Nuclear medicine and molecular imaging of the pediatric chest: current practical imaging assessment

In the chest, the indications for nuclear medicine studies are broader and more varied in children than in adults. In children, nuclear medicine studies are used to evaluate congenital and developmental disorders of the chest, as well as diseases more typical of adults. In the chest, pediatric nuclear medicine uses the same radiopharmaceuticals and imaging techniques as used in adults to evaluate cardiac and pulmonary disease, aerodigestive disorders, and pediatric malignancies. The introduction of PET (mostly using (18)F-FDG) has transformed pediatric nuclear oncology, particular for imaging malignancies in the chest.     

Vascular imaging in the elderly

Though a myriad of vascular conditions affect the elderly, atherosclerosis remains the most common vascular disorder, followed by venous thromboembolism and varicose veins. In this article, the authors discuss the imaging of atherosclerosis affecting various vascular territories and pay special attention to the elderly population. The authors also discuss imaging findings of segmental arterial mediolysis, giant cell arteritis, and venous thromboembolism.     

磁共振扩散加权和灌注成像对超急性期脑梗死影像半暗带的研究

目的　应用扩散加权成像 (diffusionweightedimaging ,DWI)和灌注成像 (perfusionimaging,PI)观察超急性期脑梗死影像半暗带的转归。方法　对 41例发病 2～ 72h(其中 3 1例发病 <6h ,为超急性期脑梗死 ;10例发病 7～ 72h ,为急性期脑梗死 )的脑梗死患者行MR扫描 ,并使用平面回波技术(echoplanarimaging ,EPI)进行DWI检查。全部病例在治疗后 1～ 2个月行MRI复查。将发病时DWI呈异常高信号 ,而于复查时T2 WI呈正常信号的脑组织定义为影像半暗带 ;将发病时DWI呈高信号而复查时T2 WI亦为高信号的组织定义为病灶中心区。以年轮状方式由外向内测定上述 2个区域的表观扩散系数 (apparentdiffusioncoefficient,ADC)值。同时 ,对发病 <6h的患者中的 17例行表观扩散系数比率 (apparentdiffusioncoefficientratio,ADCR)测定 ,并对 10例行动态对比剂增强血流灌注成像。结果　 3 1例超急性期脑梗死在首次发病时T2 WI未能提示梗死灶 ,19例仅提示病变处血管流空信号消失 ;10例急性期脑梗死T2 WI均可见局部异常高信号 ;同一时期DWI于全部 41例明确显示梗死灶。超急性期脑梗死经治疗后 ,最终梗死灶的面积较首次DWI上异常高信号区域的面积减小 (t =17,P <0 0 1)。病灶中心区周边的影像半暗带呈可逆性转归。起病初期DWI上     

MR imaging of the brain: metabolic and toxic white matter diseases

Metabolic disorders of the brain are rare, complex and confusing. The diagnostic modality of choice nowadays is MRI. The high diagnostic sensitivity, however, is coupled with a lack of specificity and usually results in the depiction of similar appearing but clinically diverse white matter processes. For this reason it is essential to perform the MRI as early as possible during the course of the disease and to keep in close contact to the referring clinician to optimize image interpretation. Another precondition is to know the natural course of brain myelination and to know how this appears on the individual MR machine with different parameters. In some diseases like phenylketonuria MRI seems to be an excellent tool to monitor dietary treatment and patient compliance. In patients after radio- and / or chemotherapy MRI reveals the radiation induced leucencephalopathy and can usually differentiate between a recurrent malignancy.     

