This 51-year-old woman was found in her automobile in an apparent post-ictal state. No focal deficits were noted, but the patient had signs of frontal lobe release. She had a long history of lupus and the diagnosis of lupus vasculitis was entertained. Cytoxan therapy was contemplated. The patient had severe renal disease.
Prepared by John F. Healy, MD of the Veterans
Administration Medical Center in San Diego, CA.
This 51-year-old woman was found in her automobile in an
apparent post-ictal state. No focal deficits were noted, but the
patient had signs of frontal lobe release. She had a long history
of lupus and the diagnosis of lupus vasculitis was entertained.
Cytoxan therapy was contemplated. The patient had severe renal
Low contrast dose digital selective angiography with careful
renal mon-itoring was advised. However, the clinicians opted for
magnetic res-onance angiography (MRA) at another institution. At
that institution, a diagnosis of proximal left middle cerebral
arteritis was made solely on the basis of the maximum intensity
projected algorithm images (figure 1). The sagittal localizer and
the MRA source images were not viewed by the radiologist. Most
experts recommend that MRA never be performed without an
accompanying MRI and that source images always be examined. These
dictums were not followed in this case.
When the patient returned to our hospital, we did not feel that
the above study was adequate. An MRI was performed and an MRA was
repeated with filming and complete evaluation of the source
The sagittal localizer, done but not viewed at the outside MRI
facility, clearly showed an isodense mass with edema in the left
frontal lobe (figure 2). The edema and mass effect were also noted
on the MRA source images (figure 3). No evidence of vasculitis was
noted (figure 4). Contrast-enhanced MRI scan revealed a left
frontal meningioma (figure 5).
When the MRA examination was done properly (with viewing of
source images and localizer images and accompanied by an MRI
examination), this patient was spared unnecessary treatment
(cytoxan therapy) for a disease that she did not have (lupus
vasculitis). In addition, the poorly performed incomplete
examination did not diagnose her real disease (meningioma),
although adequate MRI data (source images and sagittal localizer)
had been acquired from and billed to the patient.
Magnetic resonance angiography has proven to be a helpful
screening test in neuroradiology. Generally, a normal MRA study
precludes significant disease in the carotid arteries. Subtle
intracranial disease may be missed by MRA; however, clinical
practice has borne out the expectation that false positives are a
more significant problem with MRA than false negatives.
Cost cutting efforts and managed care often encourage incomplete
and thus less costly imaging evaluation of sick patients. When an
MRA is done improperly and incompletely, the chances for error are
Intracerebral magnetic resonance angiography examinations should
be performed in conjunction with an MR examination of the brain.
Source images should always be examined. It is poor practice to
rely solely on maximum intensity projected images. This case
dramatically emphasizes the need to adhere to these basic tenets of
MRA; when they were violated, a misdiagnosis was made. This was
rectified by a properly performed examination a few days later.
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