Variations in normal hepatobiliary scintigraphy in Indian population.CB Bhatt, NB Kamdar, GH Tilve
Correspondence Address: Source of Support: None, Conflict of Interest: None PMID: 0002621662
Source of Support: None, Conflict of Interest: None
Hepatobiliary scintigraphy was performed with Tc99m iminodiacetic acid (IDA) analog, in 100 apparently healthy adults, to study the variations in the normal hepatobiliary scintigraphy. Gall bladder (GB) was visualised in 43% at 15 min; 87% at 30 min, 90% at 45 min and 99% at 60 min and the small intestine (SI) was visualised in 24% at 15 min, 69% at 30 min, 76% at 45 min and 92% at 60 min. Left hepatic duct was prominent in 45%. Reciprocal relation between SI and GB was observed in 21%.
Keywords: Adolescent, Adult, Biliary Tract Diseases, radionuclide imaging,Female, Human, Imino Acids, diagnostic use,India, ethnology,Liver Diseases, radionuclide imaging,Male, Middle Age,
Hepatobiliary imaging with Tc99m labelled iminodiacetic acid (IDA) analogs is useful as a simple non-invasive technique in the diagnosis of gall bladder disease,, in differential diagnosis of intra-hepatic and extra-hepatic jaundice, in biliary obstruction and other non-biliary disorders.,
The normal variations in hepatobiliary imaging with Tc99m-IDA often create diagnostic problems. For example, the late appearance of isotope in the small intestine may be a normal variant or may be due to partial obstruction in the biliary tree or a spastic Sphincter of Oddi More Details. We, therefore, studied the spectrum of variations in the normal appearance of the intra-hepatic segmental bile ducts, the gall bladder (GB), common bile duct and the appearance of the radio-pharmaceutical agent in the small intestine (SI).
A total of 100 adults (54 males, 46 females) ranging in age from 18 to 64 years (mean 31 years) were studied. Hepatobiliary scintigraphy was performed after an overnight fast with intravenous administration of 111-185 MBq (3-5 mCi) of mTc IDA (BULIDA). Serial supine abdominal scintigrams were obtained using Dyna-4 Picker gamma camera fitted with a low energy, all-purpose, parallel hole collimator. The spectrometer was set for 140 KeV with a 20% window. Images were taken on 8 x 10 inches X-ray film at 15 minutes intervals for 60 minutes. Following this, a fatty meal was given and images were obtained at 90, 120 and 180 minutes.
The time of appearance of tracer into the GB and SI were noted. The relative prominence of the right and left hepatic ducts was also determined.
Visualisation of the GB and the SI at 15, 30, 45 and 60 minutes was as shown in[Table - 1]. In the only subject in whom the GB was visualised at 120 min, the GB emptied after a fatty meal. In 8% the SI was visualised only after a fatty meal, given after 60 min.
The relative prominence of LHD and RHD is as shown in [Table - 2]
Non-visualisation of the ducts was associated with early intestinal activity. Similarly, in cases where the GB appeared after 30 min, there was early SI appearance, and vice versa. In the 13% in whom the GB appeared after 30 min, the SI was seen within 4-15 mins. Of the 31% of subjects in whom the SI was seen after 30 min, the GB was seen at 15 min, in 26% and in 5% before 30 min.
The Tc99m-IDA analogs have been in use in clinical practice since 1975; however, normal variations in hepatobiliary scintigraphy were not studied until nearly a decade later. A reciprocal relationship exists between the GB and the SI, depending upon the tone of sphincter of Oddi. Normally a major part of the bile flows into the GB and only 30% in to the SI. On the other hand, if the tone of the sphincter is low, bile flows into the St earlier than the appearance of the GB. This was seen in 13% of our subjects.
In subjects who have an increased tone of the sphincter of Oddi, all the bile flows into the GB. In such cases, on hepatobiliary scintigraphy, the radio-pharmaceutical will not enter the SI and all will thus be accumulated in the GB. However, after a fatty meal bile flows normally into the SI. Such a phenomenon suggests the absence of pathological obstruction to the bile flow; this was seen in 6% of our subjects, where the SI was not visualised till 60 min, but after a fatty meal all these subjects showed radiopharmaceutical in the SI.
In the study of Walter et al. 34% of subjects showed reciprocal relationship between the GB and the SI. In 8% the GB appeared after 30 min and the SI was seen in 25 min. Whereas in 26% the SI was seen after 30 min, the GB appeared in 25 min. This reciprocal relationship, as mentioned earlier, was seen in total 21% in our study.
Nearly one-half of our subjects (45%) showed a prominent LHD. Walter et al shown LHD prominence in 55% of his subjects. The reasons for this could include more anterior position of the LHD, thin liver tissue overlying the LHD, a larger length compared to the RHD with more tortuosities that impede free bile flow into the common hepatic duct and an anomalous drainage of the posterior or anterior segment duct of the right lobe into the LHD.
In conclusion, awareness of the variations in normal hepatobiliary scintigraphy, as described in our subjects, avoid pitfalls in diagnosis of biliary free obstruction or gall bladder diseases.
[Table - 1], [Table - 2]