ICU Imaging · Module 1

Imaging Foundations

Orientation, technical adequacy, projection, CT planes, contrast phases and a repeatable way to avoid interpretation errors before diagnosing disease.

~25 min2 visual lessons1 practice cases

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Reference

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Pattern

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Progression

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What you will learn

See the objectives, don’t just read them

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Objective 1
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◉

Confirm projection, patient position, rotation, inspiration and exposure before interpreting a chest radiograph.

Objective 2
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↔

Orient axial CT images correctly and understand the practical purpose of common window settings.

Objective 3
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△

Separate image quality limitations from true pathology in critically ill patients.

Objective 4
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⏱

Use prior imaging as part of the interpretation whenever available.

How to think

Use the same visual sequence every time.

See → describe → decide

1Check quality

2Find the pattern

3Assess urgency

4Compare

5Act

Projection changes appearance

PA reference vs portable AP example

Compare geometry, not pathology: these are different patients. Portable AP imaging can magnify the cardiac silhouette and is often obtained supine, changing how pleural fluid and pneumothorax appear.

PA erect reference
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Less cardiac magnification · erect positioning · standard reference projection

Portable AP example
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Expect magnification and positioning effects; do not call cardiomegaly from projection alone

Rotation

Compare medial clavicles with the spinous processes before interpreting asymmetry.

Inspiration

Low lung volume can crowd basal markings and exaggerate apparent opacity.

Exposure

Judge penetration before deciding whether central or basal opacity is real.

Visual example · Step 1
Licensed clinical image · tap to enlarge

Visual cue: inspect the image first, then connect what you see with the teaching points beside it.

Start with the image, not the diagnosis

A technically limited portable ICU study can mimic disease. The first task is deciding what the image can and cannot reliably answer.

●Confirm patient/date, modality and projection before interpreting findings.

●Portable AP and supine films magnify the heart and redistribute pleural fluid compared with an erect PA film.

●Check rotation using the clavicles/spinous processes and assess inspiration before calling asymmetry or cardiomegaly.

●Poor exposure, overlying leads and patient position should be explicitly acknowledged rather than silently ignored.

⚠ Common pitfalls · tap to reveal

•Calling cardiomegaly from an AP portable film without considering magnification.
•Calling unilateral opacity without first checking rotation and exposure.

Visual example · Step 2
Licensed clinical image · tap to enlarge

Visual cue: inspect the image first, then connect what you see with the teaching points beside it.

CT orientation and windows

For ICU CT, the learner needs reliable orientation and deliberate window switching more than detailed scanner physics.

●Axial CT is viewed as if looking from the patient's feet: the patient's right is on the viewer's left.

●Use lung and mediastinal windows for thoracic CT; brain, subdural and bone-oriented windows can reveal different abnormalities on head CT.

●Identify whether contrast was given and whether the acquisition is appropriate for the clinical question before interpreting vascular findings.

●Coronal and sagittal reconstructions help confirm extent and relationships but do not replace reviewing axial images.

Quick visual recall

If you remember only these

Quality before diagnosis

Orient CT deliberately

Know the limits of the image

Always compare with prior imaging

Now use your eyes

Practice with real cases

Interpret the image before revealing the reference interpretation.

CXR Case 024Open →

CXR · Foundation

LookInterpretReveal

References & related learning

Khan AN, et al. Reading chest radiographs in the critically ill (Part I): normal appearance, instrumentation and complications. ↗Khan AN, et al. Reading chest radiographs in the critically ill (Part II): lung pathologies. ↗Mathew R, et al. Chest radiographs of cardiac devices (Part 1): lines, tubes and non-cardiac devices. ↗Baldazzi F, et al. Chest X-ray in intensive care unit patients: thoracic devices. ↗

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