螺旋CT对肠扭转的诊断价值

目的：探讨螺旋CT对肠扭转的诊断价值。方法：回顾性分析11例术前CT明确诊断并经手术证实为肠扭转的临床及影像资料。结果：11例肠扭转CT均正确诊断,其中6例为360°肠扭转,4例为270°肠扭转,1例为180°肠扭转。除全部11例都有通常的肠梗阻征象外,主要征象还有“漩涡征”（9／11）、“靶环征”（4／11）及“鸟喙征”（10／11）,肠系膜血管也可以形成“漩涡征”（11／11）。结论：螺旋CT对肠扭转具有重要的临床价值,尤其是肠系膜血管的“漩涡征”。     

64层螺旋CT在小肠扭转中的诊断价值

目的探讨64层螺旋CT在小肠扭转中的诊断价值。资料与方法对7例术前CT诊断为小肠扭转,其中5例经手术证实的病例资料进行回顾性分析。主要重组方法为多平面重组(MPR)、最大密度投影(MIP)及容积再现(VR)。结果7例均正确诊断,主要征象有肠管的漩涡征(4例)、血管的漩涡征(6例)、靶环征或双晕征(6例)、鸟喙征(4例)、缆绳征(7例)、肠系膜水肿(7例)、腹腔积液(4例)。结论肠系膜血管的漩涡征是诊断肠扭转的特异性征象。64层螺旋CT扫描及重组图像对小肠扭转显示更直观、明确,具有重要的诊断价值。     

成人肠扭转MSCT的诊断价值

目的 探讨成人肠扭转多层螺旋CT(MSCT)征象.方法 回顾性分析72例经手术病理确诊为成人肠扭转患者的16层MSCT腹部检查影像资料.结果 有血管的漩涡征70例、肠管的漩涡征58例、靶环征35例、鸟喙征37例.结论 MSCT检查对成人肠扭转的诊断、治疗具有重要指导作用,肠系膜血管的“漩涡征”是诊断肠扭转的特异性征象.     

多层螺旋CT对肠扭转的诊断价值

目的探讨多层螺旋CT(MSCT)对肠扭转的诊断价值。方法收集急腹症MSCT双期增强扫描病例80例,其中10例患者图像经多平面重组(MPR)及肠系膜血管最大密度投影(MIP)处理,诊断为肠扭转。结果MSCT诊断10例肠扭转,主要征象有肠系膜血管“漩涡征”10例,肠管“漩涡征”5例,靶环征或双晕征5例,肠系膜上动脉、静脉(SMA、SMV)换位征3例,鸟喙征4例,SMV血栓形成2例,腹水征10例。诊断均经手术证实。结论MSCT双期增强扫描及多平面重组(MPR)与肠系膜血管最大密度投影(MIP)对肠扭转的诊断有重要价值。     

螺旋CT对小肠内疝的诊断价值

目的提高螺旋CT对小肠内疝的诊断率。方法对11例经手术证实且术前CT资料完整的小肠内疝患者进行回顾性分析，CT主要后处理方法有多平面重组（MPR）、滑动薄层块最大密度投影（STS-MIP）重组。结果11例小肠内疝CT诊断正确。左侧十二指肠旁内疝表现为胃和胰之间一囊性或囊实性肿块；肠聚集、移位及拥挤、拉伸；肠系膜走行异常，并可见血管充盈增粗，其他肠段移位；疝口、肠梗阻、小肠内疝伴扭转时，还可以显示肠管及附属肠系膜血管的“漩涡征”。结论螺旋CT扫描及其后处理技术对小肠内疝具有重要的临床价值。     

肠旋转不良伴中肠扭转的CT诊断

目的 评价CT对肠旋转不良伴中肠扭转(volvulus in intestinal malrotation, VIM)的诊断价值.方法 对12例术前CT明确诊断并经手术证实的VIM患者的临床CT资料进行回顾性分析.结果肠系膜根部"漩涡征"12例,"鸟喙征"9例,"靶环征"3例,3例合并肠管淤张积液、肠系膜水肿及腹水.结论 VIM具有特异性CT征象,CT检查对诊断VIM具有重要价值.     

腹内疝伴肠扭转的螺旋CT诊断

目的:探讨螺旋CT对腹内疝及伴发肠扭转的诊断价值.方法:对10例手术证实的腹内疝病例的CT资料进行回顾性分析,CT检查采用平扫及双期增强,并进行VR、MPR及M1P等后处理.结果:10例腹内疝中,8例有腹部手术史,10例均表现为肠梗阻,8例显示疝口,并有肠聚集、移位、肠系膜血管走形异常.伴发肠扭转7例,显示肠管和血管的“漩涡征”,5例见“鸟喙征”,3例见“同心圆征”,4例出现肠绞窄,表现为肠管强化减弱、肠壁水肿、腹水.结论:螺旋CT增强扫描和多种方法重组对腹内疝伴发肠扭转具有重要的诊断价值,及时诊断对患者的预后具有重要的作用.     

