Study Of The Technique Of Multi-slice Spiral CT Perfusion And Its Application Of Thyroid Disease

Objective: To investigate the technique of Multi-slice Spiral CT perfusion with body tumor software package and evaluate the diagnosis value of its application of thyroid disease.Methods: The multi-slice dynamic CT perfusion series was performed for thyroid perfusion with cine mode (1 s per rotation) on a multi-slice CT scanner (Lightspeed QX/i, GE) , 4 ×5 mm collimation , 120 kV , 60 mA. Contrast injection was done by using 50 ml nonionic contrast agent (300 mg I/ ml), at a flow rate of 3 ml/ s with a power injector, and 8 seconds delay, and data acquisition lasted for 55 seconds. The parameters of CT perfusion such as blood flow(BF),blood volume(BV), mean transit time (MTT), and permeability surface(PS)were measured and statistically analyzed in patients with normal thyroid ( n = 21) , thyroid carcinoma ( n = 32) ,and benign thyroid disease ( n = 69) including thyroid adenoma in 31cases and nodule goiter in 38 cases proven by pathology , respectively , on a Sun Ultra AW4.0 workstation using Perfusion 2 software package ( GE) with deconvolution method.Results: The images of perfusion with multi-slice CT could be readily obtained. Perfusion images can clearly and directly display tumor diameter and outlines and quantitatively monitor blood perfusion status of tumor inner structures .The mean BF , BV ,MTT, and PS in normal thyroid tissue were (549.61±187.91)ml/100g·min,(9.34±3.41)ml/100g,( 2.65±0.97)s,( 36.07±25.11) ml/100g·min , respectively. The mean BF , BV ,MTT, and PS in thyroid carcinoma were (326.81±229.14)ml/100g·min,(7.95±5.65)ml/100g,( 3.90±2.60)s,( 54.06±22.95) ml/100g·min, respectively. The mean BF , BV ,MTT, and PS in benign group were (330.53±244.02)ml/100g·min,(8.14±5.33)ml/100g,( 3.87±2.56)s,(41.84±24.54) ml/100g·min, respectively. The mean BF and PS among three groups had significant difference(P=0.001,0.018). However, the mean BV and MTT were not statistically significant (P= 0.586, 0.104). The differences in BF were statistically significant between normal thyroid and malignant group, between normal thyroid and benign group(P=0.000,0.001), and there was no statistically significant difference between malignant group and benign group(P=1.000). The differences in PS were statistically significant between malignant group and normal thyroid, between malignant group and benign group (P=0.009, 0.020), and PS between normal thyroid and benign group had no significant difference(P=0.341). When PS≥50 ml/100g·min was set as a diagnostic threshold, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 71%, 62.5%, 68.3%, 68.3%, 80.3% and 50%.Conclusion: The technique of Multi-slice Spiral CT perfusion is simple, feasible and noninvasive. The value of PS in benign and malignant tumors has significant difference. Perfusion MSCT is valuable for the differentiation of benignancy from malignancy in thyroid.