99mTc-MIBI Myocardial Perfusion Research Articles

Utility of 99mTc-MIBI myocardial perfusion imaging in the evaluation of cardiovascular complications in COVID-19 patients

The coronavirus disease is due to Acute Respiratory Syndrome Coronavirus2 (SARS-CoV-2). COVID-19 mainly affects the respiratory and immune systems and other organs like the cardiovascular and nervous systems, lungs, and kidneys (1). Several studies have reported COVID-19 patients with persistent symptoms for months after the initial phase. The most common symptoms are fatigue, headaches, cough, anosmia, arthralgia, and chest pain (2). Studies have shown this modality to diagnose, follow up, and evaluate response to treatment in chronic COVID-19 complications using 99mTc-MIBI myocardial perfusion single photon emission computed tomography (SPECT), pulmonary involvement with 99mTc-MAA perfusion lung scan, renal involvement with 99mTc-DTPA, and 99mTc-DMSA renal scintigraphy (3). Myocardial perfusion imaging with 99mTc-MIBI provides meaningful data to predict prognosis, risk of annual cardiac events, and evaluation of myocardium viability (4). Conventional SPECT Myocardial Perfusion Imaging (MPI) needs a viable metabolically active myocardial cell to extract the radiotracer. A review of articles shows that 99mTc-MIBI myocardial perfusion scintigraphy could be helpful in the timely acute myocardial infarction (MI) diagnosis and myocardial viability in COVID-19 patients. It is also beneficial in managing COVID-19 patients with heart failure by myocardial injury evaluation and choosing the best therapeutic choice, prognosis, and treatment response.

A Prospective Comparative Study between 99mTc MIBI Myocardial Perfusion Single-Photon Emission Computed Tomography and Dobutamine Stress Echocardiography to Detect Viable Myocardium in Patients with Coronary Artery Disease.

The objective of this study was to compare 99mTc MIBI myocardial perfusion SPECT and Dobutamine Stress Echocardiography (DSE) in detecting viable myocardium in patients with Coronary Artery Disease. Total of 50 patients who with CAD and poor LV function were idenitifed on 2D Echo using 16 segment cardiac model. These patients underwent 99mTc MIBI myocardial perfusion SPECT and Dobutamine Stress Echocardiography and the results were compared with the gold standard 18F-FDG PET-CT findings. A Total of 550 dysfunctional segments were identified in datasets of 50 patients on 2D echo. No significant difference was noted between the pairwise positive outcome of viable segment between MIBI SPECT and DSE (p=0.875). MIBI SPECT showed a sensitivity of 86.5% and specificity of 90.0% when compared with 18F-FDG PET-CT which was comparable with DSE having a sensitivity of 87.6% and specificity of 90.7%. 99mTc MIBI SPECT is an effective good alternative for evaluation of viable myocardial segments in patients with dysfunctional myocardium and can be considered especially in elderly or obese patients and patients with lung disease having poor echocardiographic imaging window due to lack of an optimal acoustic window.

Impact of intravenous administration of anisodamine on coronary microvascular dysfunction in patients with obstructive epicardial coronary artery disease after percutaneous coronary intervention

Purpose: To analyze intravenous administration of anisodamine’s impact on coronary microvasculardysfunction (CMD) in obstructive epicardial coronary artery disease (CAD) patients who had undergone percutaneous coronary intervention (PCI).Methods: Enrollment of 210 patients in Shanghai Chest Hospital, Shanghai Jiaotong University with CMD was done in a randomized-controlled study. They were divided randomly into groups, viz, anisodamine (A) group and nitrate (N) group. A 14-day course of treatment was carried out in each group. 99mTc-MIBI myocardial perfusion imaging (MPI), treadmill exercise test (TET) and two dimensional echocardiography (TDE) were performed, and the symptoms of angina pectoris were recorded before and after treatment according to the classification, frequency, and duration of angina, as defined by Canadian Cardiovascular Society (CCS).Results: After treatment, summed stress score (SSS) and summed rest score (SRS) of MPI in group A significantly decreased after treatment (p < 0.001, respectively) and were remarkably lower than those in group N (p < 0.001, respectively). The CCS class in group A improved after treatment (p < 0.001) and was also better than in group N (p < 0.001). The frequency and duration of angina attack in group A significantly reduced after treatment (p < 0.001, respectively) and were notably lower than in group N (p < 0.001, respectively). Left ventricular ejection fraction in group A after treatment was higher than that before treatment (p = 0.046) and than that in group N (p = 0.048). Furthermore, the side effects of anisodamine were slight and tolerable.Conclusion: Intravenous administration of anisodamine is a potentially suitable optional treatment for CMD in patients with obstructive epicardial CAD who have undergone PCI.