小肠扭转的螺旋CT诊断

目的:探讨螺旋CT对小肠扭转的诊断价值.方法:对8例经手术证实小肠扭转患者的病例资料进行回顾性分析.1例患者行CT平扫,7例行CT平扫和双期增强扫描,并进行图像后处理,包括容积再现(VR)、多平面重组(MPR)和最大密度投影(MIP).结果:8例中7例有肠管和血管的漩涡征,5例有鸟喙征,2例见同心圆征,4例显示肠管壁强化减弱、肠壁水肿和腹水.结论:肠管和血管的漩涡征是诊断小肠扭转的特征性征象,同心圆征、肠管强化减弱、肠壁水肿和腹水的出现,则高度提示绞窄性肠梗阻;螺旋CT增强扫描和图像重组可对小肠扭转做出准确的定位和定性诊断.     

绞窄性肠梗阻的螺旋CT增强扫描征象分析

目的:分析螺旋CT增强扫描图像上绞窄性肠梗阻的征象,提高对绞窄性肠梗阻术前诊断的准确性.方法:64例手术证实的绞窄性肠梗阻病例纳入研究,男43例,女21例,年龄23～72岁,平均42岁.采用单排螺旋CT进行全腹部扫描,对比剂以2～3ml/s速度注射,注射后60s扫描,层厚10mm.参照术中所见,回顾性分析上述CT资料,包括:①间接征象:肠腔扩张积液,肠壁增厚及肠壁密度改变(靶征),肠系膜脂肪水肿及渗出(缆绳征),肠系膜血管增粗并肠系膜扭曲(漩涡征),肠壁间、肠系膜间及门静脉积气,腹水;②直接征象:肠系膜上动脉或上静脉充盈缺损.结果:正确诊断54例,正确率82.8％.CT显示肠腔扩张积液47例(73％),其中6例积液呈高密度提示肠腔内积血(9.3％);肠壁水肿增厚19例(29.6％),其中11例增强后肠壁密度不匀,呈“靶征”(17％),8例肌壁未见强化(12.5％);肠系膜脂肪水肿及渗出(缆绳征)43例(67％),肠系膜血管增粗并肠系膜扭曲呈“漩涡”状9例(14％),肠壁间积气、肠系膜积气各1例,门静脉积气2例,腹水31例(48.4％).肠系膜上动脉或上静脉充盈缺损3例.结论:绞窄性肠梗阻CT表现有一定特征,可做出提示性诊断.     

肠扭转的CT诊断(附16例分析)

目的:探讨肠扭转CT平扫的影像学特征.方法:对16例经手术证实的肠扭转患者的CT平扫检查及其影像学表现进行了分析.结果:肠扭转CT平扫的主要征象为:①直接征象:肠袢呈C形15例,肠系膜血管扭曲征16例,远端肠管呈鸟嘴征13例,漩涡征6例;②间接征象:扭转肠袢内积液、积气者14例(其中单纯肠管内积液者6例),近端肠管见液平面者12例,腹膜腔内积液者3例.结论:CT平扫对肠扭转的早期诊断及指导临床治疗有重要价值.     

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.     

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.     

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     

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.     

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.     

Pericerebellar fluid collections in infancy,sequelae of birth injury? A retrospective CT study

Summary Retrospective analysis of axial CT scans from 600 consecutive pediatric patients revealed 37 patients (6%) with abnormal low density pericerebellar spaces. Fourteen of these 37 patients (38%) were diagnosed as cerebellar atrophy, whereas 23 of the 37 patients (62%) were diagnosed as mass-like pericerebellar fluid collections. Detailed analysis of the morphology of these spaces suggests that the CT criteria proposed in this paper distinguish between (a) those low attenuation pericerebellar spaces that represent cisternal dilatation caused by cerebellar atrophy (Group I — Atrophy) and (b) those low attenuation pericerebellar spaces that represent low density mass-like collections of fluid which distort a relatively normal cerebellum (Group II — Collections). Analysis of the medical records of the patients in Group II — Collections reveal a high incidence of prematurity, developmental delay, difficult birth and head trauma, possibly indicating that such collections represent sequelae of birth.     

Localized proton MR spectroscopy of the brain in children

Small-voxel (3.0–8.0 cm³), magnetic resonance (MR) imaging–guided proton MR spectroscopy was performed in 54 patients (aged 6 days to 19 years) with intracranial masses (n = 16), neurodegenerative disorders (n = 34), and other neurologic diseases (n = 4) and in 23 age-matched control subjects without brain disease. A combined short TE (18 msec) stimulatedecho acquisition mode (STEAM) and long TE (135 and/or 270 msec) spin-echo point-resolved spatially localized spectroscopy (PRESS) protocol, using designed radio-frequency pulses, was performed at 1.5 T. STEAM spectra revealed short T2 and/or strongly coupled metabolites; prominent resonances were obtained from N-acetyl aspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Lactate was well resolved with the long TE PRESS sequence. Intracranial tumors were readily differentiated from cerebrospinal fluid (CSF) collections. All tumors showed low NAA, high Cho, and reduced tCr levels. Neurodegenerative disorders showed low or absent NAA levels and enhanced mobile lipid, glutamate and glutamine, and inositol levels, consistent with neuronal loss, gliosis, demyelination, and amino acid neuro-toxicity. Preliminary experience indicates that proton MR spectroscopy can contribute in the evaluation of central nervous system abnormalities of infants and children.