Abstract
Purpose
In the framework of the 3-year project of the Italian Legatumori (2003–2006), we evaluated the diagnostic accuracy of computed tomography (CT) colonography in detecting colorectal lesions in a screening population with positive faecal occult blood test (FOBT).
Materials and methods
Two hundred and thirty asymptomatic subjects (age range 45–80 years) were enrolled in the study. CT colonography was performed with standard patient preparation (no faecal tagging) and a 4-detector-row CT scanner. Image analysis was carried out with primary 2D analysis and the use of 3D endoluminal views to solve difficult cases. Patients were referred for conventional colonoscopy in the following situations: detection of three or more suspected lesions with maximum diameter ≤6 mm; evidence of one or more lesions with maximum diameter >6 mm; presence of colonic masses (maximum diameter >3 cm).
Results
CT colonography detected colonic masses in 12 out of 135 subjects (8%). It generated 93 false positives and 19 false negatives in the identification of diminutive lesions (≤6 mm), and 70 false positives and six false negatives in lesions >6 mm. Sensitivity was 83% in smaller lesions and 93% in lesions >6 mm; specificity was 45% and 59%, respectively.
Conclusions
In a screening population with positive FOBT, CT colonography without faecal tagging and no definite size threshold for the reporting of polyps showed very low specificity but high sensitivity in the detection of all colorectal lesions.
Riassunto
Obiettivi
Nell’ambito di un progetto triennale finanziato dalla Legatumori (2003–2006) è stata valutata l’accuratezza diagnostica della CV nel rilievo di lesioni colorettali in una popolazione di screening risultata positiva al test per il SOF.
Materiali e metodi
Sono stati inclusi nello studio 230 soggetti asintomatici. La CV era eseguita con preparazione standard (senza fecal tagging) e apparecchiatura TC a 4 strati. L’analisi delle immagini era effettuata con valutazione primaria 2D e uso delle ricostruzioni 3D nei casi dubbi. L’esame di CC veniva indicato in presenza di: almeno 3 lesioni sospette per polipi con diametro inferiore o uguale a 6 mm, almeno 1 lesione con diametro superiore a 6 mm, o masse coliche (diametro massimo >3 cm).
Risultati
La CV ha consentito la diagnosi di masse coliche in 12/135 (8%) pazienti; ha generato 93 falsi positivi e 19 falsi negativi per polipi di dimensioni minori o uguali a 6 mm, e 70 falsi positivi e 6 falsi negativi per polipi di dimensioni maggiori. La sensibilità era quindi 83% per polipi clinicamente non significativi e 93% per quelli con diametro superiore a 6mm; la specificità rispettivamente di 45% e 59%.
Conclusioni
In una popolazione di screening con SOF+, la CV senza fecal tagging e senza l’adozione di un cut off dimensionale nella indicazione alla colonscopia tradizionale, ha evidenziato una bassa specificità, a fronte Pickdi una elevata sensibilità nel rilievo di tutte le lesioni.
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Neri, E., Vagli, P., Turini, F. et al. Diagnostic accuracy of CT colonography in patients with positive faecal occult blood test: results of the Italian project Legatumori 2003–2006. Radiol med 114, 586–594 (2009). https://doi.org/10.1007/s11547-009-0342-x
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DOI: https://doi.org/10.1007/s11547-009-0342-x