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Type II lesions usually have a characteristic appearance due to daughter cysts whether or not fluid or matrix are present (Figs. 3.12, 3.14, 3.21, 3.23, 3.24, 3.25, 3.34, 3.35, 3.36, 3.37). Hypermature type II lesions which lack daughters have a non-specific appearance by US and CT (Figs. 3.34 & 3.35), but MRI is helpful as it shows the hypointense pericyst. Fluid in mother cysts has the same appearance as it does in daughters by all methods of cross sectional imaging.

Type III lesions are often discovered on plain films or CT scans (Figs. 3.13, 3.34). They are densely and irregularly calcified and may reveal vestigial evidence of the antecedent type II lesion. Discovery of a type III lesion should provoke a search for uncalcified type I and II cysts in the liver and other organs.

Fig. 3.36 Unruptured type II hydatid cyst in the left lobe of the liver of an Egyptian woman as seen on contrast-enhanced CT scan. Numerous daughter cysts are present.

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Fig. 3.37 Type II hydatids with multiple daughter cysts in 3 different Saudi Arabian patients as seen on (A) ultrasound scan of an abdominal hydatid; (B) CT of a liver hydatid with multiple daughter cysts and brood capsules (connected to germinal layer) from endogenous proliferation; (C) MRI (SE 2000/100) of a hydatid cyst of the right chest wall, sagittal section, showing multiple daughter cysts (arrows); exogenous and endogenous proliferation. There is a low signal intensity rim around the cyst (arrow heads). (Courtesy of Dr. von Sinner and Eur J Rad, 1991).

	Imaging of Unruptured Cysts (continued) Type II lesions usually have a characteristic appearance due to daughter cysts whether or not fluid or matrix are present (Figs. 3.12, 3.14, 3.21, 3.23, 3.24, 3.25, 3.34, 3.35, 3.36, 3.37). Hypermature type II lesions which lack daughters have a non-specific appearance by US and CT (Figs. 3.34 & 3.35), but MRI is helpful as it shows the hypointense pericyst. Fluid in mother cysts has the same appearance as it does in daughters by all methods of cross sectional imaging. Type III lesions are often discovered on plain films or CT scans (Figs. 3.13, 3.34). They are densely and irregularly calcified and may reveal vestigial evidence of the antecedent type II lesion. Discovery of a type III lesion should provoke a search for uncalcified type I and II cysts in the liver and other organs. Fig. 3.36 Unruptured type II hydatid cyst in the left lobe of the liver of an Egyptian woman as seen on contrast-enhanced CT scan. Numerous daughter cysts are present. .... Fig. 3.37 Type II hydatids with multiple daughter cysts in 3 different Saudi Arabian patients as seen on (A) ultrasound scan of an abdominal hydatid; (B) CT of a liver hydatid with multiple daughter cysts and brood capsules (connected to germinal layer) from endogenous proliferation; (C) MRI (SE 2000/100) of a hydatid cyst of the right chest wall, sagittal section, showing multiple daughter cysts (arrows); exogenous and endogenous proliferation. There is a low signal intensity rim around the cyst (arrow heads). (Courtesy of Dr. von Sinner and Eur J Rad, 1991). Next Page Previous Page