Assessment of right ventricular function with 320-slice volume cardiac CT: comparison with cardiac magnetic resonance imaging

To evaluate the accuracy and feasibility of right ventricular function parameters measurement using 320-slice volume cardiac CT. Retrospective analysis of 50 consecutive patients (23 men, 27 women) with suspected pulmonary diseases was performed in electrocardiogram (ECG)-gated cardiac CT and cardiac magnetic resonance (CMR). Parameters including right ventricular end-diastolic volume (RVEDV), right ventricular end- systolic volume (RVESV), right ventricular stroke volume (RVSV), right ventricular cardiac output (RVCO), and right ventricular ejection fraction (RVEF) were semi-automatically and separately calculated from both CT and CMR data. Significant difference between measurements was measured by paired t test and two-variable linear regression analysis with Pearson’s correlation coefficient. Bland–Altman analysis was performed in each pair of parameters. There was little variability between the measurements by the two observers (kappa = 0.895–0.980, P < 0.05). There was good correlation between all parameters obtained by CT and CMR (P < 0.001): RVEDV (108.5 ± 21.9 ml, 113.5 ± 24.8 ml, r = 0.944), RVESV (69.8 ± 33.4 ml, 73.2 ± 35.4 ml, r = 0.972), RVSV (39.0 ± 13.2 ml, 40.2 ± 13.3 ml, r = 0.977), RVCO (2.6 ± 0.7 l, 2.6 ± 0.7 l. r = 0.958), RVEF (38.8 ± 19.1 %, 39.1 ± 19.3 %, r = 0.990), and there was no significant difference between CT and CMR measurements in RVEF (n = 50, t = ?0.677, P > 0.05). 320-slice volume cardiac CT is an accurate non-invasive technique to evaluate RV function.     

Highly accelerated cardiac MRI using iterative SENSE reconstruction: initial clinical experience

To evaluate the qualitative and quantitative performance of an accelerated cardiovascular MRI (CMR) protocol that features iterative SENSE reconstruction and spatio-temporal L₁-regularization (IS SENSE). Twenty consecutively recruited patients and 9 healthy volunteers were included. 2D steady state free precession cine images including 3-chamber, 4-chamber, and short axis slices were acquired using standard parallel imaging (GRAPPA, acceleration factor = 2), spatio-temporal undersampled TSENSE (acceleration factor = 4), and IS SENSE techniques (acceleration factor = 4). Acquisition times, quantitative cardiac functional parameters, wall motion abnormalities (WMA), and qualitative performance (scale: 1-poor to 5-excellent for overall image quality, noise, and artifact) were compared. Breath-hold times for IS SENSE (3.0 ± 0.6 s) and TSENSE (3.3 ± 0.6) were both reduced relative to GRAPPA (8.4 ± 1.7 s, p < 0.001). No difference in quantitative cardiac function was present between the three techniques (p = 0.89 for ejection fraction). GRAPPA and IS SENSE had similar image quality (4.7 ± 0.4 vs. 4.5 ± 0.6, p = 0.09) while, both techniques were superior to TSENSE (quality: 4.1 ± 0.7, p < 0.001). GRAPPA WMA agreement with IS SENSE was good (κ > 0.60, p < 0.001), while agreement with TSENSE was poor (κ < 0.40, p < 0.001). IS SENSE is a viable clinical CMR acceleration approach to reduce acquisition times while maintaining satisfactory qualitative and quantitative performance.     

Detecting cardiac involvement with magnetic resonance in patients with active eosinophilic granulomatosis with polyangiitis

Cardiac involvement is the most important prognostic factor in eosinophilic granulomatosis with polyangiitis (EGPA, Churg–Strauss syndrome). The aims of this study were to describe findings of cardiac magnetic resonance (CMR) in patients with active EGPA and to find factors associated with cardiac involvement detected by CMR that could help identify patients who would benefit from the examination. Medical records and CMR images in 16 consecutive EGPA patients (8 women and 8 men, median age of 47 years ranging from 34 to 68 years) were reviewed. Clinical features and results of laboratory tests were compared according to the presence of myocardial late gadolinium enhancement (LGE) on CMR images. The patients were followed for the development of cardiac symptoms and signs (mean follow up duration, 40.5 ± 12.8 months). Among the total of 16 patients, 8 (50 %) had myocardial LGE according to CMR, located in the subendocardial layer in 7 of them (87.5 %). The extent of LGE had a significant negative correlation with left ventricular ejection fraction (LVEF, ρ = ?0.723, p = 0.043). The presence of LGE was associated with larger end-systolic left ventricle internal dimension (34 vs. 28 mm, p = 0.027) and presence of diastolic dysfunction (75 vs. 0 %, p = 0.008) on echocardiography, elevated NT-proBNP (75 vs. 12.5 %, p = 0.012), and elevated CK-MB (62.5 vs. 0 %, p = 0.010) compared to the group without LGE. Only one patient (6.3 %) had cardiac symptoms before CMR and another patient (6.3 %) developed heart failure 4 years later during remission. The other 14 patients remained free from cardiac signs and symptoms during the follow-up period. In patients with active EGPA, CMR enables detection of cardiac involvement when cardiac symptoms are not present. Echocardiographic diastolic dysfunction and elevated NT-proBNP or CK-MB may help identify active EGPA patients who can benefit from CMR to detect cardiac involvement without cardiac symptoms.     

