Split-bolus CT urography after microwave ablation of renal cell carcinoma improves image quality and reduces radiation exposure

• Published in: Abdominal imaging Vol. 47; no. 6; pp. 2230 - 2237
• Main Authors: Tannenbaum, Alex P., Lubner, Meghan G., Mithqal, Ayman, Ziemlewicz, Timothy J., Allen, Glenn O., Brace, Christopher L., Jason Abel, E., Mankowski-Gettle, Lori, Schenkman, Noah S., Wells, Shane A.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.06.2022; Springer Nature B.V
• Subjects: Ablation; Continuity (mathematics); Gastroenterology; Hepatology; Image quality; Imaging; Interventional Radiology; Kidney cancer; Medical imaging; Medicine; Medicine & Public Health; Microwave ablation; Pelvis; Qualitative analysis; Quality assessment; Radiation; Radiation dosage; Radiation effects; Radiology; Renal cell carcinoma; Tumors; Urography; Microwave; CT; Renal cell carcinoma; Iodinated contrast; Ablation
• ISSN: 2366-0058; 2366-004X; 2366-0058
• DOI: 10.1007/s00261-022-03448-x

Objective To compare image quality and radiation dose between single-bolus 2-phase and split-bolus 1-phase CT Urography (CTU) performed immediately after microwave ablation (MWA) of clinically localized T1 (cT1) RCC. Methods Forty-two consecutive patients (30 M, mean age 67.5 ± 9.0) with cT1 RCC were treated with MWA from 7/2013 to 12/2013 at two academic quaternary-care institutions. Renal parenchymal enhancement, collecting system opacification and distention and size-specific dose estimate (SSDE) were quantified and image quality subjectively assessed on single-bolus 2-phase versus split-bolus 1-phase CTU. Kruskal–Wallis and Pearson’s Chi-squared tests were performed to assess differences in continuous and categorical variables, respectively. Two-sample T test with equal variances was used to determine differences in quantitative and qualitative image data. Results Median tumor diameter was larger [2.9 cm (IQR 1.7–5.3) vs 3.6 cm (IQR 1.7–5.7), p  = 0.01] in the split-bolus cohort. Mean abdominal girth ( p  = 0.20) was similar. Number of antennas used and unenhanced CTs obtained before and during MWA were similar ( p  = 0.11–0.32). Renal pelvis opacification (2.5 vs 3.5, p  < 0.001) and distention (4 mm vs 8 mm, p  < 0.001) were improved and renal enhancement (Right: 127 HU vs 177 HU, p  = 0.001; Left: 124 HU vs 185 HU, p  < 0.001) was higher for the split-bolus CTU. Image quality was superior for split-bolus CTU (3.2 vs 4.0, p  = 0.004). Mean SSDE for the split-bolus CTU was significantly lower [163.9 mGy (SD ± 73.9) vs 36.3 mGy (SD ± 7.7), p  < 0.001]. Conclusion Split-bolus CTU immediately after MWA of cT1 RCC offers higher image quality, improved opacification/distention of the collecting system and renal parenchymal enhancement at a lower radiation dose.