Letters Section Editor: Robert M. Golub,
MD, Senior Editor.
To the Editor: We have a number of concerns
about the study by Dr Cotton and colleagues,1 including
the thickness of the CT slices, the lack of oral contrast, the format for
image interpretation, and variable numbers of patients across institutions.
In our experience, collimation that exceeds 3 mm substantially reduces image
quality and lesion conspicuity. Similarly, other studies suggest that oral
contrast should be routinely administered.2,3 The
selection of slice-by-slice viewing for primary CTC interpretation over an
appropriate 3-dimensional volume rendering or fly-through viewing system also
may have made CTC less sensitive in identifying lesions.4 Finally,
a single institution with experienced readers contributed 30% of the cases.
In the other institutions, the readers' lack of experience in CTC may be another
reason why the apparent sensitivity was lower in these institutions.
Summers RM, Bitter I, Petrick N. Virtual Colonoscopy. JAMA. 2004;292(4):431-433. doi:10.1001/jama.292.4.432-b