MRI Pituitary/Sella — Dictation, Appropriateness, and Dose for Residents
1. The Hook — That Subtle Hypoenhancing Focus
Endocrinology just called. Again. They have a patient with classic signs of Cushing’s disease, and the labs point to an Adrenocorticotropic Hormone (ACTH)-secreting pituitary source. The case is on your list: MRI Brain Pituitary, dynamic contrast-enhanced. Your attending is going to walk by in an hour and ask one question: “See the microadenoma?” This isn’t about finding a giant mass compressing the optic chiasm; it’s about spotting a 4 mm, slowly enhancing lesion that only shows up for about 60 seconds on one specific sequence. Miss it, and the patient might get a negative read and an unnecessary, invasive petrosal sinus sampling procedure.
When I was a fellow, the pituitary dynamic was one of those studies where the entire diagnostic value hinged on getting the timing right and knowing exactly where to look. It’s a high-stakes read. Getting the key findings into a clean, structured report shows the attending you know what matters. For more high-yield guides like this, check out the residents and fellows resource hub we’ve put together.
2. What an MRI of the Brain and Pituitary Covers and What Attendings Look For
A dedicated pituitary MRI isn’t a general brain scan. It uses a small field of view, thin slices, and a critical dynamic contrast-enhanced (DCE) sequence to zero in on the sella turcica. The primary goal is to find and characterize tiny pituitary adenomas that are invisible on standard brain MRIs. Endocrinologists order this study for a focused set of problems, and your report needs to answer their specific questions.
Common indications you’ll see:
- Workup for Cushing’s disease (ACTH-secreting microadenoma) or acromegaly (GH-secreting adenoma)
- Hyperprolactinemia, galactorrhea, or amenorrhea
- Visual field defects, especially bitemporal hemianopia suggesting optic chiasm compression
- Central diabetes insipidus (to evaluate the pituitary stalk and posterior bright spot)
- Suspected pituitary apoplexy (acute headache and vision loss)
Your attending expects a report that systematically evaluates the key structures and addresses the core clinical question. They’ll be looking for your assessment of the gland size, stalk position, optic chiasm, cavernous sinuses, and, most importantly, any focal lesion with its characteristic enhancement pattern.
3. Radiology Report Template for MRI Brain Pituitary (Dynamic Contrast-Enhanced)
This is a solid starting point for your personal macro. Drop the positive findings in, and you’re 90% of the way to a clean, attending-ready report.
Technique
Multiplanar, multisequence MRI of the pituitary was performed with and without intravenous contrast. This included pre-contrast sagittal and coronal T1-weighted images, coronal T2-weighted images, and dynamic post-contrast coronal T1-weighted images, followed by delayed post-contrast sagittal and coronal T1-weighted images. A total of [X] mL of [Gadolinium-based contrast agent] was administered intravenously.
Findings
Pituitary Gland: The pituitary gland measures approximately [X] mm in height (normal up to 8 mm in men and premenopausal women, 10 mm in pregnancy, 12 mm postpartum). The gland demonstrates [symmetric/asymmetric] morphology. The posterior pituitary bright spot is [present/absent].
Dynamic Contrast Enhancement: Following contrast administration, the normal pituitary gland enhances avidly and homogeneously. [There is a focal, rounded area of relatively delayed enhancement measuring [X] x [Y] mm in the [right/left/central] aspect of the adenohypophysis, consistent with a microadenoma. OR No focal pituitary lesion is identified on the dynamic or delayed sequences.]
Pituitary Stalk: The pituitary stalk is midline and measures [X] mm in thickness (normal <3.5-4 mm). It enhances normally.
Suprasellar Cistern and Optic Chiasm: The suprasellar cistern is clear. The optic chiasm is [normal in appearance/elevated/compressed] by [mass/gland].
Cavernous and Sphenoid Sinuses: The cavernous sinuses are symmetric and demonstrate normal enhancement. There is no evidence of cavernous sinus invasion. [If macroadenoma present, add Knosp grade: The mass demonstrates Knosp grade [0-4] cavernous sinus invasion on the [right/left].] The sphenoid sinus is clear.
