Evaluation of Left Ventricle Performance in Patients with Ischemic Heart Disease Using Single Photon Emission Computed Tomography (SPECT) in Comparison with Echocardiography

Background: Ischemic heart disease is a major cause of the diastolic heart failure. Risk of heart failures was increased with microvascular coronary disease, which is characterized by left ventricular stiffness with impaired relaxation and reduced compliance. Aim of this study is to estimate the effect of the severity of myocardium ischemia on the left ventricle ejection fraction and left ventricular volume using SPECT with 99mTc MIBI and to compare the results with the echocardiography. The study included 117 subjects with ischemic heart disease were examined using SPECT and echocardiography techniques. The following parameters were measured: left ventricular end systolic volume (LVESV) , left ventricular end diastolic volume (LVEDV) , and left ventricular ejection fraction (LVEF). Results show that the change difference in EDV between the two technique was (98.79%) with insignificant (p > 0.05). While the change in the LVEF% between both groups was (105.40%) with significant (p <0.05). On the other hand, the difference in ESV and EDV/ESV ratio for both groups were (95.52%), and (103.61%) respectively with insignificant (p >0.05). It was concluded that SPECT with 99mTc MIBI had a good relation with the echocardiography technique for evaluation of the left ventricular ejection fraction and the left ventricular volumes. The results showed that LVEF was decreased in patients with severe ischemic disease.

Utility of 99mTc-sestamibi Heart/Liver uptake ratio in Screening Non-alcoholic Fatty Liver Disease during Myocardial Perfusion Imaging

Purpose Non-alcoholic fatty liver disease (NAFLD) is the most common chronic hepatic disease worldwide with functional impairment of the mitochondria occurring from early stages. Technetium-99m methoxy-isobutyl-isonitrile (99mTc-MIBI) is a lipophilic agent trapped in the mitochondria. This study aims to evaluate the utility of 99mTc-MIBI heart/liver uptake ratio in screening for NAFLD during myocardial perfusion imaging (MPI). Methods 70eligible patients underwent a two-day rest/stress 99mTc-MIBI scan with a 2-minute planar image acquired in rest phase, at 30, 60 and 120 minutes post radiotracer administration. Heart/liver uptake ratio was calculated by placing identical regions of interest on the heart and liver dome. All patients underwent liver ultrasound and were allocated into groups A, having NAFLD, and B, healthy individuals without NAFLD. Results Mean count per pixel heart/liver ratios gradually increased over time in either groups; nonetheless the values were significantly higher in group A, regardless of acquisition timing; with the P-value equal to 0.007, 0.014 and 0.010 at 30, 60 and 120 minutes, respectively. Conclusions Determining 99mTc-MIBI heart/liver uptake ratio during rest phase in patients undergoing MPI may be a useful, non-invasive screening method for NAFLD; with no additional cost, radiation burden or adverse effects in these patients.

Inter- and Intraobserver Repeatability of Myocardial Flow Reserve Values Determined with SPECT Study Using a Discovery NM530c Camera and Corridor 4DM Software

Background: Myocardial blood flow (MBF) and flow reserve (MFR) examination, especially useful in the diagnosis of multivessel coronary artery disease (CAD), can be assessed with a cadmium-zinc-telluride (CZT) SPECT gamma camera, as an alternative to the expensive and less available PET. However, study processing is not free from subjective factors. Therefore, this paper aims to evaluate intra- and interobserver repeatability of MBF and MFR values obtained by the same operator and two independent operators. Methods: This study included 57 adult patients. MBF and MFR were assessed using a Discovery NM530c camera in a two-day, rest/dipyridamople protocol, using 99mTc-MIBI. Data were processed using Corridor4DM software, twice by one operator and once by another operator. Results: The repeatability of the assessed values was quite good in the whole myocardium, LAD and LCX vascular territories, but was poor in the RCA territory. Conclusions: The poor repeatability of MBF and MFR in RCA vascular territory can be explained by poor automatic orientation of the heart axis during post-processing and a so-called “cardiac creep” phenomenon. Better automatic heart orientation and introduction of automatic motion correction is likely to drastically improve this repeatability. In the present state of the software, PET is better for patients requiring assessment of MFR in the RCA territory.

The Value of 99mTc-MIBI SPECT/CT in the Postoperative Assessment of Patients with Differentiated Thyroid Carcinoma

Background: The therapeutic approaches of differentiated thyroid carcinoma (DTC) are surgery, ablation therapy with the postoperative use of radioiodine-131 (131I), and thyroid-stimulating hormone (TSH) suppression therapy. After the surgical therapy, the patient should be assessed for remnants/metastases. Objective: The purpose of this research was to investigate the role of technetium-99m-methoxyisobutylisonitrile (99mTc-MIBI) single photon emission computed tomography/computed tomography (SPECT/CT) in the postoperative management of patients with DTC. Methods: The study comprised 22 DTC patients (13 women, 9 men; mean age 46.55 ± 13.27 y) who underwent a total thyroidectomy previously. All patients were investigated for thyroid remnants/metastases by 99mTc-MIBI SPECT/CT, posttherapy 131I whole-body scan (WBS) and ultrasound (US). Serum TSH, thyroglobulin and anti-Tg antibody levels were measured. Results of imaging modalities and laboratory measurements were compared with each other. Results: 99mTc-MIBI SPECT/CT, 131I WBS and US respectively demonstrated thyroid remnants in 15 (68.18%), 22 (100%) and 14 (63.63%) of the all patients and metastatic lymph nodes in 8 (100%), 6 (75%) and 6 (75%) of the 8 patients with lymph node metastases. 99mTc-MIBI SPECT/CT also demonstrated lung metastases in 2 patients (9.09% of all patients). The same result was obtained with 131I WBS. Conclusion : The findings of this study show that 99mTc-MIBI SPECT/CT can be effective for detecting metastases in patients with DTC who underwent surgery prior to 131I therapy.

Mask-Related Motion Artifact on 99mTc-MIBI SPECT: Unexpected Pitfalls of SARS-CoV-2 Countermeasures

A 61-year-old man was referred for myocardial perfusion scintigraphy (MPS) by an occupational physician to exclude coronary artery disease (CAD). The patient had a complete left bundle branch block (LBBB) that rendered the routine exercise stress test non-diagnostic, but otherwise had no history of heart diseases, good stress tolerance with no symptoms of angina, and no abnormalities in transthoracic echocardiogram, apart from contraction patterns typical for LBBB. Initial MPS, performed using technetium-labeled Sestamibi on a Discovery NM 530c camera equipped with solid-state semiconductor detectors, revealed a significant stress-induced ischemia that did not match the good overall condition of the patient. A motion detection procedure revealed significant heart motion in Z-axis during the stress study. Upon inquiry, the patient reported breathing difficulties caused by the mandatory mask, which slipped into an uncomfortable position during the study. Repeated acquisition, without motion artifacts, revealed no features of ischemia.

Molecular Imaging with 18F-FDG PET/CT and 99mTc-MIBI SPECT/CT in Osteitis Fibrosa Cystica Generalisata

Benign so-called “brown tumors” secondary to hyperparathyroidism are a rare diagnostic pitfall due to their impressively malignant-like character in various imaging modalities. We present the case of a 65-year-old male patient with multiple unclear osteolytic lesions on prior imaging suspicious for metastatic malignant disease. Eventually, findings of 18F-FDG PET/CT staging and 99mTc-MIBI scintigraphy resulted in revision of the initially suspected malignant diagnosis. This case illustrates how molecular imaging findings non-invasively corroborate the correct diagnosis of osteitis fibrosa cystica generalisata with the formation of multiple benign brown tumors.