Prepare a Patient for an Exam

General Instructions

Little preparation is needed for a CT scan. Patients, who do not have congestive heart failure or are not on dialysis, are asked to drink 64 ounces of water before the exam, especially if the exam is performed with oral or intravenous contrast. If possible, they should start drinking 12 hours before their scheduled appointment time.

If patient is receiving IV or contrast, they should not eat or drink 4 hours prior to exam.

Patients will be asked to remove jewelry and other metallic objects that might interfere with the scan. We ask patients to leave jewelry at home when possible. 

Patients who are breastfeeding should be given an opportunity to make an informed decision about whether to continue breastfeeding after receiving intravascularly administered iodinated contrast media or to temporarily abstain. A very small percentage of iodinated contrast medium can be excreted into the breast milk and absorbed by the infant’s gut. We believe that the available data suggests that is safe for the mother and infant to continue breastfeeding after receiving such an agent.

The patient can choose to temporarily abstain from breastfeeding for 24 hours with the active expression and discarding of breast milk from both breast during that period. If so, the patient may wish to use a breast pump to obtain milk beforehand to use during the 24 hour period following the administration of contrast media. Please inform the patient of this option when the exam is scheduled. 

Patient Screening Prior to Administration of Iodinated Contrast

Prior to the administration of iodinated contrast, patients are screened for the following:

  • Previous reactions to iodinated contrast media
  • All severe allergies and reactions (both medications and food)
  • History of diabetes, kidney disease, pheochromocytoma, solitary kidney, kidney or other transplant, or myeloma
  • Current use of any metformin-containing medications
  • Pregnant or breast-feeding (in women of child-bearing age).

Premedication Instructions for Patients with Contrast Allergies

Prednisone 50mg po at 13 hours, 7 hours and 1 hour prior to planned administration of intravenous contrast plus diphenhydramine 50mg po, iv or im at 1 hour prior to planned administration of intravenous contrast


Methylprednisolone 32mg po at 12 hours and 2 hours prior to planned administration of contrast plus diphenhydramine 50 mg po, iv or im at 1 hour prior to the planned administration of contrast


Hydrocortisone 200mg iv at 13 hours, 7 hours and 1 hour prior to planned administration of intravenous contrast if patient is unable to take po medications

Creatinine Testing Prior to Contrast Administration

Routine creatinine testing prior to contrast administration is not necessary in all patients. The test should be obtained within 30 days of contrast administration for patients with renal disease, HIV+, diabetic, hypertensive, over 60 years or on chemotherapy. 

Contrast Administration in Patients with Elevated Creatinine

Estimated glomerular filtration rate is a better predicator of renal dysfunction than creatinine alone. The decision to proceed with contrast administration in patients with an estimated GFR < 45 ml/min/1.732 is a matter of clinical judgment, based on the individual circumstances of the patient and following consultation between the radiologist and requesting physician. Strategies to prevent nephropathy in patients with renal impairment include hydration, reduction of contrast dose, and discontinuation of nephrotoxic drugs. A critical diagnostic study should not be delayed because of excessive concern regarding possible contrast nephropathy.        

Contrast Administration in Patients with Renal Failure

Patients on dialysis can receive IV contrast, and early post-procedural dialysis is not routinely required. However, the fact that a patient is on dialysis should not be regarded as automatically allowing the administration IV contrast. The administration of contrast may jeopardize the return of renal function in patients who are receiving dialysis for acute renal failure and may further worsen renal function in patients who still make some urine but receive dialysis intermittently. The volume of IV contrast should also be considered in patients on dialysis who are at risk for volume overload.

Contrast Administration in Patients Receiving Metformin

Metformin should be discontinued at the time of the procedure, withheld for 48 hours subsequent to the procedure, and reinstituted only after renal function has been re-evaluated and found to be normal.

Contrast Administration in Pregnant Patients

The iodine content of contrast media has the potential to cause hypothyroidism in the neonate. Pregnant women who receive an intravenous iodinated contrast agent are counseled that neonatal thyroid function should be checked in the first week of life. Informed consent is obtained prior to the administration of contrast in pregnant patients.

You may provide your patients with the following education documents: 

Cardiac Calcium Scoring Only Scan
Computed Tomography (CT)
Computed Tomography Angiography
Computed Tomography (CT) Cardiac

They may also visit 

General Instructions

All unnecessary metallic objects, including jewelry and drug delivery patches, must be removed prior to the exam.

All patients and other individuals in the room during the actual scan receive acoustic noise protection. When possible, two forms of noise protection are utilized, i.e. ear plugs and pads or head phones.

Patient Screening Prior to MRI

Patients are thoroughly screened for any absolute contraindications to an MRI which are: 

  • Intracranial aneurysm clips
    • If installed at Vanderbilt University Medical Center (VUMC) after January 1, 2000, it can be scanned at 1.5T. If it was not installed at VUMC, documentation of the implant (including manufacture, make and model number) and date of installation is required. Determination to scan with the implant will depend on the required documentation.

