The document describes a mosaic pattern seen on chest CT scans, which appears as a patchy mixture of areas with different lung densities. This pattern is seen in conditions like asthma during expiration due to air trapping, chronic pulmonary embolism and pulmonary hypertension due to differing blood flow, and Pneumocystis pneumonia in AIDS patients where the ground glass infiltrate spares some lobular regions. Examples of each condition showing the mosaic pattern are provided.

1. 52Mosaic Pattern on Chest
Computed Tomography*

2. CLINICAL IMAGAGING
AN ATLAS OF DIFFERENTIAL DAIGNOSIS
EISENBERG
DR. Muhammad Bin Zulfiqar
PGR-FCPS III SIMS/SHL

3. • Fig C 52-1 Asthma. (A) CT scan obtained at
suspended full inspiration shows normal
findings, including a normal gradient of
attenuation. (B) Repeat study obtained at
suspended full expiration shows patchy diffuse
air trapping with typical mosaic pattern of
lung attenuation.99

4. • Fig C 52-2 Chronic pulmonary emboli and resulting
pulmonary artery hypertension. Mosaic pattern of lung
attenuation with perihilar ground-glass attenuation
and oligemic peripheral lung. Note that the caliber of
vessels in regions of higher attenuation is greater than
that in lower attenuation oligemic lung.99

5. • Fig C 52-3
Pneumocystis carinii
pneumonia in AIDS.
Mosaic pattern is
produced by ground-
glass infiltrate that
spares single lobular
and multilobular
regions.99