Quantitative analysis of brain edema and swelling on early postmortem computed tomography: comparison with antemortem computed tomography

Purpose

The aim of this study was quantitatively to analyze brain edema and swelling due to early postmortem changes using computed tomography (CT) scans of the head.

Materials and methods

Review board approval was obtained, and informed consent was waived. A total of 41 patients who underwent head CT before and shortly after death were enrolled. Hounsfield units (HUs) of gray matter (GM) and white matter (WM) were measured at the levels of the basal ganglia, centrum semiovale, and high convexity area on both antemortem and postmortem CT. The length of the minor axis of the third ventricle at the level of the basal ganglia and the width of the central sulcus at the level of high convexity were measured.

Results

At each level tested, the HUs of GM and the GM/WM ratios on postmortem CT were significantly lower than those on antemortem CT (P < 0.001). HUs of WM on postmortem CT were slightly higher than those on antemortem CT but without significant difference (P > 0.1). Postmortem CT showed subtle loss of distinction between GM and WM. The size of the third ventricle and the width of the central sulcus did not vary before and after death (P > 0.1).

Conclusion

Early postmortem CT shows mild brain edema but does not show brain swelling.     

Vascular measurement changes observed using postmortem computed tomography

Purpose

Postmortem vascular changes were quantitatively analyzed in the aorta and vena cava and compared with antemortem findings as a basis for distinguishing between normal postmortem changes and pathological changes.

Materials and methods

Whole-body computed tomography (CT) was performed on 12 individuals before and after death. The scans, performed at seven levels (five for the aorta, two for the vena cava) within the vasculature, allowed various measurements to be made on the same individual before and after death.

Results

Postmortem long-axis diameter, short-axis diameter, and the square of the radius of the aorta were 79.2–85.0 % (mean 81.3 %), 55.6–80.0 % (68.0 %), and 48.5–71.4 % (60.8 %) of the antemortem measurements, respectively. The ante- and postmortem measurements of the long and short axes and the caliber of the aorta were statistically different (p < 0.05). The superior vena cava (SVC) was increased in size: the short-axis diameter and the square of the radius were both statistically different after death. None of the measured parameters of the inferior vena cava (IVC) changed significantly following death.

Conclusion

In postmortem images, the aortic diameter decreased and changes in the size and shape of the SVC were noted. The IVC did not exhibit significant postmortem changes.     

Postmortem lung features in drowning cases on computed tomography

Purpose

We sought to compare postmortem chest computed tomography (CT) features of drowning cases with autopsy findings, and to classify these features.

Materials and method

We performed a retrospective analysis of high-resolution and multi-planar reconstruction chest CT images of drowning in 92 adults (54 men, 38 women; mean age 65.4 years) scanned before forensic autopsy. The average lung CT number was calculated from whole-lung images reconstructed on a 3D workstation. The statistically significant differences of CT numbers were assessed with an alpha level of 0.05.

Results

Postmortem chest CT image patterns were classified into six types: the two main types were ground-glass opacities with thickened pulmonary interstitium (n = 31), and a centrilobular distribution of ill-defined nodules along the airways (n = 38). Some cases were mixed type (n = 10). There were significant differences in CT numbers between each type. The remaining three types were consolidation (n = 5), emphysema and/or fibrosis (n = 4), and unclassifiable (n = 4).

Conclusion

Postmortem CT images of drowning cases can be classified into three major types with a few exceptions.     

Postmortem changes of the thyroid on computed tomography

Objective

To evaluate the radiographic features of the thyroid on postmortem computed tomography (PMCT).

Methods

We studied the bodies of 32 subjects who had been treated and subsequently died in our tertiary care hospital between April and December 2009. The thyroids were imaged by antemortem computed tomography (AMCT), PMCT, and examined by conventional autopsy. Differences between the radiographic features of the thyroid on AMCT and PMCT, and time since AMCT were evaluated statistically.

