肾上腺肿瘤的螺旋CT诊断及鉴别诊断

目的：总结肾上腺肿瘤的CT表现及特征,评价螺旋CT对肾上腺肿瘤的诊断和鉴别诊断价值。方法：回顾性分析36例经手术病理证实的各类肾上腺肿瘤的CT征象,提出诊断与鉴别诊断要求。结果：皮质腺瘤14例,大小、密度中等;皮质腺癌4例,肿块较大不规则,密度不均匀,中心有低密度坏死;嗜铬细胞瘤9例,单侧瘤体较大,平扫密度不均匀,实质部分强化明显;髓质脂肪瘤3例,低密度的脂肪显示是其特征性CT表现;转移瘤5例,多为肺癌转移,肿块呈圆形或不规则形,密度不均匀,中等强化;肾上腺囊肿1例,凹值低而均匀,壁薄规则。结论：肾上腺肿瘤CT表现有一定的特征性,认真分析,结合临床及生化检查,可对其作出定性诊断。     

肾上腺肿瘤的MSCT多期增强扫描应用价值

目的 探讨MSCT多期增强扫描对肾上腺肿瘤的诊断及鉴别价值.方法 收集经病理证实的肾上腺肿瘤患者70例共72个病灶的资料,包括醛固酮腺瘤23个、皮质醇腺瘤18个、嗜铬细胞瘤17个及转移瘤14个.结果 醛固酮腺瘤平扫CT均值≤20 HU,21个呈轻度均匀强化.皮质醇腺瘤平扫CT均值≤25 HU,12个呈中度均匀强化;15个嗜铬细胞瘤呈重度不均强化;12个转移瘤呈中度不均强化.动脉期强化率:醛固酮腺瘤＞嗜铬细胞瘤＞皮质醇腺瘤＞转移瘤;静脉期强化率:醛固酮腺瘤＞皮质醇腺瘤＞转移瘤,嗜铬细胞瘤＞转移瘤;相对造影剂清除率:醛固酮腺瘤＞皮质醇腺瘤＞嗜铬细胞瘤＞转移瘤.结论 肾上腺4种常见肿瘤的MSCT平扫、增强密度特征及其强化率、清除率存在差异,可作为这些肿瘤诊断及鉴别诊断的参考指标.     

肾上腺肿瘤的CT诊断

目的 总结肾上腺肿瘤的CT表现及特征，探讨鉴别诊断依据。资料与方法 搜集有完整CT资料并经手术病理证实的肾上腺肿瘤49例，分析其大小、边缘、形态、密度及强化特征。结果 49例中，皮质腺瘤19例，肿瘤直径为1．0～4．0cm，有包膜，密度均匀但较低，强化较轻。皮质腺癌4例，表现为不规则、分叶状、密度不均匀、环状强化的肿块。嗜铬细胞瘤14例，单侧，良性，瘤体大，平扫不均匀，实质强化明显，低密度区无强化。髓质脂肪瘤4例，低密度的脂肪密度区是其特征性CT表现。转移瘤5例，均为肺癌转移，多呈类圆形或不规则形肿块，密度均匀或不均匀，强化较明显。畸胎瘤3例，CT可见脂肪密度和钙化。结论 肾上腺肿瘤CT表现有一定的特征性，结合临床及生化检查，做出诊断是有可能的。对于体积较大的肾上腺肿瘤，还需与其他腹膜后肿瘤相鉴别。     

肾上腺肿瘤的CT诊断(附46例分析)

目的:探讨肾上腺肿瘤在CT上的表现特点,以提高对该部位肿瘤的认识。方法:收集46例肾上腺肿瘤,回顾分析CT特征,对照病理结果进行讨论。结果:46例中,皮质腺瘤21例,多数较小,边缘光滑,轻度强化;转移瘤7例,单侧或双侧,密度均匀或不均匀;嗜铬细胞瘤6例,肿块一般较大,密度不均,增强后实质部分强化明显;髓性脂肪瘤6例,瘤内脂肪组织为其特征;皮质腺癌3例,较大肿块,直径一般大于7 cm,密度不均;肾上腺囊肿2例,边缘光滑,均匀水样密度的囊性占位,增强扫描无强化;非何杰金淋巴瘤1例,双侧发生,软组织密度肿块,强化较均匀。结论:肾上腺肿瘤CT表现各有特征,结合临床表现和生化检查可作出较为正确的诊断。     

