Technetium-99m Methoxyisobutylisonitrile Single-photon Emission Research Articles

Preoperative diagnostic value of 99mTc- MIBI SPECT/CT imaging combined with semiquantitative analysis in hyperparathyroidism and factors affecting its efficacy

To evaluate the diagnostic efficacy of technetium-99m methoxyisobutylisonitrile single photon emission/ computed tomography (99mTc- MIBI SPECT/CT), 99mTc- MIBI double- phase scintigraphy (DPS) DPS and ultrasound (US) in preoperative localization of hyperparathyroidism (HPT) and explore the factors affecting the diagnostic efficacy of 99mTc-MIBI SPECT/CT. We retrospectively analyzed the data of 104 patients with HPT undergoing surgical resection between January, 2015 and July, 2019. Preoperative 99mTc-MIBI imaging was performed in all the patients, and 82 patients also received US examination preoperatively. Semi-quantitative analysis was used to draw the region of interest and calculate the lesion/ ipsilateral deltoid muscle (T/NT) uptake ratio. The sensitivity and detection performance of 99mTc-MIBI SPECT/CT, DPS and US in the diagnosis of HPT patients were compared, and the correlations of the T/NT ratios of parathyroid adenoma (PA) and parathyroid hyperplasia (PH) with the expression levels of COX-2 and Bcl-2 were analyzed. The diagnostic sensitivity of 99mTc- MIBI SPECT/CT, DPS and US for HPT was 95.19% (99/104), 91.3% (95/104) and 81.71% (67/82), respectively, demonstrating a significantly higher diagnostic sensitivity of 99mTc-MIBI SPECT/CT than US (χ2=9.59, P=0.008). For PH lesions, 99mTc-MIBI SPECT/CT had the highest diagnostic sensitivity, followed by DPS and then by US (P < 0.05), but their sensitivity did not differ significantly for PA (P>0.05). The T/NT ratio in fatty hyperplastic glands was significantly lower than that in fat-free hyperplastic glands (P=0.009). In PA, Bcl-2 expression was significantly lower in false negative lesions than in true positive lesions (P=0.046), but Cox-2 expression did not show such a difference (P>0.05). In PH lesions, the expressions of Bcl-2 and Cox- 2 did not differ significantly between false negative than true positive lesions (P>0.05). 99mTc-MIBI SPECT/CT has a high sensitivity for HPT localization, and the T/NT ratio is positively correlated with the lesion volume. An increased expression of Bcl-2 in PA lesions and a decreased cell fat content in PH lesions can facilitate the detection of HPT glands by 99mTc-MIBI SPECT/CT.

No apparent correlation between Behçet’s disease and oxidative stress disturbance

Behçet's disease (BD) is a chronic, progressive and inflammatory multisystemic disease, that significantly affects the cardiovascular system. Oxidative stress (OS) is a disturbance in oxidant/antioxidant balance in favor of oxidants. The OS that increases acutely and chronically due to the inflammatory process plays an important role in the pathogenesis of the cardiovascular system effects of the disease by causing endothelial dysfunction in vascular structures. The aim of our study was to investigate the relationship between OS and myocardial perfusion, which is based on microvascular dysfunction, in BD. Twenty-seven patients with BD (16 M, 11 F, mean age: 38.7 +/- 9.4 years) and 22 healthy volunteers (12 M, 10 F, mean age: 35.8 +/- 6.5 years) participated in our study. Technetium-99m methoxyisobutylisonitrile single photon emission computed tomography (Tc-99m MIBI SPECT) stress-rest test was performed with two-day protocol. Myocardial perfusion scores (summed stress score, summed rest score, summed difference score, fix defect score) and perfusion defect prevalence (stress, rest, ischemic and fixed) were determined as the percentage of left ventricle. Coronary angiography was performed in patients with abnormal myocardial perfusion scintigraphy. For OS analysis, the blood samples were taken immediately before the first imaging procedure and were studied for malondialdehyde, glutathione, nitrite, nitrate, vitamin C, retinol, and carotene. In the BD group, a total of 9 patients had abnormal findings in their stress and rest electrocardiography. Perfusion defect in myocardial perfusion scintigraphy was observed in 14 patients (51.8%). Twelve patients accepted coronary angiography, and their results were normal. In the comparison of myocardial perfusion scores, perfusion defect prevalence and OS parameters, there was a significant difference between the BD and control groups. In the BD group, no correlation was observed between myocardial perfusion scores, perfusion defect prevalence and OS parameters. Defects in myocardial perfusion and increase in OS were observed in BD; however, there was no correlation between the two findings in the inactive period. In other words, the prevalence and intensity of myocardial perfusion defects can vary at different OS levels.