Serendipitous detection of hiatus hernia due to stomach wall tracer uptake on 99mTc-MIBI myocardial perfusion imaging

Serendipitous detection of hiatus hernia due to stomach wall tracer uptake on 99mTc-MIBI myocardial perfusion imaging

Radiomics analysis of myocardial perfusion SPECT images in patients with cardiomyopathy and heart failure

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): JSPS KAKENHI Grants Background Although myocardial perfusion heterogeneity due to focally damaged cardiomyocytes is observed in single−photon emission computed tomography (SPECT) imaging, a current perfusion defect scoring system does not allow us to provide sufficient diagnostic information for heterogeneity. Purpose The aim of this study was to perform radiomics analysis of myocardial perfusion SPECT (MPS) images to investigate the potential to detect myocardial perfusion heterogeneity. Methods Patients with hypertrophic cardiomyopathy (n = 3), heart failure (n = 9), and with a low likelihood of coronary artery disease (n =15) (Figure 1), who underwent a rest 99mTc-MIBI myocardial perfusion SPECT, were assessed using a LIFEx software. Four shape−based features, 6 histogram−based features, and 32 textural features were computed. The relevant features for the classification of the patients were selected using the Boruta algorithm, and hierarchical clustering of the selected features using the Spearman correlation coefficient was also performed for the feature reduction. The receiver operating characteristics (ROC) analysis was performed by the support vector machine to calculate the area under the ROC curve (AUC) for the selected features. Results Of 40 features, 17 were selected by the classification analysis, and these features were classified into 7 classes by the correlation analysis (Figure 2). The ROC AUCs for 7 features extracted from each class were 0.99, 0.97, 0.96, 0.92, 0.90, 0.86, and 0.83 for the contrast of NDGLDM, the entropy of histogram, ZLNU of GLZLM, the energy of GLCM, the energy of histogram, SZLGE of GLZLM, and the correlation of GLCM, respectively, as compared to 0.39 for a summed rest score. Conclusions Radiomics analysis successfully determined the myocardial perfusion heterogeneity in patients with cardiomyopathy and heart failure. It might be promising for the evaluation of myocardial damages that cannot be analyzed by the conventional scoring method.

Could heart rate recovery and exercise capacity predict abnormal 99mTc-MIBI myocardial perfusion scan findings?

Background and aim: Ischemic heart diseases lead to numerous deaths worldwide. Prevention, rapid diagnosis and treatment are principal strategies in controlling mortality due to coronary artery diseases (CAD). Considering variety of options, finding suitable diagnostic modality for each patient has been controversial for long times. Exercise treadmill test (ETT) is a well-known and old modality compared to radionuclide scintigraphy. In this study we aimed to assess if heart rate recovery (HRR) and exercise capacity (EC) in ETT can predict perfusion defects in 99mTc-MIBI SPECT myocardial perfusion imaging (MPI).Materials and methods: In this cross-sectional, descriptive-analytic study, we enrolled 254 patients referred for MPI to nuclear medicine department of Afshar or Shahid Sadoughi Hospital, Yazd, Iran. All patients underwent ETT and MPI. HRR and EC in ETT plus abnormal perfusion findings in MPI along with patient’s history and demographic information were recorded in a questionnaire. Finally, all data were analyzed using SPSS ver.22 software.Results: Based on our results, 161 (63.4%) of patients were men. Half of patients were diagnosed with hypertension. 45% were diagnosed with diabetes, 41% had hyperlipidemia and 8.3% were smokers. Based on our findings, 18.1% of patients had abnormal MPI results. Our analytic results indicated that there is no statistically significant association between transient RV visualization, transient ischemic dilation or lung to heart ratio with 1st and 2nd minute HRR and EC.Conclusion: Considering lack of association between ETT indices and MPI findings, it seems that ETT is not adequately sensitive in predicting perfusion defects in MPI. Thus, it seems logical in some cases to ignore expenses of MPI and suggest it to patients before ETT based on clinical judgement.

