Archive for January, 2012

Interpretation of OCT images-OCT pitfalls 2

Sunday, January 29th, 2012

Interpretation of OCT is awareness!
Interpretation of an OCT image means brightening of something, explaining and laying out the findings. OCT images are some kind of a transmitter, the interpreter is the receiver of an hidden information. Your answers to an OCT image are linked to your experiences, your interest and willingness to lay down the blinders and your prejudices. The answer to a question also affects the other answers.
Put nothing into the image what is not there!
It’s a challenge to record a good OCT image.  The even greater challenge is the correct interpretation! A major risk ist the danger of subjectivity and a rapid satisfaction. Search the challenge of OCT images! Nothing is more boring in your career as an eye doctor when you do the same every day.

PDFPitfalls with OCT part 2 optical coherence tomography getoct (summary, PDF)

Pitfalls with OCT getoct academy part 2

As a source of enlightenment: getoct.com database
A big help is to consider as many OCT images as possible to achieve a “cerebral calibration “. Hundreds of annotated OCT images and videos are waiting to be discovered, through you.

Don’t miss anything really occurring
Dr. Hasler says at the getoct academy 2011, that a perfect instruction of the patient leads to good OCT images. You have first to prepare a good timing to start the recording at the right moment. It is of advantage to get both: OCT scan and corresponding infrared image of the fundus. These images are linked to each other and improve the orientation. If the scans are not perfect, it is worthwhile to start again. Immediately delete useless images to keep your computer clean.

The algorithme (red line) follows the wrong way and leads to an erroneous measurement.

Dr. Hasler: the algorithme (red line) follows the wrong way and leads to an erroneous measurement.

Algorithme makes mistakes (red/white line): OCT mapping and thickness imaging is nonsense (X).

Algorithme makes mistakes (red/white line): OCT mapping and thickness imaging is nonsense (X) by Dr. Hasler.

 

Highly myopic eyes are difficult

OCT scanners are designed for normal-sighted eyes and sometimes have a button for highly myopic eyes. An oblique cut makes the algorithm work hard and leads  more frequently to errors. Thus one has to check only the individual cross-sections of whether the algorithm has done his work satisfactorily.
The quality of an individual OCT cut influences the construction and the representation of the three-dimensional volume. If the cross section is poor in quality, the 3D representation is useless.
3D images are a summary of cross-sections and if they look strange you have to switch back and look at the cross section level. The OCT scanner analyzes the samples using an algorithm, so a „ simple calculation method“. The 3D OCT has the advantage that you can quickly scroll through a lesion, to detect and to estimate the dimensions and to identify mistakes easier.
In addition, 3D OCT is a good training to discover the anatomy of the eye and the problem is explained in an impressive way to the patient.
Interpretation of OCT
The most difficult task is the correct interpretation of the OCT images. There is an enormous achievement to get a good OCT image. Good interpretation is a real challenge.

Dr. med. Peter Maloca recommends a multi-stage procedure for an accurate diagnosis:
Checklist OCT pre-interpretation:

1. OCT practice:
Only practice makes perfect! Who does not look exactly on OCT images, will never learn it.
2. OCT network – calibration
Get in touch with experienced OCT users. Visit an OCT congress, for example the annual getoct academy in Lucerne (in German) and join the community at getoct.com. Upload your pictures to getoct.com, ask the community.
 
OCT interpretation in 5 getoct steps by Dr. med. Peter Maloca:
1. Orientation: where are you?
For a proper assessment of OCT images you have to orient yourself first. Say nothing of what you can not prove or show on the OCT images!
2. Findings: describe only what you really see in simple words.
3. Summarize the findings
4. Link the findings to a diagnosis (interpretation)
5. Be honest: self-criticism/what else?
Be honest! Say nothing what you have not checked for alternatives! Don’t skip lesions! Twist nothing! There are no stupid questions. Only someone who has no questions is stupid. Serve the OCT scans and do not abuse it for your self-expression!
6. Explain: explain to the patient the diagnostic findings. If he understood it, you have understood it.
Steps of interpretation OCT by Dr Maloca

Steps of interpretation OCT by Dr Maloca

***
OCT-Interpretation von Dr. med. Peter Maloca:
1. Orientierung auf dem OCT- Bild: wo bist Du?
Für eine angemessene Bewertung der OCT-Bilder müssen Sie sich zuerst orientieren. Sagen Sie nichts, was Sie nicht beweisen können, zeigen Sie es auf den OCT-Bildern!
2. Befunde: beschreiben Sie in einfachen Worten nur, was Sie wirklich sehen.
3. Zusammenfassung der Befunde
4. Verknüpfen Sie die Befunde zu einer Diagnose (Interpretation)
5. Seien Sie ehrlich, Selbstkritik, was könnte es sonst noch sein?
Seien Sie ehrlich! Sagen Sie nichts, was sie nicht nach Alternativen geprüft haben! Lassen Sie keine Läsionen aus! Verdrehen Sie nichts! Es gibt keine dummen Fragen. Nur jemand, der keine Fragen hat, ist dumm. Missbrauchen Sie die OCT scans nicht zu Ihrer Selbstdarstellung!
6. Erkläre!
Erklären Sie dem Patienten die Befunde. Wenn er es verstanden hat, haben Sie es auch verstanden.