Other: The remainder of the visualized brain parenchyma, ventricular system, and extra-axial spaces are unremarkable for the patient’s age.
Impression
1. [Size] mm hypoenhancing lesion in the [location] of the anterior pituitary, consistent with a pituitary microadenoma.
OR
1. No convincing evidence of a pituitary adenoma.
OR
1. [Size] cm pituitary macroadenoma with [suprasellar extension and compression of the optic chiasm / cavernous sinus invasion (Knosp grade X)].
2. Normal appearance of the pituitary stalk and posterior pituitary bright spot.
4. Free Template Sources for When You’re Building Your Library
Building a personal library of dictation macros is a rite of passage in residency. If you’re looking for more examples to build from, two great free repositories exist. The RSNA-curated RadReport.org has a broad collection of peer-reviewed templates. A solid alternative maintained by Australian radiologists is Radiology Templates, which also offers a wide range of templates for different modalities.
5. The Next-Level Move: Free-Form Dictation to Structured Report
The template above is great, but what if you could just dictate the positive findings and have the software handle the rest? That’s the core idea behind AI-powered reporting assistants. Instead of clicking through a structured template or editing a macro, you can simply dictate, “There’s a 5 mm hypoenhancing lesion in the left aspect of the anterior pituitary gland.” The AI then parses that, identifies the key finding, and slots it into the appropriate section of a pre-built, ACR-compliant template. It helps streamline the process, ensuring all the key elements—like measurements, location, and characterization—are captured without the manual busywork. These tools are designed to integrate Clinical Decision Support (CDS) for radiology reporting, flagging when a specific classification system like Knosp grading for cavernous sinus invasion should be applied based on your findings.
6. When Should You Order an MRI of the Brain and Pituitary? ACR Appropriateness Criteria
The American College of Radiology (ACR) provides evidence-based guidelines to help clinicians choose the right test for the right reason. For suspected pituitary pathology, the guidance is quite clear.
For patients with clinical and biochemical evidence of Cushing Syndrome (specifically, ACTH-dependent), an MRI of the sella with dynamic contrast is rated as “Usually Appropriate.” It’s the primary imaging modality for detecting the causative pituitary adenoma.
Similarly, in the workup of Hyperprolactinemia, an MRI of the sella is also “Usually Appropriate” to identify a prolactin-secreting adenoma (prolactinoma) or another sellar mass that could be causing the issue through stalk compression (the “stalk effect”).
When MRI is contraindicated (e.g., due to an incompatible implanted device), a CT of the sella with contrast can be performed, but it is significantly less sensitive for detecting microadenomas. If a high clinical suspicion for an ACTH-secreting microadenoma persists despite a negative MRI, the gold standard is bilateral inferior petrosal sinus sampling, an invasive procedure performed by interventional radiology.
7. How Much Radiation Does a Pituitary MRI Deliver?
This is an easy one. An MRI of the pituitary delivers an effective radiation dose of 0 mSv. Magnetic Resonance Imaging does not use ionizing radiation.
This is a key advantage, particularly in younger patients or those who may require serial imaging to monitor a known lesion. The ACR Relative Radiation Level designation for MRI is “O,” for none. There are no dose-reduction techniques to consider because there is no radiation dose to begin with.
8. MRI Brain Pituitary Imaging Protocol — Phases, Contrast, and Key Parameters
The diagnostic power of a pituitary MRI comes from a very specific, dedicated protocol. It’s not a generic brain sequence. The key is using thin slices with a small field of view focused on the sella, and most importantly, a rapid, multi-phase dynamic contrast-enhanced acquisition to differentiate the enhancement patterns of normal pituitary tissue versus an adenoma.
