Portal circulation by technetium-99m pertechnetate per-rectal portal scintigraphy

Portal circulation in patients with chronic liver diseases was evaluated by [99mTc]pertechnetate per-rectal scintigraphy. Technetium-99m pertechnetate (10 mCi) was instilled into the upper rectum, and serial scintigrams were taken. Radioactivity curves for the liver and heart were then recorded sequentially. Through analysis of these curves, the per-rectal portal shunt index (Sl) was calculated for six healthy subjects and 228 patients, 59 with chronic hepatitis, seven with idiopathic portal hypertension, six with primary biliary cirrhosis, and 156 with cirrhosis. In the healthy subjects, the Sl was 1.9-5.2% (mean 4.1%). In hepatitis, the mean Sl was 7.1%, and in cirrhosis, 52.9%. The Sl was higher in cirrhotic patients with esophageal varices than in those without (p less than 0.001), and in cirrhotic patients with encephalopathy than in those without (p less than 0.01). For some patients with portal hypertension, portal collateral circulation could be depicted, and images of changes in the portal collateral circulation after vascular anastomosis were seen.     

Experimental study of per-rectal portal scintigraphy using 99mTc-EHIDA

We discovered that 99mTc-EHIDA commonly used for hepatobiliary scintigraphy could also be administered per-rectally, with adequate absorption and optimal visualization of the portal system. To evaluation its usefulness, we experimented on rabbits using the method. Portal scintigraphy with rectal administration of 99mTc-EHIDA, 123I-IMP and 99mTc-RBC were performed in normal rabbits and in extrahepatic portal shunt model rabbits. Images of the liver and thorax were obtained and shunt indices were calculated from the count values of liver and lung or heart. Then the shunt indices were compared with shunt rate derived from direct injection of 99mTc-MAA into inferior mesenteric vein. Correlation between shunt rate of 99mTc-MAA and shunt indices of 99mTc-RBC, 123I-IMP and 99mTc-EHIDA were 0.64, 0.75 and 0.78, respectively, with 99mTc-EHIDA having the most favourable results. We concluded that 99mTc-EHIDA per-rectal portal scintigraphy is a noninvasive, quantitative, inexpensive and simple method for evaluation of portal circulation system. Also, we think that this method would be applicable to human usage from our experience with normal volunteers.     

Usefulness of per-rectal portal scintigraphy with Tc-99m pertechnetate for galactosemia in infants

Gaiactosemia discovered by newborn screening is rarely caused by enzyme deficiency. It has recently been reported that among patients without enzyme deficiency portosystemic shunting may be a cause of galactosemia in some patients. We did per-rectal portal scintigraphy in patients with such galactosemia detected during screening of newborns to examine the usefulness of this method for the diagnosis of portosystemic shunts via the inferior mesenteric vein. The subjects were eight neonates with galactosemia without enzyme deficiency detected during screening. A solution containing technetium-99m pertechnetate was instilled into the rectum, and serial scintigrams were taken while radioactivity curves for the liver and heart were recorded sequentially. The per-rectal portal shunt index was determined by calculating the ratio for counts of the liver to counts for the heart integrated for 24 seconds immediately after the appearance of the liver time-activity curve. A portosystemic shunt was detected in both of the patients with a shunt index of 30% or more, but not in the six patients with a shunt index less than 30%. The blood galactose levels of these six patients later entered the reference range. This method is noninvasive and there is little exposure to the radionuclide. It seemed to be useful for the diagnosis of portosystemic shunt in newborns with galactosemia without enzyme deficiency.     

