Prediction of Histologic Grade and Multidrug Resistance of Brain Tumors Using Brain SPECT

OBJECTIVE: Computerized tomography(CT) and magnetic resonance imaging(MRI) are very useful in detection of structural change in the brain including tumors. However, they can not inform functional and biological behavior of such lesions. 99m Tc-Methoxyisobutyl isonitrile(MIBI) is considered as a substrate for MDR1 gene-encoded permeability glycoprotein(P-gp) and it has been used in the evaluation of multidrug resistance(MDR) in various tumors. The purpose of the study is to demonstrate the presence of MDR in brain tumor and brain tumor grading by an external imaging with 201Thallium and 99m Tc-MIBI SPECT. METHODS: 201Thallium and 99m Tc-MIBI SPECT were performed in 18 patients with malignant tumors and in six patients with benign tumors. Immunohistochemical staining(IHC) of the tumor specimen for P-gp was also performed. The histologic grading of the tumors and immunohistochemical staining for P-gp were compared to the dual brain SPECT findings of 201Thallium and 99m Tc-MIBI SPECT studies. Brain tumor with positive 201Thallium SPECT and negative 99m Tc-MIBI SPECT is considered to be multidrug resistance. An uptake index obtained from brain SPECT was used for tumor grading. MDR1 gene-encoded P-gp was assessed by immunohistochemical staining using a monoclonal antibody for P-gp. RESULTS: The malignant group showed significantly higher uptake indices in the 201Thallium and 99m Tc-MIBI SPECT than benign group. The uptake index of 99m Tc-MIBI SPECT was inversely correlated with P-gp immunohistochemical staining without statistical significance. CONCLUSION: 201Thallium and 99m Tc-MIBI SPECT are useful for predicting histologic grade of brain tumors, and 99m Tc-MIBI SPECT might be useful for predicting the presence of MDR protein.

The Value of (99m) Tc-MIBI-Heart SPECT in Myocardial Contusion

PURPOSE: This study analyzed the value of (99m)Tc - M I B I SPECT(Single Photon Emission Com-puted Tomography) in the diagnosis of myocardial contusion after blunt chest trauma . METHODS: We evaluated 24 patients with cardiac contusions after blunt chest trauma who were diagnosed by clinical symptoms, chest x-ray, electrocardiogram(ECG), and Creatine phospho-kinase(CPK). (99m)Tc-MIBI SPECT was performed within 48 hours along with the above tests prospectively. RESULTS: 1. Among the 24 patients, 14 patients were finally diagnosed as having a myocardial contusion by means of ECG, echocardiography, (99m)Tc-MIBI SPECT, and cardiac enzyme. 2. The sensitivity, specificity and accuracy of (99m)Tc - MIBI SPECT were 46.7%, 66.7%, and 54.2%, respectively. The same results for initial ECG were 46.6%, 88.9%, and 62.5%. 3. For those who had positive findings in (99m)Tc - MIBI SPECT, average hospital stay was 14.5 days and abnormal electrocardiogram was found in 90.0%. However, for those who had negative findings, average hospital stay was 11.2 days and abnormal electrocardiogram was found in 35.7%. CONCLUSION: (99m)Tc-MIBI SPECT is not a definite modality in diagnosing myocardial contusion, but can be useful in diagnosing and determining the need for hospitalization after cardiac contusion.

The Value of (99m) Tc-MIBI-Heart SPECT in Myocardial Contusion

PURPOSE: This study analyzed the value of (99m)Tc - M I B I SPECT(Single Photon Emission Com-puted Tomography) in the diagnosis of myocardial contusion after blunt chest trauma . METHODS: We evaluated 24 patients with cardiac contusions after blunt chest trauma who were diagnosed by clinical symptoms, chest x-ray, electrocardiogram(ECG), and Creatine phospho-kinase(CPK). (99m)Tc-MIBI SPECT was performed within 48 hours along with the above tests prospectively. RESULTS: 1. Among the 24 patients, 14 patients were finally diagnosed as having a myocardial contusion by means of ECG, echocardiography, (99m)Tc-MIBI SPECT, and cardiac enzyme. 2. The sensitivity, specificity and accuracy of (99m)Tc - MIBI SPECT were 46.7%, 66.7%, and 54.2%, respectively. The same results for initial ECG were 46.6%, 88.9%, and 62.5%. 3. For those who had positive findings in (99m)Tc - MIBI SPECT, average hospital stay was 14.5 days and abnormal electrocardiogram was found in 90.0%. However, for those who had negative findings, average hospital stay was 11.2 days and abnormal electrocardiogram was found in 35.7%. CONCLUSION: (99m)Tc-MIBI SPECT is not a definite modality in diagnosing myocardial contusion, but can be useful in diagnosing and determining the need for hospitalization after cardiac contusion.

