Polyp detection at 3-dimensional endoluminal computed tomography colonography: sensitivity of one-way fly-through at 120 degrees field-of-view angle.

PURPOSE

To investigate whether increasing the visual field-of-view (FOV) angle at 3-dimensional (3D) endoluminal computed tomography colonography (CTC) from 90 degrees to 120 degrees allows for single pass fly-through examination of the supine and prone views without sacrificing polyp detection.

METHODS

Primary 3D endoluminal CTC evaluation using a 120 degree FOV was performed by 2 experienced radiologists on 73 patients harboring 104 colonoscopy-proven polyps measuring 6 mm or larger. Unidirectional fly-through evaluation consisted of rectal-to-cecal (retrograde) navigation on the supine display and cecal-to-rectal (antegrade) navigation on the prone display. Electronic fluid subtraction was not used.

RESULTS

All 104 (100%) polyps were detectable with the single-pass 3D evaluation on either the retrograde supine or antegrade prone fly-through, with 86 (82.7%) of 104 polyps seen on both fly-through views. Of the 18 polyps detected on only one of the two 3D endoluminal passes (10 prone, 8 supine), 13 were either submerged under fluid (n = 12) or within a collapsed segment (n = 1); therefore, these were also undetectable on the corresponding 90 degrees bidirectional fly-through. The remaining 5 (4.8%) polyps were located behind a fold, but these polyps were all detectable on the other fly-through in the reverse direction.

CONCLUSIONS

Increasing the visual FOV angle to 120 degrees allows for a decrease in the total number of supine and prone 3D endoluminal fly-through passes from 4 to 2 without negatively impacting overall polyp detection.