when the gallbladder is not visualized in its normal location , the possibility of its ectopic location should be considered . a case of incidentally detected anomalous position of gall bladder causing confounding problem in interpretation of pet - ct is described .
a 70-year - old man , with h / o chronic liver disease and suspected of hepatocellular carcinoma [ serum alpha - fetoprotein ( afp ) 5024 ng / ml ] was subjected to fluorine-18 fluorodeoxyglucose positron emission tomography ( f-18 fdg pet)/computed tomography ( ct ) imaging .
rest of the liver revealed non - fdg avid lesions in segments iii and viii . on viewing the fused pet / ct images
, the radiotracer accumulation was localized to the anomalously placed suprahepatic gallbladder . magnetic resonance ( mr )
images of the same patient confirmed the presence of the suprahepatic gallbladder [ figure 1 ] .
( a ) transaxial view of pet image showing suprahepatic subdiaphragmatic gallbladder with tracer uptake ; ( b ) coronal view of pet image ; ( c ) sagittal view of pet image ; ( d ) transaxial view of ct image ; ( e ) coronal view of ct image ; ( f ) sagittal view of ct image ; ( g ) transaxial view of post - contrast t1-weighted mri image ; ( h ) coronal view of post - contrast t1-weighted mri image ; ( i ) transaxial view of t2 fat saturated mri image shows gallbladder as a bright structure
routine imaging of the gallbladder demonstrates a wide array of imaging variants , including anomalies in location , number , and configuration .
an awareness of these normal variants would prevent misdiagnosis and aid in the assessment of differential diagnostic possibilities . normally , the gallbladder is situated adjacent to the inferior surface of the liver , in the plane of the interlobar fissure , with the gallbladder neck maintaining a constant relationship to porta hepatis . the gallbladder is generally found in the right upper quadrant , but may be seen in other parts of the abdomen . while anomalous positions are rare , the most common of these are ( 1 ) under the left hepatic lobe , ( 2 ) intrahepatic , ( 3 ) transverse , and ( 4 ) retroplaced ( retrohepatic or retroperitoneal )
. the lesser common of these are ( 1 ) supradiaphragmatic and ( 2 ) suprahepatic .
gallbladder is intrahepatic during the embryonic period and becomes extrahepatic only later . an intrahepatic gallbladder ( usually a congenital anomaly )
this poses a problem for scintigraphy , as an intrahepatic gallbladder can cause a focal defect ( pseudo  space - occupying lesion ) ; ultrasonography can be helpful in these cases .
the suprahepatic region is among the rarest sites , and very few reports have appeared in either the surgical or radiological literature.[35 ] of the very few reports on the suprahepatic gallbladder , one refers to a normally inserted organ that rotated 180 upward to an intrathoracic position after eventration of the diaphragm . in two other cases ,
an abnormally mobile gallbladder was found trapped between the chest wall and the upper border of the liver ; this became symptomatic and caught the attention of the clinician and the imageologist .
faintuch et al . reported three cases of suprahepatic gallbladder with hypoplasia of the right hepatic lobe and upward migration of the gallbladder .
gansbeke reported a case of suprahepatic gallbladder which was associated with hepatomegaly due to macronodular cirrhosis complicating existing hepatitis .
kabaroudis reported a case of floating gallbladder associated with hypoplasia of the right hepatic lobe , whereas maeda had reported a similar case associated with hypoplasia of left hepatic lobe .
pet - ct is found to be useful in diagnosing this rare anatomical variant of ectopically located gall bladder and predicting its functional implication .
 the purpose of this study was to appraise the imageologists of a possible mislocalization of tracer accumulation to anomalously placed gallbladder during positron emission tomography - computed tomography ( pet / ct ) examination . 
 pet / ct is increasingly playing an important role in staging and restaging of the disease process in cancer patients . with the advent of fusion imaging 
 , the tracer accumulation can be correctly localized to a structure or lesion on ct . 
 we did a staging pet / ct scan of a patient with hepatocellular carcinoma for liver transplant evaluation . 
 fluorine-18 fluorodeoxyglucose ( f-18 fdg ) was used as a tracer and the scan was performed on seimens biograph - mct pet / ct machine . 
 we noted the tracer accumulation at the superior surface of liver , which was localized to the anomalously placed gallbladder in suprahepatic subdiaphragmatic location . 
 the anomalously placed gallbladder can create localization confusion . keeping the possibility of ectopically placed gallbladder in mind , 
 the imageologist can better localize the tracer uptake . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION