N. Leners

Indium-111 Leucocyte Scanning in the Evaluation of Painful Hip Arthroplasty

Thirty patients with a painful hip arthroplasty had an In-111 leucocyte scan before surgical reexploration. In 12 patients, the In-111 leucocyte scan was abnormal and in all of them, microorganisms were found at the culture of the material from their hips at the operation. Among the 18 patients with a normal scan no infection was found in 17. In one patient, a thick-walled abscess growing Escherichia coli was found. We conclude that In-111 scanning is sensitive, specific and therefore useful in the differential diagnosis of pain after hip arthroplasty.

Quantitative Assessment of Erythropoiesis in Bone-marrow Expansion Areas Using Fe-52

Summary. Quantitative 52Fe scans were performed in 180 patients. Expansion of bone marrow was observed in 70. This bone marrow expansion was a nearly constant feature in haemolytic anaemia and in sideroblastic anaemia. It occurred in a third of the patients with myelofibrosis. In patients with polycythaemia rubra vera, expansion was noticed in only two out of seven. Erythropoiesis in expansion areas occurred despite persistence of fat in the iliac crest bone marrow biopsy. It could exist with a slight increase in erythropoiesis and might develop only after a long period of erythropoietic stimulation.Increased marrow activity can take place without erythropoietic expansion in long bones. The fraction of iron uptake in expansion areas did not exceed a third of total marrow iron uptake. With increasing erythropoiesis, the increase in iron uptake in expansion areas was less marked than the increase in the central areas. Erythropoiesis in expansion areas was usually not of major quantitative importance but could nevertheless reach the erythropoiesis of a normal adult.

Diagnosis of heterotopic bone marrow in the mediastinum using 52Fe and positron emission tomography

A patient with hereditary spherocytosis was admitted with mediastinal masses on the chest X-ray.52Fe and positron emission tomography (PET) showed uptake of52Fe in the masses and established the diagnosis of thoracic extramedullary hematopoiesis.

Scintigraphic evaluation of the haemopoietic bone marrow using a 99mTc-anti-granulocyte antibody: a validation study with 52Fe.

To specify the validity of bone marrow scanning using a monoclonal anti‐granulocyte antibody labelled with 99mTc (BW 250/183) for the functional assessment of haemopoiesis, we compared this method with 52Fe scan in 16 patients with haematological disorders. The examinations were performed using a rectilinear whole‐body scanner and the distribution of the two tracers was assessed visually and quantitatively in anatomical bone marrow segments, the spleen and liver. Qualitative comparison showed concordance in the bone marrow distribution of the two tracers in 83% of the segments. Discrepancies were found in six patients with hypoplastic or aplastic marrow. The spleen was visualized in all cases with the 99mTc‐Moab, including nine patients without splenic haemopoiesis (i.e. without spleen uptake of 52Fe). The uptake of the two tracers, quantified in bone marrow segments and the spleen, correlated well (PO‐0001), but not in the liver (NS). The correlation between the uptake values for each patient was excellent, except in cases of aplastic bone marrow. In conclusion, bone marrow scanning using a 99mTc labelled anti‐granulocyte monoclonal antibody enables functional evaluation of the distribution of haemopoiesis. Limitations include the evaluation of bone marrow aplasia and identification of splenic haemopoiesis, for which 52Fe remains the tracer of choice.

99mTc-labelled immunoglobulin scintigraphy in arthritis: an analysis of synovial fluid activity.

The distribution of 99mTc-labelled human polyclonal non-specific immunoglobulin G (HIG) in the synovial fluid was studied in 14 patients with rheumatoid and non-rheumatoid arthritides. Analysis included the determination of the total activity per ml synovial fluid 6 h post-injection (p.i.) of the tracer as well as of the protein- and cell-bound fractions. At 6 h p.i., > 60% of the injected dose remained in plasma as protein-bound radioactivity. Values in the synovial fluid ranged between 0.001 and 0.009% of the injected dose per ml. Importantly, the synovial fluid to plasma ratio was consistently < 1 (range: 0.09-0.43), which is in the range of ratios observed for endogenous proteins in vivo. Similar values were obtained in samples of synovial tissue obtained at surgery in two patients. These data are consistent with the hypothesis that labelled HIG accumulates in the extracellular fluid (both within the synovial tissue and fluid) by non-specific mechanisms (such as increased blood pool and capillary permeability) and does not equilibrate with circulating plasma proteins in accordance with basic knowledge of synovial physiology. In addition, it was found that most of the activity remained bound to the proteins in the fluid and that cell-binding occurred to a very low degree that cannot be considered an important mechanism of uptake of this radiolabelled agent in vivo. These results provide the first evidence in an in vivo human setting that radiolabelled HIG accumulates mainly by non-specific mechanisms in inflamed joints.

