Hello, I'm Dr. Lauren Gratian. I'm a clinical endocrinologist at Duke Medical Center. And I'm going to be talking you through a step-by-step method for reading pituitary MRIs. In step one, we will review coronal and sagittal images to determine the size and shape of the lesion. In step two, we will describe the location of the mass within the cella and determine if the mass is extending outside of the cella and compressing or invading surrounding structures. Finally, in step three, we will review the pre- and post-contrast T1-weighted images to determine the signal intensity and contrast enhancement patterns of the mass. This will help to narrow our differential diagnosis. Let's get started. In the first step, we will report the size of the mass. Here, we have a coronal T1-weighted post-contrast image of the cella. And we see a rounded lesion located in the right aspect of the pituitary gland. This measures 8.9 millimeters in the cranial caudal dimension and 9.5 millimeters in the transverse dimension. Next, we review the sagittal image of the same lesion to determine the anterior-posterior dimension of the mass. In this case, this measures 8.9 millimeters. And of note, you can also measure the cranial caudal dimension from the sagittal view. In step two, we will describe the location of the lesion and note any extension outside of the cella. In this case, we have a pre- and post-contrast T1-weighted coronal image. We see a small lesion, which measures 4 by 5 millimeters in size. It is located in the left inferior portion of the pituitary gland. It does not extend outside of the cella or expand to the normal structure of the cella. In this example, we have a sagittal and coronal T1-weighted images taken post-contrast. We see a large lesion, which measures approximately 2.7 by 3.4 by 3.6 centimeters. The pituitary fossa is enlarged with an expanded cella surrounded by thin remodeled bone, which is marked by the orange line. This suggests a slow-growing mass. The lesion extends to the supercellar space, causing compression and superior displacement of the optic chiasm, which is marked by the blue arrow. In this example, we have a coronal T1-weighted image post-contrast. Figure A and B are the same image. Figure B has been annotated to highlight the outline of the lesion in blue, which extends into the supercellar cistern superiorly and abuts the optic nerves. This is marked by the red arrow. The mass also extends laterally on the right side. There is partial encasement of the right side and partial encasement of the right cavernous internal carotid artery, which is noted in yellow, but there is no significant narrowing of the artery. This mass may be invading the right cavernous sinus. The most convenient method to determine cavernous sinus invasion on MRI is to assess the degree of encasement of the cavernous portion of the internal carotid artery. 60 degrees makes involvement of the sinus very unlikely, whereas greater than 270 degrees makes involvement almost certain. In step three, we review the pre- and post-contrast T1- weighted images to determine signal intensity and contrast enhancement of the lesion. When viewing the non-contrasted image, note whether the mass is iso-intense, hypo-intense, or hyper-intense compared to the gray matter of the brain. When viewing the post-contrasted image, note whether the mass enhances relative to the surrounding tissue. And if so, is that enhancement homogenous? Here, we have the same lesion we reviewed in the previous slide. Figure A is taken pre-contrast and demonstrates the lesion is iso-intense to gray matter. Figure B is taken post-contrast, and we see that the lesion does not enhance or is hypo-enhancing compared to the surrounding pituitary tissue. This is typical of an adenoma. And the post-contrast image helps us to better discern the boundaries of the adenoma. In this example, we have a pre- and post-contrast sagittal view of the cella. In figure A, we see a small posterior lesion, which is hypo-intense compared to gray matter of the brain. In figure B, we note that the lesion does not enhance with contrast. This finding is most consistent with a cystic lesion. In this slide, we again are viewing T1-weighted sagittal images pre- and post-contrast. In figure A, we see a small lesion located in the posterior aspect of the pituitary gland, which is hyper-intense compared to the gray matter of the brain. In figure B, we note that the lesion is hypo-enhancing compared to surrounding normal pituitary tissue. There are only a few substances that appear hyper-intense on T1 non-contrasted images. These include blood, protein, fat, calcification, and the normal posterior right spot. Therefore, the differential diagnosis for this lesion includes a Rathke's cleftus, proteinaceous content, or a hemorrhagic adenoma. Thank you.

pituitary MRI

reading method

lesion size

mass location

differential diagnosis