Publication: Tiroid Oftalmopati'de Orbital Dokuların Manyetik Rezonans Görüntülerinin 3 Boyutlu Hacim Oluşturma Tekniği ile Değerlendirilmesi
Abstract
Amaç: Tiroid oftalmopatide, orbital dokulardaki alan ve hacim değişikliklerinin manyetik rezonans görüntüleme (MRG) ile tespit edilmesi ve klinik aktivite ile ilişkisinin değerlendirilmesi amaçlanmaktadır. Gereç ve Yöntem: Ondokuz Mayıs Üniversitesi Tıp Fakültesi Hastanesi, Göz Hastalıkları kliniğinde Ocak 2015 – Aralık 2019 tarihleri arasında tiroid oftalmopati (TİO) tanısı ile takip edilmiş 30 hasta ile orbital patolojisi olmayan 30 birey (kontrol grubu olarak) çalışmaya alındı. Hasta verileri retrospektif olarak incelendi ve kaydedildi. Manyetik rezonans (MRG) görüntülerinden volume rendering tekniği kullanılarak, ekstra oküler kaslar (EOK), retroorbital yağ doku (ROY), retroorbital bölge (ROB), kemik orbita (KO), retrobulber optik sinir (RBOS), optik kanal içi optik sinir (OS) ve glob dahil orbital dokuların alanları ve hacimleri oluşturuldu. Alan ve hacim ölçümü için osirix MD programı kullanıldı. MR görüntüleri digital imaging and communications in medicine (DICOM) formatında osirix MD bilgisayar programına aktarıldıktan sonra hacmi ve alanı ölçmek için orbital doku sınırları manuel olarak işaretlendi. Programdan işaretlenen bölgenin alan ve hacim bilgisi otomatik olarak alındı. Rektus kas hacimleri matematiksel olarak toplanarak total kas hacmi (TKH) hesaplandı. Orbital doku alan ve hacimleri birbirine oranlandı. Ekzoftalmus miktarı ölçülerek radyolojik Hertel (R-Hertel) olarak kaydedildi. Bu ölçümler kontrol grubundaki MRG görüntülerinden oluşturulan orbital doku alan, hacim ve oranları ile karşılaştırıldı. Hasta grubunda, iki göz arasında da karşılaştırma yapıldı. Ayrıca hesaplanan orbital ölçümlerin klinik aktivite skoru (KAS), diplopi varlığı, hertel exoftalmometre ölçümleri ve tiroid fonksiyon testleri ile korelasyonu analiz edildi. Bulgular: Çalışma grubunda 15'i kadın, 15'i erkek ve yaş ortalaması 45,6±11,1 (20-66) yıl olan 30 hastanın 60 gözü incelendi. Kontrol grubunda 18'i kadın, 12'si erkekti ve yaş ortalaması 50,3±9,6 (27-63) yıl olan 30 hastanın 60 gözü incelendi. Hasta grubu ile kontrol grubu arasında glob hacmi ve alanı benzerdi (p >0,05). Retrobulber OS alan ve hacmi hastalarda daha düşüktü (p ˂0,05). Diğer tüm orbital doku alan, hacim ve oranları hasta grubunda kontrol grubuna göre yüksek bulundu (p ˂0,05). Hasta grubunda klinik ölçümler, bulgular ve MR ölçümlerinde iki göz arasında anlamlı fark yoktu ve simetrik tutulum vardı. Klinik aktivite skoru negatif olan hastaların EOK, ROY, ROB ve KO alan ve hacimleri kontrol grubundan yüksekti (p ˂0,05). Klinik aktivite skoru ile en çok korele olan parametreler TKH (r =0,825 p ˂0,001), R-Hertel (r =0,783 p ˂0,001) ve EOK'den inferior rektus (İR) hacim ve alanı (sırası ile r =0,797 ve r =0,755 p ˂0,001) idi. Retroorbital YD hacmi KAS ile ilişkiliydi fakat korelasyon kaslara göre daha düşüktü (r =0,495 p ˂0,001), ROB ve KO hacmi ve alanı da KAS ile güçlü korelasyon gösteriyordu (p ˂0,001). Diplopisi olanlarda, YD ölçümleri dışındaki tüm orbital ölçümler olmayanlardan yüksekti. Klinik olarak ölçülen Hertel ile R-Hertel (r =0,825 p ˂0,001) çok güçlü, TKH, tüm EOK hacimleri, ROB hacmi ve alanı güçlü, ROY hacmi ve alanı orta düzeyde koreleydi. Herteli en fazla etkileyen parametreler, hacimlerde 1 cm3 artışı ile 2,32 mm Hertel artışı yapan TKH ve oranlarda 0,1 birim artışı ile 3,72 mm Hertel artışı yapan TKH/KOH oranıydı. Klinik aktivite değerlendirilmesinde en kullanışlı parametreler, medial rektus (MR) hacmi (%81 sensitif, %95 spesifik, cut-off: 0.90 cm3), TKH (%81 sensitif, %88 spesifik, cut-off: 3,42 cm3), R-Hertel (%90 sensitif, %72 spesifik, cut-off: 23,2 mm) ve MR hacmi/KOH oranı (%81 sensitif, %95 spesifik, cut-off: 