Leukocyte-technetium-99m uptake in Crohn's disease: does it show subclinical disease?

AIM: To evaluate inflammatory activity in patients with Crohn's disease (CD) using technetium-99m-hexamethylpropyleneamine oxime (99mTc-HMPAO) granulocyte scintigraphy. METHODS: Twenty patients (7 male and 13 female) with CD and five healthy volunteers were selected for 99mTc-HMPAO granulocyte scintigraphy. The Crohn's Disease Activity Index (CDAI), blood tests and C-reactive protein (CRP) of each patient were performed 7 d before the scintigraphic images. The leukocytes were labeled according to the International Society of Radiolabeled Blood Elements (ISORBE) consensus protocol and the scintigraphic images, including single photon emission computed tomography, were obtained 30 min and 2 h after injection of the radiolabeled leukocytes. RESULTS: The labeling yield of the leukocytes with the lipophilic complex 99mTc-HMPAO was 55.0% +/- 10%. Six of the 20 patients (30%) presented congruent results for the three parameters investigated (CDAI, Scintigraphic Index and CRP). On the other hand, 14 patients (70%) did not show congruent results. There was no significant correlation between the indices analyzed according to the Spearman test (P > 0.05, n = 20). CONCLUSION: The results suggest that 99mTc-HMPAO-labeled leukocyte scintigraphy could be important for determining inflammatory activity in CD even in the absence of clinical symptoms.

Removal of the internal mammary sentinel node in breast cancer.

OBJECTIVE: The aim of the study was to determine the evolution of patients with internal mammary chain (IMC) drainage whether the IMC-sentinel lymph node (IMC-SLN) was biopsied or not, as well as to determine the clinical implications of the biopsy of the IMC-SLN (IMC-SLNB) in patients with breast cancer and IMC drainage in the lymphoscintigraphy. METHODS: Eighty-two out of 914 patients included in a prospective database of sentinel node (9%) showed IMC drainage and were included in the study. Two groups were established depending on the IMC-SLN removal: group A (IMC-SLN were removed): 44 patients, mean age 48.8 years, mean follow-up, 35.8 months. Group B (IMC-SLN were not removed): 38 patients, mean age 54.5 years, mean follow-up, 33.5 months. Kaplan-Meier plots were used to determine the overall survival rates. RESULTS: Group A: four patients showed only IMC drainage, six patients presented positive IMC-SLN, nodal staging changed in five patients, treatment changed in two patients and tumour node metastasis stage grouping changed in three patients. All patients are currently disease-free. Group B: two patients showed only IMC drainage, axillary-SLN were positive in 12 patients, one patient presented nodal axillary and breast recurrence as well as distant disease and one patient presented multiorganic disease. This last patient died. The overall survival rates were very similar in both the groups. CONCLUSION: IMC-SLNB improves nodal staging in breast cancer but has little impact on adjuvant treatment. However, it should be performed to obtain results, which will determine in the future whether it improves survival rates or not.

Scintigraphic imaging using technetium-99m-labeled ceftizoxime in an experimental model of acute osteomyelitis in rats.

PURPOSE: To investigate inflammatory (zymosan) and infectious (Staphylococcus aureus) processes in experimental models in rats using technetium-99m-labeled ceftizoxime (CFT). METHODS: Male Wistar rats were used for the development of the inflammatory (zymosan) and infectious (S. aureus) processes in the medullary cavity of the left tibia. Sterile saline was used for the control group. At 48 h after induction of the processes, the animals were anesthetized and scintigraphic images were acquired at 1, 2, 4, and 6 h after intravenous injection of 0.1 ml of 99mTc-CFT (55 MBq). Quantitative analysis of the scintigraphic images was performed by counting the radioactivity in the regions of interest. Samples of tibia were taken for histopathological examination. RESULTS: The images showed that 99mTc-CFT presented higher tropism to infectious foci than with the inflammatory site. The average value of the target/nontarget ratio of the 99mTc-CFT was significantly higher in the infected (2.40+/-0.22) than in the inflamed tibia (1.50+/-0.05) and the control group (1.05+/-0.04) for all of the investigated times. The histological data showed a similar inflammatory response for both the S. aureus and zymosan groups. CONCLUSION: The 99mTc-CFT presented a high tropism and retention for an infected region in this model of osteomyelitis, thereby constituting an interesting strategy to distinguish aseptic from septic sites.