Lack of agreement between thermodilution and electrical velocimetry cardiac output measurements

Objective

The modified algorithm for the non-invasive determination of cardiac output (CO) by electrical bioimpedance—electrical velocimetry (EV^®)—has been reported to give reliable results in comparison with echocardiography and pulmonary arterial thermodilution (PA-TD) in patients either before or after cardiac surgery. The present study was designed to determine whether EV^®-CO measurements reflect intraindividual changes in CO during cardiac surgery.

Design

Prospective, observational study.

Setting

Operating room (OR) and intensive care unit (ICU) of a university hospital.

Patients

Twenty-nine patients undergoing elective cardiac surgery.

Interventions

None.

Measurements

CO was determined simultaneously by PA-TD and EV^® after induction of anesthesia (t1) and 4.9?±?3.5?h after ICU admission (t2).

Results

TD-CO was 3.9?±?1.4 and 5.4?±?1.1 l/min at t1 and t2 (?p?®-CO was 4.3?±?1.1 and 4.9?±?1.5 l/min at t1 and t2 (?p?=?0.013). Bland–Altman analysis showed a bias of ?0.4 l/min and 0.4 l/min and a precision of 3.2 and 3.6 l/min (34.3% and 67.4%) at t1 and t2, respectively. Analysis of the individual pre- to postoperative changes in CO with both methods revealed bidirectional changes in n?=?12 patients and unidirectional changes with a difference greater than 50% and less than 50% in n?=?9 and n?=?8 patients, respectively.

Conclusions

The disagreement between PA-TD and EV^®-CO measurements after anesthesia induction and after ICU admission, as well as the fact that thoracic bioimpedance did not adequately reflect pre- to postoperative changes in CO, questions the reliability of EV^®-CO measurements in cardiac surgery patients and contrasts sharply with previous studies.

     

Assessment of aortic stiffness among patients with systemic lupus erythematosus and rheumatoid arthritis by magnetic resonance imaging

To evaluate aortic stiffness by MRI in female patients with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA) in comparison to controls. We measured aortic strain, distensibility and pulse wave velocity (PWV) by MRI in 30 SLE patients, 31 RA patients and 53 matched controls. Mean PWV in SLE and RA patients were higher in comparison to controls (9.2 ± 4.4 vs. 7.6 ± 3.0 m/s, p = 0.04) and (6.2 ± 2.3 vs. 5.4 ± 1.7, p = 0.04) respectively. Aortic distensibility among RA patients was significantly lower in comparison to controls (4.4 ± 4.6 vs. 5.8 ± 4.9 kPa^?1 × 10^?3, p = 0.04). A significant correlation was found between PWV and age (r = 0.67, p < 0.001), Framingham risk score (r = 0.61, p < 0.001), waist to hip ratio (r = 0.45, p < 0.001), systolic blood pressure (r = 0.37, p = 0.01), diabetes (r = 0.32, p = 0.001) and dyslipidemia (r = 0.32, p = 0.001). In multivariate analysis for the prediction of PWV, variables which were found significant included: RA (p = 0.01), age (p < 0.001) and hypertension (p = 0.01) for patients with RA and SLE (p = 0.02), waist to hip ratio (p < 0.001) and total cholesterol (p < 0.001) for patients with SLE. Arterial stiffness, characterized by metrics of aortic distensibility and pulse wave velocity derived from MRI, is increased in SLE and RA female patients.     

A randomized clinical trial of ultrasound-guided infra-clavicular cannulation of the subclavian vein in cardiac surgical patients: short-axis versus long-axis approach

Purpose

The aim of this study was to compare the success rate and safety of short-axis versus long-axis approaches to ultrasound-guided subclavian vein cannulation.

