抑脂技术和动态增强MRI在胰岛素瘤诊断中的价值探讨

目的 探讨抑脂技术和动态增强MRI在胰岛素瘤术前定位诊断中的价值。方法 12例手术病理证实的胰岛素瘤患者术前行MR检查，扫描序列包括：横断面SE T1WI，快速自旋回波(FSE)T2WI，加脂肪抑制技术的T1WI和T2WI(即T1WI FS和T2WI FS)，快速多层面扰相梯度回波(FMPSPGR)序列作动态增强扫描。结果 在常规T1WI和T2WI序列仅检出4例肿瘤，表现为T1WI稍低信号和T2WI稍高信号。在T1WI FS上7例呈均匀低信号，显示清晰；在T2WI FS上6例病灶呈不同程度的高信号。快速动态增强扫描(FMPSPGR)检出11例肿瘤，在动脉期7例肿瘤明显强化呈高信号，4例轻度强化呈稍高信号，1例无明显强化呈等信号，胰腺实质期和门脉期6例仍呈高信号，6例呈等信号。与手术后病理结果比较，动态增强MRI对胰岛素瘤术前定位诊断准确率为91．7％(11／12)。结论 动态增强MRI是胰岛素瘤术前定位诊断敏感而准确的方法。     

MRI appearance of primary giant ovarian leiomyoma in a hysterectomised woman

Primary leiomyoma is a rare, benign tumour of the ovary. We describe the MRI features of an ovarian leiomyoma identified in a 51-year-old woman after hysterectomy. The tumour appeared as a well-circumscribed low signal intensity mass on T(1) weighted imaging, with mixed signal intensity on T2 weighted imaging. Areas of high signal intensity on T2 weighted imaging corresponded to degeneration of leiomyoma. Dynamic contrast-enhanced imaging revealed early enhancement of the lesion. MRI appearance was thus similar to that of uterine leiomyoma. This case suggests the potential usefulness of dynamic contrast-enhanced MRI for the diagnosis of ovarian leiomyoma.     

Combined MR examination of prostate: is it reliable?

A combination of magnetic resonance (MR) methods (T2-weighted MRI, proton MR spectroscopy, and dynamic contrast enhancement) gives the highest sensitivity and specificity for identification of prostate cancer by MRI. The prostate MR findings of a patient with a congenital cystic disease of seminal vesicle are presented. To our knowledge, this is the only case described in the literature. The MR examination resulted in a false-positive indication of prostate cancer.     

Detection of hepatocellular carcinoma: combined T2-weighted and dynamic gadolinium-enhanced MRI versus combined CT during arterial portography and CT hepatic arteriography

PURPOSE: The purpose of this study was to compare the preoperative detectability of hepatocellular carcinomas (HCCs) using combined T2-weighted and dynamic gadolinium-enhanced MRI and combined CT during arterial portography (CTAP) and CT hepatic arteriography (CTHA). METHOD: Thirty-three patients with 43 HCCs underwent T2-weighted and dynamic gadolinium-enhanced MRI and combined CTAP and CTHA. The diagnosis was established by pathologic examination following surgical resection in 26 patients and by biopsy in 7 patients. The MR protocol included fast SE with two TEs (including T2-weighted imaging) and precontrast and gadolinium-enhanced T1-weighted fast multiplanar spoiled gradient-recalled echo images with dynamic study. The MR images of all sequences and the paired CTAP and CTHA images were independently reviewed by three radiologists. Image review was conducted on a segment-by-segment basis. Diagnostic accuracy was evaluated with receiver operating characteristic analysis. RESULTS: The accuracies (Az values) of MRI of all sequences and combined CTAP and CTHA for all observers were 0.960 and 0.959, respectively. The mean sensitivities of MRI and CT were 90 and 94%, respectively. The differences were not statistically significant. The mean specificity of MRI (99%) was significantly higher than that of combined CTAP and CTHA (92%). CONCLUSION: Combined T2-weighted and dynamic gadolinium-enhanced MRI is as accurate as combined CTAP and CTHA for preoperative detection of HCCs.     