Particle sizes of colloids to be used in sentinel lymph node radiolocalization.

OBJECTIVES: To investigate particle size distribution and possible effects of colloid concentration and time after its preparation on the particle sizes of albumin nanocolloid (Nanocoll), rhenium sulfide nanocolloid (Nanocis) and tin colloid (Hepatate). METHODS: All three kits were prepared according to the manufacturers' instructions using the following volumes of decayed Tc generator eluate: 1.5 ml, 3.5 ml and 5.0 ml (albumin nanocolloid); 1.0 ml, 2.0 ml and 3.0 ml (rhenium sulfide nanocolloid); 3.0 ml, 5.0 ml and 9.0 ml (tin colloid). The particle sizes were determined by photon correlation spectroscopy inmediately after preparation, then at 30 min, 1 h, 2 h, 3 h and 4 h (all three kits) and at 6 h (Nanocoll and Hepatate). Each measurement was performed in three different preparations. RESULTS: The particle sizes of the three colloids did not change significantly after preparation throughout their period of validity. For Nanocoll, 95% of the particles were between 3 and 16 nm, approximately (mean around 8 nm). Small (< or =1 nm) but significant variations on the mean diameter were found depending on the volume of pertechnetate used in the preparation. For Nanocis, 95% of the particles were between 8 and 68 nm, approximately (mean around 23-25 nm). In this kit, there were no significant differences among colloidal suspensions prepared with different volumes of pertechnetate. For Hepatate, 95% of the particles were between 33 and 255 nm, approximately (mean, around 72-90 nm). The upper limit and the mean size increase with the volume of eluate used were from 190 nm and 73 nm (3 ml) to 255 nm and 85 nm (9 ml). CONCLUSIONS: The particle sizes of Nanocoll, Nanocis and Hepatate are very stable throughout their period of validity. For Nanocoll, 95% of particles have a diameter <16 nm, with a mean diameter around 8 nm. There are small (< or =1 nm) but significant variations on the mean diameter depending on the volume of pertechnetate used in its preparation. For Nanocis, 95% of particles have a diameter <70 nm, with a mean around 24 nm, and are independent of the volume of pertechnetate used in their preparation. For Hepatate, the upper size limit for 95% of particles is between 190 and 255 nm, with a mean between 72 and 88 nm, depending on the volume of pertechnetate used in its preparation. This tin colloid could be a good candidate for evaluating clinical suitability in sentinel node localization.

Patients with breast cancer and negative sentinel lymph node biopsy without additional axillary lymph node dissection: a follow-up study of up to 5 years.

OBJECTIVE: To analyze the rate of axillary recurrences and survival in patients operated on for breast cancer who had not undergone an axillary lymph node dissection (ALND) because of a negative sentinel node biopsy. METHODS: The study includes 97 patients operated on for breast cancer and selective node biopsy from June 2000 to December 2001 who had a negative sentinel node biopsy and did not undergo ALND. Mean age was 58.2 years (55.9-60.5). Follow-up was done up to 5 years. After surgery all patients underwent clinical examination. Complementary treatment depended on the hospital protocol. Rate of axillary recurrences, presence of distant metastases and survival (Kaplan-Meier method) were studied. RESULTS: After a median follow-up of 4.1 years (2.18-5.25), only 2/95 patients (2.1%) developed distant metastases. Four patients died but only the death of the patient who presented multiple metastases was related to the primary breast cancer (1%). The 5-year overall survival rate was 96%. CONCLUSIONS: (1) Only 1/95 patients studied developed nodal extra-axillary recurrence together with distant metastases. (2) The results obtained support the selective sentinel node biopsy as an accurate technique in the axillary stratification of patients with breast cancer, offering in the cases of negative sentinel node biopsy a safe axillary control after a 5-year follow-up.

