Discrepancies in determination of abdominal aortic aneurysms maximum diameter and growth rate,using axial and orhtogonal computed tomography measurements

Purpose

Maximum diameter and growth rate of abdominal aortic aneurysms (AAAs) which are currently used as the only variables to set the indication for elective repair are recorded through computed tomography (CT) measurements on an axial plane or on an orthogonal plane that is perpendicular to vessel centerline, interchangeably. We will attempt to record possible discrepancies between the two methods, identify whether such differences could influence therapeutic decisions and determine in which cases this should be expected.

Materials and methods

We retrospectively reviewed sixty CT-scans performed in thirty-nine patients. Three-dimensional reconstruction of AAAs has been performed and differences in maximum diameter measured on axial and orthogonal planes were recorded. A measure for asymmetry was introduced termed ShapeIndex defined as the value of section minor over major axis and was related with differences in maximum diameter recordings. Growth rates were also determined using both axial and orthogonal measurements.

Results

Axial measurements overestimate maximum diameter by 2 ± 2.7 mm (P < 0.001) with a range of 0–12.3 mm. Overall, 20% of the CTs had an axial maximum diameter >5.5 cm indicating the need for intervention whereas, orthogonal diameter was below that threshold. Asymmetry of the axial sections with ShapeIndex ≤ 0.8 was found to be related to an overestimation of maximum diameter by >5 mm. There were no significant differences in growth rates when determined using orthogonal or axial measurements in both examinations (median growth rate: 2.3 mm and 3.3 mm respectively P = 0.2). However there were significant differences when orthogonal measurements were used at initial and axial measurements used at follow-up examination or vice versa (median growth rate: 4.9 mm and 0.9 mm respectively P < 0.001).

Conclusions

Although the mean difference between measurements is low there is a wide range among cases, mainly observed in asymmetrical AAAs. ShapeIndex may identify those which are more likely to be misestimated. CT measurements performed to establish AAA growth rates should consistently use either the axial or orthogonal technique to avoid inaccuracies from occurring.     

Measurements and detection of abdominal aortic aneurysm growth: Accuracy and reproducibility of a segmentation software

Purpose

To validate the reproducibility and accuracy of a software dedicated to measure abdominal aortic aneurysm (AAA) diameter, volume and growth over time.

Materials and methods

A software enabling AAA segmentation, diameter and volume measurement on computed tomography angiography (CTA) was tested. Validation was conducted in 28 patients with an AAA having 2 consecutive CTA examinations. The segmentation was performed twice by a senior radiologist and once by 3 medical students on all 56 CTAs. Intra and inter-observer reproducibility of D-max and volumes values were calculated by intraclass correlation coefficient (ICC). Systematic errors were evaluated by Bland–Altman analysis. Differences in D-max and volume growth were compared with paired Student's t-tests.

Results

Mean D-max and volume were 49.6 ± 6.2 mm and 117.2 ± 36.2 ml for baseline and 53.6 ± 7.9 mm and 139.6 ± 56.3 ml for follow-up studies. Volume growth (17.3%) was higher than D-max progression (8.0%) between baseline and follow-up examinations (p < .0001). For the senior radiologist, intra-observer ICC of D-max and volume measurements were respectively estimated at 0.997 (≥0.991) and 1.000 (≥0.999). Overall inter-observer ICC of D-max and volume measurements were respectively estimated at 0.995 (0.990–0.997) and 0.999 (>0.999). Bland–Altman analysis showed excellent inter-reader agreement with a repeatability coefficient <3 mm for D-max, <7% for relative D-max growth, <6 ml for volume and <6% for relative volume growth.

Conclusion

Software AAA volume measurements were more sensitive than AAA D-max to detect AAA growth while providing an equivalent and high reproducibility.     

Aortic volume as an indicator of disease progression in patients with untreated infrarenal abdominal aneurysm

Objective

The maximal diameter of an abdominal aortic aneurysm (AAA) and the change in diameter over time reflect rupture risk and are used for surgical planning. However, evidence has emerged that aneurysm volume may be a better indicator of AAA remodeling. The purpose of this study was to assess the relationship between the volume and maximal diameter of the abdominal aorta in patients with untreated infrarenal AAA.

Materials and methods

This was a retrospective study of 100 patients with infrarenal AAA who were followed for more than 6 months. We examined 2 sets of computed tomography images for each patient, acquired ≥6 months apart. The maximal diameter and volume of the infrarenal abdominal aorta were determined by semiautomated segmentation software.

