title: MR signal change in venous thrombus relates organizing process and thrombolytic response in rabbit.
abstract: Venous thrombus is subsequently organized and replaced by fibrous connective tissue. However, the sequential changes in venous thrombi are not reliably detected by current noninvasive diagnostic techniques. The purpose of this study is to reveal whether magnetic resonance (MR) can detect venous thrombus, define thrombus age and predict thrombolytic responses. Thrombus in the rabbit jugular vein was imaged with a 1.5-T MR system at 4 h and at 1, 2 and 4 weeks using three-dimensional (3D) fast asymmetric spin echo T2-weighted (T2W) and 3D-gradient echo T1-weighted (T1W) sequences. The jugular veins were histologically assessed at each time point. Magnetic resonance imaging (MRI) was also performed in vivo before and 30 min after tissue plasminogen activator (t-PA) administration. The thrombi in MRI were comparable in size to histological sections. The signal intensity (SI) of thrombi at 4 h was heterogeneously high or low on T2W or T1W images, respectively. The SI of thrombi on T2W images decreased time-dependently, but increased on T1W images at 1 and 2 weeks. Morphological analysis showed time-dependent decreases in erythrocyte, platelet and fibrin areas and time-dependent increases in smooth muscle cell, macrophage, collagen and iron areas. The t-PA administration significantly decreased thrombus volume at 4 h but not at 1, 2 and 4 weeks. Venous thrombosis can be reliably and noninvasively detected by MRI. Measurement of SI might support assessments of thrombus age and thrombolytic response.
authors.affiliation: Department of Radiological Technology, Koga General Hospital, Miyazaki, Japan.
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Kuroiwa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamashita
authors.forename: Tosiaki
authors.initials: T
authors.lastname: Miyati
authors.forename: Eiji
authors.initials: E
authors.lastname: Furukoji
authors.forename: Misaki
authors.initials: M
authors.lastname: Takahashi
authors.forename: Toshiya
authors.initials: T
authors.lastname: Azuma
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sugimura
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Asanuma
authors.forename: Shozo
authors.initials: S
authors.lastname: Tamura
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kawai
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Asada
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000166:cytology; D004912:Erythrocytes / Q000166:cytology; D005337:Fibrin / Q000378:metabolism; D006801:Humans; D021621:Imaging, Three-Dimensional; D007601:Jugular Veins / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D011817:Rabbits; D012815:Signal Processing, Computer-Assisted; D013927:Thrombosis / Q000473:pathology*; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000378:metabolism; D020246:Venous Thrombosis / Q000473:pathology*
chemical_list: D005337:Fibrin; D010959:Tissue Plasminogen Activator