PMC10097901_01
Montage of CT images following intravenous contrast, outlining the arterial and venous angioarchitecture of the neck. (A) Axial slice through the C1 vertebra and odontoid peg show the narrowing and flattening of both internal jugular veins (block arrows) as they pass in front of the transverse processes of C1 (asterisks) on either side. The styloid process of the skull (thin arrow) can be seen on the right side. The internal carotid arteries are round in cross-section and situated more medially. (B) Axial slice through the thoracic inlet at the level of the left brachiocephalic vein (arrowheads) showing marked narrowing in front of the right brachiocephalic artery (BC, right brachiocephalic artery; AA, aortic arch). (C) In this coronal reconstruction, the internal jugular veins (IJVs) lie on the lateral side of the carotid arteries. They are out of the plane as they pass over the C1 transverse processes, but on the sagittal reconstruction (D), the distortion produced on the left side is evident (curved arrow = path of the left brachiocephalic vein, out of the plane in front of the left common carotid and right brachiocephalic arteries.). Numbers are transposed from pressures (cm H2O) recorded on catheter venography.
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F1
However, there was striking narrowing of both internal jugular veins anterior to the transverse processes of the C1 vertebra and marked narrowing of the left brachiocephalic vein between the sternum and the origins of the left common carotid and right brachiocephalic arteries (Figure 1).
Catheter venogram. Background-subtracted, oblique lateral view of the head and upper neck. Radiographic contrast injected through a catheter passed up through the left lateral sinus into the sagittal sinus outlines the sagittal, both lateral sinuses and upper jugular veins. There is a narrowing of both internal jugular veins (arrows) where they pass over the transverse processes of C1 (SSS, superior sagittal sinus; T, torcula; RTS, right transverse sinus; RSS, right sigmoid sinus; RIJV, right internal jugular vein) (Numbers = pressure recordings in cm H2O).
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There was no appreciable gradient across the narrowing of the left upper jugular vein (Figure 2).
Axial CT scans at the level of the C1 vertebra and odontoid peg following intravenous contrast injection, (A) at the baseline, (B) following resection of the right styloid and C1 transverse processes, and (C) following resection of the left C1 transverse process. The baseline scan (A) shows narrowing and flattening of both internal jugular veins (block arrows) as they pass in front of the transverse processes of C1 (asterisk) on either side. The styloid process of the skull (thin arrow) can be seen on the right side. (B) Following the right transverse process and styloid resections, the right internal jugular vein (block arrow) has expanded into the space created by the surgery. (C) Following left transverse process resection, the left internal jugular vein has now also expanded.
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On the left side, jugular and brachiocephalic vein narrowings were unchanged (Figure 3). However, her response to venoplasty suggested that there might yet be a benefit in relieving left jugular narrowing, and 2 years following her first surgical procedure she had the second, specifically, decompression of the left jugular vein by resection of the left C1 transverse process, leaving the styloid intact (Figure 3).