| Popis: |
A semi-quantitative RNP using 99Technetium macroaggregated albumin for the evaluation and follow-up of DVT and CVI has been developed. Values were assigned to the deep veins of the calf, knee, tigh and pelvis based upon the localization and the characteristics of the images obtained: stasis, hot spots and collateral circulation. A maximum score of 18 reflected complete thrombosis of all 4 segments. 208 patients (mean age 53.7 years, range 18-92), 161 of whom had a proven risk factor for DVT were studied. 99Technetium was injected into the dorsal foot vein of 407 limbs with appropriate tourniquets and early and late imaging of the limbs, pelvis and lungs was performed. In 48 patients, 83 limbs, X-ray contrast phlebography (CP) was also done. The mean RNP score was 4.1 units (range 0.4-18) and higher in the left than the right lower limb. It was mostly high in patients with proximal recurrent DVT or in DVT superimposed on CVI. The score was easy to follow and helpful in the assessment of the extent of DVT. It was particularly helpful in 3 instances. 1) Assessment of venous patency following anticoagulant therapy. 2) Estimation of recurrent DVT. 3) Differentiation of recent DVT from venous insufficiency. Overall RNP method had a sensitivity of 87.6%, a specificity of 54% and an accuracy of 64.8%. The sensitivity was similar in above & below-knee thrombi. Yet the specificity was higher in above-knee thrombi. The highest accuracy (87.3%) was observed in pelvic and groin thrombi. The distribution of thrombi on CP was 19% below the knee, 31% above it and 50% both above and below the knee. Pulmonary embolism (PE) was initially observed in 54 patients (26%) with no clinical evidence of DVT and therefore untreated. This high level is most probably related to the high incidence of proximal DVT in the patients. 181 patients were treated with heparin & coumadin and the RNP score was decreased to 3.6 units (range 0.4-8.8). PE occurred during treatment in 11 (6.1%) and recurrent DVT in 16 (8.8%) patients. CVI was observed in 23 patients before treatment and in another 24 patients (13.2%) after treatment. These results indicate that the RNP method is a simple, semi-quantitative and useful technique for the evaluation and follow-up of DVT and CVI. It is most helpful in the assessment of the extent of DVT. It is also a rapid, noninvasive and cost effective techniaue. |
