Background Lung perfusion defects (PDs) have been described in COVID-19 using dual-energy computed tomography pulmonary angiography (DE-CTPA). We assessed the prevalence and characteristics of PDs in COVID-19 patients with suspected pulmonary embolism (PE) and negative CTPA. Methods This retrospective study included COVID-19 and non-COVID-19 pneumonia groups of patients with DE-CTPA negative for PE. Two radiologists rated the presence of PD within the lung opacities and analyzed the type of lung opacities and PD pattern (i.e. homogeneous or heterogeneous). The clinical, biological, radiological characteristics including time from first symptoms and admission to DE-CTPA, oxygen requirements, CRP, D-dimer levels, duration of hospital admission and death were compared within the COVID-19 group between patients with (PD +) or without PD (PD-). Results 67 COVID-19 and 79 non-COVID-19 patients were included. PDs were more frequent in the COVID-19 than in the non-COVID-19 group (59.7% and 26.6% respectively, p < 0.001). Patterns of PDs were different, with COVID-19 patients exhibiting heterogenous PDs (38/40, 95%) whereas non-COVID-19 patients showed mostly homogeneous perfusion defects (7/21 heterogeneous PDs, 33%), p < 0.001. In COVID-19 patients, most consolidations (9/10, 90%) exhibited PDs while less than a third of consolidations (19/67, 28%) had PDs in non-COVID-19 patients. D-dimer, oxygen levels and outcome were similar between COVID-19 PD + and PD- patients; however, time between admission and DE-CTPA was longer in PD + patients (median [IQR], 1 [0–7] and 0 [0–2]; p = 0.045). Conclusion Unlike in bacterial pneumonia, heterogeneous PDs within lung opacities are a frequent feature of COVID-19 pneumonia in PE-suspected patients.
A 33-year-old woman underwent autologous fat injection in the left orbit during reconstructive eye surgery before replacement of an infected eye prosthesis. Past medical history was uneventful except for anophthalmia since age 6, responsible for several operations over the past decade. After removal of the infected prosthesis, a partial reconstruction of the orbit was performed. Eight 1-mL syringes, each containing 1 mL of autologous fat were injected, two into the margo orbitalis region, and the six others into the orbital cavity. No cardiac arrhythmia or drop of blood pressure was recorded during surgery or the postoperative period. Upon awakening, the patient presented a complete right hemiplegia.Brain MRI revealed a large cerebral infarction in the left middle cerebral artery (MCA) territory ( Fig. 1). Cervical and transcranial ultrasonography, transthoracic and transoesophageal echocardiography, 24 h-Holter ECG and the biological workup were all normal. In addition to cerebral ischemia, MRI showed the presence of T1-hyperintensive abnormalities, both in the left cavernous sinus and in several distal branches of the left MCA. These abnormalities disappeared on sequences with fat saturation, confirming their fatty nature and leading to the diagnosis of stroke due to fat emboli ( Fig. 1).Stroke after autologous fat injection in cosmetic surgery of the face has been exceptionally reported [1][2][3][4]. In these cases, fundoscopic examination was diagnostic, showing occlusions of distal branches of the retinal artery with fat emboli. To our knowledge, stroke complicating a reconstructive eye surgery has not been reported to date. In the present case, fundus could not be examined (anophtalmia) but MRI was the diagnostic tool, demonstrating the presence of fatty particles in cerebral arteries.The mechanism by which extravascular injection of fat during reconstructive surgery of the face can provoke ischemic stroke remains speculative. It has been shown using conventional angiography that inactive anastomoses between external and internal carotid arteries may become functionally active if pressure in external carotid artery branches is increased [5]. Fatty particles could enter the external carotid artery system directly by intravasation before reaching the internal carotid artery retrogradely by reopening of the anastomoses cited above. Three preconditions are supposed to favor intravasation of fat, namely, the presence of well vascularized tissues, fragmentation of the parenchyma associated with vascular breaches (for example in the case of infected tissue), and local pressure increase [2]. Our patient fulfilled these preconditions since orbital structures are hypervascularized, the procedure was septic with tissues already fragmented by previous reconstructions, and repeated injections during the procedure certainly increased the intraorbital pressure. The amount of fat injected, the applied force during injections and the velocity of these injections seem also to be factors that raise the risk of fat emboli duri...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.