جستجوی مقالات مرتبط با کلیدواژه « MIBI » در نشریات گروه « پزشکی »

Gated myocardial perfusion SPECT (GMPS) using [99mTc]Tc-MIBI allows the cardiac function assessment in addition to the myocardial perfusion. Although the prone position has been suggested as a complementary protocol in GMPS, there is no firm recommendation on its effect on function and physiologic conditions of cardiac. We aimed to evaluate the impact of supine and prone positions on left ventricular end-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (LVEF), and heart rate (HR). Ninety-six patients with no history of ischemic heart disease or cardiomyopathy participated in this study. Using GMPS at both supine and prone positions, volume-based cardiac function was evaluated. ESV, EDV, LVEF, and HR were obtained and compared between supine and prone positions. A two-tailed p-value of < 0.05 was considered significant. Using GMPS, no significant difference in ESV, EDV, LVEF, and HR was demonstrated between the two positions (p-value>0.05). The mean LVEF results derived from the supine versus prone position were 67.22% (42–93%) vs. 64.22% (41–89%) (p-value=0.71). ESV results were 23.28 vs. 27.23 (p-value=0.39). EDV results were 65.78 vs. 70.33 (p-value=0.27). Furthermore, HR results were close to each other in supine 72.22 (45-106) and prone 74.99 (47-110) positions (p-value=0.68). It seems that prone positioning causes no considerable change in cardiac volumes. As a result, the prone position can be an acceptable alternative to the supine position when volume-based assessments are considered.

Primary hyperparathyroidism (pHPT) is defined by the excess level of parathyroid hormone (PTH). Parathyroid adenoma is responsible for about 80% of all pHPT. Parathyroid adenoma with cystic feature and atypical pathology is recognized as a rare entity. Technetium-99m methoxy isobutyl isonitrile ([99mTc]Tc-MIBI) scintigraphy has favorable detection rate for ectopic gland as well as the brown tumors. SPECT/CT plays critical role in localizing abnormal tracer uptake. Herein, we report a severely hypercalcemic patient with cystic atypical parathyroid adenoma and mediastinal uptake, which was confined to a sternal lytic lesion (suggestive of brown tumor), which highlights the importance of SPECT/CT in [99mTc]Tc-MIBI imaging.

A 17-year-old boy with hyperparathyroidism exhibited a large cyst in the left hemi-thorax on his chest X-ray. The cyst was identified as a hydatid cyst. He was referred for biphasic methoxy isobutyl isonitrile (MIBI) parathyroid scan. A discrete ectopic parathyroid was detected in the left upper mediastinum in addition to accumulation of the MIBI tracer in the cyst wall. Using radio-guided occult lesion localization with an injection of 3 mCi 99m Tc - MIBI in the morning of the operation day, an ectopic adenoma was detected with a gamma probe within the thymus, resected with a consequent decline of serum high parathyroid hormone (PTH). This report is remarkable in two different aspects: the importance of radio-guided localization of ectopic adenoma, which in this case was within the thymus, and the accumulation of MIBI in hydatid cyst wall, as a unique report of this condition.

Peripheral Vascular Disease (PVD) is a major cause of morbidity and is associated with Coronary Artery Disease (CAD). We aimed to perform Lower Limb Perfusion Scan (LLPS) in patients referred for Myocardial Perfusion Imaging (MPI) and estimate prevalence of PVD in subgroups with normal and abnormal MPI results. We also compared quantitative indices of LLPS in patients with and without abnormal MPI results with semi-quantitative QPS indices.
120 patients referred for MPI entered the study. Exercise or dipyridamole infusion was used as stress modality. After 99mTc-MIBI injection at peak stress, whole body posterior views and planar images from thighs and calves were obtained. Gated MPI was done subsequently. Rest phase was performed the following day. LLPS was analyzed visually and quantitatively.
In patients with abnormal and normal MPI results, LLPS revealed 22.58% and 1.92% prevalence of PVD in exercise subgroup (P-Value=0.004) and 50.00% and 10.52% in dipyridamole subgroup (P-Value= 0.013), respectively. Both of these different prevalence were statistically significant. In exercise subgroup, mean ranks of Stress Index (Is) for all lower limb regions were statistically significantly greater in patients with normal MPI result. Also, among patients who had ischemia in exercise-rest MPI, negative correlations were seen between Is and Rest Index (Ir) of all regions and QPS quantitative indices.
LLPS with 99mTc-MIBI, combined with MPI is a feasible method to detect lower limbs ischemia, especially in patients with abnormal MPI results. Correlating quantitative indices of LLPS with MPI-QPS also reflect coexistence of CAD and PVD.

