Imaging Newsletter, August 2007


Inpatient Imaging Utilization Guidelines

Lumbar Spine MR and CT

MR and/or CT is generally not indicated for the lumbar spine until there have been six weeks of unsuccessful conservative therapy unless there is a "red flag" suggesting a medically emergent condition. Red flags include:

  • Paralysis or other significant acute neurological deficit (sensory deficits are not generally sufficient)
  • Bladder or bowel incontinence
  • Acute fracture/dislocation secondary to trauma if plain films are not conclusive
  • Metastatic disease
  • Cauda equina compression signs
  • Suspected epidural abscess (neurological deficit, pain and signs of infection)
  • Spinal cord injury (myelopathy)

The following red flags justify MR or CT imaging, but not on an emergent basis:

  • Recurrent symptoms after surgery
  • Planning for procedures such as epidural steroids or surgery
  • Suspected spinal cord tumor

MR or CT imaging is not indicated for chronic degenerative disease unless surgery or other interventional procedures are anticipated.

Imaging should only be performed if findings will potentially affect treatment.

Spinal Trauma - MR Imaging

MR imaging is indicated for spinal trauma when:

  • A fracture is suspected and CT is not diagnostic
  • An unstable fracture is diagnosed by CT and there are associated neurological deficit or symptoms
  • Neurological deficits temporally related to the trauma

Chest X-rays

Chest X-rays should not be ordered on a daily basis in advance, but only as indicated. All patients in the ICU's do not require daily chest X-rays, but only as indicated by clinical signs or symptoms.

Head Trauma

CT of the head is indicated in patients with head trauma complicated by:

  • Loss of consciousness for more than a few minutes
  • Neurological signs
  • Loss of hearing or smell/taste
  • Subsequent alterations of alertness
  • Evidence of penetrating trauma or high clinical suspicion of fracture

Post traumatic headache is not an indication for acute head CT until a week or two of symptoms persist. At that time, MRI is probably the better examination.

Headache

Indications for emergency CT for patients with headache should include:

  • An acute onset of a severe headache (thunderclap headache, especially if associated with a stiff neck). Such headaches do not build; they are severe from the outset. These are often described as the "worst headache of my life." Such headaches that have lasted more than 48 hours are usually better evaluated by MR, or by CTA or MRA if an aneurysm is suspected.

CT for Chronic Headache

Chronic migraine, tension headache and cluster headache do not generally require advanced imaging if the course has been stable. Severe worsening of an established chronic headache disorder (change in pattern, marked change in frequency or significant worsening of severity) or the appearance of any red flags may warrant imaging. The same is true for the new onset of headaches that are not of the severe immediate type described above, unless associated with red flags. Red flags include:

  • Marked worsening with a valsalva maneuver
  • Focal neurological signs or papilledema
  • Decreased coordination or mental status changes not due to medications
  • Headache frequently awakens the patient at night
  • The patient is over 50 when the headaches began
  • The headache is felt to be atypical of any know benign pattern

Cervicogenic headache is not an established diagnosis. Abnormalities that can be identified with advanced imaging are not known to be associated with it and cervical MRI and CT are generally not indicated.

Emergency CT is not indicated for headaches associated with intracranial hypotension which are usually associated with significant increase with upright posture and relief by lying flat.

CTA/MRA of the Neck

For atherosclerotic disease, doppler ultrasound of the neck is usually sufficient to determine degree of stenosis. CTA or MRA should be reserved for cases in which the doppler is not diagnostic.

If additional imaging to a doppler study is required, CTA or MRA, but not both, are appropriate, absent any overriding clinical justification for both.

Abdominal CT/Ultrasound in the Emergency Setting

Ultrasound and CT are excellent techniques for evaluating patients with acute abdominal pain. They should be ordered independently of each other and only as appropriate.

For women with pelvic or right lower quadrant pain, the ordering physician should determine the most likely etiology, and then order the appropriate study. For instance, if appendicitis is suspected, CT is the appropriate study. However, if ovarian pathology is considered more likely, ultrasound will usually suffice. Both studies should not be ordered simultaneously but rather the second study should only be ordered when the information from the first examination is not adequate.

MRA/CTA of the Chest

Only in rare cases should MRA and CTA of the chest be ordered. The specific rational should be explained at the time of the request. In general, follow-up MRA exams should be performed only when there is a clinical change, with new signs or symptoms, or specific findings requiring imaging surveillance.

Request for re-imaging due to technically limited exams is the responsibility of the imaging providers.

Common indications for chest MRA include:

  • Aneurysm
  • Atheromatous disease, including penetrating atherosclerotic aortic ulcer
  • Congenital anomalies
  • Dissection
  • Intramural hematoma
  • Postoperative evaluation for:
    • Infection
    • Leak
    • Pseudo-aneurysm
  • Stent graft evaluation
  • Subclavian steal
  • Systematic venous thrombosis reclusion, including SVC syndrome
  • Thoracic outlet syndrome
  • Vascular involvement from neoplasm
  • Vasculitis

Sinus CT

Acute sinusitis - CT is not usually performed at the initial presentation and should be reserved for cases which have not responded to medical therapy of three to four weeks. Acute sinusitis is considered a self limiting disease since most patients improve within 2 weeks, and imaging is generally not required in the absence of complications. Limited coronal sinus CT is usually reserved for recurrent or refractory sinus inflammatory disease, or if the diagnosis is in doubt. Full sinus CT is generally performed for surgical planning to check for osteomeatal obstruction, fungal sinusitis, facial orbital cellulitis complicating sinusitis or suspected malignancy.


