Comparative Study of Dynamic Susceptibility Contrast Perfusion MR Images between Warthin's Tumor and Malignant Parotid Tumors / 고신대학교의과대학학술지

OBJECTIVES: To identify diagnostically meaningful differences between Warthin's tumor and malignant masses in the parotid gland by dynamic susceptibility contrast (DSC) MR imaging. METHODS: Eleven malignant parotid tumors and 9 Warthin's tumors were included. MR imaging was performed on all patients. Signal intensity time curves of tumors were obtained by DSC MR imaging and dynamic susceptibility contrast percentages (DSC%) were calculated. RESULTS: No significant difference was observed between malignant tumors and Warthin's tumors (P = 0.437), although DSC% values tended to be higher for Warthin's tumors. CONCLUSIONS: Warthin's tumor tended to have higher DSC% values than malignant parotid tumors, but this difference was not significantly different.

Hippocampus MRI Parallel Segmentation Using Three Dimensions Lattice Boltzmann Model with Prior Information / 中国医疗器械杂志

Getting volume change of hippocampus by segmenting on brain MRI is an important step in the diagnose of Alzheimer's disease and other brain disease. Three dimensional segmentation can make use of the correlation of image in gray and spatial position, so it has high accuracy. This paper proposes a novel three-dimensional lattice Boltzmann model combined with the surface evolution of deformable model and taking the prior information as an external force term to constrain the evolution of three dimensional surfaces. In order to solve the problem of high computational cost caused by 3D segmentation, the parallelization of the method is programmed on single GPU platform and dual GPU platform. Comparison experiments were set to test the accuracy of segmentation and computational efficiency between the novel LB method and another method by using 20 real AD patient's MRI from ADNI. In ensuring the accuracy of the segmentation, the time can be reduced to 12.76 s on single GPU platform, and 17.32 s on dual GPU platform, contrasting 132.43 s on CPU platform. It fully validates the characteristics of lattice Boltzmann method which can be highly parallelized.

Evaluation of Knee Joint after Double-Bundle ACL Reconstruction with Three-Dimensional Isotropic MRI

PURPOSE: To evaluate the knee joint after double-bundle anterior cruciate ligament (ACL) reconstruction with three-dimensional (3D) isotropic magnetic resonance (MR) image, and to directly compare the ACL graft findings on 3D MR with the clinical results. MATERIALS AND METHODS: From January 2009 to December 2014, we retrospectively reviewed MRIs of 39 patients who had reconstructed ACL with double bundle technique. The subjects were examined using 3D isotropic proton-density sequence and routine two-dimensional (2D) sequence on 3.0T scanner. The MR images were qualitatively evaluated for the intraarticular curvature, graft tear, bony impingement, intraosseous tunnel cyst, and synovitis of anteromedial and posterolateral bundles (AMB, PLB). In addition anterior tibial translation, PCL angle, PCL ratio were quantitatively measured. KT arthrometric values were reviewed for anterior tibial translation as positive or negative. The second look arthroscopy results including tear and laxity were reviewed. RESULTS: Significant correlations were found between an AMB tear on 3D-isotropic proton density MR images and arthroscopic proven AMB tear or laxity (P < 0.05). Also, a significant correlation was observed between increased PCL ratio on 3D isotropic MRI and the arthroscopic findings such as tear, laxities of grafts (P < 0.05). KT arthrometric results were found to be significantly correlated with AMB tears (P < 0.05) and tibial tunnel cysts (P < 0.05). CONCLUSION: An AMB tear on 3D-isotropic MRI was correlated with arthroscopic results qualitatively and quantitatively. 3D isotropic MRI findings can aid the evaluation of ACL grafts after double bundle reconstruction.

Myxopapillary Ependymoma of Filum Terminale Mimicking Nerve Sheath Tumor

Myxopapillary ependymoma is a distinctive subtype of glioma that occurs almost exclusively in the conus medullaris and filum terminale. Though magnetic resonance(MR) imaging is an effective diagnostic tool for the diagnosis of these tumors, there are no definite correlations between the preoperative radiological images and histopathologic findings. A 30-year-old man with low back pain and leg pain was presented. MR images demonstrated a well-defined intradural extramedullary mass at the L3-4 with strong homogenous enhancement. Based on radiological features, our tentative diagnosis was a nerve sheath tumor. However, the histopathologic report confirmed it as myxopapillary ependymoma.

