Hepatic enhancement in colorectal cancer: texture analysis correlates with hepatic hemodynamics and patient survival.
OBJECTIVE
Perfusion imaging of the liver has attracted interest as a potential means for earlier detection of hepatic metastases, but the techniques are complex and do not form part of routine imaging protocols. This study assesses whether the hemodynamic status of the liver of patients with colorectal cancer but apparently normal hepatic morphology is reflected by texture features within a single portal-phase contrast enhanced computed tomography (CT) image and correlates texture with overall survival.


METHODS
Portal-phase CT images from 27 patients with colorectal cancer but no apparent hepatic metastases were processed using a band-pass filter that highlighted image features at different spatial frequencies. A range of parameters reflecting liver texture on filtered images were correlated against CT hepatic perfusion index (HPI) and patient survival.


RESULTS
After image filtration, entropy values from hepatic regions were inversely correlated with HPI (r=-0.503978, P=.007355), and directly correlated with survival (r=0.489642, P=.009533). An entropy value below 2.0 identified four patients who died within 36 months of their CT scan with sensitivity 100% and specificity 65% (P<.03).


CONCLUSIONS
The hemodynamic status of the liver is reflected by subtle changes in coarse texture on portal phase images that can be revealed by texture analysis. Texture analysis has the potential to identify colorectal cancer patients with an apparently normal portal phase hepatic CT but reduced survival.
Ganeshan
Balaji
B
Department of Engineering & Design, University of Sussex, Brighton BN1 9QT, UK. b.ganeshan@sussex.ac.uk
Miles
Kenneth A
KA
Young
Rupert C D
RC
Chatwin
Chris R
CR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003973:Diatrizoate; D019277:Entropy; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics / Q000502:physiology; D006499:Hepatic Artery; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007479:Iopamidol; D008099:Liver / Q000098:blood supply / Q000000981:diagnostic imaging*; D008102:Liver Circulation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein; D011856:Radiographic Image Enhancement / Q000379:methods*; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D003973:Diatrizoate; D007479:Iopamidol