ABSTRACT
Right-to-left shunting is usually associated with congenital conditions involving the heart, lungs, and the blood vessels that connect both organs. It is demonstrated by echocardiography, transesophageal ultrasound, CT scan, MRI and more definitively by conventional angiography. In this paper, we present a 16-year old female who manifested with progressive dyspnea, persistent cyanosis and decreased arterial oxygen saturation. Clinical assessment and arterial blood gas parameters suggested the presence of significant shunting. However, cardiac evaluation showed no intracardiac defects. High resolution CT scan of the chest with CT angiography of the pulmonary artery also showed no evidence of pulmonary vascular malformation or shunt anomaly. Lung perfusion scintigraphy performed after intravenous administration Tc99m-MAA showed tracer uptake in the brain, spleen and kidneys signifying the presence of a right-to-left shunt in the lungs. Cardiac catheterization later demonstrated the presence of primary pulmonary telangiectasia.
Subject(s)
Humans , Female , Adolescent , Administration, Intravenous , Cardiac Catheterization , Cyanosis , Dyspnea , Echocardiography , Pulmonary Artery , Technetium Tc 99m Aggregated Albumin , Telangiectasis , Vascular Malformations , Diagnosis , Diagnostic Imaging , Radionuclide Imaging , Diagnostic Techniques and ProceduresABSTRACT
Congenital lobar emphysema (CLE) is a life-threatening but potentially reversible lung abnormality of unknown etiology that can present a diagnostic dilemma. Imaging procedures are helpful for early diagnosis. This paper aims to present the scintigraphic features of CLE in a two-year-old male in correlation with other diagnostic modalities. Lung perfusion scintigraphy revealed globally diminished perfusion to the left lung. High Resolution Computed Tomography (HRCT) of the chest showed intrinsic narrowing of the distal left mainstem bronchus. CT scan of the Pulmonary Arteries (CTPA) showed a small left main pulmonary artery. Lung perfusion scintigraphy in CLE is characterized by markedly attenuated vascularity of the involved lobe with consequent decreased perfusion, and increased to normal perfusion in the unaffected lobe. It plays a vital role in the early diagnosis and management of pediatric pulmonary diseases presenting with a diagnostic dilemma, particularly in cases where it can preclude more invasive diagnostic procedures.
Subject(s)
Humans , Male , Child , Bronchi , Early Diagnosis , Lung , Perfusion Imaging , Pulmonary Artery , Pulmonary Emphysema , Tomography, X-Ray ComputedABSTRACT
PURPOSE: Differential diagnosis between arteriovenous (AVMs) and non-arteriovenous malformations (nAVMs) is important in patients with congenital vascular malformations, because AVMs can cause hemodynamic alteration and require immediate treatment. We investigated whether transarterial lung perfusion scintigraphy (TLPS) was useful for the diagnosis and post-therapeutic evaluation of AVMs in extremities. MATERIALS AND METHODS: Fifty-seven patients (M:F=26:31, 21+/-13 yr, 9 upper and 48 lower extremities) suspected of congenital vascular malformations in extremities underwent TLPS using 99mTc-MAA before embolization/sclerotherapy. Dose-corrected shunt fraction (SF) was calculated from time-activity curve of the lung. Final diagnosis of AVMs was determined by angiography. In patients with AVMs, follow-up TLPS was done for post-therapeutic evaluation. RESULTS: Sixteen patients (8 upper and 8 lower extremities) had AVMs, while the remaining 41 had nAVMs (1 upper and 40 lower extremities). The mean SF of AVMs on TLPS was significantly higher than that of nAVMs (66.4+/-25.8% vs. 2.8+/-4.3%, p=0.003). The sensitivity, specificity, and accuracy of TLPS (cut-off of SF = 20.0%) in diagnosis of AVMs before treatment were 93.8% (15/16), 100% (41/41) and 98.2% (56/57), respectively. The follow-up TLPS and angiography for post-therapeutic evaluation showed concordant results in 13 of 16 patients (81.3%) with AVMs. The mean SF of TLPS was significantly decreased after embolization/sclerotherapy (69.5+/-24.0% vs. 41.0+/-34.7%, p=0.01). CONCLUSION: TLPS provides hemodynamic information of AVMs in extremities semiquantitatively. Furthermore, the results of TLPS showed a high concordance rate with angiographic findings. Therefore, TLPS is useful for the diagnosis and post-therapeutic evaluation of AVMs in extremities.