We read with great interest the comments from Dr. Masahiro Jinzaki and his colleague regarding our article [1], and we appreciate their interest in our recent work. We are pleased that they share the same idea with us that contrast-enhanced CT may reveal tumor microvascular heterogeneity among individual tumors. However, there were some differences between the Jinzaki et al. study [2] and our study. In their study, the homogeneity of enhancement was defined when more than 90% of the area was occupied by the same attenuation value ascertained by visual inspection, and pathologic findings revealed any renal cell carcinoma (RCC) with heterogeneity of enhancement that showed intratumoral necrosis or hemorrhage on the histologic specimen.
Clearly, necrotic areas must not provide microvasculature. So the heterogeneity of tumor in the Jinzaki et al. study [2] referred to tumor with and without microvascularity. In our study, we selected two regions of interest (ROIs) on fairly heterogeneously enhanced parenchyma of tumor, avoiding cystoid change and intratumoral necrosis because parenchyma of tumor can reflect the characteristics of tumor. Therefore, we evaluated the heterogeneity of only tumor with microvasculature. We fully agree with Dr. Jinzaki and his colleague that multiphase scanning of the whole tumor will result in a higher radiation dose. Single-phase CT might be a useful method in evaluating the degree of angiogenesis. The key point is determining at what exact time to start scanning tumors on single-phase CT.
It is necessary to define an optimized temporal window for scanning of RCC. The time windows for renal scanning are linked to and affected by a number of parameters, including biologic indicators such as weight, heart rate, blood pressure, circulation time, functionality of the heart and kidneys, and so on [36]. We do not think that single-phase scanning can make a definite evaluation of tumor microvasculature, especially for small RCCs, because of these factors. In another of our studies, the optimized temporal window of multiphase dynamic CT for RCC was suggested [7]. We believe that further comparative studies of multiphase and single-phase scanning are needed to determine whether single-phase scanning is sufficient in evaluating the degree of angiogenesis.
In addition, according to the Jinzaki et al. [2] study, the subtype of RCC was one of the important factors affected by the degree of tumor enhancement and the degree of angiogenesis of RCC. In our study, we observed 16 cases of clear cell carcinoma, three cases of granular cell carcinoma, and five cases of mixed-type RCC. Because the numbers of granular cell RCC and mixed-type RCC were small, statistical analyses for each of these subtypes was of no significance. Therefore, additional studies with larger numbers of each subtype of RCC are needed to verify the correlation between the density difference before and after contrast enhancement (Δ H) of RCC and its subtype. We thank Dr. Jinzaki and his colleague for their interest in our study and their valuable comments.

Footnote

WEB—This is a Web exclusive article.

References

1.
Wang JH, Min PQ, Wang PJ, et al. Dynamic CT evaluation of tumor vascularity in renal cell carcinoma. AJR 2006; 186:1423 –1430
2.
Jinzaki M, Tanimoto A, Mukai M, et al. Double-phase helical CT of small renal parenchymal neoplasms: correlation with pathologic findings and tumor angiogenesis. J Comput Assist Tomogr 2000; 24:835 –842
3.
Sheth S, Scatarige JC, Horton KM, et al. Current concepts in the diagnosis and management of renal cell carcinoma: role of multidetector CT and three-dimensional CT. RadioGraphics 2001; 21 [spec no]:S237 –S254
4.
Bosniak MA. The small (≤ 3.0 cm) renal parenchymal tumor: detection, diagnosis, and controversies. Radiology 1991; 179:307 –317
5.
Rubin GD, Napel SA, Leung AN. Volumetric analysis of volumetric data: achieving a paradigm shift. Radiology 1996; 200:312 –317
6.
Berland LL. Slip ring and conventional dynamic hepatic CT: contrast material and timing considerations. Radiology 1995; 195:1 –8
7.
Wang JH, Min PQ, Wang PJ, et al. Optimized temporal window for detection and characterization of renal cell carcinomas with dynamic CT scanning. Chinese J Clin Oncol (English edition)2005; 2:546 –552

Information & Authors

Information

Published In

American Journal of Roentgenology
Pages: W570

Authors

Affiliations

Jin-hong Wang
Tong Ji Hospital Tong Ji University Shanghai, China
Pei-jun Wang
Tong Ji Hospital Tong Ji University Shanghai, China
Xiao-hu Zhao
Tong Ji Hospital Tong Ji University Shanghai, China

Metrics & Citations

Metrics

Citations

Export Citations

To download the citation to this article, select your reference manager software.

There are no citations for this item

View Options

View options

PDF

View PDF

PDF Download

Download PDF

Media

Figures

Other

Tables

Share

Share

Copy the content Link

Share on social media