Simultaneous Development of ST-Segment Elevation Myocardial Infarction and Pulmonary Embolism in an Healthy Elderly Woman

A 73-year-old woman who presented with chest discomfort visited the emergency room. The 12-lead electrocardiography showed ST-segment elevation in II, III, and lead augmented vector foot. Emergent coronary angiography revealed a thrombus in the distal right coronary artery. Percutaneous coronary angioplasty with a stent was performed. After the procedure, persistent dyspnea occurred. Her chest computed tomography (CT) showed occlusion of the bilateral pulmonary artery. We could not find a source for the embolization or a hypercoagulable state. We started a course of dual antiplatelets with oral anticoagulants. Pulmonary embolism was resolved at follow-up chest CT scan. Aspirin, clopidogrel and warfarin were given for 6 months. The patient is doing well now 1 year after the episode.

Acute Pulmonary Oxygen Toxicity in Rats: Findings and Lung Density Changes in High Resolution Computed Tomography

PURPOSE: To evaluate imaging findings and lung density changes after 95% oxygen inhalation in rat. MATERIALS AND METHODS: A total of 18 rats were divided into three groups on the basis of inhalation time: group I(n=6) inhaled 95 % oxygen for 24 hours, and group II(n=6) for 48 hours, group III(n=6) for 60 hours. A control group(n=6) inhaled room air(21% oxygen). Chest radiograph and high resolution computed tomography were performed, and pathologic and imaging findings were compared. RESULTS: Chest radiograph showed abnormality only in group III. High resolution CT, however, revealed abnormal findings in all three groups : diffuse ground glass opacity in groups I, II and III, additional focal patchy consolidation at the peripheral portion in group II, and diffuse consolidation in group III. Lung density was sig-nificantly higher in group I than in controls(p 0.05). In group III, density was significantly higher than in group II. The lung density changes seen in all groups showed a bilateral diffuse increased pattern. but, in group III, changes were more severe in the central, peripheral and posterior portion of the lower lung. Ground glass opacity and focal patchy consolidaton seen on HRCT were found on pathologic examination to be due to alveolar cell hyperplasia and septal thickening. Consolidation was caused by alveolar edema and hemorrage. Pathologic lesions were randomly distributed in both lungs. CONCLUSION: One HRCT images, rat exposed to hyperoxia showed ground glass opacity, patchy consolidation and diffuse consolidation. Depending on exposure time, the pathologic findings also indicated increased lung density and a bilateral, diffuse distribution pattern, as well as alveolar cell hyperplasia and septal thickening, alveolar edema and hemorrage. HRCT may be more helpful than simple X-rays for the early detection of pulmonary oxygen toxicity.

Myocardial Assessment during Subacute Stage after Ischemia-Reperfusion: Gd-DTPA-polylysine Enhanced MR Imagingin Cats

PURPOSE: To investigate changes in the size and degree of signal enhancement of reperfused myocardium during the subacute stage of an ischemic episode, using Gd-DTPA-polylysine enhanced magnetic resonance imaging. MATERIALS AND METHODS: In six cats, the left anterior descending artery was occluded for 150 minutes, and this was followed by reperfusion. Contrast enhanced T1-weighted spin echo magnetic resonance imaging using gadolinium diethylene triamine penta acetic acid-polylysine (Gd-DTPA-polylysine) was performed on the 1st , 2nd, and 6th days of the reperfusion period. The size of ischemic myocardium was estimated each day on MR images by measuring the size of signal enhanced area and the degree of signal enhancement according to time was measured. After sacrificing the animals on day 6, the myocardial specimen was histochemically stained with 2,3,5-triphenyltetrazoliumchloride(TTC). RESULTS: Signal enhancement and the size of the ischemic myocardium, as seen on MR images,decreased linearly during the six days of the subacute stage. On the 6th day, however, signal intensity was still higher than that of normal myocardium, and the size of signal enhanced area measured on MR images was significantly larger than on TTC-stained specimens (p<0.001). CONCLUSION: We conclude that the size of enhanced area and degree of signal enhancement decreased linearly during the subacute stage of reperfused myocardialinfarction and that the area of MR signal enhancement during the acute stage includes both irreversibly andreversibly damaged myocardium.

