Platelet kinetics in patients with chronic immune thrombocytopaenia treated with thrombopoietin receptor agonists.

INTRODUCTION: Thrombopoietin receptor agonists (TPO-RAs) increase platelet counts (PC) in the majority of patients with chronic immune thrombocytopaenia (ITP). Platelet kinetics study (PKS) might contribute to the understanding of mechanisms that lead to durable response. OBJECTIVES: To evaluate the effects of TPO-RAs on PKS parameters in chronic ITP patients. METHODS: Fifteen chronic ITP patients, aged 59 years [range: 22-84], female/male: 10/5, splenectomised 7/15, were treated with TPO-RAs (eltrombopag/romiplostim: 11/4). Durable response was defined as PC ≥30 × 109 /L at 6 months. Autologous 111 Indium-oxinate PKS was performed before and 5 months after TPO-RAs initiation. Accordingly, platelet survival (PS), platelet turnover, production ratio and sequestration site were assessed. RESULTS: Durable response was achieved in 13/15 of patients (eltrombopag/romiplostim: 10/3). Pre-treatment parameters were: PC 10 × 109 /L [range: 1-110], PS 0.5 days [range: 0.1-1.7 (normal values: 7-10)], platelet turnover 30 857 Plt/µL/day [range: 944-103 500] and platelet production ratio 0.64 [range: 0.01-3.2 (normal values: 1 ± 0.2)]. Post-treatment assessment showed significantly higher: PC 92.5 × 109 /L [range: 28-260, p = .001], PS 2.2 days [range: 0.1-3.6, p = .008], platelet turnover 70 213 Plt/µL/day [range: 2800-462 236, p = .02] and platelet production ratio 1.8 [range: 0.5-37.9, p = .011] compared to the pre-treatment values. Platelet sequestration site altered in 3/15 treated with TPO-RAs. CONCLUSIONS: TPO-RAs could increase PC by simultaneous increasing of platelet production and decreasing of platelet destruction.

GammaKey system for improved diagnostics with gamma cameras.

We designed the GammaKey system for the acquisition, storage and analysis of images from semi-analogue gamma scintillation cameras (GSCs). The GammaKey system, operating on a standard PC, replicates the functionality of earlier dedicated computer systems, allows the exchange of data in the DICOM format and has an open architecture enabling the development of new diagnostic techniques. The main purpose of the GammaKey is to enable the continued use of old GSCs which have functional scintillation crystals, but also to permit data exchange with new digital GSCs. The GammaKey has been technically validated by standards established by the National Electrical Manufacturers Association. The GammaKey has been used for seven years in two leading centres for nuclear medicine in Serbia (the Clinical Center of Serbia, Belgrade, and the Clinical Center of Vojvodina, Novi Sad) in approximately 30,000 patients. Clinical application proves that the GammaKey is a robust and reliable system with high-quality image output. Data processing can be upgraded with non-standard features added on request as shown in two examples: (1) the testing of splenectomy efficacy in the case of thrombocytopenia with normal production; and (2) the detection and localisation of parathyroid adenomas.

Gallium-68 DOTATOC PET/CT in vivo characterization of somatostatin receptor expression in the prostate.

AIM: The aim was to investigate somatostatin receptor (sstr) expression in normal prostate by determining the maximum standardized uptake value (SUVmax) of (68)Ga-DOTATOC PET/CT in neuroendocrine tumor (NET) patients, without NET involvement of the prostate gland, for establishing the reference standard. METHODS: Sixty-four NET patients underwent (68)Ga-DOTATOC PET/CT. SUVmax of the prostate gland, normal liver, testes, and gluteus muscles were evaluated. The prostate gland size was measured. Statistical analysis was performed using dedicated software (SPSS13). RESULTS: Mean/median (68)Ga-DOTATOC SUVmax values were as follows: normal prostate 2.6 ± 0.0, slightly enlarged prostate 4.2 ± 1.6, prostatic hypertrophy 4.9 ± 1.6, prostatic hyperplasia 5.0 ± 1.5, prostate cancer 9.5 ± 2.1, normal liver 7.3 ± 1.8, testes 1.8 ± 0.5, and gluteus 1.0 ± 0.2. The normal prostate gland had three times less sstr expression than normal liver tissue. Strong correlation was found between patient age and sstr expression in prostate/prostate size. No significant difference existed in sstr expression between prostatic hypertrophy and hyperplasia. Much higher sstr expression was found in prostatic cancer compared with normal prostate. CONCLUSION: (68)Ga-DOTATOC PET/CT defines the baseline sstr uptake in prostate not affected by NET (significantly lower than in the liver). Higher values were established in prostatic hyperplasia and hypertrophy. Only concomitant prostate cancer was associated with higher SUVmax in comparison with non-neoplastic liver.

