Clinical and Radiological Profiles of COVID-19 Patients with Neurological Symptomatology: A Comparative Study

Abstract

Patients with COVID-19 can require radiological examination, with chest CT being more frequent than neuro-imaging. The objective is to identify epidemiological, clinical and radiological factors considered as predictors of neurological involvement in patients with COVID-19 assessed by neuroimaging and to describe the neuroimaging findings. This retrospective study was performed with 232 consecutive confirmed COVID-19 patients, from two radiological units, which were divided into two groups: (1) those who underwent a brain CT/MRI scan (n = 35) versus (2) those who did not undergo the brain CT/MRI scan, but underwent only chest CT (n = 197). There was a statistically significant difference with associations regarding the COVID-19 brain scan group for: admission to ICU, greater severity of lung injuries, the use of a mechanical ventilator and sepsis. Statistical tendency was found for chronic renal failure and systemic arterial hypertension. Forty-percent of COVID-19 patients from the brain scan group were abnormal on brain CT and/or brain MRI (22.9% of the cases with bleeding or microbleeding, 8.6% with restricted diffusion lesions). One ischemic stroke case was associated with irregularity at the M1 segment of the right middle cerebral artery. There was a case of left facial nerve palsy with enhancement of the left geniculate ganglia. An analysis of the olfactory bulbs was possible in 12 brain MRIs and 100% had enhancement and/or microbleeding. In conclusion, a more severe COVID-19 disease from ICU, a more severe form of lung disease, the use of mechanical ventilator and sepsis were associated to the COVID-19 patients with neurological involvement who had undergone brain scans. Microvascular phenomenon was a frequent finding in the brain and olfactory bulbs evaluated by neuroimaging.

Keywords: COVID-19; CT; MRI; brain; olfactory bulb; radiology; risk factors; stroke.

Figure 1

Block Diagram of the proposed research.

Figure 2

Moments during the performance of MRI on the brain of a patient with COVID-19 (A) Patient being positioned in the MRI machine with the brain coil having been placed. (B) Photograph of the MRI Control Room during the examination and the acquisition of the brain magnetic resonance images of a patient with COVID-19.

Figure 3

Moments during the performance of a chest computerized tomography of a COVID-19 patient. (A) Patient being positioned in the computerized tomography machine for chest examination without contrast. (B) Photograph of the Computerized Tomography Machine Control Room during a computerized tomography examination of the chest of this patient.

Figure 4

Case 31—The Chest CT on admission shows areas of alveoellar consolidation and ground glass in more than 50% of lung area (arrows A,C,E). Three days later, there was a severe increase of the lung disease (arrows, B,D,F). The brain MRI shows some hyperintense small areas on FLAIR (arrows, G) and in DWI (arrows, H) which are hypointense on ADC-Map (restricted diffusion lesions, arrows, I) in both cerebral hemispheres. Small areas of microbleeding are observed, being hyperintense on T1WI (J, arrows) and hypointense on T2* (K, arrows) localized on the medial part of left pre and postcentral gyrus. There is also a large oval hematoma located at the vermis of the cerebellum, being hyperintense on sagittal T1 (L, arrow) and on coronal T2WI (M, arrow) with peripheric hypointense ring of hemosiderin. Some small lesions, which represent microbleeding (methemoglobin), are also located on the splenium of the corpus callosum hyperintense on FLAIR (N, arrow) and on DWI (O, arrow) being hypointense on T2* (P, arrow). The CT (Q–U) without contrast made one month later showed that the lesions described above on previous MRI are hypointense and that a new sequel in the right parietal lobe (S,T, arrow) had appeared.

Figure 5

Case 30—The brain MRI shows multiple and confluent areas of diffuse hyperintensity on FLAIR (A–C, arrows) and liquid in the mastoid cells (A, short head of arrows). A small linear hyperintense subcortical on sagittal T1 (D, arrow), which represents methemoglobin, is observed. There are multiple small dots of micro bleeds at the cerebellum and middle cerebellar peduncle (E, arrows), intern capsule (F, long arrows), splenium of corpus callosum (F, head of arrow) and subcortical white matter (F,G, arrows) of the brain. The 3D chest CT reconstruction shows that there is more than 50% of opacification in both lungs (H).

