Acta Radiol Suppl

Peritoneocele. A radiological study with defaeco-peritoneography.

Bremmer S.
Karolinska Institute, Danderyd Hospital, Sweden.
REPORT STUDY: Defaecography reports from 2816 patients were evaluated. Twenty-three percent of the investigations were considered normal, 31% showed rectal intussusception, 13% rectal prolapse, 27% rectocele, and 19% enterocele. A standardised protocol is suggested to ensure a complete evaluation of defaecography. One hundred and ten reports were unclear and reviewed. The unclear reports usually concerned an unexplained widening of the rectovaginal space, and gave incitement to further studies. TECHNIQUE STUDY: Twelve patients with an unexplained widening of the rectovaginal space at defaecography were investigated using defaecography and peritoneography simultaneously, by us named defaeco-peritoneography. All investigations were carried out without complications. Defaeco-peritoneography proved the unexplained widening to be an extension of the pouch of Douglas, a peritoneocele. UNEXPLAINED WIDENING STUDY: Twenty-two patients with unexplained widening of the rectovaginal space noted at defaecography were studied using defaeco-peritoneography. The outline and movements of the peritoneum in the pelvic cavity could be visualised during the dynamic act of defaecation. The unexplained widening of the rectovaginal space was caused completely by a peritoneocele in 14 patients, partially in 6 patients and 2 remained unexplained. However, only 9 out of 22 widenings were peritoneoceles with an enterocele. Just 11 peritoneoceles only contained fluid. Three types of peritoneocele were demonstrated: vaginal, septal, and rectal, with or without enterocele. Combinations of these were also found. RECTAL INTUSSUSCEPTION STUDY: Fifty-seven patients with defaecation disorders were examined using defaeco-peritoneography. Twenty-three patients had rectal intussusception and 7 patients had a rectal prolapse. All these patients had a rectal peritoneocele in the serosal ring-pocket of the rectal intussusception or in the rectal prolapse. Twenty-seven patients had neither rectal intussusception nor rectal prolapse and none of these patients had a rectal peritoneocele. DAILY LIFE STUDY: Twenty-six female patients showing peritoneocele without a contrast-filled rectum at start at defaeco-peritoneography were investigated; 13 of them had enteroceles. Spot radiographs before and after filling the rectum with contrast medium were compared. The peritoneocele disappeared completely in 19 of the patients and was reduced in size in the remaining 7, and the enterocele disappeared completely when the rectum was distended. Defaeco-peritoneography should therefore include a radiograph before the rectum is filled, as it shows the habitual (daily life) anatomy and can disclose pathology as peritoneocele and enterocele. TRANSFORMATION STUDY: Forty-six patients with peritoneocele at defaeco-peritoneography were studied at three different stages during rectal evacuation. At start with contrast-filled rectum, 14 patients had a peritoneocele, and 32 were regarded as normal. At maximum straining, all patients had a peritoneocele and 20 of these were still present after rectal evacuation. The peritoneoceles were largest at straining and rectal types were most common. No enterocele was seen at start. At maximum straining, 21 patients developed an enterocele.

Mangafodipir trisodium (MnDPDP)-enhanced magnetic resonance imaging of the liver and pancreas.

Year 1998
Wang C.
Department of Diagnostic Radiology, Uppsala University, Sweden.
Contrast-enhanced magnetic resonance imaging (MRI) of the liver and pancreas is frequently performed to improve the sensitivity and specificity of lesion detection in these organs. The concept of using tissue-specific contrast media is to selectively enhance the normal parenchyma, but not lesions, so that the contrast between tumorous and normal tissue is increased, and lesion detectability improved. Mangafodipir trisodium (MnDPDP) has been developed as a hepatocellular-specific contrast agent, but uptake has also been found in pancreatic tissue. In this study the safety and diagnostic efficacy of MnDPDP were investigated in both healthy volunteers and in patients with liver and pancreatic tumors. In healthy volunteers (n = 8), dose-dependent enhancement in T1-weighted images was observed in the normal liver and pancreatic parenchyma after infusion of MnDPDP at doses of 5 and 10 mumol/kg. The maximal enhancement in the two dose groups was 77 and 110% in the liver, and 57 and 84% in the pancreas, respectively. The enhancement-over-time profiles demonstrated that the effective imaging window was about 2 h for the liver, and over 4 h for the pancreas. There was no measurable enhancement in brain structures protected by intact blood-brain barrier, and no changes of clinical importance were found in vital signs or in blood and urinary chemistry variables. Compared with unenhanced images (including T2-weighted images), significantly more lesions were detected on MnDPDP-enhanced T1 images in 82 patients with liver tumors (mostly metastases). Features such as rim enhancement and the enhancement in hepatocellular carcinomas can provide information for differential diagnosis. In a study on patients with pancreatic tumors, mainly adenocarcinomas (n = 21) and islet cell tumors (n = 19), two additional lesions were found in the MnDPDP-enhanced images. The contrast enhancement in the pancreatic parenchyma can vary greatly, depending on the site of the enhancing part of the organ in relation to a large tumor. The tumors of both origins were also enhanced post-contrast, but to a lesser degree than the normal pancreatic tissue. MnDPDP enhancement was investigated in 30 liver metastases from endocrine tumors in 13 patients. These lesions showed a signal increase of about 49% post-contrast, which lasted longer than that in the normal liver tissue. The findings may help to distinguish these tumors from other metastatic tumors. T1-weighted sequences of four types, including a spin-echo and three variants of fast gradient-echo sequences, and various parameter combinations, were investigated in healthy volunteers (n = 6), with the aim of finding the optimal sequence for MnDPDP-enhanced MRI of the liver and pancreas. The fat-and-water out-of-phase, fast field (gradient)-echo sequence was the best for imaging of both the liver and pancreas. The studies have shown that MnDPDP is safe when given as an infusion, and is effective as a liver- and pancreas-specific contrast medium, with improved lesion detection in MRI of these organs. It is also useful for the characterization of liver tumors.