Evaluation of right ventricular volume and ejection fraction by gated 18F-FDG PET in patients with pulmonary hypertension: Comparison with cardiac MRI and CT

Background

Right ventricular (RV) function is a powerful predictor of survival in patients with pulmonary hypertension (PH), but noninvasively assessing RV function remains a challenge. The aim of this study was to prospectively compare gated ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) myocardial imaging (gated PET), cardiac magnetic resonance (CMR), and cardiac computed tomography (CCT) for the assessment of RV volume and ejection fraction in patients with PH.

Methods

Twenty-three consecutive patients aged more than 16 years diagnosed with PH were included. All patients underwent gated PET, CMR, and CCT within 7 days. Right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume (RVESV), and right ventricular ejection fraction (RVEF) were calculated by three imaging modalities. RV ¹⁸F-FDG uptake was determined as RV-corrected standardized uptake value (SUV), and the ratio of RV to left ventricular (LV)-corrected SUV (Corrected SUV R/L).

Results

Gated PET showed a moderate correlation (r = 0.680, P < .001) for RVEDV, good correlation for RVESV (r = 0.757, P < .001) and RVEF (r = 0.788, P < .001) with CMR, and good correlation for RVEDV (r = 0.767, P < .001), RVESV (r = 0.837, P < .001), and RVEF (r = 0.730, P < .001) with CCT. Bland-Altman analysis revealed systematic underestimation of RVEDV and RVESV and overestimation of RVEF with gated PET compared with CMR and CCT. The correlation between RVESV (r = 0.863, P < .001), RVESV (r = 0.903, P < .001), and RVEF (r = 0.853, P < .001) of CMR and those of CCT was excellent; Bland-Altman analysis showed only a slight systematic variation between CMR and CCT. There were statistically significant negative correlations between RV-corrected SUV and RVEF-CMR (r = ?0.543, P < .01), Corrected SUV R/L and RVEF-CMR (r = ?0.521, P < .05), RV-corrected SUV and RVEF-CCT (r = ?0.429, P < .05), Corrected SUV R/L and RVEF-CCT (r = ?0.580, P < .01), respectively.

Conclusion

Gated PET had moderate-to-high correlation with CMR and CCT in the assessments of RV volume and ejection fraction. It is an available method for simultaneous assessing of RV function and myocardial glucose metabolism in patients with PH.     

Quantitative analysis of left ventricular dyssynchrony using cardiac computed tomography versus three-dimensional echocardiography

Objectives

We investigated whether cardiac computed tomography (CCT) can determine intraventricular dyssynchrony in comparison to real-time three-dimensional echocardiography (RT3DE) in patients who are considered for cardiac resynchronisation therapy (CRT).

Methods

35 patients considered for CRT were examined. Left ventricular (LV) dyssynchrony was quantified by calculating the standard deviation index (SDI) of 17 myocardial LV segments by RT3DE and ECG-gated contrast-enhanced 64-slice dual-source CCT. For both analyses the same software algorithm (4D LV-Analysis) was used.

Results

Close correlations were observed for end-systolic volume, end-diastolic volume and LV ejection fraction between the two techniques (r?=?0.94, r?=?0.92 and r?=?0.95, respectively, P?P?P?P?P?Conclusion Quantitative assessment of LV dyssynchrony is feasible by CCT. Owing to its higher reproducibility and faster analysis time compared with RT3DE, this technique may represent a valuable alternative for dyssynchrony assessment.

Key Points

? Quantitative assessment of left ventricular dyssynchrony is feasible by cardiac computed tomography (CCT). ? This technique has been compared with real-time three-dimensional echocardiography (RT3DE). ? Reproducibility is significantly higher for CCT compared with RT3DE. ? Time spent for analysis is significantly shorter for CCT. ? Computed tomography may represent a valuable alternative to ultrasound for dyssynchrony assessment.     

Cardiovascular magnetic resonance imaging assessment of diastolic dysfunction in a population without heart disease: a gender-based study

Objectives

Asymptomatic left ventricular (LV) diastolic dysfunction is increasingly recognised as an important diagnosis. Our goal was to study the prevalence and gender differences in subclinical LV diastolic dysfunction, using cardiovascular magnetic resonance imaging (CMR) at 3 T.

Methods

We prospectively studied 48 volunteers (19 male and 29 female, mean age 49?±?7 years) with no evidence of cardiovascular disease. We used CMR to measure left atrium (LA) and LV volumes, LV peak filling rate and transmitral flow.

Results

The overall prevalence of LV diastolic dysfunction in our cohort varied between 20 % (based on evaluation of LV filing profiles) and 24 % (based on the evaluation of the transmitral flow). The prevalence of diastolic dysfunction was higher in men than in women, independently of the criteria used (P between 0.004 and 0.022). Indexed LV end-diastolic volume, indexed LV stroke volume, indexed LV mass, indexed LA minimum volume and indexed LA maximum volume were significantly greater in men than in women (P?<?0.05). All the subjects had LV ejection fractions within the normal range.