Figure 6

Case 18—On MRI, there is a small round lesion on the splenium of the corpus callosum which could represent a cytotoxic lesion due to a cytokine storm and differential diagnosis is with small acute infarct. It is hypointense on T1 (A, arrow) with restricted diffusion, being hyperintense on DWI (B, arrow) and hypointense on ADC-Map (C, arrow). This lesion is also hyperintense on FLAIR (D, arrow) and T2* (E, arrow) without microbleeding. The olfactory bulbs are hyperintense on coronal post contrast fat suppressedT1WI (F, arrows) in comparison to the gray matter of the frontal lobes, which can represent enhancement, but we cannot exclude microbleeding.

Figure 7

Case 34—The MRI shows a predominantly chronic ischemic stroke, located in the cortical and subcortical region of the right middle cerebral artery territory (M8 and M10) (A–F, long arrows). In the right M10 territory, the lesion has a small hyperintense “line” on T1 (A, short arrow) probably methemoglobin; the cortical enhances with contrast (B, long arrows); is hyperintense on T2 and T2*(C,D, long, arrow), being hyperintense in DWI (E, long arrows) and hyperintense on ADC-Map (F, long arrows), representing facilitates diffusion (T2 shine through effect). However, there is still a small area in M10 lesions that shows restricted diffusion of probably more recent ischemic injury being hyperintense in DWI (E, small arrow) and hypointense in ADC-Map (F, small arrow). There are small areas of bleeding with magnetic susceptibility in T2 * (D, arrow head) located in the medial cortical of the right cerebral hemisphere and in the left wall of hypothalamus (G, arrow) which is reduced in volume on coronal T2WI (H, arrow). On the angio MRI, parietal irregularity and narrowing in the right M1 is observed (I,J, arrow) and also in the origin of right anterior artery. Small dot of hyperintensity in the right olfactory bulb (K, arrow) observed on pre contrast fat suppressed T1WI, which seems have increased signal with contrast (L, arrow) representing probably methemoglobin and enhancement.

Figure 8

Case 32—The MRI shows both hypointense geniculate ganglions on axial fat suppressed T1 WI (A, arrows), but the left geniculate ganglion has abnormal stronger enhancement on axial post contrast (B, arrow) fat suppressed T1 WI. The coronal fat suppressed T1 WI shows olfactory bulbs with normal hypointense signal (C, arrows), but the post contrast coronal fat suppressed T1WI shows abnormal enhancement in the right olfactory bulb (D, arrow).

Figure 9

Case 27—On MRI, there is a subcortical hematoma located respectively in transition between left posterior temporal lobe and occipital lobe (long arrow A–D) with hyperintense methemoglobin inside on T1WI (A, long arrow), FLAIR (B, long arrow), DWI (C, long arrow) and T2* (D, long arrow) and with hemosiderin in the periphery being hypointense ring. There is vasogenic edema near the left temporal hematoma being hyperintense on FLAIR (B, short arrow). There is also microbleeding in pale globes (A,D, short arrows). Another cortical hematoma in the right parietal lobe (E–H, long arrow), with the same characteristics described above with methemoglobin inside and hemosiderin in the periphery. There are small dots of subcortical microbleeding in the left frontal and parietal lobes (H, short arrows). Two months later there was regression on MRI (I–P) of both hematomas in size, but deposition of hemosiderin remained being hypointense on all sequences [T1, (I and M); FLAIR, (J); DWI, (K,O, arrow); T2, (N, arrow); and T2* (L,P arrows)] and in the lentiform nuclei (L, small arrows).

Figure 10

Case 27—The Chest CT shows more than 50% of typical lung opacity of COVID 19 pulmonary injury, bilaterally (A, arrows). The MRI shows hyperintense lesion on 3D FLAIR (B, arrow) [16] and also on pre (C, arrow) [16] and post contrast SPGR T1 WI (D, arrow) [16]. This is suggestive of component of probably methemoglobin in this left olfactory bulb lesion which seems be little bigger and asymmetric compared with the apparently normal right olfactory bulb. This asymmetry in size is better seen on FLAIR (B) [16]. There is also a small round hyperintense lesion in the subcortical white matter in the left frontal lobe on FLAIR (B, short arrow) which is hypointense on T1WI (C, short arrow) and does not enhance on post-contrast T1WI (D, short arrow) being nonspecific [16]. The MRI performed 3 months later shows on pre contrast fat suppression T1 WI (E) that there is reduction on hyperintensity of the left olfactory bulb lesion.