Results

At baseline, mean maximal infrarenal diameter was 5.1 ± 1.0 cm and mean aortic volume was 139 ± 72 mL. There was good correlation between the maximal diameter and aortic volume at baseline (r² = 0.55; P < 0.001). The mean change in maximal diameter between studies was 0.2 ± 0.3 cm and the mean volume change was 19 ± 19 mL. However, the correlation between diameter change and volume change was modest (r² = 0.34; P = 0.001). Most patients (n = 64) had no measurable change in maximal diameter between studies (≤2 mm), but the change in volume was found to vary widely (−2 to 69 mL).

Conclusion

In patients with untreated infrarenal AAA, a change in aortic volume can occur in the absence of a significant change in maximal diameter. Additional work is needed to examine the relationship between change in AAA volume and outcomes in this patient group.     

Correlation of FDG PET/CT Findings with Long-Term Growth and Clinical Course of Abdominal Aortic Aneurysm

Purpose

Herein, we report characteristics of ¹⁸F–fluorodeoxyglucose (FDG) uptake in abdominal aortic aneurysms (AAAs) during a long-term follow-up. In addition, we investigated the association between FDG uptake and the physician decision to perform an intervention.

Methods

We performed a retrospective review of 42 patients with AAAs who underwent FDG positron emission tomography (PET)/computed tomography (CT). The size of the AAA was measured in serial CT or PET/CT images. The long-term growth rate of AAAs was calculated by linear regression of the size change. Maximal SUV of the AAA (SUV_AAA) and mean SUV of the blood pool (SUV_Blood) were measured in PET/CT fusion images. To assess the FDG uptake of AAAs, the target-to-background ratio (TBR) was defined as the ratio of SUV_AAA to SUV_Blood. We compared FDG uptake of AAAs with the long-term growth rate of AAAs and clinical data.

Results

TBR was not significantly different between patients with and without significant growth (1.55 ± 0.20 vs. 1.57 ± 0.14; P = 0.5599). However, in patients with significant growth, TBR exhibited a significant positive correlation with the growth rate (r ²  = 0.2601, P = 0.0306). TBR also exhibited a significant difference between patients with and without intervention (P = 0.0228).

Conclusion

FDG uptake of AAA is associated with long-term growth of AAAs in a specified group that exhibits growth. FDG PET/CT may only be effective in predicting the long-term growth of AAAs in specific subgroups of patients. It is also suggested that FDG PET is potentially related to the clinical conditions of AAA patients who need surgical or interventional treatment.

     

腹主动脉瘤附壁血栓分布规律和相关因素分析

目的:研究腹主动脉瘤(AAA)附壁血栓(ILT)的生长规律,探讨ILT与年龄、性别、AAA直径的关系。方法:对103例AAA连续病例行CT扫描,观察有无ILT及ILT的分布规律,测量AAA直径和ILT最大厚度,分析ILT与年龄、性别及动脉瘤大小的关系。结果:66．9％AAA有ILT,女性AAA有ILT较少见(15．4%)。ILT与AAA直径、患者年龄相关,AAA直径小于40mm时形成ILT的比例为21．4％,年龄小于60岁时形成ILT的比例为25．0％。以近端瘤颈截面的中心和髂动脉分叉做一连线,血栓总是分布在距离该轴线较远的瘤壁。结论瘤体内血流可能是ILT形成的重要因素;女性和年龄小于60岁不易形成血栓,提示ILT的形成是多因素的。     

CT after Endovascular Repair of Abdominal Aortic Aneurysms: Diagnostic Accuracy of Diameter Measurements for the Detection of Aneurysm Sac Enlargement

Purpose

To evaluate the diagnostic accuracy of diameter measurements for the detection of aneurysm volume increase during follow-up after endovascular aortic repair (EVAR) of abdominal aortic aneurysms (AAAs).

Influence of Statin Therapy on Aneurysm Sac Regression after Endovascular Aortic Repair

Purpose

To determine whether statin therapy is associated with abdominal aortic aneurysm (AAA) sac regression after endovascular aneurysm repair (EVAR).

Follow-up of abdominal aortic aneurysm after endovascular aortic repair: comparison of volumetric and diametric measurement

Purpose

To determine the correlation of maximal diameter measurements with volumetric evaluation of size after endovascular aortic repair (EVAR) of abdominal aortic aneurysms (AAA) using computed tomography angiography (CTA) and to survey its applicability for clinical follow-up.