Conclusions

It is clinically feasible to study diastolic flow and LV filling with CMR. CMR detected diastolic dysfunction in asymptomatic men and women.

Key Points

? CMR imaging offers new possibilities in assessing left ventricular diastolic function. ? The prevalence of diastolic dysfunction is higher in men than in women. ? The prevalence of some diastolic dysfunction in a normal population is 24 %.     

Attenuated right ventricular energetics evaluated using 11C-acetate PET in patients with pulmonary hypertension

Purpose

The right ventricle (RV) has a high capacity to adapt to pressure or volume overload before failing. However, the mechanisms of RV adaptation, in particular RV energetics, in patients with pulmonary hypertension (PH) are still not well understood. We aimed to evaluate RV energetics including RV oxidative metabolism, power and efficiency to adapt to increasing pressure overload in patients with PH using ¹¹C-acetate PET.

Methods

In this prospective study, 27 patients with WHO functional class II/III PH (mean pulmonary arterial pressure 39.8?±?13.5 mmHg) and 9 healthy individuals underwent ¹¹C-acetate PET. ¹¹C-acetate PET was used to simultaneously measure oxidative metabolism (k _mono) for the left ventricle (LV) and RV. LV and RV efficiency were also calculated.

Results

The RV ejection fraction in PH patients was lower than in controls (p?=?0.0054). There was no statistically significant difference in LV k _mono (p?=?0.09). In contrast, PH patients showed higher RV k _mono than did controls (0.050?±?0.009 min^?1 vs. 0.030?±?0.006 min^?1, p?<?0.0001). PH patients exhibited significantly increased RV power (p?<?0.001) and hence increased RV efficiency compared to controls (0.40?±?0.14 vs. 0.017?±?0.12 mmHg·mL·min/g, p?=?0.001).

Conclusion

The RV oxidative metabolic rate was increased in patients with PH. Patients with WHO functional class II/III PH also had increased RV power and efficiency. These findings may indicate a myocardial energetics adaptation response to increasing pulmonary arterial pressure.     

Partial splenic embolisation using n-butyl cyanoacrylate: intraprocedural evaluation by magnetic resonance imaging

Objectives

To evaluate the use of diffusion-weighted imaging (DWI) for estimating infarcted splenic volume during partial splenic embolisation (PSE) using n-butyl cyanoacrylate (NBCA).

Methods

Twenty consecutive patients (57.2?±?11.7 years) with hypersplenism underwent PSE. Intrasplenic branches were embolised using NBCA via a 2.1-French microcatheter aiming at infarction of 50 to 80 % of total splenic volume. Immediately after PSE, signal intensities (SI) of embolised and non-embolised splenic parenchyma were measured on DWI. Semi-automated volumetry (SAV) on DWI was compared with conventional manual volumetry (MV) on contrast-enhanced CT 1 week after PSE. Platelet counts were recorded before and after PSE.

Results

The SI on DWI in the embolised parenchyma decreased significantly (P?<?0.01) to 24.7?±?8.1 % as compared to non-embolised parenchyma. SAV and MV showed a strong correlation (r?=?0.913 before PSE, r?=?0.935 after PSE, P?<?0.01) and significant (P?<?0.01) reduction of normal splenic volume was demonstrated on both SAV (71.9?±?12.4 %) and MV (73.6?±?9.3 %) after PSE. Based on the initial SAV, three patients (15 %) underwent additional branch embolisation to reach sufficient infarction volume. Platelet counts elevated significantly (522.8?±?209.1 %, P?<?0.01) by 2 weeks after PSE. No serious complication was observed.

Conclusion

Immediate SI changes on DWI after PSE allowed semi-automated splenic volumetry on site.

Key Points

? Partial splenic embolisation (PSE) is an important interventional technique for hypersplenism ? Diffusion-weighted MR reveals an immediate decrease in signal in the embolised parenchyma ? Such signal reduction permits semi-automated splenic volumetry on site. ? This allows precise quantification of the amount of parenchyma infarcted, avoiding additional PSE.     

Cardiac magnetic resonance before and after percutaneous pulmonary valve implantation

Purpose

To measure the magnetic resonance (MR) artefact produced by a percutaneous pulmonary valve stent and to evaluate the changes in volumetric and functional right ventricle (RV) parameters due to percutaneous pulmonary valve implantation (PPVI).

Materials and methods

A Melody valve was studied in vitro using clinical cardiac MR (CMR) sequences. In vivo, we analysed the CMR examinations obtained before and after PPVI of 27 consecutive patients. The echocardiography pressure gradient (PG) and catheter PG were measured. The Wilcoxon test was used for comparisons.

