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Advantages of cardiac SPECT imaging over other cardiovascular imaging modalities cardiovascular magnetic resonance, contrast echocardiography and computed tomography include an extensive literature supporting efficacy and prognostic value, standardized protocols for performing studies, published user guidelines and appropriated criteria, as well as a proven cost effectiveness for diagnosis, management and risk assessment.
Thus, rather than being competitive, MSCT and SPECT imaging should be considered to be complementary for both diagnostic and a prognostic perspective, 9 as it has been shown in this case. The use of the latest generation of multidetector CT scanners and developing novel imaging protocols, combined SPECT and MSCT cardiac imaging, will play a prominent role to detect, quantify, and characterize both clinical and subclinical atherosclerosis, with potential reduction of radiation burden.
Corresponding author: Enrique Vallejo. Camino a Santa Teresa C No. Phone and Fax number: E mail: vallejo. Insuficiencia Cardiaca. Exportar referencia.
Usefulness of integrated dual-source multislice computed tomography and cardiac SPECT in a patient with previous myocardial infarction. Descargar PDF. We present the case of a year-old woman with chest pain and a history of an inferior myocardial infarction for which she underwent stenting in the right coronary artery. Patient was evaluated by cardiac SPECT and the recently introduced dual-source computed tomography DSCT system equipped with two X-ray tubes and two corresponding detectors , in order to detect ischemia associated to stent restenosis.
In this case, DSCT demonstrated a very high diagnostic performance to exclude in-stent restenosis, using a dual-energy protocol, and clearly showed subendocardial distribution of the myocardial perfusion defect, in contrast with the transmural defect seen in the SPECT images. As a result, the integration of a dual-energy CT protocol for the evaluation of myocardial blood pool during the assessment of coronary anatomy in this patient, may redefine the diagnostic power of DSCT..
Palabras clave:. Texto completo. Dual-energy CT of the heart for diagnosing coronary artery stenosis and myocardial ischemia-initial experience.. Dual-source cardiac computed tomography image quality and dose considerations.. Diagnostic accuracy of dual-source multi-slice CT-coronary angiography in patients with an intermediate pretest likelihood for coronary artery disease..
Usefulness of noninvasive cardiac imaging using dual-source computed tomography in an unselected population with high prevalence of coronary artery disease.. J, et al.. Left ventricular function and myocardial perfusion reserve in patients with ischemic heart disease.. Limitations of computed tomography coronary angiography J Am Coll Cardiol Cardiac myocar-dial perfusion imaging using dual source computed tomography.
Int J Cardiovasc Imaging in press.. Confocal images were reconstructed from 64 optical sections. During spontaneous activity of the hearts of sham-operated adult A. Traces of contractile activity of injured hearts are shown in Figures 1b-1d. Figure 1. Representative traces of spontaneously developed contractile activity of the whole heart of adult Ambystoma mexicanum , in isolated organ assays.
Traces correspond to control a and to day one b , five c , and 30 and 90 d after partial ventricular resection. Hearts were maintained in amphibian Ringer, pH 7. Upper panel shows a complete cycle of contractile activity and criteria of measurement of the ventricular and atrium tensions.
Figure 2. Effect of partial ventricular resection in adult Ambystoma mexicanum on ventricle and atrium tension A and heart rate B on day one 1d after partial ventricular resection as compared to control. Figure 3. Recovery of tension A and heart rate B values after partial resection of the ventricle of adult Ambystoma mexicanum as compared to control.
Both tension and heart rate were lower on days one and five after injury. The values returned gradually to those observed in control hearts and were similar to control at 30 and 90 days post-injury. Concomitant with the heart contractile activity we corroborated a gradual tissue restoration Figure 4. One day after damage, the ventricle showed an evident gap that was covered with a cloth Figure 4J ; after 30 days the hole was partially occupied by compact tissue Figures 4C, 4G, 4K , and 90 days after injury the heart showed a ventricular wall surface and myocardic tissue similar to control Figures 4D, 4H, 4L.
Figure 4. Images A-D are photographs of the heart observed on dissection microscopy and images E-L correspond to longitudinal heart sections stained with Masson's trichrome. One day after damage, the ventricle showed an evident gap F that was covered with a cloth J ; which is not evident in F because it was removed to photograph; 30 days after injury G, K the hole was partially occupied by compact tissue, and 90 days H, L after injury the heart showed a ventricular wall surface and myocardial tissue similar to control.
The arrows indicate the zone of resected tissue one day after injury F, cloth eliminated; J without elimination of cloth one days after injury, and recovery tissue at day 30 G and K and day 90 H and L after damage. In all cases, cell BrdU-labelled nuclei were surrounded by myocardial cytoplasm, as shown in the image reconstructed from 64 optical sections using confocal microscopy Figure 6. Figure 5. Panel I corresponds to representative images at day 5 after ventricular resection for a-sarcomeric actin-positive staining A and B , BrdU-positive nuclei in the same fields B and E and merged C, F.