The principle is simple: the normal pituitary gland has a rich blood supply from the systemic circulation and enhances rapidly and intensely. Most adenomas, however, are supplied by the slower hypophyseal portal system. This differential enhancement timing means the adenoma will appear as a relatively dark (hypointense) spot against the brightly enhancing normal gland in the early dynamic phases.
| Sequence | Plane | Slice Thickness | Key Parameters |
|---|---|---|---|
| T1 SE | Sagittal | 3 mm | Pre-contrast, evaluates midline anatomy, posterior bright spot. |
| T1 SE | Coronal | 2-3 mm | Pre-contrast, high-resolution view of the gland. |
| T2 | Coronal | 2-3 mm | Evaluates for cystic components (e.g., Rathke’s cleft cyst). |
| Dynamic T1 | Coronal | 2-3 mm | CRITICAL SEQUENCE: 5-7 acquisitions every 15-20s post-contrast. |
| Post-Contrast T1 | Coronal | 2-3 mm | Delayed phase, evaluates macroadenomas, cavernous sinuses. |
| Post-Contrast T1 | Sagittal | 3 mm | Delayed phase, evaluates suprasellar extension. |
Common protocol pitfalls: The most common error is insufficient temporal resolution on the dynamic sequence. If the acquisitions are too slow, you can miss the window where the microadenoma is hypoenhancing relative to the normal gland. By the time you get to the delayed images (5-10 minutes), the adenoma may have “filled in” and become isointense, making it invisible.
9. The 3-Months-Free Offer for Radiology Residents and Fellows
Look like a rockstar on your reports — dictate positive findings in free form, and the AI generates a structured report using ACR + SIR templates with the appropriate clinical decision support firing automatically.
We’re offering 3+ months of free access to GigHz Precision AI for all radiology residents and fellows. All we ask in return is your feedback so we can keep improving the product for trainees. Signup is simple, with no credit card and no long forms. To get started, just provide these three items:
- Your PGY year (e.g., PGY-2, PGY-4)
- Your training type (radiology residency or specific fellowship)
- Your training program or hospital name
Ready to give it a try? You can apply for the residents free-access program here.
10. Frequently Asked Questions (FAQ)
Is GigHz Precision AI HIPAA-compliant?
Yes. The platform is designed for de-identified workflows by default. It operates on the anonymized text of your dictation and does not require access to Protected Health Information (PHI) or your hospital’s EMR or PACS to function.
Do I need my hospital’s IT department to set this up?
No. GigHz Precision AI is browser-based and requires no local software installation or special permissions. It works on any modern web browser, including the one on your call-room workstation or personal iPad.
How does this work with PowerScribe or other dictation systems?
It works alongside your existing dictation system, not as a replacement. Most residents dictate their positive findings into the GigHz web app, let the AI generate the structured report, and then copy/paste the final, clean text into their official reporting system for sign-off.
Can I use this on my phone or iPad?
Yes, the platform is fully responsive and works well on mobile devices and tablets, making it useful for reviewing cases or drafting reports away from a dedicated workstation.
Can I customize the report templates?
Yes, you can create and save your own custom templates and macros within the platform, tailoring the output to your specific preferences or your institution’s required format.
What happens after my residency or fellowship ends?
The free access is for trainees. After you graduate, you can transition to a standard attending plan. We offer discounts for recent graduates to help ease the transition into practice.
Free GigHz Tools That Pair With This Article
Three free tools that complement the material above:
- ACR Appropriateness Criteria Lookup — Type an indication or clinical scenario in plain language and get the imaging studies the ACR rates for it, with adult and pediatric radiation levels. Built directly from 297 ACR topics, 1,336 clinical variants, and 15,823 procedure ratings.
- GigHz Imaging Protocol Library — A searchable library of 131 imaging protocols with the physics specs surfaced and the matching ACR Appropriateness Criteria alongside. Plain-English narratives readable in 60 seconds, organized by modality.
- GigHz Radiation Dose Calculator — Pick the imaging studies a patient has had and see total dose in millisieverts (mSv) with comparisons to natural background radiation, transatlantic flights, and chest X-rays. Useful for shared decision-making.
Reviewed by Pouyan Golshani, MD, Interventional Radiologist — May 7, 2026
