Integración de los parámetros de remodelado, sincronía y velocidad máxima de vaciado para evaluar la función sistólica del ventrículo izquierdo / Integration of ventricular remodeling, synchrony and filling rate parameters to improve the assessment of left ventricular systolic function

Objetivos El objetivo es estudiar la relación entre los parámetros estructurales, de remodelado, de sincronía y de función sistólica del ventrículo izquierdo (VI) mediante gSPECT. Obtener los valores de corte del VI para el índice de la forma telediastólica (iFTD), el índice de la forma telesistólica (iFTS), el índice de excentricidad (iEX) y la velocidad máxima de vaciado (VMV). Desarrollar un nuevo índice para evaluar diferentes patrones de función sistólica del VI. Material y métodos Analizamos prospectivamente 238 pacientes (edad: 63,4±13 años) estudiados mediante gSPECT de esfuerzo-reposo (grupo-control, n=148; pacientes con infarto de miocardio [IM] previo, n=90). Estudio aprobado por el Comité de Ética del Hospital (PR[AG]168.2010). Resultados En el grupo-control, el índice del volumen telediastólico (iVTD) y el iEX influyeron en el iFTD (r2: 0,52, p<0,001). El iVTD, la VMV, ser varones y el iEX (r2: 0,44; p<0,001) influyeron en el iFTS. El iFTD, iFTS, la fracción de eyección VI (FEVI) y el volumen de eyección sistólica (r2: 0,62; p<0,001) influyeron en el iEX. La FEVI, la frecuencia cardíaca, el ancho de banda (AB) y la desviación estándar influyeron (r2: 0,76; p<0,001) en la VMV. Los valores de corte para iFTD, iFTS, iEX y VMV fueron 0,59, 0,42, 0,87 y −3,3 respectivamente. La VMV, el iFTS y el AB fueron los parámetros mejor relacionados con los pacientes con IM previo (AUC: 0,89), y sumados a la FEVI permitieron obtener distintos patrones de función sistólica (índice PERRS). Conclusiones Los parámetros de remodelado, sincronía y función sistólica del VI deben interpretarse simultáneamente, ya que esto permite obtener distintos patrones de función sistólica del VI (AU)

Introduction and objectives The aim of this study is to assess the relationship between structural, remodeling, synchrony, and systolic left ventricular (LV) function parameters using gated-SPECT myocardial-perfusion-images (gSPECT-MPI). In addition, obtaining the cut-off values for end-diastolic LV-shape-index (EDLVsi), end-systolic LV-shape-index (ESLVsi), ECC (eccentricity-index) and PER, and developing a new index to evaluate different patterns of the LV systolic function. Methods The study was approved by the Hospital's Ethical-Committee (PR[AG]168.2010), and all patients gave their informed consent. We analyzed prospectively 238 patients (age 63.4±13 years) who underwent stress-rest gSPECT-MPI (control-group, n=148; patients with previous myocardial infarction [MI], n=90). Results In the control group, with regard to remodeling parameters: the end-diastolic-volume-index (EDV) and the ECC were the parameters that influenced the EDLVsi (r2: 0.52, P<.001). EDV, PER, men, and the ECC were the parameters (r2: 0.44; P<.001) which influenced the ESLVsi. EDLVsi, ESLVsi, LVEF and the stroke-volume were the parameters (r2: 0.62; P<.001) which influenced the ECC. With regards to PER: LVEF, heart-rate, bandwidth, and the standard-deviation were the influencing parameters (r2: 0.76; P<.001). The cut-off values for EDLVsi, ESLVsi, ECC, and PER were 0.59, 0.42, 0.87, and 3.3, respectively. The PER, the ESLVsi and the bandwidth were the parameters related to patients with previous MI (AUC: 0.89); and they allow the assessment of different patterns of systolic function (PERRS-index: Peak-Emptying-Rate, left ventricular-Remodeling and Synchrony). Conclusions The remodeling, synchrony and the systolic function parameters of the LV should be interpreted together (PERRS-index). In this way, we obtain different patterns of LV systolic function (AU)

Integration of ventricular remodeling, synchrony and filling rate parameters to improve the assessment of left ventricular systolic function.