The Ability of Quantitative Data Evaluated by 99m Tc-MIBI Myocardial Perfusion Scintigraphy to Predict Coronary Artery Disease

Objective:
 Although the efficacy of the visual interpretation of 99mTc-MIBI myocardial perfusion imaging has been repeatedly confirmed in the diagnostic and prognostic evaluation of coronary artery disease (CAD), the efficacy of the automated quantitative evaluation dependent on computer programs is controversial. In our study, we compared automated quantitative data, such as the sum stress score (SSS) and the sum difference score (SDS), with coronary angiography results. We investigated the ability of SSS and SDS values to predict coronary artery disease.
 Method:
 SSS and SDS are measurements used in the global scoring of myocardial perfusion. While SSS indicates the degree of ischemia, SDS defines the reversibility degree of ischemia. In the global scoring of myocardial perfusion, when the SSS was 4 and above, MPI was evaluated as positive. In the coronary angiography, a stenosis value of >50% was evaluated as positive. We divided the SSS into three groups; mild (4-8), moderate (9-12), and advanced (>13) hypoperfusion. We divided the SDS into two groups as below and above 10%. We compared the subsequent quantitative data with the results of the three groups of coronary angiographies (70% stenosis). 
 Results: 
 A total of 104 patients who underwent angiography were included in the study. The accuracy in detecting positivity between the general quantitative MPI and angiography methods of the patients was calculated as 80.8%. The agreement value was found to be significant (Kappa=0.602; p

Association of use of proton pump inhibitors and H2 antagonists with stomach wall uptake in 99mTc-methoxy-isobutyl-isonitrile (MIBI) myocardial perfusion imaging

BackgroundStomach wall uptake (SWU) of tracer in 99mTc-MIBI myocardial perfusion imaging (MPI) occasionally leads to imaging artifacts, thereby lowering the diagnostic accuracy. It is less-studied phenomenon for possible link with proton pump inhibitors (PPIs) intake. This prospective work looked for association of SWU with PPI intake and compared its incidence with H2 antagonists (H2A) users and patients not on either gastroprotective medication. MethodsOne hundred fifty-six patients undergoing one day stress/rest 99mTc-MIBI SPECT-MPI were distributed into four groups: control group (n = 48, not on any gastroprotective medication), PPI group (n = 47, on PPI treatment), H2A group (n = 19, on H2A therapy), and intervention group (N = 42, PPI discontinued for 3 days before MPI). Poststress planar images were analyzed for clinically relevant SWU. ResultsClinically relevant SWU was seen in 36% of PPI group patients compared to 8% in the control group, 10.5% in the H2A group, and 9.5% in the intervention group, respectively, with statistically significant difference. Only 1/40 patients undergoing exercise stress showed clinically relevant SWU compared to 26/116 patients undergoing adenosine stress (P = .020). ConclusionPatients on PPIs scheduled for vasodilator stress MPI may discontinue PPIs for 3 days, or replace with H2A to reduce the incidence of clinically relevant SWU associated with PPI therapy.

The levels of oxidative and nitrosative stress in patients who had 99mTc-MIBI myocardial perfusion scintigraphy and 99mTc-DMSA, 99mTc-MAG-3 renal scintigraphy.