CT在肾嗜酸细胞腺瘤诊断中应用(附6例分析)

目的 探讨CT对肾嗜酸细胞腺瘤术前诊断的可能性.方法 回顾性分析经手术、病理证实的6例肾嗜酸细胞腺瘤的动态增强CT表现,根据病变部位、大小、密度、边缘、强化方式,测量病变平扫及CT动态增强各期的CT值.结果 CT平扫:6例肾嗜酸细胞腺瘤平均CT值35HU,3例密度均匀,1例病灶内见瘢痕样低密度影,2例密度不均匀,其中1例见多发小囊状低密度灶.动态增强CT:6例病灶实质部分CT值在皮质期平均94HU、实质期平均110HU;1例病灶的中心瘢痕呈轻微强化,CT值30HU,1例多发小囊状低密度灶分隔呈持续强化;1例增强扫描呈“节段性强化逆转”,3例包膜轻度延迟强化.结论 CT检查是肾嗜酸细胞腺瘤的首选检查方法,动态增强CT肿瘤实质部分明显持续性强化、肿瘤内星状瘢痕并延迟强化、部分病灶可显示完整并延迟强化的包膜等典型征象有助于肾嗜酸细胞腺瘤的术前诊断并与肾癌相鉴别.     

肾上腺肿瘤的CT诊断

作者分析了36例病理证实的肾上腺肿瘤CT表现,其中27例为肾上腺皮质腺瘤(13例临床表现为原发性醛固酮增多症,12例为Cushing氏综合征,2例为无功能腺瘤),1例皮质腺癌,8例嗜铬细胞瘤。13例临床表现为原发性醛固酮增多症的肾上腺皮质腺瘤CT值为-18～13HU(平均1.8±9.9HU)低于表现为Cushing氏综合征者的-0.4～     

多发嗜铬细胞瘤的CT诊断价值

目的:分析多发嗜铬细胞瘤的影像学表现及动态增强特征,以提高其诊断准确性。方法:经手术病理证实的多发嗜铬细胞瘤9例,其中双侧肾上腺嗜铬细胞瘤7例,Von Hippel-Lindau病1例,腹膜后副神经节瘤并膀胱嗜铬细胞瘤1例。术前经螺旋CT和多层螺旋CT平扫、动脉期(30s)和门脉期(70～80s)扫描。对比剂采用欧乃派克或优维显,注射流率3ml/s。仔细复习CT扫描结果并与手术病理作回顾性对照分析。结果:9例嗜铬细胞瘤共18个病灶中,双侧肾上腺嗜铬细胞瘤7例,双侧肾上腺嗜铬细胞瘤并胰腺神经内分泌瘤和肾细胞肾癌1例(Von Hippel-Lindau病),腹膜后副神经节瘤并膀胱恶性嗜铬细胞瘤1例。良性病灶13个,恶性病灶5个。肿瘤呈圆形或椭圆形15个,不规则形3个。直径3.2～13.7cm,平均5.6cm。病灶直径<5.0cm3个,5.0～10.0cm13个,>10cm2个。肿瘤实质成分平扫CT值为34.2～53.0HU,平均42.7HU;动脉期CT值63.7～91.5HU,平均80.7HU;门脉期CT值75.1～126.4HU,平均98.1HU。8例双侧肾上腺嗜铬细胞瘤16个病灶中,6例两侧病灶大小、形态、密度、动态增强强化程度和强化方式相仿,2例两侧大小不同,坏死、囊变不同,但动态增强强化程度和强化方式相仿。结论:多发嗜铬细胞瘤包括双侧肾上腺嗜铬细胞瘤、副神经节瘤和脏器嗜铬细胞瘤,多位于双侧肾上腺,CT表现与肾上腺嗜铬细胞瘤相仿,同一病例不同肿瘤的大小、形态、坏死囊变、动态增强强化方式和强化程度相仿,少数肿瘤大小不同,坏死囊变存在差异。     