INTRODUCTION AND OBJECTIVES: The aim of this study is to assess the relationship between structural, remodeling, synchrony, and systolic left ventricular (LV) function parameters using gated-SPECT myocardial-perfusion-images (gSPECT-MPI). In addition, obtaining the cut-off values for end-diastolic LV-shape-index (EDLVsi), end-systolic LV-shape-index (ESLVsi), ECC (eccentricity-index) and PER, and developing a new index to evaluate different patterns of the LV systolic function. METHODS: The study was approved by the Hospital's Ethical-Committee (PR[AG]168.2010), and all patients gave their informed consent. We analyzed prospectively 238 patients (age 63.4 ±â€¯13 years) who underwent stress-rest gSPECT-MPI (control-group, n = 148; patients with previous myocardial infarction [MI], n = 90). RESULTS: In the control group, with regard to remodeling parameters: the end-diastolic-volume-index (EDV) and the ECC were the parameters that influenced the EDLVsi (r2: 0.52, p < 0.001). EDV, PER, men, and the ECC were the parameters (r2: 0.44; p < 0.001) which influenced the ESLVsi. EDLVsi, ESLVsi, LVEF and the stroke-volume were the parameters (r2: 0.62; p < 0.001) which influenced the ECC. With regards to PER: LVEF, heart-rate, bandwidth, and the standard-deviation were the influencing parameters (r2: 0.76; p < 0.001). The cut-off values for EDLVsi, ESLVsi, ECC, and PER were 0.59, 0.42, 0.87, and 3.3, respectively. The PER, the ESLVsi and the bandwidth were the parameters related to patients with previous MI (AUC: 0.89); and they allow the assessment of different patterns of systolic function (PERRS-index: peak-emptying-rate, left ventricular-remodeling and synchrony). CONCLUSIONS: The remodeling, synchrony and the systolic function parameters of the LV should be interpreted together (PERRS-index). In this way, we obtain different patterns of LV systolic function.

Effect of cardiac resynchronization therapy on septal perfusion and septal thickening: Association with left ventricular function, reverse remodelling and dyssynchrony.

BACKGROUND: We evaluated the effect of cardiac resynchronization therapy (CRT) on septal perfusion and thickening at 6 months post implantation assessed on Tc99m-MIBI Gated myocardial perfusion SPECT (GMPS).We also studied the association of change in septal perfusion and thickening with primary outcome defined as at least one [improvement in ≥1NYHA class, left ventricular ejection fraction (LVEF) by ≥ 5%, reduction of end-systolic volume (ESV) by ≥ 15%, and improvement ≥ 5 points in Minnesota living with heart failure questionnaire (MLHFQ)]. METHOD: One hundred and five patients underwent clinical and GMPS evaluation before and at 6 months post CRT. RESULT: Post CRT there was significant improvement in mean normalized septal perfusion uptake and in septal thickening (P value = 0.001, both). There was no significant relation between improvement in septal perfusion and primary outcome. However, improvement in septal thickening was statistically significant with favorable primary outcome (P = 0.001).There was no significant correlation between improvement of septal perfusion and improvement in LVEF, reduction in End diastolic volume (EDV), ESV, and Left ventricular Dyssynchrony (LVD). But, there was significant correlation between improvement of septal thickening and these parameters. CONCLUSION: Improvement in septal thickening was associated with reverse remodeling, improvement in LVEF, and reduction of LVD.

Laparoscopic repair of congenital pleuroperitoneal hernia using a polypropylene mesh in a dog / Correção laparoscópica de hérnia pleuroperitoneal utilizando malha de polipropileno em cão

Pleuroperitoneal hernias are the most uncommon type of diaphragmatic hernias in dogs and cats. The treatment of choice is surgery and may involve the use of prosthetic implant through celiotomy. In the current report, laparoscopic repair of a congenital pleuroperitoneal hernia using polypropylene mesh in a dog is described. The surgery was feasible. Appropriate reduction of the hernia was carried out and no complications were noted.

Hérnias pleuroperitoneais são o tipo mais incomum de hérnias diafragmáticas em cães e gatos. O tratamento de escolha é cirúrgico e pode envolver o uso de implantes protéticos na abordagem via laparotomia. No presente relato, é descrito o reparo de uma hérnia pleuroperitoneal congênita através de laparoscopia com utilização de malha de polipropileno. A cirurgia foi viável. Houve redução apropriada da hérnia sem observação de complicações.

Expression of urokinase type plasminogen activator receptor (uPAR) in the bovine oviduct: Relationship with uPA effect on oviductal epithelial cells.

