Sensitivity of Gd-DTPA-enhanced MR imaging of benign extraaxial tumors

The effect of gadolinium diethylenetriaminepentaacetic acid (DTPA) on the sensitivity of cranial magnetic resonance (MR) imaging was measured in a prospective blinded study. Twenty-two consecutive patients with benign extraaxial tumors underwent MR imaging on a 1.5-T system without and with intravenous administration of Gd-DTPA. Readers independently interpreted the unenhanced and enhanced images without clinical information. The interpretations were compared with the anatomically verified diagnoses. Gd-DTPA improved the sensitivity of MR imaging for benign extraaxial tumors, especially in cases of residual or recurrent acoustic neuromas, multiple tumors (e.g., neurofibromatosis), or inconclusive unenhanced MR images. Enhancement with Gd-DTPA impaired the identification of a skull base tumor.     

儿童腹膜后成神经细胞瘤侵犯肾脏与肾母细胞瘤的鉴别诊断

目的评价儿童腹膜后成神经细胞瘤侵犯肾脏与肾母细胞瘤的CT表现鉴别要点。方法分析经手术证实的有明确肾脏侵犯13例腹膜后成神经细胞瘤的CT征象，并与同期经手术证实的15例肾母细胞瘤进行对照。结果13例成神经细胞瘤中12例表现为不规则肿块，11例边界不清，10例包含钙化，9例腹膜后血管受侵犯，12例有腹膜后和膈脚后淋巴结转移；15例肾母细胞瘤中，12例呈圆形肿块，2例边界不清，2例有钙化，2例腹膜后血管受侵犯，3例有腹膜后淋巴结转移；无膈脚后淋巴结转移表现。其中神经母细胞瘤的肿瘤分叶征、钙化、腹膜后和膈脚后淋巴结转移、腹主动脉和下腔静脉包埋均较肾母细胞瘤常见。其中膈脚后淋巴结转移和腹膜后血管包埋对于诊断神经母细胞瘤具有较高价值。结论膈脚后淋巴结转移和腹膜后血管包埋是成神经细胞瘤的特征性表现，对于鉴别腹膜后成神经细胞瘤与肾母细胞瘤具有重要的意义。     

特发性肺含铁血黄素沉着症的影像学表现及其与肺功能改变的相关性分析

目的分析特发性肺含铁血黄素沉着症(IPH)的影像学表现及其高分辨率CT(HRCT)表现与肺功能改变的相关性。方法回顾性分析15例IPH的影像学表现和临床资料。结果X线平片:毛玻璃样阴影9例;渗出影10例;网格状阴影7例;结节影6例。HRCT:支气管血管束改变12例;毛玻璃影12例;渗出影11例;结节影8例;小叶间隔增厚9例。HRCT上毛玻璃样阴影与肺功能的相关性分析:r=0.5394,P=0.134。HRCT上小叶间隔增厚与肺功能的相关性分析:r=0.9633,P=0.0001。结论HRCT对于病灶的显示较平片佳。小叶间隔的增厚程度与肺功能改变呈正相关,能预测肺功能的损害程度。     

新生儿和婴儿期Sturge-Weber综合征的CT诊断

目的:探讨新生儿和婴儿期Sturge-Weber综合征的CT表现。方法:回顾性分析1例新生儿期和7例婴儿期Sturge-Weber综合征患儿的临床和CT资料,均行常规CT平扫,其中5例同时行增强CT。结果:8例均有面部三叉神经分布区皮肤血管瘤,4例患儿出现患侧皮层钙化,4例未出现皮层钙化的患儿显示受累脑实质密度略增高,伴灰白质分界不清。8例患儿均表现为局部脑外间隙增宽及脑沟增宽等脑萎缩样改变,3例随访患儿出现脑萎缩。5例行增强扫描的患儿出现脑回样强化,4例患侧的侧脑室脉络丛增大,1例双侧Sturge-Weber综合征于10个月随访时出现双侧脉络丛增大。结论:CT对新生儿和婴儿期Sturge-Weber综合征的诊断有重要价值。     

Cerebellopontine angle-petromastoid mass lesions: comparative study of diagnosis with MR imaging and CT

Capabilities of computed tomography (CT) and magnetic resonance (MR) imaging in the diagnosis of cerebellopontine angle-petromastoid (CPA-PM) lesions were compared in 75 patients. CT and MR demonstrated 95.8% and 98.7% of the lesions, respectively. MR was often more helpful for characterization of neuromas, epidermoid cysts, exophytic gliomas, and vascular lesions, while CT was usually more informative for meningiomas, metastases, and tympanomastoid cholesteatomas. A specific diagnosis could be made with MR for most types of lesions through use of relaxation parameters and characteristic morphologic changes. Size, shape, location, and contour of the lesions, however, were generally more helpful for differential diagnosis than relaxation times. With the exception of metastatic lesions, cholesteatomas, and some meningiomas, MR was usually more helpful than CT in defining the full extent of the lesions and their relationships to contiguous structures. MR, because of its high accuracy in lesion detection, characterization, and localization, is a suitable primary diagnostic modality for evaluating patients with suspected CPA-PM lesions.     

Influence of the endothelium on Ca2+ dependency of angiotensin II-induced contractions of rat aortic rings

Summary— Endothelium-dependent relaxation has been demonstrated to be involved in the regulation of vascular tone and extracellular Ca²⁺ was found to play a prominent role in this process. Since the dependency on extracellular Ca²⁺ appeared to differ considerably within the arterial tree, possibly as a consequence of vessel-related endothelium-dependent mechanisms, we investigated the effects of different compounds affecting Ca²⁺ entry (nifedipine, CoCl₂) on angiotensin II-induced contractions of rat aortic rings with and without endothelium as well as the responses in a Ca²⁺–“free” solution. For this purpose, rat aortic rings were either undone from their endothelial layer by gentle mechanical rubbing or care was taken to keep the intima intact in case rings where endothelium were required. The presence of an intact endothelium was confirmed by acetylcholine-induced relaxation. A stronger responsiveness towards angiotensin I, both after a complete concentration-response curve and after a single maximal concentration of angiotensin II was observed in arterial segments without endothelium. The maximal contraction to a single concentration of angiotensin II (0.1 μM) in the rings without endothelium amounted to 75.8 ± 3.8% of the preceding response to a supramaximal concentration of noradrenaline (= E_max). In rings without the endothelial layer, the contraction was 34.8 ± 3.7% of E_max. This indicates an endothelium-induced relaxation in aortic rings with endothelium. After incubation with the Ca²⁺ entry blocker nifedipine (1 μM) both rings with and without endothelium were inhibited to the same extent, contractions amounted to 30.7 ± 1.8% and 19.6 ± 1.3% of E_max, respectively. However, incubation in a Ca²⁺-“free” medium for 5 min resulted in similar contractions for rings without endothelium (16.4 ± 1.4% of E_max) as for rings with endothelium (15.0 ± 1.6% of E_max). Moreover, CoCl₂ in a concentration of 300 μM hardly inhibited the contraction of rings with an intact endothelium, a contractile response of 30.5 ± 2.8% of E_max was observed. The results of the study suggest that the influx of Ca²⁺ions is indeed responsible for the endothelium-mediated relaxation. However, this influx, which cannot be antagonized by nifedipine, but has shown to be affected by CoCl₂, suggests that channels intensitive to organic Ca²⁺ entry blockers may be involved.