In staging neuroblastomas, the demonstration of tumoural invasion of the bone marrow is an important criterion with regard to the therapeutic prospects and the prognosis. Iliac crest aspiration sampling has been used routinely for the detection of bone marrow metastases in neuroblastoma. However, due to the limited character of the sampling, it sometimes leads to false-negative results. Another procedure which is used to determine the extent of neuroblastoma is metaiodobenzylguanidine (mIBG) scintigraphy. In order to establish the respective merits of both diagnostic techniques retrospectively, 148 iodine-123 mIBG scans of 26 children with neuroblastoma have been re-evaluated and compared with the results of routine bone marrow samples obtained within a 4-week period before or after scanning. Three types of mIBG uptake in the bone/bone marrow could be differentiated: (1) no visualization of the skeleton; (2) diffuse uptake in the skeleton with or without focally increased uptake, which indicates massive, diffuse bone marrow invasion by the tumour; and (3) focal tracer accumulation in one or several bones. No tracer uptake was observed in the skeleton in 91 scans. In 89 of the 91 the bone marrow biopsy was negative. Twenty-four scans showed diffuse skeletal uptake with or without foci. The bone marrow biopsies were negative for eight of those 24 scans. Hyperactive foci in one or more bones without diffuse tracer accumulation in the skeleton were detected in 33 scans. In only 7 of these 33 scans did bone marrow biopsy specimens from the iliac MDP crest contain neuroblastoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Tumour uptake of 13N-labelled ammonia was studied by means of positron emission computerised axial tomography in 46 patients with various extensive neoplastic conditions. Eleven of the patients have been followed sequentially before, during and after radio- and/or chemotherapeutic treatment. Substantial accumulation of 13NH3 (up to five times the amount found in comparable normal tissues) was noted in some cases of breast cancer and their metastases, as well as in soft tissue sarcomas, in malignant neck nodes secondary to head and neck tumours, in lung tumours and their metastases, in melanomas, in malignant lymphomas, in metastasis prostatic carcinoma and in the case of ovarian carcinoma examined. Little or no extra uptake of 13NH3 was found ion necrotic or non-malignant tumours or in primary brain tumours, or in some primary breast cancer which otherwise appeared well vascularized and actively growing. In those patients who were followed sequentially, 13NH3 uptake could be seen to decrease with tumour regression. However, during the course of a radiotherapeutic treatment a transitory increase of 13NH3 uptake could be observed. If the therapy had not been successful, 13NH3 uptake was found to persist after treatment. Uptake of 13NH3 in tumours is to be regarded as the result of a complex interaction of both circulatory and metabolic influences. Studies using more specific tracers of flow and tissue metabolism will probably help to unravel the contributory physiological components.

Rapid sequence scintigraphy was used to study testicular arterial perfusion and venous stasis in 53 patients with varicocele-associated infertility, 17 with idiopathic testicular failure and 9 treated for varicocele. Arterial blood supply to the diseased testicle was decreased in 63 per cent of the patients with subclinical or low grade varicocele compared to 18 per cent with idiopathic testicular failure. In the majority of cases the disturbance of perfusion disappeared immediately after interruption of retrograde blood flow in the internal spermatic vein by transcatheter embolization, whereas persistently impaired perfusion was found in a few cases with no improvement of semen quality after treatment. Venous stasis was found in only 18 per cent of the patients with low grade varicocele compared to 88 per cent with large varicoceles. It is suggested that impaired arterial blood supply rather than venous stasis is the pathogenic factor in epididymo-testicular dysfunction associated with low grade varicocele.

Neuroblastoma (NB) tumour cells have a remarkable tendency to differentiate spontaneously or under the influence of certain drugs. It is not clear whether metaiodobenzylguanidine (MIBG) uptake correlates with differentiation of NB cells. In 28 tumours of 26 patients, iodine-123 MIBG uptake in primary NBs was studied in relation to tumour differentiation, tumour size, cell density and degree of necrosis in subsequently resected specimens. Genetic features such as the presence of chromosomal aberrations (1p-deletion and MYCN amplification) and/or P-glycoprotein (mdr-1 gene product) were also evaluated in relation to MIBG uptake. A highly variable and unpredictable intensity of MIBG uptake was observed in primary as well as secondary resected tumours. This intensity did not relate to any of the above-mentioned factors except that there was a trend towards more intense uptake with increasing size of the tumour. We conclude from our observations that, in contrast to commonly held opinion, well-differentiated tumours do not a priori show a lower MIBG uptake in vivo, even when there are a low number of viable cells and a high degree of necrosis. The degree of differentiation or tumour viability and necrosis following longstanding chemotherapeutic treatment cannot be predicted by the MIBG scan findings. The observed MIBG uptake may be importantly influenced by factors other than those associated with cellular differentiation.

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