Takeharu Yoshikawa MD, Presenter: Nothing to Disclose

Naoto Hayashi MD, Abstract Co-Author: Nothing to Disclose

Eriko Maeda MD, Abstract Co-Author: Nothing to Disclose

Hiroyuki Akai MD, Abstract Co-Author: Nothing to Disclose

Izuru Matsuda MD, Abstract Co-Author: Nothing to Disclose

Kuni Ohtomo MD, Abstract Co-Author: Nothing to Disclose

Hiroki Sasaki, Abstract Co-Author: Nothing to Disclose

Shouhei Hanaoka MD, Abstract Co-Author: Nothing to Disclose

Clinical significance of a small amount of peritoneal fluid collection is not well known in males and postmenopausal females, although it is a familiar finding in premenopausal females. The aim of this study is to investigate the prevalence and, if present, the location and the volume of peritoneal fluid collection in normal males and postmenopausal females on pelvic MRI.

1647 examinees underwent a health screening program using pelvic MRI from April 2009 to March 2010. The following was excluded from the study: 1)patients with malignancy before/during therapy, 2)patients with severe hepatic, renal or peritoneal diseases, 3) examinees who did not undergo pelvic MRI, 4)premenopausal female examinees, and 5) females post hysterectomy, oophorectomy or hormonal therapy. The remaining 1017 males and 313 postmenopausal females were enrolled in the study. Two radiologists independently interpreted MR images (T2-weighted axial and sagittal images and T1-weighted axial images) and judged presence or absence of fluid collection in the peritoneal cavity. After independent interpretation, final decisions were made by consensus of both radiologists. For cases with fluid collection, its location was determined. Polygonal regions of interest were placed to measure area of fluid collection on T2-weighted axial images, and its volume was estimated by multiplying the area by the slice interval (6 mm).

Peritoneal fluid collection was found in 39 out of 1017 males (3.8%) and 52 out of 313 postmenopausal females (16.6%), respectively. Fluid collection was located at or below the level of the third sacral vertebral body in all but one female examinee. The average volume was 3.0 ml ± 2.7 (standard deviation) for males, and 2.3 ml ± 2.0 for postmenopausal females, respectively.

A small amount of peritoneal fluid collection is sometimes observed in normal males and postmenopausal females on pelvic MRI. Normal postmenopausal females have a higher prevalence of peritoneal fluid collection than normal males.

A small amount of peritoneal fluid collection dose not necessarily have clinical significance, and such fluid collection is observed in postmenopausal females with a higher prevalence than males.

Yoshikawa, T, Hayashi, N, Maeda, E, Akai, H, Matsuda, I, Ohtomo, K, Sasaki, H, Hanaoka, S, Peritoneal Fluid Collection in Normal Males and Postmenopausal Females on Pelvic MRI.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11006502.html