Intraoperative somatostatin receptor detection after peptide receptor radionuclide therapy with (177)Lu- and (90)Y-DOTATOC (tandem PRRNT) in a patient with a metastatic neuroendocrine tumor.

AIM: The aim of this chapter is to present the results of the first intraoperative somatostatin receptor detection after peptide receptor radionuclide therapy (PRRNT) with (90)Y- and (177)Lu-DOTATOC using a handheld gamma probe and comparison with the findings of preoperative (68)Ga-DOTATOC PET/CT in a patient with a metastatic neuroendocrine tumor (NET) of the ileum. MATERIALS AND METHODS: A 56-year-old female patient, treated twice by PRRNT, was admitted for the third cycle and subsequent surgery. Before operation, the following studies were performed for restaging after the second cycle of PRRNT: (99m)Tc-MAG3 + TER, (99m)Tc-DTPA + GFR, abdominal ultrasonography, MRI of the abdomen, (68)Ga-DOTATOC PET/CT as well as (18)F-fluoride PET/CT. Serum tumor markers were measured before and after PRRNT. Tandem PRRNT was performed using 3000 MBq (90)Y-DOTATOC and 6000 MBq (177)Lu-DOTATOC. Whole-body scintigrams were obtained at 23 and 43 h. Five days after PRRNT, the patient was operated using a handheld gamma probe. Immunohistochemistry and histopathology of the resected tissue were performed. RESULTS: Tandem PRRNT was very well tolerated by the patient. Before PRRNT, (68)Ga-DOTATOC PET/CT revealed the primary tumor in the ileocoecal region as well as bilobular liver metastases and a right iliac bone lesion (osteoblastic on (18)F-fluoride PET/CT). Compared with the previous findings, there was good therapy response (partial remission of the tumor lesions). No nephrotoxicity was observed. Serum chromogranin A (836 µg/l, n < 100) and serotonin (852 µg/l, n < 200) were strongly elevated. Posttherapy scans showed intense uptake in metastases and the primary tumor. Intraoperative gamma probe detected-in addition to the known lesions-bilateral ovarian metastases not visualized by (68)Ga-DOTATOC PET/CT. Bilateral adnexectomy, right hemicolectomy, excision of hepatic metastases in S3, and partial resection of peritoneum were performed. Histopathology confirmed metastases in both ovaries. CONCLUSIONS: Gamma probe-guided surgery after (177)Lu PRRNT is feasible and appears to be more sensitive than (68)Ga-DOTATOC PET/CT. This technique might aid the surgeon in achieving more complete tumor resection through intraoperative detection of very small lesions (<5 mm) directly after PRRNT.

One-year follow-up of myocardial perfusion and function evaluated by gated SPECT MIBI in patients with earlier myocardial infarction and chronic total occlusion.