MR Imaging of Uncommon Soft Tissue Tumors in the Foot: A Pictorial Essay

A large variety of masses occur in the foot. The foot is a comparatively rare site of soft tissue neoplasms. MRI has greatly improved the ability to detect and delineate soft tissue lesions and is now considered the gold-standard imaging technique in their investigation. Recently, we have encountered rare soft tissue tumors of the foot. The presented cases include benign masses such as granuloma annulare, angiomyoma, neural fibrolipoma, and giant cell tumor of tendon sheath, as well as malignant tumors such as melanoma, synovial sarcoma, rhabdomyosarcoma and extraskeletal myxoid chondrosarcoma. We wish to illustrate the MR findings of these uncommon soft tissue tumors to aid in their diagnosis.

Non-contiguous Multi-organ Involvement of an Inflammatory Myofibroblastic Tumor: A Case Report

An inflammatory myofibroblastic tumor (IMT) is relatively rare quasineoplastic lesion. An IMT usually presents as a single mass within a single organ or sometimes as multifocal lesions within a single anatomic region. An IMT involving noncontiguous multi-organs within different anatomic regions is extremely rare. We present a case of an aggressive IMT that involved the musculoskeletal system and multiple abdominal visceral organs.

Angiolipoma in the Cerebellopontine Angle: A Case Report

A 65-year-old female, who suffered with a longstanding headache, was admitted to our hospital. MR imaging and digital subtraction angiography (DSA) demonstrated a vascular fat-containing mass in the right cerebellopontine angle. The lesion was surgically removed and the diagnosis of angiolipoma was established. The symptoms subsided after the operation.

Microembolic Signals and Patterns of Diffusion-Weighted MRI Lesions in Acute Middle Cerebral Artery Ischemic Stroke

BACKGROUND: Microembolic signals (MES) have been implicated as an important mechanism of acute ischemic stroke in middle cerebral artery (MCA) stenosis. We conducted a prospective study to correlate MES and patterns of diffusion-weighted MR images (DWI). METHODS: A total of 211 consecutive patients with MCA territory ischemic symptoms within 24 hours of symptom onset were monitored for MES. Among them patients with acute ischemic lesion in MCA territory on DWI were included. MCA velocities on transcranial Doppler (TCD) examination, patterns and multiplicity of DWI lesions, and the degree of stenosis on MR angiography (MRA) were compared between MES positive and negative groups. RESULTS: MES were detected in 9 patients (17.3%) among 52 patients who fulfilled our inclusion criteria. The mean number of MES per 30 minutes was 9.11+/-5.94 (range, 1-19). Mean flow velocity of insonated ipsilateral MCA in MES positive group was higher than that of MES negative group (115.67+/-81.9 cm/s vs 58.07+/-23.5 cm/s, p= 0.032). The degree of MCA stenosis on MRA and the presence of MES had significant relationship (p=0.039), but there was no significant relationship between lesion multiplicity on DWI and the presence of MES (p=0.431). The frequency of symptom recurrence in the corresponding MCA territory during 90 days from the index stroke did not show statistical significance between two groups (p=0.681). CONCLUSIONS: Our results do not support the idea of direct causal relationship between MES and the mechanism of atherothrombotic MCA stroke. Further study is needed to identify whether the appearance of MES implicates a predictor for further ischemic events or a sign of recanalization.

Structural Brain Abnormalities in Juvenile Myoclonic Epilepsy Patients: Volumetry and Voxel-Based Morphometry

OBJECTIVE: We aimed to find structural brain abnormalities in juvenile myoclonic epilepsy (JME) patients. MATERIALS AND METHODS: The volumes of the cerebrum, hippocampus and frontal lobe and the area of the corpus callosum's subdivisions were all semi-automatically measured, and then optimized voxel-based morphometry (VBM) was performed in 19 JME patients and 19 age/gender matched normal controls. RESULTS: The rostrum and rostral body of the corpus callosum and the left hippocampus were significantly smaller than those of the normal controls, whereas the volume of the JME's left frontal lobe was significantly larger than that of the controls. The area of the rostral body had a significant positive correlation with the age of seizure onset (r = 0.56, p = 0.012), and the volume of the right frontal lobe had a significant negative correlation with the duration of disease (r = -0.51, p = 0.025). On the VBM, the gray matter concentration of the prefrontal lobe (bilateral gyri rectus, anterior orbital gyri, left anterior middle frontal gyrus and right anterior superior frontal gyrus) was decreased in the JME group (corrected p < 0.05). CONCLUSION: The JME patients showed complex structural abnormalities in the corpus callosum, frontal lobe and hippocampus, and also a decreased gray matter concentration of the prefrontal region, which all suggests there is an abnormal neural network in the JME brain.

