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The results of B-scan ultrasonography in different positions after vitrectomy and gas tamponade.

Park SH, Lee SJ - Korean J Ophthalmol (2007)

Bottom Line: In this prospective study, 23 patients (23 eyes) who had undergone pars plana vitrectomy and gas tamponade were investigated between June 2005 and February 2006.SF(6) (18%) was injected into the vitreous cavity of 15 eyes, and C(3)F(8) (14%) was injected into the vitreous cavity of 8 eyes.The superior retinal attachment status can be evaluated from the summation of B-scan ultrasonography results performed in the right decubitus and left ducubitus positions.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Soonchunhyang University College of Medicine, Seoul, Korea.

ABSTRACT

Purpose: To determine the proper time frame in which to assess retinal attachment status and to evaluate the superior retinal attachment status by performing B-scan ultrasonography in different positions on patients who have undergone pars plana vitrectomy and gas tamoponade.

Methods: In this prospective study, 23 patients (23 eyes) who had undergone pars plana vitrectomy and gas tamponade were investigated between June 2005 and February 2006. SF(6) (18%) was injected into the vitreous cavity of 15 eyes, and C(3)F(8) (14%) was injected into the vitreous cavity of 8 eyes. At postoperative day 1, day 3, week 1, week 2, and week 4, B-scan ultrasonography was performed in the supine, sitting, prone, right decubitus, and left decubitus positions.

Results: The proper time to evaluate the retinal attachment status was three days post-operatively in 10 eyes (66.7%) with SF(6) (18%) injections and two weeks post-operatively in six eyes (75%) that had C(3)F(8) (14%) injections. The superior retinal attachment status can be evaluated from the summation of B-scan ultrasonography results performed in the right decubitus and left ducubitus positions.

Conclusions: The proper time to evaluate the retinal attachment status was related to the degree of the gas absorption when performing B-scan ultrasonography after pars plana vitrectomy and gas tamponade. To evaluate the entire retina, it is useful to perform B-scan ultrasonograhy in the prone, right decubitus and left decubitus positions.

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The false images on B-scan ultrasonography on the eyes filled with gas. (A) Posterior shadowing (red arrow). (B) Multiple reverberations (blue arrows).
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Figure 8: The false images on B-scan ultrasonography on the eyes filled with gas. (A) Posterior shadowing (red arrow). (B) Multiple reverberations (blue arrows).

Mentions: The reflection coefficient is due to the difference of acoustic impedence in the interface of two materials.10 The general reflection coefficient in the intraocular interface is 0.1-7.0%. However, the reflection coefficient of the gas-liquid interface and the gas-tissue interface is 99.9%, regardless of the type of gas.10 Because of this, the image of the posterior area of gas within the eye could not be assessed by B-scan ultrasonography, and the images produced in that area may be considered to be pseudoimages. In our study, when B-scan ultrasonography was performed in the prone position, images were shown to be similar to the retina. However, by differentiating using the points generated from consecutive tests taken one day apart, it was possible to confirm that they were in fact pseudoimages reflecting from the gas-liquid interface, or mirror images. The images also became larger with time and varied depending on the position of the patient (Fig. 7).10 In addition, posterior shadowing11 or reverberation10 could be observed as pseudoimages when gas was present in the eye (Fig. 8).


The results of B-scan ultrasonography in different positions after vitrectomy and gas tamponade.

Park SH, Lee SJ - Korean J Ophthalmol (2007)

The false images on B-scan ultrasonography on the eyes filled with gas. (A) Posterior shadowing (red arrow). (B) Multiple reverberations (blue arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2629703&req=5

Figure 8: The false images on B-scan ultrasonography on the eyes filled with gas. (A) Posterior shadowing (red arrow). (B) Multiple reverberations (blue arrows).
Mentions: The reflection coefficient is due to the difference of acoustic impedence in the interface of two materials.10 The general reflection coefficient in the intraocular interface is 0.1-7.0%. However, the reflection coefficient of the gas-liquid interface and the gas-tissue interface is 99.9%, regardless of the type of gas.10 Because of this, the image of the posterior area of gas within the eye could not be assessed by B-scan ultrasonography, and the images produced in that area may be considered to be pseudoimages. In our study, when B-scan ultrasonography was performed in the prone position, images were shown to be similar to the retina. However, by differentiating using the points generated from consecutive tests taken one day apart, it was possible to confirm that they were in fact pseudoimages reflecting from the gas-liquid interface, or mirror images. The images also became larger with time and varied depending on the position of the patient (Fig. 7).10 In addition, posterior shadowing11 or reverberation10 could be observed as pseudoimages when gas was present in the eye (Fig. 8).

Bottom Line: In this prospective study, 23 patients (23 eyes) who had undergone pars plana vitrectomy and gas tamponade were investigated between June 2005 and February 2006.SF(6) (18%) was injected into the vitreous cavity of 15 eyes, and C(3)F(8) (14%) was injected into the vitreous cavity of 8 eyes.The superior retinal attachment status can be evaluated from the summation of B-scan ultrasonography results performed in the right decubitus and left ducubitus positions.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Soonchunhyang University College of Medicine, Seoul, Korea.

ABSTRACT

Purpose: To determine the proper time frame in which to assess retinal attachment status and to evaluate the superior retinal attachment status by performing B-scan ultrasonography in different positions on patients who have undergone pars plana vitrectomy and gas tamoponade.

Methods: In this prospective study, 23 patients (23 eyes) who had undergone pars plana vitrectomy and gas tamponade were investigated between June 2005 and February 2006. SF(6) (18%) was injected into the vitreous cavity of 15 eyes, and C(3)F(8) (14%) was injected into the vitreous cavity of 8 eyes. At postoperative day 1, day 3, week 1, week 2, and week 4, B-scan ultrasonography was performed in the supine, sitting, prone, right decubitus, and left decubitus positions.

Results: The proper time to evaluate the retinal attachment status was three days post-operatively in 10 eyes (66.7%) with SF(6) (18%) injections and two weeks post-operatively in six eyes (75%) that had C(3)F(8) (14%) injections. The superior retinal attachment status can be evaluated from the summation of B-scan ultrasonography results performed in the right decubitus and left ducubitus positions.

Conclusions: The proper time to evaluate the retinal attachment status was related to the degree of the gas absorption when performing B-scan ultrasonography after pars plana vitrectomy and gas tamponade. To evaluate the entire retina, it is useful to perform B-scan ultrasonograhy in the prone, right decubitus and left decubitus positions.

Show MeSH
Related in: MedlinePlus