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S James Cullom

Publications and source records attributed to S James Cullom.

12 recordsLinked to original sources
PubMed2005

Attenuation correction single-photon emission computed tomography myocardial perfusion imaging.

Clinicians now rely heavily on the results of single-photon emission computed tomography (SPECT) myocardial perfusion imaging for diagnosing coronary disease and for planning therapy. However, the technique is imperfect for these purposes, mainly because of technical limitations, the most prominent of which is the effect of soft-tissue attenuation on apparent tracer distribution. Providers have attempted to compensate for this by a number of indirect approaches. Recently, validated hardware and software solutions for directly correcting image data for soft-tissue attenuation have become widely available commercially. Optimal application requires an understanding of the technical details that differ somewhat from system to system, the quality control prerequisites, knowledge of the importance of the transmission map quality, and how dedicated SPECT and SPECT-computed tomography systems present different challenges. In addition, the clinical literature is expanding rapidly, including studies on diagnostic accuracy, image appearances, quantitative analysis, appropriate patients for attenuation correction, clinical utility, incremental value in relation to ECG-gating, and risk stratification.

Algorithms↗
PubMedDate not supplied

Quantitative Tc-99m sestamibi attenuation-corrected SPECT: development and multicenter trial validation of myocardial perfusion stress gender-independent normal database in an obese population.

BACKGROUND: A gender-independent stress normal database and criteria for abnormality for attenuation-corrected rest-stress technetium 99m sestamibi same-day myocardial perfusion imaging were developed by evaluation of 112 patients, validated against an obese population of 95 patients from four different clinical sites, and compared with conventional gender-matched database quantification of non-attenuation-corrected studies. METHODS AND RESULTS: These 95 validation patients (63 men) were used for prospective quantitative evaluation (mean weight, 213 +/- 57 lb; mean body mass index, 32 +/- 9 kg/m(2)). This group included 21 patients (12 men) with a lower than 5% likelihood of coronary artery disease (mean weight, 226 +/- 72 lb; mean body mass index, 34 +/- 13 kg/m(2)) and 74 who underwent cardiac catheterization within 2 months (35 with normal coronaries or coronary lesions <70%). These studies were processed twice, once by use of conventional reconstruction and gender-specific database quantification and a second time by use of attenuation correction and a single gender-independent attenuation-corrected normal database. The attenuation-corrected normal database and criteria for abnormality were developed by evaluation of 48 and 78 patients, respectively. No statistically significant differences were found when comparing attenuation-corrected perfusion distributions of normal men and women, whereas significant differences were found in the same uncorrected studies. Compared with quantitative analysis of the uncorrected studies, quantitative analysis of the attenuation-corrected studies by use of a gender-independent normal database demonstrated a significant improvement in normalcy rate (90% vs 52%, P =.006) and specificity (57% vs 29%, P =.015) in this obese population at no significant loss in sensitivity (90% vs 97%, P = not significant). CONCLUSION: Attenuation-corrected studies can be quantified with a single gender-independent normal database and a single criterion for abnormality without loss of sensitivity and with significantly better specificity and normalcy rate.

Coronary Artery Disease↗
PubMedDate not supplied

Clinical value of attenuation correction in stress-only Tc-99m sestamibi SPECT imaging.

BACKGROUND: Attenuation artifact remains a substantial limitation to confident interpretation of images and reduces laboratory efficiency by requiring comparison of stress and rest image sets. Attenuation-corrected stress-only imaging has the potential to ameliorate these limitations. METHODS AND RESULTS: Ten experienced nuclear cardiologists independently interpreted 90 stress-only electrocardiography (ECG)-gated technetium 99m sestamibi images in a sequential fashion: myocardial perfusion imaging (MPI) alone, MPI plus ECG-gated data, and attenuation-corrected MPI with ECG-gated data. Images were interpreted for diagnostic certainty (normal, probably normal, equivocal, probably abnormal, abnormal, and perceived need for rest imaging). With stress MPI data alone, only 37% of studies were interpreted as definitely normal or abnormal, with a very high perceived need for rest imaging (77%). The addition of gated data did not alter the interpretations. However, attenuation-corrected data significantly increased the number of studies characterized as definitely normal or abnormal (84%, P <.005) and significantly reduced the perceived need for rest imaging (43%, P <.005). These results were confirmed by use of a nonsequential consensus interpretation of three readers. CONCLUSION: Attenuation correction applied to studies with stress-only Tc-99m ECG-gated single photon emission computed tomography images significantly increases the ability to interpret studies as definitely normal or abnormal and reduces the need for rest imaging. These findings may improve laboratory efficiency and diagnostic accuracy.

Adult↗
PubMedDate not supplied

Value of attenuation correction on ECG-gated SPECT myocardial perfusion imaging related to body mass index.