Ionizing radiation is a strong stimulator of reactive oxygen specises (ROS) and reactive nitrogen species (RNS). These reactive species may cause oxidative and nitrosative stress. In this study, we aimed to evaluate possible effects of 99mTechnetium (99mTc)-methoxyisobuthylisonitrite (MIBI), 99mTc-dimercaptosuccinic acid (DMSA), 99mTc-mercaptoacetyltriglycine (MAG-3) on oxidative and nitrosative stress biomarkers in patients who were performed myocardial perfusion scintigraphy (MPS) and renal scintigraphy. Patients (n = 29) who were referred to nuclear medicine department were chosen as the patient group. They were divided into three subgroups according to the type of disease and 99mTc labelled agent. The first patient group had MPS (n = 9). The second patient group had 99mTc-DMSA renal scintigraphy (n = 12). The third patient group had 99mTc-MAG-3 renal scintigraphy (n = 8). The blood samples were taken from first, second and third patient groups 1 h, 3 h, 45 min after injection of the agent, respectively. The samples were taken from healthy volunteers (n = 25) as a control group. Alterations in catalase (CAT),superoxide dismutase (SOD), malondialdehyde (MDA) levels as oxidative stress biomarkers and nitric oxide (NO) and 3-Nitrotyrosine (3-NTx) levels as nitrosative stress biomarkers in all blood samples were evaluated. Results of MPS and renal scintigraphy performed patients were compared with control group separately. CAT, SOD, MDA and 3-NTx levels were higher in the first group than the control group (p < 0.05). Although NO levels were higher in the first group than the control group, it was not statistically significant (p > 0.05). CAT and SOD levels were lower in second and third groups than the control group (p < 0.0 5). However, MDA, NO, 3-NTx levels were higher in second and third groups than the control group (p < 0.05). These results show that oxidative and nitrosative balance is impaired due to ionization radiation. These reactive species might stimulate an adaptive and protective cellular defense mechanism in irradiated cells soon after exposure to radiation. Thereby, this mechanism protect organism from the effects of low dose ionizing radiation.

Assessment of Organ Doses for Patients undergoing 99mTc-MIBI Myocardial Perfusion Imaging.

Radiation absorbed doses associated with myocardial perfusion imaging (MPI) using 99mTc-MIBI has been determined at the Radioisotopes Institute of the Abdou Moumouni University. Thirty patients undergoing MPI were scanned and image quantification was done using Mediso Inter View XP® software. The average administrated activities of 99mTc-Sestamibi were 370 MBq (10 mCi) in stress condition and 1110 MBq (30 mCi) in rest condition with one day protocol. The radionuclide activities in the heart, liver, kidneys and urinary bladder were determined using the conjugate view method. The uptake of 99mTc-MIBI in the heart, liver and kidneys were respectively about 2.17% ±0.64, 6.53% ±1.47 and 5% ±0.52, 10 minutes after injection. The cumulative activities for the heart, liver, kidneys and urinary bladder were respectively 21.97 MBq.h, 63.11 MBq.h, 36.61 MBq.h, 79.48 MBq.h for the stress and 68.23 MBq.h, 239.79 MBq.h, 101.69 MBq.h and 223.1 MBq.hin the rest conditions. The organs absorbed doses in this study were 3.06 mGy for kidneys, 0.75 mGy for liver, 0.75 mGy for the heart, and 20.46mGy for bladder.

Thymoma as an Incidental Finding in a Myocardial Perfusion Study with 99mTc-MIBI

Myocardial perfusion imaging is a nuclear medicine imaging technique that allows to make an approach to the coronary condition in patients with moderate probability to have coronary artery disease. 99mTc MIBI myocardial perfusion is one of the most common techniques in nuclear medicine clinical practice. Extracardiac accumulation of the tracer is relatively common, and can be seen in certain tumors with high metabolic rate, due to the radiotracer’s mitochondrial preference. We present a case report of an unusual finding in a myocardial perfusion scan related to an abnormal uptake of the radiotracer in a mediastinal mass which was consistent with thymoma.

Myocardial Perfusion Abnormalities in Young and Premenopausal Women with Systemic Lupus Erythematosus, Detected with 99MTC MIBI Myocardial Perfusion Scintigraphy - Prevalence and Correlation with Proatherogenic Factors.

