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 The walls of peritoneal cavity as well as abdominal and pelvic organs contained within are lined with peritoneum


two to three times greater than on the left side. The reason is that the major flow route from the pelvis is through the right paracolic gutter because of the shallow left paracolic gutter and the limited spreading caused by the phrenicocolic ligament (see figure 7). The Morison pouch, the most dependent recess, is the most common site of perihepatic abscess  Actinomycosis causing fistulas or sinus tracts and the lack of or minimal ascites and regional lymphadenopathy may help differentiate actinomycosis from malignant tumour (see figure 8).


CONDITIONS PRODUCING AIR ATTENUATION  Any hollow viscus perforation or benign conditions such as ruptured pneumatosis intestinalis, downward tracking of pneumomediastinum, or leakage through a distended loop of bowel can also produce pneumoperitoneum. Therefore, extraluminal air is not always a pathognomonic finding of bowel perforation  CT is the standard of reference for detection, localization and origin with use of wide window settings (see figure 3).


CONDITIONS PRODUCING FAT ATTENUATION  Ruptured Teratoma  Liposarcoma may arise in any region of the body that contains fat  PseudoLipoma arise from a detached piece of colonic fat that lodge between the diaphragm and the superior aspect of the liver (see figure 4).  Juxtacaval Fat commonly seen in 0.5% of


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adults undergoing abdominal CT and is a normal variant (see figure 5).  Omental Infarct is due to kinking of veins secondary to increased intra- abdominal pressure, and postprandial vascular congestion


PERIHEPATIC FLUID COLLECTIONS Ascites is defined as an abnormal amount of intraperitoneal fluid. Accumulations of blood, urine, chyle, bile, or pancreatic juice are more unusual causes. Ascites usually demonstrates low attenuation values 0 - 20 HU however acute intraperitoneal blood is of high attenuation 20 - 90 HU (see figure 6) and Tuberculous ascites typically has high attenuation 20 - 45 HU due to its high protein and cellular contents.


PERIHEPATIC INFECTIONS  Perihepatic Abscess  Perihepatic Tuberculous Abscess The frequency of subhepatic and subphrenic abscesses on the right side is


PERITONEAL NEOPLATIC LESIONS Peritoneal carcinomatosis is malignant seeding of the peritoneum, and this is the most common peritoneal malignancy. It most commonly arises from the ovary, colon, stomach, and pancreas (see figures 9,10). Pseudomyxoma Peritonei is characterized by the gradual accumulation of large volumes of gelatinous ascites in the peritoneal cavity, which comes from ruptured mucin- producing tumours of the ovary or appendix (see figure 11).


CONCLUSION The distribution of fluid plays a significant role in the spread of inflammation and metastatic disease in the peritoneal cavity. Therefore, squeal of ruptured hollow viscera, ruptured fatty tumours, peritoneal infections and seeded perihepatic metastases are not uncommon. CT scans play a vital, accurate and cost-effective tool to evaluate the various pathologies involving peritoneal spaces and causing direct invasion, subperitoneal extension, or extension along the lymphatics. ■


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 REFERENCES References available on request (magazine@informa.com)


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