L. Hooghe

Presurgical localization of abnormal parathyroid glands using a single injection of technetium-99m methoxyisobutylisonitrile: Comparison of different techniques including factor analysis of dynamic structures

Single-tracer methoxyisobutylisonitrile (MIBI) imaging is considered to be a sensitive method for the localization of abnormal parathyroid glands. The aims of this study were to determine which of the analytical techniques described for this method — visual comparison of early (15-min) and late (120-min) images, use of time-activity curves (TACs) generated on regions of interest and factor analysis of dynamic structures (FADS) — corresponds best with surgical findings, and to ascertain the potential overall contribution of presurgical scintigraphy. Fifty-five patients were studied, 34 of whom presented with primary hyperparathyroidism (HPT) and 21 with secondary HPT. After a 925 MBq injection of technetium-99m MIBI, a 40-min dynamic acquisition was performed and static images were acquired at 5, 20, 40 and 120 min using a gamma camera equipped with a pinhole collimator. The dynamic series were submitted to FADS, an attractive non-operator-dependent technique, and TACs were generated on regions of interest after the visual comparison of early and 120-minute images (15′–120′). The presumed localizations of abnormal glands were compared with a sketch drawn by the surgeon. Sensitivity was defined as the percentage of truepositive localizations and was 84.4%, 74% and 65% in adenoma and 76%, 66.6% and 45% in hyperplasia for 15′–120′, FADS and TACs, respectively. Surgical accuracy, i.e. the percentage of patients accurately and completely described, was 72%, 56% and 59% in adenoma and 53%, 30% and 22% in hyperplasia for 15′–120′, FADS and TACs, respectively. The visual comparison method scored best in all cases. FADS was found to be sensitive in cases of adenoma but was handicapped by more false-positive localizations. TACs were particular inefficient in hyperplasia. With respect to the detection of adenomas, we found a relationship between the gland weight and scintigraphic positivity. This dependence on gland weight was not found in hyperplasia. The poorer results obtained with all techniques for surgical accuracy can be explained by the need for a complete scintigraphic description of all pathological glands found by the surgeon in a patient. This study demonstrates that the 15′–120′ visual comparison method is more efficient and less cumbersome than TAC or the attractive FADS technique. However, it was less efficient than neck exploration by an experienced surgeon. Therefore, in our institution, scintigraphic studies are now only requested in selected cases of HPT, usually primary HPT and cases undergoing re-operation.

Impact of growth hormone treatment on a Belgianpopulation of short children with renal allografts

We retrospectively analyzed the effects of recombinant human growth hormone (rhGH) in a Belgian population of 36 short children with renal allografts. Seven children were dropped from the growth study: 1 had skeletal dysplasia and in 6 cases rhGH was given for less than 1 yr (1 died, 1 developed genu valgum, 2 were non-compliant and 2 grafts deteriorated). Final height was reached in 17 patients, and 12 children were still growing at the end of the study. Median height standard deviation score (SDS) in the 29 patients was -2.3 at the time of transplantation, and -2.7 when rhGH therapy was initiated. During rhGH therapy (median duration 3.2 yr, range 0.6-7.7 yr), height SDS increased by a mean of 0.4 per year, and bone maturation was not accelerated. Final height reached was 162.7 (149.0-169.5) cm (median SDS -1.8) in males and 151.0 (130.5-169.5) cm (median SDS -1.9) in females. Final height is significantly greater in males than females compared with a historical control group of untreated patients. Final height is within the parental target height range in 6 out of the 17 patients. The increase in height SDS in patients who were at an advanced stage of puberty (Tanner stages 4-5) when rhGH therapy was initiated exceeded our expectations (mean height gain 14.2 cm in boys and 10 cm in girls). In the cohort of 36 children, 4 patients developed an acute allograft rejection, all of whom had an underlying chronic rejection. This resulted in 3 graft losses within 5 yr. Our results indicate that rhGH treatment has a positive effect in short children with renal allografts, even if it is started in late puberty. In the presence of underlying chronic rejection, rhGH treatment needs careful monitoring to minimize the risk of graft loss.