Friday, 19 January 2018

Role of CT in orbital imaging

Role of CT in orbital imaging
by
Goh Poh Sun

Computed Tomography (CT) scans are widely available, relatively cheaper than MRI (around half the price), and is the optimal method for imaging for, and excluding bony abnormalities (e.g. fractures, bony involvment in tumours), radioopaque foreign bodies, for calcification and in patients who have difficulty keeping still (scan is completed relatively quickly, in seconds, compared with 20 minutes up to an hour for comprehensive MRI imaging of the orbits, brain and MR angiography), are claustrophobic, and who are medically unstable and require a rapid scan (e.g. head trauma, facial trauma, to exclude intracranial haemorrhage, orbital and globe trauma, including penetrating injuries), and to quickly evaluate for aneurysms and CC fistulas.

Multiplanar imaging in not only coronal and sagittal to add to axial planes, but also curved planes, and 3D recontructions, as well as CT angiography, with an without 3D visualisation of the main neck and intracranial vessels (including quick bone subtraction) can all be quickly and rapidly obtained with modern CT scanners.

Examples of CT scans in facial trauma, with 3D reconstructions, globe trauma, FB imaging, orbital infection (subperiosteal abscess with sinusitis), and sinus tumours involving orbit, and skull base can be seen below). PET CT isotope imaging can also be obtained to assess for disease activity (e.g. in lymphoma), or to evaluate for active disease vs scar in tumour workup and follow up (see below). These examples also show the clinically useful detail for conditions above, as well as localising air (in trauma, and infection), as well as location and contours of implants (globe, and in orbital trauma surgery and reconstructions).

Intravenous (iodine) containing contrast can be used to evaluate for tumour enhancement, vascularity, to evaluate for feeding and draining vessels in AVMs and large fistulas; and to evaluate for progressive enhancement in orbital venolymphatic malformations.

https://en.wikipedia.org/wiki/CT_scan

https://www.nibib.nih.gov/science-education/science-topics/computed-tomography-ct

https://www.healthcare.siemens.com/computed-tomography

https://www.gehealthcare.com/en/products/computed-tomography

https://www.usa.philips.com/healthcare/solutions/computed-tomography/ct-scanners


Technique
-New scanners, isotropic 3D/multislice imaging with one acquisition
-Spatial resolution
-Use of contrast
-3D reconstructions, Stereotactic surgical planning
-PET-CT


Anatomy



Application

-Bony detail - fractures, tumour involvement, integrity, invasion

-Calcification

-FB

-Infection, Collection, Fluid, Gas

-Implants, reconstruction

-Tumour (active)


Examples




































































































































https://learningheadandneckradiology.blogspot.sg/2012/05/case-challenge-orbit-set-1.html




Case 1


Case 2


Case 3


Case 4


Case 5


Case 6


Book chapters in

above screenshot from

published 28 April 2019


Goh P.S. (2019) Imaging: Computerised Tomography. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Sundar G., Young S.M., Goh P.S., Wu B., Nga M.E., Amrith S. (2019) Fibro-osseous Lesions: Fibrous Dysplasia. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Orbital Cellulitis: Bacterial. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Thyroid Eye Disease. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Sundar G., Young S.M., Goh P.S., Wu B., Nga M.E., Amrith S. (2019) Sarcoidosis. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Xanthogranuloma. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Kimura Disease. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Young S.M., Amrith S., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Non-specific Orbital Inflammatory Disease. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Sundar G. (2019) Distensible Venous Malformation. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Lacrimal Gland: Pleomorphic Adenoma. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) MALT Lymphoma. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Follicular Lymphoma. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Sundar G., Young S.M., Goh P.S., Wu B., Nga M.E., Amrith S. (2019) T-Cell Lymphoma. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Sebaceous Gland Carcinoma. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Mucinous Carcinoma. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore

Amrith S., Young S.M., Goh P.S., Wu B., Nga M.E., Sundar G. (2019) Paranasal Sinus Mucocoele. In: Amrith S., Sundar G., Young S. (eds) Ocular Adnexal Lesions. Springer, Singapore


https://learningheadandneckradiology.blogspot.sg/2016/06/imaging-in-thyroid-eye-disease-role-of.html




https://padlet.com/dnrgohps/ImagingInThyroidEyeDisease

Educational exhibit for ASNR 2017
Betsy Soon and Goh Poh Sun
ASNR 2017 Annual Scientific Meeting, April 22 to 27, 2016, Long Beach Convention Center, Long Beach, California