OBJECTIVE: Optimal treatment for chronic total occlusion (CTO) in the infarct-related coronary artery is not clear. Our aim was to assess myocardial perfusion, left ventricular ejection fraction (EF), and left ventricular size using gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging with 99mTc-methoxy-isobutyl-isonitrile in patients with CTO before and 1 year after recanalization. METHODS: Thirty patients with earlier myocardial infarction and at least one CTO underwent percutaneous coronary intervention (PCI) as well as nitrate-enhanced gated SPECT myocardial perfusion and dobutamine stress echocardiography before and 11 +/- 1 months after recanalization. They were divided into three groups based on the outcome of the follow-up angiography: (i) successful recanalization with no evidence of in-stent restenosis (n=13); (ii) successful recanalization with in-stent restenosis (n=7) and (iii) unsuccessful recanalization (n=10). RESULTS: Overall success of recanalization for CTO was 74%. In group 1, myocardial viability was preserved in 11 of 13 (85%) patients at baseline. Gated SPECT at 1 year showed a significant decrease in perfusion abnormalities (29 +/- 12 to 23 +/- 14%, P < 0.05) and left ventricular end-diastolic volume (EDV) (168 +/- 47 to 151 +/- 47 ml, P < 0.05). Improvement in EF (51 +/- 11 to 54 +/- 13%, P > 0.05) and reduction in left ventricular end-systolic volume (ESV) (84 +/- 37 to 77 +/- 40 ml, P > 0.05) did not reach the level of significance. Myocardial viability was preserved in only two of seven patients (28%) in group 2. Neither mean perfusion abnormalities (37 +/- 24 to 35 +/- 22%, P > 0.05) nor global left ventricular parameters (EF 41 +/- 15 vs. 42 +/- 19%, EDV 298 +/- 33 vs. 299 +/- 57 mL, ESV 197 +/- 12 vs. 195 +/- 32 ml; P > 0.05) changed at the follow-up. In group 3, myocardial viability was preserved in seven of 10 patients (70%) at baseline, but no significant changes in perfusion (40 +/- 18 vs. 41 +/- 19%, P > 0.05) and left ventricular function (EF 42 +/- 17 vs. 44 +/- 14%, EDV 228 +/- 101 vs. 227 +/- 81 ml, ESV 143 +/- 87 vs. 146 +/- 8 ml; P > 0.05) were seen at the follow-up. CONCLUSION: Myocardial perfusion and EDV may significantly improve 1 year after PCI provided recanalization of CTO was successful. Our preliminary findings suggest that successful recanalization of CTO may have favorable outcome on left ventricular perfusion and function, particularly in patients with viable myocardium before PCI. The gated SPECT myocardial perfusion imaging with 99mTc-methoxy-isobutyl-isonitrile may be useful for monitoring long-term functional outcome of PCI in patients with CTO.

Site of myocardial infarction and severity of perfusion abnormalities impact on post-stress left ventricular function in patients with single-vessel disease: gated single-photon emission computed tomography methoxyisobutylisonitrile study.

OBJECTIVES: We used gated single-photon emission computed tomography methoxyisobutylisonitrile (SPECT MIBI) to (i) determine whether location of myocardial infarction (MI) and severity of perfusion abnormalities affect post-stress left ventricular function in patients with single-vessel coronary artery disease, and (ii) correlate changes between post-stress and rest ejection fraction (EF) with the severity of perfusion and regional wall motion abnormalities (RWMAs). METHODS: Eighty-eight patients with a history (> or =3 months) of anterior MI (n=45) or inferior MI (n=43) underwent a 2-day stress-rest gated SPECT MIBI. 4D-MSPECT software was used to calculate left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), EF, and the difference from post-stress to rest EF (EFs-EFr). Summed stress scores, summed rest scores, and summed difference scores (SDS) were calculated based on the 17-segment model. RWMAs were visually assessed using a 5-point score. RESULTS: Patients with anterior MI, compared with those with inferior MI, showed significantly greater perfusion abnormalities (summed stress score 11.0+/-5.5 vs. 7.5+/-2.4, P<0.01, summed rest score 7.4+/-4.7 vs. 5.2+/-1.9, P<0.01, SDS 3.3+/-1.0 vs. 1.9+/-1.0, P<0.05) and higher post-stress and rest RWMA (RWMSS 12.2+/-6.0 vs. 8.7+/-4.1, P<0.01, RWMRS 8.7+/-5.4 vs. 5.6+/-3.0, P<0.01). In 22 patients with anterior reversible ischemia in addition to fixed defect, post-stress and rest EDV and ESV were significantly larger and post-stress EF decreased more than in 21 patients with inferior MI (EDV 144.0+/-28.9 ml vs. 108.6+/-36.9 ml, ESV 70.6+/-22.2 ml vs. 53.4+/-20.5 ml, EFs-EFr -4.2+/-3.5% vs. -1.5+/-2.2%, P<0.01). SDS and RWMA were highly correlated with EFs-EFr. CONCLUSION: In patients with single-vessel coronary artery disease, the extent and severity of perfusion and RWMAs assessed by gated SPECT MIBI are greater after anterior MI than inferior MI. Global left ventricular function is significantly more affected after anterior MI only in patients with reversible ischemia in addition to fixed wall defect. Decrease in EF from post-stress to rest is closely associated with the severity of perfusion and RWMAs. Overall results suggest that the extent and severity of perfusion and RWMAs are more prominent in the myocardial region supplied by left anterior descending coronary artery than by right coronary artery, which may explain significantly worse post-stress left ventricular function after anterior MI.

