The Optimization And Clinical Value Of The Multi-Detecter Spiral CT And CT Urography For Upper Urinary Tract Disease

PURPOSE: To compare the effect of abdominal compression, prolonging acquisition, using oral water, prone position, intravenous frusemide, on the opacification of the normal upper urinary tract during multi-detector spiral CT urography (MDCTU). And to evaluate the value of MDCT and CT urography (MDCT and CTU) in the diagnosis of tipper urinary tract diseases.MATERIALS AND METHODS: (1) Excretory phase images were reviewed from MDCTU in 95 cases without urinary disease. Each case randomly underwent one of five imaging protocols: abdominal compression, prolonging acquisition time, using oral water, prone position, intravernous frusemide. Each side of upper urinary tract (collecting system and ureter) were divided into five pans: calices, pelvis, upper, middle and lower ureter for scoring of images on a five score scale for opacification by contrast material. Two reviewers graded scores on maximum intensity projection (MIP) images, and reviewed transverse and multiple planer reconstruction (MPR) images when necessary. Results were analysed using a one way ANOVA analysis. (2) 41 patients with urinary tract disease underwent MDCT, performed with unenhanced, contrast-enhanced, and excretory scanning. Reconstructions were performed on all patients, including MPR, MIP, and volume rendering (VR). Reviewed common CT images (unenhanced plus enhanced transverse images), delayed CT (unenhanced plus enhanced plus excretory transverse images), and all transverse CT plus CTU images. Reviewed MPR, MIP and VR images of CTU. The result of CT findings were compared with golden standards.Results: (1) The scores of intravenous injection of frusemide were highest. Frusemide and drinking water significantly improved opacification of calices and ureter, the former also had better opacification than prone and compression way. Prolonging acquisition time (eight minute) and using oral water in prone also significantly increased opacification of the whole ureter. There is no significantly difference between eight minute, using oral water in a supine and prone position. Compression tend to increased opacification, but only significant in upper ureter. Each protocol of CTU did not significantly increase opacification of the pelvis. (2) 41patients with 49 upper urinary tract lesions were proved.①For the location diagnosis of upper urinary tract diseases, sensitivities of common CT, delayed CT, and CT plus CTU images, respectively were 40/49(81.6%), 47/49(95.9%), and 48/49(98.0%); For the nature diagnosis, sensitivities respectively were 37/49(75.5%), 43/49(87.8%), and 47/49(95.9%), only the difference between common CT and CT plus CTU images was significantly (P＜0.05). For differentiation benign from maglignant lesion, the areas under the receiver operating characteristic curve (ROC) of common CT, delayed CT, CT plus CTU respectively were 0.931, 0.963 and 0.998, there is no significant difference between them. In 29 cases excretory CT images provide more information than common CT images. In 26 cases CTU images provide more information than excretory CT images.②For the location diagnosis of upper urinary tract diseases, sensitivities of MPR, MIP, and VR images, respectively were 48/4(98.0%); 27/49(53.2%), and19/49(38.8%); For the nature diagnosis, sensitivities respectively were, 47/49(95.9%), 17/49(34.7%), and13/49 (26.5%), the difference between MPR and MIP images, MPR and VR images were significantly(P<0.05). The areas under the ROC of MPR, MIP, and VR respectively were 0.998, 0.736, and 0.669, the differences between MPR and MIP images, MPR and VR images were significantly (P＜0.05).Conclusion: (1) MDCTU excretory phase images acquisition using compression only improved the opacification of upper ureter. Drinking water and prolonging acquisition time also had some help, but supine and prone position had no different opacification. Intravenous injection of small dose frusemide is the best way of all. (2) MDCT and CTU provide exact, complete, detailed and direct imaging by using excretory phase scanning and threedimensions (3-D) reconstruction, so that MDCT and CTU can exactly diagnose upper urinary tract diseases, identify maglignant from benign. It's very important for evaluation upper urinary tract disease.