海马亚区T2信号对轻度认知损害治疗前后的评价研究

目的 探讨海马亚区MRI T2信号强度对轻度认知损害(MCI)患者盐酸多奈哌齐治疗前后疗效评估的价值.方法 收集MCI患者40例并随机均分为2组(治疗组及对照组).治疗组采用盐酸多奈哌齐治疗,对照组采用安慰剂治疗,治疗期为3个月.所有受试者治疗前后均行快速自旋回波T2序列,并在工作站勾画海马各亚区,测量其MRI T2信号强度并标准化,同时分析治疗组治疗前后海马各亚区MRI T2信号强度与简易精神状态检查(MMSE)评分的相关性.结果 治疗前,与对照组比较,治疗组双侧海马各亚区MRI T2信号强度差异无统计学意义.治疗后,治疗组双侧海马头部MRI T2信号强度较对照组显著降低,差异有统计学意义(P<0.05),而双侧体尾部MRI T2信号强度在治疗后差异无统计学意义.治疗组MMSE评分与治疗前后双侧海马头部MRI T2信号强度均呈负相关(P<0.05).结论 双侧海马头部MRI T2信号强度可有效评估MCI治疗后效果,可作为MCI早期诊疗有价值的辅助指标.     

MRI评价非何杰金氏淋巴瘤治疗后残留性病灶

作者评价了MRI在非何杰金氏淋巴瘤(NHL)治疗后活动性与残留性病灶鉴别诊断的应用价值。 8例NHL临床缓解病人,7例组织学分类为高度恶性,1例为中度恶性。7例单用化疗、1例单用放疗。在疗程末行MRI检查。如果治疗前的肿块经联合化疗和/或放疗后早期有反应,而完成治疗后大小稳定者称为残留病灶。在MRI后本组病例平均随访7个月(1～11个月)。结果见到,8例患者共有11个残留性病灶,其中7个病灶位于淋巴结、3个位于脾、1个位于肾。3例巨大肿块(直径>10cm)T_2加权象显示信号强度高于T_1加权象,其信号强度与脂肪信号强度相似。在随访1～3月间均出现病变进展,2例外周淋巴结活检及1例剖腹探查肿瘤组织活检证实为活动性淋巴瘤。3例均在MRI后5个月内死于活动性病变。其余5     

眼部淋巴瘤CT和MRI诊断

目的:分析眼部恶性淋巴瘤的CT和MRI表现特点,探讨二者诊断淋巴瘤的价值。方法:13例眼部淋巴瘤,CT检查12例,MRI检查5例。结果:所有病例经病理证实,其中10例为单侧,3例为双侧,均累及隔前眶周组织,8例以眼眶的上象限为主,5例以下象限为主,境界不清。5例呈局限性块影;8例呈弥漫软组织影,沿肌锥外向眶内浸润生长,同时累及泪腺和邻近眼外肌,并沿肌锥外向眶内生长呈铸形样改变;3例大部分眼环被肿瘤组织环绕,呈光芒样改变,并累及球后。CT平扫肿瘤组织呈境界欠清的中等密度软组织块影,MRI呈较低或略高信号强度,增强扫描肿块均呈较明显的均匀强化。结论:眼部恶性淋巴瘤的CT和MRI表现具有一些特征,影像学检查对本病的诊断具有重要价值。     

MRI脂肪抑制技术在乳腺肿瘤诊断中的应用

目的 评价MRI脂肪抑制技术在乳腺肿瘤诊断中的应用价值.方法 对60例女性乳腺(包括40例恶性和20例良性病变)进行MRI检查,选用频率饱和法压脂或反转恢复成像,30例行压脂三维动态增强扫描,并绘制它们的时间-信号强度动态曲线.结果 MRI脂肪抑制的乳腺图像显示40例46个良性病灶,20例22个恶性病灶.增强扫描MRI 30例显示38个病灶,20个良性,18个恶性.18个恶性病灶对比强化程度较病灶平扫时信号明显增高.乳腺动态增强的时间-信号强度曲线分型流出型14例恶性、2例良性;平台型3例恶性、2例良性;单相型1例恶性、16例良性;两者差异有显著性意义(P《0.01).单相型提示良性,平台型提示可疑恶性,流出型提示恶性.结论 MRI脂肪抑制成像及动态增强扫描是诊断乳腺肿瘤的有效方法.     