Copyright © 2012 getoct™ Ltd. All rights reserved.

Interpretation of OCT images-OCT pitfalls 1

Monday, January 23rd, 2012

Main problem in OCT (optical coherence tomography) is that things are interpreted in the pictures, they really do not exist.  Pitfalls with OCT, technical aspect, case presentation,  view video from getoct academy 2011.

View new video: Interpretation of OCt images- pitfalls 1_new

Interpretation of OCT images-OCT pitfalls 1 (Video)

Pitfalls with OCT part 1 optical coherence tomography getoct (summary, PDF)

It’s a great honor to welcome Dr. med. Pascal Hasler, Basel, at the 6th getoct academy in Lucerne/Switzerland. The problem with OCT congresses is, that everything  looks wonderful. Everyone seems to know everything and no one dares to admit mistakes. Therefore, Dr. Pascal Hasler will show you in this video pitfalls using OCT. In the first part technical aspects are discussed. In the second part pitfalls of interpretation are shown. Therefore it is important that there are such courses as the practice-oriented getoct academy in Lucerne!

getoct academy 2011  Dr.  Hasler Dr. Maloca

getoct academy 2011 Dr. Maloca and Dr. Hasler

Dr Hasler says that there are four main sources of error using OCT: patient dependent, cooperation between patient and examiner, wrong scanner settings and above all interpretation of OCT images, which is an extraordinary challenge.

Here is a summary of Dr. Hasler speech, held at the 6. getoct academy 3 December 2011:

Pitfalls with OCT, technical aspect, case presentation

1. Sources of error in patient
miosis: OCT in miosis is possible, but difficult due to lower signal strength, no accurate centering of laser beam
small interpalpebral space/ptosis
in dry eye use of moisturizing eyedrops before scanning
wrong indications for OCT:  with vitreous hemorrhage OCT is practically impossible
2. Cooperation between patient and examiner:
poor visual acuity is equally to poor  fixation:  expand inner fixation target, use external fixation light
restless patients: shorten scanning, ask for assistance to fix the head
alternatively use the quick scan mode even when you loose image quality
scan rather an individual, low qualitiy cross scan than a fullrange measurement
 3. Wrong settings on OCT scanner:
choose corresponding diopters, may be set automatically
the centering should be focused on the hot spot orthogonally if possible
measurement on correct eye and correctly stored
choose the right scan protocol: in children, one must often use protocols others than in adults
observe the quality of the scan signal observing the intensity chart
OCT is also useful for advanced cataract to evaluate the retina because the wavelength of the laser light is not so impeded by the cloudiness oft he cataract.

4. Interpretation of OCT
The most difficult task is the correct interpretation of the OCT images. There is an enormous challenge to get a good OCT image. Still, good interpretation of OCT iamges is an extraordinary challenge!
New video:

Interpretation of OCT images-pitfalls 1

Checklist OCT by Dr. Peter Maloca:

Dr. med. Peter Maloca recommends a multi-stage procedure for an accurate diagnosis:
1. First patient data
Is it the right patient (name, age)? Is it the right eye?
2. Anatomy
Where are normal, healthy structures?
Where are different structures?
Signs of activity (thickening, accumulation)?
3. Descriptive diagnosis
Try to describe the nature of the different structures first without trying to make a diagnosis: “I see a fine line that runs to the center of the retina, where spaces are present and there is a gap in the center of the retina”
 4. Working diagnosis – differential diagnosis
Count for possible diagnoses. Which is less? What is rare is rare. Ask your colleagues. Upload some images to getoct.com and ask your getoct friends.
 5. Diagnosis, synopsis
Which diagnosis is best suited to clinical picture and the other results?
 6. Follow-up
What happens during the next time?
The biggest mistake in OCT is to ask: does the OCT suits my diagnosis instead of matches my diagnosis to the OCT?

***

Dr. med. Peter Maloca empfiehlt ein mehrstufiges Verfahren zur korrekten OCT-Diagnose:

OCT-Checkliste von Dr. med. Peter Maloca:

1. Patientendaten
Ist es der richtige Patient (Name, Alter)? Ist es das richtige Auge?
2. Anatomie
Wo sind normale, gesunde Strukturen?
Wo sind abweichende Strukturen?
Aktivitätszeichen (Verdickungen, Einlagerungen)?
3. Deskriptive Diagnose
Beschreibe die Art der abweichenden Strukturen zuerst ohne eine Diagnose erzielen zu wollen: “Ich sehe eine feine Linie, die zur Netzhautmitte zieht, wo rundliche Räume vorhanden sind und die Netzhaut eine Lücke aufweist”
 4. Arbeits Diagnose- Differential-Diagnose
Zähle mögliche Diagnosen auf, die Dir einfallen. Welche weniger? Was selten ist, ist selten. Frage Deine Kollegen. Lade Bilder auf getoct.com hoch und frage Deine getoct friends.
5. Diagnose, Synopsis
Welche Diagnose passt am besten zum klinischen Bild und den anderen Resultaten?
6. Verlauf
Was passiert während der nächsten Zeit?

Der grösste OCT-Fehler ist die Frage, ob das OCT zur Diagnose passt anstelle von “passt die Diagnose zum OCT?”

Copyright © 2012 getoct™ Ltd. All rights reserved.