A comparative assessment of intra- and inter- observer repeatability of three widely used software packages for the quantification of defect size in stress myocardial perfusion scintigraphy.

OBJECTIVE: To assess the intra- and inter-observer repeatability of popular software packages for the quantitative determination of abnormality size in stress myocardial perfusion scintigraphy. SUBJECTS AND METHODS: A total of 182 tomographic stress myocardial perfusion scans were processed in duplicate by an experienced and trainee observer to assess SSSext (summed stress score multiplied by 100/68) and total defect extent (TDE), as % of the left ventricle, with 4 dimension-myocardial (4DM), emory cardiac toolbox (ECTb) and quantitative perfusion SPECT (QPS) packages. The Bland-Altman (B-A) analysis and Lin's concordance correlation coefficient (CCC) were used to assess agreement. RESULTS: In SSSext's intra-observer repeatability, CCC showed substantial agreement for 4DM and QPS, and moderate agreement for ECTb for both observers. In inter-observer repeatability, CCC revealed substantial agreement for 4DM and QPS, and poor agreement for ECTb. Regarding TDE, CCC showed substantial intra-observer repeatability for both operators using all packages, while the inter-observer repeatability was substantial for 4DM and QPS, and moderate for ECTb.In SSSext's intra-observer repeatability for 4DM, ECTb and QPS, the B-A analysis provided (mean±1.96SD of paired measurements) 0.0±4.3, 0.2±7.8, -0.6±7.6 for the experienced physician and 0.2±5.9, 0.0±7.5, -0.5±5.4 for the trainee, respectively; in inter-observer repeatability it provided 0.2±5.4, 0.1±9.6, 0.2±8.1, respectively. Regarding TDE, the B-A values for intra-observer repeatability were 0.1±5.2, 0.1±7.9, 0.1±2.8 for the experienced reader and 0.3±6.6, -0.1±6.4, -0.1±2.4 for the trainee, respectively; in inter-observer agreement the B-A provided 0.6±6.4, -0.2±10.3, -0.1±4.3, respectively. CONCLUSION: Considerable differences in intra- and inter- observer agreement were noted for the quantitative determination of defect size using widely employed software packages, suggesting limitations in the clinical use of these measurements. Quantitative perfusion SPECT appears preferable, but with no significant advantage over 4DM. There were no significant differences between the observers.

Equilibrium radionuclide angiography: Intra- and inter-observer repeatability and reproducibility in the assessment of cardiac systolic and diastolic function.

BACKGROUND: This study aimed to assess intra- and inter-observer agreement in assessing the systolic and diastolic function with equilibrium radionuclide angiography (ERNA). MATERIALS AND METHODS: Thirty-two adults underwent baseline and repeat ERNA. An experienced and a trainee operator analyzed the data by assigning regions of interest manually, fully automatically, and semi-automatically. The Bland-Altman statistic (mean ± 1.96 standard deviations of the differences) was used to assess the repeatability (two different assessments of a single acquisition) and reproducibility (assessments of two different acquisitions). RESULTS: Using the semi-automated technique the intraobserver repeatability and reproducibility of left ventricular ejection fraction for the experienced physician were - 0.1 ± 3.7 and 0.0 ± 3.8 and for the trainee 2.2 ± 10.6 and 1.9 ± 8.4, respectively. The inter-observer repeatability and reproducibility were - 1.8 ± 6.4 and 0.4 ± 9.0, respectively. Among the parameters of diastolic function, the intraobserver repeatability and reproducibility of the peak filling rate for the experienced physician were - 0.0 ± 1.1 and - 0.1 ± 1.1 and for the trainee 0.2 ± 3.5 and 0.4 ± 3.7, respectively. The inter-observer repeatability and reproducibility were 0.3 ± 1.5 and 0.5 ± 4.0, respectively. Similar was the pattern for the other diastolic indices. In all cases the limits of agreement varied according to the quantification approach. CONCLUSION: A good repeatability but a moderate reproducibility was found in the assessment of the LVEF. Less good were the findings in the assessment of diastolic function.

Determination of the glomerular filtration rate in patients with type 2 diabetes: An assessment of the agreement between 51Cr-EDTA plasma clearance and 99mTc-DTPA plasma clearance, 99mTc-DTPA renography and plasma creatinine prediction equation.