Materials and methods

73 consecutive patients (2 females, 71 males; age 38–84 years; mean age, 69.1 ± 8 years) with AAA were treated with percutaneous EVAR in a single institution. For follow-up, CTA was performed periodically after EVAR. Images were evaluated for maximal diameter in consensus by two experienced radiologists. Using OsirixTM, volumetric measurements were done by one radiologist, including the entire infrarenal abdominal aorta.

Results

In 73 patients 220 CTA examinations were performed after EVAR with a mean follow-up of 17.3 months (range, 1.8–42.7 months). The mean postinterventional volume of aneurysm was 165.63 ml ± 93.29 ml (range, 47.94–565.67 ml). The mean maximal postinterventional diameter was 5.91 ± 1.52 cm (range, 3.72–13.82 cm). At large over the entire observation period a slight, non-significant decrease of 1.6% (2.58 ml ± 69.05 ml, range 82.82–201.92 ml) in volumes and a 9.3% (mean 0.55 cm ± 1.22 cm, range 2.85–1.93 cm) in diameters were observed. For all examinations a high correlation of volume and diameter was calculated (r = 0.813–0.905; α < 0.01).

Conclusion

For follow-up of abdominal EVAR using CTA there is a high correlation between volumetric and diametric measurements of aneurysm. Based on a daily clinical routine setting, measurements of maximal diameters in cross sectional imaging of AAA after EVAR seems to be sufficient to exclude post interventional enlargement.     

Categorization of aortic aneurysm thrombus morphology by magnetic resonance imaging

Background

Magnetic resonance imaging (MRI) has been proposed for qualitative categorization of intraluminal thrombus morphology. We aimed to correlate the qualitative MRI categorization previously described to quantitative measurements of signal intensity and to compare morphological characteristics of intraluminal thrombus specimens to the appearance on magnetic resonance imaging.

Methods

Thirty-four patients undergoing open surgery for abdominal aortic aneurysm had a preoperative MRI obtained with a 1.5 T magnet. Qualitative categorization was performed (blinded and in consensus) and correlated to intraluminal thrombus to muscle signal-intensity ratios. Morphology of intraluminal thrombus specimens collected during surgery were compared to the magnetic resonance imaging categories and specimen weight was correlated to thrombus volume measured on preoperative computer tomography angiography.

Results

Blinded MRI categorization resulted in agreement in 22 out of 34 intraluminal thrombi (Kappa value 0.3, p = 0.006). Medians (p = 0.004) and distribution (p = 0.002) of signal-intensity ratios varied significantly across the three MRI categories obtained by consensus. Heterogeneous and homogenous specimen appearance corresponded to similar appearances on MRI in 78% and 55% respectively, resulting in an overall Kappa = 0.4 (p = 0.04). Intraluminal thrombus volume and weight correlated well (r_s 0.831, p < 0.001) with a mean difference of 60 g (95% CI 38–80 g), without proportional bias.

Conclusion

Qualitative evaluation of intraluminal thrombus morphology based on MRI can be quantified by measuring signal-intensity ratios. Concurrently a fair agreement to blinded qualitative evaluation of thrombus specimens can be obtained. However, the evaluation is impaired by loss of a large proportion of thrombus during sampling.     

Post-mortem virtual estimation of free abdominal blood volume

Purpose

The purpose of this retrospective study was to examine the reliability of virtually estimated abdominal blood volume using segmentation from postmortem computed tomography (PMCT) data.

Materials and methods

Twenty-one cases with free abdominal blood were investigated by PMCT and autopsy. The volume of the blood was estimated using a manual segmentation technique (Amira, Visage Imaging, Germany) and the results were compared to autopsy data. Six of 21 cases had undergone additional post-mortem computed tomographic angiography (PMCTA).

Results

The virtually estimated abdominal blood volumes did not differ significantly from those measured at autopsy. Additional PMCTA did not bias data significantly.

Conclusion

Virtual estimation of abdominal blood volume is a reliable technique. The virtual blood volume estimation is a useful tool to deliver additional information in cases where autopsy is not performed or in cases where a postmortem angiography is performed.     

Can left ventricular end-diastolic volumes be estimated with prospective ECG-gated CT coronary angiography?

Background

With the goal of minimizing patient radiation exposure, many centres have adopted prospective ECG-gated computed tomographic coronary angiography. Since image acquisition occurs only during ventricular diastasis, the ability to measure left ventricular (LV) ejection fraction (EF) and LV volumes has been lost. Given that LV volumes have prognostic value, the ability to estimate LV end diastolic volume (EDV) may be clinically desirable.