Gd-BOPTA增强MRI对小肝癌的诊断价值

目的　比较Gd BOPTA增强MRI与MRI平扫、Gd DTPA动态增强MRI在诊断小肝癌 (SHCC)方面的差异 ,进一步提高小肝癌检出率和诊断准确性并观察其不良反应。资料与方法　手术或穿刺病理证实为SHCC患者 2 5例。采用GESigna 1.5T磁共振扫描仪。行SE序列T1WI、FSE序列T2 WI及Gd DTPA快速动态增强多期扫描。Gd BOPTA增强扫描亦采用静脉团注快速动态增强扫描 (同Gd DTPA) ,并在团注后 15min、6 0min行SE序列T1WI和FMPSPGR序列T1WI扫描各 1次。观察MRI平扫、Gd DTPA快速动态增强和Gd BOPTA增强扫描及延迟扫描对病灶的检出率、包膜显示情况以及病灶的强化特征并行统计学分析。观察其不良反应。结果　 2 5例患者共发现病灶4 2个。对SHCC病灶的检出率 ,MRI平扫为 6 9.0 5 % ,Gd DTPA增强为 85 .71% ,Gd BOPTA增强 (动态 延迟 )为95 .2 4 % ,和Gd DTPA增强之间无统计学差异 ,和MRI平扫有统计学意义。病理检查发现 30个病灶有包膜。Gd BOPTA增强对SHCC包膜的显示 ...     

广州管圆线虫病中枢神经系统受侵的磁共振影像研究

目的：研究中枢神经系统广州管圆线虫病的磁共振影像表现。方法：５例经实验室检查和临床治疗证实的广州管圆线虫病患者共做头部及颈腰部ＭＲＩ检查１７例次。ＭＲＩ扫描仪为０．５Ｔ超导装置。在ＭＲＩ不同序列上观察脑、脊髓、脑脊膜和神经根有无病变及其分布、形态及信号表现,通过随访ＭＲＩ检查,分析病变出现及消散、好转情况。结果：５例患者ＭＲＩ显示脑膜脑炎３例,脑炎１例,脊髓脊膜炎１例。具体病变部位及表现如下：（１）脑实质累４例,脊髓１例。这些病变呈弥漫或散在分布,在Ｔ１ＷＩ上呈稍低或等信号,在Ｔ２ＷＩ和对应层面液体衰减反转恢复序列（ＦＬＡＩＲ）图像上呈高信号,注射钆喷替酸葡甲铵（Gd-DTPA）后病变中央可见圆形或卵圆形强化灶,最大直径１０mm。有时可见粗细不等的长条形强化,长达１４mm。强化灶周围可有小范围的低信号水肿区。（２）脑脊膜受累４例,其中包括室管膜及神经根受累各１例。注射Gd-DTPA后表现为软脑膜或（和）室管膜呈线条形或结节状强化及神经根强化。（３）轻度脑室扩张２例。追踪动态观察提示,发病后第５～８周是颅内病变最明显的时期,病变从发现至消退至少需要８周时间。结论：中枢神经系统广州管圆线虫病的ＭＲＩ表现多种多样。脑脊髓内多发长条形或结节状强化和软脑膜强化是本病主要的ＭＲＩ表现。     

