肝脏孤立性坏死结节的MR表现

目的探讨MRI对各型肝脏孤立性坏死结节（SNN）的诊断价值。方法分析经手术病理证实的SNN9例，并结合文献资料探讨其分型、各型的MR表现及其病理基础。结果（1）单纯凝固性坏死型（5例），MRI的T1WI及T2WI上分别表现为低信号或低-等信号，增强扫描病灶内部无强化，周围包膜呈轻．中度强化。病理显示为单纯凝固性坏死，外围有薄层纤维包膜。（2）伴液化性坏死型（1例），T1WI上表现为低信号，较大病灶内可见点片状更低信号；T2WI上病灶呈低-等信号，其内可见点片状高信号；增强后病灶内部无强化，周围包膜呈轻-中度强化。病理上以凝固性坏死为主，中心可见裂隙状液化性坏死，外围有薄层纤维包膜。（3）多结节融合型（3例），T1WI为低信号，其内可见低．等信号分隔；T2WI病灶以低信号为主，其内可见等或略高信号分隔；增强扫描病灶内部无强化，其内分隔及周围包膜呈轻-中度强化。病理呈多个坏死结节融合，病灶以凝固性坏死为主，部分较大结节内可见小片状液化性坏死，结节间可见纤维分隔及外围薄层纤维包膜。结论MRI能很好反映SNN的分型及各型的病理特征。     

肝脏孤立性坏死结节的MRI表现

目的 总结肝脏孤立性坏死结节(SNN)平扫和动态增强MRI特征性表现.方法 回顾性分析经手术病理证实的15例SNN的MRI征象,对病灶数目、形状、大小、部位、边界、平扫和增强后信号及强化方式进行评价.结果 病灶单发14例,另1例有2个病灶.平扫T1WI及T2WI各发现15和14个病灶,增强扫描发现16个病灶.14个病灶最大径≤3 cm.平扫T1WI病灶呈低信号5个,略低信号9个,1个呈等信号伴有周边低信号包膜及内部点状低信号.在T2WI病灶呈高信号5个,略高信号4个,略低信号3个,明显低信号2个,其中2个病灶内见点状或细线样极高信号.16例在增强扫描后各期均呈低信号,尤其在门静脉期及延迟期呈明显低信号,边界及形态显示清楚.12个病灶形状不规则,4个病灶呈圆形或卵圆形.增强后病灶内部均未见强化,3个病灶在门静脉期及延迟期可见细环状轻度强化的包膜.结论 SNN特征性MRI表现有助于与肝脏其他肿瘤鉴别.     

肝脏孤立性坏死结节的MRI表现

目的 探讨肝脏孤立性坏死结节(solitary necrotic nodule ,SNN)的MRI表现.方法 分析经手术病理证实的SNN 20例的MRI表现.结果 依据其在MRI的T1WI和T2WI信号高低及增强后的表现分为4类:(1) 4个病灶在T1WI和T2WI均表现为低信号,其中2个病灶在T2WI上其内可见点状高信号,增强后无强化;(2)7个病灶在T1WI低信号,T2WI稍高信号,增强后无强化;(3)4个病灶在T1WI低信号,T2WI呈稍高信号,增强后门脉及延迟期边缘强化;(4)5个病灶在T1WI低信号,T2WI呈稍高信号伴中央点状或片状更高信号,增强后边缘强化.结论 平扫加动态增强MRI能较好反映SNN的影像学特点,提高了SNN的诊断准确率.     