Assessment of non-small cell lung cancer viability and necrosis with three radiopharmaceuticals.

UNLABELLED: Assessment of tumor viability and necrosis of non-small cell lung cancer and detection of distant metastases are important for diagnosis, staging, monitoring the response to treatment and planning long-term management. We performed scintigraphy on patients with non-small cell lung cancer to determine the utility of three tumor targeting tracers for diagnosing primary lung cancer, for differentiating viable from necrotic tumor tissue and for detecting distant bone and soft tissue metastases. Our patients were divided into groups. Group A consisted of 27 patients, 25 male and 2 female, mean age 59 years, range from 35 to 72 years. These patients underwent radioimmunoscintigraphy (RIS) using monoclonal antibody against human milk fat globule labeled with technetium-99m ((99m)Tc). Group B consisted of 23 patients, 21 male and 2 female, mean age 56 years, range: 37 to 70 years. Group C consisted of 24 patients, 20 male and 4 female, mean age 58 years, range: 35 to 74 years. Both Groups B and C underwent chest and whole-body scintigraphy with 555 MBq of (99m)Tc-sestamibi ((99m)Tc-S) and 111 MBq of thallium-201 chloride ((201)TlCl), respectively. Tumor to non-tumor ratio was calculated. Our findings show that RIS had 52% sensitivity in detecting primary non-small cell lung cancer. In contrast, the sensitivity of (99m)Tc-S and of (201)Tl scintigraphy was 87% and 88%, respectively. High uptake of all three radiopharmaceuticals was found in 6 patients with distant soft tissue and bone tissue metastases and in 1 patient with brain metastasis. Mean tumor to non-tumor ratios were similar: for RIS 1.7+/-0.4, for (99m)Tc-S 1.6+/-0.3 and for (201)Tl 1.6+/-0.2. IN CONCLUSION: (99m)Tc-S and (201)Tl scintigraphy are superior to RIS for detecting non-small primary lung cancers and potentially clinically useful methods for detecting primary lung cancer as above, as well as bone and soft tissue metastases.

[Methods for the quantification of left ventricular volumes assessed by radionuclide ventriculography (first part)].