Clinical need for both scintigraphy with technetium-99m GSA and per-rectal portal scintigraphy in some patients with chronic liver disease

Scintigraphy with 99mTc-diethylenetriaminepentaacetate with galactosyl human serum albumin (99mTc-GSA) and per-rectal portal scintigraphy are useful for evaluating hepatic functional reserve and portal circulation, respectively. We did the procedures simultaneously in some patients to examine the relationship between hepatic functional reserve and portal circulation in chronic liver disease. Scintigraphy with 99mTc-GSA was done in 10 healthy subjects, 45 patients with chronic hepatitis, and 165 patients with cirrhosis. Fifty-seven patients (13 with hepatitis and 44 with cirrhosis) also underwent per-rectal portal scintigraphy with 99mTc-pertechnetate within two weeks. A receptor index was calculated by dividing the radioactivity of the liver region of interest (ROI) by that of the liver-plus-heart ROI at 15 min after the injection of 99mTc-GSA. The index of blood clearance was calculated by dividing the radioactivity of the heart ROI at 15 min by that of the heart ROI at 3 min. A solution containing 99mTc-pertechnetate was instilled into the rectum, and serial scintigrams were taken while radioactivity curves for the liver and heart were recorded sequentially. A per-rectal portal shunt index was determined by calculating the ratio of counts for the liver to counts for the heart integrated for 24 seconds immediately after the appearance of the liver time-activity curve. The median receptor index was lower for more severe liver disorders, increasing in the order of chronic hepatitis, compensated cirrhosis and decompensated cirrhosis, and the median index of blood clearance was higher. The median receptor index was significantly lower when a complication (varices, ascites, or encephalopathy) was present, and the median index of blood clearance was higher. The shunt index was correlated significantly with the two other indices, but these values for some one-third of the patients disagreed in either indices. Scintigraphy with 99mTc-GSA and per-rectal portal scintigraphy with 99mTc-pertechnetate are both needed for accurate assessment of the severity of chronic liver disease before treatment-making decisions, because in some patients, results are not correlated.     

Evaluation of persistence of ductus venosus with Tc-99m DTPA galactosyl human serum albumin liver scintigraphy and I-123 iodoamphetamine per-rectal portal scintigraphy

Tc-99m DTPA galactosyl human serum albumin (Tc-99m GSA) hepatic scintigraphy was performed in two patients with patent ductus venosus before and after operation. To evaluate the portosystemic shunt flow, per-rectal portal scintigraphy with I-123 N-isopropyl-p-iodoamphetamine (IMP) was undergone in the same period. The portosystemic shunt indices (PSS index) were decreased from 67.9% to 7.3% in the patient 1, and from 77.3% to 22.7% in the patient 2, respectively. Quantitative indices of Tc-99m GSA hepatic scintigraphy improved dramatically in both patients. Under microscopic examination, nearly all the hepatic cells showed signs of severe fatty degeneration. After the operation, the severe fatty degeneration was alleviated and all the hepatic cells appeared normal. I-123 IMP per-rectal portal scintigraphy and Tc-99m GSA hepatic scintigraphy were useful in evaluating the quantitative shunt flow of the persistent ductus venosus and its hepatic functional reserve.     

Measurement of regional hepatic blood flow with 133Xe per-rectal portal scintigraphy

The hepatic blood flow (HBF) of patients with liver disease was measured by per-rectal portal scintigraphy with the use of 133Xe. To analyze the time-activity curves of the liver and portal vein, washout curves of the liver were plotted, and from those, the HBF and the ratio of the HBF of the right lobe of the liver to that of the left lobe (R/L ratio) were calculated. The HBF were 143 +/- 17 ml/100 g/min in 5 patients with chronic inactive hepatitis, 119 +/- 20 ml/100 g/min in 4 patients with chronic active hepatitis, and 73.2 +/- 23.4 ml/100 g/min in 7 patients with cirrhosis of the liver. All of four patients whose HBF was under 100 ml/100 g/min and whose R/L ratio was under 1.0 had cirrhosis of the liver. Only one of the 9 patients whose HBF was over 100 ml/100 g/min and whose R/L ratio was over 1.0 had cirrhosis of the liver. The results suggested that per-rectal portal scintigraphy is a useful and noninvasive method to measure the hepatic blood flow.     

Measurement of hepatic blood flow by use of per-rectal portal scintigraphy with 133Xe.