0,069) olarak bulundu. Klinik aktivite skoru pozitif hastalarda antiTG seviyesi daha yüksekti (p =0,043). Retroorbital yağ doku ve ROB hacimleri ile sT3 ve antiTG arasında orta düzeyde korelasyon vardı. Optik sinir hacmi, aksiyel ve koronal alanı ile proksimal alanı hasta grubunda daha düşüktü (p <0,05). Klinik aktivite artışı ile OS hacmi artmakta (r =0,375 p =0,003) ve aksiyel alanı azalmaktaydı (r =-0,324 p =0,012). Retrobulber OS proksimal alanı ile TKH (r =-0,336 p =0,009) ve ROY hacmi (r =-0,732 p ˂0,001), distal alanı ile ROY hacmi (r =-0,663 p ˂0,001) negatif korelasyon gösteriyordu. Radyolojik Hertel ile retrobulber OS hacmi arasında pozitif (r =0,275, p =0,034), OS aksiyel alanı arasında negatif bir korelasyon vardı (r =-0,338, p =0,008). Optik kanal içi OS alanı hasta grubunda daha fazlaydı (p =0,005). Optik kanal içi OS alanı ile retrobulber OS aksiyel (r =-0,314, p =0,015) ve proksimal (r =-0,343 p =0,007) alanları arasında negatif bir korelasyon vardı. Sonuç: Tiroid oftalmopatili hastalarda MRG görüntüleri kullanılarak volume rendering tekniği ile orbital dokuların alan ve hacim ölçümleri yapılabilir. Hastalığın inaktif evresinde bile tüm orbital doku alan ve hacimleri artmaktadır. Kas hacmi daha belirgin olmak üzere tüm VI orbital yumuşak doku (kas, yağ, total) ve KO hacimlerinin artışı KAS ile koreledir. Hertel ölçümüne en çok etki eden parametreler TKH ve onun KOH'ye oranıdır. Klinik aktivite değerlendirmesinde MR hacmi, TKH, R-Hertel ve MR/KOH oranı kullanılabilir. Artan yumuşak doku hacmi OS'e proksimal yarıda daha fazla olmak üzere basıya neden olmaktadır. Anahtar kelimeler: Graves Oftalmopati, Hacim Oluşturma Tekniği, Manyetik Rezonans Görüntüleme, Orbita, Orbital MRI, Tiroid İlişkili Oftalmopati.
Objectives: To detect area and volume changes in orbital tissues in thyroid ophthalmopathy by magnetic resonance imaging (MRI) and to evaluate its relationship with clinical activity. Materials and Methods: Thirty patients who had been followed-up with the diagnosis of thyroid associated ophthalmopathy (TAO) between January 2015 and December 2019 in Ondokuz Mayıs University Medical Faculty Hospital, Ophthalmology Clinic and 30 individuals without orbital pathology (as a control group) were included in the study. Patient's data were analyzed retrospectively and recorded. The areas and volumes of extraocular muscles (EOM), retroorbital fat tissue (ROF), retro-orbital region (ROR), bony orbit (BO), retrobulbar optic nerve (RBON), optic nerve (ON) inside the optic canal, and globe were created using the volume rendering technique from magnetic resonance (MRI) images. The volume and area of orbital tissues was calculated using the osirix MD analysis software tool. After the MR images were recorded as digital imaging and communications in medicine (DICOM) in the osirix MD software program, the borders of orbital tissues were manually marked to measure the volume and area. The area and volume of that region were automatically taken. Total muscle volume (TMV) was calculated by summing rectus muscle volumes mathematically. The ratios of orbital tissue areas and volumes were calculated. The amount of exophthalmos was measured and recorded as radiological Hertel (R-Hertel). These measurements were compared with orbital tissue areas, volumes, and ratios created from MRI images of the control group. A comparison between the two eyes was also performed in the study group. In addition, the correlation of orbital measurements with clinical activity score (CAS), presence of diplopia, hertel exophthalmometer measurements, and thyroid function tests were analyzed. Results: Sixty eyes of 30 patients with the mean age of 45.6±11.1 (20-66) years, 15 women and 15 men, were examined in the study group. Sixty eyes of 30 patients with the mean