PMC6361750_01
The results of different imaging during the first hospitalization. (A) First CDFI showed the right ICA was normal. (B) CTA showed the right ICA occluded. (C) Second CDFI showed a hypoechoic mass was attached to the anterior wall of initial segment of the right ICA (arrow); (D) MRI T1-weighted imageing showed no signal in the intracranial segment of the right ICA (arrow); (E) DSA showed right ICA was normal.
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F1
The initial CDFI was performed on day 1 of hospitalization, which revealed a patent right ICA with normal blood flow velocity (Figure 1A). However, CTA on day 2 indicated that the right ICA was occluded (Figure 1B). A repeat CDFI scan on day 4 of hospitalization revealed a hypoechoic mass [thickness 2.8 mm (suspected thrombus)] was attached to the anterior wall of the initial segment of the right ICA (Figure 1C). Magnetic resonance imaging (MRI) was performed on day 6; T1-weighted imaging showed that the intracranial segment of the right ICA was invisible, indicating that the right ICA was occluded (Figure 1D). However, digital subtraction angiography (DSA) performed on the same day revealed that the right ICA was normal, with no significant stenosis in any segment (Figure 1E).
The results of CTA and 3-D CT reconstruction during the second hospitalization. (A,B) The sagittal (A) and axial (B) imaging of CTA showed the right ICA became significantly narrow (arrow) due to styloid process compression; (C) 3-D CT reconstruction imaging showed bilateral styloid process were overgrown.
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F2
Repeat CTA revealed severe stenosis of the right ICA, and the sagittal image revealed the right styloid process compressing the right ICA horizontally at the C2-3 intervertebral disc (Figures 2A,B). Subsequent 3D computed tomography reconstruction of the cervical spine revealed a bilateral overgrown styloid processes, which was ~6.3 cm in length on the right side and 6.1 cm on the left side (Figure 2C).
The results of CDFI during the second hospitalization. (A) Two-dimensional gray-scale imageing showed a long hyperechoic segment on the right side of neck: styloid process (arrows); (B) CDFI showed the right ICA was oppressed by the styloid process (arrow); (C) The blood flow velocity in right ICA in normal position: PSV = 72 cm/s, EDV = 33 cm/s; (D) The blood flow velocity in right ICA increased when the patient slowly turned head to the right: PSV = 204 cm/s, EDV = 113 cm/s. PSV, peak systolic velocity; EDV, end diastolic velocity.
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F3
Subsequently, CDFI depicted a long hyperechoic bony structure on the right side of the neck (Figure 3A), located between the base of skull and the ICA compressing the ipsilateral ICA causing visible artery stenosis (Figure 3B). Blood flow velocity in the ICA dramatically increased when the patient slowly turned his head to the right (Figure 3D), which was significantly altered compared with the normal position (Figure 3C).
TCD real-time monitoring of blood flow changes in bilateral MCA and postoperative CDFI. (A) In normal position, RMCA: PSV = 8 2 cm/s, EDV = 27 cm/s; LMCA: PSV = 108 cm/s, EDV = 43 cm/s. (B) Turning his head to the right, RMCA: PSV = 57 cm/s, EDV = 28 cm/s; LMCA: PSV = 109 cm/s, EDV = 49 cm/s. (C) Turning his head backwards, RMCA: PSV = 111 cm/s, EDV = 41 cm/s. LMCA: PSV = 1 06 cm/s, EDV = 41 cm/s. (D) When the patient turned his head slowly continuously, a visible change of the right MCA and no significant change on the left. (E) The right styloid process specimen. (F) CDFI detected the styloid process stump (arrow).
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F4
Even when the patient was in a normal position, blood flow velocity in the right MCA was lower than in the left, but, nevertheless, remained in the normal range (Figure 4A). When the patient turned his head to the right, blood flow velocity in right MCA was significantly decreased (Figure 4B), but increased significantly when he turned his head back to the starting position (Figure 4C). Blood flow velocity in the left MCA did not change markedly during these maneuvers (Figures 4A-C). When the patient turned his head slowly and continuously, blood flow velocity in the right MCA changed dramatically, with no significant change on the left side (Figure 4D). The middle and lower part of the overgrown styloid process was removed; the length of the specimen was approximately 4.2 cm (Figure 4E). Postoperatively, the right styloid process stump was detected and patency in the right ICA was restored (Figure 4F).