肝脏孤立性坏死结节的CT及MRI表现

目的:探讨肝脏孤立性坏死结节(SNN)的螺旋CT及高场强MRI表现,提高对SNN的诊断准确性。方法:回顾性分析30例(34个)经手术病理证实的SNN患者的影像学表现。其中10例行螺旋CT平扫和3期动态增强检查,20例行MRI平扫及增强检查。结果:CT发现11个病灶,MRI发现23个病灶。CT平扫示病灶均呈低或稍低密度,6例中央可见星芒状更低密度区,增强扫描动脉期病灶均无明显强化,延迟期4个病灶有边缘强化。MRT1WI示23个病灶均为低或稍低信号,10个病灶中心见点状、星状更低信号;T2WI示5个病灶呈稍低信号、18个为稍高信号;增强扫描动脉期所有病灶均未见明显强化,8个病灶门脉期及延迟期边缘强化。16个病灶中心更低密度/信号区均未见强化。结论:CT平扫和动态增强及MRI能较好地反映SNN的影像学特点,提高了对SNN的诊断准确性。.     

腹部促结缔组织增生性小圆细胞肿瘤的CT、MRI表现

目的 探讨腹部促结缔组织增生性小圆细胞肿瘤(desmoplastic small round cell tumor,DSRCT)的CT、MRI表现.资料与方法 回顾性分析经病理证实的7例DSRCT患者的临床及影像学资料,7例中单发2例,多发5例;病灶直径＞10 cm者5例.7例均行CT检查,2例在1周内行MRI.结果 腹、盆腔内可见分叶状或结节状低密度肿块,其内有小片状坏死,5例可见斑点状钙化;增强扫描2例轻度强化,5例中度强化;病灶与浆膜面关系密切,对周围组织及血管呈推移、包绕、侵犯倾向,但无明显起源关系,5例病灶内可见分隔状强化血管影.2例伴腔积液;2例肝转移、骨转移;3例淋巴结转移.MR T1WI上呈等低信号,T2WI呈稍高信号,其内可见更高信号的囊变坏死区.结论 CT和MRI表现为腹、盆腔内巨大结节状或分叶状肿块,特别是位于膀胱后方或子宫直肠区域,与周围器官无明显起源关系,广泛腹膜、网膜种植,肿瘤呈不均匀低密度,内见斑点状钙化及小片状坏死,腹腔积液少见,增强扫描呈轻、中度强化,可考虑DSRCT的可能.     

肝胆管囊腺癌的MRI表现

目的:探讨肝胆管囊腺癌(HBCAC)的MRI表现,提高肝胆管囊腺癌的诊断准确性.方法:回顾性分析9例经病理证实的肝胆管囊腺癌的MRI表现,所有患者均行MR平均和三期动态增强扫描.结果:9例中单囊性病灶8例,多囊性病灶1例.T1WI上6例表现为囊状低信号影,囊内分隔和囊壁厚薄不均,可见壁结节或乳头状突起;3例囊壁光滑,囊内呈稍高信号影,可见结节状软组织信号影.T2WI上病灶以高信号为主,囊内分隔、壁结节及软组织呈低信号.增强扫描动脉期示囊内分隔、壁结节和软组织明显强化,门脉期及延迟期强化仍较明显.结论:平扫及动态增强MRI能较好反映肝胆管囊腺癌的影像学特点,对本病的诊断及鉴别诊断有重要价值.     

MRI对微波固化治疗肝癌疗效的评价

目的评价1.5TMRI平扫和动态增强对肝癌微波固化治疗后表现和疗效随访的价值。方法回顾性分析26例32个病灶肝癌微波固化治疗后MRI表现,并与AFP和DSA结果进行对照。结果微波固化治疗3天后的MRI平扫表现,T1WI呈相对高信号,T2WI呈相对低信号,病灶周围可见长T1,长T2水肿带。微波固化治疗1月后的MRI表现①单独行微波固化治疗的19个病灶以凝固性坏死为主,平扫T1WI呈相对等高信号,T2WI呈相对低信号或等信号,动态增强扫描无强化;②多种介入方法联合应用的5个病灶,特别是与TACE联合治疗的病灶,以凝固性坏死、液化性坏死合并存在,表现为局部T1WI呈相对低信号,T2WI呈相对高信号,但动态增强扫描无强化;③8个病灶不完全坏死:在T1WI上呈相对高信号的病灶周边有低信号结节或同时伴新月形低信号带,在T2WI上则表现为等低信号病灶周边出现相对高信号结节或新月形高信号带,在动态增强扫描时呈快进快出强化表现。结论 MRI平扫和动态增强评价微波固化的疗效可靠、准确,微波固化术后定期MRI随访具有重要意义。     

