Measurement of Cardiac Iron Load with MRI in Thalassemia Major Patients, Evaluation of the Effect of Iron Load on Cardiac Functions, and Comparison with Tissue Doppler

Öz

Aim: Thalassemia major (TM) patients typically suffer from iron overload due to regular blood transfusions, with cardiac complications representing the primary causes of morbidity and mortality in TM. Magnetic resonance imaging (MRI) has gained prominence in the quantitative assessment of myocardial iron overload. However, the quantification of cardiac iron using 3 Tesla MRI has not been thoroughly explored in existing literature. This study aims to quantify cardiac iron load using 3T MRI, employing the T2* relaxation technique, and to investigate the association between cardiac T2* values and liver T2* values, serum ferritin levels, as well as systolic and diastolic functions assessed by echocardiography (ECHO) and MRI. Method: Transthoracic echocardiography (TTE) was performed on 21 TM patients (13 females, 8 males; mean age 29.3±7.6) and 11 healthy volunteers (5 females, 6 males; mean age 32.4±5.9) by the cardiology department. Within one week following the TTE, a 16-echo T2* gradient Turbo Field Echo (TFE) sequence was used in a 3T MRI device to assess cardiac and liver iron load. Short-axis cine images were obtained using a 2D-Balanced (steady-state free precession)-TFE sequence for the evaluation of cardiac functions. Results: Of the 21 TM patients, 6 showed cardiac T2* values below 12 ms. No significant difference was observed between TM patients with and without cardiac iron accumulation in terms of liver T2* values, serum ferritin levels, and parameters used to evaluate systolic and diastolic functions in TTE and MRI (p>0.05). Additionally, no significant correlation was found between cardiac T2* values and all other measured parameters (p>0.05). A moderate negative correlation was detected between serum ferritin levels and liver T2* values (r = -0.663). No signs favoring systolic or diastolic dysfunction were found in TTE. Conclusion: The parameters measured in TTE and CMRI, serum ferritin levels, and liver T2* values do not have a role in predicting cardiac iron load. The cardiac T2* value should be used in the monitoring of cardiac iron accumulation and chelation therapy in TM patients.

Anahtar Kelimeler

• Thalassemia major
• magnetic resonance imaging
• iron overload

Talasemi Majör Hastalarında MRG ile Kardiyak Demir Yükü Ölçümü, Demir Yükünün Kardiyak Fonksiyonlara Etkisinin Değerlendirilmesi ve Doku Doppleri ile Karşılaştırılması

Öz

Amaç: Talasemi majör (TM) hastalarında, düzenli kan transfüzyonları nedeniyle demir birikimi görülmektedir. TM hastalarında morbidite ve mortalitenin en sık nedeni artan demir birikimine bağlı gelişen kardiyak komplikasyonlardır. Kardiyak demir birikimi manyetik rezonans görüntüleme (MRG) ile doğru bir şekilde ölçülebilmektedir. Ancak 3 Tesla (3T) MRG ile gerçekleştirilmiş yeterince çalışma bulunmamaktadır. Bu çalışmanın amacı, kardiyak demir birikimini 3T MRG cihazında T2* relaksasyon tekniği ile ölçmek ve kardiyak T2* değerleri ile karaciğer T2* değerlerinin, serum ferritin seviyesinin, ekokardiyografi ve kardiyak MRG (KMRG)’de sistolik ve diyastolik fonksiyonları değerlendirmek için ölçülen parametrelerin ilişkisini araştırmaktır. Yöntem: 21 TM hastasına (13 kadın, 8 erkek; ortalama yaş 29,3±7,6) ve 11 sağlıklı gönüllüye (5 kadın, 6 erkek; ortalama yaş 32,4±5,9) kardiyoloji departmanı tarafından transtorasik ekokardiyografi (TTE) yapıldı. TTE’den sonra bir hafta içerisinde kardiyak ve karaciğer demir yükünü değerlendirmek için 3T MRG cihazında 16 ekolu T2* gradiyent Turbo Field Echo (TFE) sekansı kullanıldı. Kardiyak fonksiyonları değerlendirmek amacı ile 2D-Balanced (steady-state free precession)-TFE sekansı ile kısa aks sine görüntüler alındı. Bulgular: 21 TM hastasının 6’sında kardiyak T2* değeri 12 msn altında ölçüldü. Kardiyak demir birikimi olan ve olmayan TM hastalarında karaciğer T2* değeri, serum ferritin düzeyi, TTE ve MRG’de sistolik ve diyastolik fonksiyonların değerlendirilmesinde kullanılan parametreler arasında anlamlı fark saptanmadı (p>0,05). Ayrıca kardiyak T2* değeri ile ölçülen diğer tüm parametreler arasında anlamlı korelasyon ilişkisi bulunmadı (p>0,05). Serum ferritin düzeyi ile karaciğer T2* değeri arasında orta düzeyde negatif korelasyon saptandı (r = -0,663). TTE’de sistolik veya diyastolik disfonksiyon lehine bulgu bulunmadı. Sonuç: Kardiyak demir yükünü öngörmede TTE ve KMRG’de ölçülen parametrelerin, serum ferritin düzeyinin ve karaciğer T2* değerinin yeri bulunmamaktadır. TM hastalarının kardiyak demir birikimi ve birikime yönelik şelasyon tedavisi takibinde kardiyak T2* değeri kullanılmalıdır.

Anahtar Kelimeler

• Talasemi majör
• manyetik rezonans görüntüleme
• demir aşırı yükü

Kaynakça

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