MyPACS.net: Radiology Teaching Files > Case 253732

never visited MOSAIC ATTENUATION
Contributed by: Conrad Pun, Resident, Henry Ford Hospital, Michigan, USA.
Patient: 56 year old female
History: Shortness of breath and restrictive/obstructive pattern on pulmonary function tests.
Images:[small]larger

Fig. 1: HRCT at full inspiration

Fig. 2: HRCT at end expiration
Findings:

Mosaic pattern of high and low attenuation areas with relatively decreased number and caliber of vessels in the hyperlucent areas on full-inspiratory HRCT images.

Air trapping within persistent low attenuation areas on end-expiratory HRCT images.

Diagnosis: Small airways disease, clinical diagnosis has not been established.
Discussion:

Mosaic attenuation of lung on CT can be grouped into three categories:

Small airways disease: Regional air trapping and hypoxic vasoconstriction will appear as decreased size and number of vessels and decreased attenuation in the affected regions in comparison to areas of normally ventilated lung. Decreased attenuation and/or increased volume of affected areas will persist on end-expiratory images. The differential includes asthma, bronchiolitis obliterans, cystic fibrosis.

Small vessel disease: Also known as “mosaic perfusion”, obliteration of small vessels gives the affected areas a decreased attenuation in comparison to normally perfused lung. There will be no air trapping on end-expiratory images. The differential includes chronic pulmonary embolism.

Infiltrative disease: Patchy infiltration of the interstitium and/or partial filling of airspaces with fluid, cells, or fibrosis will increase attenuation in affected areas. The vessel size will be uniform and there will be no air trapping. The differential includes Pneumocystis carinii pneumonia, eosinophillic pneumonia, hypersensitivity pneumonia.

References: Stern EJ, et al. CT Mosaic Pattern of Lung attenuation: Distinguishing Different Causes. AJR 1995;165:813-816
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Additional Details:

Case Number: 253732Last Updated: 12-11-2003
Anatomy: Lung   Pathology: Other
Modality: CTExam Date: Access Level: Readable by all users
Keywords: lung mosaic ventilation perfusion attenuation

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