Results

In vitro, the least difference between artefact extent and actual valve size (0.1 mm) was obtained with a steady-state free precession (SSFP) sequence. In vivo, RV end-diastolic volume (ml/m²), end-systolic volume (ml/m²) and ejection fraction (%) were 79 ± 42, 43 ± 41 and 49 ± 13 before PPVI and 64 ± 21 (p = 0.054), 30 ± 14 (p = 0.021), and 54 ± 12 (p = 0.018) 6 months after PPVI, respectively. The PG and regurgitation fraction (RF) were 36 ± 15 mmHg and 14 ± 18 % before PPVI and 13 ± 15 mmHg (p < 0.001) and 2 ± 5 % (p = 0.013) after PPVI, respectively. No significant differences were found comparing the PG measured with CMR, echocardiography and catheter.

Conclusions

We showed in vitro that the SSFP sequence produced the most accurate valve measurement. After PPVI, CMR showed a strong decrease of PG and RF with a significant improvement of RV function.     

Left and right ventricle assessment with Cardiac CT: validation study vs. Cardiac MR

Objectives

To compare Magnetic Resonance (MR) and Computed Tomography (CT) for the assessment of left (LV) and right (RV) ventricular functional parameters.

Methods

Seventy nine patients underwent both Cardiac CT and Cardiac MR. Images were acquired using short axis (SAX) reconstructions for CT and 2D cine b-SSFP (balanced-steady state free precession) SAX sequence for MR, and evaluated using dedicated software.

Results

CT and MR images showed good agreement: LV EF (Ejection Fraction) (52?±?14% for CT vs. 52?±?14% for MR; r?=?0.73; p?>?0.05); RV EF (47?±?12% for CT vs. 47?±?12% for MR; r?=?0.74; p?>?0.05); LV EDV (End Diastolic Volume) (74?±?21?ml/m2 for CT vs. 76?±?25?ml/m2 for MR; r?=?0.59; p?>?0.05); RV EDV (84?±?25?ml/m2 for CT vs. 80?±?23?ml/m2 for MR; r?=?0.58; p?>?0.05); LV ESV (End Systolic Volume)(37?±?19?ml/m2 for CT vs. 38?±?23?ml/m2 for MR; r?=?0.76; p?>?0.05); RV ESV (46?±?21?ml/m2 for CT vs. 43?±?18?ml/m2 for MR; r?=?0.70; p?>?0.05). Intra- and inter-observer variability were good, and the performance of CT was maintained for different EF subgroups.

Conclusions

Cardiac CT provides accurate and reproducible LV and RV volume parameters compared with MR, and can be considered as a reliable alternative for patients who are not suitable to undergo MR.

Key Points

? Cardiac-CT is able to provide Left and Right Ventricular function. ? Cardiac-CT is accurate as MR for LV and RV volume assessment. ? Cardiac-CT can provide accurate evaluation of coronary arteries and LV and RV function.     

Salvage assessment with cardiac MRI following acute myocardial infarction underestimates potential for recovery of systolic strain

Objectives

Our aim was to evaluate the relationship between the degree of salvage following acute ST elevation myocardial infarction (STEMI) and subsequent reversible contractile dysfunction using cardiac magnetic resonance (CMR) imaging.

Methods

Thirty-four patients underwent CMR examination 1–7 days after primary percutaneous coronary intervention (PPCI) for acute STEMI with follow-up at 1 year. The ischaemic area-at-risk (AAR) was assessed with T2-weighted imaging and myocardial necrosis with late gadolinium enhancement. Myocardial strain was quantified with complementary spatial modulation of magnetisation (CSPAMM) tagging.

Results

Ischaemic segments with poor (<25 %) or intermediate (26–50 %) salvage index were associated with worse Eulerian circumferential (Ecc) strain immediately post-PPCI (?9.1 %?±?0.6, P?=?0.033 and ?11.8 %?±?1.3, P?=?0.003, respectively) than those with a high (51–100 %) salvage index (?14.4 %?±?1.3). Mean strain in ischaemic myocardium improved between baseline and follow-up (?10.1 %?±?0.5 vs. ?16.2 %?±?0.5 %, P?<?0.0001). Segments with poor salvage also showed an improvement in strain by 1 year (?9.1 %?±?0.6 vs. ?15.3 %?±?0.6, P?=?0.033) although they remained the most functionally impaired.

Conclusions

Partial recovery of peak systolic strain following PPCI is observed even when apparent salvage is less than 25 %. Late gadolinium enhancement (LGE) may not equate to irreversibly injured myocardium and salvage assessment performed within the first week of revascularisation may underestimate the potential for functional recovery.