原发输尿管癌的MRI诊断并与其他影像诊断方法的比较

目的 探讨原发输尿管癌的MR检查方法、影像表现并与其他影像方法比较，评价其临床价值。方法 搜集近8年来手术治疗的原发输尿管癌87例，其中35例行MR检查。使用GE1．5 T MR机，所有病例先行冠状面重T2WI水成像以显示输尿管积水，如有梗阻则在梗阻水平行T2WI和T1WI扫描，其中11例进一步做了动态增强扫描。以手术所见和病理诊断为参照，对术前各种影像诊断的原始报告进行比较分析。结果 35例中MRI显示33例患侧输尿管有不同程度积水，1例无异常发现，1例仅显示肾移植术后原肾萎缩改变。横轴面扫描33例有输尿管积水者中的32例在梗阻水平显示有异常软组织占位信号。增强扫描病灶呈逐渐、均匀的轻度或中等异常对比强化。同时期输尿管癌患者术前影像检查使用率依次为：B超(94．3％)、静脉肾盂造影(IVU，59．8％)，CT(52．9％)，MRI(40．2％)和逆行输尿管造影(RUP，35．6％)。诊断准确率依次为：MRI(91．4％)，RUP(80．6％)，CT(63．O％)，B超(47．6％)和IVU(11．5％)。结论 MR水成像与传统序列结合使用能清晰显示绝大多数有输尿管梗阻的原发输尿管癌病变，在常用的影像检查手段中诊断准确率最高，在B超筛查的基础上应作为首选。     

Prostate cancer screening: the clinical value of diffusion-weighted imaging and dynamic MR imaging in combination with T2-weighted imaging

PURPOSE: To evaluate the clinical value of diffusion-weighted imaging (DWI) and dynamic MRI in combination with T2-weighted imaging (T2W) for the detection of prostate cancer. MATERIALS AND METHODS: A total of 83 patients with elevated serum prostate specific antigen (PSA) levels (>4.0 ng/mL) were evaluated by T2W, DWI, and dynamic MRI at 1.5 T prior to needle biopsy. The data from the results of the T2W alone (protocol A), combination of T2W and DWI (protocol B), and the combination of T2W+DWI and dynamic MRI (protocol C) were entered into a receiver operating characteristic (ROC) curve analysis, under results of systemic biopsy as the standard of reference. RESULTS: Prostate cancer was pathologically detected in 44 of the 83 patients. The sensitivity, specificity, accuracy, and the area under the ROC curve (Az) for the detection of prostate cancer were as follows: 73%, 54%, 64%, and 0.711, respectively, in protocol A; 84%, 85%, 84%, and 0.905, respectively, in protocol B; and 95%, 74%, 86%, and 0.966, respectively, in protocol C. The sensitivity, specificity, and accuracy were significantly different between the three protocols (P < 0.01). CONCLUSION: In patients with elevated serum PSA levels, the combination of T2W, DWI, and dynamic MRI may be a valuable tool for detecting prostate cancer and avoiding an unnecessary biopsy without missing prostate cancer.     

Assessment of ameloblastomas using MRI and dynamic contrast-enhanced MRI

We retrospectively evaluated magnetic resonance images (MRI) and dynamic contrast-enhanced MRI (DCE-MRI) of ameloblastomas. MRI and DCE-MRI were performed for 10 ameloblastomas. We obtained the following results from the MRI and DCE-MRI. (a) Ameloblastomas can be divided into solid and cystic portions on the basis of MR signal intensities. (b) Ameloblastomas show a predilection for intermediate signal intensity on T1WI, high signal intensity on T2WI, and well enhancement in the solid portion; they also show a homogeneous intermediate signal intensity on T1WI and homogeneous high signal intensity on T2WI, and no enhancement in the cystic portion. (c) The mural nodule or thick wall can be detected in ameloblastomas lesions. (d) CI curves of ameloblastomas show two patterns: the first pattern increases, reaches a plateau at 100-300 s, then sustains the plateau or decreases gradually to 600-900 s, while the other increases relatively rapidly, reaches a plateau at 90-120 s, then decreases relatively rapidly to 300 s, and decreases gradually thereafter. There was no difference in the CI curve patterns among primary and recurrent cases, a case with glandular odontogenic tumor in ameloblastoma or among histopathological types such as plexiform, follicular, mixed, desmoplastic, and unicystic type.     

