RESUMEN
This study aimed to detect metastases in patients with stage III or IV cutaneous melanoma by (18)F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT). Thirty-nine patients with clinically evident stage III or IV melanoma underwent whole-body FDG-PET/CT scans for metastatic disease and these results were compared with those of biopsy. Scans for 38 of the patients were evaluated; one patient's scan could not be evaluated. There were 11 true-positive, two false-positive, 24 true-negative and one false-negative scans for the detection of melanoma metastases, with sensitivity 91%, specificity 92%, accuracy 92%, and positive and negative predictive values 84% and 96%, respectively. False-positive FDG-PET/CT scans were due to sarcoidosis in the lung and infected cyst in the liver. It is concluded that FDG-PET/CT scanning has high sensitivity and specificity for detecting stage III or IV metastatic melanoma.
Asunto(s)
Fluorodesoxiglucosa F18 , Melanoma/diagnóstico por imagen , Melanoma/secundario , Metástasis de la Neoplasia/diagnóstico por imagen , Radiofármacos , Neoplasias Cutáneas/diagnóstico por imagen , Neoplasias Cutáneas/patología , Tomografía Computarizada de Emisión , Adulto , Errores Diagnósticos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Standardized uptake values (SUVs) of normal organs were evaluated by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography and computed tomography (PET-CT) scanning. Seventy patients (38 men and 32 women) with no non-physiological 18F-FDG uptake participated in the study. All patients fasted for at least 4 h before PET-CT imaging and their fasting blood glucose levels were within the normal range. Image acquisition was performed after intravenous administration of 18F-FDG and images were obtained from the vertex to the upper thigh region. The SUVs of various organs were determined from the transverse views. The uptake of 18F-FDG was highest in the cerebrum, cerebellum, myocardium, tonsils, liver and spleen in both sexes. Having knowledge of the physiological uptake of 18F-FDG and normal organ SUVs is required for the correct interpretation of whole-body 18F-FDG-PET-CT studies.
Asunto(s)
Fluorodesoxiglucosa F18/farmacocinética , Tomografía de Emisión de Positrones , Tomografía Computarizada por Rayos X , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Distribución TisularRESUMEN
PURPOSE: Current dacryoscintigraphy methods have several potential pitfalls, the most important of which is the outflow of tears. Another is the difficulty in fixing the head with the patient seated. To overcome these difficulties, a new method was applied. MATERIALS AND METHODS: The study included 77 persons: 43 controls and 34 patients with epiphora. Two methods were applied to the two groups. In the first, protocol 1 (the current conventional protocol), the patient was seated in front of a gamma camera and one drop (50 microl) Tc-99m pertechnetate containing 50 to 100 microCi radioactivity was instilled in the inferior fornix or outer canthus of the eye and dynamic and static images were obtained for approximately 15 to 20 minutes. In the other, protocol 2 (our protocol), 100 microCi (10 microl) Tc-99m pertechnetate was instilled in the outer canthus of the eye using a micropipette with the patient in the supine position under the gamma camera. Dynamic images were taken for only 5 minutes. CONCLUSION: The pitfalls and difficulties seen with protocol 1 were lessened to a great degree in protocol 2.