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Inpatient Imaging Guidelines


Lumbar Spine MR and CT

MR and/or CT is generally not indicated for the lumbar spine until there have been six weeks of unsuccessful conservative therapy unless there is a "red flag" suggesting a medically emergent condition. Red flags include:

  • Paralysis or other significant acute neurological deficit (sensory deficits are not generally sufficient)
  • Bladder or bowel incontinence
  • Acute fracture/dislocation secondary to trauma if plain films are not conclusive
  • Metastatic disease
  • Cauda equina compression signs
  • Suspected epidural abscess (neurological deficit, pain and signs of infection)
  • Spinal cord injury (myelopathy)

The following red flags justify MR or CT imaging, but not on an emergent basis:

  • Recurrent symptoms after surgery
  • Planning for procedures such as epidural steroids or surgery
  • Suspected spinal cord tumor


MR or CT imaging is not indicated for chronic degenerative disease unless surgery or other interventional procedures are anticipated.

Imaging should only be performed if findings will potentially affect treatment.

Spinal Trauma - MR Imaging

MR imaging is indicated for spinal trauma when:

  • A fracture is suspected and CT is not diagnostic
  • An unstable fracture is diagnosed by CT and there are associated neurological deficit or symptoms
  • Neurological deficits temporally related to the trauma


Chest X-rays

Chest X-rays should not be ordered on a daily basis in advance, but only as indicated. All patients in the ICU's do not require daily chest X-rays, but only as indicated by clinical signs or symptoms.

Head Trauma

CT of the head is indicated in patients with head trauma complicated by:

  • Loss of consciousness for more than a few minutes
  • Neurological signs
  • Loss of hearing or smell/taste
  • Subsequent alterations of alertness
  • Evidence of penetrating trauma or high clinical suspicion of fracture


Post traumatic headache is not an indication for acute head CT until a week or two of symptoms persist. At that time, MRI is probably the better examination.

Headache

Indications for emergency CT for patients with headache should include:

  • An acute onset of a severe headache (thunderclap headache, especially if associated with a stiff neck). Such headaches do not build; they are severe from the outset. These are often described as the "worst headache of my life." Such headaches that have lasted more than 48 hours are usually better evaluated by MR, or by CTA or MRA if an aneurysm is suspected.

CT for Chronic Headache

Chronic migraine, tension headache and cluster headache do not generally require advanced imaging if the course has been stable. Severe worsening of an established chronic headache disorder (change in pattern, marked change in frequency or significant worsening of severity) or the appearance of any red flags may warrant imaging. The same is true for the new onset of headaches that are not of the severe immediate type described above, unless associated with red flags. Red flags include:

  • Marked worsening with a valsalva maneuver
  • Focal neurological signs or papilledema
  • Decreased coordination or mental status changes not due to medications
  • Headache frequently awakens the patient at night
  • The patient is over 50 when the headaches began
  • The headache is felt to be atypical of any know benign pattern

Cervicogenic headache is not an established diagnosis. Abnormalities that can be identified with advanced imaging are not known to be associated with it and cervical MRI and CT are generally not indicated.

Emergency CT is not indicated for headaches associated with intracranial hypotension which are usually associated with significant increase with upright posture and relief by lying flat.

CTA/MRA of the Neck

For atherosclerotic disease, doppler ultrasound of the neck is usually sufficient to determine degree of stenosis. CTA or MRA should be reserved for cases in which the doppler is not diagnostic.

If additional imaging to a doppler study is required, CTA or MRA, but not both, are appropriate, absent any overriding clinical justification for both.

Abdominal CT/Ultrasound in the Emergency Setting

Ultrasound and CT are excellent techniques for evaluating patients with acute abdominal pain.

They should be ordered independently of each other and only as appropriate.
For women with pelvic or right lower quadrant pain, the ordering physician should determine the most likely etiology, and then order the appropriate study. For instance, if appendicitis is suspected, CT is the appropriate study. However, if ovarian pathology is considered more likely, ultrasound will usually suffice. Both studies should not be ordered simultaneously but rather the second study should only be ordered when the information from the first examination is not adequate.

MRA/CTA of the Chest

Only in rare cases should MRA and CTA of the chest be ordered. The specific rational should be explained at the time of the request. In general, follow-up MRA exams should be performed only when there is a clinical change, with new signs or symptoms, or specific findings requiring imaging surveillance.

Request for re-imaging due to technically limited exams is the responsibility of the imaging providers.

Common indications for chest MRA include:

  • Aneurysm
  • Atheromatous disease, including penetrating atherosclerotic aortic ulcer
  • Congenital anomalies
  • Dissection
  • Intramural hematoma
  • Postoperative evaluation for:
    • Infection
    • Leak
    • Pseudo-aneurysm
  • Stent graft evaluation
  • Subclavian steal
  • Systematic venous thrombosis reclusion, including SVC syndrome
  • Thoracic outlet syndrome
  • Vascular involvement from neoplasm
  • Vasculitis

Sinus CT

Acute sinusitis - CT is not usually performed at the initial presentation and should be reserved for cases which have not responded to medical therapy of three to four weeks. Acute sinusitis is considered a self limiting disease since most patients improve within 2 weeks, and imaging is generally not required in the absence of complications. Limited coronal sinus CT is usually reserved for recurrent or refractory sinus inflammatory disease, or if the diagnosis is in doubt. Full sinus CT is generally performed for surgical planning to check for osteomeatal obstruction, fungal sinusitis, facial orbital cellulitis complicating sinusitis or suspected malignancy.