From 2-dimensional cephalograms to 3-dimensional computed tomography scans

Abstract BACKGROUND: A standard pterional approach with a free bone flap to treat brain aneurysms was first introduced and popularized by Yaşargil. OBJECTIVE: To describe a modified pterional craniotomy technique and that mobilizes part of the sphenoid wing and the pterion in a block with the temporalis muscle to enhance cosmetic results. METHODS: A subperiosteal corridor is provided inferiorly by separating the temporalis muscle from the underlying bone in a retrograde dissection. Inferior chisel cuts from the front and back enter the sphenoid wing, enabling removal of part of the sphenoid wing and the pterion in 1 piece, along with the bone flap. Forty patients with aneurysms were treated in this fashion, and the cosmetic outcome was examined at 6 months postoperatively. RESULTS: Thirty-seven patients (92.5%) demonstrated an unremarkable degree of temporalis muscle atrophy. Excellent configuration and fusion of the pterional bone flap were observed on 3-dimensional computed tomography scans. CONCLUSION: With the use of this muscle-preserving and bone-sparing pterional approach and with little additional labor, temporalis muscle function is preserved and improved cosmesis is obtained.

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PO 18235 - New tomographic method for measuring metatarsal rotation in hallux valgus

Scientific Journal of the Foot & Ankle ◽

10.30795/scijfootankle.2019.v13.1047 ◽

2019 ◽

Vol 13 (Supl 1) ◽

pp. 52S

Author(s):

Bruno Rodrigues de Miranda ◽

Rui Dos Santos Barroco ◽

Leticia Zaccaria Prates de Oliveira ◽

Mahmoud Beerens Abdul Ghani Abdul Ghani ◽

Antonio Candido de Paula Neto ◽

...

Keyword(s):

Computed Tomography ◽

Hallux Valgus ◽

Weight Bearing ◽

Alpha Angle ◽

Metatarsal Bone ◽

3 Dimensional ◽

First Metatarsal ◽

Computed Tomography Scans ◽

Tomographic Method ◽

The Relationship

Introduction: Hallux valgus is a 3-dimensional deformity involving an increased intermetatarsal I/II angle and a rotational deformity of the first metatarsal bone. Kim et al. developed a method for measuring the tibial sesamoid position relative to the coronal rotation of the first metatarsal bone in computed tomography scans under simulated weight-bearing conditions. Objective: To describe a method for the topographic assessment of the correction of tibial sesamoid and metatarsal pronation using computed tomography scans under simulated weight-bearing and active toe extension. Method: We performed computed tomography under simulated weight-bearing conditions with and without active toe dorsiflexion, observing the degree of metatarsal pronation and sesamoid subluxation. For measurement purposes, we used the classifications of Kim et al. and Smith et al. Results: We observed tomographic correction, both angular and rotational, by measuring the intermetatarsal angle and tibial sesamoid position, which were confirmed by the change in the alpha angle suggested by Kim et al. Discussion: Toe extension was described as a peroneus longus tendon activation test by Klemola et al., who used this maneuver to demonstrate clinical rotational correction of hallux valgus. We described the use of a tomographic technique that followed this principle to preoperatively observe the underlying factors that may affect the rotational correction of the deformity. Conclusion: The method has the capacity for correction in various planes involving derotation of the first metatarsal bone and the relationship between such derotation and the change in sesamoid position in relation to the coronal plane of the foot.

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Accuracy and Reliability of a Simple Calculation for Measuring Glenoid Bone Loss on 3-Dimensional Computed Tomography Scans

Arthroscopy The Journal of Arthroscopic and Related Surgery ◽

10.1016/j.arthro.2017.07.032 ◽

2018 ◽

Vol 34 (1) ◽

pp. 84-92 ◽

Cited By ~ 15

Author(s):

Stephen A. Parada ◽

Josef K. Eichinger ◽

Guillaume D. Dumont ◽

Carrie A. Parada ◽

Alyssa R. Greenhouse ◽

...

Keyword(s):

Computed Tomography ◽

Bone Loss ◽

Simple Calculation ◽

Glenoid Bone Loss ◽

3 Dimensional ◽

Computed Tomography Scans

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Reproducibility of a Noninvasive System for Eye Positioning and Monitoring in Stereotactic Radiotherapy of Ocular Melanoma

Technology in Cancer Research & Treatment ◽

10.1177/1533034617690979 ◽

2017 ◽

Vol 16 (3) ◽

pp. 352-356 ◽

Cited By ~ 1

Author(s):

Omar Iskanderani ◽

Dominique Béliveau-Nadeau ◽

Robert Doucet ◽

Geneviève Coulombe ◽

Deborah Pascale ◽

...

Keyword(s):

Computed Tomography ◽

Optic Nerve ◽

Stereotactic Radiotherapy ◽

Choroidal Melanoma ◽

Target Volume ◽

Visual Monitoring ◽

3 Dimensional ◽

Computed Tomography Scans ◽

Visual Monitoring System ◽

Anterior Posterior

Purpose: Our preferred treatment for juxtapapillary choroidal melanoma is stereotactic radiotherapy. We aim to describe our immobilization system and quantify its reproducibility. Materials and Methods: Patients were identified in our radiosurgery database. Patients were imaged at computed tomography simulator with an in-house system which allows visual monitoring of the eye as the patient fixates a small target. All patients were reimaged at least once prior to and/or during radiotherapy. The patients were treated on the CyberKnife system, 60 Gy in 10 daily fractions, using skull tracking in conjunction with our visual monitoring system. In order to quantify the reproducibility of the eye immobilization system, computed tomography scans were coregistered using rigid 6-dimensional skull registration. Using the coregistered scans, x, y, and z displacements of the lens/optic nerve insertion were measured. From these displacements, 3-dimensional vectors were calculated. Results: Thirty-four patients were treated from October 2010 to September 2015. Thirty-nine coregistrations were performed using 73 scans (2-3 scans per patient). The mean displacements of lens and optic nerve insertion were 0.1 and 0.0 mm. The median 3-dimensional displacements (absolute value) of lens and nerve insertion were 0.8 and 0.7 mm (standard deviation: 0.5 and 0.6 mm). Ninety-eight percent of 3-dimensional displacements were below 2 mm (maximum 2.4 mm). The calculated planning target volume (PTV) margins were 0.8, 1.4, and 1.5 mm in the anterior–posterior, craniocaudal, and right–left axes, respectively. Following this analysis, no further changes have been applied to our planning margin of 2 to 2.5 mm as it is also meant to account for uncertainties in magnetic resonance imaging to computed tomography registration, skull tracking, and also contouring variability. Conclusion: We have found our stereotactic eye immobilization system to be highly reproducible (<1 mm) and free of systematic error.

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