Incidences of Terminal Zones of Myelination: An Evaluation of Patients aged 3–30 Years

Öz

Abstract Aim: Studies on terminal zones of myelination (TZM) generally focus on the infant to early childhood periods. Information concerning the incidence and localization in adulthood is rare and controversial. To determine the localization and frequency TZM in patients aged 3–30 years using magnetic resonance imaging (MRI). Material and Method: Images of 560 patients aged 3-30 years, whose cranial MRIs were reported as normal, were re-evaluated by two radiologists using a double-blind, retrospective method. Five different white matter (WM) regions (parietal peritrigonal WM; frontal, temporal, parietal, and insular subcortical WM) were reviewed for TZM. Turbo spin echo T2- and T1-weighted imaging and T2 fluid-attenuated inversion recovery sequences were used. Results: The incidences of TZM in all age groups were 28.7% in the insula, 14.6% in the temporal lobes, and 5.2% in the peritrigonal region. TZM were localized most commonly in the insula, followed by the temporal poles. The presence of peritrigonal TZM after 5 years of age was very rare (2.6%). Interobserver agreement was significant for all regions (Kappa value < 0.05). Conclusion: We detected TZM most often in the insular subcortical WM. It should be noted that insular and temporal TZM can be observed quite frequently (13.8% and 9.8%, respectively), even in third decade.

Anahtar Kelimeler

• insula
• subcortical white matter
• myelination
• MRI

Terminal Myelinasyon Zonlarının Görülme Sıklığı: 3-30 Yaş Arası Değerlendirme

Öz

Öz Amaç: Terminal miyelinasyon zonları (TMZ) ile ilgili çalışmalar genellikle infant-erken çocukluk dönemlerini kapsayacak şekilde yapılmıştır. Erişkinlikte insidans ve lokalizasyonu ile ilgili bilgiler nadirdir ve tartışmalıdır. Amacımız, manyetik rezonans görüntüleme (MRG) ile 3-30 yaş arası hastalarda TMZ lokalizasyonunu ve sıklığını belirlemektir. Gereç ve Yöntem: Kranial MRG’leri normal olarak raporlanan, yaşları 3-30 arasında değişen 560 hastanın görüntüleri, iki radyolog tarafından çift kör, retrospektif yöntemle tekrar değerlendirildi. TMZ için beş farklı beyaz cevher (BC) bölgesi (parietal peritrigonal BC; frontal, temporal, parietal ve insular subkortikal BC) tekrar gözden geçirildi. T2 ve T1 ağırlıklı turbo spin eko ve T2-FLAIR (fluid-attenuated inversion recovery) sekansları kullanıldı. Bulgular: Tüm yaş gruplarında TMZ insidansı insulada %28.7, temporal loblarda %14.6 ve peritrigonal bölgede %5.2 idi. TMZ, en sık insulada lokalizeydi, bunu temporal poller izliyordu. Beş yaşından sonra peritrigonal TMZ varlığı çok nadirdi (%2.6). Gözlemciler arası uyum tüm bölgeler için anlamlıydı (Kappa değeri < 0.05). Sonuç: TMZ’yi, en sık insular subkortikal BC'de saptadık. Insular ve temporal TMZ’lerin, üçüncü dekatta bile oldukça sıklıkla (sırasıyla %13.8 ve %9.8) izlenebileceği unutulmamalıdır.

Anahtar Kelimeler

• insula
• subcortical white matter
• myelination
• MRI

Kaynakça

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