Key Points

? MRI can measure how much myocardium is damaged after a heart attack. ? Heart muscle that appears initially non-viable may sometimes partially recover. ? Enhancement around the edges of infarcts may resolve over time. ? Evaluating new cardio-protective treatments with MRI requires appreciation of its limitations.     

Diagnostic accuracy of 128-slice dual-source CT coronary angiography: a randomized comparison of different acquisition protocols

Objectives

To compare the diagnostic performance and radiation exposure of 128-slice dual-source CT coronary angiography (CTCA) protocols to detect coronary stenosis with more than 50 % lumen obstruction.

Methods

We prospectively included 459 symptomatic patients referred for CTCA. Patients were randomized between high-pitch spiral vs. narrow-window sequential CTCA protocols (heart rate below 65 bpm, group A), or between wide-window sequential vs. retrospective spiral protocols (heart rate above 65 bpm, group B). Diagnostic performance of CTCA was compared with quantitative coronary angiography in 267 patients.

Results

In group A (231 patients, 146 men, mean heart rate 58?±?7 bpm), high-pitch spiral CTCA yielded a lower per-segment sensitivity compared to sequential CTCA (89 % vs. 97 %, P?=?0.01). Specificity, PPV and NPV were comparable (95 %, 62 %, 99 % vs. 96 %, 73 %, 100 %, P?>?0.05) but radiation dose was lower (1.16?±?0.60 vs. 3.82?±?1.65 mSv, P?<?0.001). In group B (228 patients, 132 men, mean heart rate 75?±?11 bpm), per-segment sensitivity, specificity, PPV and NPV were comparable (94 %, 95 %, 67 %, 99 % vs. 92 %, 95 %, 66 %, 99 %, P?>?0.05). Radiation dose of sequential CTCA was lower compared to retrospective CTCA (6.12?±?2.58 vs. 8.13?±?4.52 mSv, P?<?0.001). Diagnostic performance was comparable in both groups.

Conclusion

Sequential CTCA should be used in patients with regular heart rates using 128-slice dual-source CT, providing optimal diagnostic accuracy with as low as reasonably achievable (ALARA) radiation dose.

Key Points

? 128-slice dual-source CT coronary angiography offers several different acquisition protocols. ? Randomized comparison of protocols reveals an optimal protocol selection strategy. ? Appropriate CTCA protocol selection lowers radiation dose, while maintaining high quality. ? CTCA protocol selection should be based on individual patient characteristics. ? A prospective sequential protocol is preferred for CTCA.     

Comparison of left ventricular function assessment using phonocardiogram- and electrocardiogram-triggered 2D SSFP CINE MR imaging at 1.5 T and 3.0 T

Objective

As high-field cardiac MRI (CMR) becomes more widespread the propensity of ECG to interference from electromagnetic fields (EMF) and to magneto-hydrodynamic (MHD) effects increases and with it the motivation for a CMR triggering alternative. This study explores the suitability of acoustic cardiac triggering (ACT) for left ventricular (LV) function assessment in healthy subjects (n?=?14).

Methods

Quantitative analysis of 2D CINE steady-state free precession (SSFP) images was conducted to compare ACT’s performance with vector ECG (VCG). Endocardial border sharpness (EBS) was examined paralleled by quantitative LV function assessment.

Results

Unlike VCG, ACT provided signal traces free of interference from EMF or MHD effects. In the case of correct R-wave recognition, VCG-triggered 2D CINE SSFP was immune to cardiac motion effects—even at 3.0 T. However, VCG-triggered 2D SSFP CINE imaging was prone to cardiac motion and EBS degradation if R-wave misregistration occurred. ACT-triggered acquisitions yielded LV parameters (end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF) and left ventricular mass (LVM)) comparable with those derived from VCG-triggered acquisitions (1.5 T: ESV_VCG?=?(56?±?17) ml, EDV_VCG?=?(151?±?32) ml, LVM_VCG?=?(97?±?27) g, SV_VCG?=?(94?±?19) ml, EF_VCG?=?(63?±?5)% cf. ESV_ACT?=?(56?±?18) ml, EDV_ACT?=?(147?±?36) ml, LVM_ACT?=?(102?±?29) g, SV_ACT?=?(91?±?22) ml, EF_ACT?=?(62?±?6)%; 3.0 T: ESV_VCG?=?(55?±?21) ml, EDV_VCG?=?(151?±?32) ml, LVM_VCG?=?(101?±?27) g, SV_VCG?=?(96?±?15) ml, EF_VCG?=?(65?±?7)% cf. ESV_ACT?=?(54?±?20) ml, EDV_ACT?=?(146?±?35) ml, LVM_ACT?=?(101?±?30) g, SV_ACT?=?(92?±?17) ml, EF_ACT?=?(64?±?6)%).

Conclusions

ACT’s intrinsic insensitivity to interference from electromagnetic fields renders it suitable for clinical CMR.     

