Number Of Perfusion Defects Research Articles

Lung Ventilation/Perfusion Scintigraphy for the Screening of Chronic Thromboembolic Pulmonary Hypertension (CTEPH): Which Criteria to Use?

ObjectiveThe diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) is a major challenge as it is a curable cause of pulmonary hypertension (PH). Ventilation/Perfusion (V/Q) lung scintigraphy is the imaging modality of choice for the screening of CTEPH. However, there is no consensus on the criteria to use for interpretation. The aim of this study was to assess the accuracy of various interpretation criteria of planar V/Q scintigraphy for the screening of CTEPH in patients with PH.MethodsThe eligible study population consisted of consecutive patients with newly diagnosed PH in the Brest University Hospital, France. Final diagnosis (CTEPH or non-CTEPH) was established in a referential center on the management of PH, based on the ESC/ERS guidelines and a minimum follow-up of 3 years. A retrospective central review of planar V/Q scintigraphy was performed by three nuclear physicians blinded to clinical findings and to final diagnosis. The number, extent (sub-segmental or segmental) and type (matched or mismatched) of perfusion defects were reported. Sensitivity and specificity were evaluated for various criteria based on the number of mismatched perfusion defects and the number of perfusion defects (regardless of ventilation). Receiver operating characteristic (ROC) curves were generated and areas under the curve (AUC) were calculated for both.ResultsA total of 226 patients with newly diagnosed PH were analyzed. Fifty six (24.8%) were diagnosed with CTEPH while 170 patients (75.2%) were diagnosed with non-CTEPH. The optimal threshold was 2.5 segmental mismatched perfusion defects, providing a sensitivity of 100 % (95% CI 93.6–100%) and a specificity of 94.7% (95%CI 90.3–97.2%). Lower diagnostic cut-offs of mismatched perfusion defects provided similar sensitivity but lower specificity. Ninety five percent of patients with CTEPH had more than 4 segmental mismatched defects. An interpretation only based on perfusion provided similar sensitivity but a specificity of 81.8% (95%CI 75.3–86.9%).ConclusionOur study confirmed the high diagnostic performance of planar V/Q scintigraphy for the screening of CTEPH in patients with PH. The optimal diagnostic cut-off for interpretation was 2.5 segmental mismatched perfusion defects. An interpretation only based on perfusion defects provided similar sensitivity but lower specificity.

The Role of Myocardial Perfusion Imaging in Patients with Diabetes Mellitus

Abstract Diabetes mellitus is a complex pathology with increasing incidence, associated with an increased risk of coronary heart disease. Myocardial perfusion imaging (MPI) is an important diagnostic tool for the evaluation of coronary artery disease (CAD), with a high prognostic value. Objective. The aim of this study was to evaluate the role of stress-rest MPI in the assessment of patients with DM and suspected or confirmed CAD. Method. We performed a retrospective analysis of 128 patients who underwent stress-rest MPI in our department, all of them with coronary angiography (CA) available. All patients underwent stress rest myocardial perfusion SPECT using a 1-day or 2-day protocol. The radiopharmaceuticals used were 99m-Tc-MIBI or tetrofosmin. The study was performed with a gated protocol SPECT, synchronous with the ECG, using a dual-head gamma camera. Patients were divided in 4 subgroups based on the presence of DM and of significant CA changes. Results. In the group of patients with significant coronary disease on CA and previously diagnosed DM, number of perfusion defects on the stress-rest MPI were higher and also the presence of systolic disfunction and the severity of defects. Our results support the idea that the severity and extent of myocardial perfusion defects are greater in diabetic patients than in non-diabetic patients. Conclusions. We can consider myocardial perfusion SPECT with 99mTc-labeled agents as a feasible method for the diagnosis and evaluation of CAD and for the management of diabetic patients.

Comparison of cardiac MR and 201 Thallium spect in evaluation of myocardial perfusion and viability in coronary artery disease