Changes of Brain Energy Metabolism in Cats during Hypoxemia followed by Reoxygenation with Room Air or 100% Oxygen: in vivo 31P Magnetic Resonance Spectroscopic Study / 대한마취과학회지

BACKGROUND: This study was purposed to study the effect of reoxygenation with room air as compared to FiO2 1.0 in a feline model subjected to hypoxemia followed by reoxygenation. Changes in the brain energy metabolism were investigated by 31P magnetic resonance spectroscopy(31P MRS). METHODS: Twelve cats were employed for this study and divided into two groups(6 cats each). Both groups were subjected to hypoxemia for 1 hr with FiO2 0.07 followed by reoxygenation for 2hrs. For group I, the reoxygenation was done by FiO2 1.0 and for group 2, by room air. Brain intracellular pH and the ratio of Pcr/Pi(phosphocreatine/inorganic phosphate) were calculated from the spectra acquired every 15 mimutes of the hypoxemia and reoxygenation periods. RESULTS: The intracellular pH of the baseline were 7.07+/-0.01 and 7.04+/-0.01 for group 1 and group 2, respectively, and dropped to 6.89+/-0.04 and 6.83+/-0.06 during hypoxemia. For both groups, the intracellular pH returned to baseline values after 30 minutes of reoxygenation. The ratios of Pcr/Pi of the baseline were 2.41+/-0.21 and 2.47+/-0.15, for group 1 and group 2, and dropped to 0.77+/-0.10 and 0.70+/-0.11, respectively, during hypoxemia and recovered to the baseline values after 30 minutes of reoxygenation for both groups. For both pH and the ratios of Pcr/Pi, the differences between the groups were statistically insignificant. CONCLUSION: From this study, we can conclude that reoxygenation by room air is as effective as FiO2 1.0 in the feline model of hypoxemia investigated by 31P MRS.

A Study Using Diffusion-Weighted MR Image in the Experimental Models with Diffusion Difference

PURPOSE: To see the stability and error in the diffusion-weighted magnetic resonance (MR) imaging technique in the experimental models and to observe the signal intensities in the early cerebral lesions of the animal models. MATERIALS AND METHODS: Diffusion coefficients of acetone and distilled water were measured by diffusion-weighted MR image and were compared with actual values. Differentiation of diffusion from perfusion were done at the resin flow phantom. The signal intensities caused by early parenchymal changes were measured in normal, hypovolemic, and embolic, and dead animal models by using diffusion-weighted image and compared with pathoIogic finding and vital staining. RESULTS: Diffusion coefficients of acetone and distilled water were 4.48 x 10-3 and 2.72 x 10-3 which were very close to the actual values. Diffusion-weighted MR image obtained at flow phantom was not affected by flow (perfusion) at the 100-400 of b-factor range. Animal study done at that b-factor range revealed a significant signal difference between the left and right sides only at the embolic model induced by polyvinyl alchol particles (p<0.05). These changes were not detected in microscopic finding but could be identified in vital staining. CONCLUSION: Diffusion-weighted MR image can be used to detect early parenchymal change when the appropriate b-factor range was applied.

Myocardial Protection of Lidocaine in Acute Ischemia-Reperfusion : A 31P MR Spectroscopic Study in Cats

BACKGROUND: Lidocaine is a well known antiarrhythmic agent. However, recent reports indicate that indocaine has myocardial protective effects on acute myocardial ischemia and reperfusion. The exact mechanism of myocardial protection of lidocaine is still not clearly understood. In this study we intended to assess the effects of lidocaine on high energy phosphate metabolism in cats subjected to myocardial ischemia-reperfusion by using 31P MR spectroscopy. Effect of lidocaine on size of infarct will also be evaluated by 2, 3, 5-triphenyltetrazolium chloride(TTC) staining. METHODS: Twenty-seven cats were used for this study. The animals were divided into three groups : for group 1(n=10) and group 2(n=7), animals were subjected to a 90 min of LAD occlusion followed by a 90 min of reperfusion ; for group 3(n=10), a 20 min of occlusion followed by a 90 min of reperfusion. In group 2 and group 3, lidocaine(5mg/kg/hr) was infused continuously during the occlusion and reperfusion periods with an initial bolus injection(1mg/kg) before ligation of LAD. In-vivo MR spectroscopy was performed on a 4.7T Biospec System(Bruker, Switzerland). A home-made surface coil(diameter : 1.5cm) was used to receive31p signals from the myocardium underwent ischemic and reperfusion damage. RESULTS: Decrease of PCr during ischemic period was not different between each groups : PCr showed less than 30% of the baseline value at L-30 in group 1 and group 2 and at L-20 in group 3. More than 90% recovery of PCr was achieved at R-30 in group 2 and group 3, whereas less than 50% of PCr was recovered in group 1. Decrease of ATP during ischemic period was less pronounced in group 2 than in group 1 : in group 2 ATP depleted down to 25% of the baseline at L-90, whereas in group 1 ATP decreased to 50% of the baseline. Recovery of ATP during reperfusion period was not signiflcant in all three groups. On TTC staining, evidence of infarct was seen in all cases of group 1 : the area of infarct was 12.3+/-2.7% of the left ventricular mass and 23.9+/-6.1% of the area at risk. On the contrary, there was no evidence of infact in any case of group 2 and group 3. CONCLUSION: In this study, we found that lidocaine has myocardial protecitve effects on ischemia-reperfusion in cats. Lidocaine improves high energy phosphorous metabolism during ischemia and reperfusion as well as reduces infarct size.