CT and MRI findings of carcinoma showing thymus-like differentiation

Carcinoma showing thymus-like differentiation (CASTLE) is a rare tumor that occurs in the soft tissue of the neck or in the thyroid gland. We report a case of CASTLE in a 54-year-old man presenting with hoarseness. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a mass enclosing the right carotid artery with the shape of lobulation and invasion to the trachea. The mass was hypointense on T1-weighted imaging and, on T2-weighted imaging, showed a hyperintense periphery with isointense center relative to muscle. In dynamic MRI, the mass revealed gradual but slight heterogeneous enhancement from the periphery. Diagnosis was confirmed by histopathology.     

获得性胸主动脉病变的MRI诊断

目的：评价ＭＲＩ对获得性胸主动脉病变的诊断价值。材料和方法：共３０例,２１例在ＧＥＶｅｃｔｒａ０．５Ｔ上行ＳＥ和ＣｉｎｅＭＲＩ检查,９例在ＧＥＳｉｇｎａ１．５Ｔ上行ＳＥ、ＣｉｎｅＭＲＩ、ＧａｔｅｄＴＯＦ和３Ｄ动态增强ＭＲＡ检查。成像采用横断面、主动脉长轴和左室长轴观,部分加扫矢状面和冠状面。结果：共发现升主动脉瘤１０例、主动脉夹层１０例、主动脉扩张９例和降主动脉溃疡１例。经对照表明ＣｉｎｅＭＲＩ对合并的瓣膜病变、夹层真假腔、血栓和瘤内异常血流方式的显示较ＳＥ为佳,而ＧａｔｅｄＴＯＦ和３Ｄ动态增强ＭＲＡ对整个胸主动脉形态及头臂血管的显示最佳。结论：多种ＭＲＩ技术综合运用诊断获得性胸主动脉病变可基本达到心血管造影效果。     

Dynamic MR imaging of liver lesions with superparamagnetic iron oxide (SH-U-555A)

Dynamic MRI with SH-U-555 (SPIO) was evaluated. Dynamic MRI was performed for 17 patients with 22 lesions. Dynamic study with T2*-weighted imaging (T2* dynamic) and T1-weighted imaging (T1 dynamic) were performed in 8 cases (10 lesions) and 9 cases (12 lesions), respectively. T2* dynamic MR images were obtained before and 30, 90, 180, 270, 360, and 450 seconds and 31 minutes after the intravenous injection of SPIO, and T1 dynamic MR images were obtained before and 0, 40, 80, 120, 180, 240, 300, 360, 420, and 480 seconds and 28 minutes after the injection of SPIO. The signal intensity of each lesion was measured before and after the injection of SPIO. The enhancement ratio of the lesions was calculated and evaluated. The enhancement ratio of hypervascular lesions decreased rapidly in the first phase of T2* dynamic MRI, while that of hypovascular lesions decreased gradually. The enhancement ratio of hypervascular lesions increased in the first phase of T1 dynamic MRI and decreased gradually, while that of hypovascular lesions lacked the increase in the first phase, in contrast to hypervascular lesions. However, the changing of signal intensity could not be recognized on images with T2* dynamic and T1 dynamic study. In conclusion, quantitative analysis using the enhancement ratio made it possible to anticipate lesion vascularity.     

Computed tomographic and magnetic resonance features of inflammatory myofibroblastic tumor of the lung in children

We report two cases of inflammatory myofibroblastic tumor (IMT) of the lung in a 4-year-old boy and a 7-year-old girl. We performed dynamic contrastenhancement computed tomography in both of our cases and dynamic contrast enhancement magnetic resonance imaging (MRI) in one case. These dynamic studies showed a demarcated mass with delayed enhancement in both cases. A T1-weighted MR image shows a mass with homogeneous low signal intensity, and a T2- weighted image shows a mass with slightly high signal intensity. A post-contrast-enhanced T1-weighted image demonstrates homogeneous enhancement. We speculate that the delayed enhancement could be attributed to the abundant fibrous tissue, which was the main structural material of the tumor. This same finding has been described in previous reports of IMT in other organs.     

