aspiration pneumonia imaging

8/3/2019 Aspiration Pneumonia Imaging

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Aspiration Pneumonia Imaging

Contributor Information and Disclosures

Author

Jaw Lee, MD Staff Physician, Department of Emergency Medicine, King-DrewMedical Center

Jaw Lee, MD is a member of the following medical societies:American Collegeof Emergency Physicians

Disclosure: Nothing to disclose.

Specialty Editor Board

Judith K Amorosa, MD, FACR Clinical Professor and Program Director,Department of Radiology, University of Medicine and Dentistry of New Jersey,Robert Wood Johnson Medical School; Consulting Staff, Department of

Radiology, Robert Wood Johnson University Hospital

Judith K Amorosa, MD, FACR is a member of the following medicalsocieties:American College of Radiology,American Roentgen RaySociety,Association of University Radiologists, Radiological Society of NorthAmerica, and Society of Thoracic Radiology


Bernard D Coombs, MB, ChB, PhD Consulting Staff, Department ofSpecialist Rehabilitation Services, Hutt Valley District Health Board, NewZealand


Eric J Stern, MD Professor of Radiology, Adjunct Professor of Medicine,Adjunct Professor of Medical Education and Biomedical Informatics, AdjunctProfessor of Global Health, University of Washington School of Medicine

Eric J Stern, MD is a member of the following medical societies: AmericanRoentgen Ray Society,Association of University Radiologists, European Societyof Radiology, Radiological Society of North America, and Society of ThoracicRadiology


Robert M Krasny, MD Resolution Imaging Medical Corporation

Robert M Krasny, MD is a member of the following medical societies: AmericanRoentgen Ray Societyand Radiological Society of North America



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Chief Editor

Eugene C Lin, MD Consulting Radiologist, Virginia Mason Medical Center;Clinical Assistant Professor of Radiology, University of Washington School ofMedicine

Eugene C Lin, MD is a member of the following medical societies:American

College of Nuclear Medicine,American College of Radiology, RadiologicalSociety of North America, and Society of Nuclear Medicine


Overview

Aspiration is defined as entry of a foreign substance, solid or liquid, into therespiratory tract or inhalation of fumes and vapors. Aspiration pneumonia is aninfectious process caused by aspirated oropharyngeal flora. Aspiration

pneumonitis, which is caused by a direct chemical insult due to the aspiratedmaterial, is technically a different entity, but is often referred to as aspirationpneumonia. (See the images below.)

Aspiration pneumonia. A 29-year-old man with history ofcerebral palsy and seizure disorder was brought to the emergency department because hehad decreased responsiveness for 3 days. The patient was in respiratory distress on arrivaland was immediately intubated. His vital signs were as follows: temperature, 92.9F; bloodpressure, 85 mm Hg/23 mm Hg, respirations, 25 per minute; and heart rate, 89 per minute.Chest radiograph revealed an endotracheal tube far above the carina, bilateral opacities,

and a well-defined right upper lobe consolidation.Aspiration pneumonia. CT scan through the lower-lobe bronchi demonstrates a metallicobject in the left lower-lobe bronchus. The patient had aspirated a filling, which had fallenout of one of his teeth. The patient underwent bronchoscopy, and the foreign body wasremoved. The patient was treated with antibiotics for the pneumonia, which eventuallyresolved. Incidentally, a small pleural effusion on the right side was due to minimalcongestive heart failure (CHF).


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lobes. Alternatively, the radiographic abnormalities may be more extensivelydistributed. (See the images below.)

Aspiration pneumonia. A 29-year-old man with history ofcerebral palsy and seizure disorder was brought to the emergency department because hehad decreased responsiveness for 3 days. The patient was in respiratory distress on arrivaland was immediately intubated. His vital signs were as follows: temperature, 92.9F; bloodpressure, 85 mm Hg/23 mm Hg, respirations, 25 per minute; and heart rate, 89 per minute.Chest radiograph revealed an endotracheal tube far above the carina, bilateral opacities,

and a well-defined right upper lobe consolidation.Aspiration pneumonia. Close-up image of the right upper lobe shows lung parenchymalconsolidation. The clinical information and imaging data indicate aspiration pneumonia. Theaspirate was cultured and demonstrated multiple organisms consistent with aspiration

pneumonia. Aspiration pneumonia. An 84-year-old man ingenerally good health had fever and cough. Posteroanterior radiograph demonstrates a left


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Aspiration pneumonia. CT scan through the lower lobes ona pulmonary window demonstrates a round opacity in the left lower lobe, which was

believed to represent a neoplasm. Aspiration pneumonia.CT scan through the lower-lobe bronchi demonstrates a metallic object in the left lower-lobe bronchus. The patient had aspirated a filling, which had fallen out of one of his teeth.The patient underwent bronchoscopy, and the foreign body was removed. The patient wastreated with antibiotics for the pneumonia, which eventually resolved. Incidentally, a smallpleural effusion on the right side was due to minimal congestive heart failure (CHF).CT or ultrasonographic guidance is useful for localization of abnormalities forbiopsy or aspiration/drainage.

Complications from aspiration pneumonia (eg, abscess formation, lungnecrosis, empyema) are well depicted on CT scans. Long-term complications,such as obliterative bronchiolitis, are diagnosed best with high-resolution CT(HRCT).

HRCT findings in patients with exogenous lipoid pneumonia may include air-space consolidations with fatty or nonspecific but low attenuation values, areasof ground-glass opacities, septal lines, and centrilobular interstitial thickening.[8, 9,10, 11] HRCT may also demonstrate a crazy-paving pattern, either isolated orsurrounding a pulmonary consolidation.

Multidetector CT (MDCT) has proved to be effective in the evaluation ofpneumonia from aspirated foreign bodies or liquid [12] In patients with suspectedforeign body aspiration, virtual bronchoscopy, in conjunction with MDCT, candelineate the precise location of an obstructing foreign body, thereby facilitatingconventional bronchoscopy; it can also obviate bronchoscopy by providing analternative diagnosis.[13]

CT scanning also can define anatomic abnormalities in the head, neck, andchest areas. These findings may be helpful in detailing the underlying causes ofaspiration such as fistulas or tumors in the pharynx, larynx, or esophagus. CTscans may also reveal esophageal strictures, including achalasia.

Degree of confidence


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CT scanning is considered to provide a higher degree of confidence than asingle AP, PA, or lateral plain radiograph. However, some of the same diseasesthat mimic radiographic findings of aspiration also can confound the diagnosticinterpretation of CT scans.

Magnetic Resonance Imaging

Few large studies of MRI dedicated to aspiration diseases have beenperformed. However, results of published case studies appear to confirm theaccuracy of MRI for imaging such conditions as acute inflammation, granuloma,and fibrosis. MRI performs well in defining the nature of the aspirate and thebody's reactions to the aspirate. Some authors have found that MRI is superiorto CT scanning in the diagnosis of lipoid aspirations.

False positives/negatives

The sensitivity of MRI is expected to be high, with few false-negative results,although, as with CT scanning, false-positive results due to pathologicprocesses with features mimicking those of aspiration pneumonia should

always be considered.

Nuclear Imaging

A radionuclide salivagram can demonstrate the aspiration ofsaliva.[14]Salivagrams can document salivary aspiration as the source ofrecurrent pneumonia, often in children with neurologic impairment.[15]

Exogenous lipoid pneumonia mimicking malignancy on positron emissiontomography (PET) scan has been reported.[16]

aspiration pneumonia imaging

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