Serial Changes of MR Images Throughout the Stages of Infection of Spondylodiscitis

OBJECTIVE: Spondylodiscitis has been diagnosed by clinical, radiological and laboratory methods. MR imaging is well known as an excellent diagnostic tool for spondylodiscitis. However, the changes in MR images throughout the treatment process has not been studied. Thus we have analyzed the serial changes of MR images throughout the stages of infection. METHODS: Ten patients were selected for retrospective reviewed who had been treated at our institute for infectious spondylodiscitis between 2000 and 2005. These patients had been followed-up at least six months and had taken more than a couple of series of MR scans. We classified the MR images into four groups according to the stages of treatment for the infection and compared them to the clinical and laboratory findings. RESULTS: MR image signals changed minimally or appeared to be normal in the early stages. The progression of spondylodiscitis was characterized by a low T1 WI signal and a high T2 WI signal in disc and vertebral body. The signal changes of the MR images were then propagated and the endplate was destructed. During the treatment, the destructed endplate became stabilized and the signal intensity of both T1 and T2 WI were fixed to low-or iso-intensity. CONCLUSION: We can determine the serial signal changes based on MR images according to the treatment of spondylodiscitis. We can therefore determine the status of the infection and the stage of treatment, as well as the diagnosis of spondylodiscitis using serial MR images.

MR Findings of Metaplastic Carcinoma of the Breast: Case Report

We report the dynamic magnetic resonance imaging findings (MRI) of a metaplastic carcinoma of the breast. A 44-year-old woman presented with a 2-month history of a mass in the right breast. The tumor showed a central irregular necrosis that was depicted upon low signal intensity on a T1-weighted image and high signal intensity on a T2-weighted image. The periphery of the tumor showed strong enhancement on a contrast enhanced T1-weighted image. The time-signal intensity curve revealed an early strong contrast enhancement and a delayed washout pattern.

Gd(DTPA)2--enhanced, and Quantitative MR Imaging in Articular Cartilage

PURPOSE: Early degeneration of articular cartilage is accompanied by a loss of glycosaminoglycan (GAG) and the consequent change of the integrity. The purpose of this study was to biochemically quantify the loss of GAG, and to evaluate the Gd(DTPA)2--enhanced, and T1, T2, rho relaxation map for detection of the early degeneration of cartilage. MATERIALS AND METHODS: A cartilage-bone block in size of 8mmx10 mm was acquired from the patella in each of three pigs. Quantitative analysis of GAG of cartilage was performed at spectrophotometry by use of dimethylmethylene blue. Each of cartilage blocks was cultured in one of three different media: two different culture media (0.2 mg/ml trypsin solution, 1mM Gd (DTPA)2- mixed trypsin solution) and the control media (phosphate buffered saline (PBS)). The cartilage blocks were cultured for 5 hrs, during which MR images of the blocks were obtained at one hour interval (0 hr, 1 hr, 2 hr, 3 hr, 4 hr, 5 hr). And then, additional culture was done for 24 hrs and 48 hrs. Both T1-weighted image (TR/TE, 450/22 ms), and mixed-echo sequence (TR/TE, 760/21-168ms; 8 echoes) were obtained at all times using field of view 50 mm, slice thickness 2 mm, and matrix 256x512. The MRI data were analyzed with pixel-by-pixel comparisons. The cultured cartilage-bone blocks were microscopically observed using hematoxylin & eosin, toluidine blue, alcian blue, and trichrome stains. RESULTS: At quantitation analysis, GAG concentration in the culture solutions was proportional to the culture durations. The T1-signal of the cartilage-bone block cultured in the Gd(DTPA)2- mixed solution was significantly higher (42% in average, p0.05). However the focal increase in T1 relaxation time at superficial and transitional layers of cartilage was seen in Gd(DTPA)2- mixed culture. Toluidine blue and alcian blue stains revealed multiple defects in whole thickness of the cartilage cultured in trypsin media. CONCLUSION: The quantitative analysis showed gradual loss of GAG proportional to the culture duration. Microimagings of cartilage with Gd(DTPA)2--enhancement, relaxation maps were available by pixel size of 97.9x195 micrometer. Loss of GAG over time better demonstrated with Gd(DTPA)2--enhanced images than with T1, T2, rho relaxation maps. Therefore Gd(DTPA)2--enhanced T1-weighted image is superior for detection of early degeneration of cartilage.