Asunto(s)
Enfermedades del Aparato Lagrimal/diagnóstico por imagen , Aparato Lagrimal/diagnóstico por imagen , Radiofármacos , Pertecnetato de Sodio Tc 99m , Adulto , Femenino , Humanos , Masculino , Cintigrafía , Radiofármacos/administración & dosificación , Pertecnetato de Sodio Tc 99m/administración & dosificaciónRESUMEN
This study aimed to investigate the microvascular pathology in the lower limbs of diabetic patients without symptoms or findings of peripheral ischaemia by measuring perfusion reserve scintigraphically. It was carried out in 47 female subjects who had no evidence of peripheral arterial disease in their history, physical examination or Doppler ultrasonography. The diabetic group consisted of 25 women (mean age 54.2 +/- 3.54 years) with type II diabetes mellitus of more than 10 years' duration. A control group consisted of 22 healthy non-diabetic women (mean age 50.14 +/- 6.75 years). Each subject flexed their right foot maximally both dorsally and plantar 60 times. In the middle of this exercise, 370 MBq technetium-99m-methoxyisobutylisonitrile (99Tc(m)-MIBI) was injected intravenously. Ten minutes after the injection, a posterior image of both calves was obtained using a gamma camera. Rectangular regions of interest were symmetrically drawn over both calves. The total count in the resting calf was subtracted from the total count in the exercising calf, and the percentage increase, termed the perfusion reserve, was determined. A significant difference was found between the perfusion reserves of the diabetic and control groups (76.04 +/- 12.96% and 95.91 +/- 12.83%, respectively; P<0.001). In conclusion, microvascular pathology may be determined scintigraphically by measuring the perfusion reserve in the lower limb muscles in diabetic patients. This method may also be used to evaluate perfusion abnormalities in other circulatory disorders.
Asunto(s)
Diabetes Mellitus/fisiopatología , Isquemia/diagnóstico por imagen , Pierna/irrigación sanguínea , Enfermedades Vasculares Periféricas/diagnóstico por imagen , Tecnecio Tc 99m Sestamibi , Femenino , Humanos , Persona de Mediana Edad , Cintigrafía , Flujo Sanguíneo Regional , Reproducibilidad de los ResultadosRESUMEN
Eustachian tube (ET) dysfunction is one of the most important factors in the etiology of middle ear disease. There are several methods to assess the functions of ET which show the anatomic patency of the tube. However, functional patency of ET should be evaluated as well. For this reason, we used a scintigraphic method at 42 patients who had otitis media with effusion (study group) and traumatic perforation of the ear drum (control group) at 32 and 10 of them, respectively. After instillation of 100 microCi (100 microliters) Technetium 99m-macro-aggregated albumin (Tc99m-MAA) into the middle ear, 60 images were taken at 15 second intervals. Both groups were investigated as to whether there was radioactivity passage through ET and, the arrival time of the radioactivity to ET and to nasopharynx were calculated if the passage occurred. Radioactivity passage rates in the study and control groups were 5 (16%) and 10 (100%), respectively. The difference between both groups was statistically very significant (Chi-square, p < 0.001). Scintigraphy is a feasible tool for the assessment of ET functions. Scintigraphic methods should be improved and be used as a tubal function test in the future.
Asunto(s)
Trompa Auditiva/diagnóstico por imagen , Trompa Auditiva/fisiología , Otitis Media con Derrame/fisiopatología , Adolescente , Niño , Preescolar , Diagnóstico Diferencial , Trompa Auditiva/fisiopatología , Estudios de Evaluación como Asunto , Femenino , Humanos , Masculino , Otitis Media con Derrame/diagnóstico por imagen , Cintigrafía , Radiofármacos , Agregado de Albúmina Marcado con Tecnecio Tc 99m , Membrana Timpánica/lesionesRESUMEN
Our aim was to assess the value of quantitative bone scintigraphy for evaluating long-bone growth and to establish the normal uptake patterns of the growth plate in children. Subjects (180 girls, 154 boys) of normal weight and height, aged 2-20 years, were investigated using skeletal scintigraphy. Regions of interest were outlined over posterior images of the distal femoral growth plate and femoral diaphysis. The average number of counts per fixel in each region of interest was determined. The ratio of uptake in the distal femoral growth plate to that in the femoral diaphysis (GP:D ratio) was calculated for all subjects, and its relationship with age was determined. Peak GP:D ratios in girls and boys were reached at ages 11 and 13 years, respectively (8.26 in girls and 8.18 in boys), corresponding to the periods of most rapid growth. Our findings suggest that determining the scintigraphic GP:D ratio may be useful for evaluating growth and development in children if normal standard GP:D ratios are established.