侵袭性纤维瘤病的MRI特征

目的探讨侵袭性纤维瘤病的MR特征。方法对11例经手术病理证实的侵袭性纤维瘤病MRI征象进行回顾性分析。结果 11例侵性纤维瘤病表现为腹内或腹壁软组织肿块,肿块呈圆形、类圆形或不规则形、爪形。MRI检查,T2WI病灶均呈稍高信号;T1WI呈等信号6例,呈稍低信号3例,呈稍高信号2例;脂肪抑制T2像,病灶呈明显高信号,并能清晰显示肿瘤的边界及范围。其中4例病灶在各序列均见有条带状致密胶原纤维形成的低信号影。动态增强扫描动脉期及静脉期病灶轻中度不均匀强化,延迟期病灶明显强化并趋于均匀。其中4例病灶周边及内部残留有斑片状、条状无强化稍低密度区。结论侵袭性纤维瘤病的MRI表现具有一定特征性,MRI检查对该病有较高的诊断价值。     

颈肩部纤维组织源性肿瘤的MR和CT诊断

目的 分析颈肩部促结缔组织增生性成纤维细胞瘤及侵袭性纤维瘤病的MR、CT特征，重点讨论MRI表现的病理基础。方法 分析手术病理证实有MR或CT影像资料的颈肩部促结缔组织增生性成纤维细胞瘤4例及侵袭性纤维瘤病3例的影像表现，并与病理对照。结果 （1）4例促结缔组织增生性成纤维细胞瘤均位于颈部肌间隙中，类圆形，边界大部分清晰，1例在MRI上见包膜样改变。CT平扫为均匀低密度（2例）及等低密度夹杂改变（1例），增强后肿块强化不明显，密度改变与平扫时一致。肿瘤在T1WI上为均匀等信号（1例）或等低信号混杂改变（1例）；T2WI上2例信号相似于邻近的肌肉，不均匀伴有结节样的低信号或略高信号；增强扫描，病灶强化不明显，仍以等肌肉信号为主，伴有灶性低或略高信号。（2）3例侵袭性纤维瘤病均起源于肌肉本身，长梭形生长，长径与所侵犯的肌肉走向一致，边缘均不规则。CT平扫为等肌肉密度、边界不清晰的肿块（2例）；MRT1WI为均匀等信号的占位，边界不清晰（3例）；T2WI见夹杂条状或结节状低信号的稍高信号（2例）或均匀高信号（1例）；增强扫描肿块均明显强化，条状或结节状的低信号影及不规则的边界显示更加清晰，2例见边缘爪样浸润改变。结论 好发于不同年龄的促结缔组织增生性成纤维细胞瘤和侵袭性纤维瘤病都为纤维来源的软组织肿瘤，但影像改变完全不同，这与其不同的病理基础密切相关。MRI的诊断及鉴别诊断作用明显优于CT。     

腹部侵袭性纤维瘤病的CT及MRI特征

目的：探讨腹内侵袭性纤维瘤病的CT及MRI特征。方法：回顾性分析18例经手术病理证实的腹内侵袭性纤维瘤病CT及MRI表现。术前仅行CT检查9例,仅行MRI检查3例,同时行CT及MRI检查6例。结果：18例腹内侵袭性纤维瘤病表现为腹膜后或腹腔内软组织肿块。腹膜后肿块以浸润性生长呈不规则形、爪形多见;腹腔内肿块以膨胀性生长呈圆形、类圆形多见。CT检查15例中,平扫病灶呈稍低密度11例,等密度4例,病灶内未见坏死、钙化及脂肪密度,增强扫描动脉期病灶大部分呈不均匀轻度强化,静脉期病灶持续强化,延迟期强化最明显,其中9例病灶周边及内部残留有斑片状、条状无强化稍低密度区。MRI检查9例中,T2WI病灶均呈稍高信号;T1WI呈等信号5例,呈稍低信号4例;脂肪抑制T2WI序列,病灶呈明显高信号。其中6例病灶在各序列中均见有条带状致密胶原纤维形成的低信号影。动态增强扫描动脉期及静脉期病灶轻中度不均匀强化,延迟期病灶明显强化。结论：腹内侵袭性纤维瘤病的CT及MRI表现具有一定特征性,CT、MRI检查对该病有较高的诊断价值。     

肝脏炎性肌纤维母细胞瘤的影像表现

目的 探讨肝脏炎性肌纤维母细胞瘤(IMT)的影像表现特征,以提高影像诊断水平.方法 回顾性分析经手术病理证实的12例肝脏IMT的影像表现,其中12例均行CT扫描,2例行MR检查.结果12例单发病灶均位于肝右叶.6例肿块为实性,4例肿块为囊实混合性,2例表现为门静脉周围浸润性病灶.CT图像上呈实性或囊实性低密度影,MR T1WI为低信号,T2WI为略高信号;增强扫描肿块实性部分呈均匀或不均匀中重度强化,囊实混合性病灶周边及灶内实性间隔呈蜂窝样强化.结论CT及MR检查能为临床诊断及鉴别诊断肝脏IMT提供有价值的信息.     

