CT prediction of the Fuhrman grade of clear cell
renal cell carcinoma (RCC): towards the
development of computer-assisted diagnostic
method
Hannu Huhdanpaa ,
1
Darryl Hwang,
1
Steven Cen,
1
Brian Quinn,
1
Megha Nayyar,
1
Xuejun Zhang,
2
Frank Chen,
1
Bhushan Desai,
1
Gangning Liang,
3
Inderbir Gill,
3
Vinay Duddalwar
1
1
Department of Radiology, University of Southern California, 1500 San Pablo St, 2nd floor imaging, Los Angeles, CA 90033, USA
2
Viterbi School of Engineering, University of Southern California, Los Angeles, USA
3
Department of Urology, University of Southern California, 1441 Eastlake Ave, NOR 7416, Los Angeles, CA 9003, USA
Abstract
Purpose: There are distinct quantifiable features charac-
terizing renal cell carcinomas on contrast-enhanced CT
examinations, such as peak tumor enhancement, tumor
heterogeneity, and percent contras t washout. While
qualitative visual impressions often suffice for diagnosis,
quantitative metrics if developed and validated can add
to the information availa ble from standard of care
diagnostic imaging. The purpose of this study is to assess
the use of quantitative enhancement metrics in predicting
the Fuhrman grade of clear cell RCC.
Materials and methods: 65 multiphase CT examinations
with clear cell RCCs were utilized, 44 tumors with
Fuhrman grades 1 or 2 and 21 tumors with grades 3 or 4.
After tumor segmentation, the following data were
extracted: histogram analysis of voxel-based whole lesion
attenuation in each phase, enhancement and washout
using mean, median, skewness, kur tosis, standar d devi-
ation, and interquartile range.
Results: Statistically significant difference was observed
in 4 measured parameters between grades 1–2 and grades
3–4: interquartile range of nephrographic attenuation
values, standard deviation of absolute enhancement, as
well as interquartile range and standard deviation of
residual nephrographic enhancement. Interquartile range
of nephrographic attenuation values was 292.86 HU for
grades 1–2 and 241.19 HU for grades 3–4 (p value 0.02).
Standard deviation of absolute enhancement was 41.26
HU for grades 1–2 and 34.66 HU for grades 3–4 (p value
0.03). Interquartile range was 297.12 HU for residual
nephrographic enhancement for grades 1–2 and 235.57
HU for grades 3–4 (p value 0.02), and standard deviation
of the same was 42.45 HU for grades 1–2 and 37.11 for
grades 3–4 (p value 0.04).
Conclusion: Our results indicate that absolute enhance-
ment is more heterogeneous for lower grade tumors and
that attenuation and residual enhancement in nephro-
graphic phase is more heterogeneous for lower grade
tumors. This represents an important step in devising a
predictive non-invasive model to predict the nucleolar
grade.
Key words: Renal cell carcinoma—Quantitative
imaging—Computer-assisted diagnosis—Computed
tomography (CT)
Renal cancer accounts for more than 2% of cancers in
humans worldwide [1]. In the United States, the annual
incidence of renal cancer increased yearly by 1.6% over
the past decade, with over 63,000 new cases in 2014 [2]. A
majority of renal tumors are incidentally diagnosed on
medical imaging, being often asymptomatic, small in
size, and early stage [3, 4].
IRB Statement: This was institutional review board-approved, Health
Insurance Portability and Accountability Act-compliant retrospective
study.
Correspondence to: Hannu Huhdanpaa; email: huhdanpa@uw.edu;
hannu.huhdanpaa@med.usc.edu
Springer Science+Business Media New York 2015
Abdominal
Imaging
Abdom Imaging (2015)
DOI: 10.1007/s00261-015-0531-8