Uptake of In-111 pentetreotide by pleural plaques.

Somatostatin receptor imaging with In-111 pentetreotide has been validated for the diagnosis and staging of chest tumors with neuroendocrine differentiation such as bronchial carcinoid and small cell lung cancer. In-111 pentetreotide uptake is not specific for neuroendocrine tumors because somatostatin receptors are also expressed by white blood cells, leading to the in vivo visualization sites of infection sites or active inflammation. Pleural plaques may be due to asbestos exposure or tuberculosis. Presented here are three cases of In-111 pentetreotide uptake in pleural plaques. This uptake by benign lesions may be misleading in the diagnostic work-up of patients with lung tumors.

The spleen and haemolysis: evaluation of the intrasplenic transit time.

The mean intrasplenic red cell transit time (STT) and the slow mixing splenic red cell volume (SSV) have been measured in patients with hereditary spherocytosis (HS), autoimmune haemolytic anaemia (AIHA) and lymphoproliferative disease (LD). There was an inverse relationship between the mean red cell life span (MRCLS) and the STT in HS (r=–0·96, P<0·001) and in AIHA (r=–0·90, P<0·001). No such relationship existed in LD. The size of the spleen and the SSV were not related to the severity of haemolysis. Our data offer strong evidence for the conditioning effect of the spleen on HS‐ and AIHA red cells and suggest that the STT is an index of the adverse effect of the spleen on red cells in patients with HS or AIHA.

Additional myeloablation with 52Fe before bone marrow transplantation

For many hematological malignancies, high-dose chemoradiotherapy followed by bone marrow transplantation offers the best and sometimes the only chance for cure. However, the main causes of failure of this therapy are relapse and toxicity. In order to selectively deliver higher doses of radiotherapy to the bone marrow and to spare normal organs, we explored 52Fe therapy before a conventional BMT conditioning regimen. Twenty-four patients at high risk for relapse after BMT were included in a phase II study. The median follow-up was 42 months. The median 52Fe dose was 59 mCi. This resulted in a median radiation-absorbed dose (RAD) to the BM of 626 rad. The median RAD to the liver was 338 rad. No untoward effects were noted after the injections of 52Fe. The patients recovered hematopoiesis without toxicity in excess of that expected with conventional conditioning alone. The 3-year DFS probability was 49% (95% CI: 20–78%). Eight patients have relapsed, three of them in extramedullary sites. 52Fe should provide a way to boost the radiation dose to marrow-based diseases before bone marrow transplantation without excessive toxicity.

Evaluation of two 111In-oxinate formulations for labelling of white blood cells.

This study compares the cell labelling characteristics of two 111In-oxinate formulations. The two preparations differ by the solubilizing agent of the chelate and the total amount of oxine. White blood cell suspensions were obtained by standard separation techniques and were labelled with either of these formulations. The labelling efficiency was higher for 111In-oxinate in aqueous solution (compound B) compared to the preparation where an organic solubilizer was added (compound A) (79.2 +/- 7.7 vs 68.6 +/- 17.6%, respectively, P = 0.03). Red blood cells contaminating the cell suspensions incorporated a higher fraction of 111In if the cells were incubated with the aqueous 111In-oxinate preparation (22.6 +/- 4.6 vs 4.8 +/- 4.6%, respectively, P less than 0.0001). The uptake of activity by polymorphonuclear cells was reduced with compound B (46.1 +/- 12.8 vs 63.8 +/- 15.8%, respectively, P = 0.0002) whereas the fraction retained by mononuclear cells and platelets was similar (31.3 +/- 13.9 vs 31.4 +/- 15.0%, respectively). The recovery from the vial was higher for 111In-oxinate in an organic solution (86.6 +/- 1.82 vs 60.3 +/- 14.3%, respectively, P less than 0.0001). Twenty four hours after administration of the labelled cells, the vascular compartment was less frequently visualized if cells were labelled with compound A (8% of the scintigrams vs 62.5% respectively, P less than 0.0001). High quality images were more often recorded after the administration of cells labelled with compound A (60.0% of the images vs 23.5%, respectively, P less than 0.02). The image quality of scintigrams was not related to any of the other cell labelling parameters.(ABSTRACT TRUNCATED AT 250 WORDS)