Automated Quantification of Epicardial Adipose Tissue Using CT Angiography: Evaluation of a Prototype Software

Objectives

This study evaluated the performance of a novel automated software tool for epicardial fat volume (EFV) quantification compared to a standard manual technique at coronary CT angiography (cCTA).

Methods

cCTA data sets of 70 patients (58.6?±?12.9 years, 33 men) were retrospectively analysed using two different post-processing software applications. Observer 1 performed a manual single-plane pericardial border definition and EFV_M segmentation (manual approach). Two observers used a software program with fully automated 3D pericardial border definition and EFV_A calculation (automated approach). EFV and time required for measuring EFV (including software processing time and manual optimization time) for each method were recorded. Intraobserver and interobserver reliability was assessed on the prototype software measurements. T test, Spearman’s rho, and Bland–Altman plots were used for statistical analysis.

Results

The final EFV_A (with manual border optimization) was strongly correlated with the manual axial segmentation measurement (60.9?±?33.2 mL vs. 65.8?±?37.0 mL, rho?=?0.970, P?<?0.001). A mean of 3.9?±?1.9 manual border edits were performed to optimize the automated process. The software prototype required significantly less time to perform the measurements (135.6?±?24.6 s vs. 314.3?±?76.3 s, P?<?0.001) and showed high reliability (ICC?>?0.9).

Conclusions

Automated EFV_A quantification is an accurate and time-saving method for quantification of EFV compared to established manual axial segmentation methods.

Key Points

? Manual epicardial fat volume quantification correlates with risk factors but is time-consuming. ? The novel software prototype automates measurement of epicardial fat volume with good accuracy. ? This novel approach is less time-consuming and could be incorporated into clinical workflow.     

Treatment outcomes of patients with cervical cancer with complete metabolic responses after definitive chemoradiotherapy

Purpose

We sought to evaluate failure patterns and prognostic factors predictive of recurrences and survival in cervical cancer patients who are treated with definitive chemoradiotherapy (ChRT), who have a subsequent complete metabolic response (CMR) with ¹⁸?F-fluorodeoxyglucose positron-emission tomography (FDG-PET) after treatment.

Methods

The records of 152 cervical cancer patients who were treated with definitive chemoradiotherapy were evaluated. All patients underwent pre-treatment positron emission tomography (PET-CT), and post-treatment PET-CT was performed within a median of 3.9 months (range, 3.0–9.8 months) after the completion of ChRT. The prognoses of partial response/progressive disease (PR/PD) cases (30 patients, 18 %) and CMR cases (122 patients, %82) were evaluated. Univariate and multivariate analysis effecting the treatment outcome was performed in CMR cases.

Results

The median follow-ups for all patients and surviving patients were 28.7 (range, 3.3–78.7 months) and 33.2 months (range, 6.23–78.7 months), respectively. Four-year overall survival (OS) rate was significantly better in patients with CMR compared to patients with PR/PD (66.9 % vs. 12.4 %, p?<?0.001, respectively). Patients with PR/PD had higher maximum standardized uptake value (SUV_max) of primary cervical tumor (26.4?±?10.1 vs. 15.9?±?6.3; p?<?0.001) and larger tumor (6.4 cm?±?2.3 cm vs. 5.0 cm?±?1.4 cm; p?<?0.001) compared to patients with CMR. Of the 122 patients with post-treatment CMRs, 25 (21 %) developed local, locoregional, or distant failure. In univariate analysis, tumor size ≥ 5 cm, ‘International Federation of Obstetricians and Gynecologists’ (FIGO) stage?≥?IIB, and pelvic and/or para-aortic lymph node metastasis were predictive of both overall survival (OS) and disease-free survival (DFS), while histology was predictive of only OS. In multivariate analysis, tumor size, stage and lymph node metastasis were predictive of OS and DFS.

Conclusion

Although CMR is associated with better outcomes, relapses remain problematic, especially in patients with bulky tumors (≥ 5 cm), extensive stage (≥ IIB) or pelvic and/or para-aortic lymph node metastasis. These findings could support the need for more aggressive treatment or adjuvant chemotherapy regimens.     

Multiple antiplatelet therapy contributes to the reversible high signal spots on diffusion-weighted imaging in elective coiling of unruptured cerebral aneurysm

Introduction

Our aim was to systematically investigate radiographic characteristics and outcome of diffusion-weighted imaging (DWI) changes in the elective coiling of unruptured cerebral aneurysm with analyzing the correlation of antiplatelet therapy (APT).

Methods

In a total of 34 consecutive patients with unruptured cerebral aneurysms initially treated by coiling without stent assist, 26 (76.5 %) had DWI changes with 91 high signal spots within 24–48 h after the procedure. We recorded DWI parameters (location, volume, mean, and minimum values of the apparent diffusion coefficient: expressed as ADC_AVE and ADC_MIN) for each lesion, and evaluated its radiographic outcome on conventional MRI at follow-up (interval, 58.4?±?37.2 days) in the modes of APT.

