Comparison of chest radiography and chest CT for evaluation of pediatric COVID-19 pneumonia: Does CT add diagnostic value?

PURPOSE: First, to investigate the added diagnostic value of chest computed tomography (CT) for evaluating COVID-19 in symptomatic children by comparing chest CT findings with chest radiographic findings, and second, to identify the imaging signs and patterns on CT associated with COVID-19 pneumonia in children. MATERIALS AND METHODS: From March 2020 to December 2020, 56 consecutive children (33 males and 23 girls; mean age ± SD, 14.8 ± 5.0 years; range, 9 months-18 years) with mild to moderate symptom and laboratory confirmed COVID-19 (based on Centers for Disease Control criteria) underwent both chest radiography and chest CT on the same day within the first 2 days of initial presentation to the hospital. Two experienced radiologists independently evaluated chest radiographs and chest CT studies for thoracic abnormalities. The findings from chest radiography and chest CT were compared to evaluate the added diagnostic value of chest CT for affecting patient management. Interobserver agreement was measured with Cohen's κ statistics. RESULTS: Eleven (19.6%) of 56 patients had abnormal chest radiographic findings, including ground-glass opacity (GGO) in 5/11 (45.4%) and combined GGO and consolidation in 6/11 (54.5%). On chest CT, 26 (46.4%) of 56 patients had abnormal CT findings, including combined GGO and consolidation in 19/26 (73.1%), GGO in 6/26 (23.1%), and consolidation in 1/26 (3.8%). Chest CT detected all thoracic abnormalities seen on chest radiography in 11/26 (42.3%) cases. In 15/26 (57.7%), chest CT detected lung abnormalities that were not observed on chest radiography, which included GGO and consolidation in 9/15 (60%), GGO in 5/15 (33.3%), and consolidation in 1/15 (6.6%) cases. These additional CT findings did not affect patient management. In addition, chest CT detected radiological signs and patterns, including the halo sign, reversed halo sign, crazy paving pattern, and tree-in-bud pattern. There was almost perfect interobserver agreement between the two reviewers for detecting findings on both chest radiographs (κ, 0.89, p = .001) and chest CT (κ, 0.96, p = .001) studies. CONCLUSION: Chest CT detected lung abnormalities, including GGO and/or consolidation, that were not observed on chest radiography in more than half of symptomatic pediatric patients with COVID-19 pneumonia. However, these additional CT findings did not affect patient management. Therefore, CT is not clinically indicated for the initial evaluation of mild to moderately symptomatic pediatric patients with COVID-19 pneumonia.

Selective and super-selective C-arm based cone beam CT angiography (CBCTA) with DynaCT for CyberKnife radiosurgery planning of intracranial arteriovenous malformations (AVMs).

BACKGROUND: Successful radiosurgery for intracranial arteriovenous malformations (AVMs) requires accurate delineation of the nidus in 3D. Exact targeting and precise equipment is needed to achieve obliteration of the nidus while minimizing toxicity to the surrounding brain. In some micro-AVMs and poorly visible AVMs we have used cone beam CT angiography (CBCTA) with selective and super-selective angiography where a micro-catheter is advanced into the feeding arteries- to assist with nidus definition for CyberKnife radiosurgery planning. METHODS: Four patients who had AVMs inadequately visualized with MRI, MRA, CT, CTA, and dynamic CT angiography (dCTA) were identified for selective angiography (2 had super-selective angiography) for CyberKnife radiosurgery. The mean age at the time of treatment was 45 years (range: 22 - 71 years). All patients had suffered prior hemorrhage and were deemed inoperable. Super-selective angiography was done under general anesthesia to minimize motion artefact and the risk of arterial dissection. Angiography was performed using the biplane angiographic suite (ArtisQ; Siemens). Cone beam reconstructions were performed using DynaCT software. For each scan, volumetric data was acquired over 20 seconds in a single rotation of the C-arm mounted flat-panel detector cone-beam CT system. The data set was imported into the CyberKnife TPS and co-registered with the treatment planning CT, T2 MRI and Toshiba dCTA. Delineation of the AVM nidus was performed by the multi-disciplinary AVM team. RESULTS: There were no adverse events related to the angiography or radiosurgery treatment. CBCTA data sets created using DynaCT were accurately co-registered with the treatment planning scans in the CyberKnife treatment planning system (Multiplan). For all 4 patients, feeding arteries, draining veins and nidi were clearly visualized and used to develop radiosurgery plans. Mean nidus size was 0.45cc (range: 0.07 - 1.00cc). CONCLUSIONS: For intracranial micro-AVMs and AVMs otherwise poorly visualized using DSA, MRA, CTA or dCTA, selective and super-selective CBCTA images (created using DynaCT) can be successfully imported into the CyberKnife TPS to assist in nidus delineation. Advancement of a micro-catheter into the feeding arteries to allow continuous contrast injection during volumetric scanning constitutes super-selective CBCTA. This technique provides superior visualization of micro-AVMs and should be utilized for radiosurgery planning of poorly visualized AVMs.

Endovascular glue embolization of a radiation-induced lenticulostriate artery pseudoaneurysm in a pediatric patient with optic pathway glioma: Case report and review of literature.

Radiation-associated vascular changes most commonly present in the form of stenosis, thrombosis and occlusion. However, development of intracranial aneurysms secondary to radiation is far less common and often manifests with rupture. These aneurysms are difficult to treat and associated with high morbidity and mortality when ruptured compared with saccular aneurysms unrelated to radiation treatment. Both surgical and endovascular options are available for treatment of these aneurysms. We present a young patient with a radiation-induced intracranial pseudoaneurysm arising from the lenticulostriate branch of the left middle cerebral artery (MCA); this developed 1 year 4 months after 59.4 Gy of focused radiation to the suprasellar pilomyxoid astrocytoma. The patient successfully underwent endovascular glue embolization of the aneurysm and occlusion of the lenticulostriate artery after unsuccessful trapping of the aneurysm and occlusion of the parent artery using coils. She developed transient hemiparesis of the right side following the procedure, which was managed conservatively. We performed a complete review of the literature dealing with the radiation-induced intracranial aneurysms, their presentation, treatment and outcome.