The cross-sectional technique offers several advantages, such as the ability to visualize small masses, which may be obscured on excretory urography due to contrast material or bowel gas, identify focal wall thickening, and distinguish enhancing tumors from nonenhancing calculi or blood clots [5,37]. Additionally, CTU and MRU can evaluate nonfunctioning/obstructed kidneys that would not excrete the contrast medium required for excretory urography. A blinded retrospective review by Honda et al [117] of a group of 30 patients who had CTU before surgery looked at detailed criteria focusing on smooth or irregular margins to classify images into 6 patterns of T2 or lower stages and T3 or higher stages. A grading system for ureteral UCs focused on the presence of spiculation and masses along the ureter using axial nephrographic- and excretory-phase CECT images was developed. Spiculation was defined as thin strands of soft tissue extending from the tumor into the periureteric fat. The diagnostic sensitivity and specificity with respect to T3 or higher-stage tumors were 87.5% (14/16) and 92.9% (13/14), respectively. It is challenging to identify microscopic invasion of a tumor into surrounding tissue or inflammation in CT images. Other research groups have attempted to search for factors that can predict stage or prognosis for treatment decisions before surgery. In a preoperative multivariate analysis, Ito et al [118] showed that a high hydronephrosis grade predicted the pathological T stage (T3 or higher). In their study, ipsilateral hydronephrosis was graded into 5 stages, and they concluded that a higher hydronephrosis grade (2-4: mild calyceal dilatation or higher grade) predicted non- organ-confined disease. A retrospective study by Yu et al [119] looked at the correspondence of T staging on multidetector CTU and the pathologic stage of UTUC in 125 patients.
Pretreatment Staging of Urothelial Cancer. The cross-sectional technique offers several advantages, such as the ability to visualize small masses, which may be obscured on excretory urography due to contrast material or bowel gas, identify focal wall thickening, and distinguish enhancing tumors from nonenhancing calculi or blood clots [5,37]. Additionally, CTU and MRU can evaluate nonfunctioning/obstructed kidneys that would not excrete the contrast medium required for excretory urography. A blinded retrospective review by Honda et al [117] of a group of 30 patients who had CTU before surgery looked at detailed criteria focusing on smooth or irregular margins to classify images into 6 patterns of T2 or lower stages and T3 or higher stages. A grading system for ureteral UCs focused on the presence of spiculation and masses along the ureter using axial nephrographic- and excretory-phase CECT images was developed. Spiculation was defined as thin strands of soft tissue extending from the tumor into the periureteric fat. The diagnostic sensitivity and specificity with respect to T3 or higher-stage tumors were 87.5% (14/16) and 92.9% (13/14), respectively. It is challenging to identify microscopic invasion of a tumor into surrounding tissue or inflammation in CT images. Other research groups have attempted to search for factors that can predict stage or prognosis for treatment decisions before surgery. In a preoperative multivariate analysis, Ito et al [118] showed that a high hydronephrosis grade predicted the pathological T stage (T3 or higher). In their study, ipsilateral hydronephrosis was graded into 5 stages, and they concluded that a higher hydronephrosis grade (2-4: mild calyceal dilatation or higher grade) predicted non- organ-confined disease. A retrospective study by Yu et al [119] looked at the correspondence of T staging on multidetector CTU and the pathologic stage of UTUC in 125 patients.