Urokinase type plasminogen activator (uPA) is an oviductal fluid component whose activity is regulated by binding to urokinase type plasminogen activator receptor (uPAR). In this study uPAR and uPA gene expression in bovine oviduct were evaluated and similar expression patterns for both uPAR and uPA mRNAs were observed during the estrous cycle. Immunolocalization of uPAR at the apical zone of epithelial cells suggests that uPA action would be focalized in the oviductal lumen, triggering intracellular signaling pathways. As uPAR expression was also observed in in vitro cultures of oviductal epithelial cells, the effect of uPA was explored using this culture model. Real-time RT-PCR demonstrated that c-fos expression in oviductal cell cultures increases under uPA stimulation. These results suggest that uPA/uPAR binding would be involved in signaling pathways that activate transcription factors and would regulate the synthesis of molecules concerned with the arrangement of a particular oviductal microenvironment.

Expression of DNA methyltransferase genes in four-cell bovine embryos cultured in the presence of oviductal fluid.

The possible epigenomic effect of oviductal fluid on expression of DNA methyltransferase (DNMT) genes was examined in early bovine embryos (4-cell stage). Real-time quantitative PCR was performed to determine the relative expression of DNMT1, DNMT3a and DNMT3b transcripts in embryos cultured in vitro in the presence or absence of oviductal fluid. Expression of DNMT1 significantly increased when cultured with oviductal fluid, whereas DNMT3a and DNMT3b transcripts were unaffected by the addition of oviductal fluid. These results may help reveal the role of oviductal factors in the regulation of DNMT expression.

Measuring left ventricular mechanical dyssynchrony from ECG-gated SPECT myocardial perfusion imaging.

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. The traditional criteria to select patients for CRT (New York Heart Association [NYHA] class III or IV, depressed left ventricular [LV] ejection fraction, and prolonged QRS duration) result in at least 30% of the selected patients with no response to CRT. Recent studies with echocardiography have shown that the presence of LV dyssynchrony is an important predictor for response to CRT. However, the recent report from the predictors of response to cardiac resynchronization therapy (PROSPECT) trial suggested that under ''real-world'' conditions the current available echocardiographic techniques including tissue Doppler imaging (TDI) and myocardial strain-rate imaging are not ready for routine clinical practice to assess LV dyssynchrony. Phase analysis is a recently developed technique that allows measuring LV dyssynchrony from electrocardiogram (ECG)-gated single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI). This technique uses Fourier harmonic functions to approximate regional wall thickening over the cardiac cycle and to calculate regional onset of mechanical contraction (OMC) phases. These OMC phases are obtained three-dimensionally over the entire left ventricle to quantitatively assess the degree of LV dyssynchrony. This technique has been compared to TDI and shown promising results in clinical validations. The advantages of this technique over echocardiography in measuring LV dyssynchrony are its automation, its high repeatability and reproducibility. It can be applied to any conventional GSPECT MPI study with no additional procedure. In this review the phase analysis methodology is described and its up-to-date clinical validations are summarized.

Gated stress-only 99mTc myocardial perfusion SPECT imaging accurately assesses coronary artery disease.

In today's cost containment environment it is important to consider changes to standard protocols which would reduce cost, particularly if there is no significant loss of diagnostic accuracy. The aim of the present study was to assess the usefulness of a gated stress-only Tc sestamibi protocol in comparison to conventional gated dual isotope rest-stress myocardial perfusion single photon emission computed tomography (SPECT) in the detection and localization of coronary artery disease (CAD). Sixty-five consecutive patients (65+/-10 years, 22 women) who had undergone conventional gated perfusion SPECT were chosen retrospectively. Fifty-three of these 65 patients had previous coronary arteriography, 45 with at least one stenosis, eight without stenosis, and 12 of these 65 patients had <5% likelihood of CAD. Three readers interpreted the gated stress-only and dual isotope studies in separate sessions blinded to (1). their previous readings, (2). the interpretation by others, and (3). the angiographic results. Readers used a five-point scale to score their visual and quantitative assessment of perfusion, function and compromised vascular territory. Their average score was used for determination of the accuracy by using receiver operating characteristic (ROC) analysis of the techniques. The areas under ROC curves were determined for the detection of CAD and localization of vascular territories. Fifty-four of these patients had 97 significant stress induced perfusion defects as determined by the CEqual quantitative program. The agreement between protocols for the assessment of reversibility in these 97 defects was analysed. There were no statistically significant differences between dual isotope rest/stress and gated stress-only studies for the detection and localization of CAD. The area under the dual isotope rest/stress ROC curve was 0.78+/-0.07 compared to the area under the gated stress-only ROC curve of 0.80+/-0.06, resulting in P=0.30. For the combined vessels comparison of the area under the dual isotope rest/stress ROC curve was 0.73+/-0.04 versus the area under the gated stress-only ROC curve of 0.74+/-0.04, resulting in P=0.27. Similar non-significant differences were obtained when comparing the area under the dual isotope versus gated stress-only ROC curves for the left anterior descending vascular territory (LAD, 0.61+/-0.08 vs 0.660.08, P=0.14), the left circumflex vascular territory (LCX, 0.82+/-0.07 vs 0.81+/-0.06, P =0.47) or the right coronary vascular territory (RCA, 0.80+/-0.06 vs 0.78+/-0.06, P=0.28). The analysis of the reversibility of stress induced perfusion defects yielded a global agreement between protocols of 93% (kappa=0.42). The differences were due to the expert readers, using the gated stress-only protocol, misinterpreting some patients with attenuation artefacts, subendocardial infarction and functional stunning. These results show that the lower cost gated stress-only myocardial Tc myocardial perfusion SPECT studies are comparable to the conventional dual isotope studies when the clinical question is the detection and localization of coronary artery disease. Nevertheless, we also showed that this approach is limited when attempting to interpret the reversibility of stress induced perfusion defects in patients who exhibit attenuation artefacts, subendocardial infarction and functional stunning.