Results

CT values of the thyroid decreased after death with an average of 114.2 Hounsfield Units (HUs) on AMCT vs. 107.7 HU on PMCT (paired t-test, P = 0.023). There was no correlation between the elapsed time from AMCT and differences of CT values of the thyroid on AMCT and PMCT (Spearman’s rank correlation test, P > 0.05).

Conclusion

We showed that CT values of the thyroid decreased after death.     

ECG-gated computed tomography: a new role for patients with suspected aortic prosthetic valve endocarditis

Objectives

The aim of this prospective study was to investigate the agreement in findings between ECG-gated CT and transoesophageal echocardiography (TEE) in patients with aortic prosthetic valve endocarditis (PVE).

Methods

Twenty-seven consecutive patients with PVE underwent 64-slice ECG-gated CT and TEE and the results were compared. Imaging was compared with surgical findings (surgery was performed in 16 patients).

Results

TEE suggested the presence of PVE in all patients [thickened aortic wall (n?=?17), vegetation (n?=?13), abscess (n?=?16), valvular dehiscence (n?=?10)]. ECG-gated CT was positive in 25 patients (93?%) [thickened aortic wall (n?=?19), vegetation (n?=?7), abscess (n?=?18), valvular dehiscence (n?=?7)]. The strength of agreement [kappa (95?% CI)] between ECG-gated CT and TEE was very good for thickened wall [0.83 (0.62–1.0)], good for abscess [0.68 (0.40–0.97)] and dehiscence [0.75 (0.48–1.0)], and moderate for vegetation [0.55 (0.26–0.88)]. The agreement was good between surgical findings (abscess, vegetation and dehiscence) and imaging for ECG-gated CT [0.66 (0.49–0.87)] and TEE [0.79 (0.62–0.96)] and very good for the combination of ECG-gated CT and TEE [0.88 (0.74–1.0)].

Conclusion

Our results indicate that ECG-gated CT has comparable diagnostic performance to TEE and may be a valuable complement in the preoperative evaluation of patients with aortic PVE.     

Multi-detector computed tomography is equivalent to trans-oesophageal echocardiography for the assessment of the aortic annulus before transcatheter aortic valve implantation

Objectives

In transcatheter aortic valve implantation (TAVI), assessment of the aortic annulus is mandatory. We sought to investigate the correlation between trans-oesophageal echocardiography (TEE) and multi-detector computed tomography (MDCT) for annulus diameter assessment before TAVI.

Methods

A total of 122 patients (67 male, mean age 84 ± 6?years) underwent MDCT and TEE for TAVI planning. In TEE annulus diameters were obtained in a long-axis view at diastole. MDCT data were evaluated using MPR images, and corresponding projections were adjusted for MDCT and TEE. Patients were classified by the predominant localisation of aortic valve calcifications, and annulus diameters between TEE and MDCT were correlated. Additionally, the eccentricity of the aortic annulus was calculated.

Results

Mean eccentricity of the aortic annulus determined by MDCT was 0.34?±?0.17, with no difference according to valve calcification. Regarding the aortic annulus diameter, the mean values measured were 24.3?±?2.1?mm in MDCT and 24.0?±?2.5?mm in TEE (P?<?0.0001 for agreement).

Conclusions

Independent of the pattern of aortic valve calcification, close correlation is found between CT and TEE measurements of the aortic annulus diameter. In addition, CT demonstrates the non-circular shape of the aortic annulus.

Key Points

? Accurate assessment of aortic annulus before transcatheter aortic valve implantation is crucial. ? Trans-oesophageal echocardiography has been the preferred method for aortic annulus assessment. ? We demonstrated a strong correlation between TEE and CT for annulus dimensions. ? CT reliably demonstrates the non-circular shape of the aortic annulus. ? CT could therefore be generally used for aortic annulus assessment before TAVI.     