  • Ocular metallic foreign bodies
    • If the patient or guardian is not sure of the presence of an ocular object, but there is a significant likelihood based upon the individual's past experience or occupation, MRI is not performed until independent verification is made.
    • To independently verify the presence or absence of an ocular object, the patient should be referred for an x-ray procedure. A single Water's view is normally sufficient; however, a supplementary CT exam of the orbits using 3mm contiguous slices may also be required at the discretion of the attending radiologist following review of the plain film.
  • Cardiac pacemakers
    • There are Pacemakers/ICD/CRTD that are MRI conditional. Documentation of implant (including manufacture, make and model number) and date of installation is required. If it was not installed or followed-up at VUMC, a Chest X-ray is required. Determination to scan with the implant will depend on the required documentation.

  • Any electrically active implant

Patients are also screened for other potential contraindications to an MRI which include:

  • Cochlear implants
    • There are Cochlear implants that are MRI conditional. Documentation of implant (including manufacture, make and model number) and date of installation is required. Determination to scan with the implant will depend on the required documentation.

  • Any known ferromagnetic metallic materials within the body
  • Pregnancy
  • Coils, stents, and filters 
    • Patients with a history of coil, filter or stent implantation are not granted access to the MRI scan room until the device is identified and the manufacture’s MRI labeling information is reviewed and approved. 
    • Patient is scanned according to the manufacturer guidelines in regards to surface coil selection, dB/dt, T/m, G/cm monitoring of Specific Absorption Rate (SAR) and magnet strength, and configuration.

Creatinine Testing Prior to Gadolinium Administration

Routine creatinine testing prior to contrast administration is not necessary in all patients.  Serum creatinine with calculation of eGFR should be performed in patients with any of the following risk factors:

  • Age over 60
  • History of kidney disease, including tumor and transplant
  • Family history or kidney failure or disease
  • Diabetes treated with insulin or other prescribed medications
  • Hypertension requiring medication
  • Multiple myeloma
  • Solid organ transplant
  • History of severe liver disease

Gadolinium in Patients with Impaired Renal Function

Nephrogenic systemic fibrosis (NSF), a serious, debilitating, and sometimes fatal scleroderma-like disorder, is associated with the administration of intravenous gadolinium. The primary risk factor is renal failure (patient on dialysis or with a GFR < 30). 

MRI in Pregnant Patients

MRI procedures in pregnant patients are performed only in those cases where the only alternative procedures utilize ionizing radiation and the procedure cannot be reasonably postponed until after the pregnancy. If it is decided that the procedure is to be performed, the radiologist must explain the benefits/risk of the procedure to the patient and obtain written consent.

Gadolinium in Pregnant Patients

Intravenous gadolinium is contraindicated in pregnancy. It should only be used if absolutely essential and only after discussion of the potential risks and benefits with the patient and referring clinician. 

You may provide your patients with the following education documents: 

Magnetic Resonance Angiography (MRA)
Magnetic Resonance Cholangiopancreatography (MRCP)
Magnetic Resonance Enterography (MRE)
Magnetic Resonance Imaging (MRI)

They may also visit 

General Instructions

The patient should arrive 30 minutes before appointment time to check in and complete paperwork. Copies of outside scans, if available, should be brought to the department.

If the patient doesn't follow preparation instructions carefully, the test may not be accurate, and they may need to repeat the scan. It is also likely the scan would need to be rescheduled. 

The patient should be NPO (except water) for 6 hours prior to their appointment time. They should not chew gum or use mints at least 6 hours before the scan. Patients should not do any intense physical activities 24 hours before the scan. This includes physical therapy.

Smoking and nicotine should be avoided immediately prior to the scan.

All jewelry and metal should be removed prior to entering the scan room.

For the procedure, the patient will be escorted to a prep room where they will be injected with FDG for the scan. There are no side effects from the injection of radiolabeled glucose. They will rest quietly in the prep room for approximately 1 hour depending on the type of scan being performed. Subsequently, they will be brought into the scan room to have their scan performed. Most scans take 1.5 to 2 hours. They should plan for their entire visit to be at least 2.5 hours. In some cases, it may take longer.

Patients with Diabetes

Patients with type 1 diabetes need to be euglycemic without recent injection of insulin. The study should be scheduled for late morning, with the patient eating a normal breakfast at around 7am and taking the normal amount of insulin. The patient should then fast for at least 4 hours before the exam.

Patients with type 2 diabetes should fast for at least 4 hours and continue oral hypoglycemic as usual.

For Patients who are Claustrophobic

If claustrophobic, the patient should bring a driver with them to the appointment. They should inform the technologist upon arrival in the department that they are claustrophobic. They may be offered Valium, if they have a driver and it is not contraindicated. Alternatively, they can be prescribed an anti-anxiety medication to take immediately prior to arrival in the department.