Methods

A total of 190 patients requiring central venous cannulation following cardiac surgery were randomized to either short-axis or long-axis ultrasound-guided cannulation of the subclavian vein. Each cannulation was performed by anesthesiologists with at least 3 years’ experience of ultrasound-guided central vein cannulation (>150 procedures/year, 50% short-axis and 50% long-axis). Success rate, insertion time, number of needle redirections, number of separate skin or vessel punctures, rate of mechanical complications, catheter misplacements, and incidence of central line-associated bloodstream infection were documented for each procedure.

Results

The subclavian vein was successfully cannulated in all 190 patients. The mean insertion time was significantly shorter (p = 0.040) in the short-axis group (69 ± 74 s) than in the long-axis group (98 ± 103 s). The short-axis group was also associated with a higher overall success rate (96 vs. 78%, p < 0.001), first-puncture success rate (86 vs. 67%, p = 0.003), and first-puncture single-pass success rate (72 vs. 48%, p = 0.002), and with fewer needle redirections (0.39 ± 0.88 vs. 0.88 ± 1.15, p = 0.001), skin punctures (1.12 ± 0.38 vs. 1.28 ± 0.54, p = 0.019), and complications (3 vs. 13%, p = 0.028).

Conclusions

The short-axis procedure for ultrasound-guided subclavian cannulation offers advantages over the long-axis approach in cardiac surgery patients.

     

Determination of right ventricular ejection fraction by thermodilution technique — a comparison to biplane cineventriculography

Determination of right ventricular ejection fraction (RVEF) provides information about global right ventricular function, which may be important for the management of patients with various heart diseases. Right ventricular ejection fraction can be determined by new thermodilution techniques using fastresponse thermistors. To evaluate the validity of these methods, thermodilution measurements were compared with biplane cineventriculography in 22 patients undergoing cardiac catheterization. In all patients standard deviation of RVEF was below 5%. Mean RVEF, determined by thermodilution, was 52%±9%, ranging from 32% to 71% and correlated significantly with the results of angiography (RVEF: 52%±9%) (r=0.80, SEE±5%, n=22, p>0.001). Correlation was good especially in patients with small right ventricles (>60ml) (r=0.91, SEE±5%, n=13, p>0.001), lower heart rates (>65/min) (r=0.84, SEE=±6%, n=12, p>0.001) and cardiac output below 5.5 l/min (r=0.88, SEE±6%, n=11, p>0.001). Thus, if valid catheter placement is possible, right ventricular ejection fraction can be determined by thermodilution technique with good reproducibility and sufficient accuracy compared to biplane angio. Validation of this method in larger patient populations with various heart diseases is necessary.     

Muscle Relaxants as a Risk Factor for Vis-à-tergo During Penetrating Keratoplasty: A Prospective Interventional Study

Introduction

This study aimed to investigate the influence of three muscle relaxants on intraocular pressure (IOP), ocular pulse amplitude (OPA), and vis-à-tergo (VAT) in patients undergoing penetrating keratoplasty (PKP) under general anesthesia.

Methods

Ninety-five patients undergoing PKP were included in this prospective single-center interventional study. IOP and OPA were measured with a dynamic contour tonometer before and 5 min after onset of general anesthesia. Mivacurium (n = 30), atracurium (n = 35), and rocuronium (n = 30) were administered as nondepolarizing muscle relaxants. VAT was assessed 15 min after surgery had begun.

Results

When mivacurium was used, IOP decreased by 2.2 mmHg [standard deviation (SD) ±2.2 mmHg; p < 0.001]. Atracurium decreased the IOP by an average of 5.8 mmHg (SD ±1.8 mmHg; p < 0.001) and rocuronium caused an IOP reduction of 7.2 mmHg (SD ±2 mmHg; p < 0.001). The relative IOP decrease was 12% with mivacurium, 29% with atracurium, and 37% with rocuronium (p < 0.001). OPA decreased by 0.6 mmHg with mivacurium (SD ±0.6 mmHg; 26%; p < 0.001), 1.3 mmHg with atracurium (SD ±1.3 mmHg; 40%; p < 0.001), and 1.2 mmHg with rocuronium (SD ±0.7 mmHg; 42%; p < 0.001). The relative OPA decrease was 26% with mivacurium, 40% with atracurium, and 42% with rocuronium (p < 0.001). VAT occurred in 36% of cases. Mivacurium was used in 77% of these cases, atracurium in 26%, and rocuronium in 6.6% (p < 0.001).

