A comparison of primary two- and three-dimensional methods to review CT colonography

Abstract

The aim of our study was to compare primary three-dimensional (3D) and primary two-dimensional (2D) review methods for CT colonography with regard to polyp detection and perceptive errors. CT colonography studies of 77 patients were read twice by three reviewers, first with a primary 3D method and then with a primary 2D method. Mean numbers of true and false positives, patient sensitivity and specificity and perceptive errors were calculated with colonoscopy as a reference standard. A perceptive error was made if a polyp was not detected by all reviewers. Mean sensitivity for large (≥10 mm) polyps for primary 3D and 2D review was 81% (14.7/18) and 70% (12.7/18), respectively (p-values ≥0.25). Mean numbers of large false positives for primary 3D and 2D were 8.3 and 5.3, respectively. With primary 3D and 2D review 1 and 6 perceptive errors, respectively, were made in 18 large polyps (p=0.06). For mediumsized (6-9 mm) polyps these values were for primary 3D and 2D, respectively: mean sensitivity: 67%(11.3/17) and 61%(10.3/17; p-values≥ 0.45), number of false positives: 33.3 and 15.6, and perceptive errors : 4 and 6 (p= 0.53). No significant differences were found in the detection of large and medium-sized polyps between primary 3D and 2D review.

Role of CT colonography in colorectal cancer screening: risks and benefits

“…This was confirmed in a recent meta-analysis with a pooled sensitivity of 83% for studies with primary 3-D imaging compared to 64% for primary 2-D imaging 21. However, some studies have found a primary 2-D approach to be comparable to a primary 3-D endoluminal analysis 33 34. Data suggest that computer-aided detection (CAD) systems might be helpful for evaluating CTC images 35 36…”

Does a computer-aided detection algorithm in a second read paradigm enhance the performance of experienced computed tomography colonography readers in a population of increased risk?

“…Although the discussion as to whether to read the data in 2D or 3D is still not settled, a (slight) superiority in terms of polyp detection with 3D is reported by some studies [37,38]. Since the reported sensitivities of a primary 2D paradigm tend to be lower, CAD may have a larger additional value when used in a 2D reading protocol.…”

CT colonography: Project of High National Interest No. 2005062137 of the Italian Ministry of Education, University and Research (MIUR)

“…Once the CT volume has been acquired (preferably with low-dose, thinsection multislice imaging) [1,2], the native images can be directly viewed on the monitor of the reporting workstation (2D technique) or processed on dedicated workstations for intraluminal viewing (virtual endoscopic or 3D technique). Many authors agree that the diagnostic efficiency of CT colonography is improved by using the two visualisation techniques in combination [2,3]. In Italy, CT colonography has been in clinical use for several years.…”

“…Per far questo sono requisiti essenziali la adeguata pulizia intestinale e la distensione del colon ottenute con metodi specifici. Una volta condotta l'acquisizione del volume TC (preferibilmente con metodica multistrato con bassa dose e spessori di strato sottili) [1,2] [2,3]. In Italia la CV è in uso clinico da ormai alcuni anni.…”