For Patients with Thyroid Cancer

For patients with thyroid cancer, who have rising thyroglobulin and negative I 131 scan, FDG PET can be used to evaluate for papillary and follicular thyroid cancer. These patients should be pretreated with thyrogen prior to their PET scan. This can be scheduled in the nuclear medicine department or through their the referring provider's office.

You may provide your patients with the following education documents: 

PET Scan

They may also visit 

Each patient will receive a call from a nurse at least five days prior to the appointment unless the appointment is made less than five days prior to the scheduled date and time. During this call, the nurse reviews the patient’s medical history and medication list and gives the patient instructions based on the type of procedure that is scheduled. 

General Instructions

Patients who are undergoing outpatient procedures should arrive 1 hour before their scheduled appointment time and check-in at the radiology front desk (room 1145) in the main Vanderbilt University Hospital. 

Patients who are undergoing a procedure that requires overnight observation should arrive 1.5 hours before their scheduled appointment time and should stop by the admitting office prior to checking in at the radiology front desk.

Patients should leave all valuables at home.

Patients who will receive sedation or anesthesia during their procedure must have a friend or family member available to drive them home and care for them for the next 24 hours. 

Most procedures that involve sedation last 1 to 2 hours with a 2 to 4 hour recovery period following the procedure. The patient should expect to be here for at least 4 to 6 hours. 

NPO (Fasting) and Medication Instructions

Only patients who will receive sedation or anesthesia during the procedure need to be NPO.

  • No solid food or milk products for 6 hours prior to the procedure.
  • No clear liquids for 2 hours prior to the procedure.
  • Take all regular medications as scheduled with small sips of water unless otherwise directed.
  • For medicine for diabetes: take only half dose of evening insulin; hold morning insulin and oral diabetic medication the day of the procedure. 
  • There are many anticoagulants, aspirins and non-steroidal anti-inflammatory medications that may need to be held prior to your procedure. Patients should be asked to keep medical team informed of all medications the patient is taking. If needed, prior to a procedure, our team can review specific medications and plan to manage manage anticoagulation. 

Instructions for Holding Medications Prior to Procedures

  Medication Instruction
  ASA 325mg Hold 5 days
  ASA 81mg Do not hold
  Plavix Hold 5 days
  Coumadin Hold for INR </= 1.5
  Lovenox therapeutic dose (1mg/kg) Hold 24 hours
  Lovenox prophylactic dose (30 – 40 mg) Hold 12 hours
  Fundaperinux (Arixtra) Hold 24 hours
  SQ Heparin Hold AM dose
  Aggrenox Hold 7 days
  Dabigatron (Pradaxa)

Hold for: 2 days if CrCl>50, 3 – 5 days if CrCl<50

  Fragmin Hold dose the day of procedure
  NSAIDs Hold 48 hours before liver, lung or kidney biopsies
  Insulin – if pt NPO Hold all po and long-acting insulin  Take ½ short-acting insulin dose the morning of the procedure
  Metformin  Hold for 48 hours after procedure and confirm normal renal function prior to restarting


Informed Consent

The Department of Radiology recognizes the right of all patients to make informed decisions regarding health care. Informed consent is obtained prior to all interventional or invasive procedures in accordance with the policy approved by Vanderbilt University Medical Center.

You may provide your patients with the following education documents: 

Bland Embolization
CT-Guided Lung Biopsy
Image-Guided Biopsy
Inpatient Paracentesis
Liver Biopsy
Mapping Arteriogram
Outpatient Paracentesis
Outpatient Thoracentesis
Percutaneous Cryoablation
Portal Vein Embolization
Y-90: After Your Test
Y-90: General Information

They may also visit 

General Instructions

Most ultrasound examinations do not require any preparation. Patients undergoing an abdominal, gallbladder or renal artery ultrasound should fast for at least 6 hours prior to the exam. Patients undergoing OB Prenatal or Transvaginal Pelvic ultrasound may be asked to drink several glasses of clear fluids prior to the exam in order to have a full bladder. 

You may provide your patients with the following education documents: 

Abdominal Ultrasound
Doppler Duplex Ultrasound
OB Prenatal Ultrasound
Transvaginal Pelvic Ultrasound

They may also visit 

General Instructions

No preparation is needed for a routine X-ray. 

Most GI studies such as esophagrams, UGI's, and barium enemas require that patients fast for 8 hours prior to the exam. Exams such as feeding tube checks to verify placement, nephrostograms, and cystograms do not require patients to be fasting. Enemas and IVP patients are required to do a colon cleansing prep prior to the exam.

You may provide your patients with the following education documents: 

Barium enema
Esophagram-barium swallow
Intravenous pyelogram (IVP)
Lumbar puncture (spinal tap)
Modified barium swallow
Small bowel follow-through series
Sniff test
Upper GI series
Voiding cystogram

They may also visit