MR imaging in the assessment of a solitary bone cyst

Introduction: It might be difficult to differentiate solitary bone cysts (SBCs) from other cysts and tumors when the lesion occurs at an unusual location and/or shows atypical radiographic features. Magnetic resonance imaging (MRI) is the most useful modality for evaluating the internal structure of lesions and may have the ability to distinguish SBCs from other lesions. However, few studies exist regarding MRI of SBCs in the oral region. The present study reports on the MR imaging of nine patients with SBCs and describes the diagnostic value of the MRI findings. Materials and methods: Nine patients with SBCs in the mandible were examined using MRI. In all patients, T1- and T2-weighted images (T1-WI, T2-WI) were obtained and contrast enhanced images and dynamic MRI were performed in four cases. Results: MR findings revealed homogeneous intermediate signal intensities (SI) on T1-WI and high SI on T2-WI in all cases. These SI indicated that the SBCs included homogeneous liquid. On the dynamic MRIs in all cases, the SBCs were enhanced from the margin to the inner part, indicating a gradual exudation of the contrast agent from the surrounding medullae to the inner part. These phenomena were not observed on the dynamic MRIs of the other true cysts with epithelial lining. Conclusion: MRI, especially dynamic MRI, can provide useful information for distinguishing SBCs from other cysts or tumors. Furthermore, dynamic MRI findings suggested that the liquid components of SBCs might have infiltrated from the surrounding medullae.     

MRI动态增强扫描在肝脏炎性假瘤诊断与鉴别中的价值

目的探讨MRI平扫及动态增强在肝脏炎性假瘤(IPL)诊断与鉴别中的价值。资料与方法回顾性分析行Gd-DTPA动态增强MRI检查并经手术病理证实的IPL12例13个病灶,重点观察病灶在动态增强扫描中的强化方式及特点。结果12例患者共发现13个病灶,在T1WI上,4个病灶呈等信号,其余呈低信号。在T2WI上,6个病灶呈高信号,4个呈等信号,3个呈低信号。动态增强扫描后,病灶强化方式及特点如下:(1)全部病灶呈延迟强化;(2)动脉期4个病灶可见强化,其余无明显强化;(3)门静脉期和延迟期可见周边部环形强化(9/13,69.23%)、分隔样强化(6/13,46.15%)、中心或偏心性小结节状强化(2/13,15.38%)、全瘤不均质强化(1/13,7.69%);(4)延迟期病灶内存在无强化区(7/13,53.85%);(5)延迟期病灶缩小感(4/13,30.77%)。结论MRI动态增强扫描可反映IPL的血供特点及病理特征,对定性诊断与鉴别有较高的临床价值。     

3.0TMRI高b值扩散加权成像在宫颈癌分期中的应用

目的：探讨3.0T MRI 扩散加权成像(DWI)单一序列在宫颈癌诊断及分期中的应用价值。方法2名观察者分别独立分析65例宫颈癌患者术前 T2 WI、DWI 和 LAVA-Flex 动态增强图像,比较三者对宫颈癌影像学分期结果的差异,对肿瘤的 T2 WI、DWI 和 LAVA-Flex 动态增强图像进行分期效能评估。结果DWI 检测到所有的病灶,其中3例病灶在常规 T2 WI 序列未能发现,1例在动态增强图像上未能发现。DWI、T2 WI 与 LAVA-Flex 动态增强对宫颈癌总体分期准确率分别为90.8%、78.5%、87.7%。DWI 单一序列分期的准确率高于单一 T2 WI 序列(P =0.04),DWI 序列与多期动态增强序列分期准确率无显著差异(P =0.39)。结论单一的 DWI 序列在宫颈癌分期中的准确性优于单一的 T2 WI 序列,在不具备增强的条件下 DWI 有望替代 MRI 动态增强序列,对宫颈癌做出准确的分期。     

