[Visualization of Four Intracranial Stents and In-stent Stenosis with Stenotic Models by 3D-TOF-MRA]

In recent years, various types of stents are deployed for the treatment of intracranial artery stenosis and aneurysms. Digital subtraction angiography has been considered to be the gold standard for the follow-up study. However, magnetic resonance angiography (MRA) is less invasive and the recent advances may contribute to the imaging of patients with intracranial stents. Then, a phantom study was carried out to evaluate the MR lumen visibility with these stents. Four stents [low-profile visualized intraluminal support (LVIS), Neuroform Atlas, Neuroform EZ, and Enterprise 2] were placed into plastic tubes with 3 mm inner diameter, and fixed in a container filled with agar. Time-of-flight MRA (TOF-MRA) was performed for these stents, and the signal intensities inside and outside the stents were measured on ImageJ software. Furthermore, 25%, 50%, and 75% stenosis models were created and passed through these stents to evaluate the diagnostic accuracy of in-stent stenosis. The signal intensity inside the LVIS stent was the highest among the four stents (P<0.001), and no significant difference was found between the signal intensities inside and outside the LVIS stent. The diagnostic accuracy with LVIS was also higher than that of Enterprise 2 (P<0.001). In conclusion, the visibility with LVIS indicates that TOF-MRA could be reliably utilized as a diagnostic tool for the detection of in-stent stenosis.