Heschl?in Transvers Giruslarının Anatomisi ve Morfolojik Varyasyonları

Abstract

Amaç: Heschl’in transvers girusları temporal lobun üst yüzününün arka kısmında yer alır. Primer işitme merkezi burada bulunur. Heschl’in transvers giruslarının morfolojisi işitme ile ilgili semptomları olan hastaların değerlendirilmesi sırasında önemli olabilmektedir. Çalışmamızın amacı Heschl’in transvers giruslarının morfolojik varyasyonlarını tanımlamak ve bu varyasyonların klinik önemini vurgulamaktır. Gereç ve Yöntemler: Çalışmaya, Radyoloji Anabilim Dalı MRG ünitesinde değerlendirilen ve başvuru yakınması başağrısı olan 18 hasta ve 22 sağlıklı gönüllü olmak üzere toplam 40 olgu dahil edilmiştir. Patolojisi bulunmayan ve çalışmaya alınan olgulara transvers düzlemde 3 boyutlu ince kesitli T1 ağırlıklı gradient eko görüntüler alındı. Girus, sagittal ve koronal reformat görüntülere göre omega ya da kalp şekilli olarak sınıflandı. Ayrıca girus sayı ve şekilleri hemisferik dominansa göre de analiz edildi. Bulgular: Kırk olgudaki 80 hemisferin 67’sinde %84 tek, 13’ünde %16 ise 2 adet Heschl girusu saptandı. Üç veya daha fazla Heschl girusu olan hemisfer yoktu. 93 Heschl girusunun 79’u omega, 14’ü ise kalp şeklinde idi. Hemisferik dominans açısından değerlendirildiğinde otuzaltı dominant hemisferde dört, otuzbir nondominant hemisferde 9 tanesinde iki Heschl girusu saptandı.Sonuç: Çalışmamızda Heschl giruslarının normal populasyondaki varyasyon gösterilmiştir. Fonksiyonel MRG gibi araştırmalarda bu girusların tanımlanması ve gözden kaçırılmaması önemlidir

Keywords

• Beyin, Anatomi, Heschl girusları, MR görüntüleme

Heschl’s Transverse Gyri: Anatomy and Morphological Variations

Abstract

Objective: Heschl’s gyrus is the primary auditory cortex in humans. It is located in the posterior part of the area on the superior surface of the temporal lobe, or the planum temporale. The number and shape of this gyrus may differ. In this study, we aimed to investigate the number and shape variations of the Heschl gyrus in normal subjects by using MRI.Material and Methods: Eighty hemispheres in 40 subjects were evaluated. Of these subjects, 18 were patients with headache, evaluated in our MR imaging unit, and 22 were healthy volunteers. After the routine sequences, three dimensional transverse T1-weighted fast field echo images were obtained. The shape of the gyrus was classified as omega or heart shaped according to the images. The number of gyri in each hemisphere was noted. Number and shapes were analyzed according to right/left and dominant/non-dominant. Results: Of the 80 hemispheres, a single gyrus was present in 67 %84 and two gyri were present in 13 %16 . Three or more Heschl gyri were not seen. Of the total 93 Heschl gyri, 79 %85 were omega shaped and 14 %15 were heart shaped. With regard to dominance; thirty-six of the dominant hemispheres had one and 4 had two Heschl gyri. Thirty-one of the non-dominant hemispheres had one and 9 had two gyri. Conclusion: Our study shows that, among normal subjects, the number and shape of Heschl’s gyrus may show variations. In clinical investigations where the identification of this gyrus is needed, such as functional MRI studies, these variations should not be overlooked

Keywords

• Brain, Anatomy, Heschl’s gyrus, MR imaging

References

1. Hackett TA. Anatomic organization of the auditory cortex. Handbook of Clinical Neurology 2015; 129:27- 53.
2. Atagun MI, Sikoglu EM, Can SS, Karakas-Ugurlu G, Ulusoy-Kaymak S, Caykoylu A, Algin O, Phillips ML, Moore CM, Ongur D. Investigation of Heschl’s gyrus and planum temporale in patients with schizophrenia and bipolar disorder: A proton magnetic resonance spectroscopy study. Schizophr Res 2015; 161:202-9.
3. Yousry TA, Fesl G, Buttner A, Noachtar S, Schmid UD. Heschl’s gyrus - Anatomic description and methods of identification on magnetic resonance imaging. Int J Neuroradiol 1997; 3:2-12.
4. Ulualp SO, Biswal BB, Yetkin FZ, Kidder TM. Func- tional magnetic resonance imaging of auditory cortex in children. Laryngoscope 1998;108:1782-6.
5. Bamiou DE, Musiek FE, Luxon LM. Aetiology and clinical presentations of auditory processing disorders - a review. Arch Dis Child 2001; 85:361-5.
6. Bernal B, Altman NR. Auditory functional MR imaging. Am J Roentgenol 2001; 176:1009-15.
7. Hirayasu Y, McCarley RW, Salisbury DF, Tanaka S, Kwon JS, Frumin M, Snyderman D, Yurgelun-Todd D, Kikinis R, Jolesz FA, Shenton ME. Planum temporale and Heschl gyrus volume reduction in schizophrenia- A magnetic resonance imaging study of first-episode patients. Arch Gen Psychiat 2000; 57:692-9.
8. Kwon JS, McCarley RW, Hirayasu Y, Anderson JE, Fischer IA, Kikinis R, Jolesz FA, Shenton ME. Left planum temporale volume reduction in schizophrenia. Arch Gen Psychiat 1999; 56:142-8.

9. Gaser C, Nenadic I, Volz HP, Buchel C, Sauer H. Neuroanatomy of ‘hearing voices’: A frontotemporal brain structural abnormality associated with auditory hallucinations in schizophrenia. Cerebral Cortex 2004; 14:91-6.
10. Dickey CC, McCarley RW, Voglmaier MM, Frumin M, Niznikiewicz MA, Hirayasu Y, Fraone S, Seidman LJ, Shenton ME. Smaller left Heschl’s gyrus volume in patients with schizotypal personality disorder. Am J Psychiat 2002; 159:1521-7.
11. Marie D, Jobard G, Crivello F, Perchey G, Petit L, Mellet E, Joliot M, Zago L, Mazoyer B, Tzourio-Mazoyer N. Descriptive anatomy of Heschl’s gyri in 430 healthy volunteers, including 198 left-handers. Brain structure & function. 2015; 220:729-43.