脾脏窦岸细胞血管瘤的影像学表现

目的探讨脾脏窦岸细胞血管瘤(LCA)的影像学特点,提高CT及MRI诊断脾脏窦岸细胞血管瘤的准确率。方法回顾性分析嘉兴市第一医院及嘉兴市中医院经手术病理证实的12例脾脏窦岸细胞血管瘤的影像学表现。其中4例行CT、MRI平扫及增强扫描,6例行CT平扫及增强检查,2例行MRI平扫及增强检查,分析病灶形态、大小、密度、信号及强化方式,总结其CT及MRI影像学表现特点。结果 12例患者,10例表现为脾肿大,其中4例表现为单发病灶,8例表现为多发病灶。病灶呈类圆形,病灶最大直径7.1cm,最小直径0.4cm,平均直径2.4cm;CT平扫8例病灶呈相对于脾脏稍低密度改变,4例病灶呈等密度而显示不清;增强扫描动脉期,部分病灶呈边缘"花边样"强化,病灶中央呈渐进性强化;3例多发病灶相对于脾脏稍低密度改变,增强呈较均匀的明显强化。MRI平扫均表现为T1WI稍低、T2WI稍高信号,DWI为高信号改变;MRI增强扫描呈"边缘强化,逐渐填充"的强化特点;部分病灶小于1.0cm,动脉期由于脾脏的"花斑样强化"特点,因而病灶显示欠清,平衡期因脾脏均匀强化,而逐渐凸显病灶。结论脾脏窦岸细胞血管瘤在CT及MRI上具有一定特征性的表现,把握这些征象有利于提高诊断的准确率。     

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.     

肝紫癜影像学表现1例

本文报道1例肝紫癜影像表现。患者女,29岁,CT平扫示肝S6见类圆形稍低密度灶,增强扫描呈持续性强化,MRI平扫示病灶T 1WI呈等-稍低信号,T 2WI呈稍高信号,扩散加权成像呈稍高信号,表观扩散系数图呈等信号,钆塞酸二钠增强扫描示病灶呈持续性延迟强化,肝胆期呈不均匀稍低摄取,内见散在小点片状...     

脾脏错构瘤的CT和MRI表现

目的:探讨脾脏错构瘤(SH)的CT和MRI表现.方法:回顾性分析6例病理确诊的SH患者的CT和MRI影像学表现.结果:6例SH中5例为单发,1例为多发.病灶在CT平扫呈等或稍低密度,在T1WI上呈等或稍低信号,在T2WI上呈不均匀低信号(4例)或高信号(2例),其中2例病灶中心出现局灶异常信号.动态增强扫描4例病灶表现为早期弥漫不均匀轻度强化并随时间推移呈渐进性延迟性强化,2例表现为早期均匀较明显强化,2例病灶中心的局灶异常信号呈部分延迟强化.结论:SH的CT和MRI表现具有一定特征性,影像学检查特别是MRI是诊断SH的重要方法.     

肝脏上皮样血管内皮瘤的CT和MRI表现

目的 总结肝脏上皮样血管内皮瘤(HEHE)的CT和MRI表现.方法 搜集经手术或穿刺活检后病理证实的HEHE 11例,所有的病例均行CT检查,其中5例行CT平扫及双期增强扫描(动脉期+门静脉期),其他6例行CT平扫及三期增强扫描(动脉期+门静脉期+延迟期).11例中有5例加做MRI平扫及动态增强扫描.回顾性分析病变的生长方式、分布特点、密度(信号)特点、强化方式及邻近组织情况.结果 11例均表现为肝内多发病灶,大部分病灶位于肝包膜下,根据生长方式分为三型:结节型(5例),匍匐生长型(1例)和混合型(5例).CT平扫,病灶均呈低密度,直径＞2 cm的病灶内见类圆形更低密度.MRI平扫:病灶呈T1WI低信号、T2WI高信号,直径＞2 cm的病灶信号不均匀(T1WI内见更低信号,T2WI内见更高信号).其他影像学征象包括“棒棒糖征”(6例)、包膜退缩征(6例).增强扫描:病灶直径＜1 cm的表现为轻度较均匀强化;病灶直径为1～2 cm主要表现为轻度较均匀强化;病灶直径＞2 cm的多为不均匀渐进性强化.结论 HEHE的CT和MRI表现具有一定的特征性,其强化方式与病灶的大小相关.     