肝脏局灶性结节增生的典型与非典型MR表现及其病理基础

目的:研究肝脏局灶性结节增生(FNH)的典型与非典型MR表现及其病理基础,探讨MRI对各型的诊断价值。方法:分析经手术病理证实的FNH 28例(36个病灶)的典型与非典型MR表现,并与病理结果相对照。结果:①典型表现20例(28个病灶),大小在2.0~10.5cm,T1WI上呈等/稍低信号,T2WI上呈等/稍高信号,增强扫描动、门脉期病变呈显著增强,延迟扫描呈等/略高信号,中心瘢痕出现率占42.9%(12/28例),于T1WI上呈低信号,T2WI上呈高信号,增强扫描呈延迟强化。组织学上有特征性的中央纤维瘢痕,由纤维结缔组织和扭曲的血管组成,并向外放射状形成许多纤维间隔,纤维间隔旁围绕以无明显异形性的肝细胞形成硬化样结节;②非典型表现8例(8个病灶),大小在1.5~8.5cm,T1WI呈略高或低信号,T2WI呈不均匀高信号,增强扫描病灶强化不显著、不均匀,病灶内未见中心瘢痕或瘢痕不强化,出现假包膜等。镜下病变内毛细胆管扩张,其内纤维分隔较短、不连续,部分较大病灶内有出血、脂肪变及坏死,但无异型性肝细胞。结论:MRI能很好反映肝脏局灶性结节增生的典型与非典型表现的病理基础,具有高度的诊断特异性。     

肝脏孤立性坏死结节的MRI和CT诊断及鉴别诊断

【摘要】目的：探讨肝脏孤立性坏死结节（SNN）的MRI、CT表现及其鉴别诊断价值。方法：回顾性分析经手术病理证实的47例SNN的临床及影像学资料。38例行腹部MRI平扫及增强检查,7例行腹部CT平扫及增强检查,2例同时行MRI和CT检查。结果：病灶位于肝右叶39例（39/47,83.0%）,肝左叶8例（8/47,17.0%）;分布于肝实质边缘42例（42/47,89.4%）,肝脏深部5例（5/47,10.6%）;病灶最大径≤2.5cm者25例（25/47,53.2%）、＞2.5cm者22例（22/47,46.8%）;形态不规则29例（29/47,61.7%）,呈圆形或椭圆形18例（18/47,38.3%）。MRI示所有病灶于T1WI上呈低信号-等信号,32例病灶T2WI上呈等信号-稍高信号、8例呈稍低信号。CT平扫示所有病灶内部呈稍低-低密度影,1例病灶边缘可见环形钙化。三期增强扫描显示所有病灶内部无强化,周边有薄环状延迟强化,其中18例病灶内间隔有轻度强化。结论：SNN的MRI、CT表现具有一定特征性,有助于该病的诊断。     

原发性透明细胞型肝癌的CT和MRI诊断

目的 探讨原发性透明细胞型肝癌的影像表现,评价CT和MRI对该病的诊断价值.方法 回顾性分析19例经手术病理证实的原发性透明细胞型肝癌的CT和MRI表现.13例行CT平扫和动态增强扫描,8例行MR T1WI、T2WI和动态增强扫描.结果 CT平扫13例病灶均为低密度,其中9例病灶内部见不规则的更低密度影.增强后动脉期所有病灶均有强化表现,9例病灶不均匀强化,病灶中心有无强化的低密度区.门静脉期11例病灶呈相对低密度,2例呈等密度.3例可见环形强化的包膜.MR T1WI上5例病灶为低信号,3例为稍高信号.T2WI上5例病灶为混杂高信号,3例为等、低信号.MRI增强动脉期所有病灶均有显著强化.门静脉期和延迟期7例病灶为相对低信号,1例为等信号.2例病灶见环形强化的包膜.结论 CT和MRI可显示原发性透明细胞型肝癌的特征性表现,有助于提高该病的诊断准确性.     

