Magnetic resonance and retrograde endoscopic cholangiopancreatography-based identification of biliary tree variants: are there type-related variabilities among the Saudi population?

PURPOSE: This study investigated biliary tree patterns in a Saudi Arabian population to identify common anatomical variations to establish a common ground for improved surgical practice and to avoid unexpected complications. We consider this type of investigation clinically important because the findings are valuable for pre-surgical planning in a broad range of procedures, including laparoscopic cholecystectomy and liver transplantation. METHODS: We conducted an imaging-based retrospective cross-sectional study involving 150 patients who underwent endoscopic retrograde cholangiopancreatography and magnetic resonance cholangiopancreatography for different indications at King Fahd Hospital of the University between January 2011 and December 2014. RESULTS: Typical right hepatic duct (RHD) tributaries were observed in 56% of patients and typical left hepatic duct (LHD) anatomy was detected in 81.4% of patients. The typical anatomical pattern for the cystic duct was found in 72% of patients. CONCLUSIONS: Our findings showed that types A1 and A3b were the two most common variations in the RHD, whereas those in LHD were types B1 (segment IV duct opens to the LHD), and B2 (segment IV duct opens to the common hepatic duct separately). Although the angular type was the most prevalent among cystic duct variations, there were many differences in the types of variations observed. The findings somewhat correlated with those of other studies, suggesting that the normal biliary tree anatomy is similar among the Saudi population and in other ethnic groups.

Gadolinium Retention after Contrast-Enhanced Magnetic Resonance Imaging: A Narratative Review.

Over the past five years, several studies have reported deposition and retention of gadolinium in the brain after administration of gadolinium-based contrast agents (GBCAs) during radiological procedures. Patients with renal insufficiency cannot filter gadolinium efficiently; however, gadolinium is also retained in the brain of some adults and pediatrics with no renal impairment. In the literature, data is mostly available from retrospective magnetic resonance imaging (MRI) studies, where gadolinium deposition may be indirectly measured by evaluating changes in T1 signal intensity in the brain tissues, particularly in the deep gray matter such as the dentate nucleus and/or globus pallidus. Many pathological studies have reported a direct correlation between T1 signal changes and gadolinium deposition in human and animal autopsy specimens, which raised concerns on the use of GBCAs, particularly with linear chelators. The association between gadolinium accumulation and occurrence of physical and neurological side effects or neurotoxic damage has not yet been conclusively demonstrated. Studies have also observed that gadolinium is deposited in the extracranial tissues, such as the liver, skin, and bone, of patients with normal kidney function. This narrative review describes the effects of different types of GBCAs in relation to gadolinium deposition, evaluates current evidence on gadolinium deposition in various tissues of the human body, and summarizes the current recommendations regarding the use of GBCAs.