腹部外硬纤维瘤的磁共振成像诊断

目的:了解腹部外硬纤维瘤的MR成像特征.方法:对经手术病理证实的10例硬纤维瘤的MR图像进行回顾性分析.所有的病例均采用Siemens Magnetom Vision 1.5T超导全身MR扫描仪,10例常规行T1WI和T2WI,9例行MR增强扫描.结果:10例腹部外硬纤维瘤中,韧带状纤维瘤1例;侵袭性纤维瘤病9例,其中颈项部3例,右肩背部3例,右大腿2例,左上臂2例.肿瘤的平均大小约为10 cm× 7 cm× 5 cm.除1例韧带状纤维瘤有包膜,边缘清楚外,其余肿块没有包膜,边界不清.所有肿块的信号欠均匀,在T1WI、T2WI及增强扫描像上可见低信号的纤维成分,肿块的非纤维成分在T1WI上与肌肉信号相同,在T2WI上的信号高于肌肉小于脂肪,呈明显强化.1例颈项部侵袭性纤维瘤病伴有邻近肌肉的广泛浸润,1例侵犯右肩胛骨部分内缘.结论:虽然硬纤维瘤与恶性肿瘤的MR信号有相似之处,但它在T1WI和T2WI上及增强扫描像上显示的低信号纤维成分,可以与软组织恶性肿瘤相鉴别.     

纤维组织源性肿瘤的CT与MRI表现与组织病理学对照

目的 探讨软组织侵袭性纤维瘤病、恶性纤维组织细胞瘤和黏液纤维肉瘤的CT与MRI表现及其组织病理性基础.方法 回顾性分析经手术病理证实的软组织侵袭性纤维瘤病(7例)、恶性纤维组织细胞瘤(9例)、黏液纤维肉瘤(3例)的CT和MRI表现,并与病理表现对照.结果 共检出肿瘤23个.侵袭性纤维瘤病7个,2个呈膨胀性生长,5个呈浸润性生长,CT像上呈等低密度,T1WI上呈低信号,T2WI/FS上信号明显增高.肿块内夹杂线样、条索状低信号影,增强扫描强化不均匀;恶性纤维组织细胞瘤12个,均呈分叶状,边界模糊,密度/信号不均匀,常伴囊变、坏死,增强扫描实质部分呈明显欠均匀强化.黏液纤维肉瘤4个,2个呈膨胀性生长,2个呈浸润性生长,密度/信号混杂,MRI可清晰显示黏液样基质的特征性信号,T2WI上呈高亮信号.结论 软组织侵袭性纤维瘤病、恶性纤维组织细胞瘤、黏液纤维肉瘤均为纤维组织来源肿瘤,影像学见瘤体内数量不同的线样低密度或低信号影,但又有各自影像特点,与其不同的病理学基础密切相关.MRI在反映病灶内成分方面优于CT.     

孤立性纤维瘤的影像诊断及病理分析

目的探讨不同部位孤立性纤维瘤(solitary fibrous tumor, SFT)的CT和MR特点。方法分析7例经病理证实为SFT的CT和MR表现。结果 7例术前均行CT检查,其中2例(眼眶)行MR检查,均为单发病灶;其中1例为恶性,位于右侧胸膜腔,其余均为良性。CT平扫实性成分以等密度为主,1例肿块边缘有低密度区;增强动脉期病灶强化差异较大,部分病灶轻度强化,部分病灶明显强化。部分瘤内及周边可见多发迂曲匍行的血管影;1例行延迟扫描,病灶进一步强化。MR图像上,T_1WI呈等-低信号,T_2WI呈略高信号,增强扫描肿块明显均匀强化。病理结果:肿块由多种排列方式的梭形细胞构成;免疫组化:cd34、cd99及b21-2阳性。结论 SFT是以实性成分为主的富血供肿块,较大病灶伴不同程度坏死、囊变,密度或信号不均匀,且明显不均匀强化。熟悉其影像特征可为其临床诊断提供参考依据。     