Objective

We sought to predict LV EDV using CT coronary angiography (CTA) images obtained during ventricular diastasis.

Methods

Consecutive patients who underwent retrospective ECG-gated CTA were enrolled. Images were reconstructed at the 75% phase and at end-diastole. LV and left atrial (LA) volumes were measured.

Results

A total of 153 consecutive patients were analyzed (mean age = 56.7 ± 11.2 years; men = 56.2%). The mean LV EDV and EF were 144.4 ± 40.2 mL and 63.4 ± 9.9%, respectively. There appeared to be a very strong linear relationship between the 75% phase LV volume and LV EDV with an R² of 0.993. Using LV and LA volumes at the 75% phase, a prediction model of LV EDV was developed (LV EDV = (1.021 × 75% phase LV volume) + (0.259 × 75% phase LA volume), adjusted R² = 0.995).

Conclusion

LV EDV can be estimated using CTA data obtained during ventricular diastasis. Further studies are needed to demonstrate that such estimates of LV EDV have incremental prognostic value over coronary artery disease severity assessment with prospective ECG-gated CTA.     

Low baseline and subsequent higher aortic abdominal aneurysm FDG uptake are associated with poor sac shrinkage post endovascular repair

Purpose

The growth phases of medically treated abdominal aortic aneurysms (AAA) are frequently associated with an ¹⁸F–fluorodesoxyglucose positron emission tomography (FDG-PET) pattern involving low baseline and subsequent higher FDG uptake. However, the FDG-PET patterns associated with the endovascular aneurysm repair (EVAR) of larger AAA are presently unknown. This study aimed to investigate the relationship between serial AAA FDG uptake measurements, obtained before EVAR and 1 and 6 months post-intervention and subsequent sac shrinkage at 6 months, a well-recognized indicator of successful repair.

Methods

Thirty-three AAA patients referred for EVAR (maximal diameter: 55.4?±?6.0 mm, total volume: 205.7?±?63.0 mL) underwent FDG-PET/computed tomography (CT) before EVAR and at 1 and 6 months thereafter, with the monitoring of AAA volume and of a maximal standardized FDG uptake [SUVmax] averaged between the axial slices encompassing the AAA.

Results

Sac shrinkage was highly variable and could be stratified into three terciles: a first tercile in which shrinkage was absent or very limited (0–29 mL) and a third tercile with pronounced shrinkage (56–165 mL). SUVmax values were relatively low at baseline in the 1st tercile (SUVmax: 1.69?±?0.33), but markedly increased at 6 months (2.42?±?0.69, p?=?0.02 vs. baseline). These SUV max values were by contrast much higher at baseline in the 3rd tercile (SUVmax: 2.53?±?0.83 p?=?0.009 vs. 1st tercile) and stable at 6 months (2.49?±?0.80), while intermediate results were documented in the 2nd tercile. Lastly, the amount of sac shrinkage, expressed in absolute values or in percentages of baseline AAA volumes, was positively correlated with baseline SUVmax (p?=?0.001 for both).

Conclusion

A low pre-EVAR FDG uptake and increased AAA FDG uptake at 6 months are associated with reduced sac shrinkage. This sequential FDG-PET pattern is similar to that already shown to accompany growth phases of medically treated AAA.

     

Acute traumatic injuries of thoracic aorta: Role of 64-MDCTA in diagnosis and management

Objectives

Review our experience with 64-MDCTA in diagnosis and management of patients with acute traumatic injury of thoracic aorta.

Patients and methods

Thirty-five patients with possible traumatic aortic injury were subjected to 64-MDCTA. Arterial and delayed phases were acquired for chest, abdomen and pelvis. Positive findings were encountered in 24 patients, surgical repair done for 7 cases, endovascular repair for 14 cases and follow up for 1 case. Two patients died before intervention. The remaining 11 patients had no direct signs of ATAI and their follow up was uneventful. All cases planned for EVR were subjected to conventional aortography as part of the treatment process. MDCTA findings were compared with surgical, aortography findings and clinic-radiologic follow up.

Results

Direct positive MDCTA findings in 24 cases included pseudoaneurysm (23), transection (15), intimal tear (12), intimal flap (10), intramural–intraluminal hematoma (1) and active bleeding (3). Mediastinal hematoma as an indirect sign was detected in all cases. MDCTA findings correlated well with surgical and aortography findings.

