Hiroshi Juri, Presenter: Nothing to Disclose

Takahiro Tsuboyama MD, Abstract Co-Author: Nothing to Disclose

Seishi Kumano MD, Abstract Co-Author: Nothing to Disclose

Kazuhiro Yamamoto MD, Abstract Co-Author: Nothing to Disclose

Haruhito Azuma, Abstract Co-Author: Nothing to Disclose

Yoshifumi Narumi MD, Abstract Co-Author: Nothing to Disclose

To prospectively compare the diagnostic ability of low dose scans with adaptive iterative dose reduction 3D (AIDR 3D) and routine dose scans with filterd back projection (FBP) for the detection of bladder cancer on the excretory phase (EP) in CT urography. 

Forty-two patients known to have or at high risk for urothelial carcinoma were included. Routine and low dose EP of CT urography were performed at 15 minutes after administration of contrast material. Low dose images were reconstructed with AIDR 3D and routine dose images were reconstructed with FBP. Two radiologists independently scored the confidence levels for the presence or absence of bladder cancer using 5-point scale, and the number of tumors in the urinary bladder was recorded on each EP. Differences were resolved by consensus. Standard of reference was obtained from histopathologic findings or cystoscopy. In addition, one radiologist measured the maximum diameter of the tumor of each patient, and averaged. The CT dose index (CTDIvol) was measured and the percentage of dose reduction was calculated.

Bladder cancer was revealed in 23 patients by cystoscopy. The mean maximum diameter of the tumors of each patient was 32.8 mm (range; 5.7 - 101.3 mm). Sensitivity, specificity, and accuracy were 87.0%, 94.5%, and 90.5% on routine dose, and were 87.0%, 89.5%, and 88.1% on low dose scans, respectively, and there was no significant difference. Area under the receiver perating characteristic curves for detecting cancer was 0.915 and 0.901 on routine and low dose scans, and there was no significant difference (p = 0.263). The number of tumors in the urinary bladder on low dose scans was almost equal to that on routine dose scans in all patients with bladder cancer. The average CTDIvol was 8.07 mGy and 2.61 mGy on routine and low dose scans, and the percentage of the dose reduiction with low dose scans was 67.8%.

The d scansiagnostic ability of low dose scans with AIDR 3D is almost equal to that of routine dose scans with FBP on the EP in CT urography. The dose reduction is nearly 70% using AIDR 3D.

Using AIDR 3D, we can perform nearby 70% dose reduction without worsening the diagnostic ability for the detection of bladder cancer on the excretory phase in CT urography.

Juri, H, Tsuboyama, T, Kumano, S, Yamamoto, K, Azuma, H, Narumi, Y, Detection of Bladder Cancer: Comparison of Low Dose Scans Using Adaptive Iterative Dose Reduction 3D and Routine Dose Scans Using Filterd Back Projection in CT Urography.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045484.html