Conclusions

Mivacurium is associated with a higher risk of VAT during PKP. Therefore, atracurium or rocuronium may minimize complications in ocular surgery with large incisions.

     

Left Atrial structure and function in hypertrophic cardiomyopathy sarcomere mutation carriers with and without left ventricular hypertrophy

Background

Impaired left atrial (LA) function is an early marker of cardiac dysfunction and predictor of adverse cardiac events. Herein, we assess LA structure and function in hypertrophy in hypertrophic cardiomyopathy (HCM) sarcomere mutation carriers with and without left ventricular hypertrophy (LVH).

Method

Seventy-three participants of the HCMNet study who underwent cardiovascular magnetic resonance (CMR) imaging were studied, including mutation carriers with overt HCM (n =?34), preclinical mutation carriers without HCM (n =?24) and healthy, familial controls (n =?15).

Results

LA volumes were similar between preclinical, control and overt HCM cohorts after covariate adjustment. However, there was evidence of impaired LA function with decreased LA total emptying function in both preclinical (64?±?8%) and overt HCM (59?±?10%), compared with controls (70?±?7%; p =?0.002 and p =?0.005, respectively). LA passive emptying function was also decreased in overt HCM (35?±?11%) compared with controls (47?±?10%; p =?0.006). Both LAtotal emptying function and LA passive emptying function were inversely correlated with the extent of late gadolinium enhancement (LGE; p?=?0.005 and p <?0.05, respectively), LV mass (p =?0.02 and p <?0.001) and interventricular septal thickness (p?<?0.001 for both) and serum NT-proBNP levels (p?<?0.001 for both).

Conclusion

LA dysfunction is detectable by CMR in preclinical HCM mutation carriers despite non-distinguishable LV wall thickness and LA volume. LA function appears most impaired in subjects with overt HCM and a greater extent of LV fibrosis.

     

Midregional pro-atrial natriuretic peptide: a novel marker of myocardial fibrosis in patients with hypertrophic cardiomyopathy

We aimed to determine the diagnostic performance of biomarkers in predicting myocardial fibrosis assessed by late gadolinium enhancement (LGE) cardiovascular magnetic resonance imaging (CMR) in patients with hypertrophic cardiomyopathy (HCM). LGE CMR was performed in 40 consecutive patients with HCM. Left and right ventricular parameters, as well as the extent of LGE were determined and correlated to the plasma levels of midregional pro-atrial natriuretic peptide (MR-proANP), midregional pro-adrenomedullin (MR-proADM), carboxy-terminal pro-endothelin-1 (CT-proET-1), carboxy-terminal pro-vasopressin (CT-proAVP), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1) and interleukin-8 (IL-8). Myocardial fibrosis was assumed positive, if CMR indicated LGE. LGE was present in 26 of 40 patients with HCM (65%) with variable extent (mean: 14%, range: 1.3–42%). The extent of LGE was positively associated with MR-proANP (r = 0.4; P = 0.01). No correlations were found between LGE and MR-proADM (r = 0.1; P = 0.5), CT-proET-1 (r = 0.07; P = 0.66), CT-proAVP (r = 0.16; P = 0.3), MMP-9 (r = 0.01; P = 0.9), TIMP-1 (r = 0.02; P = 0.85), and IL-8 (r = 0.02; P = 0.89). After adjustment for confounding factors, MR-proANP was the only independent predictor associated with the presence of LGE (P = 0.007) in multivariate analysis. The area under the ROC curve (AUC) indicated good predictive performance (AUC = 0.882) of MR-proANP with respect to LGE. The odds ratio was 1.268 (95% confidence interval 1.066–1.508). The sensitivity of MR-proANP at a cut-off value of 207 pmol/L was 69%, the specificity 94%, the positive predictive value 90% and the negative predictive value 80%. The results imply that MR-proANP serves as a novel marker of myocardial fibrosis assessed by LGE CMR in patients with HCM.     

Comparing Entropy and the Bispectral Index with the Ramsay Score in Sedated ICU Patients

Objective

ENTROPY? is a new anesthetic depth monitor based on the analysis of the EEG signal. Our aim has been to evaluate sedation of intubated surgical critically ill patients by means of the Ramsay sedation score, the Bispectral index and ENTROPY?, and to analyse the correlation between these variables.