BACKGROUND: Obesity is a growing problem in the United States, and attenuation artifacts are more prevalent in this patient group. This study evaluated the impact of attenuation correction in patients with a high body mass index (BMI). METHODS AND RESULTS: Three readers interpreted gated attenuation-corrected and non-attenuation-corrected rest/stress technetium 99m sestamibi myocardial perfusion imaging results in 116 patients (BMI <30, n = 60; BMI > or =30, n = 56) who had coronary angiography no more than 60 days after imaging. Readers were blinded to all clinical information and as to whether myocardial perfusion imaging was attenuation-corrected or non-attenuation-corrected. Sensitivity, specificity, and accuracy for detection of coronary artery disease of 70% or greater for attenuation-corrected versus non-attenuation-corrected single photon emission computed tomography (SPECT) were 86% versus 89%, 79% versus 50%, and 84% versus 79%, respectively. Sensitivity, specificity, and accuracy for attenuation-corrected versus non-attenuation-corrected SPECT for patients with BMI less than 30 were 90% versus 90%, 82% versus 64%, and 88% versus 85%, respectively. For BMI of 30 or greater, the results were 82% versus 87%, 76% versus 41%, and 80% versus 73%, respectively. There was a significant difference in specificity overall ( P = .02) and for the category of BMI of 30 or greater ( P = .03). CONCLUSIONS: This study demonstrates that electrocardiography-gated attenuation-corrected Tc-99m sestamibi SPECT myocardial perfusion imaging improves specificity compared with electrocardiography-gated non-attenuation-corrected SPECT myocardial perfusion imaging, especially in patients with BMI of 30 or greater.

Artifacts↗
PubMedDate not supplied

Transmission scan truncation with small-field-of-view dedicated cardiac SPECT systems: impact and automated quality control.

BACKGROUND: Small-field-of-view (FOV) dedicated cardiac single photon emission computed tomography (SPECT) systems will frequently exhibit severe transmission scan truncation that may degrade attenuation correction (AC). This study evaluated the impact of transmission scan truncation on AC and developed automated transmission scan truncation quality control (ATSTQC) for small-FOV systems. METHODS AND RESULTS: Small-FOV data were simulated from the data of 10 patients acquired by a full-FOV Philips Vertex system. AC images of the full- and small-FOV data were compared by mean and maximum absolute differences of myocardial counts, and differences in stress and rest severity scores were calculated by use of the Emory Cardiac Toolbox.small-FOV systems. ATSTQC was developed to identify critical truncation that significantly increased these indices and then tested with 18 independent patients. Left-side truncation resulted in significant distortion of the quantitative indices. ATSTQC, developed on the condition that left-side truncation is critical, showed high concordance with the qualitative assessment in identification of critical truncation. CONCLUSIONS: Identification of left-side truncation as critical truncation is necessary to judge whether accurate AC can be obtained. The developed ATSTQC can accurately detect critical truncation and will help clinicians decide whether to use AC in a particular study.

Artifacts↗
PubMedDate not supplied

Diagnostic accuracy of rest/stress ECG-gated Rb-82 myocardial perfusion PET: comparison with ECG-gated Tc-99m sestamibi SPECT.

BACKGROUND: Although single photon emission computed tomography (SPECT) and positron emission tomography (PET) myocardial perfusion imaging (MPI) have evolved considerably over the last decade, there is no recent comparison of diagnostic performance. This study was designed to assess relative image quality, interpretive confidence, and diagnostic accuracy by use of contemporary technology and protocols. METHODS AND RESULTS: By consensus and without clinical information, 4 experienced nuclear cardiologists interpreted 112 SPECT technetium-99m sestamibi and 112 PET rubidium-82 MPI electrocardiography (ECG)-gated rest/pharmacologic stress studies in patient populations matched by gender, body mass index, and presence and extent of coronary disease. The patients were categorized as having a low likelihood for coronary artery disease (27 in each group) or had coronary angiography within 60 days. SPECT scans were acquired on a Cardio-60 system and PET scans on an ECAT ACCEL scanner. Image quality was excellent for 78% and 79% of rest and stress PET scans, respectively, versus 62% and 62% of respective SPECT scans (both p<.05). An equal percent of PET and SPECT gated images were rated excellent in quality. Interpretations were definitely normal or abnormal for 96% of PET scans versus 81% of SPECT scans (p=.001). Diagnostic accuracy was higher for PET for both stenosis severity thresholds of 70% (89% vs 79%, p=.03) and 50% (87% vs 71%, p=.003) and was higher in men and women, in obese and nonobese patients, and for correct identification of multivessel coronary artery disease. CONCLUSION: In a large population of matched pharmacologic stress patients, myocardial perfusion PET was superior to SPECT in image quality, interpretive certainty, and diagnostic accuracy.

Aged↗