Three dimensional MRI study: Safety of short versus long needle peribulbar anesthesia

Three-Dimensional Constructive Interference in Steady State (3D CISS) Imaging and Clinical Applications in Brain Pathology

Three-dimensional constructive interference in steady state (3D CISS) is a steady-state gradient-echo sequence in magnetic resonance imaging (MRI) that has been used in an increasing number of applications in the study of brain disease in recent years. Owing to the very high spatial resolution, the strong hyperintensity of the cerebrospinal fluid signal and the high contrast-to-noise ratio, 3D CISS can be employed in a wide range of scenarios, ranging from the traditional study of cranial nerves, the ventricular system, the subarachnoid cisterns and related pathology to more recently discussed applications, such as the fundamental role it can assume in the setting of acute ischemic stroke, vascular malformations, infections and several brain tumors. In this review, after briefly summarizing its fundamental physical principles, we examine in detail the various applications of 3D CISS in brain imaging, providing numerous representative cases, so as to help radiologists improve its use in imaging protocols in daily clinical practice.

Computed tomography scan measurements of the globe and orbit to assess the risks of traumatic complications from medial peribulbar anaesthesia

Complications of peribulbar anaesthesia include retrobulbar haemorrhage, globe perforation and brainstem anaesthesia. Therefore, this study took measurements relating the proximity of medial canthus to the optic nerve and also the safe angle between orbit and globe using 200 multiplanar reconstructed computed tomography (CT) images of the orbit. The principal results show that in 1.5% of the sample, the optic nerve is within 20 mm of the medial canthus, with a minimum distance of 15 mm. One% have a safe angle of 10 degrees or less between bone and globe. None of the demographic data, nor axial length were predictive of these results. We have shown that there are a minority of patients with unusual orbital anatomy. This places them at a theoretical higher risk of complications. These cases are not currently predicted by measured data.

A cadaveric feasibility study of the intraorbital cannula injections of hyaluronidase for initial salvation of the ophthalmic artery occlusion

BACKGROUND

Phthisis bulbi may follow cosmetic filler injections. Early attempts to inject hyaluronidase into the orbit after detection of devastating signs and symptoms may potentially mitigate the complications.

METHODS

Cannula routes along the orbital walls were studied. Depths of injections were determined in 30 dry skulls. Deep cannula insertions were carefully performed while avoiding exiting the orbit. Forty-six cadaveric orbits with intravascular latex injection were dissected to determine injection techniques, to verify structures at risk along the routes, and to evaluate substance dispersion.

RESULTS

The limited depths of the superior, lateral, medial, and inferior injection routes were 4.2, 3.8, 3.6, and 2.5 cm respectively, while the orbital width was 3.9 cm. The superior parasagittal injection was effective and rarely tears the superior ophthalmic vein, artery, and the optic nerve. The medial injection should be avoided because it may injure the lacrimal sac, the ophthalmic artery, and the optic nerve. Without limited depth, the lateral injection may damage the lacrimal gland and artery and proceeds to damage the optic nerve. The inferior parasagittal injection tends to exit into the infratemporal fossa but the inferior oblique injection may be safer and effective but more complicate with the depth of 4.2 cm.

CONCLUSION

The superior parasagittal injection is a recommended simple technique with a minimal chance of vascular injury. The inferior oblique injection requires more skill but it may be safer because of the lower position. For safety reasons, depth of each cannula insertion should not exceed the orbital width.

NO LEVEL ASSIGNED

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