67-4

22/90

FactorSex (f:m)Age (years)BUN (mg/dl)Cre (mg/dl)D-dimer (μg/dl)FDP (μg/dl)Hb (g/dl)Ht (%)Plt (104/μl)Values are mean (± standard deviation)BUN : blood urea nitrogen; CRE : creatinine; FDP : fibrinogen degenerative product;Hb : hemoglobin; Ht : hematocrit; Plt : plateletP (HU)T (HU)T/HbT/HtT/PValues are mean (± standard deviation); HU: Hounsfield unit; P: pulmonary blood pool (pulmonary trunk); T: thrombus; *1, thrombus; *2, main pulmonary artery; Hb: hemoglobin; Ht: hematocritThrombi (n=24)10:1467.08 (12.74)20.64 (13.78)0.85 (0.29)22.95 (27.91)48.51 (65.95)12.55 (2.78)38.53 (8.06)24.73 (16.7)Thrombi (n=24)40.01 (12.19)27.25 (7.94)*12.29 (1.13)0.74 (0.36)0.74 (0.27)Non-thrombi (n=16)7:971.88 (12.67)16.27 (4.20)1.07 (0.76)1.17 (1.25)4.70 (3.25)13.59 (2.68)41.42 (7.61)19.77 (12.8)Non-thrombi (n=16)38.07 (9.37)36.66 (6.10)*22.76 (0.44)0.90 (0.12)0.99 (0.13)tive product (FDP) were significantly higher in the thrombi group than in the non-thrombi group (Table 1). The mean attenuation values of pulmonary blood pools in the thrombi and non-thrombi groups were 40.01±12.19 HU and 38.07±9.37 HU, respectively (p=0.594). The mean attenuation values of thrombi in the thrombi group and main PA in the non-thrombi group were 27.25±7.94 HU and 36.66±6.10 HU, respectively (p<0.001). The T/Hb ratio, T/Ht ratio, and T/P ratio in the PTE group were significantly in the non-thrombi group (Table 2). There was no signif-icant difference in the attenuation values between the two CT devices.The performance of unenhanced CT for PTE diagnosis is shown in Table 3. According to the ROC curve (Figure 5), a thrombus cut-off value of 30.85 HU and a T/P ratio cut-off value of 0.835 were associated with moderately accurate diag-nosis of PTE (area under the curve=83.3 and 77.5, respectively). The thrombus sensitivity, specificity, PPV, NPV, and PLR were 79.2%, 87.5%, 90.5%, 73.7%, and 6.33, respectively (Table 3). The T/P 342Table 2　Attenuation values in the pulmonary thrombus and pulmonary blood poolp-value0.594＜0.0010.0150.0120.004lower than those Table 1　Baseline characteristics of patients and initial testing resultsFigure 5　Receiver operating characteristic (ROC) curve of thrombus and the thrombus/pulmonary blood pool ratio.Solid line indicates the ROC of computed tomography (CT) attenuation values of thrombus. The cut-off values are 30.85 Hounsfield units (HU) for thrombus, 0.875 HU for specificity, and 0.792 for sensitivity. Dotted line indicates the ROC of the thrombus/pulmonary blood pool ratio. The cut-off values are 0.835 for the thrombus/pulmonary blood pool ratio, 0.875 for specificity, and 0.667 for sensitivity.p-value0.1670.2880.699<0.0010.0300.0530.0650.2881