ABSTRACT
Resumen Introducción: Los estudios de imagen, como la tomografía simple y contrastada, son la primera aproximación diagnóstica para detectar la recurrencia de tumores musculoesqueléticos. El objetivo de este estudio retrospectivo fue demostrar la utilidad de la gammagrafía acoplada a tomografía computarizada por emisión de fotón único (SPECT/CT) con talio-201(201Tl) en la valoración de tumores musculoesqueléticos malignos con sospecha de recurrencia o enfermedad metastásica. Métodos: Se realizaron 72 estudios gammagráficos y de SPECT/CT para la valoración de la recurrencia locorregional y a distancia, al menos 8 semanas tras la última terapia, en 42 pacientes con diferentes tipos de tumores musculoesqueléticos malignos, como osteosarcoma, sarcoma de Ewing, rabdomiosarcoma, retinoblastoma, sarcoma sinovial y tumor de Wilms en el Hospital Infantil de México. Se calcularon el valor predictivo positivo (VPP) y el intervalo de confianza del gammagrama y de la SPECT/CT en comparación con el resultado del análisis histopatológico y el seguimiento clínico y radiológico para identificar la recurrencia. Resultados: La gammagrafía fue anormal en 30 (71.4%) de los 42 pacientes. Se detectaron 33 lesiones (30 pacientes) por gammagrafía y 25 (21 pacientes) por telerradiografía de tórax y tomografía de dos regiones. La SPECT/CT se realizó en 30 pacientes y se detectaron 12 lesiones adicionales al rastreo planar. El VPP con la gammagrafía fue del 82%, y con la SPECT/CT, del 100%. Conclusión: La gammagrafía con 201Tl puede considerarse un estudio adecuado para identificar los sitios de viabilidad tumoral, con alto grado de certeza diagnóstica al complementar con SPECT/CT.
Abstract Background: Imaging studies, particularly simple and contrast-enhanced tomography, constitute the first diagnostic approach to detect recurrence of musculoskeletal tumors. The aim of the present retrospective study was to demonstrate the usefulness of scintigraphy plus SPECT/CT (single photon emission computed tomography) with thallium-201 (201Tl) in the evaluation of malignant musculoskeletal tumors with suspicion of recurrence or metastatic disease. Methods: Eight weeks after the last therapy, 72 scintigraphy and SPECT/CT studies were performed to assess regional recurrence and metastatic disease in 42 patients with different types of malignant musculoskeletal tumors, such as osteosarcoma, Ewing's sarcoma, rhabdomyosarcoma, retinoblastoma, synovial sarcoma, and Wilms tumor at the Hospital Infantil de México Federico Gómez. The positive predictive value (PPV) and the confidence interval of the scintigraphy and SPECT/CT were calculated when compared with the results of the histopathological analysis and the clinical and radiological follow-up for the identification of recurrence. Results: Scintigraphy was abnormal in 30 (71.4%) of the 42 patients; 33 lesions (30 patients) were detected by scintigraphy and 25 lesions (21 patients) by chest X-ray and tomography of two regions. The SPECT/CT was performed on 30 patients, where 12 lesions were detected in addition to the planar scintigraphy. Scintigraphy showed a PPV of 82%; SPECT/CT, 100%. Conclusion: 201Tl-scintigraphy can be considered as an adequate study to identify the sites of tumor viability with a high degree of diagnostic certainty combined with the SPECT/CT technique.
Subject(s)
Adolescent , Child , Child, Preschool , Female , Humans , Male , Bone Neoplasms/diagnostic imaging , Muscle Neoplasms/diagnostic imaging , Single Photon Emission Computed Tomography Computed Tomography/methods , Bone Neoplasms/pathology , Thallium Radioisotopes/administration & dosage , Radionuclide Imaging/methods , Predictive Value of Tests , Retrospective Studies , Follow-Up Studies , Muscle Neoplasms/pathology , Mexico , Neoplasm Recurrence, LocalABSTRACT
Objective - To compare single-photon-emission computed tomography (SPECT) imaging scans using (201)Tl and (99m)Tc-MIBI in detection of viable myocardium, in regions compromised by infraction. Methods - Thirty-two (59.3+9.8 years old and 87 per cent male) myocardial infarction patients were studied. All had Q waves on the ECG and left ventricle ejection fraction of <50 per cent. They underwent coronary and left ventricle angiographies and SPECT before (including (201)Tl reinjection) and after coronary artery bypass surgery (CABG). Improvement in perfusion observed after surgery was considered the gold standard for myocardial viability. Results - Among 102 studied regions of the heart, there were 40 (39.2 per cent) areas of transient perfusion defects in the conventional protocol with (201)Tl and 52 (51.0 per cent) after reinjection. Therefore, 12/62 (19.4 per cent) more viable regions were identified by reinjection. Using (99m)Tc-MIBI, only 14 (13.7 per cent) regions with transient defects were identified, all of which were seen also in (201)Tl protocols. After surgery, 49 of total of 93 regions analyzed (52.7 per cent) were viable. Sensitivity, specificity, accuracy, positive and negative prediction values were, respectively, (201)Tl SPECT scans-65.3 per cent, 90.9 per cent, 77.4 per cent, 88.9 per cent and 70.2 per cent, reinjection protocol with (201)Tl scans - 81.6 per cent, 81.8 per cent, 81.7 per cent, 83.3 per cent and 80.0 per cent; (99m)Tc-MIBI SPECT scans - 20.4 per cent, 90.9 per cent, 53.8 per cent, 71.4 per cent and 50.6 per cent. Logistic regression demonstrated that the reinjection protocol with (201)Tl was the best predictor of viability (P<0.001). Conclusion - Our data suggest the election of (201)Tl for viability studies, especially when using the reinjection protocol.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Myocardial Infarction/surgery , Myocardial Revascularization , Myocardium , Tissue Survival , Exercise , Heart , Postoperative Period , Predictive Value of Tests , Sensitivity and Specificity , Thallium Radioisotopes , Thallium Radioisotopes/administration & dosage , Tomography, Emission-Computed, Single-PhotonABSTRACT
Assessment of myocardial blood flow has been the subject of extensive research and study, ever since coronary artery disease has been recognised as a first rate killer of mankind. Non-invasive methods like routine ECG, exercise ECG, 2-D echocardiography lack sensitivity and specificity. The specificity of exercise ECG becomes less in patients with ventricular hypertrophy, intraventricular conduction delay, left bundle branch block (LBBB), previous myocardial infarction, subendocardial infarction, non specific ST-T changes at rest and exercise, and electrolyte imbalance; those taking various drugs such as digitalis and quinidine; and in evaluation of post bypass graft or post PTCA (percutaneous transluminal coronary angioplasty) status. Coronary angiography, which is an invasive procedure, provides direct proof of the presence and extent of coronary artery disease in the form of anatomical changes like luminal narrowing. It fails to give any information regarding small vessel disease or bridging of vessels in the cardiac musculature and in those with normal coronaries with anginal pain at stress. It also fails to provide direct information regarding myocardial tissue perfusion, which ultimately decides the outcome of the disease. In addition, coronary angiography involves some percentage of risk to the patient. It is in this context that thallium 201 myocardial scintigraphy occupies a unique position. It has none of the disadvantages of exercise ECG and it directly reflects myocardial perfusion at the tissue level. Stress thallium 201 scintigraphy directly quantitates the amount of myocardium involved as a result of previous myocardial infarction or ischaemia, unlike stress ECG and other non-invasive modalities.(ABSTRACT TRUNCATED AT 250 WORDS)