To compare 201Tl (201-Thallium) single photon emission CT (SPECT) and cardiac MRI (cMRI) for identifying regions of reversible myocardial dysfunction. We conducted an experimental study to compare both modalities by finding the area under ROC curve and coefficient of variability in 42 cases (714 cardiac segments) after a pilot study on 16 cases. We also compared the two modalities by an ingenious method validated in pilot study with common physiological variable, regional wall motion abnormality vs viability assessed independently by both the modalities. The correlation coefficient in the detection of perfusion defects by both the diagnosing modalities was 0.89 and diagnostic region of operating characteristics was 0.97. The sensitivity was 0.96 by 201Tl-SPECT and 0.98 by cMRI, whereas the specificity 0.84 by 201Tl-SPECT and 0.85 by cMRI. The positive and negative predictive value was 0.95 and 0.85 by 201Tl-SPECT, 0.97 and 0.90 by cMRI, respectively. The accuracy of evaluating the viability was 93.15 and 95.69 by the 201Tl-SPECT and cMRI respectively with a ‘p’ value of <0.0001. The study shows a good sensitivity and correlation of both 201Tl-SPECT and cMRI in diagnosing the extent and number of perfusion defects in the myocardium. cMRI is more accurate than 201Tl-SPECT in not only diagnosing myocardial infarcts but also shows its exact location and extent; this is likely to be of use in patients with equivocal 201Tl-SPECT studies. The results were concordant with the other international studies. This is one of the largest study ever carried on comparison of these two modalities.

Flow-mediated vasodilation predicts the presence and extent of coronary artery disease assessed by stress thallium imaging

Endothelial function can be measured by flow-mediated vasodilation (FMD) of the brachial artery and has been associated with cardiac risk factors (RF) and angiographically defined coronary artery disease (CAD). Stress single photon emission computed tomography (SPECT) imaging is commonly used to study patients with CAD. We sought to study the relationship between endothelial dysfunction by FMD and stress thallium SPECT to detect CAD. Fifty-five consecutive patients with chest pain syndrome referred for stress SPECT and eleven healthy control subjects had FMD measured on the brachial artery by standard techniques. The main outcome was the percent of brachial artery diameter dilation from baseline and the number of perfusion defects by SPECT. In subjects with no RF, those with RF but no defects, and those with defects, the mean FMD was 18.88% +/- 2.31%, 7.85% +/- 1.66%, and 5.91% +/- 1.07%, respectively (P < .05). A significant correlation was found between the number of thallium defects and degree of FMD impairment (r = -0.40, P < .01). An FMD cutoff value of less than 7.5% had a 72.5% sensitivity and 73.1% specificity in predicting the presence of any thallium defects. After RF adjustment, FMD remained as the strongest predictor of scintigraphic CAD (odds ratio, 10.96; 95% confidence interval, 2.82-57.31). FMD independently predicts the presence and extent of scintigraphic CAD.

QT dispersion in the risk stratification of patients with unstable angina: correlation with clinical course, troponin T and scintigraphy

Objective — This study sought to evaluate the potential prognostic usefulness of QT dispersion (QTd) in patients with unstable angina.Methods and results — QTd was calculated and plasma troponin T (TnT) level was measured and rest perfusion imaging with Tc-99m sestamibi was performed in 62 patients admitted with chest pain at rest. All patients had a follow-up during one month in order to assess cardiac events. Cardiac events occurred in 41 patients (no deaths, 11 myocardial infarctions (MI), 4 urgent and 26 planned revascularizations).The mean QTd in patients with cardiac events was significantly higher than in those without cardiac events (68 ± 28 vs. 54 ± 14 ms; p = 0.01).When patients were divided into subgroups according to the cardiac events, the mean QTd in MI and revascularization were 90 ± 25 ms and 60 ± 25 ms, respectively. QTd in patients with MI was higher than in patients without cardiac events (p = 0.001). There was no significant difference in QTd between the revascularization subgroup and patients without cardiac events. Nineteen patients with elevated TnT had a greater QTd compared to patients with normal TnT (74 ± 29 vs. 56 ± 20 ms; p = 0.008). Additionally, the mean QTd in 46 patients with perfusion defects was slightly higher than in patients without (66 ± 27 vs. 53 ± 17 ms; p = 0.03).There was also a moderate correlation between QTd and the number of perfusion defects (r = 0.31, p = 0.01). On the other hand, most of the patients who had a MI or urgent revascularization had a QTd greater than 75 ms.Conclusion — The measurement of QTd in patients with unstable angina may help to stratify patients at high risk for cardiac events, in particular MI and urgent revascularization.