The purpose of this study was to point out the existing methods and to describe and evaluate the accuracy of new, original, "Geometric-count-based" (GCB) method, based on radionuclide ventriculography, for the measurement of left ventricular volumes compaired to the contrast ventriculography. By having done this, the aim was to compare the accuracy of GCB method and other two radionuclide methods available for left ventricular volume measurements: Count-bases Massardo method and gated blood pool SPECT method. In GCB method count based data from radionuclide ventriculography were combined with geometric ones assuming a prolate ellipsoid left ventricular's shape with identical short axes. The following equation for computing left ventricular end-diastolic volume was developed: EDV = 2 x c x M x C(tot)/C(max), (1) where: 2c--manually drown short axis of prolate ellipsoid (left ventricle) at end-diastolic frame, M-calibrated pixel size, C(tot)--total counts in left ventricular's region of interest at end-diastolic frame, C(max)--maximum pixel counts in left ventricular's region of interest. Physical experiments with two different heart shaped phantoms were used to compare volumes assessed by all three radionuclide methods with the true volumes. The true volumes of cylindrical and ellipsoid phantoms of 112.5 ml and 190.5 ml, were computed to be 114 ml and 196 ml by our GCB method, 168 ml and 180 ml by Massardo method and 142 ml and 222 ml by gated blood pool SPECT methods, respectively. In clinical study, in 65 patients volumes assessed by radionuclide methods were compared to volumes measured using single plane contrast ventriculography as a gold standard. A good correlation of our original method was obtained with a contrast ventriculography for both EDV/m2 and ESV/m2 (r = 0.94, r = 0.92), slightly lower for Massardo method (EDV/m2: r = 0.90, ESV/m2 : r = 0.89) and significantly lower for gated blood pool SPECT (EDV/m2: r = 0.85, ESV/m2: r = 0.81, p < 0.01). In conclusion, both, phantom and clinical studies indicate that GCB radionuclide method is accurate, noninvasive for left ventricular volumes' measurement and should be widely used in everyday clinical practice.

[Scintigraphic diagnosis of inflammation and infection].

Nuclear medicine, diagnostic and therapeutic application of open sources of ionizing radiation in medicine, has wide range of possibilities for non-invasive infection and inflammation detection. The broad spectrum of methods, some of which are already in routine use while the others are still in the phase of investigation, improvement, or clinical trials, is presented. Most of the methods in routine use are capable of detection and localisation of both inflammation and infection. Antibiotic and antimicrobe peptides labelings have the possibility to diagnose infection and to differentiate it from inflammation, which is not the case with other scintigraphic methods. Availability of the radiopharmaceuticals and nuclear-medicine equipment, radiation exposure of the patient, clinical situation, the baseline pathophysiology of a process, and costs are the factors which contribute to the choice of the diagnostic approach. In order to ease the choice of the appropriate diagnostic method for inflammation/infection detection in different clinical situations, the recommendations from the ISORBE (International Society of Radiolabelled Blood Elements) are quoted.

[Initial 111In-platelet kinetics: indicator of platelet sequestration/destruction site or quality control of platelet labelling?].

Taking into consideration the existing disagreement in the literature, the aim of this paper was to estimate the value of the initial kinetics of autologous platelets labelled with 111In-oxinate, performed during the first 20 minutes after their intravenous injection. Two hypothesis were tested: 1. Initial 111In-platelet kinetics indicates the platelet sequestration site (in patients with normal mean platelet life span)/destruction site (in patients with shortened mean platelet life span), 2. Initial 111In-platelet kinetics indicates the quality of platelet separation and labelling procedure. We performed initial labelled platelet kinetics in thrombocytopenic patients (in order to test the first hypothesis) as well as in control (healthy) subjects (in order to test the second hypothesis). Thirty-nine persons were investigated: 33 with thrombocytopenia: 25 with shortened mean platelet life span, caused by chronic im mune thrombocytopenic purpura (ITP), eight with normal platelet life span and thrombocytopenia caused by myelodysplastic syndrome (MDS), six healthy, control subjects (C). In all 39 persons platelet blood count on the day of platelet labelling was determined, autologous platelet labelling with 111In-oxinate was performed, general and differential yields of platelet labelling (GYL and DYL), as well as mean labelled platelets life span were determined. Besides that, initial labelled platelets kinetics was performed with initial 111In-platelets accumulation in the liver (IPAL) calculation, as well as the late platelet kinetics for platelet sequestration index and platelet sequestration/destruction site determination. We obtained two types of initial labelled platelets kinetics (not only in the patients with shortened platelet life span, but also in the subjects with normal labelled platelets life span), which differed in the IPAL value and in the ratio of the liver and the heart radioactivity: IPAL < 20% and IPAL>20%. We found statistically significant difference in GYL and DYL between the two groups: IPAL<20% and IPAL > 20%. Both yields were higher in IPAL<20% group. There was no significant difference between the two IPAL groups in the platelet blood count, labelled platelet life span, sequestration index and sequestration site. No correlation could be found between IPAL on one side and platelet blood count, sequestration index, and sequestration site on another. We concluded that initial labelled platelet kinetics could not indicate the platelet sequestration/destructon site (which is accomplished by the late labelled platelets kinetics), but nevertheless, it is very sensitive and useful method of platelet separation and labelling quality control. While in vitro quality control parameters (GYL and DYL) indicate the quality of only one part of this procedure, initial labelled platelet kinetics reflects discrete platelet function disturbance that might happen from the moment of blood sample collection till the labelled platelets intravenous injection.

