Contrast-enhanced color duplex sonography (CDS): an alternative for the evaluation of therapy-relevant tumor oxygenation?
OBJECTIVE
To evaluate the predictive value of radiotherapeutically relevant tumor hypoxia by contrast-enhanced color duplex sonography (CDS). The objectification was based on pO(2) histography.


METHODS
25 patients with metastatic neck lymph node from a primary squamous carcinoma of the head and neck were examined. To visualize as many vessels as possible, a contrast enhancer (Levovist), Schering Corp., Germany) was administered. Horizontal and longitudinal sonographic scans with a thickness of 5 mm were performed on the metastatic neck lymph node. Color pixel density (CPD) was defined as the ratio of colored to gray pixels in a region of interest. It represents the extent of vascularization in the investigated slice. To assess the biological and clinical relevance of oxygenation measurement, the relative frequency of pO(2) readings < or = 2.5, 5.0, and 10.0 mmHg, as well as mean and median pO(2), were documented.


RESULTS
In order to investigate the degree of linear association, the Pearson correlation coefficient was calculated. Moderate (/r/ > 0.5) to high (/r/ > 0.7) correlation was found between the CPD and the parameters of hypoxic fraction (pO(2) readings with values < or = 5.0 and 10.0 mmHg, as well as mean and median). There was only a slight correlation between CPD and the fraction of pO(2) values < or = 2.5 mmHg (r = -0.479).


CONCLUSIONS
CPD represents the mean degree of vascularization. As a noninvasive measurement, this method seems feasible for evaluating the state of global oxygenation in superficial tumors. Nevertheless, this method is limited through its deficiency in describing the vascular heterogeneity of tumors.
Gagel
Bernd
B
Department of Radiotherapy, University of Aachen, Aachen, Germany.
DiMartino
Ercole
E
Schramm
Oliver
O
Pinkawa
Michael
M
Piroth
Marc
M
Demirel
Cengiz
C
Maneschi
Payam
P
Stanzel
Sven
S
Asadpour
Branka
B
Westhofen
Martin
M
Eble
Michael J
MJ
D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000556:secondary*; D003287:Contrast Media; D018618:Echocardiography, Doppler, Color / Q000379:methods*; D005260:Female; D006258:Head and Neck Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000378:metabolism; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D010100:Oxygen