MRI Pelvis — general gynaecological

Pelvic brim to below the perineum, with the kidneys included where a congenital anomaly or ureteric obstruction is possible.

Typical, not policy

Timings, volumes and delays here are representative values drawn from published guidance. Scanner generation, injector, cardiac output and local preference all move them. Confirm against your department's own protocol before you rely on a number.

Premedication

Given to make the acquisition work, not to treat the patient. Doses are typical — confirm against your local protocol and prescribe within your own governance.

Hyoscine butylbromide (Buscopan), or glucagon where unavailable — where locally used

Suppression of small bowel and rectal peristalsis over the pelvis, so that the long high-resolution T2 and diffusion acquisitions are not degraded by ghosting from overlying bowel. This protocol already names its absence as a pitfall; the dose is the part that pitfall does not supply.

Dose and route: Typically 20 mg intravenously, or about 20 mg intramuscularly where the study is unenhanced and no cannula is otherwise needed. Glucagon roughly 0.25-1 mg intravenously where hyoscine is contraindicated or unavailable.
When: Immediately before the high-resolution T2 and diffusion series. The effect lasts only a few minutes against an examination of 20-30 minutes, so it should be timed to the sequences that matter rather than given on arrival.
Do not give if: If glucagon is used instead of hyoscine, it carries its OWN absolute contraindications rather than inheriting a clean slate: phaeochromocytoma, where it provokes catecholamine release and hypertensive crisis, and insulinoma or glucagonoma, where it causes rebound hypoglycaemia. It also raises blood glucose transiently, which matters in diabetes, and commonly causes nausea and vomiting.
MHRA Drug Safety Update (February 2017), issued after nine reported deaths mostly from cardiac arrest: in patients with cardiac disease, monitor the patient and ensure resuscitation equipment AND staff trained to use it are readily available before giving it. This is an availability requirement, not a caution to note and move past.
Not universal. ESUR technique guidance supports a spasmolytic for female pelvic MRI where available and not contraindicated, but departments differ, and for a straightforward fibroid or dermoid question many omit it — confirm the local protocol.
Contraindicated in untreated angle-closure glaucoma, myasthenia gravis, megacolon, and significant tachyarrhythmia.
Caution in prostatic enlargement with urinary retention, and in significant cardiac disease.
Warn the patient about transient blurred vision, and that they must not drive until it resolves.
If unsuitable: Proceed without it. Fasting for a few hours beforehand reduces bowel activity, and repeating a degraded sequence is usually sufficient for a routine gynaecological question.

When to use it

Characterisation of an adnexal mass that ultrasound has left indeterminate.
Mapping fibroids before myomectomy, embolisation or ablation.
Suspected adenomyosis.
Suspected congenital uterine anomaly, where the external fundal contour is the discriminator.
Assessment of a pelvic mass of uncertain origin.

Technique

Sagittal T2 and axial T2 of the pelvis, with an oblique plane aligned to the uterine long axis where uterine pathology is the question.
Axial T1 in and out of phase, or T1 with and without fat suppression, to identify fat and blood products — the pair that distinguishes a dermoid from an endometrioma.
Diffusion-weighted imaging for solid components.
Post-contrast fat-suppressed T1 where solid enhancing components in an adnexal mass or the extent of a pelvic mass must be established.

Where it goes wrong

Omitting the fat-saturated T1, without which a fat-containing lesion cannot be confidently distinguished from a haemorrhagic one.
No antiperistaltic agent, leaving bowel motion across the high-resolution sequences.
Bladder too full, causing motion and patient distress during long acquisitions; too empty, losing anatomical separation.
Failure to include the kidneys when a Müllerian anomaly is suspected, missing the associated renal agenesis.
Giving gadolinium for a question that unenhanced sequences already answer.

Clinical questions that reach this study

Suspected ectopic pregnancy Acute pelvic pain in the reproductive age group (including suspected PID and tubo-ovarian abscess)Suspected ovarian (adnexal) torsion Adnexal mass — characterisation and risk stratification Suspected endometriosis, including deep disease Abnormal uterine bleeding and endometrial assessment Suspected ovarian cancer or indeterminate adnexal mass Endometrial cancer — staging Cervical cancer — staging

Contrast

NoneGadolinium, intravenous

Where contrast is used, a macrocyclic gadolinium agent at a typical single dose of about 0.1 mmol/kg with fat-suppressed T1 afterwards.

Many gynaecological questions — fibroid mapping, congenital anomaly, simple adnexal characterisation — are answered on unenhanced T1 and T2 alone.

Acquisition

Breathing: Free breathing with an antiperistaltic agent; the high-resolution T2 sequences are the ones bowel motion ruins.
Preparation: Moderate bladder filling is wanted for most gynaecological protocols; an over-full bladder causes motion and an empty one loses anatomical separation. Fasting for a few hours plus an antiperistaltic agent reduces bowel motion for high-resolution sequences. Intrauterine devices are MR-conditional in general but must still be declared at screening.

Safety checks this protocol carries

Derived from the contrast agent and phases above, not authored here — which is why they cannot drift apart from what the protocol actually does.

Kidney function and gadolinium-based contrast· radiographer at scan
MR safety screening for implants and foreign bodies· radiographer at scan
Gadolinium in known or possible pregnancy· radiographer at scan