Interruption of the aortic arch: diagnosis with multidetector computed tomography

Purpose

We investigated retrospectively the usefulness of multidetector computed tomography (MDCT) in the preoperative diagnosis of interruption of the aortic arch (IAA).

Materials and methods

Seven neonates with IAA underwent enhanced MDCT before a surgical repair operation between April 2006 and March 2010. The MDCT procedures were performed using either a 16- or 64-MDCT scanner without electrocardiographic gating or respiratory arrest.

Results

High-quality CT images were obtained in all cases. One patient was diagnosed to be IAA type A, and 6 were diagnosed to be IAA type B (Celoria and Patton classification). The Celoria and Patton classification of IAA types and subtype classification by MDCT were confirmed by surgery.

Conclusion

Our results show that the information from MDCT was sufficient for a preoperative diagnosis of IAA and allowed omission of a cardiac catheter examination before surgery.     

Three-dimensional pelvimetry by computed tomography

Purpose

This study was undertaken to assess the agreement of computed tomography (CT) pelvimetry with different postprocessing techniques.

Materials and methods

CT data sets of 25 patients were retrospectively analysed. There were no CT examinations performed solely for pelvimetry, and there was no radiation exposure for study purposes. Six pelvimetric measurements were obtained by two independent observers in four data sets of each patient, i.e. on biplanar topograms, multiplanar reconstructions of 1-mm slices, volume-rendered images of the same data and volume-rendered images based on 5-mm-thick images. Interobserver agreement and variability were determined by Bland-Altman analysis. A human skeleton was also scanned and measured with the same techniques and by ruler as reference.

Results

With a correlation coefficient of 0.98, interobserver agreement was best for assessing 3D volume-rendered images reconstructed from 1-mm-thick slices. Interobserver variability was very good for sagittal outlet and midpelvic diameter, transverse inlet diameter and obstetric conjugate (correlation coefficients 0.96–0.99) but limited for intertuberous and interspinous distance. CT and ruler measurements of the skeleton showed excellent agreement.

Conclusions

Pelvimetry can be obtained with low interobserver variability on 3D volume-rendered CT reconstructions. Thus, CT pelvimetry is suitable to gain exact knowledge of pelvic anatomy to identify relevant parameters for dystocia in retrospective studies.     

Post-mortem computed tomography compared to forensic autopsy findings: a French experience

Objectives

The principal aim of our study was to establish concordance between post-mortem CT (PMCT) and forensic standard autopsy (SA) in detecting lesions according to different anatomical regions. A secondary aim was to determine the efficacy of PMCT in showing lethal lesions.

Methods

PMCTs were compared with autopsies in 236 cadavers in different contexts of death. PMCT findings were assessed by two independent radiologists.

Results

Concordance between PMCT and autopsy was almost perfect in showing skull, basal skull and hyoid bone fractures as well as in detecting facial, vertebral or pelvic fractures. Both examinations were discordant in demonstrating some intracranial injuries, vascular or organ wounds (more findings showed by autopsy), as well in showing free air in anatomical cavities (more findings detected by PMCT). Moreover, PMCT was effective in determining lethal lesions in the context of craniofacial trauma or after a gunshot wound. Concordance between the findings of the two radiologists was almost perfect for each type of lesion.

Conclusion

PMCT could be considered as effective as SA in determining the cause of death in certain traumatic events. It was also effective in showing lethal lesions and could be a useful tool in reducing the number of SA.

Key Points

? Post-mortem CT is increasingly performed as an alternative/adjunct to formal autopsy. ? More modern CT systems provide greater anatomical scope. ? PMCT can usually determine the cause of most deaths following trauma. ? Prospective studies are still required to establish an algorithm for forensic CT.     

Virtual autopsy using multislice computed tomography in forensic medical diagnosis of drowning

Purpose

This study evaluated the usefulness of multidetector computed tomography (MDCT) in the postmortem diagnosis of death by drowning in fresh water by measuring the difference of blood density within the cardiac chambers.

