Algorithm-Based Motion Magnification for Video Processing in Urological Laparoscopy

Applying video motion magnification to reveal spontaneous tympanic membrane displacement as an indirect measure of intracranial pressure in patients with brain pathologies

BACKGROUND

The observation of tympanic membrane displacement (TMD) opens up the possibility of indirect intracranial pressure (ICP) estimation. In this study, we applied a phase-based video motion magnification (VMM) algorithm to reveal spontaneous pulse TMD waveforms (spTMD) and compare them with invasively measured ICP in patients with intracranial pathologies.

METHODS

Nine adults (six traumatic brain injury and three aneurysmal subarachnoid haemorrhage; median age 44 (29-53) years admitted to the intensive care unit of Wroclaw Medical University between October 2021 and October 2022 with implanted ICP sensors were included in this retrospective study. Video recordings of the tympanic membrane were performed using a portable otoscope with a video camera and analysed by a custom-written VMM algorithm. ICP was monitored using intraparenchymal sensors and arterial blood pressure (ABP) was measured in the radial arterial lines. ICP, ABP, and spTMD videos were captured simultaneously. The pulse amplitudes of ICP (Amp_ICP), ABP (Amp_ABP) and spTMD (Amp_spTMD) were estimated using fast Fourier transform within the heart rate (HR)-related frequency range.

RESULTS

Amp_spTMD was significantly correlated with mean ICP (rS = 0.73; p = 0.025) and with Amp_ICP (rS = 0.88; p = 0.002). Age was not a significant moderator of this association. There were no significant relationships between Amp_spTMD and either mean ABP, HR, or Amp_ABP.

CONCLUSIONS

The study suggests that Amp_spTMD increases with the increase in mean ICP and Amp_ICP. Estimation of Amp_spTMD using the VMM algorithm has the potential to allow for non-invasive detection of the risk of elevated ICP; however, further investigation in a larger group of patients is required.

Detection of Muscle Tension Dysphonia Using Eulerian Video Magnification: A Pilot Study

OBJECTIVE

To determine whether Eulerian Video Magnification software is useful in diagnosis of muscle tension dysphonia (MTD).

STUDY DESIGN

Prospective.

METHODS

Adult patients scheduled in a tertiary care laryngology practice for evaluation of dysphonia were recruited between November 2016 and March 2017. Demographic and clinical data were extracted from patient charts. Diagnosis of MTD was confirmed with videostroboscopic and physical exam and by a speech-language pathologist. Eighteen MTD patients were video recorded while at rest and with phonation. Five patients without MTD also were analyzed as controls. Videos were analyzed using Eulerian Video Magnification software (Massachusetts Institute of Technology) to assess change in blood flow at the forehead, infrahyoid muscles, and sternocleidomastoid muscles, while using the values of the background wall as a control value.

RESULTS

Patients with MTD demonstrated little change in perfusion to the infrahyoid muscles of the neck while phonating (+1% ± 55%). Control subjects demonstrated an increase in perfusion to the infrahyoid muscles while phonating (+102% ± 164%), with this change being significant when comparing the two groups (P = 0.04, t = 2.189, df = 21). A change in perfusion of 0% or less to infrahyoid muscles was 75% sensitive and 70% specific for diagnosis of MTD. No differences in perfusion were found between other regions assessed. Patient age and gender did not correlate with any change in perfusion between rest and phonation.

CONCLUSION

Our data suggest that Eulerian Video Magnification can be used in the diagnosis of MTD by focusing on the difference in perfusion to the infrahyoid muscles between rest and phonation.