Decay constant of Doppler flow waveform as a possible indicator of ovarian malignancy

Ron Tepper, Laurence Keselbrener, Moshe Manor, Shulamit Eyal, Yoram Beyth, Yair Zimmeri, Solange Akselrod*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The objectives of this study were to analyze the decay constant (τ) of the Doppler flow waveform in ovarian tumors; to determine if differences in this constant can discriminate between malignant and benign ovarian tumors; and to compare the decay constant to the known resistive index (RI), in order to determine its potential prognostic application. Patients with ovarian masses (46) were evaluated in a retrospective study; 13 had malignant tumors, 7 showed tumors with low malignant potential (LMP), 11 had benign masses, 4 had secondary ovarian metastases and 11 had functional ovarian masses. Doppler flow waves measured in the ovary before operation were analyzed from archival videotapes. The RI was calculated preoperatively, and the decay constant of the flow waveform was analyzed retrospectively. We approximated the decaying portion of the flow waveform from the systolic peak to the diastolic level to an exponential curve. Then, the decay constant associated with the flow signal was compared for different types of ovarian pathology. Ovaries with malignancies showed significantly higher mean values for the decay constant (89.7; 95% confidence interval 60.0-119.3) than those with benign tumors (41.8; 25.7-57.9) (p < 0.007), where τ is provided in pixels (in this study each pixel equals approximately 11.4 ms). The mean RI value for malignant tumors was 0.44 ± 0.12 whereas, in benign tumors, it was 0.622 ± 0.11. For the benign tumors, both τ and RI did not differ significantly from the measured indices in LMP tumors, metastases and functional ovarian findings. In addition, when the cutoff value of τ was set at 48, 92.3% of all malignancies were identifiable using only τ. This preliminary study indicates that the decay constant of the Doppler flow waveform is able to discriminate between malignant and benign masses and may, thus, provide substantial assistance as an additional parameter in the diagnosis of malignant ovarian tumors in postmenopausal patients.

Original languageEnglish
Pages (from-to)1171-1177
Number of pages7
JournalUltrasound in Medicine and Biology
Issue number8
StatePublished - 1997
Externally publishedYes


FundersFunder number
Tel Aviv University


    • Decay constant
    • Doppler flow waveform
    • Ovarian neoplasm


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