AIMS: To investigate the agreement of glomerular filtration rate (GFR) determination between 51Cr-ethylenediaminetetraacetic acid (51Cr-EDTA) plasma clearance (GFREDTA) and 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) plasma clearance (GFRDTPA), the Gates 99mTc-DTPA renographic method (GFRGates) and the serum creatinine Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI, GFRSCr) in patients with type 2 diabetes mellitus (T2DM). METHODS: Ninety-nine T2DM patients underwent GFR determinations simultaneously with 51Cr-EDTA and 99mTc-DTPA (using the slope-intercept technique and the Brochner-Mortensen correction) and also with GFRGates and GFRSCr. RESULTS: In the comparison between GFREDTA versus GFRDTPA, GFRGates and GFRSCr, the Bland-Altman statistic provided 0.0 ± 13.2, 17.4* ± 28.8 and -5.9* ± 30.1 (*p < 0.001 for the difference from 0). Lin's concordance correlation coefficient showed substantial (0.976), poor (0.737) and poor (0.872) agreement, respectively. The proportion of the index results within the 30% and 10% of GFREDTA measurements were 95% and 74% for GFRDTPA, 53% and 19% for GFRGates, and 83% and 26% for GFRSCr, respectively. CONCLUSION: In T2DM patients, a clinically acceptable agreement is demonstrated between 51Cr-EDTA and 99mTc-DTPA plasma clearance for GFR measurements, suggesting conditional interchangeability between those compounds. Both the CKD-EPI prediction equation and the Gates' renographic method cannot assess GFR reliably, the latter appearing less unfailing than the former.

Equilibrium radionuclide ventriculography: still a clinically useful method for the assessment of cardiac function?

18 The non-invasive assessment of left ventricular function with simple indices, such as left ventricular volumes and ejection fraction (LVEF), offers significant diagnostic and prognostic implications in the entire spectrum of cardiac diseases. Equilibrium radionuclide ventriculography (RNV) is a well validated technique for this purpose. Based on the principle that the amount of radioactivity emitted by technetium-99m (99mTc)-pertechnate labeled erythrocytes in the cardiac chambers is proportional to the amount of bloodcontained, reproducible and accurate LVEF measurements can be obtained, with practically no geometric assumptions regarding heart shape. However, the development of other imaging techniques, mostly echocardiography and secondarily cardiac magnetic resonance has led to a decline in the use of RNV. This is due to easiness, cost and availability issues and also because competitive modalities can offer reliable anatomic and functional information and hence they can address a variety of clinical scenarios in one session. Nevertheless, RNV still remains a reliable method in clinical conditions, in which the detection of small changes in LVEF may be important in clinical decision-making, such as in patients undergoing cardiotoxic chemotherapy, when the images of different methods are of suboptimal quality or unobtainable, or there is discordance between clinical judgment and imaging results. In this respect the more recently introduced gated single photon emission tomography (SPET) myocardial perfusion imaging has not demonstrated equivalent reliability, in terms of independence from a variety of factors and accuracy of measurements on a per-patient basis. The purpose of this review is to present the features of RNV, and to define its role in the evaluation of cardiac function in the current era of medical imaging.

A Comparative Assessment of Cardiovascular Autonomic Reflex Testing and Cardiac 123I-Metaiodobenzylguanidine Imaging in Patients with Type 1 Diabetes Mellitus without Complications or Cardiovascular Risk Factors.

AIM: To compare the cardiovascular autonomic reflex tests (CARTs) with cardiac sympathetic innervation imaging with 123I-metaiodobenzylguanidine (MIBG) in patients with type 1 diabetes mellitus (T1DM). PATIENTS AND METHODS: Forty-nine patients (29 males, mean age 36 ± 10 years, mean T1DM duration 19 ± 6 years) without cardiovascular risk factors were prospectively enrolled. Participants were evaluated for autonomic dysfunction by assessing the mean circular resultant (MCR), Valsalva maneuver (Vals), postural index (PI), and orthostatic hypotension (OH). Within one month from the performance of these tests, patients underwent cardiac MIBG imaging and the ratio of the heart to upper mediastinum count density (H/M) at 4 hours postinjection was calculated (abnormal values, H/M < 1.80). RESULTS: Twenty-nine patients (59%) had abnormal CARTs, and 37 (76%) patients had an H/M_4 < 1.80 (p = 0.456). MCR, PI, Vals, and OH were abnormal in 29 (59%), 8 (16%), 5 (10%), and 11 (22%) patients, respectively. When using H/M_4 < 1.80 as the reference standard, a cutoff point of ≥2 abnormal CARTs had a sensitivity of 100% but a specificity of only 33% for determining CAN. CONCLUSIONS: CARTs are not closely associated with 123I-MIBG measurements, which can detect autonomic dysfunction more efficiently than the former. In comparison to semiquantitative cardiac MIBG assessment, the recommended threshold of ≥2 abnormal CARTs to define cardiovascular autonomic dysfunction is highly sensitive but of limited specificity and is independently determined by the duration of T1DM.

Resting electrocardiogram and stress myocardial perfusion imaging in the determination of left ventricular systolic function: an assessment enhancing the performance of gated SPET.