Materials and methods

Twenty-two corpses including six cases of fresh-water drowning (group A) and 16 deaths by other causes (group B), among which were also different forms of mechanical asphyxia other than drowning, underwent MDCT and conventional autopsy. Blood density within the right and left heart chambers, the aorta and the pulmonary trunk was measured and values compared between groups and within each group between heart chambers.

Results

Blood density in all cardiac chambers was lower in group A than in group B. The difference was statistically significant within the left atrium and ventricle and was significantly lower in the left than in the right heart chambers in group A only.

Conclusions

MDCT, together with conventional autopsy, may contribute to the diagnosis of drowning, by measuring blood density in the heart chambers.     

Postmortem computed tomography angiography vs. conventional autopsy: advantages and inconveniences of each method

Purpose

Postmortem computed tomography angiography (PMCTA) was introduced into forensic investigations a few years ago. It provides reliable images that can be consulted at any time. Conventional autopsy remains the reference standard for defining the cause of death, but provides only limited possibility of a second examination. This study compares these two procedures and discusses findings that can be detected exclusively using each method.

Materials and methods

This retrospective study compared radiological reports from PMCTA to reports from conventional autopsy for 50 forensic autopsy cases. Reported findings from autopsy and PMCTA were extracted and compared to each other. PMCTA was performed using a modified heart–lung machine and the oily contrast agent Angiofil® (Fumedica AG, Muri, Switzerland).

Results

PMCTA and conventional autopsy would have drawn similar conclusions regarding causes of death. Nearly 60 % of all findings were visualized with both techniques. PMCTA demonstrates a higher sensitivity for identifying skeletal and vascular lesions. However, vascular occlusions due to postmortem blood clots could be falsely assumed to be vascular lesions. In contrast, conventional autopsy does not detect all bone fractures or the exact source of bleeding. Conventional autopsy provides important information about organ morphology and remains the only way to diagnose a vital vascular occlusion with certitude.

Conclusion

Overall, PMCTA and conventional autopsy provide comparable findings. However, each technique presents advantages and disadvantages for detecting specific findings. To correctly interpret findings and clearly define the indications for PMCTA, these differences must be understood.     

Appearance of gas collections after scuba diving death: a computed tomography study in a porcine model

Introduction

Postmortem computed tomography can easily demonstrate gas collections after diving accidents. Thus, it is often used to support the diagnosis of air embolism secondary to barotrauma. However, many other phenomenons (putrefaction, resuscitation maneuvers, and postmortem tissue offgassing) can also cause postmortem gas effusions and lead to a wrong diagnosis of barotrauma.

Objectives

The aim of this study is to determine topography and time of onset of postmortem gas collections respectively due to putrefaction, resuscitation maneuvers, and tissue offgassing.

Materials and methods

A controlled experimental study was conducted on nine pigs. Three groups of three pigs were studied postmortem by CT from H0 to H24: one control group of nonresuscitated nondivers, one group of divers exposed premortem to an absolute maximal pressure of 5 b for 16 min followed by decompression procedures, and one group of nondivers resuscitated by manual ventilation and thoracic compression for 20 min. The study of intravascular gas was conducted using CT scan and correlated with the results of the autopsy.

Results

The CT scan reveals that, starting 3 h after death, a substantial amount of gas is observed in the venous and arterial systems in the group of divers. Arterial gas appears 24 h after death for the resuscitated group and is absent for the first 24 h for the control group. Concerning the putrefaction gas, this provokes intravenous and portal gas collections starting 6 h after death. Subcutaneous emphysema was observed in two of the three animals from the resuscitated group, corresponding to the thoracic compression areas.