肾嫌色细胞癌:动态增强CT及MR表现

目的:分析肾嫌色细胞癌的影像学表现及其血液动力学特征与病理的关系,提高诊断准确性.方法:经手术病理证实的肾嫌色细胞癌16例,术前经螺旋CT或多层螺旋CT平扫、皮髄交界期和实质期扫描,注射流率3 ml/s;3例经MRI SE T1WI、T2WI和扰相梯度回波动态增强成像.仔细复习CT和MRI扫描结果并与手术病理作回顾性对照分析.结果:16例嫌色细胞癌中肿瘤呈球形14例,椭圆形2例,边缘光整.所有肿瘤平扫软组织密度均匀,3例可见钙化,1例瘢痕伴钙化.肿瘤直径3.5～13.0cm,平均7.6cm.实质性肿瘤15例,1例实质期增强可见小囊变.肿瘤平扫CT值22.7～34.2 HU,平均27.1 HU;动态增强皮髓交界期CT值30.4～71.8 HU,平均43.3 HU;实质期CT值32.9～82.4 HU,平均51.7 HU.4例可见轮辐状强化.3例行MRI检查,MR T1WI为略低信号,T2WI为略高信号,1例可见中心轮辐状瘢痕,皮髄交界期轻中度强化,实质期强化相仿.结论:肾嫌色细胞癌多位于髓质,瘤体呈球形,坏死囊变很少见,瘤肾分界截然;皮髄交界期强化低于、等于或高于肾髓质,但明显低于肾皮质,实质期强化多低于或等于皮髄交界期,少数高于皮髄交界期;轮辐状强化或轮辐状中心瘢痕超过1/3.     

Brachial plexus: correlation of MR imaging with CT and pathologic findings

Thirty-two patients with symptoms referable to the brachial plexus were evaluated with magnetic resonance (MR) imaging. Sixteen patients had undergone concurrent computed tomography (CT). MR imaging demonstrated normal findings in 16, 12 neoplasms, three cases of trauma, and one case of possible neural edema. Of the 16 patients with normal findings on MR images, eight had CT scans that were also normal. In one patient, MR images showed that the "mass" seen on CT was actually a tortuous blood vessel. In six of the 12 cases of neoplasm in which CT scans were available, MR imaging revealed more extensive disease. In the other six cases of tumor, MR imaging provided sufficient clinical information to obviate the need for CT or any other imaging modality. MR imaging provided definitive diagnoses in the three cases of trauma without further imaging. In one patient with paresthesia, MR imaging showed high signal intensity of the nerves on T2-weighted images, which was compatible with neural edema. A concurrent CT scan was normal.     

Fluid-attenuated inversion recovery MR imaging and subarachnoid hemorrhage: not a panacea

BACKGROUND AND PURPOSE: Subarachnoid hemorrhage (SAH) constitutes an important neurologic emergency. Some authors have suggested that fluid-attenuated inversion recovery (FLAIR) MR imaging can detect SAH that may not be apparent on CT scans but may be revealed by lumbar puncture. We sought to determine how often FLAIR MR imaging findings are positive for SAH in cases with negative CT findings and positive lumbar puncture results. METHODS: The CT scans and FLAIR MR images of all patients with suspected SAH during a 3-year interval (2000-2002) were retrospectively reviewed by a blinded reader. Among these cases, we identified 12 with CT findings that were negative for SAH, lumbar puncture results that were positive for SAH, and FLAIR MR imaging findings that were available for review. Eleven of the 12 patients had undergone FLAIR MR imaging within 2 days of CT and lumbar puncture. The 12 patients with negative CT findings were comprised of six male and six female patients with an age range of 7 to 69 years. We evaluated the true and false negative and positive FLAIR MR imaging findings for SAH by using the lumbar puncture results as the gold standard. The FLAIR MR imaging findings of 12 additional patients without SAH (as revealed by lumbar puncture) were used as control data for a blinded reading. RESULTS: For all 12 control cases without SAH, the FLAIR MR imaging findings were interpreted correctly. Of the 12 cases that had positive lumbar puncture results but false-negative CT findings for SAH, FLAIR MR imaging findings were true-positive in only two cases and were false-negative in 10. One of the two true-positive cases had the highest concentration of RBC in the series (365 k/cc), and the other had the second highest value of RBC (65 k/cc). CONCLUSION: FLAIR MR imaging cannot replace lumbar puncture to detect the presence of SAH. FLAIR MR imaging findings are infrequently positive (16.7%) when CT findings are negative for SAH. This is likely because there is a minimum concentration of RBC/cc that must be exceeded for CSF to become hyperintense on FLAIR MR images.     

