ABSTRACT
Purpose To investigate the influence of the region of interest (ROI) selection on the repeatability of 64 slice spiral CT perfusion parameters for the peripheral lung cancer.Materials and Methods The 64 slice spiral CT perfusion images of thirty-seven patients with peripheral lung cancer were retrospectively analyzed.The perfusion parameters including blood flow (BF),blood volume (BV),Patlak blood volume (PBV),permeability surface area product (PS),and mean transit time (MTT) were obtained by using three ROI selection methods including maximum area of ROI (ROIm),round of ROI (ROIr),and volume of ROI (ROLv),and these parameters were measured by two observers repeatedly.The repeatability and reliability of the values of these perfusion parameters by using different ROI methods or measured by different observer were determined.Results The perfusion parameters derived from three ROIs all had a excellent intraobserver and interobserver agreement (ICC＞0.75).Besides,the values of the perfusion parameters by using different ROI methods had no significant difference (P＞0.05),but the data obtained by ROIm and ROIv were more stable than that obtained by ROIr.Conclusion The repeatability of the perfusion parameters obtained from above three ROIs is excellent,but ROIm and ROIv may be more suitable than ROIr to assess vascular perfusion of peripheral lung cancer.
ABSTRACT
Objective To investigate the value of early?phase enhancement ratio combined with peripheral vascular diameter in the differential diagnosis of benign and malignant breast lesions using 3.0 T dynamic contrast?enhanced magnetic resonance imaging (DCE?MRI). Methods Sixty seven cases of patients (35 with malignant lesions and 32 with benign lesions in the breasts) were retrospectively analyzed. Their diagnoses were confirmed by surgery and pathology and all the patients underwent breast MRI plain scan and DCE?MRI in the two weeks before surgery. Lesion ROIs were drawn and time?signal intensity curves in the DCE?MRI were generated. Early?phase enhancement rate, time to peak, early?phase enhancement ratio, numbers of tumor vessel within 3 cm of the lesion and diameter of the largest vessel were recorded. Mann?Whitney U test was used to compare the difference of DCE?MRI between benign and malignant lesions, and the ROC curve was used to evaluate the efficiency of early?phase enhancement rate, early?phase enhancement ratio and vascular diameter in differentiating benign and malignant lesions. Results With breast malignant lesions, the medians of time to peak, early?phase enhancement rate, early?phase enhancement ratio, numbers of tumor vessel and vascular diameter were 2.2 s, 176.0%, 100.0%, 4 and 2.96 mm respectively, while with benign lesions of these parameters were 4.7 s, 113.3%, 81.9%, 0 and 0.00 mm respectively, and the differences were statistically significant (all P<0.05).When early?phase enhancement rate was used for differential diagnosis of breast benign and malignant lesions, the area under the ROC curve was 0.702 and the sensitivity and specificity were 82.86%and 56.25%with a threshold of 120.0%. When early?phase enhancement ratio was used, the area under the ROC curve was 0.854 and the sensitivity and specificity were 94.29% and 68.75% with a threshold of 86.0%. When peripheral vascular diameter was used, the area under the ROC curve was 0.896 and the sensitivity and specificity were 74.29%and 84.38% with a threshold of 2.78 mm. When early?phase enhancement ratio was combined with peripheral vascular diameter, the area was 0.925 and the sensitivity and specificity were 97.14% and 62.50%. Conclusion In the differential diagnosis of benign and malignant breast lesions under DCE?MRI, early?phase enhancement ratio combining with peripheral vascular diameter has improved sensitivity.