Comparison of Gadolinium Polylysine and Gadopentetate in Contrast Enhanced MR Imaging of IVlyocardial Ischemia-Reperfusion in Cats

PURPOSE: To assess the signal enhancement by gadolinium-DTPA-polylysine (Gd-polylysine) as compared to gadopentetate (Gd-DTPA) in MR imaging of heart that have undergone ischemia-reperfusion, and to estimate the extent of myocardial damage covered bythe MR signal enhancement. MATERIALS AND METHODS: A series of contrast enhanced cardiac MR images were obtained from 17 cats subjected to a 90 minutes of occlusion of the left anterior descending coronary artery (LAD) followed by a 90 minutes of raperfusion. Time courses of changes in the signal intensity (Sl) of the ischemic area were measu red in Gd-polylysine group (8 cats) and Gd- DTPA group (9 cats). The size of U R signal enhanced area was then compared to the sizes of infarction and the area at risk revealed byTTC histochemical staining. RESULTS: Maximum Sis were obtained at 60 minutes and 30 minutes after injection of the contrast material, respectively for Gd-polylysine group and Gd-DTPA group. Signal enhancement was stronger and persistent for a longer period in Gd-polylysine group than in GD-DTPA group. Sizes of the enhanced area, the infarction, and the area at risk were about 30%, 15%, and 50% of the total left ventricle (LV) area; the difference between the groups was statistically insignificant. CONCLUSION: Gd-polylysine can be used better for a blood pool marker than Gd-DTPA in MR imaging of myocardial ischemia, due to its strong and persistent signal enhancement. The MR signal enhanced area includes both the infarcted area and a portion of the area at risk.

Comparative of P spectroscopy and histochemical mapping in myocardial infarction in cats

This study was performed to assess the accuracy of 31P magnetic resonance spectroscopy(MRS) in the evaluation of myocardial ischemia in cats. Twelve cats underwent myocardial ischemia and reperfusion induced by 90 minutes ligation followed by 90 minutes recirculation of the left anterior descending coronary artery (LAD). MRS was performed using a 4.7T Biospec MRS/MRI system (Bruker, Switzerland). An inner diameter 1.5cm-sized doubly tuned surface coli was used for the collection of the MR signal. The coli was implanted to the epicardial surface at the expected area of infarction. 31P MRS was acquired before and during the periods of ischemia and reperfusion with 5-minute to 30-minute of intervals. After completion of the 31P MRS study, animals were sacrificed and the hearts were excised for 2,3,5-triphenyl tetrazolium chloride (TTG0 histochemical staining. The area of infarct was measured on the photographs of TTG stained heart slices using a computer programmed planimetry and the results were compared with those of the 31P MRS study. The level of phosphocreatine (PCr) was decreased to 28.2±6.9% of the baseline level 90 minutes after occlusion and recovered to 43.8±4.8% of the baseline level at the end of the reperfusion. A 50% depletion of PCr was reached 5 minutes after the LAD occlusion. The ATP was decreased to a 26.6±3.6% of the baseline level 90 minutes after occlusion and recovered to a 35.9±6.0 of the baseline level 90 minutes after reperfusion. The decreasing rate of ATP was slower than that of PCr showing a 50% of depletion 15 minutes after occlusion. The PCr/ATP ratio was 1.16±0.09 at the baseline, decreased to 0.88±0.07 at 30 minutes of occlusion, and then progressively increased during the late ischemic and reperfused periods. The ratio of the infarcted area to the effective signal area of the surface coli was inversely correlated to the ATP (r=0.68) and PCr (r=0.40) levels obtained at the end of reperfusion. In conclusion, 31P MRS reflects the changes in myocardial high energy phosphorous metabolism during the actue ischemia and reperfusion. If on adequate localization technique is feasible, 31P MRS can be used clinically in the diagnosis and monitoring of the patients with acute myocardial infarction.

