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Figure 1. Transverse multi-detector row CT images of the phantom thorax and calibration insert obtained with (left) a 3-mm section width protocol and (right) a 1.25-mm section width protocol. At the same threshold of 130 HU, a fine spotty calcified cylinder (arrowhead) with the actual CaHA mass of 0.6 mg is visible but undetectable with the quantification software on the 3-mm section width image, whereas it is clearly revealed and measurable on the 1.25-mm section width image.