenerative dementia. However, since the distribution of cerebral atrophy in both dementia groups is very similar, it is suggested that the atrophic changes are not specific to the underlying cause but rather reflect the selective vulnerability of neuronal structures.

Functional MR imaging of visual and motor cortex stimulation at high temporal resolution using a FLASH technique on a standard 1.5 Tesla scanner.

Functional magnetic resonance imaging (fMRI) was performed on a conventional 1.5 T scanner by means of a modified FLASH-technique at temporal resolutions of 80 and 320 ms. The method's stability was assessed by phantom measurements and by investigation of three volunteers resulting in a low amplitude (3%) periodic (4 s) signal modulation for the in vivo measurements, which was not observable in the phantom experiments. fMRI activation studies of motor and visual cortices of four adjacent slices were carried out on 12 healthy right-handed volunteers. Stimulation was performed by a triggered single white light flash or single finger-to-thumb opposition movement, respectively. Event-related response of visual and motor activation was traced over 10.24 s with a temporal resolution of 320 ms for the four slice measurements. Brain activation maps were calculated by correlation of measured signal time course with a time-shifted boxcar function. Activation was quantified by calculation of percentual signal change in relation to the baseline. Observed signal magnitudes were about 5-7% in visual and about 8-12% in primary motor cortex. While photic response was delayed by about 2 s, motor stimulation showed an instantaneous increase of the MR signal. MR signal responses for both stimuli had decayed completely after about 5 s. Our results show that event-related fMRI enables mapping of brain function at sufficient spatial resolution with a temporal resolution of up to 80 ms on a conventional scanner.

Functional magnetic resonance imaging in a stereotactic setup.

The localization of critical structures within the brain is important for the planning of therapeutic strategies. Functional MRI is capable to assess functional response of cortical structures to certain stimuli. The authors present two techniques for functional MRI (fMRI) in a stereotactic set-up. The skull of the patients has been immobilized for stereotactic treatment planning either with a self developed stereotactic ceramic frame and bony fixation or with an individual precision mask system made of light cast. It has been shown that this frame does not produce any image distortion. fMRI was performed using a modified FLASH sequence on a conventional 1.5 T MRI scanner with a specially developed linear polarized head coil. The imaging technique used was an optimized conventional 2D and 3D, first order flow rephased, gradient echo sequence (FLASH) with fat-suppression and reduce bandwidth (16-28 Hz/pixel) and TR = 80-120 ms, TE = 60 ms, flip angle = 40 degrees, matrix = 128 x 128, FOV = 150-250 mm, slice-thickness = 2-5 mm, NEX = 1, and a total single scan time for one image of about 7 sec. The motor cortex stimulation was achieved by touching each finger to thumb in a sequential, self-paced, and repetitive manner. Statistical parametric maps based on student's test were calculated. Pixels with a highly significant signal increase (p < 0.001) are overlaid on T1w SE images. The primary motor and sensory cortex could be visualized with this method in all 10 patients that were imaged in this study. Due to tight fixation of the patient's skull there have been no motion artifacts. These results show that functional MRI is feasible in an stereotactic set-up with an standard 1.5 T scanner. This is a prerequisite for the exact pre therapeutic assessment of the function of cortical centers.

Improved target volume definition in radiosurgery of arteriovenous malformations by stereotactic correlation of MRA, MRI, blood bolus tagging, and functional MRI.

In this methodological paper the authors report the stereotactic correlation of different magnetic resonance imaging (MRI) techniques [MR angiography (MRA), MRI, blood bolus tagging (STAR), and functional MRI] in 10 patients with cerebral arteriovenous malformations (AVM) and its application in precision radiotherapy planning. The patient's head was fixed in a stereotactic localization system that is usable at the MR and the linear accelerator installations. By phantom measurements different materials (steel, aluminium, titanium, plastic, wood, ceramics) used for the stereotactic system were tested for mechanical stability and geometrical MR image distortion. All metallic stereotactic rings (closed rings made of massive metal) led to a more or less dramatic geometrical distortion and signal cancellation in the MR images. The best properties-nearly no distortion and high mechanical stability-are provided by a ceramic ring. If necessary, the remaining geometrical MR image distortion can be "corrected" (reducing displacements to the size of a pixel) by calculations based on modeling the distortion as a fourth-order two-dimensional polynomial. Using this method multimodality matching can be performed automatically as long as all images are acquired in the same examination and the patient is sufficiently immobilized. Precise definition of the target volume could be performed by the radiotherapist either directly in MR images or in calculated projection MR angiograms obtained by a maximum-intensity projection algorithm. As a result, information about the hemodynamics of the AVM was provided by a three-dimensional (3D) phase-contrast flow measurement and a dynamic MRA with the STAR technique leading to an improved definition of the size of the nidus, the origin of the feeding arteries, and the pattern of the venous drainage. In addition, functional MRI was performed in patients with lesions close to the primary motor cortex area leading to an improved definition of structures at risk for high-dose application in radiosurgery. The different imaging techniques of MR provide a sensitive, noninvasive, 3D method for defining target volume, critical structures, and for calculating dose distributions for radiosurgery of cerebral arteriovenous malformations, because dose calculation of radiosurgery at sufficient accuracy can be based on 3D MR data of the geometrical conformation of the patient's head.

