| Objective: a.To investigate the perfusion parameters characteristics of CT perfusion imaging in astrocytoma at each levels and to evaltate the value of CTPI in preoperative grading of astrocytoma.b.To evaltate the difference of perfusion parameters in high-grade astrocytoma, meningioma and brain metastases. Materials and Method: Collecting 71 patients with cerebral neoplasm which were confirmed by pathologically. According to the relevant literature establish inclusion and exclusion criteria of patients. Inclusion criteria comprised of :(a)patients who were taken surgery in our hospital neurosurgery and undergone CTPI before surgery in one week;(b)patients with astrocytoma, meningioma or metastatic tumors which were confirmed by pathologically.(c)patients who have no relevant history of encephalopathy, such as stroke, demyelinating white matter lesions, intracranial infection or trauma;(d)patients who have signed the informedconsent form of using iodine contrast agent. The exclusion standards are:(a)the patient with CT contrast agent contraindicated,such as hyperthyroidism, serious cardiovascular,lung,liver,kidney diseases.(b)The day has been used iodine contrast agent.(c) the excessive anxiety patients.(d)the patient who larger than 80 years old, and infant patients. 71 patients are confirmed by postoperative pathology, including 13 cases of low-grade astrocytoma(WHO?-?), 22 cases of high-grade(WHO?-?), 25 cases of meningioma and 11 cases of metastatic tumors. First all the patients are taken head CT scan to determine center of the tumor and then taken perfusion scan by injecting of contrast agen throgh the elbow intravenous bolus simultaneously. Then the original imaging data was transfered into workstation and processed through Brain perfusion software. Tumor perfusion pseudo-color maps were exported through selecting the input artery and output vein manually,which including CBV map, CBF map,MTT map,TTP map and PS map. ROIs outlining in the solid part of the tumor and offside normal brain tissue were based on the maximum intensity projection map and perfusion pseudo-color maps. Finally calculated the perfusion parameters:CBF,CBV,MTT,TTP,PS and getting standardized ratio(tumor solid portion contrasted with offside normal brain tissue) such as r CBV,r CBF,r MTT,r TTP, r PS.Results: a.The perfusion values in low and high-grades astrocytoma are apparently higher than the offside normal brain tissue. The values of CBV,CBF,PS in high-grade astrocytoma were 8.39±1.35 m L/100 g, 107.88±20.02 m L/(100g·min),8.95±0.95 m L/(100g·min),compared with the contralateral the difference was statistically significant(P<0.05),the value of MTT,TTP were 6.65±0.84 s,22.23±4.93 s, compared with the contralateral the difference was no statistically significant(P>0.05). The values of CBV,CBF,PS in low-grade astrocytoma were 4.13±0.98 m L/100, 64.96±12.18 m L/(100g·min),5.56±1.24 m L/(100g·min),compared with the contralateral the difference was statistically significant(P<0.05),the value of MTT,TTP were 6.71±1.00 s,22.14±5.05 s,compared with the contralateral the difference was no statistically significant(P>0.05). b. The values of r CBV, r CBF, r MTT, r TTPand r PS in high-grade astrocytoma were respectively 3.77±0.59,3.14±0.97,0.99±0.09,1.08±0.32,12.85±2.64 and in low-grade astrocytoma were respectively 2.05±0.79,1.78±0.3,1.02±0.20,1.13±0.31,8.18±1.42. There were statistically differences of r CBV?r CBF and r PS values between those two groups(P<0.05),but the value of r MTT,r TTP have no statistically differences(P>0.05). ROC analysis indicated that a cutoff r CBV value of 3.18 with 86.4% sensitivity and 92.3% specificity, r CBF value of 2.55 with 81.8% sensitivity and 100% specificity and r PS value of 10.83 with 77.3% sensitivity and 100% specificity to distinguish high-grade from low-grade astrocytoma. The AUC were respectively 0.941,0.958 and 0.948.(c) The value of r CBV, r CBF, r MTT,r TTP,r PS in meningioma were respectively 7.32±2.08,3.99±0.7,1.01±0.2,1.16±0.5,17.57±2.82 and in metastases were 3.53±0.93,3.21±0.42,1.71±0.28,1.17±0.36,16.09±3.16 respectively. Compared with the high-grade astrocytomas, the value of r CBV and r CBF in meningioma were higher than that in high-grade astrocytoma and metastases and the difference was statistically significant, but these between high-grade astrocytoma and metastases were close that the difference was not statistically significant. The value of r PS in high-grade astrocytomas were lower than that in meningioma and metastases, and the difference was statistically significant, but between meningioma and metastases the difference was not statistically significant.(d) the value of r MTT in metastases were higher than that in high-grade astrocytoma and meningioma and the difference was statistically significant, but between high-grade astrocytoma and meningioma were close that the difference was not statistically significant. Conclusion: a.The CTPI have a high value in evaltated perfusion status and in preoperative grading of astrocytoma.b.The CTPI perfusion parameters have higher value on the differential diagnosis of astrocytoma. |
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