Fausto Haruki Hironaka

Cardiac and skeletal muscle scintigraphy in dermato- and polymyositis: Clinical implications

To determine the role of scintigraphy in the detection of skeletal and cardiac involvement in dermato-and polymyositis (DM/PM), we studied 30 patients with a confirmed diagnosis of DM/PM (23 females, 7 males; mean age: 35 years). Technetium-99m pyrophosphate (99mTc-PYP) and gallium-67 scans showed similar sensitivity, specificity and accuracy in the detection of skeletal muscle involvement when compared with serum enzymes (70%, 100% and 80%, respectively). Compared with the clinical parameters,99mTc-PYP showed 70% and67Ga 65% accuracy. Abnormal PYP cardiac uptake was observed in 57% of patients, whereas abnormal67Ga cardiac uptake was seen in only 15%. Electrocardiography was abnormal in 40%, rest gated blood pool study in 23%, and chest X-ray in 13%. In conclusion, both99mTc-PYP and67Ga can be useful in the detection of the active phase of muscle disease. However,99mTc-PYP seems to be more effective than67Ga in the early diagnosis of cardiac involvement.

The role of gallium-67 scan in defining the extent of disease in an endemic deep mycosis, paracoccidioidomycosis: a predominantly multifocal disease

The tools currently used to evaluate the extent of paracoccidioidomycosis (PCM) may be of limited value in detecting subclinical lesions. The aim of this study was to verify the role of gallium-67 whole-body scan in evaluating the extent of disease of 65 patients with active PCM. The 67Ga scan findings were compared with the results of clinical evaluation, chest radiography and/or high-resolution computed tomography (CT), abdominal ultrasound (US) or CT, laryngoscopy, CT or magnetic resonance imaging (MRI) of the head, and technetium-99m methylene diphosphonate bone scan, obtained before treatment. Clinically unsuspected lesions were detected by imaging procedures in 21 patients (32%), mainly in the lungs (n=11), adrenals (n=6), and superficial (n=3) and deep lymph nodes (n=14). 67Ga scan detected 100% of the cases with subclinical involvement in the lungs. Scintigraphy was superior to chest radiography in demonstrating lung disease (94% vs 81%). The lymphatic lesions were demonstrated by 67Ga scan in all the clinically suspected cases and in nearly all unsuspected cases, and also revealed more extensive involvement than was clinically suspected in many of them. There was good agreement between 67Ga scan and the other imaging procedures for the initial detection of thoracic and abdominal lymph nodes and bone involvement. 67Ga imaging detected most cases of laryngopharyngeal disease with active inflammatory lesions found at indirect laryngoscopy. On the other hand, 67Ga scan failed to demonstrate most of the adrenal and CNS lesions detected by abdominal US/CT and head CT/MRI. In conclusion, 67Ga imaging is a useful tool for evaluating the location and extent of suspected and unsuspected lesions in PCM. It could serve as a screening method before the use of other diagnostic procedures, particularly in the detection of lung, superficial and deep lymph node and bone involvement.

Brain SPECT in dementia a clinical-scintigraphic correlation

The aim of this study was to compare the accuracy of computed tomography (CT) and single photon emission computerized tomography (SPECT) in the diagnosis of dementia. Fifty-two patients with clinical diagnosis of dementia and 11 controls were studied. The scans were interpreted by one experienced neuroradiologist and one nuclear radiologist, both blinded to the clinical data. In the diagnosis of dementia, CT and SPECT showed equal sensitivity (82.7%) and statistically similar specificity (63.8 and 81.8%, respectively). The specificity of SPECT in diagnosing Alzheimers disease (100%) was statistically superior to CT (69%). However, both methods showed similar sensitivity in detecting Alzheimers disease. In conclusion, SPECT and CT showed similar accuracy in the diagnosis of dementia. The quite high specificity of SPECT in Alzheimers disease may be useful for confirming that diagnosis, particularly for patients with presenile onset of the disease.

