Objective To investigate the value of MR perfusion weighted imaging(PWI) to the evaluation of radiotherapeutic effect on gliomas. Methods MR PWI and conventional MRI examinations were performed respectively before radiotherapy and 3 and 6 months after radiotherapy in 25 patients with gliomas. The perfusion dada were deconvoluted to get color maps of cerebral blood volume (CBV) and cerebral blood flow (CBF). The relative values of regional CBV (rCBV) and regional CBF (rCBF) of the gliomas and cerebral tissues opposite to the gliomas were computed. Results In the gliomas and the cerebral tissues opposite to the gliomas to the gliomas, the rCBV were 6.32±2.14 and 2.58±1.21 respectively, and rCBF were 5.49±1.98 and 2.17±1.19 respectively before the radiotheraphy. The rCBV and rCBF of the gliomas increased before the radiotherapy in 25 patients compared to the cerebral tissues opposite to the gliomas (P0.01). Three and six months after the radiotherapy, rCBV and rCBF significantly decreased in 11 patients (P0.01), of whom, 5 had cerebral radionecrosis and 6 did not. The rCBV and rCBF of the gliomas increased to different extents after radiotherapy in 14 patients, of whom, 7 had the tumors with regional radionecrosis and 7 not. Conclusion MR PWI is a good method to evaluate the radiotherapeutic effect on the gliomas.

Objective To evaluate MR perfusing weighted imaging in differentiating of necrosis and recurrence of glioma after radiotherapy.Materials and Methods 32 patients with glioma(18 cases with recurrence and 14 cases with necrosis) having radiotherapy after surgery had MR perfusion imaging and MR conventional imaging.The color map of CBV and CBF were obtained from perfusion data.The maximal rCBV and rCBF ratios of each lesion and the normal side grey were calculated.Results PWI in 18 cases with recurrence of glioma exhibited increased rCBV and rCBF ratios.The maximal rCBV and rCBF ratios of recurrence of glioma were 6.23±2.23,5.21±1.55 respectively,each of the mormal side grey were 3.26±1.03(P0.01),2.41±1.15(P0.01) respectively;PWI in 14 cases with necrosis after radiotherapy exhibited decreased rCBV and rCBF ratios.The maximal rCBV and rCBF ratios of necrosis of radiotherapy were 1.90±0.53,1.21±0.32 respectively,each of the mormal side grey(matter) were 4.26±1.13(P0.05),3.36±1.24(P0.05);The maximal rCBV and rCBF ratios of recurrence of glioma were statistically different from those of necrosis after radiotherapy(P0.01).There was obvious correlation between the maximal rCBV and rCBF ratios(r=0.795 P0.05).Conclusion MR perfusion imaging is useful in differentiating of necrosis and recurrence of glioma after radiotherapy,especially using the maximal rCBF ratio with the maximal rCBV ratio.

Objective: To evaluate the value of diffusion weighted imaging (DWI) in the differential diagnosis of brain metastatic tumors and gliomas. Methods: ■urty-two patients with intracranial tumor were studied with convention MR imaging and DWI. On the basis of the pathological ■eport, the patients were divided into three groups (high-grade gliomas, low-grade gliomas, brain metastatic tumors). The app■rent diffusion coefficient (ADC) and relative ADC (rADC) of tumors, edema and contralateral normal brain were measured. Results: rADC of tumors were significantly different among low-grade glioma and metastatic tumors. rADC of edema were significantly different among high-grade glioma and metastatic tumors. Conclusion: DWI and the rADC of tumors and edema are valuable to differential diagnosis of brain metastatic tumors and gliomas in clinical application.

病例女,24岁.4年前出现间断头痛,以后枕部为重,未进行检查和治疗.11个月前头痛加重,并出现左耳听力下降,2个月前出现视物模糊.病人无恶心呕吐,四肢活动灵活,肌力正常,走路平稳,病理反射未引出.CT扫描:左侧小脑半球见一较大高低混杂密度肿物,边界欠清,其内可见线状更低密度影及小块高密度影.邻近颅骨厚薄不一,并可见骨质增生(图1).MRI平扫及增强扫描:左小脑半球见一类圆形以长T1、长T2信号为主的混杂信号肿物影.T1WI示低信号病灶内见线状及片状不规则形高信号影和毛发样更低信号影,病灶周边呈线状低信号,边界清楚.周围脑实质及四脑室受压变形,三脑室和侧脑室扩张,邻近硬脑膜局部缺损(图2,3).T2WI示病灶呈大片高信号(图4).增强扫描病灶周边呈轻度线样强化(图5).MRI诊断:左小脑畸胎类肿瘤.

Objective To evaluate the roles of magnetic resonance diffusion-weighted imaging (MRDWI) and apparent diffusion coefficient (ADC) value in differentiation of brain abscesses from necrotic or cystic gliomas. Methods The routine MRI and MRDWI examinations before the treatment were performed in 8 patients with cerebral abscess and 15 patients with necrotic or cystic gliomas. The signal intensities of the lesions on MRI and MRDWI were comparatively observed, and ADC values of the abscesses, necrotic or cystic parts of gliomas, surrounding edema area, normal white matters opposite to the lesions and cerebrospinal fluid(CSF) were separately measured. Results On MRDWI, all the brain abscesses manifested marked hyperintensity signals in 8 patients, whereas all the necrotic or cystic gliomas manifested hypointensity signals in 15 patients. The mean ADC values of the abscesses,necrotic or cystic parts of gliomas, and the surrounding edema area were significantly different from each other. Conclusions MR DWI and ADC can effectively reflect the different fluid properties of the abscesses and cystic or necrotic gliomas, and can be used to differentiate brain abscesses from necrotic or cystic gliomas.

病例1:患者女,33岁,右下肢小腿胀痛1月余.X线平片示右腓骨下段局部高密度影,似蜡滴状,与一侧骨皮质关系密切,骨皮质未增厚,骨髓腔明显狭窄近闭塞.X线诊断:蜡油骨病(图1).CT扫描示与骨皮质相连的高密度骨质增生,骨髓腔明显狭窄(图2).MR扫描示病变在T1及T2加权像上均呈低信号,周围软组织未见异常信号(图3).MRI诊断:骨质增生或钙化,考虑硬化性骨病.

病例资科 患者男,3 6岁.2年前无诱因出现右肩部肿物,质硬,于当地医院按"肩周炎"治疗,症状未缓解,肿物渐增大明显,半年前出现右肩肿物处疼痛,右上肢上举、外展不能.专科检查:脊柱呈生理弯曲,棘间、棘旁无压痛.右肩呈方肩畸形,可见一7.5 cm×7.5 cm肿物,质硬,皮肤温度及颜色正常,压痛阳性,活动度较差,三角肌萎缩.右上肢不能上举、外展,右上肢感觉未见异常,肌力正常.

弥散加权成像(diffusionweighted imaging,DWI)是在分子水平研究组织中自由水质子随意运动的功能磁共振成像技术,是目前在活体上进行水分子弥散测量与成像的唯一方法.DWI与传统MRI相比是一全新领域,这一技术第1次用在生物活体内无损伤地测量和描述弥散系数,研究分子微观运动,提供组织各部分的空间结构信息,了解正常和疾病状态下组织间的水交换[1].