Anatomic Considerations for Injection of the Lateral Atlanto-Axial Joint.

OBJECTIVE: We aimed to define the potential complications of intra-articular steroid injections into the lateral C1-2 articulations and safety margins to the relevant structures. METHODS: A total of 488 contrast-enhanced computed tomography angiogram (CTA) "arch to vertex" studies were retrospectively reviewed for theoretical intersection of the vertebral artery or thecal sac and distance of the named structures from the anticipated/theoretical trajectory of injection into the lateral C1-C2 joint. RESULTS: Patients were 60.4±15.8 years old and 55.5% male. In total, seven vertebral arteries and 11 thecal sac theoretical intersections were found. In cases without a direct intersection, the distance from the trajectory (range) was 0.71±0.18 (0.22-1.44) cm to the vertebral artery and 0.6±0.22 (0.14-1.8) cm to the thecal sac. CONCLUSIONS: Although injection of steroid into the lateral C1-C2 articulation for pain management has historically been reported to carry risk of severe complications due to close proximity and location variability of surrounding structures, our study quantifies the potential risk of such injections. Further, our analysis suggests that preprocedural imaging should be considered.

Ultrasound assessment of the posterolateral elbow ulnohumeral gap in normal subjects with and without posterolateral drawer testing.

Background: Posterolateral rotator instability (PLRI) is the most common pattern of recurrent elbow instability, and current imaging to aid PLRI diagnosis is limited. Thus, we sought to define use of ultrasound (US) to determine normal lateral ulnohumeral joint measurements, with and without posterolateral drawer testing to provide an insight into how US may aid diagnosis. Methods: Sixty elbows were evaluated in thirty healthy volunteers. The lateral ulnohumeral gap (LUHG) was measured with US in the resting position while the posterolateral drawer stress test maneuver was applied. Joint laxity was calculated as the difference between maximum stress and average rest measurements. Two independent readers assessed each elbow with comparison performed between stress and rest positions. Results: Differences in the LUHG were evident between stress and rest conditions (reader 1: P < .0001 and reader 2: P = .0002). At rest, median LUHG values were 2.31 mm and 2.05 mm for readers 1 and 2 respectively, while at stress 2.88 mm and 2.9 mm for readers 1 and 2. Median joint laxity was 0.8 mm for reader 1 and 1.1 mm for reader 2. Pearson correlation was r = 0.457 (absolute intraclass correlation coefficient [ICC] = 0.608) while under stress and r = 0.308 (absolute intraclass correlation coefficient [ICC] = 0.417) at rest. Median joint laxity demonstrated a Pearson correlation of r = 0.161 and absolute intraclass correlation coefficient [ICC] = 0.252. Conclusions: This study demonstrates a dynamic US assessment for PLRI, which aimed to assess the usefulness and feasibility of a laxity measurement after the application of a posterolateral drawer stress maneuver in a healthy population. Although establishing concordance between readers in measuring an LUHG under stress, the utility of a laxity measurement alone is not clear as correlation of measurements is not excellent; hence, an upper limit of normal for the ulnohumeral gap under stress may be more useful. Further evaluation of this technique is required in patients with PLRI.

Transcatheter Aortic and Mitral Valve Replacements.

Amid rapid growth in transcatheter valvular interventions computed tomography (CT) has emerged as a pivotal noninvasive imaging resource that can be used throughout many stages of the transcatheter heart valve process, enhancing procedural success and efficacy. It affords a three-dimensional assessment of the aortic and challenging saddle-shaped mitral annulus, facilitating appropriate device selection, sizing, and preprocedural prediction angles for prosthetic deployment. Postprocedural imaging allows documentation of procedural success, evaluation of prosthesis positioning, and identifying asymptomatic complications. This article provides an overview of the role of CT in both trancatheter aortic valve repair (TAVR) and transcatheter mitral valve replacement (TMVR).

Prognosis of CT-derived Fractional Flow Reserve in the Prediction of Clinical Outcomes.

