Development of Prediction of Radiation Pneumonitis by Phase-Contrast Cine MR Sequence

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The detailed investigation was carried out on 18 cases of primary lung and 22 cases of primary esophageal cancer who underwentradiotherapy treatment in the study duration for 3 years from the 1999 fiscal year and cine MRA depicting the pulmonary arterial time-velocity curve before therapy. Radiation pneumonitis (RP) of grade 2 or more occurred in 5 cases of lung cancer including 2 cases of grade 2, 2 of grade 3, and 1 of grade 4, RP occurred in 4 cases of esophageal cancer including 2 cases of grade2, 1 of grade 3, and 1 of grade 4.The cases, which cause the RP, are assumed that the pulmonary vascular resistance is a high condition because of their background of pulmonary diseases such as pulmonary fibrosis, therefore, we examined the following. Time-velocity curve obtained by cine MRA of the right and left pulmonary artery respectively was analyzed before the treatment start on total of the 40 cases using the digitizer. And area at the peak from the cardiac contraction start (the peak … More region area), peak velocity, time at the park from the contraction start (peak time), maximum acceleration at contraction, half-value width to the peak, and maximum acceleration/peak region area were measured. These values were compared between the RP and non-RP groups. Irradiated unilateral lung in the lung cancer cases and irradiated bilateral lung in esophageal cancer cases were entered in this study. Equal dividing powder t-test was used in the test.The result recoanizes the significance at peak region area, peak time, half-value width to the peak, maximum acceleration/peak region area, and the most significant factor was peak time showing less than 0.001 value. In making mean value 111ms of the peak time of the RP group to be the cut off value, sensitivity, specificity, overall predictive value were 58 % 88 % and 83 % respectively. Various factors obtained from pulmonary arterial time-velocity curve from phase-contrast cine MRA are useful in predicting radiation pneumonitis. Especially, usefulness of the peak time I.e. the time until flow velocity reaches the peak from the contraction stage start is high, because it can be conveniently measured without usage of a digitizer. Less