Methods

Sedation was evaluated every 15 min for a 1 h period in 50 non-paralysed postoperative critically ill, intubated patients, enrolled over a 6 month period. A 5 min steady-state period was allowed before each assessment. Both the Bispectral index and the Entropy parameters Response Entropy (RE) and State Entropy (SE), were collected before assessing the Ramsay scale.

Results

Mean values for SE, RE and BIS were 53 ± 27, 60 ± 30, and 62 ± 24 respectively. The median value for the Ramsay was 6 (range 1–6). Significant correlation was found between the four variables (SE-BIS: r = 0.79, p < 0.001; RE-BIS: r = 0.80, p < 0.001; SE-Ramsay: ρ = ?0.71, p < 0.001, RE-Ramsay: ρ = ?0.72, p < 0.001; BIS-Ramsay: ρ = ?0.78, p < 0.001; RE-SE: r = 0.98, p < 0.001). An overlap of BIS and Entropy values for every Ramsay score value between 4–6 was found.

Conclusions

ENTROPY?, BIS and Ramsay score values correlate significantly in sedated postoperative ICU patients. ENTROPY? does not appear superior to BIS for the assessment of sedation in this context.

     

Influence of beta-blocker therapy on aortic blood flow in patients with bicuspid aortic valve

In patients with bicuspid aortic valve (BAV), beta-blockers (BB) are assumed to slow ascending aorta (AAo) dilation by reducing wall shear stress (WSS) on the aneurysmal segment. The aim of this study was to assess differences in AAo peak velocity and WSS in BAV patients with and without BB therapy. BAV patients receiving BB (BB+, n = 30, age: 47 ± 11 years) or not on BB (BB?, n = 30, age: 46 ± 13 years) and healthy controls (n = 15, age: 43 ± 11 years) underwent 4D flow MRI for the assessment of in vivo aortic 3D blood flow. Peak systolic velocities and 3D WSS were calculated at the anterior and posterior walls of the AAo. Both patient groups had higher maximum and mean WSS relative to the control group (p = 0.001 to p = 0.04). WSS was not reduced in the BB+ group compared to BB? patients in the anterior AAo (maximum: 1.49 ± 0.47 vs. 1.38 ± 0.49 N/m², p = 0.99, mean: 0.76 ± 0.2 vs. 0.74 ± 0.18 N/m², p = 1.00) or posterior AAo (maximum: 1.45 ± 0.42 vs. 1.39 ± 0.58 N/m², p = 1.00; mean: 0.65 ± 0.16 vs. 0.63 ± 0.16 N/m², p = 1.00). AAo peak velocity was elevated in patients compared to controls (p < 0.01) but similar for BB+ and BB? groups (p = 0.42). Linear models identified significant relationships between aortic stenosis severity and increased maximum WSS (β = 0.186, p = 0.007) and between diameter at the sinus of Valsalva and reduced mean WSS (β = ?0.151, p = 0.045). Peak velocity and systolic WSS were similar for BAV patients irrespective of BB therapy. Further prospective studies are needed to investigate the impact of dosage and duration of BB therapy on aortic hemodynamics and development of aortopathy.     

Left ventricular synchrony,torsion, and recoil mechanics in Ebstein’s anomaly: insights from cardiovascular magnetic resonance

Background

Disease progression and heart failure development in Ebstein’s Anomaly (EA) of the tricuspid valve is characterized by both right and left ventricular (LV) deterioration. The mechanisms underlying LV dysfunction and their role in heart failure development are incompletely understood. We hypothesized that LV dyssynchrony and impaired torsion and recoil mechanics induced by paradoxical movement of the basal septum may play a role in heart failure development.

Methods

31 EA patients and 31 matched controls underwent prospective cardiovascular magnetic resonance (CMR). CMR feature tracking (CMR-FT) was performed on apical, midventricular and basal short-axis and 4D–volume analysis was performed using three long-axis views and a short axis cine stack employing dedicated software. Circumferential uniformity ratio estimates (CURE) time-to-peak-based circumferential systolic dyssynchrony index (C-SDI), 4D volume analysis derived SDI (4D–SDI), torsion (Tor) and systolic (sysTR) and diastolic torsion rate (diasTR) were calculated for the LV. QRS duration, brain natriuretic peptide, NYHA and Total R/L-Volume Index (R/L Index) were obtained.

