[Ultrasonography of the normal vermiform appendix].
OBJECTIVE
To study the detectability and the appearance of the vermiform appendix with ultrasound in asymptomatic adults.


METHODS
A prospective study was performed on 300 patients, selected without regard to age, sex and weight. We tried to visualize the appendix with a 3.5 MHz annular array and a 5 MHz linear array transducer.


RESULTS
In 63% of the patients the appendix was clearly visualised. The main reasons for non-visualisation were obesity with insufficient ultrasound penetration (38%) and the caecum laying in pelvic or atypical position (24%). In 31%, no cause was apparent but we assume that the appendix often lies behind the caecum. The sonographic image showed an aperistaltic target originating at the caecum, and ending blindly. In 42% of cases the appendix was ovoid in transverse section; in 32%, round; and in 26% both forms were found within one appendix. Intraluminal gas was visible in 86%. The mean transverse diameter was 5.2 mm (min. 3 mm, max. 13 mm) and in 76% the transverse diameter was lower than 6 mm.


CONCLUSIONS
The sonographic detectability, the appearance and the size of the normal appendix show considerable variations.
Rettenbacher
T
T
Abteilung für Röntgendiagnostik und Nuklearmedizin Krankenhaus der Barmherzigen Brüder in Salzburg.
Hollerweger
A
A
Macheiner
P
P
Gritzmann
N
N
D000328:Adult; D000886:Anthropometry; D001064:Appendicitis / Q000000981:diagnostic imaging; D001065:Appendix / Q000000981:diagnostic imaging*; D005260:Female; D005740:Gases; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012016:Reference Values; D014463:Ultrasonography
D005740:Gases