Technetium-99m-MIBI SPECT in Intracranial Lesions

Thallium(T1) has recently been used as a pharmaceutical for tumor imaging and staging. The aim of this study was to evaluate the clinical significance of the T1 analogue, 99m-Tc-MIBI(methoxyisobutylisonitrile), for imaging of intracranial lesions. The advantages of MIBI were though to be a lower radiation exposure and better image quality than with T1. 99m-Tc-MIBI SPECT studies were done in 30 patients with brain tumors(14 astrocytomas, 7 meningiomas, 2 hemangioblastomas, 2 craniopharyngiomas, 1 ependymoma, 4 metastatic tumors) and in twelve patients with non-tumorous lesions(2 abscesses, 2 granulomas, 2 cysticercosis, 3 old intracerebral hemorrages, 1 infarction. 1 postoperative gliosis, 1 unknown pathology), and semiquantitative assessment of tracer uptake was made using a ratio of radioactivity for lesion to contralateral normal brain(Lesion/Contralateral normal brains ; L/C). Twenty six of thirty tumors showed high L/C ratios(>1.5) and another four tumors low L/C ratios(<1.5). Of 12 non-tumorous intracranial lesions, 11 showed little or no uptake, but one moderate uptake. In conclusion, it appears that brain tumors show more intense focal uptake than non-tumorous brain lesions. However, further studies would be warranted to evaluate the clinical significance of MIBI SPECT in tumor staging(grading) and in differentiating necrosis from tumor regrowth more clearly.

A Case of Giant Coronary Arteriovenous Fistula with Coronary Steal Demonstrated by Dobutamine Stress Echocardiography and (99m)Tc-MIBI SPECT

We present a case of giant coronary arteriovenous fistula between left main coronary artery and pulmonary artery in a 60-year-old female who presented with anginal symptom. Dobutamine stress echocardiography and myocardial perfusion scan with (99m)Tc-MIBI revealed a reversible perfusion defect in the septal region. Coronary angiography demonstrated a giant coronary arteriovenous fistula origination from the left main coronary artery and draining into the pulmonary artery. This appears to be the first case in which dobutamine stress echocardiography and myocardial perfusion scan with (99m)Tc-MIBI demonstrated myocardial ischemia due to coronary steal in patient with a coronary arteriovenous fistula.

(99m)Tc-MIBI SPECT Findings in Diabetics with Coronary Artery Disease

BACKGROUND: Evaluation of coronary artery disease(CAD) by radionuclide myocardial perfusion scintigraphy is safe, convenient and informative for diagnosis of CAD & assessment of functional significance of stenotic lesions. We tried to evaluate the characteristics of CAD in dibetics by intravenous dipyridamloe (99m)Tc-MIBI(methoxy isobutyl isonitrile) SPECT(Single Photon Emission Computed Tomography). METHOD: (99m)Tc-MIBI SPECT and coronary arteriography(CAG) were performed simultaneously in less than 2 week interval in 41 diabetics(diabetic group) and 103 non-diabetics(non-diabetic group) with clinical suspicion of CAD. The sensitivity and specificity of (99m)Tc-MIBI SPECT for detection of CAD were compared between two groups. The site and number of involved vessels, the extent of perfusion defect and redistribution pattern were compared between two groups. RESULT: 1) The sensitivity and specificity of (99m)Tc-MIBI SPECT for detection of CAD were 97% and 80% in diabetics, these were comparable to those in non-diabetics(97% and 78%). 2) Three vessel disease were common(p<0.01)in diabetics(SPECT 28.1%, CAG 32.3%) than in non-diabetics(SPECT 11.4%, CAG 7.5%). Distal lesions were also more common(p<0.005) in diabetics(CAG 40.3%) than in non-diabetics(CAG 15.7%). 3) On stress SPECT, the extent of perfusion defect was not different in individual vessel areas between diabetics and non-diabetics. However the perfusion defect of left ventricle as a whole was significantly higher(p<0.05) in diabetics(35.2+/-16.2%) than in non-diabetics(26.4+/-15.5%). 4) On rest SPECT, the percent redistribution was significantly lower in diabetics than in non-diabetics(left anterior descending artery area ; diabetic group 31.1+/-22.5% vs non-diabetic group ; 49+/-28.5%, p<0.05, left ventricle as a whole ; diabetic group 30.6+/-21.2% vs non-diabetic group 48.2+/-27.6%, p<0.02). CONCLUSION: Quantitative (99m)Tc-MIBI SPECT provided high sensitivity and specificity for detection of CAD in diabetics. Multiple vessel disease, distal lesion and fixed lesions were more common in diabetics than in non-diabetics, (99m)Tc-MIBI SPECT is useful noninvasive test for diagnosis of CAD & important prognostic implications.