MRI accurately determines right lobe mass. Most liver regeneration occurs in the 1st week after resection or transplantation, and the time course does not differ significantly in donors or recipients. The mass of the graft or remnant segment affects the duration of the regeneration process, with a smaller initial liver mass prolonging the course. Steatosis of <30% had no bearing on liver function or regeneration and, therefore, should not be an absolute criterion for exclusion of donors. A calculated graft to recipient body weight ratio of 0.8% is adequate for right lobe living donor liver transplantation.

A study was made of 19 adults with situs anomalies (situs inversus [n = 10], situs ambiguous with polysplenia [n = 8], situs ambiguous with asplenia [n = 1]). No patient had congenital heart disease, bowel obstruction related to malrotation, or immune deficiency disorders. All 10 patients with situs inversus had mirror-image location of the abdominal organs relative to situs solitus; nine had dextrocardia, and one had levocardia. The eight adults with situs ambiguous with polysplenia demonstrated a spectrum of abnormalities. All had some degree of abdominal heterotaxy, including midline livers and gallbladders (n = 5), right-sided stomachs and spleens (n = 3), and rotational abnormalities of the small bowel and colon (n = 7). Other findings included multiple spleens (n = 7), interruption of the inferior vena cava (IVC) with azygous or hemiazygous continuation (n = 7), truncation of the pancreas (n = 6), and ipsilateral location of the aorta and IVC (n = 1). In the one patient with asplenia, a midline liver, right-sided stomach, bowel rotation abnormality, IVC interruption, and pancreatic truncation were noted. Recognition of the spectrum of situs anomalies is important because the altered anatomy associated with these anomalies may result in confusing imaging findings when seen in conjunction with acquired diseases.

The cystic duct can be depicted with a variety of imaging modalities but is optimally visualized with direct cholangiography or magnetic resonance cholangiopancreatography. Nevertheless, unrecognized anatomic variants of the cystic duct may cause confusion on imaging studies and complicate subsequent surgical, endoscopic, and percutaneous procedures. Primary entities involving the cystic duct include calculous disease, Mirizzi syndrome, cystic duct-duodenal fistula, biliary obstruction, neoplasia, and primary sclerosing cholangitis. The cystic duct may also be secondarily involved by adjacent malignant or inflammatory processes. Postoperative alterations are seen after liver transplantation or cholecystectomy when a portion of the cystic duct is left behind as a remnant. Recognized postoperative complications include retained cystic duct stones, cystic duct leakage, and malposition of T tubes in the remnant. Pitfalls encountered in cystic duct imaging include pseudocalculous defects from overlap of the cystic duct and common bile duct, underfilling of the cystic duct during direct cholangiography, and admixture defects at the cystic duct orifice. Pseudomass or pseudotumor defects may result from an impacted cystic duct stone or from a tortuous, redundant cystic duct. Familiarity with the imaging appearance of the normal cystic duct, its anatomic variants, and related disease processes facilitates accurate diagnosis and helps avoid misinterpretation.

Half-Fourier RARE MRCP enables accurate evaluation of pancreaticobiliary disease and obviates ERCP in some patients.

MR cholangiography enables accurate detection and localization of PSC.

After treatment of cervical carcinoma, recurrent disease may be observed in multiple sites at imaging. Both typical and atypical manifestations of recurrent disease occur. Typical manifestations of recurrent cervical carcinoma involve the pelvis and lymph nodes. Pelvic recurrences may be observed as masses involving the cervix and uterus, vagina or vaginal cuff, parametria, bladder, ureters, rectum, or ovaries and may result in fistula formation or hydronephrosis. Nodal recurrence may be identified as enlarged pelvic and retroperitoneal nodes. Atypical manifestations of recurrent cervical carcinoma are being recognized with greater frequency due to the use of intensive pelvic radiation therapy, the evolution of improved imaging techniques, and the more frequent use of imaging as a means of surveillance. These atypical manifestations may involve the solid organs of the abdomen (focal masses) as well as the peritoneum, mesentery, and omentum (implants); gastrointestinal tract (obstruction, fistula formation, ischemia); chest (metastases to the lung parenchyma, pleura, and pericardium); bones (destructive lesions); and other sites. Familiarity with the imaging features of recurrent cervical carcinoma in these anatomic locations will facilitate prompt, accurate diagnosis and treatment.

MR cholangiography enables accurate depiction of the biliary tract and detection of biliary complications in patients with an orthotopic liver transplant.

MRCP enables noninvasive detection and exclusion of pancreatic duct trauma and pancreas-specific complications and provides information that may be used to guide management decisions.