Comparison of post contrast CT urography phases in bladder cancer detection.

OBJECTIVES: The aim of this study was to investigate which post-contrast phase(s) in a four-phase CT urography protocol is (are) most suitable for bladder cancer detection. METHODS: The medical records of 106 patients with visible haematuria who underwent a CT urography examination, including unenhanced, enhancement-triggered corticomedullary (CMP), nephrographic (NP) and excretory (EP) phases, were reviewed. The post-contrast phases (n = 318 different phases) were randomized into an evaluation order and blindly reviewed by two uroradiologists. RESULTS: Twenty-one patients were diagnosed with bladder cancer. Sensitivity for bladder cancer detection was 0.95 in CMP, 0.83 in NP and 0.81 in EP. Negative predictive value (NPV) was 0.99 in CMP, 0.96 in NP and 0.95 in EP. The sensitivity was higher in CMP than in both NP (p-value 0.016) and EP (p-value 0.0003). NPV was higher in CMP than in NP (p-value 0.024) and EP (p-value 0.002). CONCLUSIONS: In the CT urography protocol with enhancement-triggered scan, sensitivity and NPV were highest in the corticomedullary phase, and this phase should be used for bladder assessment. KEY POINTS: • More bladder tumours are detected during the corticomedullary phase than during other phases. • Sensitivity and NPV for bladder cancer detection were highest in corticomedullary phase. • The corticomedullary phase in CT urography should be used for bladder assessment.

Bladder cancer detection in patients with gross haematuria: Computed tomography urography with enhancement-triggered scan versus flexible cystoscopy.

OBJECTIVE: Computed tomography urography (CTU) can be used to direct further investigation of patients if the bladder tumour detection rate is high. The aim of this study was to compare a CTU protocol including an enhancement-triggered scan and flexible cystoscopy for detecting bladder tumours. MATERIALS AND METHODS: Patients with gross haematuria undergoing CTU during 2005-2008 were included. For patients younger than 50 years the CTU protocol included unenhanced, enhancement-triggered corticomedullary, and excretory phases. Patients older than 50 years followed the same protocol plus a nephrographic phase. The entire urinary tract was examined in all phases. RESULTS: Of 435 patients, 55 patients were diagnosed with bladder tumour. CTU detected bladder tumour in 48 patients (87%). Five CTU examination reports were false positive. With CTU, sensitivity for finding bladder tumour was 0.87, specificity 0.99, positive predictive value (PPV) 0.91 and negative predictive value (NPV) 0.98. Cystoscopy detected bladder tumour in 48 patients (87%) and had one false-positive finding, resulting in sensitivity of 0.87, specificity 1.0, PPV 0.98 and NPV 0.98. CONCLUSIONS: The detection rate of bladder tumours for the CTU protocol including an enhancement-triggered scan was high and comparable to flexible cystoscopy. Hence, this protocol could be used to assess the bladder as the primary investigation and direct further investigation of the patient.

Contrast enhancement in bladder tumors examined with CT urography using traditional scan phases.

BACKGROUND: Bladder assessment in an early contrast-enhancing computed tomography urography (CTU) phase requires that bladder tumors be enhanced using contrast material. PURPOSE: To investigate the enhancement pattern in bladder tumors using a CTU protocol where the scan is enhancement triggered. MATERIAL AND METHODS: Fifty patients diagnosed with bladder cancer were examined during the unenhanced (UP), corticomedullary (CMP), and excretory phases (EP). Twenty-one patients, all aged 50 years or older, were also examined during the nephrographic phase (NP). A ROI placed in the aorta was used to start the scan during the CMP when the attenuation reached 200 Hounsfield units (HU). The NP and EP were started with a 40 s and 300 s delay, respectively, after the CMP was finished. Attenuation and size measurements were made in the axial plane. RESULTS: Mean contrast enhancement of bladder tumors was 37, 25, and 17 HU in the CMP, NP, and EP, respectively. The differences in contrast enhancement were significant across all three phases. Eighty-eight percent of patients showed the highest contrast enhancement in the CMP. In 96% of the cases, contrast enhancement >20 HU was seen. The mean value of the shortest dimension of the bladder tumors was 22 ± 12 mm. CONCLUSION: The contrast enhancement is significantly higher in the CMP than in the NP and EP, suggesting that the CMP is preferable when assessing the bladder in the early contrast enhancing phase.