Results

EA patients (31.5 years; controls 31.4 years) had significantly longer QRS duration (123.35 ms?±?26.36 vs. 97.33 ms ±?11.89 p <?0.01) and showed more LV dyssynchrony (4D–SDI 7.60%?±?4.58 vs. 2.54%?±?0.62, p <?0.001; CURE 0.77?±?0.05 vs. 0.86?±?0.03, p?<?0.001; C-SDI 7.70?±?3.38 vs. 3.80?±?0.91, p =?0.001). There were significant associations of LV dyssynchrony with heart failure parameters and QRS duration. Although torsion and recoil mechanics did not differ significantly (p >?0.05) there was an association of torsion and recoil mechanics with dyssynchrony parameters CURE (sysTR r =??0.426; p =?0.017, diasTR r =?0.419; p =?0.019), 4D–SDI (sysTR r =?0.383; p =?0.044) and C-SDI (diasTR r =??0.364; p?=?0.044).

Conclusions

EA is characterized by LV intra-ventricular dyssynchrony, which is associated with heart failure and disease severity parameters. Markers of dyssynchrony can easily be quantified from CMR-FT, and may have a role in the assessment of altered cardiac function, carrying potential management implications for EA patients.

     

MRI characteristics of proctitis in Crohn’s disease on perianal MRI

Purpose

Multiple features have been described for assessing inflammation in Crohn’s disease (CD) in MR enterography, but have not been validated in perianal magnetic resonance imaging (MRI). Retrospectively, we studied which MRI features are valuable in assessing proctitis.

Materials and methods

CD patients (≥18 years) who underwent colonoscopy (reference standard) and perianal fistula MRI within 8 weeks were included. Seventeen MRI features were blindly scored by three observers and correlated to endoscopy (regression analysis). Reproducibility (multirater kappa, intraclass correlation coefficient) was determined for all three observer pairs. MRI features were considered relevant when significantly correlated to endoscopy for ≥2 observers, and reproducibility was ≥0.40 for ≥2 observer pairs.

Results

Perianal MRI of 58 CD patients were included. Wall thickness, rectal mural fat, creeping fat, and size of mesorectal lymph nodes showed a significant correlation with endoscopy for ≥2 observers (p = 0.000–0.023, p = 0.011–0.172, p = 0.007–0.011 and p = 0.000–0.005, respectively) with a kappa/intraclass correlation coefficient of ≥0.60 for ≥2 observer pairs. Perimural T2 signal and perimural enhancement significantly correlated to endoscopy (all p values ≤0.05) for all three observers and the reproducibility was ≥0.40 for ≥2 observer pairs. Mural T2 signal and degree and pattern of T1 enhancement showed significant correlation to endoscopy for two observers, but with poor to moderate reproducibility.

Conclusion

Wall thickness, mural fat, and mesorectal features (perimural T2 signal, perimural enhancement, creeping fat, and size of mesorectal lymph nodes) had significant correlation to endoscopy and were reproducible in diagnosing proctitis. Some established luminal features in MRE were considered not useful.

     

Effect of available intravenous access on accuracy and timeliness of epinephrine administration

Purpose

To evaluate the effect of available intravenous (IV) access on the accuracy and timeliness of epinephrine administration during a surprise mock severe contrast reaction.

Methods

Informed consent was waived for this prospective randomized IRB-approved study. Radiology trainees with previous annual hands-on contrast reaction training (n = 46) were randomized to one of two surprise mock contrast reactions over a 23-month period: Group 1—severe laryngeal edema with IV access present (n = 27) or Group 2—severe laryngeal edema without IV access present (n = 19). Both intramuscular (IM, Epi-Pen^®) and IV epinephrine were available in both scenarios. Time-to-treat and epinephrine administration error rates were compared by study group and by route of administration using two-tailed Student’s t test or χ ² test. Epinephrine administration errors were correlated with training experience using Pearson’s correlation.

Results

Mean time to epinephrine administration was significantly faster for scenarios without IV access (Group 2: 35 ± 16 s vs. Group 1: 62 ± 49 s, p = 0.03), and for intramuscular administrations overall (IM: 42 ± 34 s vs. IV: 98 ± 46 s, p < 0.001). Epinephrine administration errors were common: (63% [17/27, Group 1] vs. 61% [11/18, Group 2], p = 1.00), had no relationship with time to most recent hands-on training (r = 0.24, p = 0.11), and were not predicted by year of post-graduate training (r = 0.04, p = 0.79).

Conclusions

Lack of IV access is associated with a faster epinephrine administration time but no improvement in epinephrine administration error rate among radiology trainees responding to a surprise mock severe contrast reaction. Annual hands-on training appears to have little effect on epinephrine administration accuracy.