Monitoring of task performance during functional magnetic resonance imaging of sensorimotor cortex at 1.5 T.

Functional magnetic resonance imaging (fMRI) has found widespread clinical interest. Difficulties in clinical use of the fMRI technique arise, considering the lack of knowledge about activation task performance. This accounts especially for sensorimotor activation studies, in which performance of the sensorimotor activation task is-if at all-usually rated visually by subjective or semiquantitative methods (i.e., defining categories of performance such as neurological soft signs scales). Recently, instrumental methods for the measurement and analysis of motor performance have been developed. Pronation/supination (hand rotation) movement was shown to be an easily measurable and promising motor task. We have adapted a mechanic device (pronation/supination device, PSD) to monitor motor performance during the fMRI experiment. In a feasibility study, an investigation of fMRI activation strength dependence of sensorimotor cortices and supplementary motor area upon task frequency (25, 50, and 75 cycles/min) was carried out on 10 right-handed healthy volunteers. Furthermore, the authors report the observation of stimulus-induced activation changes in the cerebellum during pronation/supination movement.

Sensorimotor cortex and supplementary motor area changes in schizophrenia. A study with functional magnetic resonance imaging.

BACKGROUND: Neurological soft signs (NSS) such as a disturbed finger-to-thumb opposition are frequently found in schizophrenia. To identify the underlying cerebral changes we investigated sensorimotor cortex and supplementary motor area (SMA) activation during finger-to-thumb opposition using functional magnetic resonance imaging (fMRI). METHOD: Ten DSM-III-R schizophrenics and seven healthy controls were included. All subjects were right-handed. fMRI was carried out in a resting condition followed by an activation state (finger-to-thumb opposition) and the activities in the sensorimotor cortices and SMA recorded. RESULTS: All subjects showed a significant activation of the SMA and both ipsilateral and contralateral sensorimotor cortices. In the controls, ipsilateral finger-to-thumb opposition was associated with a greater left than right hemispheric sensorimotor cortex coactivation. When compared with the healthy controls, the schizophrenic patients showed a decreased activation of both sensorimotor cortices and SMA, as well as a reversed lateralisation effect. CONCLUSION: Sensorimotor cortex and SMA dysfunction are associated with motor disturbances in schizophrenia.

[Functional magnetic resonance tomography of movement disorders in patients with schizophrenia]. / Funktionelle Magnetresonanztomographie (fMRT) bei Bewegungsstörungen von Patienten mit Schizophrenie.

UNLABELLED: Neurological soft signs (NSS), which are minor motor and sensory deficits, e.g., during finger-to-thumb opposition, are frequently found in schizophrenia. The purpose of this study was to investigate differences in the cerebral activation pattern in ten schizophrenic patients and ten healthy volunteers using functional MRI. METHODS: fMRI was performed using a modified FLASH sequence (TR/TE/alpha = 100/60/40 degrees) and a conventional 1.5 T MR scanner. Color-coded statistical parametric maps based on Student's t-test were calculated. Activation strength was quantified using a 5 x 6 grid over-lay. RESULTS: The volunteers showed a higher activation strength during left hand movement compared to right hand movement. This lateralization effect was reversed in patients who showed overall reduced activation strength. CONCLUSIONS: Disturbed interhemispheric balance in schizophrenic patients during motor task performance can be demonstrated using fMRI. These findings support the hypothesis that changes in the sensorimotor cortex may be involved in the development of NSS.

Postprocessing of functional MRI data of motor cortex stimulation measured with a standard 1.5 T imager.

Functional magnetic resonance imaging (fMRI) is usually based on acquisition of alternating series of images under rest and an activation task (stimulus). Brain activation maps can be generated from fMRI data sets by applying several mathematical methods. Two methods of image postprocessing have been compared: (i) simple difference of mean values between rest and stimulation, and (ii) Student's t-test. The comparison shows that the difference method is very sensitive to arbitrary signal fluctuations as seen mainly in large vessels (e.g., in the sagittal sinus), leading to insignificantly activated spots in brain activation maps. In contrary, Student's t-test maps show strongly reduced sensitivity for fluctuations and have the advantage of giving activation thresholds by setting significance levels. This allows the comparison of activation strength between patient collectives by using a grid overlay technique leading to an observer independent quantification of the stimulation effects. The method was able to reproduce previous findings of activation differences between healthy volunteers and schizophrenic patients. Moreover, a simple algorithm for the correction of slight head movements during the functional imaging task is presented. The algorithm is based on shifting the fMRI data set relative to a reference image by maximizing the linear correlation coefficients. This leads to a further reduction of insignificant brain activation and to an improvement in brain activation map quality.

Event-related functional MR imaging of visual cortex stimulation at high temporal resolution using a standard 1.5 T imager.