[Prediction of the splenectomy efficacy in chronic immune thrombocytopenic purpura].

The aim of this investigation was to estimate the possibility of predicting the splenectomy response in patients with chronic immune thrombocytopenic purpura (ITP). The patients' age, sex, megakaryocytes abundance, platelet blood count, production, life span, sequestration/destruction site were considered as possible predictive factors. Thirty-four ITP patients (23 female and 11 male) aged from five to 83 years were investigated. Platelet blood count ranged from 4 to 106 x 10(9)l (mean value was 43 x 10(9)/l). Megakaryocyte abundance was determined in 19/34 ITP patients. Megakaryocytes were numerous in 11/19, present in 7/19 ITP patients and in one patient low megakaryocyte number was registered. In all 34 ITP patients autologous platelet labelling with 111In-oxinate was performed and labelled platelets were reinjected to the ITP patients. This enabled platelet life span, production, sequestration index and sequestration/destruction site determination. Platelet life span ranged from 0,4-5 days (mean value was 1 day). Mean value for platelet production index was 1,1. Platelet sequestration/destruction site in 16 ITP patients was the spleen, and in two it was the liver. Mixed platelet sequestration/destruction site (the liver and the spleen) was registered in 7 ITP patients, while predominantly splenic sequestration/destruction was present in 9 ITP patients. All 34 ITP patients were later submitted to splenectomy, which is a therapeutic option in ITP. Splenectomy result was favorable in 28/34 ITP patients while it was unfavorable in 6/34 (17,6%). Highly significant correlation was noticed between the splenectomy result and platelet sequestration site (p < 0.01). On the other hand, there was no correlation between the splenectomy result on one side, and patient's age, sex, megakaryocyte abundance, platelet production, life span and blood count on the other. Splenectomy result was favorable in all ITP patients with splenic sequestration/detruction of labelled platelets. It was unfavorable in ITP patients with hepatic sequestration of labelled platelets. In ITP patients with mixed platelet sequestration (hepatic and splenic) there were more unfavorable than favorable splenectomy results. Non-invasive method of platelet labelling and platelet sequestration/ /destruction site determination makes easier the clinicians' and ITP patients' decision for the splenectomy in the case when the spleen is the only sequestration site of the labelled platelets, and against the splenectomy, when exclusively hepatic platelet sequestration/destruction is registered.

[Liver hemangioma blood pool as a function of time].

UNLABELLED: Aim of the study was to determine the time needed for establishing maximal labelled red blood cell concentration in hemangioma by scintigraphic semiquantitative blood pool estimation as a function of time. PATIENTS AND METHODS: Eleven patients (eight females and three males) with total number of fourteen liver hemangiomas have been examined. Nine of them had solitary lesions and remaininig two patients had two and three liver hemangiomas, respectively. All patients underwent blood pool scintigraphy 40, 60, 120 and 180 minutes after in vivo labelling of autologous red blood cells using 740 MBq of 99mTc. After correction for radioactive decay of 99mTc and back-ground correction blood pool indexes, as hemangioma/heart and liver/heart counting rate ratios, have been calculated. RESULTS: Mean blood pool indexes obtained 40-180 minutes after in vivo red blood cell labelling did not differ significantly (p > 0.05) neither in hemangioma (0.84-0.86) nor in liver tissue (0.55-0.58). In every acquisition time hemangioma blood pool index was substantialy higher than that of liver tissue (p < 0.01). CONCLUSION: The results of the study indicates that labelled red blood cells concentration reaches its plateau before 40th minute following in vivo labelling. The concentration difference between hemangioma and liver tissue also does not differ significantly after 40th minute of blood pool examination. In most patients blood pool scintigrams taken 60, 120 and 180 minutes following in vivo RBC labelling do not contribute to diagnostic value of the method.