Evaluation of left ventricular endocardial volumes and ejection fractions computed from gated perfusion SPECT with magnetic resonance imaging: comparison of two methods.

BACKGROUND: Two methods of computing left ventricular volumes and ejection fraction (EF) from 8-frame gated perfusion single photon emission computed tomography (SPECT) were compared with each other and with magnetic resonance (MR) imaging. METHODS AND RESULTS: Thirty-five subjects underwent 8-frame gated dual-isotope SPECT imaging and 12- to 16-frame gated MR imaging. Endocardial boundaries on short-axis MR images were hand traced by experts blinded to any SPECT results. Volumes and EF were computed with the use of Simpson's rule. SPECT images were analyzed for the same functional variables with the use of 2 automatic programs, Quantitative Gated SPECT (QGS) and the Emory Cardiac Toolbox (ECTb). The mean difference between MR and SPECT EF was 0.008 for ECTb and 0.08 for QGS. QGS showed a slight trend toward higher correlation for EF (r = 0.72, SE of the estimate = 0.08) than ECTb (r = 0.70, SE of the estimate = 0.09). For both SPECT methods, left ventricular volumes were similarly correlated with MR, although SPECT volumes were higher than MR values by approximately 30%. CONCLUSIONS: QGS and ECTb values of cardiac function computed from 8-frame gated perfusion SPECT correlate very well with each other and correlate well with MR. Averaged over all subjects, ECTb measurements of EF are not significantly different from MR values but QGS significantly underestimates the MR values.

Diagnostic performance of an expert system for the interpretation of myocardial perfusion SPECT studies.

UNLABELLED: An expert system (PERFEX) developed for the computer-assisted interpretation of myocardial perfusion SPECT studies is now becoming widely available. To date, a systematic validation of the diagnostic performance of this expert system for the interpretation of myocardial perfusion SPECT studies has not been reported. METHODS: To validate PERFEX's ability to detect and locate coronary artery disease (CAD), we analyzed 655 stress/rest myocardial perfusion prospective SPECT studies in patients who also underwent coronary angiography. The patient population comprised CAD patients (n = 480) and healthy volunteers (n = 175) (449 men, 206 women). Data from 461 other patient studies were used to implement and refine 253 heuristic rules that best correlated the presence and location of left ventricular myocardial perfusion defects on SPECT studies with angiographically detected CAD and with human expert visual interpretations. Myocardial perfusion defects were automatically identified as segments with counts below sex-matched normal limits. PERFEX uses the certainty of the location, size, shape, and reversibility of the perfusion defects to infer the certainty of the presence and location of CAD. The visual interpretations of tomograms and polar maps, vessel stenosis from coronary angiography, and PERFEX interpretations were all accessed automatically from databases and were used to automatically generate comparisons between diagnostic approaches. RESULTS: Using the physician's reading as a gold standard, PERFEX's sensitivity and specificity levels for detection and localization of disease were, respectively, 83% and 73% for CAD, 76% and 66% for the left anterior descending artery, 90% and 70% for the left circumflex artery, and 74% and 79% for the right coronary artery. These results were extracted from a receiver operating characteristic curve using the average optimal input certainty factor. CONCLUSION: This study shows that the diagnostic performance of PERFEX for interpreting myocardial perfusion SPECT studies is comparable with that of nuclear medicine experts in detecting and locating CAD.