Osteitis fibrosa cystica is the classic patognomonic form of skeletal disease in hyperparathyroidism that characterizes with decreased cortical bone thickness compared to increased cancellous bone. We present a case of 52-year old female patient with osteolysis of the left calf on radiographic images. The bone scan detected multiple focal pathological accumulations in the skull, left tibia, both femurs and in the left ischium. The scan was indicative of secondary multiple skeletal metastases. Because the patient had no previous history of primary malignant disease, metabolic bone disease was suspected and also confirmed after i.v application of 99mTc-MIBI. The scan was in favor of parathyroid adenoma with bone complication (osteitis fibrosa cystica). Neck ultrasonography revealed hypoechoic oval mass below the left lower thyroid lobe that suggested the possibility of parathyroid adenoma. An increased ionized calcium level and PTH confirmed the diagnosis of primary hyperparathyroidism. Parathyroidectomy with radioguided surgery was performed. Hyperparathyroidism is a curable disease and a clinician should always bear in mind a metabolic bone disease when performing a nuclear bone scan where multiple bone lesions are detected (a hallmark of metastatic disease).

Multidrug resistance (MDR), which may be due to the over expression of P-glycoprotein (Pgp) and/or MRP, is a major problem in neoadjuvant chemotherapy of osteosarcoma. The aim of this study was to investigate the role of Tc-99m MIBI scan for predicting the response to pre-operative chemotherapy. Twenty-five patients (12 males and 13 females, aged between 8 and 52y) with osteosarcoma were studied. Before the chemotherapy, planar 99mTc-MIBI anterior and posterior images were obtained 10-min [tumor-to-background ratio: (T1/B1)10min] and 3-hr after tracer injection. After completion of chemotherapy, again 99mTc-MIBI scan was performed at 10-min after tracer injection. In addition to calculation of decay corrected tumor to background (T/B) ratios, using the 10-min and 3-hr images of the pre-chemotherapy scintigraphy, percent wash-out rate (WR%) of 99mTc-MIBI was calculated. Using the 10-min images of the pre- and post-chemotherapy scans, the percent reduction in uptake at the tumor site after treatment (Red%) was also calculated. Then after surgical resection, tumor response was assessed by percentage of necrosis. All patients showed significant 99mTc-MIBI uptake in early images. Only 9 patients showed good response to chemotherapy (necrosis≥90%) while 16 patients were considered as non-responder (necrosis<90%). There was no statistical significant difference between non-responders and responders in (T1/B1)10min.There was a significant negative correlation between WR% and percentage of necrosis (P=0.001). On the other hand, there was a significant correlation between Red% and percentage of necrosis (P<0.001).There was also statistical significant difference in WR% and Red% between non-responders and responders (both P< 0.001). Washout rate of 99mTc-MIBI in pre-chemotherapy scintigraphy as well as Red% using pre- and post-chemotherapy MIBI scintigraphy are useful methods for predicting response to neoadjuvant chemotherapy.

Mitochondria play an important role in energy production for the cell. The proper function of a myocardial cell largely depends on the functional capacity of the mitochondria. Therefore it is necessary to establish a novel and reliable method for a non-invasive assessment of mitochondrial function and metabolism in humans. Although originally designed for evaluating myocardial perfusion, 99mTc-MIBI can be also used to evaluate cardiac mitochondrial function. In a clinical study on ischemic heart disease, reverse redistribution of 99mTc-MIBI was evident after direct percutaneous transluminal coronary angioplasty. The presence of increased washout of 99mTc-MIBI was associated with the infarct-related artery and preserved left ventricular function. In non-ischemic cardiomyopathy, an increased washout rate of 99mTc-MIBI, which correlated inversely with left ventricular ejection fraction, was observed in patients with congestive heart failure. Increased 99mTc-MIBI washout was also observed in mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and in doxorubicin-induced cardiomyopathy. Noninvasive assessment of cardiac mitochondrial function could be greatly beneficial in monitoring possible cardiotoxic drug use and in the evaluation of cardiac damage in clinical medicine.

Parathyroid adenoma involving a single parathyroid gland is the underlying cause of 80-85% of primary hyperparathyroidism (PHPT). Skeletal system is significantly affected by PHPT. Brown tumors are known to have affinity for 99mTc-MIBI. We report a rare case of PHPT presenting with diffuse bony pain, high calcium level and significantly elevated alkaline phosphatase level. 99mTc-pertechnetate/99mTc-MIBI subtraction, performed as a part of routine protocol, showed several brown tumors showing affinity for both 99mTc-pertechnetate and 99mTc-MIBI. They were further characterized using hybrid SPECT/CT. To the best of our knowledge, 99mTc-pertechnetate affinity in brown tumors has not been previously described.