CT-Kolonographie - „Virtuelle Koloskopie” - eine aktuelle Übersicht

Zusammenfassung

Diese Übersicht stellt die verfügbaren Daten zur CT-Kolographie zusammen und diskutiert sowohl die technischen als auch medizinischen Aspekte der Entwicklung der letzten 10 Jahre. Obwohl prinzipiell gleichermaßen mit CT wie MRT möglich, wird vorwiegend auf die CT-Technik eingegangen. Die Entwicklung der CT-Technik zum sog. Multi-Detektor-Reihen-CT wird dargestellt und der Einfluss unterschiedlicher Untersuchungstechniken (Schichtdicke, Dosis, Patientenvorbereitung, Nachverarbeitung) erläutert.

Die Methode hat eine hohe Sensitivität, Spezifität und einen hohen negativen Vorhersagewert für Polypen ≥ 1 cm, wobei sie bisher unbefriedigend für Polypen < 5 mm abschneidet. Sie ist eine valide Ergänzung bei inkompletter konventioneller Endoskopie sowie eine Alternative zu „Hochrisiko”-Endoskopien. In der Zukunft wird sie möglicherweise eine Alternative zur konventionellen Endoskopie im Rahmen von Screening-Programmen auf kolorektale Karzinome darstellen.

Abstract

This article reviews published data regarding CT colonography and discusses both technical and medical aspects of its development over the last 10 years. Although colonography can be performed using MRI instead of CT, mainly CT aspects are dealt with. The technical development of CT to the current generation of Multi-detector-row-CT is explained, and the influence of various factors (slice thickness, dose, patient preparation, post processing) is discussed.

The method has a high sensitivity and specifity as well as a high negative predictive value for the detection of polyps ≥ 1 cm, but is currently still insufficient in the detection of polyps < 5 mm. It is a valid alternative after incomplete optical colonoscopy and an alternative in patients with “high-risk” for conventional endoscopy. In the future it may become an alternative for conventional endoscopy in screening programms for colorectal cancer.

Schlüsselwörter

CT-Kolonographie - Kolon - Polypen - Screening - Kolonkarzinom

Key words

CT colonography - colon - polyps - screening - colon carcinoma

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