Synchronous oral leiomyosarcoma and squamous cell carcinoma.

An unusual case of synchronous squamous cell carcinoma and leiomyosarcoma of the oral cavity is reported in a patient without any identified environmental risk or predisposing factors. The invasive squamous cell carcinoma involved the tongue, whereas the leiomyosarcoma was located in the soft palate. No immunostaining was found for human papillomavirus or Epstein-Barr virus, and in situ hybridization showed negativity for human papillomavirus DNA within the tumor cells. Alterations of bcl -2, c-erb -b2 and Rb oncoproteins were not found immunohistochemically. Overexpression of p53 was detected by immunohistochemistry in both tumors, but p53 gene mutations were not found by polymerase chain reaction. Neither loss of heterozygosity of p53 nor microsatellite instability was detected in this patient. The smooth muscle nature of the leiomyosarcoma was confirmed by immunohistochemical methods. To our knowledge, synchronous smooth muscle and epithelial oral tumors have not previously been reported.

Morphological and agronomical diversity patterns in the Spanish barley core collection.

Seven thousand years of barley cultivation under the environmental hardships typical of the Mediterranean climate have generated genetic singularity of the Spanish barleys, consistently reported in the literature. From the Spanish National Collection of 2289 accessions, a core subset with 159 landraces and 16 old varieties was constituted. Twenty-seven characters were evaluated for the core collection, to define the structure of the diversity. Several evaluation trials were carried out in 1999-2000, whereas yield trials were performed in earlier years. Phenotypic diversity was large for most of the characters studied. Comparisons of genetic diversity between the core and the original collections suggested that the core is a good representation of the existing diversity in the BNG. Comparisons with results of studies on Spanish materials from other collections seem to indicate that the Spanish diversity is not well represented in some world collections. Principal component analyses for quantitative and qualitative characters revealed a clear distinction between two- and six-row cultivars, and also between landraces and commercial varieties. Geographical origins of the landraces were correlated with grain yield, heading date, duration of grain filling period, and growth class. In relation to diseases, altitude played an important role on the resistance to powdery mildew and brown rust. For brown rust, all the resistant landraces came from low altitudes. These geographical gradients seemed consistent with prior knowledge about barley adaptation, and would confirm the agreement between passport data and true adaptive origin of these landraces from a geographical point of view.

Echocardiographic validation of gated SPECT ventricular function measurements.

UNLABELLED: Left ventricular (LV) volumes are valuable prognostic indicators in the management of coronary artery disease and traditionally have been obtained by x-ray contrast angiography or echocardiography. There now are several scintigraphic methods to compute volumes that are based on different LV modeling assumptions. Both the reasons that calculations from different nuclear techniques can disagree with one another and the relationship of these values to the more conventional echocardiographic measurements must be investigated thoroughly for calculations to be interpretable for individual patients. METHODS: Echocardiographic volumes were determined in 33 retrospective subjects with coronary artery disease (mean age, 61 +/- 12 y; 42% men; 70% with abnormal perfusion and 58% with abnormal segmental wall motion) using the modified Simpson's rule technique applied to digitized apical 4-chamber and apical 2-chamber views of 4 averaged heartbeats. These volumes were compared with those from 3 gated SPECT methods based on Simpson's rule LV modeling similar to standard echocardiographic algorithms (SPECT EF from St. Luke's-Roosevelt Hospital) (method 1), Gaussian myocardial count profile curve fitting (QGS from Cedars-Sinai Medical Center) (method 2), and an endocardial model based on perfusion sampling and count-based thickening (Cardiac Toolbox from Emory University) (method 3). RESULTS: By ANOVA, there were no significant differences among ejection fractions (EFs), but there were for volumes. Paired t test analysis showed volumes from methods 2 and 3 to be significantly larger than echocardiographic volumes and larger than those of method 1. Linear regression analysis comparing gated SPECT and echocardiographic volumes showed a nearly identical strong correlation (r = 0.92; P < 0.000001) for all 3 methods. Excellent correlation also was found among gated SPECT volumes from the 3 methods (r = 0.94). Bland-Altman analysis and t tests showed that method 1 volumes (70 +/- 61 mL) were the same as for echocardiography (77 +/- 55 mL), but volumes were overestimated by method 2 (105 +/- 74 mL) and method 3 (127 +/- 92 mL), particularly for larger volumes. Pearson coefficients for EFs compared with echocardiography were r = 0.82, 0.75, and 0.72 for methods 1-3, respectively. EFs correlated strongly among the 3 gated SPECT methods (r = 0.86-0.92). The Fisher z test showed no differences among these methods for any of the volume or EF linear correlation analyses. CONCLUSION: All gated SPECT parameters correlated well with echocardiographic values. However, the gated SPECT method for which underlying assumptions most closely resembled those commonly used in echocardiography produced mean volume values closest in agreement with echocardiographic measurements.