Usefulness of technetium-99m methoxyisobutylisonitrile single-photon emission computed tomography and computed tomography in the evaluation of cervical lymph node metastasis

The aim of this study was to compare the effectiveness of technetium-99m methoxyisobutylisonitrile ((99m)Tc-MIBI) single-photon emission computed tomography (SPECT) and computed tomography (CT) in evaluating cervical lymph node metastasis of head and neck cancer. Histopathologic results of 166 cervical lymph node levels in 31 neck-dissected patients were compared with pre-operative CT and (99m)Tc-MIBI SPECT findings about cervical lymph node metastasis, retrospectively. Sensitivity, specificity and predictability of CT and (99m)Tc-MIBI SPECT were 68.2, 93.1 and 89.8 per cent and 59.1, 87.5 and 83.7 per cent, respectively. When analysing CT and(99m)Tc-MIBI SPECT together, sensitivity and specificity were 86.4 and 99.3 per cent, respectively. The combined use of (99m)Tc-MIBI SPECT and CT could increase the accuracy of cervical lymph node metastases detection, compared with separate use of either (99m)Tc-MIBI SPECT or CT.

Effect of expression of P-glycoprotein on technetium-99m methoxyisobutylisonitrile single photon emission computed tomography of brain tumors.

The expression of P-glycoprotein was investigated immunohistochemically in 26 brain tumor tissues and compared with the findings of technetium-99m methoxyisobutylisonitrile single photon emission computed tomography (99mTc-MIBI SPECT) to clarify the effect of P-glycoprotein on the diagnostic accuracy. P-glycoprotein labeling index of both tumor cells and vascular endothelial cells showed no clear relationship with the findings of 99mTc-MIBI SPECT imaging. Expression of P-glycoprotein has no effect on the diagnostic accuracy of 99mTc-MIBI SPECT.

Correlation of ST-segment depression during ambulatory electrocardiographic monitoring with myocardial perfusion and left ventricular function

To assess the relation between silent ischemia and objective markers of ischemia we compared ambulatory electrocardiographic (AECG) monitoring, exercise stress testing, and technetium-99m methoxyisobutyl isonitrile single-photon emission computed tomography (SPECT) in 68 patients with coronary artery disease. ST-segment depression at AECG monitoring occurred in 40%, exercise testing was positive in 88%, and SPECT was abnormal in 98% of patients. Patients with ST-segment depression had a higher incidence of 3-vessel disease (70% vs 45%, p = 0.04), shorter duration of exercise (267 ± 109 vs 416 ± 167 seconds, p <0.01), lower workload achieved (5.1 ± 1.9 vs 7.6 ± 2.8 METs, p <0.0002), and a greater extent of ischemia at scintigraphy (p = 0.01). Patients with a total ischemic time of >30 minutes in a 24-hour period had a lower ejection fraction (48 ± 21% vs 70 ± 9%, p = 0.001), a higher perfusion index at rest (2.4 ± 0.6 vs 1.6 ± 0.6, p = 0.001), and a greater number of segments with fixed perfusion defects (4.1 ± 3.7 vs 1.3 ± 1.8, p = 0.02) in comparison with those who had a shorter ischemic time. We conclude that AECG monitoring fails to identify a substantial proportion of patients with objective markers of ischemia; however, ST-segment depression reflects more significant disease. Longer total ischemic time correlates with the area of myocardial damage but not with other markers of ischemia.

Myocardial perfusion and function of the systemic right ventricle in patients after atrial switch procedure for complete transposition: long-term follow-up

OBJECTIVESOur purpose was to assess the right ventricular (RV) function and identify patients with RV impairment long after the Mustard or Senning operation.BACKGROUNDSystemic ventricular failure can cause myocardial perfusion abnormalities in thallium scintigraphy correlating with hemodynamic deterioration.METHODSMyocardial perfusion at rest and at peak exercise was assessed in 61 patients, aged 7 to 23 years in mean time 10.0 ± 2.9 years after surgery using technetium-99m methoxyisobutyl isonitrile single-photon emission computed tomography. Ventricular function was assessed by first-pass radionuclide angiography at rest. Exercise capacity was determined with a modified Bruce protocol.RESULTSThe mean RV ejection fraction was 36.1 ± 7.7%, and left ventricular (LV) ejection fraction was 52.1 ± 9.4%. Moderate or severe perfusion abnormalities on the rest scan were observed in 20 patients (33%). On exercise perfusion worsened in another 13 patients (21.3%). Patients with perfusion defects on stress scan had significantly lower RV and LV ejection fraction (33.2 vs. 39.4%; p = 0.002 and 49.2 vs. 55.5%; p = 0.01, respectively). They were also older (16.6 vs.13.0 years; p = 0.002), operated on at an older age (4.0 vs. 2.4 years; p = 0.05) and had longer follow-up (12.5 vs. 10.5 years; p = 0.003).CONCLUSIONSMyocardial perfusion defects are common findings in patients in long-term follow-up after atrial switch operation. Despite excellent exercise tolerance, the extent of myocardial perfusion abnormalities correlated well with impaired RV and LV function, and greater perfusion defects were seen more frequently in older patients with longer follow-up. It is likely that myocardial perfusion defects could be a sensitive predictor of systemic ventricular impairment.