Brain spect in the pre-surgical evaluation of epileptic patients preliminary results

Pre-surgical evaluation of epileptic patients consists of neurological examination, intensive electroencephalographic (EEG) monitoring and anatomical studies (CT and MRI). Functional methods such as PET and SPECT imaging are now used more frequently. We have studied pre-operatively 15 adult epileptic patients (8 female, 7 male) using a rotational scintillation camera interfaced to a dedicated computer. The tomographic images were obtained 15 minutes after intravenous injection of 99mTc_HMPAO. All had MRI scanning and intensive EEG monitoring which generally included seizure recording. Five patients had progressive lesions (3 meningiomas, 2 astrocytomas). In 10 patients, neuroradiological studies did not show the presence of progressive lesions (2 normal scans and 8 cases with inactive lesions). Two patients with meningioma showed hypoperfusion at the lesion site while the third patient had a marked hyperperfusion which might correlate with the clinical diagnosis of epilepsia partialis continua. In the astrocytoma patients SPECT scans showed hypoperfusion at the lesion site. Data obtained from the 10 patients without progressive CNS lesions showed: (a) in 4, SPECT findings correlated well with the anatomical findings; (b) in 5 instances, SPECT was able to disclose additional functional deficits; (c) in one case, there was no SPECT correlate of a discrete anatomical lesion. In 5 of these cases with no progressive lesions (n=10) SPECT findings were useful as a complementary tool in determining the clinical or surgical management of these patients. Despite the small number and hete-rogenicity of the present sample, SPECT seems to be an useful tool as part of the clinical workup of epileptic patients who are candidates for epilepsy surgery.

Avaliação de atividade inflamatória na osteomielite crônica. Contribuição da cintilografia com anticorpos policlonais

BACKGROUND: Active chronic osteomyelitis or complicating osteomyelitis are difficult to be diagnosed by radiological imaging modalities, such as plain radiograph and CT. They frequently cause increased bone remodeling, leading to nonspecific uptake of Tc-99m-bone scan agents and gallium-67. New radiopharmaceuticals with greater infection avidity are being developed, including the nonspecific polyclonal immunoglobulin (IgG) labeled with technetium-99m. Tc-99m-IgG may be available as a ready to use kit, with no reported side effects, low patient absorbed radiation dose and low cost. MATERIAL AND METHODS: 23 bone segments with suspected active chronic osteomyelitis or violated bone osteomyelitis were studied by Tc-99m-IgG scintigraphy. All patients underwent standard three-phase bone scintigraphy using methylene diphosphonate (Tc-99m-MDP), gallium-67 scintigraphy and plain radiographs, compared with clinical evaluation and laboratory tests values. RESULTS: Infection was found in 8 sites. Sensitivity and specificity for Tc-99m-MDP, gallium-67 and Tc-99m-IgG scintigraphy were, respectively, 88 and 36%, 75 and 73%, 88 and 82%. CONCLUSION: Tc-99m-IgG may be usefull in the scintigraphic evaluation of osteomyelitis.OBJETIVO: O diagnostico de osteomielite cronica em atividade ou sobreposta a outras patologias e dificil, pois estas situacoes mascaram os achados radiologicos de infeccao. A especificidade da cintilografia do esqueleto ou com galio-67 tambem e reduzida pela influencia da remodelacao ossea na captacao destes radiofarmacos. Anticorpos policlonais marcados com tecnecio-99m (Tc-99m-IgG) apresentam captacao independente do metabolismo osseo, sendo um dos radiofarmacos em investigacao para avaliacao mais especifica de infeccao. CASUISTICA E METODO: Neste estudo comparou-se a cintilografia com Tc-99m-IgG, cintilografia ossea trifasica e cintilografia com galio-67 no diagnostico da osteomielite cronica em atividade em 23 segmentos osseos; correlacionando-as com dados clinico-laboratoriais e radiologicos. RESULTADOS: Oito dos 23 segmentos foram classificados como infectados, 11 nao infectados e quatro inconclusivos. A sensibilidade e especificidade encontradas para cintilografia ossea, com galio-67 e com Tc-99m-IgG foram, respectivamente, 88 e 36%, 75 e 73%, 88 e 82%. CONCLUSAO: Os resultados sugerem que a Tc-99m-IgG possa ser utilizada no diagnostico da osteomielite cronica em atividade.BACKGROUND Active chronic osteomyelitis or complicating osteomyelitis are difficult to be diagnosed by radiological imaging modalities, such as plain radiograph and CT. They frequently cause increased bone remodeling, leading to nonspecific uptake of Tc-99m-bone scan agents and gallium-67. New radiopharmaceuticals with greater infection avidity are being developed, including the nonspecific polyclonal immunoglobulin (IgG) labeled with technetium-99m. Tc-99m-IgG may be available as a ready to use kit, with no reported side effects, low patient absorbed radiation dose and low cost. MATERIAL AND METHODS 23 bone segments with suspected active chronic osteomyelitis or violated bone osteomyelitis were studied by Tc-99m-IgG scintigraphy. All patients underwent standard three-phase bone scintigraphy using methylene diphosphonate (Tc-99m-MDP), gallium-67 scintigraphy and plain radiographs, compared with clinical evaluation and laboratory tests values. RESULTS Infection was found in 8 sites. Sensitivity and specificity for Tc-99m-MDP, gallium-67 and Tc-99m-IgG scintigraphy were, respectively, 88 and 36%, 75 and 73%, 88 and 82%. CONCLUSION Tc-99m-IgG may be usefull in the scintigraphic evaluation of osteomyelitis.