泌尿生殖系统孤立性纤维瘤的CT与MRI表现

目的 探讨泌尿生殖系统孤立性纤维瘤(SFT)的CT与MRI表现.方法 回顾性分析6例经手术病理证实的SFT患者的影像学资料,6例均行CT检查,1例行MRI扫描.结果 6例SFT中,肾脏、前列腺、睾丸、子宫、阴道及尿道各1例,均为单发圆形或类圆形肿块,5例边界清楚,1例边界欠清,大小约1.0 cm ×0.9 cm～ 15.2 cm×14.1 cm,平均约8.3 cm×7.1 cm.CT平扫3例呈等稍低均匀密度,3例呈不均匀等密度,伴斑片状低密度区;增强扫描动脉期肿块不均匀明显强化,延迟期肿块进一步持续强化,3例内见坏死无强化区;4例肿块内或表面可见粗大供血血管.MRI 1例T1WI呈等稍低信号,T2 WI呈等稍低信号,其内见小斑片状高信号及粗大的流空血管.结论 CT或MRI表现为孤立性、类圆形、实性肿块,边界清楚,密度或信号均匀或不均匀,增强动脉期明显不均匀强化,延迟期肿块进一步持续强化,尤其看到肿块内粗大的供血血管时,应考虑SFT可能.     

韧带样型纤维瘤病的X线平片、CT、MR表现及病理对照分析

目的 探讨韧带样型纤维瘤病(desmoid-type fibromatoses,DF)的影像学表现及其影像学诊断价值.方法 搜集经手术病理证实的DF患者16例,男7例,女9例.12例行CT检查(增强9例),4例行MRI检查(增强1例,4例均同时行X线平片检查).回顾分析韧带样纤维瘤病的CT和MRI表现,并与组织病理学进行对照分析.结果 16例患者共检出16个病灶,其中腹部外型11例,腹壁型3例,腹内型2例.CT平扫均表现为均匀略低软组织密度,边界不清;X线平片、CT骨骼病变显示呈膨胀性、溶骨性改变,病灶内有小梁形成,呈肥皂泡样,压迫性骨吸收破坏,常见不规则骨嵴,大多可见无钙化、骨化的软组织肿块.与肌肉信号相比,MRI T1 WI上呈等、稍低混杂信号;T2 WI呈高、低混杂信号,增强扫描呈中等以上不均匀强化;所有病灶内均可见条索状、片状T1WI及T2 WI上均呈低信号改变的区域,CT、MR无强化.结论 DF是一种具有侵袭性的良性肿瘤,X线平片可以观察骨质病变的整体形态,CT检查可以帮助了解骨质的破坏特点;T1 WI均呈低信号,T2 WI呈高、低混合信号,大部呈不均轻度强化,局部呈渐进性延迟强;T1WI、T2 WI示病变中斑点状及条带状低信号,MRI、CT增强扫描不强化是DT的特征性表现.因此,综合多种影像学检查方法对多数韧带性纤维瘤病能够作出正确的诊断.     

颈肩部韧带样型纤维瘤病CT与MRI表现

目的探讨颈肩部韧带样型纤维瘤病CT和MRI表现,了解其影像特征及其诊断价值。方法回顾性分析本院4例经手术病理证实的颈肩部韧带样型纤维瘤病CT及MRI表现,术前4例均行CT平扫加增强检查,2例行MRI检查。结果全部病例均表现为沿肌纤维长轴生长;1例呈卵圆形,3例呈不规则形侵袭性生长,边缘模糊;全部病例累及1块或多块肌肉及肌间隙,3例可见推移、压迫相邻的重要大血管,其中1例累及臂丛神经和侵袭相邻的椎体骨质,并包埋斜角肌和头臂血管。CT平扫1例密度均匀,低于肌肉,3例表现为不均匀低、等密度;增强后1例周边强化,3例呈不均匀轻度强化。MRI平扫T2WI肿瘤呈高、等混杂信号,内见斑片状或条带状分布的低信号,其中1例包埋低信号斜角肌。结论 CT和MRI可显示韧带样型纤维瘤病大小、形态、侵袭范围及与重要大血管的关系,肿瘤的MRI信号比CT密度更能反映有助于诊断的瘤内组织学成分。     

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.     

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.     

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.     

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.