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Seeing with Sound: Diagnostic Ultrasound Imaging
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
As described so far, the B-scan only provides a single line of information about one path. After one pathway has been scanned and plotted, the direction of the ultrasound pulse is changed, and the entire process repeated. Multiple adjacent beam paths are scanned in sequence and the resulting distances and echo intensities are displayed side by side to gradually compile a cross-sectional image. After the full scan is complete, the B-scan will show bright spots that delineate the entire outline of the organ (Figure 4.9b). One can think of the cross-sectional image's relation to the entire body as similar to that of a single slice taken from a loaf of bread. Ultrasound scanners often display only a single “slice” of the body at a time to enable a determination of the dimensions and structure inside organs and other tissues. The exact orientation of the slice depends upon how the transducer is oriented. The plane swept out by the ultrasound pulse is the plane in which the cross-sectional image is generated.
Apparent Sudden Visual Loss: An Essential Approach
Published in Amy-lee Shirodkar, Gwyn Samuel Williams, Bushra Thajudeen, Practical Emergency Ophthalmology Handbook, 2019
B-scan: In cases of no fundal view, whatever the cause, it is imperative to perform B-scan ultrasonography to assess the integrity of the retina. This is a skill that all ophthalmologists in training should acquire. A vitreous haemorrhage for example will appear as a mobile reflective vitreous opacity (see Chapter 11 for further reading).
The crystalline lens
Published in Mary E. Shaw, Agnes Lee, Ophthalmic Nursing, 2018
The ‘B’ Scan is an ultrasound scan used before cataract extractions. It gives a three-dimensional picture of the eye, showing up any abnormality in the media, such as a retinal detachment or tumour. This examination is necessary because the ophthalmologist is unable to examine the fundus through an opaque lens. If a tumour or retinal detachment were noted, the lens extraction might not take place, as no improvement in vision would occur.
Iris Juvenile Xanthogranuloma Presenting with Hypopyon
Published in Ocular Immunology and Inflammation, 2022
Mine Esen Baris, Mukaddes Damla Ciftci, Melis Palamar, Suzan Guven Yilmaz
A 45-day-old infant was referred to our clinic for unilateral hypopyon. The mother indicated noticing a whitish color change in the left eye multiple times that resolved rapidly. However, at the time of consultation, the whiteness was more intense and was retained for almost 2 weeks. The baby was examined under general anesthesia and found to have hypopyon that gave a level of about 2 mm in the left eye. No pathology was observed in the visible areas of the iris. Intraocular pressure (IOP) was 13 mmHg (Tono-Pen®, TP; Reichert, New York, USA) and the fundus examination was completely normal. Anterior and posterior segment examinations of the right eye were normal and IOP was 12 mmHg. B-scan ultrasound examinations of both eyes were within normal limits. Cranial and orbital MRI scans were reported to be normal as well. Complete blood count, along with the erythrocyte sedimentation rate and C-reactive protein levels, was within normal limits. Langerhans cell histiocytosis and granulomatous infections (tuberculosis and syphilis) were investigated. Syphilis was excluded by serological tests and interferon gamma release assay (IGRA) was applied for exclusion of tuberculosis. Examinations of the infant by the pediatrician and the blood tests along with cranial and orbital MRI revealed no pathology; therefore, Langerhans cell histiocytosis was also excluded.
Upper Limit of Retinal Nerve Fibre Layer Thickness in Patients with Pseudopapilloedema
Published in Neuro-Ophthalmology, 2022
Varsha Pramil, Mary Tam, Laurel N. Vuong, Thomas R. Hedges
Recently, various studies have attempted to determine the most useful imaging modality in differentiation of pseudopapilloedema and papilloedema. For example, B-scan ultrasonography has been suggested as one of the best methods for diagnosing patients with pseudopapilloedema and specifically, patients with pseudopapilloedema and buried drusen.13,14 The cost-effectiveness of using B-scan ultrasonography to make a diagnosis before neuroimaging or additional invasive tests in patients suspected to have papilloedema has also been documented.15 Although B-scan ultrasonography has been shown to be useful, it is not available in all clinics and requires a trained technician.13,16 Unlike B-scan ultrasonography, OCT devices are widely available and easy to use. Because it is non-invasive and can be used as an initial test like B-scan ultrasonography, we can also assume that it would be as cost-effective. Additionally, EDI-OCT has been shown to provide unparalleled optic nerve head drusen visualisation and is able to differentiate pseudopapilloedema from papilloedema with high specificity and sensitivity.16–18
Ultrasonic ocular dimensions and anthropometry in normal and myopic eyes: a case-control study
Published in Expert Review of Ophthalmology, 2022
Faosat Olayiwola Jinadu, Iskilu Adekunle Jolaoso, Modupe Balogun, Tawaqualit Abimbola Ottun, Ufuoma Oluwaseyi Olumodeji, Ayokunle Moses Olumodeji
There was consistency between ocular biometric measurements obtained by B-mode and A-mode ultrasonography in this study (Table 7). This is in support of the growing belief in the accuracy of B-scan in the assessment of ocular biometry [18,28,29]. Previous studies by Yang et al. [21], Olivier et al. [28], and Abu et al. [29] on myopic eyes with cataracts found no significant difference in ocular axial biometric measurement (AL) using A-mode, B-mode ocular scan and IOL master in individuals with AL > 26 mm. They also suggested that the accuracy and reproducibility of AL measurement using B-mode is better than contact A-mode scanning. Gonzalez et al. [18] in their study on highly myopic eyes further opined that B-scan provides a more accurate AL measurement in calculating intraocular lens power than the A-scan because of its ability to locate the macula which commonly bulges to form staphyloma (and thus an increase in ocular axial length) in highly myopic eyes. The ability is absent in A-scan and as such provides a false shorter AL measurement. These suggest that B-scan is a suitable alternative to the A-scan in the measurement of ocular axial parameters.