Amplitude analysis of stress technetium-99m methoxy isobutylisonitrile images in coronary artery disease

To determine the role of rest and stress gated technetium-99m methoxyisobutylisonitrile (sestamibi), in the detection of coronary artery disease, routine Fourier analysis of these images was performed with the best septal left anterior oblique (LAO) position of 20 patients (17 men, 3 women; aged 40–75 years) who also underwent rest or redistribution/stress single photon emission tomography (SPET) (99mTc-sestamibi and Thallium-201), gated blood pool imaging and coronary angiogram. There were 6 patients with single-vessel disease, 6 with two-vessel disease, 4 with three-vessel disease, 2 with coronary spasms, 1 with a patent graft and 1 with anginal episodes but a normal angiogram result. Three normal volunteers (2 women, 1 man; aged 24–26 years) also had rest and stress gated blood pool as well as rest and stress gated 99mTc-sestamibi imaging. Rest and stress 99mTc-ses-tamibi amplitude and phase images depicted regional myocardial wall shortening from the outer layer of the myocardium to the center of the left ventricle as follows a high amplitude halo of maximal negative count rate variaton; a circular thinner halo of negligible amplitude; a central region of maximal positive count rate variation, as the images evolved from end-diastole to end-systole. Similar patterns with regional differences represented abnormal myocardial wall shortening. (99mTc-sestamibi and 201T1 SPET) images were in agreement in 90% of the patients and 92% of myocardial regions. 201T1 SPET detected 83% of angiographically proven lesions, as compared with 80% for 99mTc-setamibi SPET and 80% for the amplitude images. The amplitude images demonstrated a larger number of other abnormalities not predicted on the angiogram, probably because they were able to detect regions with a potential for flow improvement and transient regional wall shortening abnormalities. Amplitude and phase analyses of gated rest and stress 99mTc-ses-tamibi images are easy to perform and may become an important adjunct to (99mTc-sestamibi SPET) images for a complete evaluation of both regional myocardial perfusion and regional contractile function using a single tracer.

Avaliação experimental do atordoamento da tireóide em camundongos

OBJECTIVE: Thyroid tissue stunning after iodine-131 doses is a known cause of low uptake and unsatisfactory response to subsequent therapeutic doses. The objective of this study was to develop an experimental model of postactinic thyroid stunning. METHODS: A total of 63 mice received an equivalent dose of 45 Sv on the thyroid, by iodine-123 irradiation. This dose is similar to the estimated dose for the thyroidal remnants after administration of 185 MBq (5 mCi) of iodine-131 for whole body scans. The thyroid uptake of iodine-131 tracer doses were measured in subgroups of 9 animals, 2, 3, 5, 7, 12 and 26 days after irradiation and compared to a control group. RESULTS: The iodine uptake in the control group was 9.26%. The mean uptake value variation during the studied period was not significant. There was an increase in variance of the measures performed 5 days after irradiation, when 4 of 9 animals presented uptake 60% lower than the control group mean. CONCLUSION: There was not a systematic uptake fall in the animals submitted to the 45 Sv dose, although there was a trend for higher fluctuation in the uptake 5 days after irradiation. These findings may be due to interspecies differences or may indicate that the stunning with such doses may depend on individual characteristics or previous functional thyroid abnormalities, in addition to the radiation effect.