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.
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. 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!
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:
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?”