Results

All patients with DWI high spots had no clinical symptoms. There was a strong correlation between ADC_AVE and ADC_MIN (r?=?0.82, p?<?0.0001). The mean ADC_AVE and rADC_AVE were 0.74?±?0.14?×?10^?3?mm²/s and 87?±?10 %. DWI high spots were small with a mean volume of 0.13?±?0.12 cm³, ranging from 0.04 to 0.86 cm³. A negative correlation was observed between the volume and values of ADC_AVE (r?=??0.48, p?<?0.0001). The DWI volume was significantly larger in single APT than in multiple (0.15?±?0.14 versus 0.10?±?0.07 cm³, p?=?0.0091). The permanent signal change was more observed in single APT than in multiple (24.5 % versus 5.2 %, p?=?0.02).

Conclusion

DWI high spots after elective coiling were small without significant decrease of ADC, and do not correspond to brain infarction. Periprocedural use of multiple antiplatelet agents is expected to reduce the volume of thromboembolism and permanent tissue damages.     

Comparison of three multichannel transmit/receive radiofrequency coil configurations for anatomic and functional cardiac MRI at 7.0T: implications for clinical imaging

Objectives

To implement, examine, and compare three multichannel transmit/receive coil configurations for cardiovascular MR (CMR) at 7T.

Methods

Three radiofrequency transmit-receive (TX/RX) coils with 4-, 8-, and 16-coil elements were used. Ten healthy volunteers (seven males, age 28?±?4?years) underwent CMR at 7T. For all three RX/TX coils, 2D CINE FLASH images of the heart were acquired. Cardiac chamber quantification, signal-to-noise ratio (SNR) analysis, parallel imaging performance assessment, and image quality scoring were performed.

Results

Mean total examination time was 29?±?5?min. All images obtained with the 8- and 16-channel coils were diagnostic. No significant difference in ejection fraction (EF) (P?>?0.09) or left ventricular mass (LVM) (P?>?0.31) was observed between the coils. The 8- and 16-channel arrays yielded a higher mean SNR in the septum versus the 4-channel coil. The lowest geometry factors were found for the 16-channel coil (mean ± SD 2.3?±?0.5 for R?=?4). Image quality was rated significantly higher (P?Conclusions All three coil configurations are suitable for CMR at 7.0T under routine circumstances. A larger number of coil elements enhances image quality and parallel imaging performance but does not impact the accuracy of cardiac chamber quantification.

Key Points

? Cardiac chamber quantification using 7.0T magnetic resonance imaging is feasible. ? Examination times for cardiac chamber quantification at 7.0T match current clinical practice. ? Multichannel transceiver RF technology facilitates improved image quality and parallel imaging performance. ? Increasing the number of RF channels does not influence cardiac chamber quantification.     

Tumour volume doubling time of molecular breast cancer subtypes assessed by serial breast ultrasound

Objectives

The aim of our study was to evaluate the tumour volume doubling time (TVDT) of molecular breast cancer subtypes by serial ultrasound (US).

Methods

Sixty-six patients (mean age, 50 years; range, 29–78 years) with invasive breast cancer underwent initial and follow-up breast US examinations (at least three months apart) with no intervention. TVDT was determined using the tumours’ greatest dimensions in two orthogonal planes. The results were compared with clinical, imaging, and tumour variables and molecular subtypes (oestrogen receptor [ER]-positive, human epidermal growth factor receptor 2 [HER2]-positive, and triple negative) using a multiple linear regression analysis.

Results

TVDT exhibited a wide range (46–825 days; median, 141 days) with an overall mean of 193?±?141 days and mean values of 241?±?166 days for ER-positive tumours (n?=?37), 162?±?60 days for HER2-positive tumours (n?=?12), and 103?±?43 days for triple-negative tumours (n?=?17) (P?P?Conclusions TVDT differed significantly among the three molecular breast cancer subtypes, with the triple-negative tumours showing the fastest growth.

Key Points

? Knowledge of tumour volume doubling time provides clues for improving screening. ? TVDT assessed by serial US differed significantly between breast cancer subtypes. ? Triple-negative tumours had 2.4-fold shorter TVDT compared to ER-positive tumours. ? Tumours classified as BI-RADS 3 had shorter TVDT than BI-RADS 4.     

Upright Cone CT of the hindfoot: Comparison of the non-weight-bearing with the upright weight-bearing position

Objectives

To prospectively compare computed tomography (CT) of the hindfoot in the supine non-weight-bearing position (NWBCT) with upright weight-bearing position (WBCT).