Atherosclerosis in young and premenopausal women with systemic lupus erythematosus (SLE) is frequent, premature and progressive. Although asymptomatic or with atypical clinical presentation, the patients are at high risk of cardiac events. Aim of this study is to estimate the risk profile for atherogenesis and the prevalence of myocardial perfusion abnormalities with 99mTc myocardial perfusion scintigraphy (MPS) in young and premenopausal women. Sixty female patients, aged 30-72 years (divided into two subgroups - patients under 45 years of age and patients over 45 years), diagnosed with SLE for over of 5 years, in active phase of the disease were analyzed for disease activity scores (SLEDAI), the immunologic status of the disease (ANA and a-DNA antibodies in the serum), procoagulant tendency (antiphospholipid antibodies-APhL and lupus-anticoagulant-LAC), the activity of the inflammatory process (hsCRP), the anti-SLE therapeutic approach and the presence of traditional risk factors for atherosclerosis (BMI, smoking, hypertension, hyperlipidemia, diabetes, and familial history for the CAD). Using one-day Dipyridamol - Rest 99mTc SPECT Gated MPS SPECT the extent, severity and reversibility of myocardial perfusion abnormalities were estimated, along with summed scores at stress, rest and summed difference scores and left ventricle volumes and ejection fraction. Abnormal MPS SPECT were detected in 27/60 or in 45% of patients, with one vessel affection of 66.7% (18/27pts) of LAD and 14.8% (4/27pts) o RCA and with two vessel disease of LAD/RCA in 2/27 pts (7.4%) and LAD/Cx in 3/27pts (11.1%). Myocardial perfusion abnormalities were equally prevalent in subgroups of patients younger than 45 years (44,4%) and in patients older than 45 years (45.5%) (ns). The subgroups did not differ significantly concerning the extent of perfusion abnormalities (9,8±3.2% of LV myocardial mass vs. 9,8±7.1%,ns), their severity (with predominance of mild perfusion defects, 48,6% vs. 51,3%,ns) and reversibility (reversible in 41.3% and 58.6%, ns). The differences between the summed scores of severity and the extent of ischemia in the two subgroups were statistically nonsignificant. Younger patients had significantly higher end-diastolic, end-systolic and stroke volumes during stress and rest conditions, compared to older patients (p<0,01) although there were no differences in systolic function, which was not affected in either of the groups as expressed threw ejection fraction. Although nonsignificant, younger patients had higher values of hsCRP and higher procoagulant activity (positive aPhL, LAC) while they were with more active disease activity, with higher SLEDAI score compared to older patients (p=0.028). Higher SLEDAI score and LV volumes, especially EDV at stress were identified as predictor of abnormal MPS in younger groups and more aggressive multidrug anti SLE treatment as predictor of normal MPS. The prevalence and characteristics of myocardial perfusion abnormalities in young SLE are equal as the same in older SLE patients, which indicates the presence of premature, accelerated atherosclerosis in young cohort of patients with SLE. Younger SLE patients with pure disease control (higher SLEDAI score, less aggressive treatment, high hsCRP values and pronounced procoagulant tendency) should undergo screening for myocardial perfusion abnormalities s using 99mTc MIBI MPS).

The Value of Added CT-based Attenuation Correction Technique in the Era of Contemporary High Technology Gated 99mTc-MIBI Myocardial Perfusion Scintigraphy.

The Value of Added CT-based Attenuation Correction Technique in the Era of Contemporary High Technology Gated 99mTc-MIBI Myocardial Perfusion Scintigraphy.

DNA double-strand breaks in blood lymphocytes induced by two-day 99mTc-MIBI myocardial perfusion scintigraphy.

To investigate DNA double-strand breaks (DSBs) in blood lymphocytes induced by two-day 99mTc-MIBI myocardial perfusion scintigraphy (MPS) using y-H2AX immunofluorescence microscopy and to correlate the results with 99mTc activity in blood samples. Eleven patients who underwent two-day MPS were included. DSB blood sampling was performed before and 5min, 1h and 24h after the first and second radiotracer injections. 99mTc activity was measured in each blood sample. For immunofluorescence microscopy, distinct foci representing DSBs were quantified in lymphocytes after staining for the phosphorylated histone variant y-H2AX. The 99mTc-MIBI activity measured on days one and two was similar (254±25 and 258±27 MBq; p=0.594). Compared with baseline DSB foci (0.09±0.05/cell), a significant increase was found at 5min (0.19±0.04/cell) and 1h (0.18±0.04/cell) after the first injection and at 5min and 1h after the second injection (0.21±0.03 and 0.19±0.04/cell, respectively; p=0.003 for both). At 24h after the first and second injections, the number of DSB foci had returned to baseline (0.06±0.02 and 0.12±0.05/cell, respectively). 99mTc activity levels in peripheral blood samples correlated well with DSB counts (r=0.451). DSB counts reflect 99mTc-MIBI activity after injection for two-day MPS, and might allow individual monitoring of biological effects of cardiac nuclear imaging. • Myocardial perfusion scintigraphy using 99mTc induces time-dependent double-strand breaks (DSBs) • γ-H2AX immunofluorescence microscopy shows DSB as an early response to radiotracer injection • Activity measurements of 99mTc correlate well with detected DSB • DSB foci induced by 99mTc return to baseline 24h after radiotracer injection.

