Noncontrast‐enhanced renal angiography using multiple inversion recovery and alternating TR balanced steady‐state free precession

Dong, Hattie Z.; Worters, Pauline W.; Wu, Holden H.; Ingle, R. Reeve; Vasanawala, Shreyas S.; Nishimura, Dwight G.

doi:10.1002/mrm.24480

Cited by 2 publications

(1 citation statement)

References 28 publications

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“…The term TIR is also used in angiography to describe the use of two non-slice-selective inversion pulses to null tissue signals over a wide range of T 1 values and selectively show them with a low or zero background (20,21), together with a slice selective inversion pulse to reinvert in-flowing blood.…”

Section: The Tir Sequence For Angiographymentioning

confidence: 99%

Use of Multiplied, Added, Subtracted and/or FiTted Inversion Recovery (MASTIR) pulse sequences

Fan

Shao

et al. 2020

Quant Imaging Med Surg

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The group of Multiplied, Added, Subtracted and/or fiTted Inversion Recovery (MASTIR) pulse sequences in which usually two or more inversion recovery (IR) images of different types are combined is described, and uses for this type of sequence are outlined. IR sequences of different types can be multiplied, added, subtracted, and/or fitted together to produce variants of the MASTIR sequence. The sequences provide a range of options for increasing image contrast, demonstrating specific tissues and fluids of interest, and suppressing unwanted signals. A formalism using the concept of pulse sequences as tissue property filters is used to explain the signal, contrast and weighting of the pulse sequences with both univariate and multivariate filter models. Subtraction of one magnitude reconstructed IR image from another with a shorter TI can produce very high T 1 dependent positive contrast from small increases in T 1 . The reverse subtracted IR sequence can provide high positive contrast enhancement with gadolinium chelates and iron deposition which decrease T 1 . Additional contrast to that arising from increases in T 1 can be produced by supplementing this with contrast arising from concurrent increases in ρ m and T 2 , as well as increases or decreases in diffusion using subtraction IR with echo subtraction and/or diffusion subtraction. Phase images may show 180º differences as a result of rotating into the transverse plane both positive and negative longitudinal magnetization. Phase images with contrast arising in this way, or other ways, can be multiplied by magnitude IR images to increase the contrast of the latter. Magnetization Transfer (MT) and susceptibility can be used with IR sequences to improve contrast. Selective images of white and brown adipose tissue lipid and water components can be produced using different TIs and in and out-of-phase TEs. Selective images of ultrashort and short T 2 tissue components can be produced by nulling long T 2 tissue components with an inversion pulse and subtraction of images with longer TEs from images with ultrashort TEs. The Double Echo Sliding IR (DESIRE) sequence provides images with a wide range of TIs from which it is possible to choose values of TI to achieve particular types of tissue and/or fluid contrast (e.g., for subtraction with different TIs, as described above, and for long T 2 tissue signal nulling with UTE sequences). Unwanted tissue and fluid signals can be suppressed by addition and subtraction of phase-sensitive (ps) and magnitude reconstructed images. The sequence also offers options for synergistic use of the changes in blood and tissue ρ m , T 1 , T 2 /T 2 *, D* and perfusion that can be seen with fMRI of the brain. In-vivo and ex-vivo illustrative examples of normal brain, cartilage, multiple sclerosis, Alzheimer's disease, and peripheral nerve imaged with different forms of the MASTIR sequence are included.

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Section: The Tir Sequence For Angiographymentioning

confidence: 99%

Use of Multiplied, Added, Subtracted and/or FiTted Inversion Recovery (MASTIR) pulse sequences

Fan

Shao

et al. 2020

Quant Imaging Med Surg

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Magnetic Resonance Angiography of the Thoracic Vasculature: Technique and Applications

Ludwig

Shetty

Broncano

et al. 2020

Magnetic Resonance Imaging

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Magnetic resonance angiography (MRA) is a powerful clinical tool for evaluation of the thoracic vasculature. MRA can be performed on nearly any magnetic resonance imaging (MRI) scanner, and provides images of high diagnostic quality without the use of ionizing radiation. While computed tomographic angiography (CTA) is preferred in the evaluation of hemodynamically unstable patients, MRA represents an important tool for evaluation of the thoracic vasculature in stable patients. Contrast‐enhanced MRA is generally performed unless there is a specific contraindication, as it shortens the duration of the exam and provides images of higher diagnostic quality than noncontrast MRA. However, intravenous contrast is often not required to obtain a diagnostic evaluation for most clinical indications. Indeed, a variety of noncontrast MRA techniques are used for thoracic imaging, often in conjunction with contrast‐enhanced MRA, each of which has a differing degree of reliance on flowing blood to produce the desired vascular signal. In this article we review contrast‐enhanced MRA, with a focus on contrast agents, methods of bolus timing, and considerations in imaging acquisition. Next, we cover the mechanism of contrast, strengths, and weaknesses of various noncontrast MRA techniques. Finally, we present an approach to protocol development and review representative protocols used at our institution for a variety of thoracic applications. Further attention will be devoted to additional techniques employed to address specific clinical questions, such as delayed contrast‐enhanced imaging, provocative maneuvers, electrocardiogram and respiratory gating, and phase‐contrast imaging. The purpose of this article is to review basic techniques and methodology in thoracic MRA, discuss an approach to protocol development, and illustrate commonly encountered pathology on thoracic MRA examinations.Level of Evidence5Technical Efficacy Stage3

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Noncontrast‐enhanced renal angiography using multiple inversion recovery and alternating TR balanced steady‐state free precession

Cited by 2 publications

References 28 publications

Use of Multiplied, Added, Subtracted and/or FiTted Inversion Recovery (MASTIR) pulse sequences

Use of Multiplied, Added, Subtracted and/or FiTted Inversion Recovery (MASTIR) pulse sequences

Magnetic Resonance Angiography of the Thoracic Vasculature: Technique and Applications

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