A quantitative radionuclide technique for investigating the lymphatic system with particular reference to lymphoedema

Stewart, Gordon (1985) A quantitative radionuclide technique for investigating the lymphatic system with particular reference to lymphoedema. MD thesis, University of Glasgow.

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Abstract

Chronic swelling of the lower limb presents a special diagnostic challenge. When the phlebograph is normal lymphography may be very helpful, but it is invasive, technically difficult and does not provide quantitative dynamic information about lymphatic function. This thesis describes the development of an alternative method to lymphography for investigating the lymphatic system by examining the clearance from the interstitial space of large molecules labelled with radionuclides. Two methods of investigating the lymphatic system by radionuclides in patients with chronic lower limb oedema are described and their results compared. The second/revised technique proved to be more accurate than the first method with a greater sensitivity and specificity. The revised technique consisted of measuring the clearance of 99m Tc Rhenium sulphide colloid from the inter-digital space and its arrival in the ilio-inguinal lymph nodes 30 minutes, 1, 2 and 3 hours later using a gamma camera in patients with the clinical and radiological features of primary lymphoedema, venous oedema, a group of patients with miscellaneous causes of oedema and a control group. The serial images were assessed visually by an independent observer and measurement of lymph flow was carried out by calculating the percentage uptake of radioactivity in the ilio-inguinal nodes. Simple visual interpretation of the images following an inter-digital space injection will clearly differentiate between lymphoedema and other forms of lower limb swelling (sensitivity - 95%; specificity 100%); but does not provide quantitative physiological information about lymph flow in these limbs. Estimation of lymph flow by calculation of the percentage uptake of the radionuclide has, however, shown a difference in the flow of lymph from the periphery in the groups of limbs studied. The lymphoedematous limbs had a persistently lower percentage uptake of colloid throughout the three-hour study when compared to the percentage uptake of injected activity in the ilio-inguinal lymph nodes at half, 1, 2 and 3 hours in the normal limbs, those with venous oedema and those with miscellaneous oedema, the difference being more marked as time progressed. The degree to which lymph flow was reduced in the lymphoedematous limbs correlated with the clinical degree of severity of lymphoedema. The results suggest that most severe lymphoedemas have a marked degree of impairment of lymph transport, although colloid clearance from the periphery may also be severely diminished even when the degree of lymphoedema is mild. The 55 limbs with lymphoedema were subdivided by radiological appearance and calculation of the percentage uptake has shown that lymph flow was more severely impaired in the limbs with proximal lymphatic abnormalities. Furthermore, both visual interpretation and calculation of the uptake have detected hidden lymphatic deficiences in the clinically normal limb. There was a consistently increased uptake of colloid in the ilio-inguinal region of the limbs with venous disease. These findings provide further evidence that there is an increased flow of lymph in limbs with venous oedema. Calculation of the percentage uptake of the colloid of the limbs with miscellaneous oedemas showed only a slightly increased lymph flow when compared to normal limbs. However, the technique was clearly able to differentiate this group of limbs from the mild lymphoedemas for which they can often be clinically mistaken. This technique has clearly differentiated between lymphatic and other causes of chronic lower limb oedema. There were no false positives using the iner-digital space injection technique, although 3 scans of patients with lymphoedema were interpreted as normal, i. e. 3 false negatives. Calculation of the percentage uptake of the radiocolloid in these studies at 30 minutes, however, showed that they were below the range for the control limbs and, by definition, would be classified on the borderline of abnormality. Examination of the lymphatic system using this technique has certain advantages over lymphography. It is almost non-invasive, technically simple to perform and diagnostic. It has also provided pathophysiological information about lymph flow, not hitherto available. Its main disadvantage is the lack of anatomical definition of the lymphatics and the lymph nodes. The results presented in this thesis suggest that this technique provides a new and simplified method of investigating the lymphatic system in patients with chronic lower limb oedema reserving X-Ray lymphography for those patients with lymphoedema who are being considered for direct lymphatic surgery and in whom a high degree of anatomical information is required.

Item Type: Thesis (MD)
Qualification Level: Doctoral
Keywords: Medicine, Medical imaging, Biophysics
Date of Award: 1985
Depositing User: Enlighten Team
Unique ID: glathesis:1985-76578
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 19 Nov 2019 14:07
Last Modified: 19 Nov 2019 14:07
URI: http://theses.gla.ac.uk/id/eprint/76578

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