儿童不典型肾上腺肿瘤的影像学分析

目的 分析7例儿童不典型的肾上腺肿瘤的CT和MRI表现,以提高对儿童肾上腺肿瘤的鉴别诊断水平. 资料与方法回顾性分析经手术和病理证实的儿童肾上腺肿瘤7例,复习其CT和MRI表现并与手术病理对照分析.结果 Ⅰ级神经母细胞瘤1例,CT表现为均匀稍低密度肿块;单纯肾上腺囊肿1例,表现为均匀低密度囊性肿块,无强化;囊肿伴出血1例,囊壁嗜铬母细胞增生,表现为T1WI及T2WI高信号,增强后囊壁环形强化;肾上腺髓外造血1例,表现为均匀低密度肿块,轻度强化;皮质腺瘤1例,表现为均匀软组织密度肿块,增强后动脉期明显强化,静脉期强化减弱;肾上腺皮质癌2例,1例密度不均匀,增强后肿瘤实性成分强化持续时间较长,另1例MRI表现为轻度均匀强化.结论 除单纯囊肿外,儿童肾上腺肿瘤影像学表现缺乏特异性,确诊需与临床及病理结合.     

肾上腺肿瘤的CT诊断

目的：探讨ＣＴ对肾上腺肿瘤的诊断价值。材料与方法：回顾性分析９４例经手术病理证实的各类肾上腺肿瘤,观察其ＣＴ征象,提出诊断和鉴别诊断要点。结果：醛固酮腺瘤肿块小,密度低;皮质醇腺瘤中等大小,中等密度;肾上腺原性腺综合征肿块较大,密度均匀;无机能性腺瘤与神经节瘤相似表现为肿块较大,密度略低;肾上腺皮质腺癌肿巨大,呈不规则低密度肾上腺转移癌肿块较在,密度不均匀,嗜铬细胞瘤肿块较大,密度不均匀。结论：Ｃ     

肾上腺肿瘤的CT和MRI诊断

目的：探讨肾上腺肿瘤的CT和MRI影像学特点。方法：回顾分析经临床、手术病理证实的40例肾上腺肿瘤的CT资料和其中10例。MRI资料，观察其CT和MRI征象，提出诊断和鉴别诊断要点。结果：40例中，腺瘤16例，其中Cushing腺瘤8例，直径2．0～3．0cm的密度均匀的肿块，其信号与肝脏信号类似；Conn腺瘤6例，直径1．0～2．0cm的均一水样密度肿块；2例腺瘤无症状。皮质腺癌7例，呈巨大不规则的不均匀密度或信号肿块。嗜铬细胞瘤7例，较大的不均匀密度或信号肿块，实体部分明显强化。转移瘤8例，双侧或单侧肿块，T2WI明显高信号。髓性脂肪瘤1例，不均质肿块内有显著的脂肪组织密度或信号。淋巴管囊肿1例，不强化均一水样密度或信号的肿块。结论：肾上腺肿瘤CT和MRI表现有一定的特征，结合临床及生化检查，能对其做出定性诊断。     

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.     

MR imaging of disorders of the brachial plexus

The authors evaluated 64 consecutive patients with suspected brachial plexus (BP) abnormalities of diverse cause with magnetic resonance (MR) imaging, using the body coil and a standardized protocol. Of the 43 patients for whom follow-up was available, 25 were suspected of having neoplastic involvement of the BP, nine had sustained injuries, and nine presented with BP symptoms of uncertain cause. MR imaging was 63% sensitive, 100% specific, and 77% accurate in demonstrating the abnormality in this diverse patient population. When patients with neoplastic and traumatic disorders were considered separately, sensitivity increased to 81%, accuracy to 88%, and specificity remained unchanged. In the patients with a clinical diagnosis of idiopathic or viral plexitis, the MR imaging findings were normal, serving to exclude other structural abnormalities. It is concluded that MR imaging is valuable in the assessment of a wide range of BP disorders.     