age of 50.3±9.6 (27-63) years, 18 women and 12 men, were examined in the control group. The area and volume of globe were similar between the study and the control groups (p> 0.05). The VIII area and volume of RBON were lower in the study group (p <0,05). The areas, volumes, and ratios of the other orbital tissues were higher in the study group than the control group (p ˂0.05). In the study group, there was no significant difference between the two eyes in clinical measurements, findings and MR measurements, and the involvement was symmetrical. The areas and volumes of EOMs, ROFT, ROR, and BO of patients with CAS negative were higher than the control group (p ˂0.05). The parameters that correlate most strongly with the clinical activity score were the TMV (r =0.825 p ˂0.001), R-Hertel (r =0.783 p ˂0,001), and area and volume of inferior rectus (r =0.797 ve r =0.755 p ˂0.001, respectively). Retroorbital fat volume was associated with CAS, but the correlation was lower than with EOMs (r = 0.495 p ˂0.001). The areas and volumes of ROR and BO were also strongly correlated with CAS (p ˂0.001). In patients with diplopia, all orbital measurements except orbital fat tissue were higher than in patients without diplopia. Clinically measured Hertel (r = 0.825 p ˂0,001) was very strongly; TMV, all EOMs volumes, area and volume of ROR were strongly; area and volume of ROFT were moderately correlated with R-Hertel. The parameters mostly affecting hertel were TMV, which increased 2.32 mm Hertel with 1 cm3 increase in volumes, and TMV/BOV ratio, which increased 3.72 mm Hertel with 0.1% increase of ratio. The most useful parameters for clinical activity evaluation were medial rectus (MR) volume (81% sensitive, 95% specific, cut-off: 0.90 cm3), TMV (81% sensitive, 88% specific, cut-off: 3.42 cm3), R-Hertel (90% sensitive, 72% specific, cut-off: 23.2 mm), and MR volume/BOV ratio (81% sensitive, 95% specific, cut-off: 0.069). AntiTG level was higher in patients with CAS positive (p = 0.043). There was a moderate correlation between volumes of ROFT and ROR and levels of sT3 and antiTG. Volume of ON and the areas of axial, coronal, and proximal ON were lower in the study group (p <0.05). Clinical activity positively correlated with ON volume (r =0.375 p =0.003) and negatively correlated with axial area of ON (r =-0.324 p =0.012). There was a negative correlation between the proximal area of RBON and ROFT volume (r = -0.732 p ˂0.001) and TMV (r = -0.336 p = 0.009); and between the distal area of RBON and ROFT volume (r = -0.666 p ˂0.001). There was a positive correlation between R-Hertel and RBON volume (r = 0.275, p = 0.034) and a negative correlation between R-Hertel and axial area of ON (r = -0.338, p = 0.008). The area of ON inside optic canal was higher in the study group IX (p = 0.005). There was a negative correlation between the area of ON inside optic canal and the axial area (r = -0.314, p = 0.015) and proximal area (r = -0.334 p = 0.007) of ON. Conclusion: In patients with TAO, area and volume measurements of orbital tissues can be made from orbital MRI using volume rendering technique. Even in the inactive phase of TAO, all orbital tissue areas and volumes increase. The increases of all orbital soft tissue (muscle, fat, total) and BO volumes are correlated with CAS, with muscle volume being more pronounced. The most effective parameters to Hertel measurement are TMV and its ratio to BO. Medial rectus volume, TMV, R-Hertel, and the ratio of MR/BO volume can be used for clinical activity evaluation. Increased soft tissue volume causes compression to the ON, being more prominent in the proximal half. Key Words: Graves' Ophthalmopathy, Magnetic Resonance Imaging, Orbit, Orbital MRI, Thyroid Associated Ophthalmopathy, Volume Rendering Technique.
