Nolte-Ernsting C C, Krombach G, Staatz G, Kilbinger M, Adam G B, Günther R W
Klinik für Radiologische Diagnostik, Universitätsklinikum der RWTH Aachen.
Rofo. 1999 Jun;170(6):550-6. doi: 10.1055/s-2007-1011090.
To investigate the feasibility of reconstructing a virtual endoscopy from MR imaging data sets of the upper urinary tract.
The data obtained from 28 contrast-enhanced MR urographic examinations (5 normal; 23 pathologic) were post-processed to reconstruct a virtual ureterorenoscopy (VURS) using a threshold image segmentation. The visualization of the upper urinary tract was based on the acquisition of T1-weighted 3D gradient-echo sequences after intravenous administration of gadolinium-DTPA and a prior injection of low-dose furosemide.
The employed MR urography technique created in all 28 cases a complete and strong contrast enhancement of the urinary tract. These 3D sequence data allowed the reconstruction of a VURS, even when the collecting system was not dilated. The best accuracy was provided by the MR urography sequences with the smallest voxel size. Moreover, the data acquisition based on a breath-hold technique has proved superior to that using a respiratory gating. Inside the renal pelvis, all calices could be assessed by turning the virtual endoscope in the appropriate direction. The visualization of the ureteral orifices in the bladder was also possible. All filling defects that were diagnosed by MR urography could be evaluated from the endoluminal view using the VURS. The exact characterization of the lesions based only on the assessment of the surface structure was difficult.
A virtual endoscopy of the upper urinary tract can be successfully reconstructed using the data sets of high-resolution 3D MR urography sequences.
探讨从上尿路的磁共振成像数据集重建虚拟内窥镜的可行性。
对28例对比增强磁共振尿路造影检查（5例正常；23例病理）获得的数据进行后处理，采用阈值图像分割重建虚拟输尿管肾镜（VURS）。上尿路的可视化基于静脉注射钆喷酸葡胺后并预先注射低剂量速尿后采集的T1加权三维梯度回波序列。
所采用的磁共振尿路造影技术在所有28例病例中均使尿路产生了完整且强烈的对比增强。即使集合系统未扩张，这些三维序列数据也能重建VURS。体素尺寸最小的磁共振尿路造影序列提供了最佳的准确性。此外，基于屏气技术的数据采集已证明优于使用呼吸门控的采集。在肾盂内，通过将虚拟内窥镜转向适当方向可以评估所有肾盏。膀胱内输尿管口的可视化也是可能的。磁共振尿路造影诊断出的所有充盈缺损都可以使用VURS从腔内视图进行评估。仅基于表面结构评估来准确表征病变很困难。
使用高分辨率三维磁共振尿路造影序列的数据集可以成功重建上尿路的虚拟内窥镜。
