The Current and Continuing Important Role of Ventilation-Perfusion Scintigraphy in Evaluating Patients With Suspected Pulmonary Embolism

Freeman, Leonărd M.; Stein, Evan G.; Sprayregen, Seymour; Chamarthy, Murthy R.; Haramati, Linda B.

doi:10.1053/j.semnuclmed.2008.07.001

Cited by 39 publications

(17 citation statements)

References 61 publications

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“…Similarly, images resulting from 129 Xe within the RBCs should reveal regions of restricted capillary blood flow caused by pulmonary embolism. Thus, in combination with high-resolution ventilation images, dissolved HP 129 Xe MRI could yield data akin to that obtained from scintigraphic ventilation/perfusion imaging [49], but with superior temporal resolution and without the need for ionizing radiation.…”

Section: Resultsmentioning

confidence: 99%

Hyperpolarized 129Xe MR Imaging of Alveolar Gas Uptake in Humans

et al. 2010

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BackgroundOne of the central physiological functions of the lungs is to transfer inhaled gases from the alveoli to pulmonary capillary blood. However, current measures of alveolar gas uptake provide only global information and thus lack the sensitivity and specificity needed to account for regional variations in gas exchange.Methods and Principal FindingsHere we exploit the solubility, high magnetic resonance (MR) signal intensity, and large chemical shift of hyperpolarized (HP) 129Xe to probe the regional uptake of alveolar gases by directly imaging HP 129Xe dissolved in the gas exchange tissues and pulmonary capillary blood of human subjects. The resulting single breath-hold, three-dimensional MR images are optimized using millisecond repetition times and high flip angle radio-frequency pulses, because the dissolved HP 129Xe magnetization is rapidly replenished by diffusive exchange with alveolar 129Xe. The dissolved HP 129Xe MR images display significant, directional heterogeneity, with increased signal intensity observed from the gravity-dependent portions of the lungs.ConclusionsThe features observed in dissolved-phase 129Xe MR images are consistent with gravity-dependent lung deformation, which produces increased ventilation, reduced alveolar size (i.e., higher surface-to-volume ratios), higher tissue densities, and increased perfusion in the dependent portions of the lungs. Thus, these results suggest that dissolved HP 129Xe imaging reports on pulmonary function at a fundamental level.

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Section: Resultsmentioning

confidence: 99%

Hyperpolarized 129Xe MR Imaging of Alveolar Gas Uptake in Humans

et al. 2010

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“…In an additional 0.3%, DVT had developed by the 3-mo follow-up (37). In a Montefiore study, PE was excluded in patients in the emergency department if they had a negative or very low probability V/Q result and normal or near-normal chest radiography findings (38). In 1.1% of such patients, PE or DVT was shown at the 3-mo follow-up.…”

Section: Outcome Studiesmentioning

confidence: 99%

“…Pulmonary embolism was considered absent by SPECT V/Q imaging if there were no mismatched perfusion defects (16). Technegas was used for ventilation scintigraphy Two publications (37,38) have shown that planar V/Q scans exclude PE with no less of a negative predictive value than SPECT scans, although Anderson et al (37) used findings in addition to V/Q scans to exclude PE. Pulmonary embolism was excluded by normal planar V/Q findings or nondiagnostic V/Q findings with negative leg ultrasonography results plus either an ''unlikely'' Wells' score of less than 4.5 or a negative D-dimer result (37).…”

Section: Outcome Studiesmentioning

confidence: 99%

SPECT in Acute Pulmonary Embolism

Stein¹,

Freeman²,

Sostman³

et al. 2009

J Nucl Med

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The purpose of this review was to evaluate the accuracy of SPECT in acute pulmonary embolism. Sparse data are available on the accuracy of SPECT based on an objective reference test. Several investigations were reported in which the reference standard for the diagnosis of pulmonary embolism was based in part on the results of SPECT or planar ventilation-perfusion (V/Q) imaging. The sensitivity of SPECT in all but one investigation was at least 90%, and specificity also was generally at least 90%. The sensitivity of SPECT in 4 of 5 investigations was higher than that of planar V/Q imaging. The specificity of SPECT was generally higher, equal, or only somewhat lower than that of planar V/Q imaging. Most investigators reported nondiagnostic SPECT V/Q scans in no more than 3% of cases. Methods of obtaining SPECT images, methods of obtaining planar V/Q images, and the criteria for interpretation varied. The general impression is that SPECT is more advantageous than planar V/Q imaging.

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“…25,42–44 Ventilation-perfusion scanning remains a valuable diagnostic modality in patients with contrast allergies, renal insufficiency, excessive obesity, and claustrophobia. 45 Unfortunately, V/Q scans are frequently indeterminate such that further diagnostic evaluation is often required. Indeterminate V/Q scans can be minimized by selecting patients who are young and have normal chest radiographic findings.…”

Section: Resultsmentioning

confidence: 99%

Radiation Dose From Medical Imaging: A Primer for Emergency Physicians

Jones¹,

Mills²,

Mogensen³

et al. 2012

WestJEM

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IntroductionMedical imaging now accounts for most of the US population's exposure to ionizing radiation. A substantial proportion of this medical imaging is ordered in the emergency setting. We aim to provide a general overview of radiation dose from medical imaging with a focus on computed tomography, as well as a literature review of recent efforts to decrease unnecessary radiation exposure to patients in the emergency department setting.MethodsWe conducted a literature review through calendar year 2010 for all published articles pertaining to the emergency department and radiation exposure.ResultsThe benefits of imaging usually outweigh the risks of eventual radiation-induced cancer in most clinical scenarios encountered by emergency physicians. However, our literature review identified 3 specific clinical situations in the general adult population in which the lifetime risks of cancer may outweigh the benefits to the patient: rule out pulmonary embolism, flank pain, and recurrent abdominal pain in inflammatory bowel disease. For these specific clinical scenarios, a physician-patient discussion about such risks and benefits may be warranted.ConclusionEmergency physicians, now at the front line of patients' exposure to ionizing radiation, should have a general understanding of the magnitude of radiation dose from advanced medical imaging procedures and their associated risks. Future areas of research should include the development of protocols and guidelines that limit unnecessary patient radiation exposure.

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The Current and Continuing Important Role of Ventilation-Perfusion Scintigraphy in Evaluating Patients With Suspected Pulmonary Embolism

Cited by 39 publications

References 61 publications

Hyperpolarized 129Xe MR Imaging of Alveolar Gas Uptake in Humans

Hyperpolarized 129Xe MR Imaging of Alveolar Gas Uptake in Humans

SPECT in Acute Pulmonary Embolism

Radiation Dose From Medical Imaging: A Primer for Emergency Physicians

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