An Acoustic and Radiologic Study on Voice Change after Laser Assisted Uvulopalatoplasty / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Many people have been concerned about voice change after laser assisted uvulopalatoplasty (LAUP). A number of studies reported acoustic changes after uvulopalatopharyngoplasty (UPPP) and LAUP. However, there have not been any reports on the association between anatomic change and acoustic results after LAUP. The purpose of this study is to analyze changes in the voice and changes in the vocal tract after LAUP and to evaluate whether the anatomical changes of vocal tract have an effect on the voice change or not. SUBJECTS AND METHOD: By using CSL, we analyzed fourteen LAUP cases on the formant frequencies of six vowels (/a/, /i/, /u/, /=, /o/, /e/) and four nasal consonants (/hana/, /eomma/, /eoungga/, /chiken/). By using MR image, we analyzed changes in the vocal tract eight weeks after LAUP with preoperative findings in three cases. RESULTS: In acoustic analysis, the second formant frequencies of /u/ and /= phonation were significantly reduced postoperatively compared to those of preoperative status. In imaging study of /u/ and /=, the uvula and soft palate were contracted, so coupling was occurred between nasal cavity and oropharynx in /u/ and /= phonation and the tongue was shifted toward posterior pharyngeal wall to compensate coupling. CONCLUSION: LAUP reduced the second formant of /u/ and /=, which did not result in serious voice changes.

Effect of Steroid on Brain Tumors and Surround Edemas: Observa tion with Regional Cere b ral Blood Volume (rCBV) Maps of Perfusion MRI

PURPOSE: To observe the hemodynamic change in brain tumors and peritumoral edemas after steroid treat-ment, and then nvestigate the clinical usefulness of perfusion MRI. MATERIALS AND METHODS: We acquired conventional and perfusion MR images in 15 patients with various in-tracranial tumors (4 glioblastoma multiformes, 4 meningiomas, 3 metastatic tumors, 1 anaplastic ependymo-ma, 1 anaplastic astrocytoma, 1 hemangioblastoma, and 1 pilocytic astrocytoma). For perfusion MR imaging, a 1.5T unit employing the gradient-echo EPI technique was used, and further perfusion MR images were ob-tained 2-10 days after intravenous steroid therapy. After processing of the raw data, regional cerebral blood volume (rCBV) maps were reconstructed. The maps were visually evaluated by comparing relative perfusion in brain tumors and peritumoral edemas with that in contralateral white matter. Objective evaluations were performed by comparing the perfusion ratios of brain tumors and peritumoral edemas. RESULTS: Visual evaluations of rCBV maps, showed that in most brain tumors (67%, 10/15), perfusion was high before steroid treatment and showed in (80%, 12/15) decreased afferwards. Objective evaluation, showed that in all brain tumors, perfusion decreased. Visual evaluation of perfusion change in peritumoral edemas revealed change in only one case, but objective evaluation indicated that perfusion decreased signifi-cantly in all seven cases. CONCLUSIONS: rCBV maps acquired by perfusion MR imaging can provide hemodynamic information about brain tumors and peritumoral edemas. Such maps could prove helpful in the preoperative planning of brain tumor surgery and the monitoring of steroid effects during conservative treatment.

Effect of Steroid on Brain Tumors and Surround Edemas: Observa tion with Regional Cere b ral Blood Volume (rCBV) Maps of Perfusion MRI

PURPOSE: To observe the hemodynamic change in brain tumors and peritumoral edemas after steroid treat-ment, and then nvestigate the clinical usefulness of perfusion MRI. MATERIALS AND METHODS: We acquired conventional and perfusion MR images in 15 patients with various in-tracranial tumors (4 glioblastoma multiformes, 4 meningiomas, 3 metastatic tumors, 1 anaplastic ependymo-ma, 1 anaplastic astrocytoma, 1 hemangioblastoma, and 1 pilocytic astrocytoma). For perfusion MR imaging, a 1.5T unit employing the gradient-echo EPI technique was used, and further perfusion MR images were ob-tained 2-10 days after intravenous steroid therapy. After processing of the raw data, regional cerebral blood volume (rCBV) maps were reconstructed. The maps were visually evaluated by comparing relative perfusion in brain tumors and peritumoral edemas with that in contralateral white matter. Objective evaluations were performed by comparing the perfusion ratios of brain tumors and peritumoral edemas. RESULTS: Visual evaluations of rCBV maps, showed that in most brain tumors (67%, 10/15), perfusion was high before steroid treatment and showed in (80%, 12/15) decreased afferwards. Objective evaluation, showed that in all brain tumors, perfusion decreased. Visual evaluation of perfusion change in peritumoral edemas revealed change in only one case, but objective evaluation indicated that perfusion decreased signifi-cantly in all seven cases. CONCLUSIONS: rCBV maps acquired by perfusion MR imaging can provide hemodynamic information about brain tumors and peritumoral edemas. Such maps could prove helpful in the preoperative planning of brain tumor surgery and the monitoring of steroid effects during conservative treatment.