Clinical significance of optimal red cell mass and plasma volume estimation methods.

BACKGROUND: The aim of this study was to present and compare the results of proposed methods for optimal red cell mass and plasma volume (RCM&PV) estimation, and their influence on the interpretation of obtained results. MATERIAL AND METHODS: In 120/280 patients with polycythaemia rubra vera, subjected to RCM&PV determination with autologous erythrocytes in vitro labelled with 51Cr-sodium chromate, optimal volumes were determined using: 1. traditional ml/kg of: --the real body weight method (ml/kg RBW); --the optimal body weight method (ml/kg OBW). 2. the body weight, height, and sex based method (Retzlaff's tables), 3. the method recommended by the International Council for Standardization in Haematology (ICSH), based on body surface area. RESULTS: Different interpretation of the same results of 120 RCM&PV measurements was registered in 48/120 patients (40%). The greatest disagreement existed between ml/kg RBW and ml/kg OBW methods (in 39/120 subjects, 32.5%). In underweight patients the ml/kg RBW method, and in overweight patients the ml/kg OBW method, offered better agreement with ICSH&Retzlaff's methods. The ml/kg RBW method disagreed with ICSH&Retzlaff's methods and ml/kg OBW in 25% and 19.2% of patients respectively. ICSH and Retzlaff's methods disagreed in 10/120 patients (8.3%). The ICSH method yielded significantly lower optimal volumes than Retzlaff's. CONCLUSION: Three methods for optimal RCM&PV estimation lead to different interpretations of the same results of RCM&PV measurements with 51Cr-erythrocytes in 40% of patients. Two ml/kg body weight methods show greater disagreement in comparison with ICSH and Retzlaff's methods, which differ significantly. The ICSH method yields lower optimal values compared to Retzlaff's.

111In-platelets dynamic study in chronic immune thrombocytopenic purpura.

BACKGROUND: The aim of this work was to estimate the significance of a dynamic study performed during the first 20 minutes after autologous (111)In-oxinate-platelets injection in patients with chronic immune thrombocytopenic purpura (ITP). Two hypotheses were tested: a) dynamic study indicates the place of platelet sequestration; b) dynamic study reflects the quality of platelet separation and labelling procedure. MATERIAL AND METHODS: Thirty-nine persons were investigated: 25 with shortened platelet life span (ITP), and 14 with normal platelet life span (6 healthy subjects and eight patients with myelodysplastic syndrome--MDS). Platelet blood count on the day of platelet labelling, general yield of platelet labelling (GYL), differential yield of platelet labelling (DYL), platelet life span, dynamic study with initial platelet accumulation in the liver (IPAL), sequential static study for determining the platelet sequestration index (SI) and platelet sequestration site (SS) were investigated. RESULTS: Two types of labelled platelet kinetics were determined in both groups of patients: IPAL < 20% and IPAL > 20%. A statistically significant difference in GYL and DYL was noted between the patients with IPAL < 20% and IPAL > 20%. No significant difference was registered in platelet blood count, life span, SS and SI between the two groups of patients. Both yields of platelet labelling were higher in the group with IPAL < 20%. There was no correlation between IPAL and platelet SI, or between IPAL and platelet SS. CONCLUSIONS: Dynamic study with (111)In-platelets cannot predict platelet sequestration site in ITP patients, but it is a useful and sensitive method of platelet labelling procedure quality control.