Volumetrie der Seitenventrikel bei Hunden: Untersuchung zu Intra- und Inter-Rater-Reliabilität anhand manueller Bildsegmentation

Zusammenfassung

Ziel

Volumetrische Verfahren bieten neue Ansätze für Diagnostik, Therapie und Einschätzung der Prognose neurologischer Erkrankungen. Ziel der Studie ist die Ermittlung der Intra- und Inter-Rater-Reliabilität volumetrischer Messungen bei manueller Bildsegmentation der Seitenventrikel von Hunden unter Berücksichtigung verschiedener MRT-Sequenzen, Körpermasse und Ventrikelgrößen.

Tiere, Material und Methoden

Die MRT-Datensätze von 9 Hunden, die 3 Gewichtsklassen und 3 Gruppen hinsichtlich der subjektiv eingeschätzten Ventrikelgröße repräsentieren, wurden retrospektiv aus der Datenbank unserer Klinik ausgewählt. Für jeden Patienten lagen 2D-Sequenzen in T2-, T1- und FLAIR-Wichtung in transversaler Schnittebene vor. Die Seitenventrikel wurden von 5 Untersuchern jeweils zehnmal segmentiert und volumetrisch vermessen. Zur Evaluation einer 3D-T1-Sequenz wurden 9 weitere Patienten ausgewählt und jeweils zehnmal durch einen Untersucher (JD) vermessen. Für die statistische Analyse wurden deskriptive Kennwerte sowie der Intraklassenkorrelationskoeffizient (ICC) für Intra- und Inter-Rater-Reliabilität ermittelt.

Ergebnisse

Intra-Rater-Reliabilität: Die niedrigsten Streuungswerte wurden in der 2D-T1-Sequenz für Hunde kleinerer Körper- und Ventrikelgröße ermittelt, für größere Hunden und/oder Ventrikel ergab die 3D-T1-Wichtung geringere Streuungswerte. Nur 2/36 der ermittelten ICC zeigten eine moderate Reliabilität (einmal in 2D-T1- und einmal 3D-T1-gewichteter Sequenz). Die übrigen ICC (34/36) wiesen eine geringe Reliabilität auf. Inter-Rater-Reliabilität: Die Sequenz mit der geringsten Streuung variierte stark in Abhängigkeit vom Untersucher. Alle ermittelten ICC (27/27) zeigten eine schlechte Reliabilität unabhängig von der Sequenz, der Ventrikelgröße oder dem Körpergewicht des Hundes.

Schlussfolgerungen

Die volumetrische Vermessung der Seitenventrikel beim Hund mittels manueller Segmentation weist sowohl bei Messungen durch einen als auch durch mehrere Untersucher große Schwächen hinsichtlich der Reliabilität auf.

Klinische Relevanz

Die manuelle Segmentation ist aufgrund der schlechten Reproduzierbarkeit und des hohen Zeitaufwandes als Routinediagnostik im klinischen Alltag nicht praktikabel.

Abstract

Objective

Volumetric methods offer new approaches for the diagnosis and treatment of neurologic diseases, as well as for an improved assessment of prognosis. The aim of this study was to determine the intra- and inter-rater reliability of volumetric measurements in manual image segmentation of the lateral ventricles of dogs, taking different sequences, body mass and lateral ventricle size into account.

Animals, Materials and Methods

MRI datasets of 9 dogs, representing 3 different body mass groups and 3 different ventricular size groups, were obtained retrospectively from the image database of our clinic. For each patient, 2D sequences were available in T2, T1 and FLAIR weighting in the transverse plane. The lateral ventricles were segmented and measured volumetrically 10 times each by 5 raters. A further 9 dogs were selected for evaluation of a 3D T1 sequence. One of the raters (JD) performed segmentation and measurement 10 times. Statistical analysis included descriptive data and calculation of intraclass correlation coefficient (ICC) for intra- and inter-rater reliability.

Results

Intra-rater reliability: The smallest variation in values was measured in the T1 sequence for dogs with small body mass and small ventricular size. For larger dogs and larger lateral ventricles, the 3D T1 sequence showed less variation. Only 2/36 calculated ICCs indicated moderate reliability (1 each for T1 and 3D T1 sequences). The remaining ICC (34/36) indicated poor reliability. Inter-rater reliability: The sequence with the least variation was observer dependent. All calculated ICCs (27/27) indicated poor reliability regardless of sequence, body mass or subjective ventricular size.

Conclusions

Volumetric measurement of canine lateral ventricles by manual segmentation shows major weaknesses in terms of reliability, both for single and multiple examiner measurements.

Clinical relevance

Manual segmentation as performed in this study is not suitable for routine clinical use due to poor reliability and time-consuming application.

Schlüsselwörter

Gehirn - MRT - ITK-SNAP - Bildverarbeitung - Sequenzen

Keywords

Brain - MRI - ITK-SNAP - image processing - sequences

Publication History

Article published online:
15 April 2025

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