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computed_tomography_angiography

Computed tomography angiography

Computed tomography angiography (CTA) is a computed tomography technique used to visualize artery and veins throughout the body. This ranges from arteries serving the brain to those bringing blood to the lungs, kidneys, arms and legs.

With the development of CTA, MRA and 3D-DSA, more and more patients with intracranial aneurysms have been detected.

Computed tomography angiography is slowly replacing digital subtraction angiography as the first-line technique for the diagnosis and treatment planning of intracranial aneurysms, but digital subtraction angiography is still required in patients with diffuse subarachnoid hemorrhage (SAH) and negative initial computed tomography angiography 1).

Few studies have examined the risk of computed tomography angiography (CTA) during the acute phase of spontaneous intracerebral hemorrhage (ICH), while the benefits of CTA in ICH have been well-documented. The study from Hotta et al., investigated both the benefits of identifying CT angiography spot sign.

see Dynamic computed tomography angiography.

see Three dimensional computed tomography angiography.

see Four dimensional computed tomography angiography.

Subarachnoid hemorrhage

Brain death

Paraclinoid aneurysm

High-resolution thin-cut CTA is a fast and crucial tool for diagnosing paraclinoid aneurysms. The optic strut (OS) serves as an effective landmark in CTA source images for distinguishing between intradural and extradural paraclinoid aneurysms. The distal dural ring (DDR) is supposed to be located 2 mm above the base of the OS in axial planes 2).

Lower extremities

If patients presented with a weak or absent dorsalis pedis artery pulse, edema of both legs, and a past history related to vascular lesions of the lower limbs, they evaluated the veins and arteries of the lower extremities using Doppler sonography. If abnormal vascular findings were detected, computed tomography angiography (CTA) of the lower extremities was performed. Radiologic and clinical risk factors of concomitant occlusive arterial lesions of the lower limb were analyzed by logistic regression analysis.

In 2013, 335 patients suspected of having vascular lesions underwent Doppler sonography. Among them, CTA of the lower extremities was performed in 58 patients. The mean age was 69.4 years (35 men and 23 women). Severe narrowing or total occlusion of the leg arteries was detected in 23 patients. Partial obstructive arterial disease of the legs was detected in 14 patients. Occlusion but with good collateral circulation of the leg was found in three patients. Surgical treatment plans were cancelled or changed in 28 patients. The risk factors for occlusive arterial lesions of the legs were an abnormal ankle-brachial pressure index (ABPI), absent dorsalis pedis artery pulse, and lack of response after a pain-blocking procedure.

If patients present with a weak or absent dorsalis pedis artery pulse, abnormal ABPI ratio, and no response after a pain-blocking procedure, the clinician should consider the possibility of severe arterial occlusion of the legs. They suggest that the differential diagnosis of obstructive arterial lesions of the legs from lumbar degenerative diseases is important to prevent unnecessary invasive surgical treatment of the lumbar spine 3).


A study confirms that people with symptomatic LSS, neurogenic claudication, walking limitations and LSS-related disability are extremely sedentary, and are not meeting guidelines for physical activity. There is an urgent need for interventions aimed a reducing sedentary behaviour and increasing the overall level of physical activity in LSS, not only to improve function but also to prevent diseases of inactivity. This study suggests that reducing sedentary time, increasing time spent in light intensity activity, and increasing time spent in higher intensities of light activity may be appropriate as initial goals for exercise interventions in people with symptomatic LSS and neurogenic claudication, transitioning to moderate activity when appropriate. Results of this study also demonstrate the importance of employing disease specific measures for assessment of performance in LSS, and highlight the potential value of these methods for developing targeted and realistic goals for physical activity. Physical activity goals could be personalized using objective assessment of performance with accelerometry. This study is one step toward a personalized medicine approach for people with LSS, focusing on increasing physical function 4).

Problems

Flat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to degradation of image quality and are a significant problem.

When an intravenous contrast protocol is used, metal artifact reduction (MAR) significantly ameliorates the assessability of brain parenchyma, vessels, and treated aneurysms in patients with intracranial coils or clips 5).

1)
de Oliveira Manoel AL, Mansur A, Murphy A, Turkel-Parrella D, Macdonald M, Macdonald RL, Montanera W, Marotta TR, Bharatha A, Effendi K, Schweizer TA. Aneurysmal subarachnoid haemorrhage from a neuroimaging perspective. Crit Care. 2014 Nov 13;18(6):557. doi: 10.1186/s13054-014-0557-2. Review. PubMed PMID: 25673429; PubMed Central PMCID: PMC4331293.
2)
Liao CH, Lin CJ, Lin CF, Huang HY, Chen MH, Hsu SP, Shih YH. Comparison of the effectiveness of using the optic strut and tuberculum sellae as radiological landmarks in diagnosing paraclinoid aneurysms with CT angiography. J Neurosurg. 2016 Jan 8:1-8. [Epub ahead of print] PubMed PMID: 26745492.
3)
Lee DC, Heo DH, Cho KS. Concomitant Occlusive Vascular Lesions of Legs in Patients with Degenerative Lumbar Diseases: Do These Lesions Influence Treatment? J Neurol Surg A Cent Eur Neurosurg. 2018 Sep 17. doi: 10.1055/s-0038-1669474. [Epub ahead of print] PubMed PMID: 30223290.
4)
Norden J, Sinha A, Smuck M, Tomkins-Lane C, Hu R. Objective measurement of free-living physical activity (performance) in lumbar spinal stenosis: are physical activity guidelines being met? Spine J. 2016 Oct 25. pii: S1529-9430(16)31023-3. doi: 10.1016/j.spinee.2016.10.016. [Epub ahead of print] PubMed PMID: 27793759.
5)
Pjontek R, Önenköprülü B, Scholz B, Kyriakou Y, Schubert GA, Nikoubashman O, Othman A, Wiesmann M, Brockmann MA. Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment. J Neurointerv Surg. 2015 Sep 7. pii: neurintsurg-2015-011787. doi: 10.1136/neurintsurg-2015-011787. [Epub ahead of print] PubMed PMID: 26346458.
computed_tomography_angiography.txt · Last modified: 2018/09/19 08:30 by administrador