Factors Affecting Image Resolution in a Modern Angiographic Suite: A Phantom-Based Study.

BACKGROUND: Improvements in angiographic imaging systems technology provide options to decrease radiation exposure. The effect of these variations on image resolution is unknown. METHODS: Using an American National Standards Institution phantom, a high-contrast (line-pair) and low contrast (Gammex 151) phantoms, 5 second images were acquired using a Phillips Allure angiographic suite, using fluoroscopic capture (FC) as well as cineangiography (CA) in posterior anterior (PA) and left anterior oblique (LAO) projections as well as high and low table positions. Image resolutions were measured as ranked by three independent trained observers blinded to the purpose of the assessments. Comparative analyses were performed. Interobserver agreement was evaluated. RESULTS: High contrast image resolution was significantly lower with FC compared to CA (median [interquartile range], 1.69 [1.52-1.69] mm, vs 2.09 [1.88-2.09] mm, P < 0.001). No significant differences were observed in between PA and LAO projections as well as low and high table positions. Low contrast resolution was also lower with FC compared to CA (5 [6.5-5] vs 3 [5-3] mm, P < 0.001). No significant differences in high-contrast or low-contrast resolution were noted between PA and LAO projections, or high and low table positions. Both low and high-contrast image resolution improved with higher radiation exposure. Good interobserver agreement was noted (Fleiss-Kappa ranging from 0.69-0.74). CONCLUSION: Image resolution was perceived to be better with CA compared to FC, although not significantly affected by beam angulation or table height. Aligning resolution needs with imaging modality and maximizing table height may improve procedural efficacy and safety.

Comparison of Diagnostic Accuracy of Digital Plethysmography Versus Duplex Ultrasound in Detecting Radial Artery Occlusion After Transradial Access.

BACKGROUND: Duplex Doppler ultrasonography (USG) remains the gold standard for evaluation of radial artery occlusion (RAO) after transradial access (TRA). The diagnostic accuracy of digital plethysmography, which is cheaper and widely available, for evaluation of RAO after TRA is not known. METHODS: Patients undergoing TRA were prospectively studied. After undergoing TRA for diagnostic or interventional coronary procedure and obtaining radial artery hemostasis, the radial artery was evaluated for presence or absence of RAO using digital plethysmography of the ipsilateral index finger and the thumb using modified reverse Barbeau's test (MRBT) and USG. Sensitivity, specificity, predictive values, likelihood ratios and other metrics of evaluation of diagnostic performance of MRBT in reference to USG, the current gold standard, were evaluated. RESULTS: 503 patients who underwent TRA for coronary procedures were studied. MRBT demonstrated a sensitivity = 96.2%, specificity = 99.8%, positive predictive value = 96.1, negative predictive value = 99.8, likelihood ratio (+) = 481, likelihood ratio (-) = 0.38, diagnostic accuracy = 99.6, diagnostic odds ratio = 11,904, Youden's index = 0.96, receiver operator characteristic derived c-statistic = 0.98 and Cohen's k = 0.98 when compared to USG. MRBT performed using the ipsilateral index finger and the thumb was no different. Agreement between absence of ipsilateral radial artery pulsation and RAO was weak (Cohen's k = 0.69). CONCLUSIONS: MRBT using ipsilateral digital plethysmography performs comparably to USG for assessment of presence of RAO after TRA. There is no significant difference between MRBT performed using the ipsilateral thumb or the index finger.

Variability of forearm collateral circulation: An observational study of serial hand plethysmography testing.

OBJECTIVES: Evaluation of plethysmography as a reliable triage tool to access collateral circulation in the hand prior to transradial access. BACKGROUND: Hand plethysmographic testing has been used for access site triage prior to cardiac catheterization despite a lack of data supporting its result's stability. METHODS: Cohort of consecutive outpatients presenting for evaluation prior to cardiac catheterization underwent hand plethysmographic testing at the beginning of the office visit and before discharge. Demographics and clinical data was recorded. RESULTS: Hands (N = 887) in 445 patients were evaluated using the Barbeau plethysmography technique. Barbeau Test (BT) patterns A, B, C, and D were observed in 58%, 30%, 8% and 4% on initial evaluation. On preliminary evaluation, 780 (88%) hands had a "low-risk" pattern (A or B) and 107 (12%) hands had a "high-risk" pattern (C or D). Repeat evaluation performed 50 ±â€¯26 min later revealed a 'low-risk' pattern in 809 (91%) hands with 78 (9%) of hands showing a persistent "high risk" pattern. In 29 (27%) high-risk hands, spontaneous conversion to pattern B within <1 h occurred. Reverse Barbeau Test (RBT) at baseline showed pattern A, B, C and D in 95.9%, 2.8%, 1% and .4% respectively. There was no significant change in RBT upon follow-up evaluation. Strength of the radial artery pulsation was significantly associated with the pattern of RBT and the strength of ulnar pulsation was associated with the results of the BT. CONCLUSIONS: Plethysmographic testing of forearm circulation demonstrates variability over short intervals suggesting poor reliability for access site triage.