肝脏局灶性结节增生影像分析

目的 :分析肝脏局灶性结节增生 (FNH )的CT、MR及DSA表现 ,提高对本病的认识。方法 :6例经证实的FNH ,均行CT、MR及DSA检查。结果 :6例病灶CT平扫低密度者 4例 ,均匀或不均匀 ,2例为等密度。增强动脉期所有病灶均有明显强化 ,除中心瘢痕外病灶强化均匀一致 ,3例可见到中心或周边增粗、扭曲的动脉。门脉期和延迟期扫描 4例病灶为等密度 ,2例为略高密度。 3例伴有中心瘢痕 ,1例无强化 ,2例延迟强化。 2例行DSA检查 ,病灶内分布较均匀的新生血管团。MR检查 4例 ,T1 WI呈等信号或略低信号 ,T2 WI呈略高信号。 1例行Gd DTPA增强延迟期呈略高信号 ,中心瘢痕无明显强化。结论 :CT、MR及DSA检查可充分反映FNH的血供特点和病理特征 ,动态增强是诊断FNH最有效的影像学手段 ,在诊断和鉴别诊断中具有很大价值     

Evaluation of cystic renal masses: comparison of CT and MR imaging by using the Bosniak classification system

PURPOSE: To compare computed tomography (CT) and magnetic resonance (MR) imaging in the evaluation of cystic renal masses by using the Bosniak classification system. MATERIALS AND METHODS: Images of 69 renal masses in 59 patients (38 men, 21 women; mean age, 60.4 years; range, 30-86 years), who had undergone both CT and MR imaging examinations within 1 year (average, 60.5 days; range, 0-356 days), were retrospectively analyzed by two radiologists in consensus. For each lesion, images were compared for thickness of wall and septa, number of septa, and presence of enhancement. Each mass was categorized (Bosniak classification) first on CT images and then on MR images, and results were compared. Pathologic correlation was available in 25 lesions. RESULTS: On CT images, there were 15 category I, 16 category II, 10 category IIF, 19 category III, and nine category IV lesions. Findings on CT and MR images were similar in 56 (81%) lesions; in 13 (19%) lesions, there were differences. In eight (12%) lesions, MR imaging depicted more septa than did CT, which resulted in an upgrade of the classification at MR imaging in two cases. In seven (10%) lesions, MR imaging depicted increased wall and/or septa thickness compared with CT, resulting in a classification upgrade in six cases. Three lesions had both increased numbers of septa and thickening of the wall and/or septa. In two (3%) lesions, enhancement characteristics at CT and MR imaging were different. One of these lesions also had an increased number of septa. Overall, MR imaging results led to a cyst classification upgrade of seven lesions, from category II to IIF (n = 2), IIF to III (n = 3), or III to IV (n = 2). Pathologic correlation in 25 lesions revealed 20 malignant and five benign lesions. CONCLUSION: CT and MR imaging findings were similar in the majority of cystic renal masses. In some cases, however, MR images may depict additional septa, thickening of the wall and/or septa, or enhancement, which may lead to an upgraded Bosniak cyst classification and can affect case management.     

