MRI ADRENAL GLAND

Adrenal  MRI without contrast Sequences

Indications: adrenal adenomas versus malignancy. 

• Coronal HASTE: hepatic dome to iliac crests. 
• Axial 2-D FLASH in-phase
• Axial 2-D FLASH out-of-phase
• Axial 2-D FLASH subtraction images.
• GRE T1 In-phase & Out of phase axial
• OptionalT2 FSE fat sat axial
• GRE T1 fat sat axial

Post Contrast Adrenal  MRI

•  Immediate post contrast transverse Spoiled Gradient echo image.
• One-minute post gadolinium Spoiled Gradient echo transverse image.
• Post-contrast fat suppressed transverse Spoiled Gradient echo image.

(In some places dynamic adrenal post contrast used to do and including  a 10 min fat-sat coronal sequence )

Technical notes:

• Coronal HASTE: survey sequence with heavy T2 weighting.
• Axial 2-D FLASH: in-phase, out-of-phase images acquired as a double echo to minimize misregistration for the subtraction images.  Acquire from hepatic dome to bottom of kidneys.
• If other abdominal findings (ie., liver lesions) also need to be worked up concomitantly, perform abdomen survey instead, as adrenal workup sequences are incorporated into that protocol.

Dictation template:

Coronal HASTE, axial 2-D FLASH in- and out-of-phase with subtractions from the hepatic dome to the iliac crests. 

MR evaluation of the adrenal glands is rapid and accurate. MR is more specific than spiral CT for characterization of adrenal adenomas. Adrenal MR studies are performed rapidly and are very specific. 

Use of opposed-phase technique with a single in-phase followed by an out of phase series takes less than 5 minutes of “table time“ and can characterize adenomas with a greater than 95% specificity and sensitivity.
Using opposed-phase techniques, adenomas lose signal intensity by 10% or more between in and out of phase images. All imaging parameters, except for the TE, must be identical (i.e. the same TR, fov, slice
thickness, gap, bandwidth, flip angle etc). Opposed-phase Imaging Technique
• Use standard T1-weighted GRE  images.
• Incremental TE change makes the sequence in-phase or out-of-phase.
• Fat and water have different resonance frequencies. 
• When imaged “out of phase“ fat and water signals interfere destructively. 
• Used to depict areas of hepatic steatosis and adrenal adenomas.
Because the adrenal glands are thin structures, and adrenal lesions may be quite small, thin sections are optimal when performing adrenal MRI. We normally use 4- mm slices for imaging. Fat saturation is both
useful and can be a hindrance. The retroperitoneal fat provides for good internal contrast and makes the adrenals easy to see, so suppression of the fat with fat saturation may actually make it more
difficult to visualize subtle abnormalities. However, if one wants to prove that a lesion
in the adrenals contains fat, then it is best to perform a T1 GRE series with and without fat
saturation, any bulk fat containing lesions, such as a myolipoma, will lose signal on the
fat-saturated series. T2-weighted images are useful when evaluating other adrenal lesions, such as
cysts, hemorrhage, and pheocromcytomas. Therefore as a standard adrenal protocol,
we include T2-weighted images, even though they are not helpful for the most common indication for adrenal MRI; characterization of adrenal adenomas Sample Adrenal MR Protocol Sequence Plane