Dynamic Contrast-enhanced CT for Prostate Cancer: Relationship between Image Noise, Voxel Size, and Repeatability

Abstract

Purpose:To evaluate the relationship between image noise, voxel size, and voxel-wise repeatability of a dynamic contrast agent-enhanced (DCE) computed tomographic (CT) examination for prostate cancer. Materials and Methods:This prospective study was approved by the local research ethics committee, and all patients gave written informed consent. Twenty-nine patients (mean age, 69.1 years; range, 56-80 years) with biopsy-proved prostate cancer underwent two DCE CT examinations within 1 week prior to radiation therapy. Parameter maps of transfer constant ( K trans ), the fraction of blood plasma (v p ) , the fraction of extravascular extracellular space (v e ) , and the fl ux rate constant between the extravascular extracellular space and plasma ( k ep ) were calculated at 15 different image resolutions, with kernel sizes ranging from 0.002 to 2.57 cm 3 . Statistical analysis to quantify the voxel-wise repeatability was performed by using a Bland-Altman analysis on all tracer kinetic model parameter maps of each patient. From this analysis, the within-voxel standard deviation (wSD) was calculated as a function of spatial resolution. Results:A kernel size in the range of 0. Conclusion:There is a high voxel-wise repeatability of the DCE CT imaging technique for prostate cancer for kernel sizes as small as 0.1 cm 3 . With the relationship between kernel size, image noise and voxel-wise repeatability, it becomes possible to estimate for alternative DCE CT protocols (eg, those with a reduced radiation dose) at what kernel size a suffi cient repeatability can be obtained.q RSNA, 2010

Functional MRI for radiotherapy dose painting

“…Nevertheless, large differences have been reported in the value of the transfer constant, K trans , in healthy (0.06–0.60 min −1 ) and cancerous (0.18–1.26 min −1 ) prostate tissue [54–60]. This variation is not caused by a day-to-day variability in the patient, as the within subject standard deviation (wSD) of K trans from DCE-MRI is reported to be small (wSD=0.10 min −1 for MRI, 0.047 for voxels of 0.15 cc on DCE-CT) [61]. Thus, further standardization in methodology may result in a more robust quantification of DCE-MRI, making it even more attractive for use in dose painting,…”

Perfusion MDCT of Prostate Cancer: Correlation of Perfusion CT Parameters and Immunohistochemical Markers of Angiogenesis

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Technical prerequisites and imaging protocols for CT perfusion imaging in oncology

“…Fig. 5 is based on a measured population AIF determined from the femoral artery of 28 patients in a prostate cancer DCE-CT study [44]. Blood volume is assumed to be constant (10 ml/100 ml); the exact value of blood volume is of lesser importance as it will mainly scale the enhancement curves.…”