MR imaging of the small bowel in Crohn's disease

MR and CT techniques optimized for small bowel imaging are playing an increasing role in the evaluation of small bowel disorders. Several studies have shown the advantage of these techniques over tradition barium fluoroscopic examinations secondary to improvements in spatial and temporal resolution combined with improved bowel distending agents. The preference of MR vs. CT has been geographical and based on expertise and public policy. With the increasing awareness of radiation exposure, there has been a more global interest in implementing techniques that either reduce or eliminate radiation exposure [Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med 2007;357:2277–84]. This is especially important in patients with chronic diseases such as inflammatory bowel disease who may require multiple studies over a lifetime or in studies that require sequential imaging time points such as in assessment of gastrointestinal motility [Froehlich JM, Patak MA, von Weymarn C, Juli CF, Zollikofer CL, Wentz KU. Small bowel motility assessment with magnetic resonance imaging. J Magn Reson Imaging 2005;21:370–75]. A recent study showed that certain subgroups of patients with Crohn's disease may be exposed to higher doses of radiation; those diagnosed at an early age, those with upper tract inflammation, penetrating disease, requirement of intravenous steroids, infliximab or multiple surgeries [Desmond AN, O’Regan K, Curran C, et al. Crohn's disease: factors associated with exposure to high levels of diagnostic radiation. Gut 2008;57:1524–29]. Therefore it has been suggested that techniques that can reduce or eliminate radiation exposure should be considered for imaging [Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med 2007;357:2277–84]. Owing to the excellent softtissue contrast, direct multiplanar imaging capabilities, new ultrafast breath-holding pulse sequences, lack of ionizing radiation and availability of a variety of oral contrast agents, MR is well suited to play a critical role in the imaging of small bowel disorders. In this article we will review the technical issues related to the performance of MR enterography and enteroclysis and discuss the role and controversies of using MR in the assessment of inflammatory bowel disease.     

MRI在老年脑疾病预警中的应用进展

我国已进入中度老龄化社会,老年脑疾病给健康带来的威胁与日俱增。以脑血管病、阿尔茨海默病、帕金森病为代表的重大脑疾病具有长期慢性发展、神经损害不可逆的特点,早发现、早干预是减轻其危害的关键策略。MRI具有无创性、多模式的优点,适于在社区人群开展大规模筛查,有望在老年脑疾病预警中发挥重要作用。结合快速成像技术、人工智能定量分析方法,可进一步提高筛查效率和准确性。概述MRI在重大脑疾病预警中的研究进展,为脑健康体检体系的建立提供思路。     

肝豆状核变性的影像学诊断

 目的了解肝豆状变性的影像学表现,明确病变范围及程度.方法采用普通X线摄片,MRI或CT对颅脑进行扫描.结果X线表现为四肢骨远端、椎体、骨盆、腕关节、指间关节等均可受累,表现形式为骨质脱钙、软化、碎裂、稀疏和骨质增生,CT表现为多发双侧对称性豆状核及周围低密度病变以及其它脑组织萎缩等表现;MRI表现为豆状核、丘脑、尾状核及齿状核在T2加权图像上呈对称异常高信号,在T1加权图像上呈低信号.结论Wilson's病在普通X线摄片、CT及MRI扫描均能检出病变,CT或MRI更能明确病变范围.     

肾上腺脑白质营养不良的临床及影像研究进展

肾上腺脑白质营养不良是一种主要累及肾上腺和脑白质的X连锁隐性遗传性代谢性疾病，以脑白质脱髓鞘和肾上腺皮质功能减退为主要临床特征。血浆、培养皮肤成纤维细胞极长链饱和脂肪酸的测定是诊断本病的主要生化指标，联合临床特征和特异性的影像学表现以及电生理检查能够帮助诊断本病，通过ABCD基因突变检测和生化检测极长链脂肪酸（very long chain fatty acid，VLCFA）可以确诊本病。本病比较少见，但进展迅速，常可导致患者神经系统不可逆的损伤直至死亡。但其确切病因发病机制尚不清楚，现就本病的病因、病理、临床表现、影像学表现及治疗等研究进展作一综述。     

胰腺疾病的MRI诊断

随着MBI成像技术的迅速发展和MBI的广泛应用，利用MBI诊断胰腺疾病正引起人们的普遍关注。现代MRI技术包括屏气T1加权成像及其脂肪抑制、T2加权成像及其脂肪抑制、MBI动态增强扫描、MR胰胆管成像和MR血管成像。这些脉冲序列各自有不同的组织对比机制，而且是互相补充的，它们的综合应用，可以较全面地评价胰腺及胰腺病变，从而明显改善了MBI对胰腺疾病的检测和诊断。本文着重介绍胰腺的MR成像技术，正常解剖、先天性异常和常见疾病的NR诊断价值。     