Conclusion

In fatal scuba diving accidents, offgassing appears early (starting from the first hour after death) in the venous system then spreads to the arterial system after about 3 h. The presence of intra-arterial gas is therefore not specific to barotrauma. To affirm a death by barotrauma followed by a gas embolism, a postmortem scanner should be conducted very early. Subcutaneous emphysema should not be mistaken as diagnostic criteria of barotrauma because it can be caused by the resuscitation maneuvers.     

Impact of contrast injection and stent-graft implantation on reproducibility of volume measurements in semiautomated segmentation of abdominal aortic aneurysm on computed tomography

Purpose

To assess the impact of contrast injection and stent-graft implantation on feasibility, accuracy, and reproducibility of abdominal aortic aneurysm (AAA) volume and maximal diameter (D-max) measurements using segmentation software.

Materials and methods

CT images of 80 subjects presenting AAA were divided into four equal groups: with or without contrast enhancement, and with or without stent-graft implantation. Semiautomated software was used to segment the aortic wall, once by an expert and twice by three readers. Volume and D-max reproducibility was estimated by intraclass correlation coefficients (ICC), and accuracy was estimated between the expert and the readers by mean relative errors.

Results

All segmentations were technically successful. The mean AAA volume was 167.0?±?82.8 mL and the mean D-max 55.0?±?10.6 mm. Inter- and intraobserver ICCs for volume and D-max measurements were greater than 0.99. Mean relative errors between readers varied between ?1.8?±?4.6 and 0.0?±?3.6 mL. Mean relative errors in volume and D-max measurements between readers showed no significant difference between the four groups (P?≥?0.2).

Conclusion

The feasibility, accuracy, and reproducibility of AAA volume and D-max measurements using segmentation software were not affected by the absence of contrast injection or the presence of stent-graft.

Key points

? AAA volumetry by semiautomated segmentation is accurate on CT following endovascular repair. ? AAA volumetry by semiautomated segmentation is accurate on unenhanced CT. ? Standardization of the segmentation technique maximizes the reproducibility of volume measurements.     

Whole brain analysis of postmortem density changes of grey and white matter on computed tomography by statistical parametric mapping

Objectives

This study examined the usefulness of statistical parametric mapping (SPM) for investigating postmortem changes on brain computed tomography (CT).

Methods

This retrospective study included 128 patients (23???100 years old) without cerebral abnormalities who underwent unenhanced brain CT before and after death. The antemortem CT (AMCT) scans and postmortem CT (PMCT) scans were spatially normalized using our original brain CT template, and postmortem changes of CT values (in Hounsfield units; HU) were analysed by the SPM technique.

Results

Compared with AMCT scans, 58.6 % and 98.4 % of PMCT scans showed loss of the cerebral sulci and an unclear grey matter (GM)–white matter (WM) interface, respectively. SPM analysis revealed a significant decrease in cortical GM density within 70 min after death on PMCT scans, suggesting cytotoxic brain oedema. Furthermore, there was a significant increase in the density of the WM, lenticular nucleus and thalamus more than 120 min after death.

Conclusions

The SPM technique demonstrated typical postmortem changes on brain CT scans, and revealed that the unclear GM–WM interface on early PMCT scans is caused by a rapid decrease in cortical GM density combined with a delayed increase in WM density. SPM may be useful for assessment of whole brain postmortem changes.

Key Points

? The original brain CT template achieved successful normalization of brain morphology.? Postmortem changes in the brain were independent of sex.? Cortical GM density decreased rapidly after death.? WM and deep GM densities increased following cortical GM density change.? SPM could be useful for assessment of whole brain postmortem changes.

     

Congenital anomalies of the left brachiocephalic vein detected in adults on computed tomography

Purpose

Anomalous left brachiocephalic vein (BCV) is a rare and less known systemic venous anomaly. We evaluated congenital anomalies of the left BCV in adults detected during computed tomography (CT) examinations.

Materials and methods

This retrospective study included 81,425 patients without congenital heart disease who underwent chest CT. We reviewed the recorded reports and CT images for congenital anomalies of the left BCV including aberrant and supernumerary BCVs. The associated congenital aortic anomalies were assessed.