This study aimed to determine systolic dysfunction and estimate resting left ventricular ejection fraction (LVEF) from information collected during routine evaluation of patients with suspected or known coronary heart disease. This approach was then compared to gated single photon emission tomography (SPET). Patients having undergone stress (201)Tl myocardial perfusion imaging followed by equilibrium radionuclide angiography (ERNA) were separated into derivation (n=954) and validation (n=309) groups. Logistic regression analysis was used to develop scoring systems, containing clinical, electrocardiographic (ECG) and scintigraphic data, for the discrimination of an ERNA-LVEF<0.50. Linear regression analysis provided equations predicting ERNA-LVEF from those scores. In 373 patients LVEF was also assessed with (201)Tl gated SPET. Our results showed that an ECG-Scintigraphic scoring system was the best simple predictor of an ERNA-LVEF<0.50 in comparison to other models including ECG, clinical and scintigraphic variables in both the derivation and validation subpopulations. A simple linear equation was derived also for the assessment of resting LVEF from the ECG-Scintigraphic model. Equilibrium radionuclide angiography-LVEF had a good correlation with the ECG-Scintigraphic model LVEF (r=0.716, P=0.000), (201)Tl gated SPET LVEF (r=0.711, P=0.000) and the average LVEF from those assessments (r=0.796, P=0.000). The Bland-Altman statistic (mean+/-2SD) provided values of 0.001+/-0.176, 0.071+/-0.196 and 0.040+/-0.152, respectively. The average LVEF was a better discriminator of systolic dysfunction than gated SPET-LVEF in receiver operating characteristic (ROC) analysis and identified more patients (89%) with a

Yttrium-90 radiation synovectomy in knee osteoarthritis: a prospective assessment at 6 and 12 months.

OBJECTIVE: To assess the outcome of yttrium-90 radiation synovectomy at 6 and 12 months in patients with knee osteoarthritis unresponsive to systematic or local medical treatment. METHODS: Consecutive patients with osteoarthritic knee pain resistant to conventional therapy and submitted to intraarticular yttrium-90 treatment because of synovial inflammation, as demonstrated by early-phase bone scintigraphy, were prospectively evaluated at 6 and/or 12 months. The assessment of the outcome of treatment was based on self-reporting of relief of knee pain limiting daily activities, measured as percentage reduction of the pretherapeutic joint discomfort with a Visual Analogue Scale. Resting and nocturnal pain also were considered, together with knee flexibility and ultrasonographic changes. RESULTS: Among a total of 97 patients, a > or =50% Visual Analogue Scale pain palliation was experienced by 64 of 90 (71.1%) patients at 6 months and 50 of 69 (72.5%) at 12 months (P = 0.992). Moreover, nocturnal and resting pain alleviation, gain in knee flexibility and regression of large joint effusions and Baker's cysts were observed in considerable proportions. In the evaluation of the outcome of treatment in 62 patients with serial assessments using a composite criterion, 42 (67.7%) versus 40 (64.5%) had a satisfactory response at 6 and 12 months, respectively (P = 0.850). The probability of a favourable therapeutic result was inversely related to the severity of radiographic joint changes. CONCLUSION: Yttrium-90 synovectomy exerts a beneficial therapeutic effect in a substantial proportion of patients with osteoarthritic knee pain and synovial inflammation, inadequately controlled by pharmacotherapy. Clinical improvement is inversely related to radiographic knee damage.

201Tl gated single photon emission computed tomographic myocardial perfusion imaging in the assessment of global and regional left ventricular function. Would it be favoured over equilibrium radionuclide angiography?

BACKGROUND: This study investigates the clinical performance of routine 201Tl gated single photon emission computed tomographic (201Tl GSPECT) myocardial perfusion imaging. Equilibrium radionuclide angiography (ERNA) was used as the standard for comparison. METHODS AND RESULTS: One hundred and seventy-two consecutive patients were submitted to both myocardial 201Tl GSPECT imaging, at stress and in redistribution, and ERNA. Left ventricular ejection fractions (LVEF) and regional wall motion were assessed from both stress and redistribution 201Tl GSPECT datasets, and from ERNA. Linear regression analysis showed a good correlation between LVEF calculated by ERNA and 201Tl GSPECT (r=0.73 at stress, r=0.75 in redistribution, P<0.0001). However, the 95% prediction intervals of 201Tl GSPECT LVEF from ERNA LVEF were wide (minimum 35.4% at stress and 33.2% in redistribution). Moreover, a difference in LVEF > or =10% between ERNA and 201Tl GSPECT was found in 26.4% of cases at stress and 28.6% of cases in redistribution. A fair agreement between ERNA and 201Tl GSPECT was found in regional wall motion assessment in segments with normal or mildly reduced tracer uptake (kappa=0.32 at stress and kappa=0.33 in redistribution). In segments with moderately to severely reduced tracer uptake, a moderate agreement was found in regional wall motion assessment between ERNA and 201Tl GSPECT (kappa=0.44 at stress and kappa=0.42 in redistribution). CONCLUSIONS: Left ventricular function may be misinterpreted in a significant proportion of patients if the calculation of LVEF is based on 201Tl GSPECT. Moreover, the evaluation of regional wall motion by 201Tl GSPECT appears unsatisfactory.