The reproducibility of 20-min time-trial performance on a virtual cycling platform

This study aimed to analyse the reproducibility of mean power output during 20-min cycling time-trials, in a remote home-based setting, using the virtual-reality cycling software, Zwift. Forty-four cyclists (11 women, 33 men; 37 ± 8 years old, 180 ± 8 cm, 80.1 ± 13.2 kg) performed 3 x 20-min time-trials on Zwift, using their own setup. Intra-class correlation coefficient (ICC), coefficient of variation (CV) and typical error (TE) were calculated for the overall sample, split into 4 performance groups based on mean relative power output (25% quartiles) and sex. Mean ICC, TE and CV of mean power output between time-trials were 0.97 [0.95-0.98], 9.36 W [8.02-11.28 W], and 3.7% [3.2-4.5], respectively. Women and men had similar outcomes (ICC: 0.96 [0.89-0.99] vs 0.96 [0.92-0.98]; TE: 8.30 W [6.25-13.10] vs. 9.72 W [8.20-12.23]; CV: 3.8% [2.9-6.1] vs. 3.7% [3.1-4.7], respectively), although cyclists from the first quartile showed a lower CV in comparison to the overall sample (Q1: 2.6% [1.9-4.1] vs. overall: 3.7% [3.2-4.5]). Our results indicate that power output during 20-minute cycling time-trials on Zwift are reproducible and provide sports scientists, coaches and athletes, benchmark values for future interventions in a virtual-reality environment.

P171 Catastrophic systemic multiple embolism from a giant atrial mixoma: a case report

Atrial mixoma represents the most common cardiac tumour. The diagnosis is usually accidental since it is benign and usually asymptomatic. Nevertheless, life-threathening complications such as embolization may seldom occur. In these cases emergent multispecialistic approach is deemed. We describe the case of a 46 year old man without cardiovascular risk factors and whose previous clinical history was not significant. At home, the patient abruptly presented a right hemiplegia, deviation of the buccal commissure to the left and loss of consciousness. On arrival at the emergency department GCS was 5. Routine blood tests, gas analysis and ECG were unremarkable. An urgent CT scan showed a left fronto-parietal subarachnoid hemmorhage. Soon after admission in the stroke unit the patient showed sign of acute limb ischaemia. A high-resolution 3D-angio CT revealed multiple bilateral renal and splenic infarcts and a massive thrombosis of the abdominal aorta below the renal bifurcation, with extensive involvement of the iliac arteries. Unexpectedly, a bulky mass (max diameter 8 cm) was detected in the left atrium. Transthoracic echocardiography confirmed the presence of an irregularly oval (8x3cm) mobile peduncolate mass with fringed edges, suspected for mixoma, with phasic impingement of the mitral valve and protrusion into the left ventricle. Considering the age of the patient and the very early presentation, after Heart Team discussion the patient underwent an urgent embolectomy with Fogarty catheter followed by cardiac surgery for myxoma resection. After full sternotomy, with an interatrial groove approach, a large tumor with myxoid appearance implanted in the left atrial roof was discovered (8 cm maximum diameter). A complete excision of the mass was successfully performed. The macroscopic examination revealed a tumor with a gelatinous and friable surface, very irregular edges and narrow base of implantation, suggestive of atrial myxoma. The day after a CT revealed multiple new ischemic and hemorragic lesions in the left frontal and parietal lobes, in the right occipital lobes, in the cerebellar emispheres, thalamus and hypotalamus and in the mesencephalus. Multiple thrombosis of the main branches of the Willis polygon were detected as well.

The patient remained comatous (GCS 3) with bilateral midriasis and was intubated in the intensive care unit. The anatomopathological study confirmed the diagnosis of atrial myxoma. Despite the general belief that atrial mixoma present a benign course, clinicians should carefully consider the possibility of dramatic complications, due to the risk of embolization. High resolution imaging techniques are of pivotal relevance for the diagnosis of the tumor and the complications, in which case emergent surgery may be required. Early surgery could be considered in asymptomatic patients because the evolutionary course and the prognosis can unexpectedly be ominous.

