Cardiac Shunt Assessment in Children with Macroaggregated Albumin Technetium-99m

Gates, Gary F.; Orme, Harry W.; Dore, Earl K.

doi:10.1148/112.3.649

Cited by 34 publications

(7 citation statements)

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“…The estimated RLS ratio was 40.8%, and the radioactive ratio of the brain to the whole body was 1.7%. 1,5,6 There were no clinically detectable neurological changes after the injection of MAA. Tc-99m HMPAO SPECT was performed two weeks after the perfusion study, and it revealed hypoperfused areas in the left Fig.…”

Section: Casementioning

confidence: 92%

“…11 Lung and total-body imaging with Technetium99m-macroaggregated albumin (Tc-99m MAA) has been used to elucidate pulmonary perfusion and/or systemic circulation, and to estimate the magnitude of intracardiac RLS in cyanotic children with complex congenital heart disease. [1][2][3][4][5][6][7][8][9][10] In the presence of RLS, MAA particles reach the systemic circulation to lodge in the capillary beds of the end extrapulmonary organs, 1,a-6,8,10 and distribution of these radioparticles therefore supposedly reflects normal or abnormal perfusion in the depicted organs. In this paper, we described unusual or unexpected abnormalities in cerebral perfusion demonstrated by Tc-99m MAA total-body scanning in two children with complex con- Fig.…”

Section: Introductionmentioning

confidence: 99%

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Abnormal brain perfusion demonstrated by Tc-99m MAA total-body scan in two children with complex congenital heart disease

et al. 1998

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This paper describes abnormal brain perfusion unexpectedly demonstrated by Tc-99m MAA total-body imaging in two children with intracardiac right-to-left shunt (RLS) associated with complex congenital heart disease. One child was a 12-year-old girl with asplenia cardiac syndrome and multiple cerebral infarctions caused by thromboembolism in the internal carotid artery, and the other child was a 6-month-old boy who developed focal cerebral infarction following shunt operation. In both children, the total-body imaging depicted the brain due to RLS, where radioactivity decreased unilaterally in the cerebral hemisphere. In the first patient, radioactivity also decreased in the contralateral cerebellum, suggesting the crossed cerebellar diaschisis phenomenon. These abnormalities in brain perfusion were confirmed by Tc-99m HMPAO brain SPECT. Careful review of the distribution of the radiotracer in the depicted brain on Tc-99m MAA total-body imaging may provide important information regarding brain perfusion in some patients with a high risk of stroke complication associated with RLS.

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Section: Casementioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Abnormal brain perfusion demonstrated by Tc-99m MAA total-body scan in two children with complex congenital heart disease

et al. 1998

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“…The percentage of radiolabelled macroaggregates shunted from pulmonary to systemic circulation was calculated by the equation proposed by GATES et al [12]: This is a quantitative measure of the percentage of cardiac output flowing through vessels >15 µm in diameter. This method has been documented to give estimates of shunt that closely correspond with those measured by the classical O 2 method, both in pulmonary disease with known large arterio-venous (A-V) malformations [13] and in intracardiac right-left (R-L) shunts [12]. Using the same batch of macroaggregates, whole body scintiscans were performed on two patients with suspected pulmonary emboli on days 1 and 3, and the calculated shunt estimates were 3 and 4%, respectively.…”

Section: Subject and Methodsmentioning

confidence: 99%

Pulmonary vascular dilatation and diffusion-dependent impairment of gas exchange in liver cirrhosis

Crawford¹,

Regnis²,

Laks³

et al. 1995

Eur Respir J

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the actual presence of diffusion-limitation for oxygen. Thus, significant inequality of alveolar ventilationperfusion ratios (V'A/Q') could equally explain a marked improvement in arterial Pa,O 2 with 100% oxygen breathing. Indeed, recent studies using the multiple inert gas elimination technique (MIGET), an analysis which can indirectly detect oxygen diffusion-limitation, have attributed the arterial hypoxaemia in patients with liver cirrhosis to V'A/Q' inequality and intrapulmonary shunting [9][10][11]. However, none of these MIGET studies has providedany direct evidence of actual pulmonary vascular dilatation; and, hence, they do not, by themselves, invalidate the specific hypothesis that diffusionlimitation for oxygen can occur as a direct consequence of abnormal dilatation of interalveolar vessels.To adequately test the above hypothesis requires an experimental approach that has the power to simultaneously Eur Respir J, 1995, 8, 2015-2021 DOI: 10.1183 ABSTRACT: To test the hypothesis that diffusion-limitation for oxygen is due to abnormal vascular dilatation and significantly contributes to the arterial hypoxaemia of liver cirrhosis requires an experimental approach that detects both diffusion-limitation for oxygen and the presence of abnormal dilatation of pulmonary vessels exposed to alveolar gas. We therefore studied the gas exchange of a 64 year old man with alcoholic liver cirrhosis and severe resting arterial hypoxaemia (arterial oxygen tension (Pa,O 2 ) 7.5 kPa) whilst breathing air and 100% O 2 using conventional blood gas (CBG) analysis, the multiple inert gas elimination technique (MIGET) and whole body scintigraphy (WBS) following the i.v. administration of radiolabelled boli of macroaggregates with a minimum diameter of 15 µM.During air breathing, there was a consistently positive difference between the arterial oxygen tension predicted by MIGET and that actually measured (P-M Pa,O 2 , average 0.9 kPa). During O 2 breathing, P-M Pa,O 2 became negative, (average -12.2 kPa), and shunt estimated by the O 2 method (% of Q') was consistently less than that measured by MIGET. Whereas both O 2 method and MIGET estimates of shunt never exceeded 25%, the WBS shunt was 40%, indicating that a substantial fraction of cardiac output flowed through abnormally dilated pulmonary vessels, some of which were exposed to alveolar gas and, hence, participated in gas exchange.Although our observations pertain to one subject, we believe they provide the most convincing in vivo evidence to date that abnormal dilatation of interalveolar vessels may, per se, result in a significant diffusion impairment for O 2 . Furthermore, in view of the consistently negative P-M Pa,O 2 observed during oxygen breathing, we speculate that such abnormal vascular dilatation may also have produced a significant diffusive impairment of one or more of the less soluble inert gases used in the MIGET analysis. Eur Respir J., 1995Respir J., , 8, 2015Respir J., -2021

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“…É outro estudo diagnóstico útil para a detecção de DVIP (31,32,93) . A maioria dos macroagregados de albumina possui diâmetro superior a 20 µm (maiores, portanto, que o capilar normal) e deveriam ficar impactados na microcirculação intrapulmonar, permitindo a passagem de apenas 3% a 6% dos macroagregados (93) .…”

Section: Cintilografia Pulmonar Com Maa 99m Tcunclassified

Síndrome hepatopulmonar: patogenia, diagnóstico e tratamento

Lima

Martinelli

França

2004

Arq. Gastroenterol.

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Cardiac Shunt Assessment in Children with Macroaggregated Albumin Technetium-99m

Cited by 34 publications

References 18 publications

Abnormal brain perfusion demonstrated by Tc-99m MAA total-body scan in two children with complex congenital heart disease

Abnormal brain perfusion demonstrated by Tc-99m MAA total-body scan in two children with complex congenital heart disease

Pulmonary vascular dilatation and diffusion-dependent impairment of gas exchange in liver cirrhosis

Síndrome hepatopulmonar: patogenia, diagnóstico e tratamento

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