Ultrasonography findings and tumour quantification in patients with pseudomyxoma peritonei.

Pseudomyxoma peritonei (PMP) is a disease with various clinical presentations and the diagnostic value of ultrasonography (US) is under investigated. The purpose of this study was to identify the most common US finding in PMP and to investigate US sensitivity, specificity, positive and negative predictive value in quantifying tumour burden in different abdomino-pelvic regions in PMP patients. Between February 2006 and December 2008, 54 patients were treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) due to PMP. The results from preoperative US examination with and without intravenously administrated contrast (SonoVue) were compared to surgical findings. The mean US peritoneal cancer index (PCI) was 6 (range 0-25) and the surgical PCI was 18 (range 3-27) p<0.0001. The histo-pathological subtypes did not influence the US findings. Ascites, bowel loops adhesions and omental cake were mostly visualised correctly by US. The sensitivity of US in quantification of tumour nodules was 91.5% (range 74-100%) and specificity was 33.8% (range 18-55%). The positive predictive value of US examination in PMP was 22% (range 11-44%) and the negative predictive value was 93% (range 77-100%). US can detect the most common PMP findings (ascites and omental cake). The sensitivity of US to quantify PMP tumour burden in different abdominio-pelvic region was relatively high, however, this imaging tool had low specificity.