P MR spectroscopy study of the brain at 4.7 T in new borns

In vivo 31P NMR spectra were obtained in eight infant brain at 4.7T. Each phosphorus metabolite and its ratio were analyzed to evaluate the brain damage and maturity, and compared with the reported data obtained at the lower field strength. Measurement of T1 relaxation time at 4.7T was done in an infant and a cat brain in vivo. PCr/Pi and PCr/β-ATP ratio were used as a marker of brain damage. PME/PDE revealed higher values than those of the reported data obtained at the lower field strength and the difference was partly attributed to the long T1 relaxation time of PME rather than the brain immaturity. Although the resolution of the spectrum was improved at 4.7T, a long repetition time is recommended to minimize T1difference of phosphorus metabolites of brain at 4.7T.

In vitro 31P NMR spectroscopic assessment of the endurance and recovery capacity of skeletal muscle: comparison between the sedentaries and canoe athletes

In vivo 31P NMR spectroscopic study of forearm wrist flexor muscles was performed in two groups of volunteers composed respectively of 6 sedentaries and 6 canoe athletes. A continuous isometric contraction of endurance exercises was adopted in oder to assess the endurance capacity and recovery potential of skeletal muscles. Differences in high energy phosphorus metabolism between the sedentaries and athletes were evaluated with and emphasis on the intracellular pH and Pi/PCr ratio as indicators of high energy phosphorus metabolism. There were no differences of baseline pH and Pi/PCr ratio between the two groups. The athletes sustained the exercise at more acidic intracellular pH and at a higher Pi/PCr ratio of intracellular conditions for an all-out than did the sedentaries. The recovery rate of pH showed no difference between the two groups. There was a tendency of faster recovery of Pi/PCr in athletes showing half recovery time(T1/2) of 39.0±3.0 seconds as compared to that of sedentaries (55.7±7.5 seconds). The recovery rate of Pi/PCr as a function of Pi/PCr ratio at a given period of time was significantly faster in athletes than in sedentaries (P<0.001). The correlation coefficient of the recovery rate of Pi/PCr against the Pi/PCr ratio was 0.985 and 0.914 respectively for the athletes and sedentaries. The pH and the Pi/PCR ratio at an all-out state can be used as indicators of endurance capacity and the recovery rate of Pi/PCr, as a reovery potential of skeletal muscles.

In vitro NMR spectroscopy of high-energy phosphorus metabolism in the forearm muscle comparison between elite athletes and sedentari- es

No abstract available.

Effects of 2-Deoxy-D-Glucose on Metabolic Status, Proliferative Capacity and Growth Rate of FSall Tumor: Observations made by In Vivo 31P-Nuclear Magnetic Resonance Spectroscopy and Flow Cytometry / 대한치료방사선과학회지

The effect of 2-deoxy-d-glucose (2-DDG) on C3H mouse fibrosarcoma (FSall) was studied. Metabolic status, especially for energy metabolism, was studied using in vivo 31P-MRS, proliferative capacity was observed on flow cytometry (FC) and growth rate was measured after transplantation of 106 viable tumor cells in the dorsum of foot of C3Hf/Sed mice. One gram of 2-DDG per kg of body weight was injected intraperitoneally on 12th day of implantation. Average tumor size on 12th day of implantation was 250mm3. Growth rate of FSall tumor was measured by tumor doubling time between tumor age 5-12 days was 0.84 days with slope 0.828 and tumor doubling time between tumor age 13-28 days was 3.2 days with slope 0.218 in control group. After 2-DDG injection, tumor doubling time was elongated to 5.1 days with slope 0.136. The effect of 2-DDG studied in vivo 31P-MRS suggested that the increase of phosphomonoester (PME) and inorganic phosphate (Pi) by increasing size of tumor, slowed down after 2-DDG injection. Flow cytometry showed significantly increased S-phase and G2+M phase fraction suggesting increased proliferative capacity of tumor cells in the presence of 2-DDG. Authors observed an interesting effect 2-DDG on FSall tumor and attempt to utilize as an adjunct for radiotherapy.