平山病的MRI诊断

目的：探讨平山病（hirayama disease）的MR影像学表现,提高对该病的认识。方法通过查阅相关文献,回顾性分析2例临床已确诊的平山病MR自然位和过屈位影像表现,观察其低位颈髓的动态变化,并与健康自愿者的同条件扫描影像相比较,总结平山病的MR影像学表现。结果①自然位：曲线多有异常,下段颈髓萎缩,髓内可有异常信号,有失连接现象;②过屈位：所有患者均出现颈髓前移、变扁,硬脊膜后有月牙形、集簇状异常信号影;③2例患者强化检查示过屈位脊膜后异常信号影有强化;④志愿者自然位扫描显示颈椎曲度自然,颈髓粗细均匀,不存在失连接现象,过屈位脊膜后无异常信号影。结论MR颈椎检查特别是过屈位扫描能够显示出平山病的特征性影像学改变,对于平山病的早期诊断具有重大价值。     

核素骨显像在儿科中的应用

放射性核素骨显像是诊断骨和软组织感染的选择性检查方法,不但有助于隐匿性骨折(X射线诊断阴性)的诊断,在评定小儿可疑非意外损伤方面起重要的补充作用,还可为无法解释的小儿骨痛或跛行提供诸如外伤、肿瘤、或炎症性病变的诊断依据。小儿核素骨显像要求精确的操作才能获得较清晰的诊断图像,常规全身骨显像、缩放比例、附加视图及单光子发射型计算机体层摄影术的使用等都是小儿检查的常规内容,联合CT的融合图像更进一步提高诊断的灵敏度、可信度和精确度。新的放射性药物如Na18F可能在不断更新变化的儿科骨显像技术中起重要作用。     

Steady-state free precession sequences in myocardial first-pass perfusion MR imaging: comparison with TurboFLASH imaging

The aim of this study was to compare the image quality of a saturation-recovery gradient-recalled echo (GRE; TurboFLASH) and a saturation-recovery SSFP (SR-TrueFISP) sequence for myocardial first-pass perfusion MRI. Eight patients with chronic myocardial infarction and 8 volunteers were examined with a TurboFLASH (TR 2.1 ms, TE 1 ms, FA 8°) and a SR-TrueFISP sequence (TR 2.1 ms, TE 0.9 ms, FA, 50°) on a 1.5 T scanner. During injection of 0.05 mmol/kg BW Gd-DTPA at 4 ml/s, three short axis slices (8 mm) of the left ventricle (LV) were simultaneously scanned during breath-hold. Maximum signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) between infarcted and normal myocardium, and percentage signal intensity change (PSIC) were measured within the LV lumen and in four regions of the LV myocardium for the three slices separately. For the LV lumen, SR-TrueFISP was superior in SNR and PSIC (factor 3.2 and 1.6, respectively). Mean maximum SNR, PSIC, and CNR during peak enhancement in the LV myocardium were higher for SR-TrueFISP compared with TurboFLASH (factor 2.4, 1.25, and 1.24, respectively). The SNR was higher in the septal portion of the ventricle than in anterior/posterior and lateral regions. The SR-TrueFISP provides higher SNR and improves image quality compared with TurboFLASH in first-pass myocardial perfusion MRI.     