References

Purohit BS, Vargas MI, Ailianou A, Merlini L, Poletti PA, Platon A, Delattre
BM, Rager O, Burkhardt K, Becker M. Orbital tumours and tumour-like lesions:
exploring the armamentarium of multiparametric imaging. Insights Imaging. 2016
Feb;7(1):43-68. doi: 10.1007/s13244-015-0443-8. PubMed PMID: 26518678; PubMed
Central PMCID: PMC4729705.
https://www.ncbi.nlm.nih.gov/pubmed/26518678

Postoperative Imaging of the Orbital Contents Michael J. Reiter, Ryan B. Schwope, Jonathan A. Kini, Gerald E. York, and Abraham W. Suhr RadioGraphics 2015 35:1, 221-234

Tawfik, H. A., Abdelhalim, A., & Elkafrawy, M. H. (2012). Computed tomography of the orbit – A review and an update. Saudi Journal of Ophthalmology, 26(4), 409–418. http://doi.org/10.1016/j.sjopt.2012.07.004

Hande, P. C., & Talwar, I. (2012). Multimodality imaging of the orbit. The Indian Journal of Radiology & Imaging, 22(3), 227–239. http://doi.org/10.4103/0971-3026.107184

Goh PS, Gi MT, Charlton A, Tan C, Gangadhara Sundar JK, Amrith S. Review of
orbital imaging. Eur J Radiol. 2008 Jun;66(3):387-95. doi:
10.1016/j.ejrad.2008.03.031. Review. PubMed PMID: 18501542.
https://www.ncbi.nlm.nih.gov/pubmed/18501542


see also

"Technology enhanced learning or eLearning allows educators to expand access to educational content, promotes engagement with students and makes it easier for students to access educational material at a time, place and pace which suits them. The challenge for educators beginning their eLearning journey is to decide where to start, which includes the choice of an eLearning tool and platform. This article will share one educator's decision making process, and experience using blogs as a flexible and versatile integrated eLearning tool and platform. Apart from being a cost effective/free tool and platform, blogs offer the possibility of creating a hyperlinked indexed content repository, for both created and curated educational material; as well as a distribution and engagement tool and platform. Incorporating pedagogically sound activities and educational practices into a blog promote a structured templated teaching process, which can be reproduced. Moving from undergraduate to postgraduate training, educational blogs supported by a comprehensive online case-based repository offer the possibility of training beyond competency towards proficiency and expert level performance through a process of deliberate practice. By documenting educational content and the student engagement and learning process, as well as feedback and personal reflection of educational sessions, blogs can also form the basis for a teaching portfolio, and provide evidence and data of scholarly teaching and educational scholarship. Looking into the future, having a collection of readily accessible indexed hyperlinked teaching material offers the potential to do on the spot teaching with illustrative material called up onto smart surfaces, and displayed on holographic interfaces."

Above abstract from 
Goh PS. Using a blog as an integrated eLearning tool and platform. Med Teach. 2016 Jun;38(6):628-9.
[2015 Nov 11:1-2. Epub ahead of print]


"By reviewing research on medical performance and education, the author describes evidence for these representations and their development within the expert- performance framework. He uses the research to generate suggestions for improved training of medical students and professionals. Two strategies— designing learning environments with libraries of cases and creating opportunities for individualized teacher-guided training—should enable motivated individuals to acquire a full set of refined mental representations. Providing the right resources to support the expert- performance approach will allow such individuals to become self-regulated learners—that is, members of the medical community who have the tools to improve their own and their team members’ performances throughout their entire professional careers.'
from abstract of
Ericsson KA. Acquisition and maintenance of medical expertise: a perspective from the expert-performance approach with deliberate practice. Acad Med. 2015 Nov;90(11):1471-86. doi:10.1097/ACM.0000000000000939. PubMed PMID: 26375267.

example blogpost link below

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