脾脏窦岸细胞血管瘤CT和MRI表现与病理对照

目的探讨脾脏窦岸细胞血管瘤(LCA)CT和MRI表现和病理学特征。方法搜集9例经手术病理证实为脾脏窦岸细胞血管瘤患者的临床及其影像学资料,回顾性分析其影像学及病理学特征。结果 9例均行CT平扫及动态增强扫描,其中3例行上腹部MRI平扫及动态增强扫描。9例脾脏体积不同程度增大,2例为单发病灶,病灶较大,边界清楚;其余7例为多发病灶,为多发类圆形小结节状,边界欠清。病灶CT平扫呈现低密度,MRI T1WI呈略低或等信号,T2WI上呈高信号,结节病灶内见散在细小T2低信号影,呈现"雀斑"样。DWI病灶呈现高信号。增强后病灶在CT和MRI上均呈现缓慢向心性强化。组织学上病灶由迷路样互相吻合的血管性腔隙构成,胞质内可见含铁血黄素颗粒。免疫组织化学染色提示肿瘤呈现血管内皮细胞和组织细胞抗原双重表达。结论脾脏窦岸细胞血管瘤影像学能够较准确反映其病理学特点,其影像学表现有一定的特异性。     

胰腺结核的CT及MRI诊断

目的 :探讨胰腺结核的CT及MRI表现,提高对胰腺结核的诊断水平。方法 :回顾性分析经病理证实及临床抗结核治疗病灶缩小确诊的胰腺结核患者6例,均行CT平扫及增强扫描,其中4例同时行MRI平扫及增强扫描。结果:CT检查发现胰头部结核性病变6例,平扫呈等或略低密度肿块,增强扫描后病灶呈轻度及中度不均匀性强化或呈环形强化;4例行MRI检查T1WI病灶呈等或略低信号,T2WI病灶呈等或略高信号,内见片状高信号,增强扫描后呈轻度强化2例,环状强化2例。结论:胰腺结核的CT及MRI表现为胰头部局灶性实质性或囊实性病灶,增强扫描后呈轻中度强化或蜂窝状环形强化,伴有胰周淋巴结或腹腔淋巴结肿大环状强化,可合并脾脏等腹腔结核灶,影像学表现有一定特异性。     

钙化上皮瘤的影像表现及病理基础

【摘要】目的：分析钙化上皮瘤的CT及MRI表现,并探讨其病理基础。方法：回顾性分析17例经手术病理证实的钙化上皮瘤患者影像学资料并复习相关文献,其中8例行CT平扫及增强扫描,6例行MR平扫及增强检查,2例仅行CT平扫,1例先行X线片,后行MR平扫加增强检查。结果：10例CT共13个病灶。8个病灶见钙化,其中5个病灶完全钙化。2个病灶见坏死。10个病灶边界清清楚,3个瘤周见絮状稍高密度影。8例CT增强扫描共11个病灶,其中3个轻度强化,5个不均匀中度强化,3个病灶完全钙化无强化。6例MR均为单发,2例T1WI呈等信号,T2WI呈外周高中央低信号,DWI呈环状高信号,增强呈“环靶征”。2例T1WI呈等或稍高信号,T2WI呈高信号,内见微囊状更高信号,灶周可见斑片状高信号,增强不均匀强化。2例T1WI呈稍低信号,T2WI均呈稍高信号,增强不均匀强化。1例X线片呈高密度,T1WI呈低信号,T1WI压脂呈不均匀稍高信号,T2WI压脂呈高低混杂信号,增强扫描不均匀强化,以中央强化较为明显。结论：钙化上皮瘤的影像表现有一定特征,当病灶位于皮下,边界清楚,CT见广泛泥沙样或致密的局灶性钙化,MR上见微囊状改变,增强扫描轻至中度强化,尤其呈“环靶征”表现时,应考虑到PM的诊断。     