MR扩散加权成像在甲状腺疾病诊断中的应用

目的 分析和总结MR DWI扫描试验在甲状腺良、恶性疾病中的表现特征.方法 术前经MRI常规检查和DWI检查的甲状腺占位病变患者42例,男10例,女32例.年龄20 ～72岁,平均(42±13)岁,均经手术病理证实.利用美国GE公司图像后处理软件Functool,根据不同的b值(300、500、800 s/mm2)产生ADC值,比较良、恶性病变部位的ADC值,对其进行独立样本的￡检验并绘制ROC曲线,分析试验的诊断效能.结果 42例甲状腺占位病变样本中,病理诊断为良性的28例,包括甲状腺腺瘤20例、结节性甲状腺肿6例、桥本甲状腺炎2例;恶性肿瘤14例,包括甲状腺乳头状癌11例、滤泡样甲状腺癌2例、不典型增生1例.b值为300 s/mm2时,甲状腺良性病变的ADC值为(2.39±0.38)×10-3mm2/s,恶性病变的ADC值为(1.60 +0.56)×10-3mm2/s,差异有统计学意义(t=5.35,P＜0.05).b值为500 s/mm2时,良性病变的ADC值为(1.85±0.33)×10-3mm2/s,恶性病变的ADC值为(1.65±0.42)×10-3mm2/s,差异没有统计学意义(t=1.70,P＞0.05).b值为800 s/mm2时,良性病变的ADC值为(1.61±0.30)×10.mm2/s,恶性病变的ADC值为(1.44±0.29)×10-3mm2/s,差异没有统计学意义(=1.76,P＞0.05).ROC曲线分析结果;b值为300 s/mm2时,以1.98×10-3mm2/s作为甲状腺良、恶性病变ADC值的临界值,灵敏度为85.7％,特异度为78.6％.结论 b值为300 s/mm2时,DWI图像质量好,甲状腺良性病变的ADC值明显高于恶性病变的ADC值.     

胃部影像诊断学进展

胃钡剂造影检查是胃部疾病理想的首选检查方法。运用多层螺旋CT及各种三维重建技术可全面地了解病变的形态、大小和侵犯深度。内镜超声(EUS)能判别胃壁各层组织结构，对胃恶性肿瘤侵入胃壁内的深度和邻近脏器直接浸润的判断有一定的诊断价值。随着MRI快速扫描和消除伪影序列的开发，心电门控技术的应用，胃腔内对比剂的研制，及其多方位成像和较高的密度分辨力，使它对胃部疾病的诊断能力，包括淋巴结及远处脏器转移灶的发现和鉴别能力有了进一步提高。核素扫描也开始应用于胃部肿瘤的诊断。     

MR imaging of the gastro-intestinal tract in children

MR imaging (MRI) is an established method for the evaluation of particularly inflammatory bowel disease in adults, as well as for acute abdominal pain in pregnant women. Despite the fact that MRI is ideally suited for the evaluation of children the method is still not established in these patients. The value of MRI in Crohn's disease, ulcerative colitis and appendicitis as well as intestinal tumors and malformations has been documented in children. There will be more indications in the future depending on the development of new imaging techniques, faster sequences, stronger gradients and increasing availability. Furthermore, the radiologist's attention must be drawn to decrease the radiation burden in children and to replace ionizing techniques especially in chronic disease with the need for repeated follow-up studies and in younger children. This review will discuss some general considerations for the use of MRI in evaluating the paediatric gastro-intestinal tract.     

核素心肌显像在冠心病处理决策中的合理应用及其原理

核素心肌显像在冠心病诊断、危险度分层及预后判断方面积累了大量资料,并可据此制定冠心病的有效处理策略。在ACC/AHA(美国心脏病学会/美国心脏协会)有关冠心病和核心脏病学指南中,核素心肌显像的上述作用得到了充分肯定。合理应用该技术可以提高我们对冠心病诊断处理的整体水平,并使有限的医疗资源得到更合理利用,目前这在我国显得十分迫切和必要。     

MR imaging of the skin and nipple of the breast: differentiation between tumour recurrence and post-treatment change

