摘要：

While MR imaging in brain tumors is tending toward theevaluation of biological tissue characterization, there is a little reportregarding physical constitutional features, which is important foroperating surgeon.Magnetization transfer (MT) between water protonsandthe semi-solid or solid components of tissue protons hasprovided arelatively new feature in clinical MR imaging. Not only has thetechnique of MT applied to the evaluation of tissue morphology, but ithas also provided a semi-quantitative method of non invasive tissuecharacterization based on the physico-chemical properties ofmacromolecules and water. We previously examined the optimizationof clinical MT using bovine serum albumin (BSA) to understand theintermolecular interaction of protein (1) In the study reported here, weapplied the clinical MT sequence to evaluate the histological andconstitutional featuresof intracranial meningioma. Materials andMethods Histological and constitutional features of meningioma Sixteen meningiomas were examined. All of the tumors thatwere removed surgically, via inner decompression,had a diameter ofgreaterthan 2 cm. The relationship between the MT effect andhistological featuresof the tumors was evaluated. Still more, therelationship between the MT effect and the constitutional feature of thetumors, as observed on surgical resection was evaluated. Theconstitutional feature of the tumors included two classifications: softtumors those were removed easily using a standardsuction tube orspecial instrument; Cavitron ultrasonic aspirator (SVS-205, AlokaLSD, Tokyo, Japan), setat less than 50% of full power (sot?tumorgroup), and sticky or hard tumors those were removed by a Cavitronultrasonic aspirator setat over 50% of full power (hard tumor group). Determination ofA4TR inpatienti A 1.5-tesla MR, Signa clinical imaging system, a unitequipped with software at the 5.3 level (GE Medical Systems,Milwaukee, USA), was used with a quadrature head coil. The MRimaging protocol was as follows: spoiled gradient recalled acquisition(SPGR) in a two-dimensional mode, TR 50 msec, TE 5 msec, flipangle 30 degree, section thickness 5mm with a 2 mm intersection gap.The matrix was 256 x 192, and the section thickness was 5 mm. TheMT single cycle sine pulse had a duration of 18 msec and utilizedwaveform areathat was 10 times greater than that of a 90 degree spin-echo pulse, using 1000 Hz offset frequency, previously optimized6.Images were acquired both with and without the MT pulse using thesameslice, receive attenuation and transmit attenuation parameters. Weevaluated the MT effect using MT ratio (MTR) (MTR = 1 - MS / MO,where MS is the intensity of the signal that was obtained with the MTpulse, and MO is the intensity of the signal that was obtained withoutthe MT pulse). The MT was performed in the patients of brain tumor,all of whom provided informed consent documents. All patients wereinitially imaged using a conventional MR imaging technique, Beforeinjection of gadopentetate dimeglumine, the sequencesboth with andwithout the 1000 lXz offset RF pulse were performed. The specificabsorption rates were well below the safety limits. The signal intensitymeasurementswere carried out at particular regions of interest (ROI),which comprised a circle with an area of46 mm2, or 52 pixels, Thesignal intensity was measuredin five homogeneously enhanced regionswithin the area of the tumor and averaged in order to correct forregional field inhomogeneties and the partial-volume effect, Thecalculated MTRs in each group were compared using an unpaired one-tailed Student's t-test, assuming a normal distribution within eachgroup, The level of statistical significance was setat p4I.05. Results The mean value and standard deviation for MTRs ofmeningioma, was 0.31 * 0.04 (s16). The MTR (0.31) ofmeningiomas was significantly lower than that of normal brain tissue(white matter; 0.48, gray matter, 0.40). The mean values and standarddeviations for MTRs of fibrous type and meningothelial type were 0.32+ 0.03 (n=8) and 0.29 * 0.04 (n=7), respectivity. The MTR of fibroustype was high

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