A relatively noninvasive method is needed to evaluate the hepatic blood flow of patients with liver disease. We used per-rectal portal scintigraphy with 133Xe, and analysed the time-activity curves of the liver and portal vein. To do this, wash-out curves of the liver were plotted, and the hepatic blood flow and the ratio of the blood flow to the right lobe of the liver to that to the left lobe (R/L ratio) were calculated. The mean hepatic blood flow was 137 +/- 23 ml/100 g/min for four patients with fatty liver, 139 +/- 16 ml/100 g/min for seven patients with chronic persistent hepatitis, 120 +/- 15 ml/100 g/min for ten patients with chronic aggressive hepatitis, and 75 +/- 21 ml/100 g/min for 14 patients with cirrhosis. All seven patients with hepatic blood flow that was less than 100 ml/100 g/min and an R/L ratio less than 1.0 had cirrhosis. Only two of the 22 patients with hepatic blood flow that was greater than 100 ml/100 g/min and an R/L ratio greater than 1.0 had cirrhosis. Per-rectal portal scintigraphy can be used to measure the hepatic blood flow, but it was not useful for the diagnosis of fatty liver.     

The value of combined99mTc-Sn-colloid and99mTc-RBC scintigraphy in the evaluation of a wandering spleen

Wandering spleen is the term commonly applied to splenic hypermobility that results from laxity or maldevelopment of its suspensory ligaments. It comes to medical attention usually as an abdominal mass, or when the spleen undergoes torsion. Diagnosis on clinical grounds alone is rarely made, and ultrasonography, CT and MRI findings have no specific characteristics for this condition.^99mTc-labeled colloid taken up by the spleen may provide a specific diagnosis. We report a case of wandering spleen, in which the preoperative diagnosis was made on the basis of sequential liverspleen scintigraphy with^99mTc-Sn-colloid and blood-pool scintigraphy with^99mTc-RBC. This is a rare case, in which hypermobility was assessed by sequential^99mTc-Sn-colloid scintigraphy, and to our knowledge, is the first case in which^99mTc-RBC scintigraphy provided useful information on splenic blood volume and its location.     

Assessment of hepatic blood flow by PET with 15O water: correlation between per-rectal portal scintigraphy with 99Tc(m)-pertechnetate and scintigraphy with 99Tc(m)-GSA

We performed positron emission tomography with 15O water (H2(15)O) to measure hepatic arterial and portal blood flow. In addition, portal haemodynamics and hepatic functional reserve were measured by per-rectal portal scintigraphy and scintigraphy with galactosyl human serum albumin, respectively. We studied 15 patients who had cirrhosis of the liver with underlying viral infection. After the intravenous injection of H2(15)O, positron emission tomography was performed. Blood samples were obtained after beginning the emission scan. The blood samples and positron emission tomographic images were analysed to calculate the radioactivity in the blood and liver. One-compartment model analysis was used to estimate hepatic arterial and portal blood flow. Computer acquisition of gamma-camera data was started just before the injection of 99Tc(m)-galactosyl human serum albumin. A receptor index and an index of blood clearance were calculated on the basis of the radioactivity of the liver and heart. A 99Tc(m)-pertechnetate solution was instilled into the rectum; serial scintigrams were performed and radioactivity curves for the liver and heart were recorded sequentially. A per-rectal portal shunt index was calculated from the curves. Median portal blood flow was 80 ml x 100 g(-1) x min(-1), median hepatic arterial blood flow was 56 ml x 100 g(-1) x min(-1), and median total hepatic blood flow was 138 ml x 100 g(-1) x min(-1) in patients with cirrhosis. The correlations between portal blood flow and the Child-Turcotte classification score, portal shunt index and receptor index were all significant. Our results show that hepatic arterial and portal blood flow can be measured by positron emission tomography with H2(15)O non-invasively and physiologically. This technique may be useful in pathophysiological studies of liver disease.     

Measurement of portal systemic circulation by oral and per-rectal administration of I-123 iodoamphetamine

In an earlier study, we measured the portal circulation noninvasively by Tc-99m pertechnetate per-rectal portal scintigraphy. This method makes it possible to see the portal circulation and to diagnose portal hypertension from the images of the liver and heart. However, the method mainly reflects circulation from the inferior mesenteric vein, the contribution of which to the portal circulation is less than that of the superior mesenteric vein. Here, we devised capsules of I-123 iodoamphetamine (IMP) that dissolve when the pH changes to evaluate the portal circulation arising from the superior mesenteric vein. I-123 IMP enclosed in an enteric-coated capsule was prepared and given orally, just before I-123 IMP was injected into the rectum. The per-rectal portal shunt index (RSI) and oral portal shunt index (OSI) were calculated from the count of radioactivity of the liver and lungs. The RSI and OSI of patients with cirrhosis were both higher than those of the patients with chronic hepatitis. In individual patients, the RSI was higher than the OSI. This noninvasive method seemed to be useful in evaluation of the portal systemic circulation in chronic liver diseases.     