Transmyocardial Laser Revascularization as Sole Therapy in Coronary Disease

This prospective study evaluated the medium-term efficacy of transmyocardial laser revascularization as the sole therapy in patients with ischemic heart disease. A carbon dioxide laser was used to create channels through ischemic areas of the myocardium in 33 patients with a mean age of 58.8 ± 10.4 years. The mean left ventricular ejection fraction determined by echocardiography was 44.8% ± 14%. Preoperatively, the patients underwent coronary artery angiography, single photon emission computed tomography perfusion scans, and positron emission tomography metabolism scans to determine the extent and severity of ischemia and myocardial viability. Total follow-up of 327 patient-months was obtained for 26 patients with a mean follow-up of 12.6 ± 9 months. The scans were repeated at 3, 6, 12, and 24 months postoperatively. The perioperative mortality was 9% due to ventricular fibrillation. Morbidity was minimal. The number of perfusion defects decreased significantly after treatment and there was a significant increase in myocardial viability in the treated left ventricular free wall. The success rate, defined as a decrease of 2 angina classes, was approximately 80% during the follow-up, reflected in a significant decrease in the number of admissions for angina in the year after the procedure (mean, 0.5 ± 0.4) compared with the previous year (mean, 2 ± 1.1) and in decreased use of antianginal medications.

Transmyocardial laser revascularization: Results of a multicenter trial with transmyocardial laser revascularization used as sole therapy for end-stage coronary artery disease

Background: Transmyocardial laser revascularization was used as the sole therapy for patients with ischemic heart disease not amenable to percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. This technique uses a carbon dioxide laser to create transmyocardial channels for direct perfusion of the ischemic heart. Methods: Since 1992, 200 patients, at eight hospitals in the United States, have undergone transmyocardial laser revascularization. The patients have a combined 1560 months of follow-up for an average of 10 ± 3 months per patient. Their age was 63 ± 10 years and their ejection fraction was 47% ± 12%. Eighty-two percent had at least one previous bypass graft operation and 38% had a prior angioplasty. Preoperatively, the patients underwent nuclear single photon emission computed tomography perfusion scans to identify the extent and severity of their ischemia. These scans were repeated at 3, 6, and 12 months. Angina class, admissions for angina, and medications were recorded. Results: The perioperative mortality was 9%. Angina class decreased significantly from before treatment to 3, 6, and 12 months ( p < 0.001). Likewise, there was a significant decrease in the number of perfusion defects in the treated left ventricular free wall. Concomitantly, there was a significant decrease in the number of admissions for angina in the year after the procedure when compared with the year before treatment (2.5 vs 0.5 admissions per patient-year). Conclusion: These combined results indicate that transmyocardial laser revascularization provides angina relief, decreases hospital admissions, and improves perfusion in patients with severe coronary artery disease. (J Thorac Cardiovasc Surg 1997;113:645-54)

Assessment of myocardial viability by dynamic tomographic iodine 123 iodophenylpentadecanoic acid imaging: Comparison with rest-redistribution thallium 201 imaging

This study examined the ability of dynamic 123I-labeled iodophenylpentadecanoic acid (IPPA) imaging to detect myocardial viability in patients with left ventricular (LV) dysfunction caused by coronary artery disease. Serial 180-degree single-photon emission computed tomographic (SPECT) images (five sets, 8 minutes each) were obtained starting 4 minutes after injection of 2 to 6 mCi 123I at rest in 21 patients with LV dysfunction (ejection fraction [EF] 34% +/- 11%). The segmental uptake was compared with that of rest-redistribution 201Tl images (20 segments/study). The number of perfusion defects (reversible and fixed) was similar by IPPA and thallium (11 +/- 5 vs 10 +/- 5 segments/patient; difference not significant). There was agreement between IPPA and thallium for presence or absence (kappa = 0.78 +/- 0.03) and nature (reversible, mild fixed, or severe fixed) of perfusion defects (kappa = 0.54 +/- 0.04). However, there were more reversible IPPA defects than reversible thallium defects (7 +/- 4 vs 3 +/- 4 segments/patient; p = 0.001). In 14 patients the EF (by gated pool imaging) improved after coronary revascularization from 33% +/- 11% to 39% +/- 12% (p = 0.002). The number of reversible IPPA defects was greater in the seven patients who had improvement in EF than in the patients without such improvement (10 +/- 4 vs 5 +/- 4 segments/patient; p = 0.075). 123I-labeled IPPA SPECT imaging is a promising new technique for assessment of viability. Reversible defects predict recovery of LV dysfunction after coronary revascularization.

The usefulness of the posterior oblique views in perfusion lung imaging.

A total of 116 perfusion lung images, with and without posterior oblique views, were compared by four trained observers. There was a significant increase in the number of perfusion defects detected when the posterior oblique views were included. Pairs of projections of 89 lung images were read by the four observers. The percentage of correct readings for the posterior oblique views was 78% compared with 63% and 56% for the lateral views and AP views, respectively. Inclusion of the posterior oblique views as a routine part of the examination is recommended.