颅内原发恶性淋巴瘤的MRI诊断

目的分析颅内原发恶性淋巴瘤的MRI影像学特征.材料和方法对25例经手术及组织病理证实的颅内恶性淋巴瘤的MRI表现进行回顾性分析.结果25例中单发病灶18例,多发病灶6例,单纯室管膜下及蛛网膜下腔弥漫性浸润1例.平扫检查25例在T1WI呈稍低或低信号,T2WI呈等信号或稍高信号.增强扫描20例中17例病灶呈明显团块状增强,2例病灶轻度增强,室管膜下及蛛网膜下腔弥漫性浸润3例(单纯室管膜下及蛛网膜下腔弥漫性浸润1例)呈线样及小结节样增强,增强程度较均一.结论颅内原发恶性淋巴瘤的MR信号强度及增强方式对诊断和鉴别诊断具有重要价值.     

MRI评价高强度聚焦超声治疗子宫肌瘤对骶骨的影响

目的:应用MRI成像观察并检测子宫肌瘤高强度聚焦超声(HIFU)治疗前后骶骨MRI信号,评价HIFU治疗子宫肌瘤对骶骨影响的价值.材料和方法:对50例子宫肌瘤患者HIFU治疗前后行MRI成像检查,观察骶骨MRI信号的变化并在T1WI、T2WI和增强扫描矢状面上测定其信号值.结果:HIFU治疗子宫肌瘤后部分患者骶骨出现异常信号,其MRI T2WI信号强度增高,TIWI信号强度降低.结论:MRI可有效评价HIFU治疗子宫肌瘤对骶骨的影响.     

小脑半球肿瘤的MRI诊断与鉴别诊断

目的:分析小脑半球肿瘤的MRI表现及鉴别诊断。方法:回顾性分析42例经手术及病理证实的小脑半球肿瘤的MRI表现。结果:星形细胞瘤15例,单发转移性肿瘤10例,血管母细胞瘤8例,髓母细胞瘤6例,恶性淋巴瘤2例,室管膜瘤1例。结论:MRI能清晰显示小脑半球肿瘤的部位、大小、形态、信号强度和边缘等特征,具有重要的诊断价值。     

3.0 T磁共振扩散加权成像及表观扩散系数在淋巴瘤诊断及随访中的应用价值

目的 观察恶性淋巴瘤的扩散加权成像(DWI)特征及表观扩散系数(ADC)值在治疗前后的变化,探讨 DWI及ADC值在淋巴瘤诊断和随访中的应用价值.资料与方法 恶性淋巴瘤初发患者15例,男8例,女7例,平均年龄48.7岁.其中10例化疗后进行复查;健康志愿者10名,男5名,女5名,平均年龄48.4岁.在3.0 T MRI上行常规MRI及DWI检查.在ADC图上分别测量恶性淋巴瘤患者及健康志愿者颈部淋巴结的ADC值.10例复查患者在初次检查相一致部位再次测量淋巴结的ADC值,并进行前后对比,同时与健康志愿者进行比较.采用PSS 11.0统计软件,对淋巴瘤患者及正常对照组淋巴结的ADC值进行独立样本的t检验.结果 DWI与常规T2WI脂肪抑制序列比较,DWI能更敏感、直观地显示淋巴结.15例恶性淋巴瘤患者平均ADC值(753.33±31.28)×10-3 mm2/s,化疗后复查,平均ADC值(1088.32±51.28)×10-3 mm2/s.化疗前后ADC值差异有统计学意义(t=5.79,P＜0.05).健康志愿者颈部淋巴结平均ADC值(1264.20±71.60)×10-3 mm2/s.15例淋巴瘤患者治疗前ADC值与健康志愿者差异有统计学意义(t=6.53,P＜0.05),治疗后ADC值与正常人差异无统计学意义(t=1.97,P＞0.05).结论 3.0 T磁共振DWI及ADC值测量为淋巴瘤的诊断及疗效的观察提供了有价值的信息.     