Conclusion

Stable patients with potential ATAI should be subjected first to urgent MDCTA. This will offer rapid reliable diagnosis, plan intervention and avoid invasive aortography that will be indicated only if endovascular repair is decided.     

A longitudinal study of brain volume changes in normal aging

Purpose

To evaluate the effect of normal aging on brain volumes and examine the effects of age and sex on the rates of changes in global and regional brain volumes.

Methods

A total of 199 normal subjects (65 females and 134 males, mean age = 56.4 ± 9.9 years, age range = 38.1–82.9 years) were included in this study. Each subject was scanned twice, at an interval of about 2 years (range = 1.5–2.3 years). Two-time-point percentage brain volume change (PBVC) was estimated with SIENA 2.6.

Results

The mean annualized PBVC was −0.23%/y. Analysis of covariance (ANCOVA) for annual brain volume changes revealed a main effect of age. There was no main effect of sex, nor was there a sex-by-age interaction. Voxel-wise analysis revealed a negative correlation between age and edge displacement values mainly in the periventricular region.

Conclusions

The results of our study indicate that brain atrophy accelerates with increasing age and that there is no gender difference in the rate of brain atrophy.     

Quantification of aortic distensibility in abdominal aortic aneurysm using ECG-gated multi-detector computed tomography

Rationale and objectives

To detect distensibility changes that might be an indicator for an increased risk of rupture, cross-sectional area changes of abdominal aortic aneurysms (AAA) have been determined using ECG-gated CT.

Materials and methods

Distensibility measurements of the aorta were performed in 67 patients with AAA. Time-resolved images were acquired with a four detector-row CT system using a modified CT-angiography protocol. Pulsatility-related cross-sectional area changes were calculated above and at AAA level by semiautomatic segmentation; distensibility values were obtained using additional systemic blood pressure measurements. Values were compared for small Ø< 5 cm (n=44) and large Ø> 5 cm (n?=?23) aneurysms.

Results

The aorta could be segmented successfully in all patients. Upstream AAA distensibility D was significantly higher than at AAA level for both groups: means above AAA (at AAA) D _above = (1.3±0.8)·10^?5 Pa^?1 (D _AAA = (0.6±0.5)·10^?5 Pa^?1) t-test p_D<0.0001. Differences of the distensibility between smaller and larger aneurysms were not found to be significant.

Conclusion

Distensibility can be measured non-invasively with ECG-gated CT. The reduction of distensibility within aneurysms compared to normal proximal aorta is subtle; the lack of difference between both small and large aneurysms suggests that this reduction occurs early in the aneurysm's development. Hence, reduced distensibility might be a predictive parameter in patients with high risk of aortic disease.

     

Cerebrospinal fluid rhinorrhea: Diagnostic role of gadolinium enhanced MR cisternography

Background

Accurate localization of the defect is crucial for successful surgical repair of CSF rhinorrhea. This could be achieved by MRI cisternography using T1 weighted sequences followed by intra-thecal injection of low dose of gadolinium for valuable localization and characterization of the defect.

Aim

The aim of this study was to evaluate the role of intrathecal gadolinium enhanced MR cisternography in localization of the defect in cases of CSF rhinorrhea to demonstrate how to utilize it as a roadmap to select the most appropriate approach for leak repair.

Patients and methods

This study included 24 patients (16 male and 8 females) with CSF rhinorrhea, referred from Otorhinolaryngology Department. Seventeen leaks were spontaneous, 5 cases were traumatic and two iatrogenic. All cases underwent MR gadolinium enhanced cisternography via lumbar puncture.

Results

Gadolinium enhanced MR cisternography accurately diagnosed and confirmed the site of CSF leak in 22/24 (91.7%) cases. The most common site was the ethmoidal roof in 18/24 cases. Our results were correlated with endoscopic surgery and repair with an accuracy rate of 100%.

Conclusions

Intra-thecal gadolinium enhanced MR cisternography is essential for accurate pre-operative localization and characterization of the defect in cases of CSF rhinorrhea.     

Financial Impact of PEVAR Compared With Standard Endovascular Repair in Canadian Hospitals

Objectives

The percutaneous endovascular abdominal aortic repair (PEVAR) approach is a minimally invasive technique that has demonstrated clinical benefit over traditional surgical cut down associated with standard endovascular abdominal aortic aneurysm (AAA) repair (EVAR). The objective of our study was to evaluate the budget impact to a Canadian hospital of changing the technique for AAA repair from the EVAR approach to the PEVAR approach.

