Is there a future role for immunoscintigraphy in the diagnosis of colorectal carcinoma?

Immunoscintigraphy combines the advances in immunology and nuclear medicine to target tumor sites. Visualization of colorectal carcinomas is based on different monoclonal antibodies and their fragments against tumor-associated antigens labeled with gamma emitting radionuclides which accumulate in the tumor tissue due to their interaction with corresponding antigens. Available data on the role of immunoscintigraphy in detection of recurrence and metastases of colorectal carcinomas are reviewed. Despite a variety of investigations related to the application of immunoscintigraphy in diagnostics of colorectal cancer, using different radiolabeled immunoreactive agents and imaging methods there has not been a consensus among the investigators regarding the best modality of the method, including the specific radiopharmaceutical for this purpose. Some general conclusions concerning potentials of immunoscintigraphy in such diagnostics, including expectancy of the newly developed SPECT/CT systems, are suggested. The possibilities of PET imaging of colorectal carcinomas using monoclonal antibodies labeled with positron emitting radionuclides, as well as of the radioimmunoguided surgery and radioimmunotherapy are also discussed. Key words: Immunoscintigraphy, colorectal cancer, recurrences, metastases, radioimmunoguided surgery, SPECT/CT.

Relationship between enterogastric reflux estimated by scintigraphy and the presence of Helicobacter pylori.

The aim of the study is assessment of the relationship between enterogastric reflux and the presence of Helicobacter pylori infection as factors that cause gastritis, peptic ulcer and adenocarcinoma ventriculi. The study was performed in 52 patients with different digestive disorders, using gamma camera, during 90 min (1 frame/min) after intravenous injection of 185 MBq 99mTc-dietil IDA in the cubital vein. According to time/activity curves from the region of hepatobiliary system and stomach, index of enterogastric reflux (EGR) was assessed. There was no correlation between the presence of Helicobacter pylori and EGR (r = 0.181, df = 52, p > 0.05). However, Helicobacter pylori was present more frequently in the patients with positive EGR (p < 0.01), but there were no significant differences (p > 0.05) in reflux value in patients with either positive or negative findings of Helicobacter pylori.

Aortal aneurysm as a cause of ileus.

A 62-year-old patient presented with flatulence, abdominal distension and other symptoms of ileus. Roentgenographic finding found compression on duodenum. Blood pool scintigraphy ((99m)Tc erythrocytes) showed aortal aneurysm, while simultaneous gastric emptying study with liquid meal ((99m)Tc-S-colloid) showed dislocation of duodenum and compression from abdominal aortal aneurysm.

14C-urea breath test in the detection of Helicobacter pylori infection.

Helicobacter pylori infection is supposed to be one of the major causes of digestive and other diseases. Among a lot of invasive and non-invasive methods for its detection, none is ideal. The aim is an assessment of the Helicobacter pylori infection in the stomach using breath test and comparison to other diagnostic methods, as well as following up the effects of therapy. In 17 patients with digestive discomfort, breath test, rapid urease test and histology were performed, while in 47 patients with proven HP infection the effect of therapy was followed up using breath test and clinical findings. Breath test was performed after per oral administration of the capsule of (14)C urea (37 kBq). Findings of the breath and urease tests were in accordance in 14/17 patients (83%) while breath test and histology in 16/17 patients (94%). During follow-up of the therapeutic effects, breath test and clinical findings were in accordance in 43/47 patients (98%). Breath test can be useful in diagnosis but is a method of choice in following up the patients after therapy for H. pylori infection, because it is non-invasive, fast and precise.

Estimation of the relative liver perfusion using two methods of radionuclide angiography in the patients with hemodynamic disorders in the portal system.

The aim of this study is the assessment of the relative arterial and venous contribution to the total liver blood flow (hepatic perfusion index-HPI), with two methods (S1 and S2), and estimation of their value. With this correction, HPI nonsignificantly increases (p>0.05) in all the groups of patients, with a very high correlation between the HPI (S1) and HPI (S2) values (p<0.01). In comparison to the portal perfusion in controls, values were significantly (p<0.01) lower in chronic active hepatitis and liver cirrhosis and differed between themselves (p<0.01). In the groups of cirrhotic patients with esophageal varices, sclerosated esophageal varices, recanalized umbilical vein, portal thrombosis and cavernous portal vein, portal perfusion was lower (p<0.01) than in controls, chronic active hepatitis and liver cirrhosis without collaterals. Both angioscintigraphic methods are useful for the estimation of the disturbances in the portal system. Because of the more exact estimation of the liver perfusion, S2 is recommended.

[Evaluation of hepatic and portal blood flow component with radionuclide angiography]. / Procena radionuklidnom angiografijom arterijske i venske komponente protoka krvi kroz jetru.

Hepatic radionuclide angiography was performed with Gamma camera, after bolus injection of 740 MBq 99m-Tc-pertechnetate. Hepatic and portal phases (slopes) of the liver time-activity curve were separated at the moment of the maximal left kidney activity, and hepatic perfusion index (HPI) was determined. Decreased (p < 0.01) HPI values were observed in patients with liver cirrhosis with or without oesophageal varices (X + SD) (0.32 +/- 0.19 vs. 0.49 +/- 0.13 respectively) in comparison to the controls (0.68 +/- 0.06). HPI values in these two groups of patients also differ between themselves (p < 0.01). HPI values in patients with haemangiomas (0.64 +/- 0.08) were within normal range, pointing out the missing of haemodynamic alterations in the blood inflow through the portal-hepatic system. On the contrary, in patients with metastases of abdominal carcinomas, HPI was lower (0.40 +/- 0.28, p < 0.05) than in controls and patients with haemangiomas. Hepatic radionuclide angiography is a usefull method in the estimation of relative liver perfusion in patients with portal hypertension and liver tumours.