单纯腹腔网膜脂肪突入食管裂孔多层螺旋CT多平面重组的表现及意义

目的:研究单纯腹腔网膜脂肪(PAOF)突入食管裂孔(EH)形态特征,探讨MSCT诊断EH单纯网膜脂肪疝的价值和限度。方法:回顾性分析2008年12月~2012年8月MSCT横断位发现EH膈上脂肪囊41例,获取亚毫米资料作MPR及MIP,观察脂肪囊、胃左动脉(LGA)形态特征及其与EH关系。结果:41例脂肪囊横断位呈类圆形15例,椭圆形17例和分叶形9例,23例囊内显示点条状血管影。MPR上11例脂肪囊呈狭基底形(疝囊形),30例呈广基底形(膨隆形),其底部均与腹腔网膜脂肪相连。囊内血管主要为LGA及其分支,其中9例LGA主干僵直,食管支附近呈对称性"∩"形突入胸腔,脂肪囊均为疝囊形;32例走向自然未进胸腔,30例脂肪囊呈膨隆形(χ2=19.988,P=0.031)。结论:PAOF突入EH横断位表现为膈上类圆/椭圆/分叶形脂肪囊;MPR上大致呈膨隆形和疝囊形两种形态,前者提示EH功能减退,后者结合LGA"∩"形突入胸腔征象有助于网膜脂肪疝诊断。     

多层螺旋CT多平面重组诊断食管裂孔网膜疝

目的 探讨MSCT多平面重组(MPR)诊断食管裂子网膜疝(EHOH)的价值.方法 5例经手术证实的EHOH均行MSCT平扫及增强检查,获取亚毫米数据作MPR及最大密度投影(MIP),在贲门部测量食管裂孔(EH)大小.以EH膈上脂肪囊与腹腔网膜脂肪相连、胃左动脉(GLA)穿EH及贲门位置正常作为EHOH诊断标准,由3位不知手术结果的高年资医生分别回顾性分析横断位和MPR图像进行判断.结果 5例横断位均显示EH膈上大小不等囊状脂肪密度影,其中椭圆形2例、类圆形2例及分叶形1例,内见点条状高密度影,增强有强化;1例伴转移性淋巴结肿大,1例伴小网膜转移,3例伴腹腔积液;2例判断准确.5例MPR直观显示脂肪囊与腹腔脂肪相连,4例GLA穿EH,主干僵直和食管支附近呈“∩”形特征形态;5例均作出准确诊断.结论 MSCT MPR清晰显示EH膈上脂肪囊与腹腔网膜脂肪相连及GLA穿EH的形态特征,对EHOH诊断具有重要意义.     

MSCT多平面重组诊断非裂孔性膈疝的价值

目的 探讨多层螺旋CT(MSCT)多平面重组(multiple planar reconstruction,MPR)诊断非裂孔性膈疝(nonhiatus diaphragmatic hernia,NHDH)的价值.资料与方法 回顾分析23例NHDH患者的影像资料,其中Bochdalek疝8例,Morgagni疝3例(1例经手术证实),创伤性膈疝9例(均经手术证实),医源性膈疝3例.23例均行MSCT容积扫描,由3位不知手术结果的高年资医师先后回顾分析MSCT横断位及MPR表现,观察有无横膈异常升高、膈肌连续性中断缺损、"颈圈征"及"内脏依靠征"等征象作为NHDH诊断依据,并分别作出判断.结果 22例MSCT横断位及MPR图像见膈上大小不等的疝囊及内容物,膈肌连续性中断.横断位显示13例,MPR显示22例(t=4.97,P＜0.05).2例Bochdalek疝误诊为膈肌衰老,1例误诊为脂肪瘤,1例较大Morgagni疝误诊为脂肪瘤,4例创伤性膈疝首诊提示诊断,2例医源性膈疝漏诊,术前诊断率56.5%;术后回顾分析横断位14例(60.7%)提示NHDH,结合MPR 21例(91.3%)提示NHDH诊断(t=4.33,P＜0.05).结论 MSCT MPR能够清晰显示NHDH膈肌连续性中断及膈上疝囊与膈肌的关系,对诊断具有决定意义.     

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.     

多层螺旋CT在成人肠套叠诊断中的应用

目的 探讨成人肠套叠的多层螺旋CT(MSCT)直接征象和轴位薄层结合多平面重组技术(MPR)对成人肠套叠及其原发病的诊断价值.方法 回顾性分析经手术和病理证实的21例成人肠套叠的MSCT直接征象,并比较应用轴位薄层结合MPR与单纯应用轴位厚层图像对成人肠套叠及其原发病诊断的准确性.结果 应用轴位厚层显示靶征6例,双肠管征5例,不典型征象如狗嘴征、"8"字征和香蕉征共6例,肿块征4例,血管卷入征10例;确诊肠套叠13例(13/21,61.9%)、原发病13例(13/21,61.9%).采用轴位薄层结合MPR显示靶征14例,双肠管征18例,肿块征3例,血管卷入征15例;确诊肠套叠19例(19/21,90.5%)、原发病15例(15/21,71.4%).轴位薄层结合MPR较轴位厚层对成人肠套叠的诊断准确性差异有统计学意义(P<0.05),但对其原发病的诊断准确性差异无统计学意义(P>0.05).结论 靶征、双肠管征和血管卷入征是成人肠套叠的特异性直接MSCT征象;轴位薄层结合MPR对成人肠套叠的诊断有重要价值,应常规实施.     