Technetium-99m ceftizoxime kit preparation

The aim of this work was to prepare a kit of 99mTc-ceftizoxime (99mTc-CFT), with stability and biological activity preserved, able to identify a septic focus (E. coli) in the experimental infection model in rats. The preparation of the CFT kit involved the use of lyophilized solutions containing the antibiotic ceftizoxime and the sodium dithionite reducing agent (6.0 mg/mL). After lyophilization, the kit was reconstituted with 1.0 mL of sodium 99mTc-pertechnetate solution (Na99mTcO4-) with an activity of 370 MBq. The solution was boiled for 10 min and filtered through a cellulose ester filter. The labeling efficiency was on the order of 92 percent, remaining stable for six hours and the kit remained stable for two months. The biological activity of the 99mTc-CFT was evaluated by diffusion in agar impregnated with E.coli and S. aureus. Seven Wistar rats, weighing from 200 to 250 g, were used for the development of the septic focus. After 24 hours from the induction of the infectious site (E.coli), the animals were anesthetized and 0.1 mL of 99mTc-CFT (37 MBq) was injected into the tail veins of the animals. The images were obtained with a gamma camera one, two and six hours after injection and the regions of interest (ROIs) were calculated. The diameters of the inhibition halos for 99mTc-CFT were 27.16 ± 0.23 and 27.17 ± 0.20 for S.aureus and E.coli, respectively, while those for the unlabeled CFT were 30.4 ± 0.33 and 29.43 ± 0.26, respectively. The results for the biodistribution of 99mTc-CFT in infected animals furnished a ratio of 1.97 ± 0.31, 2.10 ± 0.42 and 2.01 ± 0.42 for cpm-target/cpm-no target for the one, two and six-hour periods, respectively. The images showed a clear uptake of labeled antibiotic (99mTc-CFT) by the infectious site during the experiment. The results attest to the viability of producing a kit with 99m technetium-labeled ceftizoxime for the investigation of infectious processes.

O objetivo deste trabalho foi preparar um kit de Tc-99m Ceftizoxima (99mTc-CFT), com estabilidade e atividade biológica preservadas, capaz de identificar um foco séptico (E.coli) em um modelo experimental de infecção em ratos. A preparação do kit de CFT baseou-se em uma mistura de soluções contendo o antibiótico ceftizoxima (2,5mg/mL) e o agente redutor ditionito de sódio (6,0mg/mL) que foram submetidos a um processo de liofilização. Após a liofilização, o kit foi reconstituído with 1,0 mL de solução de pertecnetato de sódio (Na99mTcO4 -), contendo uma atividade de 370 MBq. Em seguida, a solução foi incubada, por 10 min, em banho fervente (1000C) e, posteriormente, foi resfriada em água corrente por 5 min. A eficiência de marcação foi da ordem de 92 por cento permanecendo estável por 6 horas e o kit permaneceu estável por 2 meses. A atividade biológica do 99mTc-CFT foi avaliada por difusão em ágar impregnado com E.coli e S. aureus. Foram utilizados 07 ratos Wistar, pesando entre 200 a 250 g, para o desenvolvimento do foco séptico. Após 24 horas da indução do foco infeccioso (E.coli), os animais foram anestesiados e 0,1 mL da 99mTc-CFT (37 MBq) foi injetado na veia da cauda dos animais. As imagens de 1, 2 e 6 horas após a injeção foram adquiridas em uma gama câmara e as regiões de interesse (ROIS) foram calculadas. Os valores obtidos dos diâmetros dos halos de inibição para 99mTc-CFT foram 27,16±0,23 e 27,17±0,20 para S. aureus e E.coli, respectivamente, sendo que para CFT não marcada foram 30,4±0,33 e 29,43±0,26, respectivamente. Os resultados obtidos da biodistribuição da 99mTc-CFT nos animais com focos infecciosos mostraram uma relação alvo/não alvo de 1,97±0,31, 2,10±0,42 e 2,01±0,42 para os tempos de 1, 2 e 6 horas, respectivamente. As imagens obtidas mostraram nítida captação do antibiótico marcado (99mTc-CFT) pelo foco infeccioso ao longo do experimento. Os resultados obtidos neste...