Methods

Institutional review board approval and informed consent of all patients were obtained. NWBCT and WBCT scans of the ankle were obtained in 22 patients (mean age, 46.0?±?17.1 years; range 19–75 years) using a conventional 64-row CT for NWBCT and a novel cone-beam CT for WBCT. Two musculoskeletal radiologists independently performed the following measurements: the hindfoot alignment angle, fibulocalcaneal and tibiocalcaneal distances, lateral talocalcaneal joint space width, talocalcaneal overlap and naviculocalcaneal distance. Significant changes between NWBCT and WBCT were sought using Wilcoxon signed-rank test. P values <0.05 were considered statistically significant.

Results

Significant differences were found for all measurements except the hindfoot alignment angle and tibiocalcaneal distance. Significant measurement results were as follows (NWBCT/WBCT reader 1; NWBCT/WBCT reader 2, mean ± standard deviation): fibulocalcaneal distance 3.6 mm?±?5.2/0.3 mm?±?6.0 (P?=?0.006); 1.4 mm?±?6.3/-1.1 mm?±?6.3 (P?=?0.002), lateral talocalcaneal joint space width 2.9 mm?±?1.7/2.2 mm?±?1.1 (P?=?0.005); 3.4 mm?±?1.9/2.4 mm?±?1.3 (P?=?0.001), talocalcaneal overlap 4.1 mm?±?3.9/1.4 mm?±?3.9 (P?=?0.001); 4.5 mm?±?4.3/1.4 mm?±?3.7 (P?<?0.001) and naviculocalcaneal distance 13.5 mm?±?4.0/15.3 mm?±?4.7 (P?=?0.037); 14.0 mm?±?4.4/15.7 mm?±?6.2 (P?=?0.100). Interreader agreement was good to excellent (ICC 0.48–0.94).

Conclusion

Alignment of the hindfoot significantly changes in the upright weight-bearing CT position. Differences can be visualised and measured using WBCT.

Key Points

? Cone-beam computed tomography (CBCT) offers new opportunities for musculoskeletal problems ? Visualization and quantification of hindfoot alignment are possible in upright weight-bearing CBCT ? Hindfoot alignment changes significantly from non-weight-bearing to weight-bearing CT ? The weight-bearing position leads to a decrease in the fibulocalcaneal distance and talocalcaneal overlap ? The naviculocalcaneal distance is increased in the weight-bearing position     

Image noise-based dose adaptation in dynamic volume CT of the heart: dose and image quality optimisation in comparison with BMI-based dose adaptation

Objectives

To compare the image quality and radiation dose using image-noise (IN)-based determination of X-ray tube settings compared with a body mass index (BMI)-based protocol during CT coronary angiography (CTCA).

Methods

Two hundred consecutive patients referred for CTCA to our institution were divided into two groups: BMI-based, 100 patients had CTCA with the X-ray tube current adjusted to the patient’s BMI while maintaining a fixed tube potential of 120 kV; IN-based, 100 patients underwent imaging with the X-ray tube current and voltage adjusted to the IN measured within the mid-left ventricle on a pre-acquisition trans-axial image. Two independent cardiac radiologists performed blinded image quality assessment with quantification of the IN and signal-to-noise ratio (SNR) from the mid-LV and qualitative assessment using a three-point score. Radiation dose (CTDI and DLP) was recorded from the console.

Results

Results showed: IN (HU): BMI-based, 30.1?±?9.9; IN-based, 33.1?±?6.7; 32 % variation reduction (P?=?0.001); SNR: BMI-based, 18.6?±?7.1; IN-based, 15.4?±?3.7; 48 % variation reduction (P?<?0.0001). Visual scores: BMI-based, 2.3?±?0.6; IN-based, 2.2?±?0.5 (P?=?0.54). Radiation dose: CTDI (mGy), BMI-based, 22.68?±?8.9; IN-based, 17.16?±?7.6; 24.3 % reduction (P?<?0.001); DLP (mGy.cm), BMI-based, 309.3?±?127.5; IN-based, 230.6?±?105.5; 25.4 % reduction (P?<?0.001).

Conclusions

Image-noise-based stratification of X-ray tube parameters for CTCA results in 32 % improvement in image quality and 25 % reduction in radiation dose compared with a BMI-based protocol.

Key Points

? Image quality and radiation dose are closely related in CT coronary angiography. ? So too are the image quality, radiation dose and body mass index (BMI). ? An image-noise-based CTCA protocol reduces the radiation dose by 25 %. ? It improves inter-patient image homogeneity by 32 %.     

Radiofrequency ablation of benign non-functioning thyroid nodules: 4-year follow-up results for 111 patients

Objectives

To evaluate the clinical outcomes and safety of radiofrequency (RF) ablation for benign non-functioning thyroid nodules over a 4-year follow-up.