     

Zoomed echo-planar diffusion tensor imaging for MR tractography of the prostate gland neurovascular bundle without an endorectal coil: a feasibility study

Purpose

The purpose of this study was to assess the feasibility of zoomed echo-planar imaging (EPI) diffusion tensor imaging (DTI) with 2-channel parallel transmission (pTx) for MR tractography of the periprostatic neurovascular bundle (NVB) without an endorectal coil, and to compare its performance to that of conventionally acquired DTI.

Methods

8 healthy males (28.9 ± 4.6 years) underwent pelvic phased-array coil prostate MRI on a 3T system using both zoomed-EPI DTI (z-DTI) with 2-channel pTx and conventional single-shot spin-echo EPI DTI (c-DTI) acquisitions with 6 encoding directions and b-values of 0 and 1000 s/mm². Fractional anisotropy (FA) maps and tractography analysis incorporating 3D visualization of the NVB were performed from each acquisition. Fiber tract counts, estimated signal-to-noise ratio (eSNR), and image quality measures of the FA maps and NVB tractography were compared. Quantitative and image quality measures were compared using Wilcoxon signed rank tests.

Results

3 of 8 subjects had no tracts detected with c-DTI acquisition, while all 8 had tracts detected with z-DTI. z-DTI acquisition yielded significantly more fiber tracts (c-DTI: 77 ± 116 tracts; z-DTI: 430 ± 228 tracts; p = 0.019) and higher eSNR (c-DTI: 2.9 ± 1.2; z-DTI: 13.17 ± 9.9; p = 0.014). Relative to c-DTI acquisitions, z-DTI FA maps showed significantly reduced artifact (p = 0.008) and reduced anatomic distortion of the prostate (p = 0.010), while z-DTI tractography showed significantly better overall visual quality (p = 0.011), tract symmetry (p = 0.010), tract coherence (p = 0.011), and subjective similarity to the actual NVB (p = 0.011).

Conclusion

Zoomed-EPI DTI acquisition for tractography of the prostate gland NVB improves quantitative and qualitative measures of image and tract fiber quality, allowing tractography of the NVB at 3T without using an endorectal coil.

     

Comparison of quantitative imaging parameters using cardiovascular magnetic resonance between cardiac amyloidosis and hypertrophic cardiomyopathy: inversion time scout versus T1 mapping

To compare inversion time (TI) parameters, native T1, and extracellular volume (ECV) on cardiac magnetic resonance (CMR) imaging between patients with cardiac amyloidosis (CA) or hypertrophic cardiomyopathy (HCMP). Forty six patients with biopsy-confirmed CA and 30 patients with HCMP who underwent CMR were included. T1 and TI values were measured in the septum and cavity of the left ventricle on T1 mapping and TI scout images. TI values were selected at nulling point for each myocardium and blood pool. Native T1, ECV, and TI interval values were significantly different between the CA (1170.5?±?86.4 ms, 56.7?±?12.2, ? 11.5?±?28.4 ms) and HCMP (1059.5?±?63.4 ms, 28.5?±?5.8, 66.2?±?25.4 ms) (all p?<?0.001). The diagnostic performance of the TI interval (area under the ROC curve, 0.975) was not inferior to that of the ECV (0.980, p?=?0.776), and it was superior to that of the native T1 (0.845, p?=?0.004). The diagnostic performance of TI interval was comparable to that of ECV for differential diagnosis between CA and HCMP. TI interval showed the feasibility as quantitative CMR parameter when T1 mapping images are not available.     

Relationship of basal-septal fibrosis with LV outflow tract obstruction in hypertrophic cardiomyopathy: insights from cardiac magnetic resonance analysis

Myocardial fibrosis is frequently observed and may be associated with the prognosis in patients with hypertrophic cardiomyopathy (HCM); however, the clinical pathophysiological features, particularly in terms of fibrosis, of hypertrophic obstructive cardiomyopathy (HOCM) remain unclear. This study aimed to determine a role of local fibrosis in HOCM using cardiac magnetic resonance (CMR). 108 consecutive HCM patients underwent CMR. HOCM was defined as a left ventricular outflow tract (LVOT) pressure gradient ≥30 mmHg at rest. Myocardial mass and fibrosis mass by late gadolinium-enhancement CMR (LGE-CMR) were calculated and the distribution/pattern was analyzed using the AHA 17-segment model. LV ejection fraction (LVEF) was significantly higher in patients with HOCM (n = 19) than in those with nonobstructive HCM (n = 89) (P < 0.05). Both total myocardial and fibrosis masses in LV were similar in the two groups (P = 0.385 and P = 0.859, respectively). However, fibrosis in the basal septum was significantly less frequent in the HOCM group than in the nonobstructive HCM group (P < 0.01). The LVOT pressure gradient was significantly higher in the basal-septal non-fibrosis group than in the fibrosis group (23.6 ± 37.3 vs. 4.8 ± 11.4 mmHg, P < 0.01). Multivariate analysis revealed that basal-septal fibrosis was an independent negative predictor of LVOT obstruction in addition to the local wall thickness and LVEF as positive predictors in HCM patients. In conclusion, a significant association was observed between LVOT obstruction and basal septal fibrosis by LGE-CMR in HCM patients. In addition to negative impact of basal-septal fibrosis, basal-septal hypertrophy and preserved global LV contractility may be associated with the pathophysiological features of LVOT obstruction.     