Results

Among 73,407 cases at a university hospital, 22 (16 males, 6 females; mean age, 59 years) with aberrant left BCVs were found using keyword research on recorded reports (0.03%). Among 8018 cases at the branch hospital, 5 (4 males, 1 female; mean age, 67 years) with aberrant left BCVs were found using CT image review (0.062%). There were no significant differences in incidences of aberrant left BCV between the two groups. Two cases had double left BCVs. Eleven cases showed high aortic arches. Two cases had the right aortic arch, one case had an incomplete double aortic arch, and one case was associated with coarctation.

Conclusion

Aberrant left BCV on CT examination in adults was extremely rare. Some cases were associated with aortic arch anomalies.

     

Trabecular bone structure parameters from 3D image processing of clinical multi-slice and cone-beam computed tomography data

Objective

Bone strength depends on both mineral content and bone structure. The aim of this in vitro study was to develop a method of quantitatively assessing trabecular bone structure by applying three-dimensional image processing to data acquired with multi-slice and cone-beam computed tomography using micro-computed tomography as a reference.

Materials and Methods

Fifteen bone samples from the radius were examined. After segmentation, quantitative measures of bone volume, trabecular thickness, trabecular separation, trabecular number, trabecular nodes, and trabecular termini were obtained.

Results

The clinical machines overestimated bone volume and trabecular thickness and underestimated trabecular nodes and number, but cone-beam CT to a lesser extent. Parameters obtained from cone beam CT were strongly correlated with μCT, with correlation coefficients between 0.93 and 0.98 for all parameters except trabecular termini.

Conclusions

The high correlation between cone-beam CT and micro-CT suggest the possibility of quantifying and monitoring changes of trabecular bone microarchitecture in vivo using cone beam CT.     

Comparison of acetabular version angle measurements between prone and reformatted supine computed tomography images

Purpose

To compare acetabular version angle measurements of CT scans in the prone and reformatted supine positions. CT acetabular version angle measurements have previously been done in the prone position to correct for pelvic tilt. With the advent of multidetector CT, recent studies have evaluated acetabular version angles measured in the supine position. To our knowledge, a comparison between these two approaches has not been performed.

Study design

Case series in which consecutive CT urography studies of 49 adult patients performed in both prone and supine positions were retrospectively reviewed, and acetabular version angles of both hips measured.

Method

Retrospective review of 49 consecutive CT urography studies performed in both prone and supine positions was done, and acetabular version angles of both hips were measured. Two radiologists measured the acetabular version angles independently. Multiplanar reformation of the supine CT images was performed to compensate for pelvic tilt and rotation prior to angle measurements.

Results

There was excellent interobserver agreement between the two readers (ICC?=?0.90). Acetabular version angle measurements from the prone CT images were larger compared to reformatted supine images (24.0 and 21.3°, respectively, p?<?0.0001), with greater angles found in women. There was strong correlation between supine and prone acetabular version angle measurements with a Pearson correlation coefficient of 0.743.

Conclusions

Acetabular version angles measured from prone and reformatted supine CT images show strong correlation but are significantly different with larger angles obtained from the former and in women; clinical implications of these findings may require further study in other to determine the best method of version angle measurement. CT acetabular version angle measurement is also reliable with excellent interobserver correlation.     

Multidetector computed tomography in the study of pancreatic metastases

Purpose

The aim of this study was to explore the diagnostic performance of multidetector computed tomography (MDCT) in characterising pancreatic metastases.

Materials and methods

CT examinations of 17 patients affected by pancreatic metastases were retrospectively reviewed. The primary malignancy was renal cell carcinoma (RCC) in eight cases, uterine leiomyosarcoma in two, lung carcinoma in four and breast carcinoma in three. CT images were assessed for lesion number, size and morphology.

