Multislice Analysis of Blood Flow Values in CT Perfusion Studies of Lung Cancer.
Objectives. Tumour heterogeneity represents a key issue in CT perfusion (CTp), where all studies are usually based on global mean or median values of perfusion maps, often computed on whole tumour. We sought to determine whether, and to what extent, such global values can be representative of tumour heterogeneity, with respect to single slices, and could be used for therapy assessment.Materials and Methods. Twelve patients with one primary non-small cell lung cancer lesion were enrolled in this study, for a total amount of 26 CTp examinations and 118 slices. Mean and median blood flow (BF) values, calculated voxel-based, were computed on each slice and the whole tumour. To measure functional heterogeneity, entropy was calculated on BF values as well.Results. Most of the slices were not represented by the global BF values computed on the whole tumour. In addition, there are a number of lesions having equivalent global BF values, but they are composed of slices having very different heterogeneity distributions, that is, entropy values.Conclusions. Global mean/median BF values of the single slices separately should be considered for clinical assessment, only if interpreted through entropy computed on BF values. The numerical equivalence between global BF values of different lesions may correspond to different clinical status, thus inducing possible errors in choice of therapy when considering global values only.
Department of Electrical, Electronic and Information Engineering (DEI), University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy; Advanced Research Center on Electronic Systems (ARCES), University of Bologna, Via Toffano 2/2, 40125 Bologna, Italy.
Silvia
S
Malavasi
IRCCS-Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST), 47014 Meldola, Italy.
Domenico
D
Barone
IRCCS-Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST), 47014 Meldola, Italy.
Giampaolo
G
Gavelli
Advanced Research Center on Electronic Systems (ARCES), University of Bologna, Via Toffano 2/2, 40125 Bologna, Italy; Department of Computer Science and Engineering (DISI), University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy.
Alessandro
0000-0003-2938-5058
A
Bevilacqua
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019277:Entropy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012039:Regional Blood Flow; D014057:Tomography, X-Ray Computed