乳腺病变的MRI诊断及鉴别诊断价值

目的 评价MRI扫描对乳腺病变的检出及良恶性病变鉴别诊断能力.方法 收集2007-02-2009-02间43例50枚(恶性＝21,良性＝29)乳腺病变患者,术前行MRI平扫及动态增强检查,检查序列T1WI、T2WI 、STIR(SPAIR)及3DTHRIVE动态增强.根据病灶形态及时间-信号强度曲线进行良恶性病变鉴别,并将影像检查结果与手术病理检查对照.结果 综合应用各MRI序列病变检出率分别98.00%;对恶性病变敏感性、特异性及准确性分别为80.95%、89.66%、86.00% .结论 MRI增强扫描及时间-信号强度曲线联合应用可提高乳腺病变诊断及鉴别诊断能力.     

脾肿瘤的MRI

脾肿瘤少见,主见于恶性淋巴瘤和白血病、造血系统肿瘤。作者对15例脾肿瘤作了MRI 检查,其中囊肿5例、脓肿2例、血管瘤1例、恶性淋巴瘤5例、转移癌2例;男9例,女6例;平均56岁;除囊肿和不明原因转移癌各1例经组织学证实外,余经US、CT 等检查和临床随访诊断。使用0.15T和0.5T 的MRI 装置,SE 序列,T_1加权(TR:400     

Residual mediastinal masses in Hodgkin disease: prediction of size with MR imaging

Eighteen patients with mediastinal involvement of Hodgkin disease were examined with magnetic resonance (MR) imaging before and during therapy to find out if size of residual masses could be predicted from the MR characteristics of the tumor at diagnosis. After the first treatment, a significant decrease in T2 values and signal intensity ratios of tumor to fat and tumor to muscle was found in all patients. There was no significant change in T1 values. The relative decrease in tumor size correlated well with signal intensity ratios and poorly with T2 values of the original tumor. No correlation with T1 values was found. The authors conclude that size of the residual mass can be predicted from the initial size of the tumor and the signal intensity ratios at diagnosis. Since the degree of low signal intensity in the tumor before treatment probably reflects the amount of fibrotic tissue, these results support the hypothesis that residual masses after treatment are remnants of the fibrotic stroma of the original tumor.     

Tumor recurrence versus fibrosis in the female pelvis: differentiation with MR imaging at 1.5 T

Twenty-two women with previous malignancies of the pelvis were examined with magnetic resonance (MR) imaging. In 21 of 22 patients, the MR imaging findings were confirmed with laparotomy on transvaginal biopsy. Twelve of the 22 patients had recurrent tumors; ten had a localized fibrotic mass, and two were found to have coexistent local fibrotic masses and distant recurrence. In 11 of the 12 patients with recurrence, MR imaging demonstrated the recurrent tumor as an area of increased signal intensity on long repetition time, long echo time spin-echo pulse sequences. Signal intensity of localized fibrosis varied with the time since initial treatment. Separate signal intensity measurements for T1- and T2-weighted images were obtained in regions of interest in recurrent tumors, early fibrosis (1-6 months after first treatment), and late fibrosis (more than 12 months). Ratios of signal intensity of muscle to that of fat were calculated, and a statistical analysis (Student t test) was performed. On heavily T2-weighted pulse sequences, the differences in signal intensity between late fibrosis and recurrent tumors were statistically significant (P less than .001). MR imaging is useful in identifying recurrent pelvic neoplasm and distinguishing it from posttreatment fibrosis.     

Urinary bladder neoplasms: evaluation with contrast-enhanced MR imaging

Forty-eight patients with urinary bladder neoplasms were examined with magnetic resonance imaging before and after intravenous administration of gadolinium diethylene-triaminepentaacetic acid (DTPA). Spin-echo sequences with short repetition and echo times were used in all patients; in 20 a gradient-echo technique was used to perform sequential imaging. In 31 patients ratios of tumor signal intensity to that of fat, muscle, and bone marrow were calculated before and after Gd-DTPA enhancement on T1-weighted spin-echo images. Increases in tumor signal intensity on T1-weighted spin-echo images were statistically significant after contrast enhancement (alpha = 1%, P less than .0001). The average rise in relative signal intensity after contrast enhancement was 120% for the tumor-fat ratio (tumor-marrow ratio, 105%; tumor-muscle ratio, 85%). Tumor signal intensity peaked within 120 seconds and remained on a plateau for up to 45 minutes. Necrotic tissue within the tumor, seen in three cases, was detectable only on contrast-enhanced images.     

Magnetic resonance relaxation times of normal tissue in the course of chemotherapy: a study in patients with bone sarcoma

To study the effect of chemotherapy on normal fat, skeletal muscle, and bone marrow, T1 and T2 relaxation times were measured in 15 patients with bone sarcoma before and after each cycle of preoperative chemotherapy. A section plane containing the tumor and if possible the nonaffected extremity was imaged with combined multiecho spin echo and inversion recovery pulse sequences. T1 and T2 relaxation times were calculated in the normal-appearing tissues. Although some variation was found in the values in the individual patient and between patients, no systematic changes of relaxation times of fat, muscle, or bone marrow occurred in the course of treatment. We conclude that the chemotherapy used in bone sarcoma has no effect on relaxation times of normal fat, muscle, and bone marrow, and that therefore these tissues may serve as a reference for the signal intensity of tumor.     

Theoretical considerations for optimizing intensity differences between primary musculoskeletal tumors and normal tissue with spin-echo magnetic resonance imaging

In the radiographic assessment of primary musculoskeletal tumors, it is important for therapy planning to accurately define the extent of a tumor. Using a double spin-echo pulse sequence, the T1 and T2 relaxation times and relative hydrogen densities of several neoplastic tissues and of several normal tissues in four patients were measured. Neoplasms measured included one fibrosarcoma, two osteosarcomas, and one giant cell tumor. Normal tissues measured included normal muscle, fat, and bone marrow. Using a mathematical model of the double spin-echo pulse sequence, the intensity difference between each tumor and each normal tissue for multiple values of TR and TE was calculated. These calculated intensity differences were then used to plot isodifference contour curves for each tissue pair. These plots enabled us to pick combinations of TR and TE that optimized the signal difference between tumor and normal tissue. When comparing tumor with predominantly fatty tissue such as marrow or subcutaneous fat, optimal signal difference in our imager occurred at a TR of 600 to 800 msec and a very short TE. When comparing tumor with muscle, optimal signal difference occurred with very long TR times, and TE times ranging from 30 to 90 msec. These preliminary results suggest that an optimal scanning protocol for primary musculoskeletal tumors should contain at least two different pulse sequences with widely separated TR values (500 and 2000 msec in our instrument), and short to intermediate values of TE (28 and 56 msec in our instrument). It is believed that analysis of isodifference contour plots is a useful method for optimizing intensity differences between any two tissue types.     

MRI对肺癌诊断的临床价值(附30例报告)

目的:分析肺癌的MRI信号特点,以探讨MRI在肺癌诊断中的价值。方法:回顾性分析30例肺癌MRI表现,以同层椎体为背景,按高、中、低三种等级将30例肺癌统计T2WI、T1WI信号强度变化。结果:中央型19例,在T2WI上呈高信号8例,等信号11例,信号均匀11例,信号不均匀8例;在T1WI上呈略高信号7例,等信号11例,低信号1例,信号均匀15例,不均匀4例。周围型11例,在T2WI上呈略高信号6例,等信号5例,信号均匀6例,信号不均匀5例;在T1WI上略高信号3例,等信号8例,信号均匀7例,信号不均匀4例。增强7例均显示明显强化,肿块与纵隔淋巴结呈一致性强化,肿块呈慢强化,阻塞性肺炎呈快速强化,坏死和纤维组织强化不明显。结论:肺癌的MRI平扫信号在T2WI上以稍高信号至等信号为主,在T1WI上以等信号至稍低信号为主,T2WI能区别实质性肿块与坏死、纤维组织和阻塞性病变,MRI扫描对肺癌制定治疗方案具有重要价值。     

