How to Prepare for an Ultrasound Scan:
A Complete Guide
Preparation varies by scan type. Getting it right ensures the best possible image quality and avoids the need to reschedule.
In brief: Preparation requirements vary significantly by scan type. Abdominal ultrasound requires 4–6 hours of fasting; transabdominal pelvic ultrasound requires a full bladder; most other scans require no preparation at all. The table below summarises everything you need to know for your specific scan at Victoria Medical.
Preparation by Scan Type
| Scan Type | Fasting / Food | Bladder |
|---|---|---|
| Abdominal ultrasound | Fast for 4–6 hours (no food or non-water drinks). Water is fine. | Empty or comfortably full if bladder assessment needed |
| Pelvic ultrasound (transabdominal) | No fasting required. | Full bladder — drink 1 litre of water 1 hour before |
| Pelvic ultrasound (transvaginal) | No fasting required. | Empty bladder preferred |
| MSK ultrasound | No preparation needed. | Not relevant |
| Vascular Doppler (DVT) | No preparation needed. | Not relevant |
| Thyroid ultrasound | No preparation needed. | Not relevant |
| Breast ultrasound | No preparation needed. | Not relevant |
| Echocardiogram | No preparation needed. Avoid heavy meals immediately before. | Not relevant |
Why Preparation Matters
Adequate preparation directly affects image quality. For abdominal ultrasound, fasting allows the gallbladder to fill with bile — making it much easier to visualise and assess for gallstones. A 2023 study confirmed that point-of-care ultrasound has a sensitivity of 94% for acute cholecystitis when performed under optimal conditions.[1] For pelvic ultrasound, a full bladder displaces bowel loops and provides an acoustic window that significantly improves visualisation of the uterus and ovaries.[2]
Arrive 5–10 minutes early for registration
Bring any previous scan reports or results
Wear comfortable, loose-fitting clothing
Continue all regular medications
Inform us if you are pregnant or may be pregnant
Let us know if you have any allergies or sensitivities
Frequently Asked Questions
What happens if I eat before an abdominal ultrasound?
Eating before an abdominal ultrasound causes the gallbladder to contract (releasing bile), making it much harder to visualise. Bowel gas from digestion also obscures the view of other organs. If you have eaten within 4 hours of your appointment, please inform our team — we may need to reschedule the scan for optimal image quality.
How full should my bladder be for a pelvic ultrasound?
For a transabdominal pelvic ultrasound, a comfortably full bladder acts as an acoustic window, improving visualisation of the uterus and ovaries. Drink approximately 1 litre of water in the hour before your appointment and do not empty your bladder. For a transvaginal scan, an empty bladder is preferred.
Can I take my medications before an ultrasound?
Yes. Continue all prescribed medications as normal. Take them with a small amount of water. If you are diabetic and fasting for an abdominal scan, discuss your medication timing with your GP before the appointment.
What should I wear to my ultrasound?
Wear loose, comfortable clothing that allows easy access to the area being scanned. For abdominal or pelvic scans, a two-piece outfit is ideal. For MSK scans of the shoulder or elbow, a sleeveless top is helpful. For knee or ankle scans, shorts or trousers that can be rolled up are ideal.
Can I bring someone with me to my ultrasound?
Yes. You are welcome to bring a partner, friend, or family member to your appointment. Please let us know when booking if you would like a chaperone present during the scan.
References
- [1]Dumbrava B, Puia A, Dumbrava M, et al. The Accuracy of Point-of-Care Ultrasound (POCUS) in Acute Gallbladder Disease. Diagnostics. 2023;13(3):412. https://doi.org/10.3390/diagnostics13030412
- [2]Guerriero S, Condous G, van den Bosch T, et al. Systematic approach to sonographic evaluation of the pelvis in women with suspected endometriosis. Ultrasound Obstet Gynecol. 2016;48(3):318–332. https://doi.org/10.1002/uog.15955
- [3]NICE. Gallstone disease: diagnosis and initial management. NICE guideline NG188. 2014 (updated 2023). https://www.nice.org.uk/guidance/ng188
- [4]Bhatt M, Bhatt DL, et al. Diagnosis of deep vein thrombosis: a systematic review and meta-analysis. Blood Adv. 2020;4(7):1250–1264. https://doi.org/10.1182/bloodadvances.2019001250
- [5]Farooqi AS, Bhatt DL, et al. Diagnostic Accuracy of Ultrasonography for Rotator Cuff Tears. Orthop J Sports Med. 2021;9(5). https://doi.org/10.1177/23259671211002298
- [6]Tessler FN, Middleton WD, Grant EG, et al. ACR Thyroid Imaging, Reporting and Data System (TI-RADS). J Am Coll Radiol. 2017;14(5):587–595. https://doi.org/10.1016/j.jacr.2017.01.046
Dr George Xynopoulos
Consultant Physician & Cardiologist | GMC Registered | MRCP (UK)
Dr Xynopoulos is a Consultant Physician and Cardiologist at Victoria Medical, 170 Vauxhall Bridge Road, London.
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