Evaluation of the Relationship Between Resistive Index, Elastographic Stiffness, and TIRADS Category in Thyroid Nodules

Abstract

Objective: To investigate the relationship between Doppler-derived resistive index(RI) values, TI-RADS categories, and shear-wave elastography(SWE) parameters in solid thyroid nodules, and to determine whether RI contributes additional value to imaging-based characterization. Material-Methods: This retrospective study included 52 patients with 52 solid thyroid nodules larger than 1 cm. All nodules were evaluated with grayscale ultrasonography, Doppler sonography, and SWE. TI-RADS categories were assigned according to standard B-mode criteria. Vascularity was classified into four Doppler patterns, and RI was measured from intranodular arterial flow in nodules exhibiting pattern 2 or 3 vascularization. SWE measurements included mean shear-wave velocity(Vmean) and velocity standard deviation(Vsd). Associations between RI and demographic(age,sex), morphologic(nodule size,TI-RADS),and elastographic(Vmean,Vsd) variables were analyzed using correlation and nonparametric tests. Histopathology was available only in a limited subgroup and was therefore not used as a primary endpoint. Results: The mean age was 49.28±14.55 years; 88.5% of patients were male. TI-RADS categories were TI-RADS 2 in 19 nodules(36.5%), TI-RADS 3 in 29 nodules(55.8%), and TI-RADS 4 in 4 nodules(7.7%). Mean nodule diameter was 17.06±6.63 mm. Vmean and Vsd were 2.47±0.86 m/s and 0.62±0.39 m/s, respectively. Mean RI was 0.52±0.14. RI showed no significant association with age, sex, nodule side, size, Vmean, or Vsd. Although RI values were slightly higher in TI-RADS≥3 nodules compared to lower TI-RADS categories, this difference was not statistically significant(p=0.054). Conclusion: In this preliminary cohort, RI was not significantly associated with TI-RADS classification or SWE-derived stiffness parameters. These findings suggest that RI offers limited additional diagnostic value beyond conventional ultrasonography and elastography in the structural evaluation of thyroid nodules.

Keywords

• Shear wave elastography
• resistive index
• TIRADS
• Doppler sonography

Tiroid Nodüllerinde Rezistif İndeksi, Elastografik Sertlik ve TIRADS Kategorisi Arasındaki İlişkinin Değerlendirilmesi

Abstract

Amaç: Bu çalışmanın amacı, solid tiroid nodüllerinde Doppler kaynaklı rezistif indeks(RI) değerleri ile TI-RADS kategorileri ve shear-wave elastografi(SWE) parametreleri arasındaki ilişkiyi araştırmak ve RI ölçümlerinin görüntüleme temelli karakterizasyon sürecine ek katkı sağlayıp sağlamadığını belirlemektir. Yöntemler: Bu retrospektif çalışmaya, çapı 1 cm’den büyük olan 52 solid tiroid nodülü bulunan 52 hasta dahil edildi. Tüm nodüller gri skala ultrasonografi, Doppler sonografi ve SWE ile değerlendirildi. TI-RADS sınıflaması standart B-mod kriterlerine göre yapıldı. Vaskülarite dört Doppler paterni şeklinde sınıflandırıldı ve RI ölçümü, patern 2 veya 3 intranodüler arteriyel akım gösteren nodüllerden elde edildi. SWE ölçümleri ortalama shear-wave hızı(Vmean) ve hız standart sapması(Vsd) parametrelerini içeriyordu. RI ile demografik(yaş, cinsiyet), morfolojik(nodül boyutu, TI-RADS) ve elastografik(Vmean, Vsd) değişkenler arasındaki ilişkiler korelasyon ve non-parametrik testler ile analiz edildi. Histopatolojik doğrulama yalnızca sınırlı bir alt grupta mevcut olduğundan birincil sonlanım noktası olarak kullanılmadı. Bulgular: Hastaların ortalama yaşı 49.28±14.55 yıl olup %88.5’i erkekti. TI-RADS dağılımı TI-RADS 2 için 19 nodül(%36.5), TI-RADS 3 için 29 nodül(%55.8) ve TI-RADS 4 için 4 nodül(%7.7) şeklindeydi. Ortalama nodül çapı 17.06±6.63 mm idi. Vmean ve Vsd sırasıyla 2.47±0.86 m/sn ve 0.62±0.39 m/sn olarak ölçüldü. Ortalama RI değeri 0.52±0.14 idi. RI; yaş, cinsiyet, nodül tarafı, nodül boyutu, Vmean veya Vsd ile anlamlı bir ilişki göstermedi.TI-RADS≥3 nodüllerde RI değerlerinin daha yüksek olması eğilimi izlense de bu fark istatistiksel olarak anlamlı değildi(p=0.054). Sonuç: Bu çalışmada RI değerleri ile TI-RADS sınıflaması veya SWE kaynaklı sertlik parametreleri arasında anlamlı bir ilişki saptanmadı. Bulgular, tiroid nodüllerinin yapısal değerlendirilmesinde RI’ın konvansiyonel ultrasonografi ve elastografi yöntemlerine ek sınırlı tanısal katkı sağladığını düşündürmektedir.

Keywords

• Shear-wave elastografi
• rezistif indeks
• TI-RADS
• Doppler sonografi.

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