Determination of Language Dominance Using Functional MRI in Patients with Intractable Seizure: Comparison with Wada Test

PURPOSE: To investigate the efficiency or potency of functional MRI (fMRI) for the determination of language dominance by comparing the results of fMRI with those of the Wada test. MATERIALS AND METHODS: Among 34 patients with intractable seizure who underwent both fMRI and the Wada test, we analyzed the results of 30 (men:women=19:11; mean age=29.7 years). Using echoplanar imaging and the blood oxygen level dependent technique, fMRI was performed using a 1.5 T MR imager with a standard head coil. The language task consisted of two parts: reading words and generating words. For fMRI, a multi-event multi-task paradigm consisting of two sets of activation, rest, and alternative periods was used. Image processing involved the use of the Z test (Z threshold = 1.0 -1.2). To determine the lateralization index, we calculated the activation pixels within the whole frontal cortex., and to ascertain the discrepancy between the two tasks, the clustering grade of activation pixels was measured. After the injection of thiopental, language dominance was determined by means of a modified Wada test. The results of this and the findings of fMRI were compared with the results of Fisher 's exact test (p 0.05). CONCLUSION: For the determinaton of language dominance, fMRI showed good correlation with the Wada test. The word generation task was more efficient than the reading task. fMRI which is non-invasive and repeatable, is therefore more efficient and useful than the invasive Wada test.

The Usefulness of CT and MR Virtual Colonoscopy in the Evaluation of Experimental Polyp Models

PURPOSE: The purpose of this study was to evaluate the diagnostic accuracy of CT and MR virtual colonoscopy using an experimental model of colonic polyposis. MATERIALS AND METHODS: Eleven pig colons ranging from 15 to 20cm in length were cleansed and a total of 99 variable sized polyps ranging from 3 to 15mm in diameter were created. The polyps were divided into three groups according to size: <5mm(n=23), 5-9mm(n=44), and ?10mm(n=32) in diameter. Each specimen was scanned using spiral CT and MRI. Each CT and MR virtual colonoscopy was independently evaluated by two radiologists blinded to the location, size and numbers of polyps, but aware that polyps were present. Interobserver agreement regarding the detection rate of the polyps during the two types of virtual colonoscopy was measured and the diagnostic accuracy of CT and MR virtual colonoscopy was compared. Results: In both CT and MR virtual colonoscopy, the detection rates determined by the two radiologists coincided in all three groups(p<0.05). The detection rates of polyps less than 5mm, between 5 and 9mm, and 10mm or larger in diameter were 74%(17/23), 89%(39/44), and 100%(32/32), respectively, in CT colonoscopy, and 61%(14/23), 89%(39/44), and 100%(32/32), respectively in MR colonoscopy. In polyps 5mm or larger, the results of the two types of virtual colonscopy coincided but in those less than 5mm in diameter, the results of MR virtual colonoscopy were slightly inferior to those of CT colonoscopy. Conclusion: Both CT and MR virtual colonoscopy provide high detection rates of colonic polyps 5mm or larger in diameter and these techniques can therefore be used to diagnose colonic mass lesions.

The Usefulness of CT and MR Virtual Colonoscopy in the Evaluation of Experimental Polyp Models