胰岛素瘤的MRI诊断

目的：探讨胰岛素瘤的MRI表现及最佳检查序列。资料与方法：分析经手术、病理证实6例胰岛素瘤的MRI表现，检查序列包括SE T1WI、FSE T2WI、预饱和脂肪抑制T1WI，常规增强和动态增强检查。其中4例行CT平扫和双期增强检查。比较增强前后MRI不同序列胰岛素瘤的检出率，并与CT检查进行对照。结果：MRI检出了所有6例胰岛素瘤，其中预饱和脂肪抑制T1WI的检出率最高（6／6），其次是常规SE T1WI（5／6），而FSE T2WI（2／6）、常规增强T1WI（2／5）和动态增强检查（2／3）的显示率较低，但增强检查尤其是动态增强检查有助于显示肿瘤的富血供特征。CT对胰岛素瘤的检出率（平扫1／4，双期增强2／3）要低于MRI。结论：对于胰岛素瘤，MRI是一种较佳无创性检查方法，能够检出双期增强CT检查漏诊的肿瘤。MR预饱和脂肪抑制T1WI是最佳检查序列，增强尤其是动态增强则能反映肿瘤的富血供特征。     

乳腺恶性肿瘤磁共振征象分析

目的 探讨乳腺恶性肿瘤的MRI平扫及动态增强扫描白影像特点。材料与方法 27例乳腺恶性肿瘤行MRI平扫,其中12例行动态增强扫描,结合手术病理结果,分析乳腺恶性肿瘤的形态、信号、强化特点以及与病理类型的关系。结果 27例患者中平扫15例具有不规则形态、T2WI不均匀高信号、周边有毛刺等典型恶性征象,余12例需行动态增强扫描者,7例呈“快进快出”方式强化。浸润性小叶癌T2WI信号较低,强化不明显,呈不典型表现;粘液腺癌及叶状囊肉瘤肿块较大,周边毛刺不明显,强化呈“快进慢出”方式,表现亦不典型。结论 MRI平扫结合动态增强扫描是诊断乳腺恶性肿瘤的有效方法。     

Bright-dark ring sign in MR imaging of hepatic epithelioid hemangioendothelioma

We describe the imaging findings in a rare case of multifocal nodular form of hepatic epithelioid hemangioendothelioma on ultrasound (US) and dynamic contrast-enhanced spiral computed tomography (CT) and MRI. The nodules showed multilayered target appearance on MR images with prominent peripheral rim with high signal intensity (SI) on T1-weighted and very low SI on T2-weighted images, corresponding to thrombosed vascular channels. The above combination of imaging findings is to our knowledge distinct and should suggest the diagnosis of hepatic epithelioid hemangioendothelioma.     

Dynamic contrast-enhanced MRI in normal and abnormal prostate tissues as defined by biopsy, MRI, and 3D MRSI.

This study characterized dynamic contrast-enhanced (DCE) MRI of prostate tissues: cancerous peripheral zone (PZ), normal PZ, stromal benign prostatic hyperplasia (BPH), and glandular BPH. MRI, MRSI, and DCE MRI were performed on 25 patients. Tissues were identified with MRI, MRSI, and (when available) biopsy results. Motion between MRI and DCE MRI, and within DCE MRI was assessed and manually corrected. To assess tissue and patient effects, native T1's were measured in 12 of 25 patients, and DCE MRI results were normalized to muscle enhancement. Regions of cancer had a higher peak enhancement (P < 0.006), faster enhancement rate (P < 0.0008), and faster washout slope (P < 0.05) than normal PZ tissues. Stromal BPH had the fastest enhancement rate (P < 0.003) of all tissues and tended to have the greatest enhancement. Intersequence motion averaged 2.6 mm and reached 7.9 mm. Motion within DCE MRI was generally minimal (<2 pixels), but one case showed a large shift that would have confounded the results. Native T1's were similar across the prostatic tissues. Interpatient variability in DCE MRI was only partially reduced by normalization to muscle. DCE MRI of the prostate discriminated PZ cancer from normal PZ tissues and predominantly stromal and glandular BPH.