Abstract P171 Figure. Multiple embolism from atrial myxoma

P640 Multimodality imaging of an asymptomatic aortic fibroelastoma successfully treated with a surgical valve-sparing technique

Papillary fibroelastoma is an uncommon cardiac tumour. It is usually attached to the chordae tendineae or to the papillary muscles, while the involvement of the valves or the LVOT is rarely seen. The diagnosis is often due to incidental finding because the tumor is often asymptomatic, even though structural cardiac damages or dramatic embolization may occur. We present the case of a 66 year old woman affected by arterial hypertension and dyslipidemia. During a routine cardiologic visit a transthoracic echocardiogram unexpectedly revealed the presence of a extremely mobile peduncolate mass (11x5mm) with a homogenous speckle pattern, apparently settled on the aortic side of the right cusp of the aortic valve. No further pathological elements were detected. A diagnosis of suspected fibroelastoma was made and the patient was transferred to the cardiac surgery department. On admission clinical examination and vital signs were unremarkable. No symptoms suggestive of TIA or amaurosis were reported by the patient, hence the tumor was considered as an asymptomatic incidental finding. Since the mass did not seem to be firmly attached, based on the high risk of embolization and the possibility of coronary ostia impingement with the manipulation of the catheters, the Heart Team decided to omit a pre-interventional coronary angiography. A coronary CT scan excluded significant coronary artery disease and the patient was offered a surgical resection of the mass. After anterior mini-sternotomy, during extracorporeal circulation, the ascending aorta was opened with a transversal incision and the aortic valve was exposed. A pedunculated tumour of 1.5x2 cm implanted in the edge of the right cusp was observed and completely excised with a valve-sparing resection. Macroscopically, the tumour looked whitish and filamentous, suggestive of fibroelastoma. At the end of the procedure transesophageal echocardiography guaranteed the competence of the aortic valve was preserved. The patient recovered successfully and was discharged one week after the intervention. The control transthoracic echocardiography excluded tumoral residual and the histological examination confirmed the diagnosis of fibroelastoma. The patient was discharged after an uneventful course. This report singularly shows a rare case of aortic location of an asymptomatic fibroelastoma treated with an early surgical approach in order to avoid embolic complications. Multimodality imaging provides clear and exemplary information about this rare entity. Nowadays, the optimal management of challenging cases requires a multidisciplinary team with a discrete familiarity with the common imaging techniques, which play a pivotal role in the diagnostic, pre-procedural and interventional setting.

Abstract P640 Figure. Multimodality imaging: fibroelastoma

Temporal and Spatial Variances in Arterial Spin-Labeling Are Inversely Related to Large-Artery Blood Velocity

BACKGROUND AND PURPOSE

The relationship between extracranial large-artery characteristics and arterial spin-labeling MR imaging may influence the quality of arterial spin-labeling-CBF images for older adults with and without vascular pathology. We hypothesized that extracranial arterial blood velocity can explain between-person differences in arterial spin-labeling data systematically across clinical populations.

MATERIALS AND METHODS

We performed consecutive pseudocontinuous arterial spin-labeling and phase-contrast MR imaging on 82 individuals (20-88 years of age, 50% women), including healthy young adults, healthy older adults, and older adults with cerebral small vessel disease or chronic stroke infarcts. We examined associations between extracranial phase-contrast hemodynamics and intracranial arterial spin-labeling characteristics, which were defined by labeling efficiency, temporal signal-to-noise ratio, and spatial coefficient of variation.

RESULTS

Large-artery blood velocity was inversely associated with labeling efficiency (P = .007), temporal SNR (P < .001), and spatial coefficient of variation (P = .05) of arterial spin-labeling, after accounting for age, sex, and group. Correction for labeling efficiency on an individual basis led to additional group differences in GM-CBF compared to correction using a constant labeling efficiency.

CONCLUSIONS

Between-subject arterial spin-labeling variance was partially explained by extracranial velocity but not cross-sectional area. Choosing arterial spin-labeling timing parameters with on-line knowledge of blood velocity may improve CBF quantification.

Traumatic transdural spinal cord herniation and the nuclear trail sign: case report

A woman with a history of spine injury in her remote past developed Brown-Sequard syndrome due to a thoracic transdural spinal cord herniation. A clue about the underlying mechanism was offered by the unexpected imaging feature of a nuclear trail sign just below the herniated cord. As suggested by Watters et al., who reported a similar case, this finding is consistent with the hypothesis that intrathecal rupture of disk material could have resulted in an acquired tear of the ventral dural, through which the cord herniated.