Echocardiographic contrast perfusion imaging aids in the differentiation of cardiac masses. Compared with the adjacent myocardium, malignant and vascular tumors hyper-enhanced, whereas stromal tumors and thrombi hypo-enhanced.

The purpose of this investigation was to compare the efficiency of two different imaging protocols using two different clinically available 99mTc labelled myocardial perfusion tracers. One thousand one hundred and thirty-four imaging studies were performed prospectively, using either 99mTc-tetrofosmin or 99mTc-sestamibi, alternating the use of each tracer for a total period of 8 months. 99mTc-tetrofosmin rest studies were performed with injections of 259MBq-370MBq and imaging 30 min later. Exercise studies were performed with injections of 777MBq-1.11GBq and imaging 20 min later. 99mTc-sestamibi studies used doses similar to those in the 99mTc-tetrofosmin studies. Imaging followed a standard procedure, at 60 min after rest injection, and 30 min after exercise. For patients undergoing pharmacological stress testing99mTc-sestamibi was imaged 45 min after injection and 99mTc-tetrofosmin was imaged 30 min after injection. Variables analysed were (1) injection-to-imaging time for the procedure, and (2) the number of repeated scans because of extra cardiac activity. The completion time for the rest study was significantly shorter for 99mTc-tetrofosmin compared to 99mTc-sestamibi (47.7+/-21.7 min vs 74.3+/-25.8 min P<0.0001). Likewise, the total study time was shorter for 99mTc-tetrofosmin compared to 99mTc-sestamibi (90+/-32.7 min vs 124+/-37 min, P<0.0001). More importantly, the number of repeated scans was higher with 99mTc-sestamibi compared to 99mTc-tetrofosmin, 21.4% vs 10%, P=0.001 for rest studies and 16.4% vs 7.9% P=0.001 [corrected] for rest and stress. It was concluded that, using a same day rest/stress protocol, 99mTc-tetrofosmin provided higher patient throughput with fewer repeat scans. These factors may be considered for efficiency improvement in nuclear cardiology laboratories using 99mTc perfusion tracers.

A 64-year-old male presented with dyspnea and new-onset atrial fibrillation. His past medical history was remarkable for a fifty packyear history of smoking, asbestos exposure in his youth, and a family history of two uncles diagnosed with mesothelioma. The patient required oxygen of 6L nasal cannula to sustain a saturation of 92% and maintained a heart rate of 100 beats/min on a diltiazem drip. A chest CT showed tumor contiguous with the pericardium (Fig. 1A). Pleural biopsy was performed and pathology showed epitheliod type malignant mesothelioma (Fig. 1B). Transthoracic two-dimensional echocardiography demonstrated a large pericardial effusion (asterisks) with significant pericardial wall thickening (arrows), indicative of tumor extension from the pleura into the pericardium (Fig. 1C, D). Due to worsening dyspnea and the large pericardial effusion, the patient underwent pericardiocentesis with removal of 1000 cc of serosanguinous fluid. The patient's clinical status, however, continued to deteriorate, and the goals of care were altered to comfort care.Although unique cardiac findings have been reported in conjunction with malignant pleural mesothelioma, pericardial involvement occurs frequently. 1,2 It has been noted that approximately 50% of patients with malignant pleural mesothelioma have pericardial involvement based on the echocardiographic findings of pericardial effusion, thickening, calcification, or constriction physiology. 3 Autopsy studies have shown an even greater percentage of cardiac involvement in patients with malignant pleural mesothelioma. 2 Although symptoms of chest pain, dyspnea, and fatigue are generally attributed to pleural disease, echocardiography has been shown to assist in differentiating cardiac manifestations from progressive pulmonary involvement. 2 This case illustrates the echocardiographic findings of pericardial involvement by malignant pleural mesothelioma. Figure 1. (A) Infused chest CT scan depicting abutment of the right-sided pleural mesothelioma with the pericardium. (B) Pleural biopsy demonstrating infiltrative epitheliod type malignant mesothelioma cells. (C) and (D) Short-axis and apical four chamber views demonstrating a large pericardial effusion (asterisk marks) and significant pericardial wall thickening (arrow).

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