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.     

MR imaging characteristics of noncancerous lesions of the prostate.

Radical prostatectomy specimens from 53 men with clinical stage A or B prostate cancer were retrospectively reviewed and compared with correlative axial T2-weighted magnetic resonance (MR) images obtained just before surgery. Non-cancerous lesions were evaluated for signal intensity and location. Focal high-signal-intensity areas (n = 72) were present in 81% of patients. The 26% of lesions seen in the central gland all correlated with cystic atrophy. Of the 53 lesions seen in the peripheral prostate, 47 (89%) were cystic atrophy without associated cancer, four (7.5%) cystic atrophy with cancer, and two (3.8%) focal inflammation. Focal low-signal-intensity areas (n = 42) were present in 60% of patients. Of the 31% of lesions in the central prostate, one-fifth correlated with benign prostatic hyperplasia (BPH) and four-fifths with fibrous tissue. Of the 69% of peripheral lesions, 83% corresponded to fibrous tissue, 10% to BPH, and 7% to normal tissue. Mixed lesions (n = 42) were present in 64% of patients; 86% of these were located centrally and 14% peripherally. All mixed central lesions were BPH; the peripheral lesions were areas of combined cystic atrophy and fibrosis. BPH of low or mixed signal intensity can extend into the peripheral prostate and mimic cancer. High-intensity cystic atrophy associated with cancer can mimic normal tissue.     

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.     

Influence of in vivo copper on MR images of the liver in rats

To investigate the effects of in vivo copper on magnetic resonance (MR) images, the authors studied Long-Evans cinnamon rats, which develop hepatitis and hepatocellular carcinoma as a result of abnormal copper metabolism. The livers of the rats were imaged before hepatitis developed; the absence of hepatic disease was confirmed histopathologically. The copper that accumulated in the liver of the rats was thought to exist in the form of divalent ions, which were suspected of reducing the T1 and T2 of neighboring protons. However, the signal intensities of the liver on T1- and T2*-weighted images did not change, suggesting that in vivo copper, even when accumulated abnormally, does not influence the signal intensity of MR images.     

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.     

Percutaneous needle biopsy of the spine

The purpose of this review article is to provide a brief overview of the recent literature on the two main types of percutaneous biopsy methods done in the spinal column: fine needle aspiration biopsy (FNAB) and core needle biopsy (CNB). FNAB is the process of obtaining a sample of cells and bits of tissue for examination by applying suction through a fine needle attached to a syringe. Core needle biopsy involves extracting a cylindrical sample of tissue using a large, hollow needle. The decision for needle biopsy is a joint effort between the clinician, pathologist, radiologist, surgeon, and patient. Specific techniques and approaches with varying needle systems are described for each spinal region. Percutaneous image-guided spine biopsy is a safe and effective procedure. It is the procedure of choice in definitive diagnosis of pathologic lesions of the spine.     

Techniques for high-resolution MR imaging of atherosclerotic plaque

Atherosclerotic cardiovascular disease is the most common cause of death in the United States. Investigation of atherosclerotic plaque morphology and composition is important because the findings may be useful in predicting prognosis or response to therapy. This study presents high-resolution magnetic resonance (MR) imaging techniques developed on a 1.5-T whole-body imager with a custom-built surface coil, for characterizing the composition and morphology of plaque removed at carotid endarterectomy. The initial comparison of MR imaging and histologic results showed good correlation. In conjunction with MR angiography, these techniques could be used in in vivo imaging to define the size, location, and contents of atherosclerotic plaque at the carotid bifurcation.