PURPOSE: The purpose of this study was to evaluate the diagnostic accuracy of CT and MR virtual colonoscopy using an experimental model of colonic polyposis. MATERIALS AND METHODS: Eleven pig colons ranging from 15 to 20cm in length were cleansed and a total of 99 variable sized polyps ranging from 3 to 15mm in diameter were created. The polyps were divided into three groups according to size: <5mm(n=23), 5-9mm(n=44), and ?10mm(n=32) in diameter. Each specimen was scanned using spiral CT and MRI. Each CT and MR virtual colonoscopy was independently evaluated by two radiologists blinded to the location, size and numbers of polyps, but aware that polyps were present. Interobserver agreement regarding the detection rate of the polyps during the two types of virtual colonoscopy was measured and the diagnostic accuracy of CT and MR virtual colonoscopy was compared. Results: In both CT and MR virtual colonoscopy, the detection rates determined by the two radiologists coincided in all three groups(p<0.05). The detection rates of polyps less than 5mm, between 5 and 9mm, and 10mm or larger in diameter were 74%(17/23), 89%(39/44), and 100%(32/32), respectively, in CT colonoscopy, and 61%(14/23), 89%(39/44), and 100%(32/32), respectively in MR colonoscopy. In polyps 5mm or larger, the results of the two types of virtual colonscopy coincided but in those less than 5mm in diameter, the results of MR virtual colonoscopy were slightly inferior to those of CT colonoscopy. Conclusion: Both CT and MR virtual colonoscopy provide high detection rates of colonic polyps 5mm or larger in diameter and these techniques can therefore be used to diagnose colonic mass lesions.

Osteosarcoma: Correlation of T1 Map and Histology Map

PURPOSE: To determine whether T1 mapping shows regional differences between viable and necrotic regions of osteosarcomas after anticancer chemotherapy and to assess whether this mapping is able to express the characteristics of various intramural tissue components. MATERIALS AND METHODS: Eleven of 20 osteosarcomas were included in this study, while the remaining nine were excluded because the tumor site was inappropriate for comparison of T1 map and tumor macrosection. All patients underwent MR imaging for the purpose of T1 mapping, followed by pre-operative chemotherapy and subsequentl limb-salvage surgery. Spin echo pulse sequencing was used with varying TR (100, 200, 400, 800, 1600, and 2400 msec) and a constant TE of 20 msec. Using a C-language software program, T1 relaxation time was calculated on a pixel-by-pixel basis and then a T1 map was generated by using a post-processing program, NIH Image. We attempted correlation of the T1 map and histologic findings, particularly in regions of interest(ROI) if certain areas were different from other regions on either the T1 or histologic map. Value was expressed as an average of the ratio of T1 of ROI and T1 of fat tissue, and this was used as an internal reference for normalization of the measurement. RESULTS: Tumor necrosis was 100%(Grade IV) in six specimens, and over 90 % (Grade III) in five. Viable tumor cells were found mostly in regions with chondroid matrix and seldom in regions with osteoid matrix. Regardless of cell viability, values ranged from 0.9 to 9.87(mean, 4.02) in tumor necrotic area with osteoid matrices, and from 3.04 to 3.9(mean, 3.55) in areas with chondroid matrices. Other regions with fibrous tissue proliferation, hemorrhage, and fatty necrosis showed values of 2.92-9.83(mean, 7.20), 2.65 -5.96(mean, 3.59), and 1.43 -3.11(mean, 2.68) respectively. The values of various tissues overlapped. No statistically significant difference was found between regions in which tumors were viable and those with tumor necrosis. CONCLUSION: Although we hypothesized that areas of necrotic tumor would show an increased water component(proton number) and would have a longer T1 value than viable tumor tissues, our results were otherwise. Necrotic osteosarcoma tissves showed a wide range of T1 values according to the prevailing tissue components.

Cerebral Blood Volume and Relative Perfusion Rate Mapping with Contrast Enhanced Gradient Echo Echo PlanarImaging

PURPOSE: To assess regional cerebral blood volume and perfusion rate by MR imaging. MATERIALS AND METHODS:Eight normal volunteers and one patient underwent MR imaging after bolus injection of a double dose ofgadoinium(0.2mMol/kg). Gradient-echo EPI pulse sequencing was used, with TR/TE 1500/40msec, flip angle 90o, matrixsize 256X128. One hundred sequential images at the same level were obtained. The time-signal intensity curve wasplotted and converted to a time-concentration ( R2) curve. Relative cerebral blood volume was determined, withintegration of time-concentration curve pixel by pixel. Perfusion rate was determined by calculating maximal slopeof the R2 curve and the time taken to attain this. RESULTS: On volume maps, clear differentiation of gray matter,white matter and major vessels was established. The mean gray and white matter ratio of blood volume was2.78+/-0.43. Slope and volume maps were similar, but in one patient perfusion was apparently greater on the ratemap than on the volume map. CONCLUSION: Cerebral blood volvme and slope map images reflect changes in cerebralhemodynamics. It is thought that these findings can be clinically applied to the determination of vascularity inbrain tumors and acute cerebral ischemia