Delayed visualization of gallbladder with in vivo labeled Tc-99m-red blood cell scintigraphy for gastrointestinal bleeding

A case of a 78-year-old man with delayed visualization of the gallbladder during in vivo labeling for 99mTc-red blood cell scintigraphy for gastrointestinal bleeding is reported. The patient had several episodes of renal failure, melena, anemia, blood transfusion, and hemodialysis. The mechanism of this unusual phenomenon is not clear; however, excess binding of heme and 99mTc-pertechnetate caused by autohemolysis and oliguria are suggested to be the main factor in this phenomenon.     

Evaluation of gastrointestinal bleeding by red blood cells labeled in vivo with technetium-99m.

To determine the effectiveness of abdominal imaging with RBCs labeled in vivo with Tc-99m, for the detection of gastrointestinal (GI) bleeding, 28 control subjects and ten patients with suspected bleeding underwent scintigraphy at 0-24 hr after tracer injection. Colonic activity was noted in one of the controls within 3 hr of injection, and in five of ten controls at 24 hr, all of whom had initial gastric activity. Of the ten patients with suspected GI bleeding, eight had documented active bleeding; seven of these had positive scintigrams. Nasogastric (NG) suction markedly decreased the presence of initial gastric activity in the patients with active bleeding. With this blood-pool radiopharmaceutical, frequent imaging of the abdomen over 24 hr can be done to test active bleeding. Continuous NG suction is recommended to reduce accumulation of gastric activity. These results suggest that red blood cells labeled in vivo with Tc-99m provide a sensitive method of detecting active GI bleeding.     

123I-IMP per-rectal portal scintigraphy in a patent ductus venosus: a case report

Portosystemic shunt is most frequent in portal hypertension associated with hepatic cirrhosis, meanwhile there are uncommon cases which have congenital portosystemic shunt. Recently we have encountered a patient with ductus venosus definitely diagnosed by angiography. In this patient, we performed a portal scintigraphy with 123I-IMP per-rectal administration in order to evaluate the portosystemic circulation. At the early phase of the study, the scintigraphy showed only the pulmonary uptake of 123I-IMP, and the liver was not revealed. Such findings in congenital anomalous cases of portosystemic shunt without hepatic parenchymal damage like this case can be similar to those in cirrhotic patients. In conclusion, this method was useful in evaluation of the portosystemic circulation, and helpful in determining therapeutic procedures for portosystemic circulation disorders.     

Scintigraphic visualisation of extrahepatic portal circulation in patients with portal hypertension using 99mTc-tin-colloid and 99mTc-HIDA

Rapid dynamic sequential scintigraphy of the abdomen with 99mTc-tin-colloid and 99mTc-HIDA has been used to evaluate two patients with portal hypertension. 99mTc-tin-colloid was useful for visualisation of diliated vessels in the abdomen. Radionuclide hepatobiliary imaging was useful in such cases in evaluation of the hepatobiliary system.     

Gastrointestinal scintigraphy with 99mTc-DTPA labeled tablets in fed and fasting subjects

The in vitro and in vivo dissolution of a sustained release theophylline formulation labeled with 99mTc-diethyltriaminepentaacetic acid (DTPA) has been monitored in six subjects with a scintillation camera. The study was performed in fasting conditions and was repeated after ingestion of a standardized meal. Results showed that the presence of food in the stomach dramatically increased the oesoduodenal transit time of the tablet (74 +/- 27 min vs 352 +/- 77 min, P less than 0.001) but did not modify the biodisponibility of theophylline. This study is another example when scintigraphy can be of definite value in pharmacokinetics.