12例软组织血管瘤MRI分析

目的;分析软组织血管瘤的ＭＲＩ表现及诊断价值。材料与方法：回顾性分析１２例软组织血管瘤,其中海绵状血管瘤８例,蔓状血管瘤４例,均经手术病理证实。结果：８例海绵状血管瘤均见肿瘤内部和／或边缘高信号灶,呈花边 或线太,类亿上脂肪信号,Ｔ２Ｗ小为不均匀高信号,内部有线条状或圆形低信号影。４例蔓状血管瘤于Ｔ１ＷＩ、Ｔ２ＷＩ上有煌流空信号,伴点状、条带状或花边状高信号,Ｔ２ＷＩ上大部分肿瘤信号高于肌肉信号而     

Granular cell tumor of the extremity: magnetic resonance imaging characteristics with pathologic correlation

Objective The purpose of this study is to delineate the magnetic resonance (MR) appearance of a granular cell tumor (GrCT) of the extremity and to correlate the imaging appearance with the microscopic findings.Design and patients A retrospective review of five patients with a histopathologic diagnosis of GrCT and pre-operative MR imaging of the neoplasm was done. The images were reviewed by two musculoskeletal radiologists in a consensus fashion. Lesion location, size, shape, margination, and signal intensity characteristics were assessed. MR findings were correlated with histopathological examination.Results The benign subtype of GrCT is usually isointense or brighter than muscle on T1-weighted sequences, round or oval in shape, superficial in location, and 4 cm or less in size. On T2-weighted sequences, benign lesions may demonstrate a high peripheral signal, as well as a central signal intensity that is isointense to muscle or suppressed fat. A significant stromal component in the tumor and, hypothetically, a ribbon-like arrangement of tumor cells may influence the signal intensity demonstrated on the T1 and T2-weighted sequences. The malignant subtype may demonstrate signal intensity characteristics and invasion of adjacent structures often seen with other aggressive neoplasms; sizes larger than 4 cm and association with major nerve trunks can be seen.Conclusion Benign GrCT has imaging characteristics which may distinguish this tumor from other soft tissue neoplasms, as well as the malignant type of this tumor.     

Hemangiomas of skeletal muscle: MR findings in five patients

Skeletal muscle hemangiomas are uncommon tumors of young adults. More than 90% are misdiagnosed preoperatively. Plain-film examinations, bone scans, CT studies, and angiography may not always be specific for this tumor. Seven MR examinations were performed in five young adult patients with pathologically proved skeletal muscle hemangiomas. All five hemangiomas showed high signal intensity on both T1- and T2-weighted images. The signal intensity in these tumors was less than that of subcutaneous fat on relatively T1-weighted images and greater than that of fat on relatively T2-weighted images. Four tumors had a serpiginous pattern. Four patients had focal muscle atrophy. Three patients had all three findings (high signal intensity on both T1- and T2-weighted images, serpiginous pattern, and associated focal muscle atrophy) while the other two patients had at least two of the three findings. These three patients did not undergo angiography or needle biopsies before surgery because the MR findings were highly suggestive of hemangioma. Our experience with this small series of patients suggests that skeletal muscle hemangiomas have a consistent appearance on MR. MR may be able to contribute significantly to the preoperative diagnosis of this tumor and may also supply valuable information about the extent of the lesion.     

Soft tissue perineurioma of the foot with 10q24 rearrangements: unique MRI features with histopathologic correlation

Perineurioma is an uncommon benign peripheral nerve sheath tumor with advanced perineurial differentiation. Two distinct subtypes are recognized: intraneural and soft tissue. We herein present a unique case of soft tissue perineurioma in the right foot of a 43-year-old man. Radiographs showed a non-specific soft tissue mass. On computed tomography scan, the mass was iso- to slightly hypodense relative to muscle. On T1- and T2-weighted images, the mass exhibited iso- to slightly low signal intensity relative to muscle with foci of high signal intensity. Slight contrast enhancement was noted on enhanced T1-weighted images with fat suppression. A marginal excision of the tumor was performed and histopathologic examination confirmed the diagnosis of soft tissue perineurioma. The clinicopathologic, radiologic, and cytogenetic findings are described, and the relevant literature is reviewed.