PURPOSE: To examine the prognostic implication of fractional flow reserve (FFR) derived from coronary CT (FFRCT) in routine clinical practice. MATERIALS AND METHODS: Patients referred for FFRCT analysis at a single center between October 2015 and June 2017 were retrospectively included and followed up for rates of invasive angiography and clinical events. Two hundred seven patients underwent successful FFRCT analysis with seven lost to follow-up, leaving 200 (mean age ± standard deviation, 62.4 years ± 10.0; 49 [24.5%] women) patients for analysis. At coronary CT angiography, patients were categorized as having significant stenosis (SS) in the presence of a diameter stenosis greater than or equal to 50% (hereafter, SS positive) and flow limitation in the presence of a postlesion (that is, FFRCT measured 2 cm to the distal aspect of the lesion) FFRCT less than 0.80 (hereafter, FFRCT positive). Vessel-oriented clinical events (VOCEs) were defined as vessel-related late revascularization (>90 days), myocardial infarction, and cardiac mortality. RESULTS: At CT angiography, 130 (65%) studies were SS positive and 63 (31.5%) were FFRCT positive. At median follow-up of 477 days (range, 252-859 days), there were 26 VOCE end points in 22 patients: 22 revascularizations and four nonfatal myocardial infarctions. VOCE end points occurred in zero of 58 (0%) of SS-negative and FFRCT negative patients, in eight of 79 (10.1%) of SS-positive and FFRCT-negative patients, in zero of 12 (0%) of SS-negative and FFRCT-positive patients, and in 18 of 51 (35.3%) of SS-positive and FFRCT-positive patients (log-rank χ2 = 30.1; P < .001). At multivariable Cox regression, both FFRCT (hazard ratio per 0.1 decrease, 1.54 [95% confidence interval: 1.1, 2.2] P = .013) and stenosis (hazard ratio per unit increase, 2.16 [95% confidence interval: 1.25, 3.72] P = .006) were independently associated with VOCE. CONCLUSION: Stenosis and FFRCT are independent predictors of intermediate-term outcomes. In the absence of a stenosis greater than 50%, a positive FFRCT result is not associated with an increased intermediate risk.© RSNA, 2019Supplemental material is available for this article.See also commentary by Fairbairn and Bull in this issue.

Hypertrophic Cardiomyopathy (HCM): New insights into Coronary artery remodelling and ischemia from FFRCT.

INTRODUCTION: Angina, myocardial ischemia, and coronary artery physiology in hypertrophic cardiomyopathy (HCM) are poorly understood. However, coronary computed tomography angiography (CCTA) with fractional flow reserve from CT (FFRCT) analysis offers a non-invasive method for evaluation of coronary artery volume to myocardial mass ratio (V/M) that may provide insight into such mechanisms. Thus, we sought to investigate changes in V/M in HCM. METHODS: A retrospective analysis was performed on 37 HCM patients and 37 controls matched for age, sex, and cardiovascular risk factors; CCTA-derived coronary artery lumen volume (V) and myocardial mass (M) were used to determine V/M. FFRCT values were calculated for the left anterior descending (LAD), left circumflex (LCx) and right coronary (RCA) arteries as well as the 3-vessel cumulative FFRCT values. RESULTS: HCM patients had significantly increased myocardial mass (176 ±â€¯84 vs. 119 ±â€¯27 g, p < 0.0001) and total coronary artery luminal volume (4112 ±â€¯1139 vs. 3290 ±â€¯924 mm3, p < 0.0001) that resulted from increases in segmented luminal volumes of both the left and right coronary artery systems. However, HCM patients had significantly decreased V/M (23.8 ±â€¯5.9 vs. 26.5 ±â€¯5.3 mm3/g; p = 0.026) which was further decreased when restricting V/M analysis to those HCM patients with septal hypertrophy (22.4 mm3/g, p = 0.01) that was mild-moderately predictive of HCM (AUC = 0.68). HCM patients also showed significantly lower nadir FFRCT values in the LCx (0.87 ±â€¯0.06 vs. 0.91 ±â€¯0.06, p = 0.02), and cumulative 3-vessel FFRCT values (2.58 ±â€¯0.18 vs. 2.63 ±â€¯0.14, p = 0.006). CONCLUSIONS: HCM patients demonstrate significantly greater coronary volume. Despite this, HCM patients suffer from decreased V/M. Further prospective studies evaluating the relationship between V/M, angina, and heart failure in HCM are needed.