Factors associated with the non detection of the sentinel node in breast cancer

The aim of the work was to analyse the potential influence of different factors on the surgical detection of sentinel lymph node in breast cancer. The procedure has been performed in 704 patients. In 43 out of the 704 cases, the SN was not detected, 24 were palpable and 19 had no palpable tumors. Lymphoscitigraphy was done in 2 h p.i. of 37-55 MBq of 99mTc-nanocolloid. The day before surgery in palpable tumours and 4 h previous to surgery in non-palpable tumours, surgical detection was performed using a gammaprobe. The following factors were analysed: patient age, tumour size, breast quadrant tumour localization, scintigraphic visualizatio,n and the palpation of the tumour. Results: Patient age was significantly (p<0.001) higher in the patients in whom SN was not detected. Scintigraphic visualization was significantly (p<0.05) lower in the patients in whom SN was not detected. There were no significant differences concerning the other parameters analysed. Conclusion: patient age and scintigraphic visualization are parameters that directly influence the detection of sentinel node in breast cancer.

O objetivo deste trabalho foi analisar a possível influencia de diferentes fatores na detecção cirúrgica de linfonodos sentinela no câncer de mama. O procedimento foi realizado em 704 pacientes. Em 43 dos 704, o linfonodo sentinela não foi detectado, 24 eram palpáveis e 19 eram tumores não palpáveis. Foi realizada a linfocintilografia 2 horas após a injeção de 37-55MBq de 99mTc-nanocolóide. No dia anterior à cirurgia nos tumores palpáveis e nas 4 horas prévias à cirurgia de tumores não palpáveis foi realizada detecção cirúrgica com a gammaprobe. Foram analisados os seguintes fatores: idade do paciente, tamanho do tumor, quadrante de localização do tumor de seio, visualização cintilográfica e palpação do tumor. Resultados: a idade do paciente foi significativamente maior (p<0,001) nos pacientes nos quais o nódulo sentinela não foi detectado. Não foram observadas diferenças estatisticamente significativas com relação ao outros parâmetros estudados. A idade do paciente e a visualização cintilográfica são parâmetros que influenciam diretamente na detecção de nódulo sentinela em câncer de mama.

Succinylated gelatine: an alternative to hydroxyethyl starch for labelling leukocytes with 99mTc-HMPAO.

BACKGROUND: Hydroxyethyl starch (HES) is the most used plasma expander in the sedimentation of the erythrocytes during the radiolabelling procedure for leukocytes in vitro. AIM: To evaluate the usefulness of succinylated gelatine (GEL), another colloidal plasma expander, as an alternative to HES in this process. METHODS: Two identical blood samples were obtained from 30 patients referred to white blood cell scintigraphy. The first sample was used to label leukocytes with Tc-HMPAO using the routine procedure, with HES. The other sample was used to label leukocytes with Tc-HMPAO using the same procedure, with GEL. The cell concentration of the leukocyte-platelet-rich plasma (LPRP) achieved after blood sedimentation was analysed. Labelling efficiency was calculated and the eosin Y viability and red cell/leukocyte ratio were evaluated from the final labelled cell suspension. RESULTS: Leukocytes and platelets recovered in LPRP were not statistically different between both HES and GEL samples (leukocytes: 8.10x10/microl+/-3.82 and 7.80x10/microl+/-3.47; platelets: 411x10/microl+/-182 and 406x10/microl+/-172, respectively). There were no significant differences between both agents on the labelling efficiency (HES: 80.3%+/-6.6%; GEL: 80.1%+/-6.3%), the eosin Y viability (HES: 99.2%+/-1.3%; GEL: 99.3%+/-1.1%) and the red cell/leukocyte ratio (HES: 1.21+/-0.7; GEL: 0.9+/-0.5). CONCLUSION: These results show that succinylated gelatine can be used instead of hydroxyethyl starch in the labelling of leukocytes with Tc-HMPAO.

What is the role of bone scintigraphy in the diagnosis of infected joint prostheses?

