Absolute cerebral blood flow: assessment with a novel low-radiation-dose dynamic CT perfusion technique in a swine model.

Abstract

RATIONALE AND OBJECTIVES\nTo validate the accuracy of a novel low-dose dynamic CT perfusion technique in a swine model using fluorescent microsphere measurement as the reference standard.\n\n\nMATERIALS AND METHODS\nContrast-enhanced dynamic CT perfusion was performed in five swine at baseline and following brain embolization. Reference microspheres and\xa0intravenous contrast (370 mg/ml iodine, 1 ml/kg)\xa0were injected (5 ml/s), followed by dynamic CT perfusion. Scan parameters were 320×0.5 mm, 100 kVp and 200 mA. On average, 47 contrast-enhanced volume scans were acquired per acquisition to capture the time attenuation curve. For each acquisition, only two systematically selected volume scans were used to quantify brain perfusion with\xa0first-pass analysis technique. The first volume scan was selected at the base, simulating bolus tracking, while the second volume\xa0at the peak of the time attenuation curve similar to a CT angiogram. Regional low-dose CT perfusion measurements were compared to the microsphere perfusion measurements with t-test, linear regression and Bland-Altman analysis. The radiation dose of the two-volume CT perfusion technique was determined.\n\n\nRESULTS\nLow-dose CT perfusion measurements (PCT) showed excellent correlation with reference microsphere perfusion measurements (PMICRO) by PCT\xa0= 1.15 PMICRO\xa0- 0.01 (r\u202f=\u202f0.93, p\xa0≤\xa00.01). The CT dose index and dose-length product for the two-volume CT perfusion technique were 25.6 mGy and 409.6 mGy, respectively.\n\n\nCONCLUSIONS\nThe accuracy and repeatability of a low-dose dynamic CT perfusion technique was validated in a swine model. This technique has the potential for accurate diagnosis and follow up of stroke and vasospasm.