Quantitative assessment of the influence of anatomic noise on the detection of subtle lung nodule in digital chest radiography using fractal-feature distance

Purpose

To confirm whether or not the influence of anatomic noise on the detection of nodules in digital chest radiography can be evaluated by the fractal-feature distance.

Materials and methods

We used the square images with and without a simulated nodule which were generated in our previous observer performance study; the simulated nodule was located on the upper margin of a rib, the inside of a rib, the lower margin of a rib, or the central region between two adjoining ribs. For the square chest images, fractal analysis was conducted using the virtual volume method. The fractal-feature distances between the considered and the reference images were calculated using the pseudo-fractal dimension and complexity, and the square images without the simulated nodule were employed as the reference images. We compared the fractal-feature distances with the observer's confidence level regarding the presence of a nodule in plain chest radiograph.

Results

For all square chest images, the relationships between the length of the square boxes and the mean of the virtual volumes were linear on a log–log scale. For all types of the simulated nodules, the fractal-feature distance was the highest for the simulated nodules located on the central region between two adjoining ribs and was the lowest for those located in the inside of a rib. The fractal-feature distance showed a linear relation to an observer's confidence level.

Conclusion

The fractal-feature distance would be useful for evaluating the influence of anatomic noise on the detection of nodules in digital chest radiography.     

Evaluation of the relationship between renal function and renal volume-vascular indices using 3D power Doppler ultrasound

Purpose

To investigate the relationship between renal function and total renal volume-vascular indices using 3D power Doppler ultrasound (3DPDUS).

Materials and methods

One hundred six patients with hypertensive proteinuric nephropathy (HPN) (49 male, 57 female) and 65 healthy controls (32 male, 33 female) were evaluated prospectively using 3DPDUS. Total renal volume (RV), vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated using Virtual Organ Computer-aided Analysis (VOCAL). The estimated glomerular filtration rates (GFRs) of the patients with HPN and the control group were calculated. The patients with HPN were divided into two groups on the basis of GFR, normal (≥90) or reduced (<90). Differences between groups were compared using ANOVA. Correlations between GFR, renal volume and vascular indices were analyzed using Pearson's correlation analysis. Significance was set at p < 0.05.

Results

The mean total RV, VI, FI and VFI values in the reduced GFR, normal GFR and control groups were RV (ml): 234.7, 280.7 and 294.6; VI: 17.6, 27.6 and 46.8; FI: 79.1, 88.7 and 93.9 and VFI: 7.1, 12.7 and 23.8. There were statistically significant differences between the groups (p < 0.001). Total RVs and vascular indices exhibited significant correlations with estimated GFR (r = 0.53–0.59, p < 0.001)

Conclusion

Three-dimensional power Doppler ultrasound is a reliable predictive technique in renal function analysis.     

Accuracy of Right and Left Ventricular Functional Assessment by Short-Axis vs Axial Cine Steady-State Free-Precession Magnetic Resonance Imaging: Intrapatient Correlation With Main Pulmonary Artery and Ascending Aorta Phase-Contrast Flow Measurements

Objective

The left ventricle (LV) is routinely assessed with cardiac magnetic resonance imaging (MRI) by using short-axis orientation; it remains unclear whether the right ventricle (RV) can also be adequately assessed in this orientation or whether dedicated axial orientation is required. We used phase-contrast (PC) flow measurements in the main pulmonary artery (MPA) and the ascending aorta (Aorta) as nonvolumetric standard of reference and compared RV and LV volumes in short-axis and axial orientations.

Methods

A retrospective analysis identified 30 patients with cardiac MRI data sets. Patients underwent MRI (1.5 T or 3 T), with retrospectively gated cine steady-state free-precession in axial and short-axis orientations. PC flow analyses of MPA and Aorta were used as the reference measure of RV and LV output.

Results

There was a high linear correlation between MPA-PC flow and RV–stroke volume (SV) short axis (r = 0.9) and RV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 1.4 mL for RV axial and –2.3 mL for RV–short-axis vs MPA-PC flow. There was a high linear correlation between Aorta-PC flow and LV-SV short-axis (r = 0.9) and LV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 4.8 m for LV short axis and 7.0 mL for LV axial vs Aorta-PC flow. There was no significant difference (P = .6) between short-axis–LV SV and short-axis–RV SV.

Conclusion

No significant impact of the slice acquisition orientation for determination of RV and LV stroke volumes was found. Therefore, cardiac magnetic resonance workflow does not need to be extended by an axial data set for patients without complex cardiac disease for assessment of biventricular function and volumes.