头颈部血管瘤及血管畸形的CT、MRI诊断

目的:分析头颈部血管瘤及血管畸形的CT、MRI表现,探讨其诊断及鉴别诊断价值。方法:搜集经手术病理或DSA证实,临床及影像资料完整的47例头颈部血管瘤或血管畸形病例的资料,对其进行回顾性分析。CT检查33例,MRI检查14例。结果:海绵状血管瘤21例,T1WI呈均匀等或低信号,T2WI呈高信号,增强扫描呈中等不均匀强化并可见纡曲血管强化;CT平扫呈不均匀等密度、囊状低密度,3例可见圆点状静脉石,增强扫描轻至中等度强化,其中6例见线条状粗大纡曲血管影。蔓状血管瘤23例,病变弥漫,无明显边界。T1WI呈等信号,T2WI呈不均匀高信号,其内见粗大的流空血管影及低信号静脉石,增强扫描明显不均匀强化;CT平扫等密度,见高密度圆点状静脉石,增强明显强化,可见蚯蚓状粗大血管团。淋巴管瘤3例,边界清楚,平扫为低密度,增强扫描无明显强化。结论:CT及MRI可较好显示头颈部血管畸形,蔓状血管瘤为动静脉畸形或高流速血管畸形,影像见粗大纡曲的血管影。低流速的静脉畸形、淋巴管畸形须与头颈部其它囊性病变鉴别。     

肝脏局灶性结节增生的CT及MRI表现

目的:探讨肝局灶性结节增生(FNH)的螺旋CT及高场强MRI的影像学表现,提高FNH诊断准确率.方法:回顾性分析60例经手术病理证实的66个FNH.螺旋CT检查32例,MRI检查30例,其中2例同时做了CT和MRI.结果:CT发现33个病灶,MRI发现35个病灶,其中平扫中CT31个为均匀的低或稍低密度,2个为等密度,T1WI30个为低或稍低信号,5个为等信号,T2WI均呈高或稍高信号.病灶中心见点状,星状,裂隙状更低密度/信号:CT11个,T1WI16个,T2WI19个为更高信号.动脉期所有病灶均明显强化,病灶中心更低密度/信号区均未强化,病灶周围有增粗,扭曲血管影:CT7个,MRI10个.门脉期呈高或稍高密度/信号:CT21个,MRI33个.呈等密度/信号:CT10个,MRI2个.呈稍低密度:CT2个.病灶中心更低密度/信号强化:CT1个,MRI6个.延迟期呈高或稍高密度/信号:CT4个,MRI30个.呈等密度/信号:CT24个,MRI5个.呈稍低密度:CT5个.病灶中心更低密度/信号强化:CT10个,MRI15个.结论:平扫和动态增强螺旋CT及高场强MRI能较全面显示FNH的病理特征和血供特点,提高了和其它肝脏肿瘤的鉴别诊断能力.     

Stress MR imaging for evaluation of popliteal artery entrapment

The popliteal artery entrapment (PAE) syndrome has been recognized as a cause of arterial occlusion in young people. It is the result of an anomaly of the relationship between the popliteal artery and the gastrocnemius muscle. Eight young healthy volunteers (16 legs) and six patients (10 legs) with suspected PAE underwent magnetic resonance (MR) imaging. Gradient-echo images were obtained in axial planes with the leg at rest and during active plantar flexion against resistance. Imaging at rest allowed identification of PAE signs in only one leg, which had an anomalous medial course of the popliteal artery. In the other cases, only the stress technique was able to show signal loss in the popliteal artery due to muscular compression (two legs) or the presence of accessory muscle slip around the vessel (two legs), as confirmed at surgery. MR imaging is therefore a useful technique for the diagnosis of PAE because of its capability of combining information obtainable with other modalities.     

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse muscu-loskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1 -weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1weighted, gadopentetate dimeglu-mine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibro-myalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.     