Figure 6. Three-dimensional reconstruction of confocal analysis for a-sarcomeric actin TRITC; red and 5-bromo-2'-deoxyuridine BrdU FITC; green immunohistochemistry in ventricular myocardium of Ambystoma mexicanum on day five after surgical injury.
The image was reconstructed from 64 optical sections by confocal microscopy. In sections from sham-operated animals, cardiomyocytes with BrdU-labelled nuclei were not found. In all the cases, nuclei are surrounded by myocardial cytoplasm. Our results represent the first data concerning about the simultaneous evaluation of the structure and function of the heart of adult A. We have obtained evidence showing that the structural recovery of myocardium after ventricular injury in the heart of adult axolotl is accompanied by the restoration of its functional capacity.
This finding is in agreement with the proposal that adult organisms of early terrestrial animal species are endowed with a higher capacity of tissue regeneration. Functional assays of the heart of adult A.
Besides, the capability to develop tension of both ventricle and atrium was significantly decreased Figures 2 and 3. The force-frequency relationship is an important intrinsic regulatory mechanism of cardiac contractility in which an increase in contractile force is associated with an increase in amplitude, 21 however in failing ventricular myocardium this relation is lost. We suggest that the differences in the proportional changes between tension and HR in our study could be a compensatory response in proportion to the tissue and the force-frequency relationship recovery.
This might be related to the hypoxic bradycardia, which occurs in lower vertebrates and which could provide a number of direct benefits to the heart when oxygen supply in the spongy myocardium is precarious. Considering that the function of this structure in vertebrates is to develop the necessary pressure to pump blood to other organs, 1,4 its alterations would induce more evident adverse effects.
Additionally even when the injury was made in the ventricle, a smaller decrease in the capability of the atrium to develop tension was also observed Figure 3A , suggesting that the function of other cardiac structures was also altered on the first day as a consequence of the ventricular damage.
The progressive reestablishment of the heart rate along with the ventricular- and atrium-tension observed between 30 and 90 days after the PVA, shows that the heart of adult A. Furthermore, as proved later on, this functional restoration is also accompanied by the structural recovery of the heart, which is in accordance with the functional restoration in heart of A.
Structural evaluation, based on Masson's trichrome results Figure 4 together with the colocalization of BrdU-labelled nuclei and a-sarcomeric actin, with the surrounding of the BrdU-labelled nuclei by myocar-dial cytoplasm in the heart of A. These results are in accordance with the finding of a subset of cardiomyocytes that progress through mitosis and may enter to successive divisions in the newt, other adult urodele amphibian 15 and with previous reports that detect BrdU 11 and PCNA 12 in cardiomyocyte of A.
Our finding suggests that cardiomyocyte proliferation could be responsible of the structural recovery detected. However, other mechanisms proposed for tissue regeneration, such as the reprogramming of stem cell 23,24 or differentiated cells,25 cannot be ruled out. On the other hand, the reason behind the high regenerative capacity of the heart of adult A. The heart of adult amphibians consists of spongy, loose and trabecu-late myocardium, 26,27 similar to embryonic myocardium of other vertebrates 28, These characteristics allow the muscle to acquire oxygen by diffusion from luminal blood within the trabecular spaces, 30 which would facilitate the supplement of nutrients and growth factors to cardiac cells, which in turn may result in the production of new cardiomyocyte.
However, this remains to be analyzed in future studies. Finally, it is relevant to mention that in our study we demonstrated that the heart of A. We obtained the first quantitative evidence about the recovery of heart contractile activity after PVA in an adult urodele amphibian which indicates that the heart of A. The evaluation of the post-injury changes in the structure and function in the heart of non-mammalian vertebrates, like urodele amphibians, can be very useful, because the proportion of proliferating myocardial cells after damage is very high when compared to mammalian cardiomyocyte, which show a very low ability to proliferate.
Phone: 52 , ext. E-mail : cmamx yahoo. Insuficiencia Cardiaca. Exportar referencia. Functional and structural regeneration in the axolotl heart Ambystoma mexicanum after partial ventricular amputation.
Descargar PDF. In the present study we evaluated the effect of partial ventricular amputation PVA in the heart of the adult urodele amphibian Ambystoma mexicanum in vivo on spontaneous heart contractile activity recorded in vitro in association to the structural recovery at one, five, 30 and 90 days after injury.
Associated to contractile activity recovery we corroborated a gradual tissue restoration by cardiomyocyte proliferation. Our results represent the first quantitative evidence about the recovery of heart contractile activity after PVA in an adult urodele amphibian, indicating that the heart of A. These properties make the heart of A. Palabras clave:. Texto completo. Introduction The amphibian heart is characterized by a single ventricular chamber, an atrium partially separated by a perforated septum 1 and the absence of coronary circulation.
Methods Animals Neotenic adult specimens of A. Surgical heart injury Animals were anaesthetized by placing them in a MS water solution, w:v ICN Biomedicals and transferred to an ice plate to reduce their metabolic rate. Functional assay Six experimental and 4 sham-operated animals were sacrificed at each specific time 1, 5, 30 and 90 days after surgery.
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