The prognostic signifi cance of normal technetium-99m MIBI myocardial perfusion spect imaging over a four-year follow-up period

normal Tc-99m MIBI myocardial perfusion study has previously been shown to indicate a benign prognosis. Our aim was to determine the longer term prognosis of a normal study in our patient population. Methods: A retrospective evaluation of 209 patients with a normal Tc-99m MIBI study was performed. Follow-up data was obtained in 157 patients, with complete follow-up in 121 (mean follow-up period of 56 months). In 36 patients only partial follow-up was possible (32 months follow-up). No follow-up data, except for the possible registration of deaths, could be obtained in 52. Patients were evaluated for the occurrence of primary or secondary cardiac events. Results: The study group had a moderate pre-test probability for coronary artery disease (48 + 30.7%). Two possible cardiac deaths occurred (cardiac death rate of 0.95%). No primary events occurred in the group with complete follow-up, but 6 secondary events were recorded (cardiac event rate of 4.9%). No primary or secondary events occurred in the partial follow-up group during the follow-up period. The incidence of secondary or non-fatal primary events in this group for the period after they were lost to follow-up or in the group with no follow-up could not be ascertained. There was, however, no statistically significant difference between these groups regarding age, pre-test probability and exercise parameters. Conclusion: Similar to the findings with Tl-201, our study indicates a favourable longer term prognosis after a normal Tc-99m MIBI study.

Detection of Thymoma on 99mTc MIBI Scintigraphy: Revisiting the Past.

Although thymoma is a rare tumor, it is the most common anterior mediastinal tumor, usually affecting the adults in their fifth and sixth decade. We present a case of 68-year-old man with history of myocardial infarction, who presented to the cardiology OPD with recent onset of exertional dyspnea. On 99mTc MIBI myocardial perfusion SPECT, there was an extra cardiac accumulation of radiotracer in the anterior mediastinum just above the heart, which later was diagnosed as thymoma on histopathology.

Impact of basal inferolateral scar burden determined by automatic analysis of 99mTc-MIBI myocardial perfusion SPECT on the long-term prognosis of cardiac resynchronization therapy.

Left-ventricular (LV) scarring may be associated with a poor response to cardiac resynchronization therapy (CRT). The automatic analysis of myocardial perfusion single-photon emission computed tomography (MP-SPECT) may provide objective quantification of LV scarring. We investigated the impact of LV scarring determined by an automatic analysis of MP-SPECT on short-term LV volume response as well as long-term outcome. We studied consecutive 51 patients who were eligible to undergo 99mTc-MIBI MP-SPECT both at baseline and 6 months after CRT (ischaemic cardiomyopathies 31%). Quantitative perfusion SPECT was used to evaluate the defect extent (an index of global scarring) and the LV 17-segment regional uptake ratio (an inverse index of regional scar burden). The primary outcome was the composite of overall mortality or first hospitalization for worsening heart failure. A high global scar burden and a low mid/basal inferolateral regional uptake ratio were associated with volume non-responders to CRT at 6 months. The basal inferolateral regional uptake ratio remained as a predictor of volume non-response after adjusting for the type of cardiomyopathy. During a median follow-up of 36.1 months, the outcome occurred in 28 patients. The patients with a low basal inferolateral regional uptake ratio with a cutoff value of 57% showed poor prognosis (log-rank P= 0.006). The scarring determined by automatic analysis of MP-SPECT images may predict a poor response to CRT regardless of the pathogenesis of cardiomyopathy. The basal inferolateral scar burden in particular may have an adverse impact on long-term prognosis.