肾上腺脑白质营养不良的影像分析

目的：分析肾上腺脑白质营养不良的影像特征及诊断价值。 材料和方法：回顾性分析16例临床证实的肾上腺脑白质营养不良患者的CT和MR影像;MRI检查10例,4例增强成像,CT扫描12例,3例增强。结果：16例患者均有典型的双侧侧脑室枕角旁白质内大片对称性低密度或中长T1长T2信号病变,经胼胝体压部相连,呈蝶翼状分布;此外,病灶还见于额、顶、颞叶、内囊、小脑、脑干,视路和听路病灶对称。5例见低密度灶内细点状、簇状钙化灶。6例增强均见花边样强化,平扫等T1长T2信号灶见强化;1例连续观察见病变向前、向下、向周围发展,并沿传导束分布。结论：肾上腺脑白质营养不良的CT、MRI表现多有特征性,包括典型蝶翼状分布、花边样强化、对称性侵犯双侧视路和听路、沿传导束分布,有助于明确诊断。     

淋巴管瘤的影像学诊断与病理相关性分析

目的探讨淋巴管瘤的影像学表现与病理分型之间的关系，评价影像学诊断的价值。资料与方法搜集经手术病理证实的28例淋巴管瘤，其中行CT检查22例，MRI检查8例，3例经CT增强扫描，2例行MRI增强。回顾性分析其影像学表现。结果囊性淋巴管瘤19例，表现为单房或多房囊性薄壁肿块，密度均匀；海绵状淋巴管瘤5例，表现为蜂窝状结构，边缘不规则；血管淋巴管瘤3例．可有不均匀强化及“液-液”平面表现。单纯淋巴管瘤1例。结论影像学检查对淋巴管瘤的诊断具有重要价值，并能为临床治疗提供指导。     

前庭导水管扩大的CT和MRI的诊断(附14例报告)

目的本文回顾分析了14例前庭导水管扩大患者的CT、MRI资料,并对两种检查方法作了比较.方法14例患者作了高分辨的颞骨颅底横断位扫描,其中6例作了MRI多方位的扫描.具体测量相关数据.结果在CT图像上,在14位患者中12例双侧和2例单侧扩大的前庭导水管外口均大于1.5mm.MRI图像上,5例双侧,1例单侧内淋巴管和内淋巴囊均有扩大,骨外内淋巴囊扩大尤为明显.倾斜矢状位能清晰显示与前庭相连的扩大的内淋巴管.结论CT和MRI都能准确地判定前庭导水管扩大的存在,MRI更为直观、明显.     

不典型脑膜瘤的CT诊断

目的探讨不典型脑膜瘤的CT诊断。方法18例不典型脑膜瘤均行CT平扫,17例行CT增强扫描,均经手术病理证实。结果混杂密度的脑膜瘤11例,囊性脑膜瘤4例,完全强化性脑膜瘤3例。结论确定瘤体位于脑外是提高不典型脑膜瘤CT诊断准确性的关键,但也有极少数脑膜瘤表现不典型,在鉴别诊断时应引起注意。     

Marfan syndrome: evaluation with MR imaging versus CT

Twenty-five patients with Marfan syndrome underwent computed tomography (CT) and magnetic resonance (MR) imaging. MR images were interpreted in blinded fashion and then the results were compared with findings from CT scans. MR imaging was found to be equivalent to CT in the depiction of aortic, dural, and hip abnormalities in patients who had not undergone surgery. MR imaging was superior to CT in evaluation of postoperative patients because the artifact produced by Bjork-Shiley or St. Jude valves precludes adequate evaluation of the aortic root on CT scans, while producing only a small inferior field distortion, a "pseudo-ventricular septal defect," on MR images. The absence of radiation exposure is another significant advantage for the relatively young Marfan syndrome population, who require serial studies. MR imaging is the modality of choice for evaluation and follow-up of patients with Marfan syndrome and offers an appropriate means of screening their kindred.