Three-dimensional color-modulated display of myocardial SPECT perfusion distributions accurately assesses coronary artery disease.

UNLABELLED: The objective of this study was to compare visual assessment of 3-dimensional color-modulated (to counts) surface displays with visual assessment of oblique tomographic slices of myocardial SPECT perfusion distributions in the detection and localization of coronary artery disease (CAD). METHODS: Sixty-two consecutive patients (41 men, 21 women; mean age, 61 +/- 11 y) who had undergone conventional dual-isotope perfusion SPECT were retrospectively chosen; 50 had undergone coronary arteriography previously, and 12 had less than a 5% likelihood of CAD. Four readers interpreted the 3-dimensional displays and slices in separate sessions while unaware of the findings of previous readings, the interpretations of others, and the angiographic results. The readers used a 5-point scoring system. Their average score was used for receiver operating characteristic (ROC) analysis. The area under the ROC curves was determined so that the ability of the 2 methods to detect and localize CAD could be compared. RESULTS: No significant differences were found between visual interpretation of 3-dimensional displays and visual interpretation of slices. CONCLUSION: These preliminary results indicate that visual interpretation of 3-dimensional displays of myocardial perfusion SPECT distributions may someday replace visual assessment of conventional slices without loss of diagnostic accuracy.

Improved detection of myocardial perfusion reversibility by rest-nitroglycerin Tc-99m-MIBI: comparison with TI-201 reinjection.

BACKGROUND: The role of nitroglycerin (NTG) in Tc-99m-methoxyisobutil isonitrile (MIBI) studies to improve the assessment of myocardial viability in patients with coronary artery disease and its comparison with TI-201 reinjection has not yet been clarified. This study aimed to test whether sublingual administration of NTG could improve the capability of Tc-99m-MIBI to detect reversibility in exercise-induced perfusion defects and to compare it with the TI-201 stress-redistribution-reinjection protocol. METHODS AND RESULTS: Thirty-eight patients (33 men, 5 women; mean age 49.3 +/- 8.2 years with previous myocardial infarction [mean evolution 7.1 +/- 3.9 months]) underwent exercise, redistribution, and reinjection TI-201 imaging, as well as exercise, rest, and NTG MIBI myocardial scintigraphy (3-day protocol). A total of 494 myocardial segments were assessed by quantitative analysis. Of the 136 myocardial segments with fixed defects on exercise-rest sestamibi imaging, 109 (80%) did not change after NTG MIBI study, and 27 (20%) demonstrated enhanced uptake. In the 140 myocardial segments with fixed defects on exercise-redistribution thallium imaging, 112 (80%) did not improve after TI-201 reinjection study, and 28 (20%) showed increased activity. The observed agreement on reversibility detection between NTG MIBI and TI-201 reinjection, with the 210 segments with perfusion defects used for this analysis on both studies, was 78%, with a significant kappa = .56 +/- .07 SE. CONCLUSION: Our data suggest that the use of an NTG MIBI protocol results in an incremental improvement for detecting exercise-induced perfusion defect reversibility and achieves results similar to those from a TI-201 reinjection protocol.

Attenuation and scatter compensation in myocardial perfusion SPECT.

Nonuniform attenuation, Compton scatter, and limited, spatially varying resolution degrade both the qualitative and quantitative nature of myocardial perfusion SPECT. Physicians must recognize and understand the effects of these factors on myocardial perfusion SPECT for optimal interpretation and use of this important imaging technique. Recent developments in the design and implementation of compensation algorithms and transmission-based imaging promise to provide clinically realistic solutions to these effects and provide the framework for truly quantitative imaging. This achievement should improve the diagnostic accuracy and cost-effectiveness of myocardial perfusion SPECT.