Incidental Detection of Thyroid Neoplasm on 99mTc-SestaMIBI Myocardial Perfusion Scan - A Novel Tumour Tracer Revisted

We report a case of a young Indian male who had an incidental abnormal focal uptake of 99mTechnetium-MIBI (Methoxy Isobutyl Isonitrile) in the right lobe of thyroid while undergoing 99mTc-MIBI myocardial perfusion gated SPECT (Single Photon Emission Computed Tomography) imaging as a part of his myocardial ischemia status evaluation. This focal uptake was eventually detected to be a malignant thyroid nodule for which he underwent total thyroidectomy. His biopsy was reported as Hurthe cell nodule. Though incidental detection of thyroid, breast and lung malignant pathology on 99mTc- MIBI myocardial perfusion scans is well known, this case is a reminder and exemplifies the potential of 99mTc-MIBI not only as an excellent myocardial perfusion agent but also as a non specific tumour tracer (for its larger usage as a tracer for neoplastic survey).

The Value of Tc-99m MIBI Washout Rate in Detection of Ischemia compared with standard Myocardial Perfusion Imaging

Objective: we aimed to estimate the rate of MIBI washout of myocardium in patients with clinical ischemia as compared to the degree of reversibility between stress and rest studies.Patients and methods: this prospective study included 50 patients [34 males (60%) & 16 females (40 %)] with mean age 55.3 ± 10.1 years. All patients underwent ECG-gated SPECT Tc-99m MIBI myocardial perfusion imaging. Two days protocol (rest/stress) was used, the rest study was performed at 90 min and delayed images at 4 hours post-injection. While in stress phase images were performed after 30 min. The polar map of perfusion images acquired at stress and rest images at 90 min to detect reversibility. Also, polar map of 90 min was compared with delayed perfusion images at 4 h to calculate washout rate.Results: there was higher WR in the ischemic myocardial region of LAD (21.18±7.2) compared to the normal one (9.96±2.49), (p < 0.001). Also, in the region of RCA WR was 19.17±3.86 in ischemic wall versus 9.59±1.69 in normal walls (p<0.02) and (LCX) WR was 17.02 ± 2.6 in ischemic wall versus 9.63 ± 1.76 in normal walls (p<0.04). Additionally, the linear correlation of regional WR of each vascular territory was compared with the corresponding degree of reversibility with statistically significant for LAD (0.77), LCx (0.86) and RCA (0.64).Conclusion: There is higher WR of MIBI in ischemic walls in all vascular territories with significant correlation with its degree of reversibility that may potentiate the results of stress study.

Association of hemodynamic response during dipyridamole stress testing with 99mTc-MIBI SPET myocardial perfusion image findings.

The aim of this study was to assess whether there is an association between changes in the heart rate and blood pressure after dipyridamole stress and abnormal scan findings detected with gated technetium-99m methoxy isobutylisonitrile (99mTc-MIBI) myocardial perfusion imaging (MPI). A total of 200 consecutive patients with known or suspected coronary artery disease underwent MPI using a 2 days stress/rest protocol. Heart rate (HR), blood pressure and electrocardiogram were monitored during the stress study. Dipyridamole-induced increase in HR ratio (peak HR/baseline HR) of more than 1.20 and decrease in systolic blood pressure (SBP) of 10 mmHg or more were defined as a normal response. Low ejection fraction (EF) was defined as EF less than 45%. Semi-quantitative measures used include summed stress score (SSS), summed difference score (SDS), end systolic volume (ESV) and left ventricular ejection fraction (LVEF). Chi-square-and regression analysis was used to assess associations between the various hemodynamic parameters and MPI abnormalities. Our results showed that 75% of patients had abnormal scans. Statistically significant associations were observed between each of the following factors and abnormal scan findings: abnormal SBP response to dipyridamole (P=0.011), increased SSS (P=0.040) and low LVEF (P=0.012). A significant association was also observed between decreased HR response and low LVEF (P=0.012). In conclusion, this study demonstrated that an abnormal hemodynamic response during dipyridamole stress test was associated with abnormal myocardial perfusion imaging scan findings, low LVEF and SSS.