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。     

MSCTA在儿童肠旋转不良伴中肠扭转中的诊断价值

目的:探讨MSCT血管成像(MSCTA)在儿童肠旋转不良伴中肠扭转中的诊断价值.方法:回顾性分析经手术证实的11例肠旋转不良伴中肠扭转患儿的临床资料和CT表现,其中男8例,女3例,年龄13天～8岁,中位年龄2.3岁.11例患儿均行CT平扫及增强检查,并采用多平面重组(MPR)、最大密度投影(MIP)、容积再现(VR)技术对图像进行后处理.结果:10例患儿表现为"漩涡征",1例患儿表现为"换位征",6例患儿可见"鸟喙征",5例患儿表现为肠管扩张、积液,4例可见肠壁及肠系膜肿胀,4例可见腹盆腔积液.结论:MSCTA对诊断儿童肠旋转不良伴中肠扭转具有重要价值.     

非裂孔性膈疝膈肌破口形态MSCT多平面重组观察

目的 探讨非裂孔性膈疝膈肌破口多层螺旋CT(MSCT)多平面重组(mutiple planar-reconstraction,MPR)成像方法及其形态特征.资料与方法 回顾分析53例非裂孔性膈疝患者的影像资料,其中Bochdalek疝18例,Morgagni疝8例(4例经手术证实),创伤性膈疝(traumatic diaphragmatic hernia,TDH)21例(均经手术证实),医源性膈疝(iatrogenic diaphragmatic hernia,IDH)6例(2例经手术证实).53例均行MSCT容积扫描,采用MPR倾斜横断位直接显示和冠状或矢状位重组测量横断位定点描绘(简称测量法)间接显示两种方法,观察膈肌破口大小、形态特征及显示情况并作比较.结果 各类非裂孔性膈疝破口形态主要有类圆形和椭圆形/梭形两类.MPR倾斜横断位及测量法分别显示Bochdalek疝12例(66.7%)和14例(77.8%),Morgagni疝4例(50%)和5例(62.5%),TDH 17例(80.9%)和18例(85.7%),IDH 6例(100%)和6例(100%);总显示率分别为73.6%和81.1%(χ2=1.08,P>0.05).非创伤类膈疝破口形态主要为椭网形/梭形,创伤类膈疝(IDH属于创伤类膈疝)主要为类圆形(P<0.05).TDH破口长短径显著大于其他各类膈疝(P<0.05).10例两种方法均未能显示较完整膈疝破口形态.结论 MPR倾斜横断位和测量法能直接或间接显示绝大多数各类非裂孔性膈疝膈肌破口形态特征,可为临床评估病情、指导手术提供比较直观的影像资料.     

多层螺旋CT后处理技术对孤立型细支气管肺泡癌的诊断价值

目的 探讨多层螺旋CT三维重组对孤立型细支气管肺泡癌(bmnchioloalveolar carcinoma,BAC)的诊断价值.资料与方法 经病理证实的孤立型BAC 35例,分析高分辨率CT(HRCT)扫描、多平面重组(MPR)和容积再现(VR)技术对孤立型BAC基本征象的显示价值,并与常规横断位图像对比分析.结果 35 例孤立型BAC根据CT图像上病灶密度表现将病灶分为3种类型:(1)单纯磨玻璃密度结节(8例);(2)混杂密度结节(20例);(3)单纯实性密度结节(7例).HRCT、MPR及VR在湿示孤立型BAC的空泡征、纯磨玻璃征、环晕征、分叶征、毛刺征、胸膜凹陷征及支气管血管集束征方面优于常规横断位.结论 HRCT及三维重组,较常规横断位扫描能更准确地显示孤立型BAC的内部细微结构及周围形态改变,对孤立型BAG诊断具有重要价值.     

MSCT多平面重组诊断单纯性横膈网膜疝

目的探讨MSCT多平面重组（multipleplanarreconstruction,MPR）诊断单纯性横膈网膜疝（simpleomentaldiaphragmatichernia,SODH）的价值。方法31例SODH均行MSCT容积扫描并作亚毫米重组,3名不知手术结果的高年资医师回顾性分析横断位和MPR图像,以发现膈肌中断缺损、膈上脂肪疝囊、“狭颈征”及“阳性血管征”作为诊断SODH依据;横断位及MPR征象显示及诊断差异采用x。检验。结果31例SODH中Bochdalek疝15例、Morgagni疝4例、医源性膈疝3例、食管裂孔疝6例及腔静脉裂孔疝3例,膈肌中断缺损、膈上疝囊、“狭颈征”及“阳性血管征”横轴位和MPR依次分别显示：6例和22例6．67,P〈O．01）、31例和31例、6例和28例（x2=31．52,Pd0．01）及3例和11例（x2=5．90,Pd0．05）。横轴位诊断12例,MPR全部明确诊断（x2=27．40,P〈0．01）。结论MSCTMPR清晰显示SODH多种特征性征象,对诊断具有决定意义。     

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.     

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.     

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.     

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.     

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.