Results

Pancreatic lesions were solitary in seven cases and multiple in ten. Lesion size ranged between 8 and 40 mm. Metastases from RCC were hyperattenuating in the arterial phase, metastases from breast cancer and lung cancer were hypoattenuating and metastases from uterine leiomyosarcoma were inhomogeneous. Precise lesion characterisation was obtained by using CT examination in 12 cases. In the remaining five patients, all with solitary metastases from RCC, a precise diagnosis was not possible because the lesions could not be differentiated from a neuroendocrine tumour.

Conclusions

MDCT allowed pancreatic metastases characterisation in 70.5% of cases. The lesions were the manifestation of widely disseminated neoplastic disease, with the exception of metastases from RCC, which were exclusively located in the pancreas.     

CT analysis of the aorta in giant-cell arteritis: a case-control study

Objectives

Giant cell arteritis (GCA) is a large-vessel vasculitis whose diagnosis is confirmed by temporal artery biopsy. However, involvement of large vessels, especially the aorta, can be shown by imaging, which plays an increasing role in GCA diagnosis. The threshold above which aortic wall thickening, as measured by computed tomography (CT), is considered pathological is controversial, with values ranging from 2 to 3 mm. This study assessed aortic morphology by CT scan and its diagnostic value in GCA.

Methods

Altogether, 174 patients were included (64 with GCA, 43 with polymyalgia rheumatica and 67 controls). All patients had a CT scan at diagnosis or at inclusion for controls. Aortic wall thickness, aortic diameter and scores for atheroma were measured. Assessor was blinded to each patient’s group.

Results

Aortic diameters and atheroma scores were similar between groups. Aortic wall thickness was greater in the GCA group, even after the exclusion of GCA patients with aortic wall thickness ≥3 mm. The receiver operating characteristic (ROC) curve showed that a wall thickness of 2.2 mm was the optimal threshold to diagnose GCA (sensitivity, 67%; specificity, 98%).

Conclusions

Measuring aortic wall thickness by CT scan is effective to diagnose GCA. The optimal threshold to regard aortic wall thickening as pathological was ≥2.2 mm.

Key points

? Imaging, including CT scan, plays an increasing role in GCA diagnosis? CT measurement of aortic wall thickness is useful to diagnose GCA? A 2.2-mm threshold allows the diagnosis of thickened aortic wall in GCA

     

Reproducibility of aortic annulus measurements by computed tomography

Objectives

To evaluate a systematic approach for measurement of aortic annulus dimensions by cardiac computed tomography.

Methods

CT data sets of 64 patients were evaluated. An oblique cross-section aligned with the aortic root was created by systematically identifying the caudal insertion points of the three aortic cusps and sequentially aligning them in a double oblique plane. Aortic annulus dimensions, distances of coronary ostia and a suitable fluoroscopic projection angle were independently determined by two observers.

Results

Interobserver intraclass correlation coefficients (ICC) for aortic annulus diameters were excellent (ICC 0.89–0.93). Agreement for prosthesis size selection was excellent (??=?0.86 for mean, ??=?0.84 for area-derived and ??=?0.91 for circumference-derived diameter). Mean distances of the left/right coronary ostium were 13.4?±?2.4/14.4?±?2.8 mm for observer 1 and 13.2?±?2.7/13.5?±?3.2 mm for observer 2 (p?=?0.30 and p?=?0.0001, respectively; ICC 0.76/0.77 for left/right coronary artery). A difference of less than 10° for fluoroscopic projection angle was achieved in 84.3 % of patients.

Conclusions

A systematic approach to generate a double oblique imaging plane exactly aligned with the aortic annulus demonstrates high interobserver and intraobserver agreements for derived measurements which are not influenced by aortic root calcification.

Key Points

? Systematic approach to generate a double oblique imaging plane for TAVI evaluation. ? This method is straightforward and software independent. ? An approach with high reproducibility, not influenced by aortic root calcification.