Objectives: To detect area and volume changes in orbital tissues in thyroid ophthalmopathy by magnetic resonance imaging (MRI) and to evaluate its relationship with clinical activity. Materials and Methods: Thirty patients who had been followed-up with the diagnosis of thyroid associated ophthalmopathy (TAO) between January 2015 and December 2019 in Ondokuz Mayıs University Medical Faculty Hospital, Ophthalmology Clinic and 30 individuals without orbital pathology (as a control group) were included in the study. Patient's data were analyzed retrospectively and recorded. The areas and volumes of extraocular muscles (EOM), retroorbital fat tissue (ROF), retro-orbital region (ROR), bony orbit (BO), retrobulbar optic nerve (RBON), optic nerve (ON) inside the optic canal, and globe were created using the volume rendering technique from magnetic resonance (MRI) images. The volume and area of orbital tissues was calculated using the osirix MD analysis software tool. After the MR images were recorded as digital imaging and communications in medicine (DICOM) in the osirix MD software program, the borders of orbital tissues were manually marked to measure the volume and area. The area and volume of that region were automatically taken. Total muscle volume (TMV) was calculated by summing rectus muscle volumes mathematically. The ratios of orbital tissue areas and volumes were calculated. The amount of exophthalmos was measured and recorded as radiological Hertel (R-Hertel). These measurements were compared with orbital tissue areas, volumes, and ratios created from MRI images of the control group. A comparison between the two eyes was also performed in the study group. In addition, the correlation of orbital measurements with clinical activity score (CAS), presence of diplopia, hertel exophthalmometer measurements, and thyroid function tests were analyzed. Results: Sixty eyes of 30 patients with the mean age of 45.6±11.1 (20-66) years, 15 women and 15 men, were examined in the study group. Sixty eyes of 30 patients with the mean age of 50.3±9.6 (27-63) years, 18 women and 12 men, were examined in the control group. The area and volume of globe were similar between the study and the control groups (p> 0.05). The VIII area and volume of RBON were lower in the study group (p <0,05). The areas, volumes, and ratios of the other orbital tissues were higher in the study group than the control group (p ˂0.05). In the study group, there was no significant difference between the two eyes in clinical measurements, findings and MR measurements, and the involvement was symmetrical. The areas and volumes of EOMs, ROFT, ROR, and BO of patients with CAS negative were higher than the control group (p ˂0.05). The parameters that correlate most strongly with the clinical activity score were the TMV (r =0.825 p ˂0.001), R-Hertel (r =0.783 p ˂0,001), and area and volume of inferior rectus (r =0.797 ve r =0.755 p ˂0.001, respectively). Retroorbital fat volume was associated with CAS, but the correlation was lower than with EOMs (r = 0.495 p ˂0.001). The areas and volumes of ROR and BO were also strongly correlated with CAS (p ˂0.001). In patients with diplopia, all orbital measurements except orbital fat tissue were higher than in patients without diplopia. Clinically measured Hertel (r = 0.825 p ˂0,001) was very strongly; TMV, all EOMs volumes, area and volume of ROR were strongly; area and volume of ROFT were moderately correlated with R-Hertel. The parameters mostly affecting hertel were TMV, which increased 2.32 mm Hertel with 1 cm3 increase in volumes, and TMV/BOV ratio, which increased 3.72 mm Hertel with 0.1% increase of ratio. The most useful parameters for clinical activity evaluation were medial rectus (MR) volume (81% sensitive, 95% specific, cut-off: 0.90 cm3), TMV (81% sensitive, 88% specific, cut-off: 3.42 cm3), R-Hertel (90% sensitive, 72% specific, cut-off: 23.2 mm), and MR volume/BOV ratio (81% sensitive, 95% specific, cut-off: 0.069). AntiTG level was higher in patients with CAS positive (p = 0.043). There was a moderate correlation between volumes of ROFT and ROR and levels of sT3 and antiTG. Volume of ON and the areas of axial, coronal, and proximal ON were lower in the study group (p <0.05). Clinical activity positively correlated with ON volume (r =0.375 p =0.003) and negatively correlated with axial area of ON (r =-0.324 p =0.012). There was a negative correlation between the proximal area of RBON and ROFT volume (r = -0.732 p ˂0.001) and TMV (r = -0.336 p = 0.009); and between the distal area of RBON and ROFT volume (r = -0.666 p ˂0.001). There was a positive correlation between R-Hertel and RBON volume (r = 0.275, p = 0.034) and a negative correlation between R-Hertel and axial area of ON (r = -0.338, p = 0.008). The area of ON inside optic canal was higher in the study group IX (p = 0.005). There was a negative correlation between the area of ON inside optic canal and the axial area (r = -0.314, p = 0.015) and proximal area (r = -0.334 p = 0.007) of ON. Conclusion: In patients with TAO, area and volume measurements of orbital tissues can be made from orbital MRI using volume rendering technique. Even in the inactive phase of TAO, all orbital tissue areas and volumes increase. The increases of all orbital soft tissue (muscle, fat, total) and BO volumes are correlated with CAS, with muscle volume being more pronounced. The most effective parameters to Hertel measurement are TMV and its ratio to BO. Medial rectus volume, TMV, R-Hertel, and the ratio of MR/BO volume can be used for clinical activity evaluation. Increased soft tissue volume causes compression to the ON, being more prominent in the proximal half. Key Words: Graves' Ophthalmopathy, Magnetic Resonance Imaging, Orbit, Orbital MRI, Thyroid Associated Ophthalmopathy, Volume Rendering Technique.
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