Dipyridamole administration at the end of an insufficient exercise Tc-99m MIBI SPECT improves detection of multivessel coronary artery disease in patients with previous myocardial infarction

To demonstrate that the administration of dipyridamole at the end of an insufficient maximal subjective exercise test can improve the diagnostic accuracy of single-photon emission computed tomography in patients with previous myocardial infarction, 209 consecutive patients were studied with technetium-99m methoxyisobutyl isonitrile single-photon emission computed tomography and coronary angiography. Patients were divided in 3 groups: group 1, 107 patients with sufficient exercise testing; group 2, 55 patients with insufficient exercise testing; group 3, 47 patients with insufficient exercise testing in whom intravenous dipyridamole (0.56 mg/kg over 4 minutes) was administered at the end of exercise. In groups 1 and 3 the sensitivity values for the diagnosis of multivessel disease were significantly higher (80% and 76%, respectively) than those in group 2 (59% [p = 0.009 and p = 0.02, respectively]). Specificity and predictive values were not different among the 3 groups. Thus, in patients with previous infarction in whom adequate levels of exercise could not be achieved, dipyridamole administration at the end of exercise significantly increased the sensitivity for diagnosing multivessel disease.

Specificity and sensitivity of exercise-induced st segment elevation for detection of residual viability: Comparison with fluorodeoxyglucose and positron emission tomography

We evaluated the sensitivity and specificity of exercise-induced ST segment elevation for the detection of residual myocardial viability. Assessment of residual viability after myocardial infarction is relevant for establishing indication for revascularization. We have previously shown that exercise-induced ST segment elevation is a marker of residual viability. We studied 34 patients with a previous Q wave myocardial infarction (anterior in 21, inferior in 13) of whom 18 (group A) had exercise-induced ST segment elevation in more than one lead (mean [+/- SD] 1.8 +/- 0.9 mm, range 1 to 4) and 16 (group B) did not. All patients underwent rest technetium-99m methoxyisobutyl isonitrile single-photon emission computed tomography (SPECT), fluorine-18 (F-18) fluorodeoxyglucose positron emission tomography and coronary angiography. The time elapsed between the infarction and the viability study was 72 +/- 108 days (range 15 to 400) in group A and 516 +/- 545 days (range 14 to 1,800) in group B. The presence and site of previous infarction were confirmed by SPECT studies in all 34 patients. Uptake of F-18 fluorodeoxyglucose within the infarcted area was present in 18 of 18 patients in group A but in only 9 (56%) of 16 in group B (p < 0.01). In patients with an anterior infarction, the sensitivity, specificity and predictive accuracy of exercise-induced ST segment elevation for detection of residual viability were 82%, 100% and 86%, respectively (95% confidence intervals 46% to 83.5%, 59% to 100% and 55.6% to 87.1%, respectively). Exercise-induced ST segment elevation in infarct-related leads has a high specificity and acceptable sensitivity for detection of residual viability within the infarcted area.

Dobutamine 99mTc-MIBI single-photon emission tomography: non-exercise-dependent detection of haemodynamically significant coronary artery stenoses

Dobutamine pharmacological stress testing in conjunction with technetium-99m methoxyisobutylisonitrile single-photon emission tomography (MIBI SPET) may be a useful alternative to convential exercise stress MIBI SPET for the detection and localisation of coronary artery stenoses. Therefore, 35 patients with stenoses (> or = 50% diameter reduction) of one or more coronary arteries were selected for dobutamine MIBI SPET. Each patient underwent MIBI injection at rest and during dobutamine infusion with incremental doses (5, 10, 15 and 20 micrograms kg-1 min-1). A conventional exercise stress test (EST) was performed in all patients. Peak double product during steady-state dobutamine infusion (18,200 +/- 4200 mmHg min-1) was lower (P = 0.0001) than during EST (21,700 +/- 4900 mmHg min-1). Image quality was good in all but one patient, who had to be excluded from data analysis due to excessive hepatobiliary MIBI activity. Dobutamine-induced perfusion abnormalities were observed in 30/34 MIBI SPET studies, resulting in an overall detection rate for coronary artery disease of 88%. A pathological EST was observed in 23/34 patients (68%). The detection rate of individual coronary artery stenoses was 85% (28/33) for stenosess with a severe diameter reduction (> 70%) and 50% (12/24) for stenoses with a moderate diameter reduction (> or = 50-70%). In particular, sensitivity and specificity for the detection of moderate and severe stenoses (> or = 50%) were 75%/100% for left anterior descending, 67%/95% for left circumflex and 67%/69% for right coronary artery stenoses. Dobutamine MIBI SPET is a well-tolerated, non-exercise-dependent test for detection and localisation of haemodynamically significant coronary artery stenoses.(ABSTRACT TRUNCATED AT 250 WORDS)