Contrast-enhanced MR imaging of the breast has been found to be valuable in the assessment of local recurrence of previously treated breast cancer. We looked specifically at the appearances of the skin and nipple of the treated breast in order to describe the appearances of post-treatment change and recurrence in this region. Thirty-nine women treated for breast cancer had MR imaging of one or both breasts reviewed retrospectively with particular attention to the nipple and skin. The skin and chest wall were assessed for patients with mastectomies. All available histology of the skin and/or nipple, obtained following MR imaging, was reviewed. In patients who did not undergo surgery following MR imaging, clinical follow-up was obtained. Six of 39 cases had nodular enhancing areas seen on MR imaging, which correlated with histology demonstrating tumour recurrence within the skin and/or nipple. Of the remaining 33 patients, changes of linear or diffuse enhancement were seen in the skin and/or nipple of 15 patients. These changes were shown to be benign post-treatment changes at surgery/biopsy in 4 cases or by clinical follow-up in the remainder. In this article we demonstrate differing patterns of contrast enhancement within the skin and nipple in recurrent breast carcinoma vs. post-treatment changes. This suggests that contrast-enhanced MR imaging of the breast may be a useful tool in differentiating tumour recurrence from post-treatment changes within the skin and nipple.     

Magnetic resonance imaging of avascular necrosis of the femoral head

This study investigates the role of magnetic resonance imaging (MR) in identifying avascular necrosis (AVN) of the femoral head and in monitoring its therapy. The detection of AVN, particularly in its early stages, is imperative to give therapeutic intervention the best opportunity for successful management. The results of magnetic resonance imaging are compared with those of the standard diagnostic modalities in evaluation of patients with the lesion. Examinations were performed at 0.12 T with a repetition time (TR) of 143 ms and times to echo (TE's) of 10 or 20 ms. This study represents a retrospective review of 90 hips which were examined in 45 consecutive patients. Of these, 52 hips were biopsied as part of treatment. MR was shown to be sensitive in the detection of AVN. Comparison of MR with radionuclide imaging showed comparable sensitivity and specificity. MR was also noted to be sensitive in the detection of early AVN. Preliminary results suggest that MR can monitor treatment of the affected hip, and may even be able to predict patient response to therapy. Although further work is necessary to determine the role of MR in the evaluation of the patient presenting with hip pain, MR is a sensitive method in detecting AVN and in monitoring its course in patients suspected of having the disease.     

Caroli's disease: magnetic resonance imaging features

Our objective was to describe the main aspects of MR imaging in Caroli's disease. Magnetic resonance cholangiography with a dynamic contrast-enhanced study was performed in nine patients with Caroli's disease. Bile duct abnormalities, lithiasis, dot signs, hepatic enhancement, renal abnormalities, and evidence of portal hypertension were evaluated. Three MR imaging patterns of Caroli's disease were found. In all but two patients, MR imaging findings were sufficient to confirm the diagnosis. Moreover, MR imaging provided information about the severity, location, and extent of liver involvement. This information was useful in planning the best therapeutic strategy. Magnetic resonance cholangiography with a dynamic contrast-enhanced study is a good screening tool for Caroli's disease. Direct cholangiography should be reserved for confirming doubtful cases. Electronic Publication     

静息状态下帕金森病患者脑部功能连接的MR研究

目的 探讨帕金森病患者在静息状态下脑部功能连接情况.方法 选取9例Ⅱ～Ⅲ级原发性帕金森病患者及8名年龄分布相同的健康志愿者在静息状态下进行MR扫描,选择双侧苍白球作为种子点,分析其脑部功能连接情况,并采用两样本t检验与健康对照组相比较.结果 正常健康对照组中,双侧颞极、双侧海马、双侧丘脑、扣带回后部、右侧枕中区、右侧顶上回等部位存在着功能连接.帕金森病患者的双侧小脑半球、左侧海马、双侧颞上回、后扣带同、左侧额下回、左侧额中回、左侧中央前回、左侧顶下回、左侧顶上回等部位存在功能联系,与对照纽相比,帕金森病患者的双侧小脑、双侧颞叶、左侧额叶、左侧运动前区、左侧顶叶等部位存在着功能连接增强,双侧丘脑的功能连接减弱.结论静息状态下,帕金森病脑部存在着功能连接异常现象.