Methods

We evaluated 126 benign non-functioning thyroid nodules of 111 patients treated with RF ablation and followed-up more than 3 years. RF ablation was performed using the Cool-Tip RF system and an internally cooled electrode. Nodule volume and cosmetic and symptom scores were evaluated before treatment and during follow-up. Complications and factors related to efficacy were evaluated.

Results

The mean follow-up duration was 49.4?±?13.6 months. Thyroid nodule volume decreased significantly, from 9.8?±?8.5 ml before ablation to 0.9?±?3.3 ml (P?<?0.001) at final evaluation: a mean volume reduction of 93.4?±?11.7 %. The mean cosmetic (P?<?0.001) and symptom scores (P?<?0.001) improved significantly. Factors related to efficacy were initial solidity and volume. The overall recurrence rate was 5.6 % (7/126). The overall complication rate was 3.6 % (4/111).

Conclusions

RF ablation was effective in shrinking benign thyroid nodules and in controlling nodule-related problems over a 4-year follow-up. There were no life-threatening complications or sequelae. Therefore, RF ablation can be used as a non-surgical treatment for patients with benign non-functioning thyroid nodules.

Key Points

? Radiofrequency (RF) ablation provides a non-surgical option for benign non-functioning thyroid nodules ? RF ablation reduced non-functioning thyroid nodular volume by 93.5 % after 49 months ? Initial solidity and volume influenced the efficacy of RF ablation ? Larger thyroid nodules required more treatment sessions to achieve appropriate volume reduction ? Complete treatment of the periphery of the nodule is important in preventing marginal regrowth     

Heritability, determinants and reference values of renal length: a family-based population study

Objectives

In this population-based study, reference values were generated for renal length, and the heritability and factors associated with kidney length were assessed.

Methods

Anthropometric parameters and renal ultrasound measurements were assessed in randomly selected nuclear families of European ancestry (Switzerland). The adjusted narrow sense heritability of kidney size parameters was estimated by maximum likelihood assuming multivariate normality after power transformation. Gender-specific reference centiles were generated for renal length according to body height in the subset of non-diabetic non-obese participants with normal renal function.

Results

We included 374 men and 419 women (mean ± SD, age 47?±?18 and 48?±?17 years, BMI 26.2?±?4 and 24.5?±?5 kg/m², respectively) from 205 families. Renal length was 11.4?±?0.8 cm in men and 10.7?±?0.8 cm in women; there was no difference between right and left renal length. Body height, weight and estimated glomerular filtration rate (eGFR) were positively associated with renal length, kidney function negatively, age quadratically, whereas gender and hypertension were not. The adjusted heritability estimates of renal length and volume were 47.3?±?8.5 % and 45.5?±?8.8 %, respectively (P?<?0.001).

Conclusion

The significant heritability of renal length and volume highlights the familial aggregation of this trait, independently of age and body size. Population-based references for renal length provide a useful guide for clinicians.

Key Points

? Renal length and volume are heritable traits, independent of age and size. ? Based on a European population, gender-specific reference values/percentiles are provided for renal length. ? Renal length correlates positively with body length and weight. ? There was no difference between right and left renal lengths in this study. ? This negates general teaching that the left kidney is larger and longer.     

An optimised patient-specific approach to administration of contrast agent for CT pulmonary angiography

Objectives

To investigate pulmonary vasculature opacification during CTPA using an optimised patient-specific protocol for administering contrast agent.

Methods

CTPA was performed on 200 patients with suspected PE. Patients were assigned to two protocol groups: protocol A, fixed 80 ml contrast agent; protocol B used a patient-specific approach. The mean cross-sectional opacification profile of 8 central and 11 peripheral pulmonary arteries and veins was measured and the arteriovenous contrast ratio (AVCR) calculated. Protocols were compared using Mann–Whitney U non-parametric statistics. Jack-knife alternative free-response receiver-operating characteristic (JAFROC) analyses assessed diagnostic efficacy. Interobserver variations were investigated using kappa methods.

Results

A number of pulmonary arteries demonstrated increases in opacification (P?<?0.03) for protocol B compared to A, whilst opacification in the heart and veins was reduced in protocol B (P?=?0.05). Increased AVCR in protocol B compared with A was observed at all anatomic locations (P?<?0.0002). Increased JAFROC (P?<?0.0002) and kappa variation were observed with protocol B (κ?=?0.78) compared to A (κ?=?0.25). Mean contrast volume was reduced in protocol B (33?±?9 ml) compared to A (80?±?1 ml).

Conclusions

Significant improvements in visualisation of the pulmonary vasculature can be achieved with a low volume of contrast agent using injection timing based on a patient-specific contrast formula.

Key points

? Optimal opacification of the pulmonary arteries is essential for CT pulmonary angiography. ? Matching timing with vessel dynamics significantly improves vessel opacification. ? This leads to increased arterial opacification and reduced venous opacification. ? This can also lead to a reduced volume of contrast agent.