Quantification of stenotic mitral valve area and diagnostic accuracy of mitral stenosis by dual-source computed tomography in patients with atrial fibrillation: comparison with cardiovascular magnetic resonance and transthoracic echocardiography

This study aimed to evaluate the utility of dual-source computed tomography (DSCT) for quantification of the mitral valve area (MVA) in patients with atrial fibrillation (AF) and mitral stenosis (MS) and to compare the results of DSCT with those of cardiovascular magnetic resonance (CMR) and transthoracic echocardiography (TTE). One hundred-two patients with AF and MS who had undergone electrocardiography-gated DSCT, TTE and CMR prior to operation were retrospectively enrolled. The MVA was planimetrically determined by DSCT, CMR, and TTE, as well as by Doppler TTE using the pressure half-time method (TTE–PHT). Agreement, relationship between measurements, and the highest accuracy were evaluated using Bland–Altman, Pearson correlation, and receiver operating characteristic analyses. The MVA on DSCT (mean, 1.27 ± 0.27 cm²) was significantly larger than that on CMR (1.15 ± 0.28 cm², P < 0.05), TTE-planimetry and TTE–PHT (1.16 ± 0.28 and 1.07 ± 0.30 cm², respectively; P < 0.05). TTE-planimetry had better correlation with planimetry on DSCT and CMR (r = 0.65 and 0.67, respectively; P < 0.05) than TTE–PHT (r = 0.51 and 0.55, respectively; P < 0.05). Using an MVA of 1.0 cm² on TTE-planimetry and TTE–PHT as the reference, the optimal thresholds for detecting severe MS on DSCT was 1.19 cm². The planimetry of the MVA measured by DSCT may be a reliable, alternative method for the quantification of MS in patients with AF.     

Influence of microvascular dysfunction on regional myocardial deformation post-acute myocardial infarction: insights from a novel angiographic index for assessing myocardial tissue-level reperfusion

To investigate the impact of microvascular dysfunction assessed by angiography on myocardial deformation assessed by two-dimensional speckle-tracking echocardiography in ST-segment elevation myocardial infarction (STEMI). A total of 121 STEMI patients who received primary percutaneous coronary intervention were included. Thrombolysis in myocardial infarction, Myocardial Perfusion Frame Count (TMPFC), a novel angiographic method to assess myocardial perfusion, was used to evaluate microvascular dysfunction. Two-dimensional speckle-tracking echocardiography was performed at 3–7 days after reperfusion. The infarction related regional longitudinal (RLS) strains as well as circumferential (RCS) and radial (RRS) ones, along with global longitudinal, circumferential (GCS), and radial (GRS) strains were measured. Patients with microvascular dysfunction had decreased peak amplitude of RLS (p = 0.012), RCS (p < 0.001), RRS (p = 0.012) at the regional level and decreased peak amplitude of GCS (p = 0.005), GRS (p = 0.012) at the global level. The RCS to RLS and RCS to RRS ratios were significantly different between patients without than with microvascular dysfunction (1.28 ± 0.31 vs. 1.07 ± 0.47, p = 0.027 and 0.69 ± 0.33 vs. 0.56 ± 0.28, p = 0.047). Receiver operator characteristics curves identified a cutoff value of 94 frames for TMPFC to differentiate between normal and abnormal wall motion score index in the sub-acute phase of STEMI (AUC = 0.72; p < 0.001). In the sub-acute phase of STEMI, the presence of microvascular dysfunction in infarcted tissue relates to reduced global and regional myocardial deformation. RCS alterations were more significant than RLS and RRS between patients with than without microvascular dysfunction. TMPFC was useful to predict left ventricular systolic dysfunction in the sub-acute phase of STEMI.