The authors report the technical feasibility of measuring event-related changes in blood oxygenation for studying brain function in humans at high temporal resolution. Measurements were performed on a conventional whole-body 1.5 T clinical scanner with a nonactive-shielded standard gradient system of 1 ms rise time for a maximum gradient strength of 10 mT/m. The radiofrequency (RF) transmitting and receiving MR unit consists of a commercially available circular polarized head coil. Magnet shimming with all first-order coils was performed to the volunteer's head resulting in a magnetic field homogeneity of about 0.1-0.2 ppm. The measuring sequence used was a modified 3D, first-order flow rephased, FLASH sequence with reduced bandwidth = 40 Hz/pixel, TR = 80 ms, TE = 56 ms, flip angle = 40-50 degrees, matrix = 64 x 128, field-of-view = 200-250 mm2, slice thickness = 4 mm, NEX = 1,128 partitions, and a total single scan time of about 10 min. In this sequence the 3D gradient table was removed and the 3D partition-loop acts as a time-loop for sequential measurement of 128 or 32 consecutive images at the same slice position. This means that event-related functional MRI could be performed with an interscan delay of 80 ms for a series of 128 sequential images or with an interscan delay of 320 ms for a simultaneous measurement of four slices with a series of 32 sequential images for each slice. We used a TTL signal given by the gradient board at the beginning of every line-loop in the measuring sequence and a self-made "TTL-Divider-Box" for the event triggering. This box was used to count and scale down the TTL signals by a factor of 128 and to trigger after every 128th TTL signal a single white flash-light, which was seen by the volunteer in the dark room of the scanner with a period of 10.24 s. As a consequence, the resulting event-related scan data coincide at each line of the series of 128 sequential images, which were repeated in 128 x 80 ms or 32 x 320 ms for the single- or four-slice experiment, respectively. Visual cortex response magnitude measured was about 5-7% with an approximate Gaussian shape and a rise time from stimulus onset to maximum of about 3-4 s, and a fall time to the baseline of about 5-6 s after end of stimulus. The reported data demonstrate the feasibility of functional MRI studies at high temporal resolution (up to 80 ms) using conventional MR equipment and measuring sequence.

Functional magnetic resonance imaging at 1.5 T: activation pattern in schizophrenic patients receiving neuroleptic medication.

Activation of the cerebral cortex during motor task performance can be visualised with functional MRI. A modified FLASH sequence (TR/TE/alpha 100/60/40 degrees, first order flow rephased, fat suppression, reduced bandwidth 28 Hz/pixel, 120 repetitions, three cycles of rest and finger movement for each hand) on a standard 1.5 T clinical imager was used to investigate 10 schizophrenic patients receiving clozapine and 10 healthy volunteers. All subjects were right-handed. Color-coded statistical parametric maps (SPM) based on the Student's t-test were calculated. A grid overlay was used for global and regional quantification. Activation strength was defined as the mean t-value of the respective region. All patients and volunteers showed a significant activation in the contralateral and ipsilateral sensorimotor cortex during motor task performance. The schizophrenic patients showed a significantly reduced global activation strength compared with healthy volunteers (p < .005). Selective evaluation of left-hand compared to right-hand movement demonstrated an increase in global activation strength in volunteers in contrast to a decrease in patients. Furthermore a reduced coactivation in the dominant left hemisphere was found in patients compared to volunteers during movement of the ipsilateral (left) hand. We conclude that alterations of the right and left hemispheric balance can be detected in schizophrenic patients using functional MRI at 1.5 T. These changes may indicate a disturbed interhemispheric interaction in schizophrenia. The reduction in cortical activation may result from several causes, however, taken together with previous studies and the underlying physiological effects, the most likely explanation is a combined effect of the disease and the neuroleptic medication.

Functional 2D and 3D magnetic resonance imaging of motor cortex stimulation at high spatial resolution using standard 1.5 T imager.

This paper reports the effects of motor cortex stimulation of normal volunteers using conventional MR imaging techniques on standard 1.5 T clinical scanner. Improvement in signal-to-noise (S/N) ratio has been achieved by using a commercially available eye/ear surface coil with a loop of 8.5 cm in diameter. Magnet shimming with all first order coils was performed to the volunteer's head resulting in a magnetic field homogeneity of about 0.1-0.2 ppm. The imaging technique used was an optimized conventional 2D and 3D, first order flow rephased, gradient-echo sequence (FLASH) with fat-suppression and reduced bandwidth (16-28 Hz/pixel) and TR = 80-120 ms, TE = 60 ms, flip angle = 40 degrees, matrix = 128 x 128, FOV = 150-250 mm, slice-thickness = 2-5 mm, NEX = 1, and a total single scan time for one image of about 12-16 s. In the 3D FLASH measurements, a slab of 32 mm thickness with 16 partitions was evaluated. The motor cortex stimulation was achieved by touching each finger to thumb in a sequential, self-paced, and repetitive manner. During stimulation, an increase in signal of order 10-20% was detected in the motor and sensory cortex due to reduced partial volume effects and optimized S/N for the measurements at small voxel size. 3D FLASH imaging at high spatial resolution shows good anatomical correlation of signal increase with gray matter of the motor and sensory cortex. The reported data demonstrate the technical feasibility of functional 2D and 3D MR imaging at high spatial resolution using optimized conventional sequences and equipment.