Case 20 - Mycotic Aneurysm: CT

Dr. Yousem has provided the following report as a sample report for your reference. It does not match the case reviewed in the video.

STUDY: MRI BRAIN WITHOUT AND WITH CONTRAST.

INDICATION: 28-year-old male for evaluation of septic emboli on background of endocarditis.

COMPARISON: None available.

TECHNIQUE: Multiplanar multiecho imaging of the brain was performed without and with contrast.

FINDINGS:

Predominantly in the right posterior frontal and parietal lobes (with lesser degree of involvement of the occipital and temporal lobes) and extending into the sylvian fissure, there is inhomogeneous sulcal CSF FLAIR suppression with intrasulcal susceptibility. Additionally, there is corresponding cortical T2/FLAIR hyperintensity with areas of restricted diffusion and cortical enhancement. These findings are consistent with hemorrhagic meningoencephalitis. There is no discrete drainable collection. There is no mass effect or midline shift. There is minimal involvement of the contralateral left frontoparietal junction as well. There are a few other punctate foci of restricted diffusion in the white matter bilaterally, likely represent microembolic infarcts. There are a few small foci of T2/FLAIR hyperintensity in the white matter and basal ganglia bilaterally, likely representing gliosis from prior microembolic infarcts given patient's age and history.

There is no large territorial infarct. There is no mass, mass effect, or midline shift. The ventricles are normal in size, shape and configuration. Major intracranial arterial and venous sinus flow voids appear patent. The pituitary and stalk appear normal. Visualized paranasal sinuses and mastoid air cells are clear. The labyrinthine structures appear normal. The orbital contents appear normal.

IMPRESSION:

1. Findings in keeping with hemorrhagic meningoencephalitis centered in the right frontoparietal lobes, and minimal contralateral side involvement as detailed above. No discrete drainable collection. No mass effect or midline shift.

2. Scattered punctate acute and chronic microembolic infarcts in the white matter bilaterally.

Addendum:

The change is [a dilated vessel seen best on series 14 image 31, series 15 image 15, series 13 image 31 which may represent a mycotic aneurysm in the right perirolandic region. This would account for bleeding into the subarachnoid space which is maximal in the central sulcus region and the associated irritation of the cortex with possible meningeal infection. Follow-up examination with a CTA to confirm this finding is recommended versus conventional arteriography.]
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INDICATION: 28-year-old man with mitral valve endocarditis with MRI findings suggestive of mycotic aneurysm.

TECHNIQUE: Axial CTA scan images were performed of the head after administration of intravenous contrast. Multiplanar reconstructions in the sagittal and coronal plane were reviewed.

COMPARISON: MRI brain 4/17/2019.

FINDINGS:

Compared with the prior MRI at 8:03 PM, there is no significant change when accounting for differences in technique. CT angiography images demonstrate prominence of the MCA branches involving predominantly the right posterior frontal and parietal lobes with extension into the sylvian fissure. Hyperenhancement of the cortex/sulci in these areas that could be related to prominent vascular enhancement within partially effaced sulci superimposed with blood products noted on the previous MRI..

In the right perirolandic area, as noted on MRI, there is a focal, 3 mm focal outpouching (see Key images, series 7 slice 76) with a small vessel leading to this focal prominence, compatible with a small aneurysm.

No other similar focal areas of abnormal nodular enhancement is identified within the rest of the convexity sulci or related to the vasculature. Otherwise, no evidence of saccular intracranial aneurysm or flow-limiting stenosis in the proximal vessels of the circle of Willis. Apparent filling defect in the superior sagittal sinus (series 5/9) likely represents arachnoid granulation.

Normal ventricular size. No midline shift, mass, mass effect, or fluid collections. Patent basal cisterns.

Normal orbits. Clear paranasal sinuses. Clear mastoid air cells. Intact calvarium.

IMPRESSION:

1. Redemonstration of findings compatible with hemorrhagic change over the right frontoparietal lobes with partial sulcal effacement over the convexity and right sylvian fissure. No shift of midline structures noted.

2. Small 3 mm vessel outpouching in the perirolandic area, as described above, that is compatible with small mycotic aneurysm.

INDICATION:28 years old Male with Evaluate mycotic aneurysm, history of endocarditis.

TECHNIQUE: CT head without contrast and CT angiogram of the head was performed from the anterior arch of C1 to the vertex. 3D image analysis was performed.

COMPARISON: CT head dated 4/17/2019

FINDINGS:

CT head without contrast:

Minimal subarachnoid hyperdense material (15-30, 15-29), likely representing small residual subarachnoid blood products. Compared to the left side, there is diffuse sulcal effacement of the right frontal and right parietal lobes, likely representing parenchymal edema secondary to encephalitis. Although the prior CTA did not include precontrast brain imaging, based on the prior MRI also dated April 17, 2019 on T2 FLAIR imaging, there was diffuse subarachnoid hemorrhage within the right frontal and parietal perirolandic sulci including the right central sulcus. No new hemorrhage. No CT evidence of territorial infarction. Ventricular size and configuration are not significantly changed compared to prior exam. Basal cisterns are patent.

Orbits are unremarkable. Paranasal sinuses and mastoid air cells are clear.

CTA head:

Compared to the CTA dated 4/17/2019, there is no significant interval change. There is relative asymmetrical prominence of the MCA branches involving the right posterior frontal and parietal region. The vessels of the circle of Willis including the distal ICAs, MCA's, ACAs and PCAs are normal in caliber without any focal stenosis.

Redemonstration of the small previously seen saccular aneurysm in the right perirolandic region (9-70) that appears slightly more prominent on the current examination measuring approximately 4 mm diameter. No new aneurysms identified.

IMPRESSION:

1. Redemonstration of a small approximately 4 mm saccular aneurysm in the right perirolandic region (9-70) that is only minimally more prominent than on the prior exam. No definite new aneurysm identified.

2. Redemonstration of residual minimal subarachnoid blood products in the right frontoparietal sulci. No large intra-axial or extra-axial hemorrhage. Compared to the left side, there is diffuse effacement of the frontal and parietal sulci, likely resenting cerebral edema secondary to encephalitis. No significant midline shift. Basal cisterns are patent.