Comparative Analysis of FSE T2 Weighted, Chemical Shift and Dynamic Contrast-Enhanced MR Imaging in the Characterization of Adrenal Masses Based on Qualitative and Quantitative Parameters

Objectives: The purpose of our study was to investigate the role of different magnetic resonance imaging (MRI) parameters in the characterization of adrenal masses.
Methods: A total of 150 patients who presented with 186 adrenal tumors were retrospectively evaluated in this study. Final patient cohort consisted of 17 pheochromocytomas, 3 adrenocortical carcinomas, 24 metastases, 31 lipid-poor adenomas and 111 lipid-rich adenomas. We carried out a visual assessment on FSE (Fast spin echo)T2 weighted images and also calculated T2 signal intensity ratio of all adrenal masses and also performed a qualitative assessment on chemical shift imaging (CSI) together with quantitative calculation using Adrenal to spleen signal intensity (si) ratio and Adrenal si index formulas. On dynamic contrast-enhanced sequences, visual assessment based on enhancement patterns on late-arterial phase images was performed and also mean signal intensity measurements were carried out. All examinations were interpreted by two abdominal radiologists in consensus who were blinded to the clinical and pathological findings. Statistical analysis was performed.
Results: On FSE T2 weighted imaging, isointense to liver and slightly hyperintense than liver was found higher in benign cases, however, in malignant cases moderately and strikingly hyperintense than liver was higher than in benign cases (p=0.001, p<0.01). There was a statistically significant difference between the T2 signal intensity ratio values of adrenal tumor groups (p=0.001, p<0.01). In lipid-rich and lipid-poor adenoma groups, T2 signal intensity ratio values was significantly lower than in pheochromo-cytoma and metastasis cases. In malignant group, T2 signal intensity ratio values were found statistically significantly higher than in the benign group (p=0.001, p<0.01). There was a statistically significant difference between CSI visual assessment of adrenal tumor groups (p=0.001, p<0.01). Although moderate and significant signal intensity loss was usually detected in lipid-rich adenoma group, never detected in other tumor groups. There was also a statistically significant difference between benign and malignant adrenal tumor groups (p=0.001, p<0.01). In the malignant group, Adrenal to spleen si ratio values were found significantly higher whereas, Adrenal si index values were significantly lower compared to benign tumors (p=0.001, p<0.01). Based on malignancy, there was a statistically significant difference between adrenal tumor groups (p=0.001, p<0.01). Although capillary blush and homogenous type enhancement were more common in benign cases than in malignant ones, peripheral-patchy and strikingly capillary blush type enhancement was more frequent in malignant tumors. Based on malignancy, mean arterial signal intensity values of malignant tumors were statistically higher than benign tumors (p=0.001; p<0.01).
Conclusion: Dynamic contrast-enhanced MRI protocol including CSI aids in the characterization of indeterminate adrenal masses. Herein, the combined use of qualitative and quantitative parameters enables more tumors to be recognized that otherwise would be indeterminate.

Adrenal Kitlelerin Karakterizasyonunda Kalitatif ve Kantitatif Parametreler Temel Alýnarak FSE T2 Aðýrlýklý, Kimyasal Faz ve Dinamik Kontrastlý Manyetik Rezonans Görüntülemenin Karþýlaþtýrmalý Analizi

Amaç: Çalýþmamýzýn amacý, adrenal kitlelerin karakterizasyonunda farklý manyetik rezonans görüntüleme (MRG) parametrelerinin rolünü araþtýrmaktý.
Yöntem: Bu çalýþmada 150 hastada toplam 186 adrenal tümör retrospektif olarak deðerlendirildi. Sonuç hasta popülasyonu 17 feokromositoma, 3 adrenokortikal karsinoma, 24 metastaz, 31 lipid fakir adenoma ve 111 lipid zengin adenomadan oluþmaktaydý. Çalýþmamýzda FSE (Hýzlý spin eko)T2 aðýrlýklý görüntülerde görsel deðerlendirme gerçekleþtirdik ve ayrýca T2 sinyal intensite oranýný hesapladýk ve kimyasal faz görüntüleme ile, kalitatif deðerlendirme ve Adrenal- dalak sinyal intensite oraný and Adrenal sinyal intensite indeks formüllerini kullanarak kantitatif hesaplamalar yaptýk. Dinamik kontrastlý sekanslarda, geç arteriyal faz görüntülerde, kontrastlanma paternini görsel olarak deðerlendirdik ve ayrýca ortalama sinyal intensite ölçümlerini yaptýk. Tüm deðerlendirmeler klinik ve patoloji sonuçlarýný bilmeyen iki abdomen radyoloðu tarafýndan konsensüsa varýlarak yorumlandý. Ýstatistiksel analiz gerçekleþtirildi.
Bulgular: FSE T2 aðýrlýklý görüntülerde, karaciðer ile izointens ve karaciðere göre hafif derecede hiperintens olma durumu benign olgularda daha sýk görülürken, malign olgularda karaciðerden orta derecede veya belirgin derecede hiperintens olma durumu daha sýk görüldü (p = 0.001, p< 0.01). Adrenal tümör gruplarý arasýnda T2 sinyal intensite oraný deðerleri bakýmýndan istatistiksel olarak anlamlý fark saptandý (p = 0.001, p< 0.01). Lipid zengin ve lipid fakir adenoma gruplarýnda, T2 sinyal intensite oraný deðerleri feokromositoma ve metastaz olgularýndan anlamlý derecede düþüktü. T2 sinyal intensite oraný deðerleri, malign olgularda benign olgulara göre istatistiksel olarak önemli derecede yüksek bulundu (p = 0.001, p< 0.01). Kimyasal faz görüntüleme ile görsel deðerlendirmede, adrenal tümör gruplarý arasýnda istatistiksel olarak anlamlý fark saptandý (p = 0.001, p< 0.01). Lipid zengin adenoma grubundaki hastalarda genellikle orta derecede ve belirgin sinyal intensite kaybý saptanmasýna karþýn, diðer tümör gruplarýnda bu bulguya rastlanmadý. Benign ve malign adrenal tümör gruplarý arasýnda istatistiksel olarak anlamlý fark saptandý (p = 0.001, p< 0.01). Malign gruptaki tümörlerde, Adrenal-dalak sinyal intensite oraný deðerleri benign gruptaki tümörlere göre belirgin derecede yüksek olmasýna karþýn, Adrenal sinyal intensite indeks deðerleri benign gruba göre belirgin derecede düþük bulundu. Maliginite açýsýndan adrenal tümör gruplarý arasýnda istatistiksel olarak anlamlý fark saptandý (p = 0.001, p< 0.01). Benign olgularda, kapiller blush ve homojen tip kontrast tutulumu daha sýk görülmesine karþýn, periferal-yamalý ve belirgin kapiller blush kontrast tutulumu malign olgularda daha sýk görüldü. Malign tümörlerin arteriyal sinyal intensite deðerleri benign tümörlere göre istatistiksel olarak anlamlý derecede yüksek bulundu (p=0,001; p<0,01).
Sonuç: Kantitatif parametrelerin kombine olarak kullanýlmasý, aksi takdirde kararsýz kalýnacak olan daha fazla adrenal tümörün taný almasýný mümkün kýlar. (SETB-2023-08-152)