Purpose: To assess the performance of a three-dimensional (3D) non-contrast respiratory-triggered steady state free precession (SSFP) pulse sequence for detection of renal artery stenosis.
Materials and Methods:A total of 64 patients who had non-contrast MR angiography (NC MRA) and 3D contrastenhanced MRA (CE MRA) performed during the same exam and three patients who had NC MRA followed by conventional catheter angiography within one month of the MRI exam were included in this retrospective study. Two blinded readers evaluated NC MRA images for the presence of significant renal artery stenosis and also rated their diagnostic confidence and evaluated the images for artifact. A similar analysis was performed for CE MRA images by two additional blinded readers, and discrepancies were resolved by consensus reading.
Results:The 67 patients had 168 main and accessory renal arteries, with significant (>50%) stenosis in 34 arteries on CE MRA or conventional angiography. The two NC MRA readers had sensitivity and specificity for detection of significant stenosis of 94%/82% and 82%/87% respectively on a per renal artery basis.
Conclusion:There was good agreement between CE MRA and NC MRA for detection of significant renal artery stenosis. This technique should prove useful in evaluating patients with suspected renovascular hypertension who are unable to undergo CE MRA. THREE-DIMENSIONAL gadolinium contrast-enhanced MR angiography (CE MRA) is a sensitive and accurate technique for detection of renal artery stenosis, and is useful as a primary or confirmatory non-invasive test in patients with suspected renal artery stenosis (1-5). Recent reports linking the use of gadolinium-based MR contrast agents with nephrogenic systemic fibrosis (NSF) (6-9), however, have led to a dramatic reduction in the number of renal MRA exams ordered and performed, since many patients with refractory hypertension and suspected renal artery stenosis also have renal insufficiency.While duplex sonography is effective in many patients, complete visualization of the renal arteries can be limited. Computed tomography (CT) angiography involves the use of iodinated contrast, also problematic in patients with renal insufficiency, and requires ionizing radiation. This state of affairs has stimulated many attempts to reinvestigate non-contrast MRA (NC MRA) methods. While phase contrast and time-of-flight MRA pulse sequences have proven useful in assessment of the renal arteries in previous investigations, they have limitations as a primary technique for non-contrast renal MRA (10-13); more recent investigations have focused predominantly on modified steady state free precession (SSFP) pulse sequences. SSFP sequences are attractive for their high vascular signal to noise ratio, fairly rapid acquisition times, and inherent flow compensation (14-26). Modifications of the basic 3D SSFP pulse sequence for improved visualization of the renal arteries have included arterial spin labeling (14,15), navigator or respiratory gating (14,15,17,18,(20)(21)(22)(23)(24), ...
T riple-negative breast cancer (TNBC) accounts for about 10%-20% of all breast cancers, and it is negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (1). Compared with other types of breast cancer, TNBC is considered more aggressive, with a higher recurrence rate and decreased overall survival (1,2). Within the TNBC group, pathologic complete response (pCR) to neoadjuvant systemic therapy (NAST) is strongly correlated with improved disease-free survival and overall survival (3). Because only about 20%-50% of participants with TNBC will achieve pCR, early assessment of the treatment response is beneficial (4-6). For example, participants with predicted non-pCR may be directed toward more aggressive or potentially more effective novel therapies at an early stage.The effectiveness of NAST is most commonly assessed by the change in tumor size based on conventional breast imaging (eg, mammography, US) and clinical examination (7). The appropriateness criteria of the American
Purpose: To depict supraaortic arteries using (3D fast spin echo (FSE) combined with slab selective inversion recovery for noncontrast magnetic resonance angiography (MRA) in healthy volunteers, and to investigate the property of the inflow enhanced inversion recovery FSE (IFIR-FSE) for background suppression and inflow effects.Materials and Methods: IFIR-FSE with no image subtraction was used to visualize the aortic arch, subclavian arteries, carotid arteries, and vertebral arteries in 10 healthy volunteers. Simulations were performed to achieve both high background suppression and inflow effects by adjusting the inversion time (TI) and wait time after data acquisition. The effect of inflow was investigated with TIs of 800, 1200, 1600, and 2000 msec. Contrast between artery and these background tissues were measured with scan protocols based on simulation results.Results: IFIR-FSE images showed good visualization of the supraaortic arteries and allowed separation of arteries from veins without image subtraction. The proposed method demonstrated that a high contrast between arteries and background tissues can be acquired with various TIs, which was in good agreement with the simulation. A TI over 1600 msec was favorable in terms of background suppression, arterial signal intensity, and inflow effects.
Conclusion:Inflow enhanced inversion recovery cardiactriggered 3D FSE imaging can be used for supraaortic artery imaging without contrast agents.
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