Controversies in cervical spine imaging in trauma patients

No area of emergency radiology has generated as much discussion in recent years as the subject of cervical spine imaging for trauma patients. This review will be in three parts. The first will examine the indications for cervical imaging and will focus on those factors that make patients at high risk or low risk for cervical injury. The second part will discuss the merits of radiography and computed tomography as the main screening diagnostic examination. In addition to the roles of each modality in the evaluation process, such factors as efficacy of diagnosis, time (duration) of study, and cost will be discussed. Finally, the third part will explore the methods currently employed to clear the cervical spine in comatose patients.Presented at the Annual Meeting of the American Society of Emergency Radiology, Las Vegas, Nevada, 22–25 October, 2003     

Uterine contractions: Possible diagnostic pitfall at MR imaging

A total of 206 nongravid patients with various gynecologic problems underwent pelvic magnetic resonance (MR) examinations that included both sagittal T2-weighted and contrast agent–enhanced T1-weighted images. MR images were retrospectively reviewed to identify changes in endometrial configuration on serial images obtained during the same MR examination. In 20 MR examinations (all in women of reproductive age), endometrial distortion due to myometrial bulging was noted on T2-weighted or contrast-enhanced T1-weighted images. It was absent on other MR images obtained at different times. Myometrial bulging exhibited low signal intensity in 18 examinations. The finding resembled adenomyosis or leiomyoma on T2-weighted or contrast-enhanced T1-weighted images. These results evidence the presence of transient myometrial bulging and transient low-intensity myometrium in the nongravid uterus. This phenomenon is thought to represent uterine contraction. Clinicians should be aware of the potential presence of transient low-signal-intensity myometrial bulging that could present diagnostic problems in the normal uterus.     

Brodie Abscess: MR imaging appearance in 10 patients

The magnetic resonance (MR) imaging features of Brodie abscess have not yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bone abscess had a characteristic “target” appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time inversion recovery) images, (b) an inner ring isointense to muscle on T1-weighted images and with high signal intensity on T2-weighted and STIR images, (c) an outer ring hypoin-tense on all images, and (d) a peripheral halo hypointense on T1-weighted images. In six of eight cases, a soft-tissue mass was found. The two vertebral abscesses had a less specific appearance, with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.     

Right-side aortic arch with aneurysm of aberrant left subclavian artery: MR imaging appearance.

Reports of aneurysms of the subclavian artery in both normal and anomalous aortic arches have been rare. The authors describe a patient with a right-side aortic arch and an aneurysm of the aberrant left subclavian artery, which, to the authors' knowledge, is a previously unreported association. At presentation, the aneurysm appeared as a calcified left superior mediastinal mass. Magnetic resonance imaging enabled preoperative diagnosis and guided surgical planning.     

MR angiography of congenital heart disease: Value of segmented two-dimensional inflow technique and maximum-intensity-projection display

Magnetic resonance (MR) angiography of the cardiovascular system was evaluated in 41 patients with congenital heart disease by using a two-dimensional (2D) inflow technique based on a magnetization-prepared gradient-echo pulse sequence with segmented k-space data acquisition and electrocardiographic gating at 0.5 T. Inversion and saturation prepulses were used to suppress stationary tissue and enhance intravascular signal. Presaturation slabs were applied where certain vascular structures had to be suppressed. Sequence parameters were optimized by evaluating signal intensity and contrast characteristics for various flip angles and inversion and saturation delay times. The heart and intrathoracic vasculature were encompassed with 40–50 overlapping sections. Both 2D angiograms and maximum-intensity-projection images were evaluated. Combining data sets acquired in the sagittal and transverse orientations provided the most satisfactory information about the pulmonary arteries. The highest signal-to-noise ratios were obtained with a flip angle of 65° and short prepulse delay times. Two-dimensional MR angiography can provide useful diagnostic information but requires a thorough understanding of in-plane and hemodynamically induced signal intensity changes.     

Adrenal tissue characterization with 0.5-T MR imaging: Value of T2*-weighted images

The authors investigated the value of magnetic resonance (MR) imaging at 0.5 T for distinguishing adrenal adenomas from adrenal metastases. The series included 23 adrenal adenomas (18 nonhyperfunctioning, five hyperfunctioning) and 23 adrenal metastases from various organs. Adrenal tumor–liver signal intensity ratios on T1-, T2-, and T2*-weighted images were calculated for adrenal tissue characterization. Adrenal adenomas were more precisely distinguished from adrenal metastases on T2*-weighted images (21 of 23, 91%) than on T2-weighted images (15 of 23, 65%). T1-weighted images were not useful for this distinction. In conclusion, T2*-weighted images were better than routine T2-weighted images for distinguishing adrenal adenomas from adrenal metastases. It can be postulated that the total signal intensity of adrenal adenomas, which contain some fat components, decreased on T2*-weighted images because of an out-of-phase effect.     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.