AIM: To analyse the role played by bone scintigraphy in the diagnosis of infected joint prostheses. METHODS: The study included 77 patients, aged 32-77 years, in whom infection of a joint prosthesis (48 hip, 29 knee) was suspected. In all patients the following examinations were performed consecutively: a two-phase Tc methylene diphosphonate (Tc-MDP) bone scan, a Tc hexamethylproplyene amine oxime (Tc-HMPAO) labelled white blood cell (WBC) scan, and a Tc microcolloid bone marrow (BM) scan. The minimum interval between examinations was 48 h. The diagnoses were based on data obtained from bacteriological cultures. RESULTS: The bone scan was positive in all patients and 28 of them had an infection (sensitivity 100%, specificity 0%). The WBC scan was positive in 61 patients but only 27 had an infection. The WBC scan was negative in 16 patients, and the possibility of infection was discarded in 15 of these cases (sensitivity 96%, specificity 30%). The results of the bone marrow scan were not compatible with those of the WBC scan (suggestive of infection) in 27 patients: 26 of them had prosthesis infection. The results of both examinations were compatible in the other 34 patients and the possibility of infection was discarded in 33 of these patients (sensitivity 92.8%, specificity 98%). The addition of a BM scan to a WBC scan decreased the sensitivity from 96% to 92.8% but increased specificity from 30% to 98%. The addition of a bone scan to this dual combination did not alter the results. CONCLUSIONS: When infection of a prosthesis is suspected the diagnostic procedure should start with a WBC scan followed, if positive, by a BM scan. This procedure reduces the cost, the time required for a diagnosis, and the dose of radiation received by the patient.

[Physiologic evaluation of coronary circulation. Role of invasive and non invasive techniques]. / Valoración fisiológica de la circulación coronaria. Papel de las técnicas invasivas y no invasivas.

For many years, the evaluation of the extent and severity of coronary artery disease has been mainly anatomical, carried out by coronary angiography. However, this technique has methodological limitations and interobserver variability is considerable. Quantification of coronary reserve with pressure guidewires and intracoronary Doppler now provides more precise physiologic evaluation of coronary circulation. Myocardial perfusion single proton emission computed tomography and echocardiography, combined with stress and/or pharmacological challenge testing, though they are only semiquantitative techniques, also offer appropriate complements to coronary angiography in the functional evaluation of coronary patients. The aim of this paper is to discuss the clinical value of these techniques.

Comparación del citrato de galio-67 de los leucocitos marcados con exametazina-tecnecio-99m y de la inmunoglobulina G marcada con DTPA-indio-111 en el diagnóstico de infecciones óseas y articulares / Comparison between 67-gallium citrate of exametazine-T-99m labelled leucocites and the DTPA-indio-111 labelled G immunoglobuline in the diagnosis of bone and articular infections

El objetivo de este estudio ha sido comparar la capacidad de la gammagrafia con citrato de Gálio-67 (67Ga), de los leucocitos marcados con Tc-99m (99mTc-leucocitos) y de la inmunoglobulina G marcada con In-111 (111In-IgG) en el diagnóstico de infecciones óseas y articulares. Han sido estudiados 56 pacientes. En todos ellos se indicó una gammagrafia ósea (99mTc-MDP). Los pacientes han sido aleatoriamente asignados para estudios con 67Ga (Grupo 1 - 22 pacientes) o con la administración simultánea de 99mTc-leucocitos y con 111In-IgG.(Grupo 2 - 34 pacientes). Para los grupos 1 y 2 han sido confirmadas 12/26 y 11/34 lesiones sépticas respectivamente. La gammagrafia con 67Ga mostró 6 verdadero-positivos, 9 verdadero-negativos, 5 falso-positivos y 6 falso-negativos. Con los 99mTc-leucocitos, los resultados han sido 8, 18, 5 y 3, respectivamente. Con la 111In-IgG, 7, 17, 6 y 4, respectivamente. La sensibilidad, especificidad y precisión han sido respectivamente del 50 por ciento, 64,3 por ciento y 57,7 por ciento para el 67Ga, 72,7 por ciento, 78,2 por ciento y 76,4 por ciento para los 99mTc-leucocitos y 63,6 por ciento, 73,9 por ciento y 70,6 por ciento para la 111In-IgG. En este estudio, la gammagrafia con los leucocitos marcados presentó mayor precisión que con 67Ga y con 111In-IgG en el diagnóstico de infecciones óseas y articulares. Sin embargo, en el diagnóstico de infecciones en prótesis articulares los resultados han sido menos fiables