7.2 Pathophysiology Essentials for Radiographers

7.2 Pathophysiology Essentials for Radiographers

Quick Answer: Learn pathology the way a radiographer uses it: what it does to tissue density and patient mobility, and what you change (position, projections, kVp/mAs, grid, AEC cell). CAMRT gives high secondary weight to respiratory disease and skeletal conditions (fractures and other skeletal pathology). Medium weight covers cardiovascular, GI, and neuro concepts. Master additive vs destructive disease effects on attenuation—this is a classic technique link tested under clinical principles.

RTR.3.2 asks you to integrate pathophysiology related to procedures. You are not writing a differential diagnosis for the chart; you are deciding whether a patient with COPD needs different coaching than a patient with a suspected pneumothorax, whether osteoporotic bone needs a technique tweak, and whether a bowel obstruction series should prioritize horizontal-beam views for air-fluid levels.

How CAMRT Weights Pathology (Study Priority)

This table should drive your review time: do not spend equal hours on rare endocrine trivia and pneumonia patterns.

Respiratory Pathophysiology (High Weight)

Pneumonia

Infection produces alveolar consolidation—fluid, cells, and debris replace air. Radiographically, expect opacity in affected lobes or segments, air bronchograms in some patterns, and possible silhouette signs where borders are lost. For the technologist:

• Patients may be febrile, dyspneic, and unable to take a full inspiration—document limited inspiratory effort.
• Prefer erect PA/lateral when possible; use AP portable with careful alignment when the patient is too ill.
• Opacity is generally an additive process (more attenuation in consolidated lung).

Atelectasis

Collapse or incomplete expansion of lung reduces volume. Causes include obstruction, compression, or post-op shallow breathing. Imaging may show increased density in the collapsed region with volume-loss signs (shifted fissures, elevated hemidiaphragm, mediastinal shift toward the collapse). Technique notes: patients often cannot inspire fully; comparison with prior images matters; do not “overexpose to clean it up” without clinical reason—volume loss and density are the findings.

Pleural effusion

Fluid in the pleural space layers with gravity. Erect chest: blunting of costophrenic angles, meniscus sign as volume increases. Supine: more diffuse veil-like opacity. Lateral decubitus (affected side down, when ordered/safe) can show layering free fluid. Effusion is additive. Transfer carefully—patients may be orthopneic; do not force flat positioning if respiratory distress worsens.

Pneumothorax

Air in the pleural space allows lung to retract. Look for a visceral pleural line without peripheral lung markings (recognition detail is expanded in image-critique chapters). Tension pneumothorax is a clinical emergency (tracheal/mediastinal shift away from the affected side, hemodynamic compromise)—obtain help and do not delay care for “perfect” images. Expiration views may be used in some protocols to accentuate small pneumothoraces. Technique: avoid unnecessary delays; use appropriate acute-care workflow.

COPD (including emphysema patterns)

Chronic airflow limitation; emphysema destroys alveolar walls, increasing air space and decreasing tissue density. Imaging associations: hyperinflation, flattened diaphragms, increased AP diameter, rapid attenuation of vessels. Emphysematous lung is often treated as a destructive process for exposure thinking (less attenuating lung). Patients may be barrel-chested, use accessory muscles, and desaturate with exertion—short, clear breathing instructions; allow recovery between attempts.

Pulmonary embolism (concepts)

PE is obstruction of pulmonary arteries (often thromboembolic). Chest radiography is frequently normal or nonspecific; definitive imaging is typically CT pulmonary angiography or nuclear medicine V/Q in appropriate pathways. Your role: recognize why the chest x-ray may still be ordered (rule out mimics, baseline), prioritize safe transport/monitoring for unstable patients, and understand that “normal chest x-ray does not exclude PE.”

Skeletal Pathophysiology (High Weight)

Fracture classification overview

You will not replace the radiologist’s report, but you must handle injured patients and produce diagnostic projections. Useful descriptors:

Golden rules: immobilize as found when unstable; obtain at least two projections 90° apart when feasible; include adjacent joints on long-bone trauma per protocol; never force a position that risks neurovascular compromise—adapt with crosstable/horizontal beam techniques.

Other skeletal conditions

Osteoarthritis (OA) — degenerative joint disease: joint-space narrowing, osteophytes, subchondral sclerosis. Patients may have limited ROM; do not force weight-bearing angles they cannot achieve—modify and document. Weight-bearing views may be protocol-critical for knees.

Osteoporosis — reduced bone mineral density; increased fracture risk (vertebral compression, hip, wrist). Radiographically, bones appear more lucent (destructive relative to normal bone attenuation). Technique: lower exposure factors may be appropriate; AEC still needs correct cell selection and centering. Handle hips and spines with fall-prevention mindset.

Scoliosis — lateral curvature ± rotation of the spine. Imaging often uses dedicated scoliosis series with careful centering, consistent SID, and gonadal shielding policies per site/protocol and exam appropriateness. Positioning must keep the entire curve on the image receptors as ordered; mark sides clearly.

Other patterns to recognize at working level: osteomyelitis (infection—may be additive soft-tissue/bone changes over time), metastatic bone disease (lytic destructive vs blastic additive deposits), rheumatoid arthritis (different joint distribution than OA). Depth of description matters less than knowing lytic ≈ destructive and blastic/sclerotic ≈ additive for technique intuition.

Medium-Weight Systems (Brief but Testable)

Cardiovascular

Cardiomegaly, congestive patterns (redistribution, interstitial/alveolar edema, pleural effusions), aortic aneurysm/ dissection pathways (often CT), and line/tube placement checks on portable chests. For technique: fluid-overloaded lungs are more attenuating; patients may be orthopneic—erect or semi-erect preferred when possible. Pacemakers/ICDs: know not to raise the ipsilateral arm excessively in the early post-implant period per clinical orders.

Gastrointestinal

Bowel obstruction (dilated loops, air-fluid levels on horizontal-beam images), free intraperitoneal air (erect chest or left lateral decubitus abdomen), free fluid, and post-surgical anatomy. Additive soft-tissue masses vs gas patterns change appearance more than simple “kVp charts.” Contrast studies appear in later chapters—here, know why horizontal beam demonstrates levels and why erect chest is often part of an acute abdominal series for free air under the diaphragm.

Neurological

Stroke pathways increasingly bypass plain skull films; cervical spine trauma clearance is protocol-driven (often CT). For general radiography: C-spine immobilization until cleared; horizontal-beam lateral when indicated; skull series are less common but still require precise planes and baselines. Seizure or decreased LOC patients need airway awareness and rapid assistance pathways.

Additive vs Destructive Disease and Exposure Adjustment

This is the highest-yield technique bridge in RTR.3.2.

Additive examples: pneumonia, pleural effusion, pulmonary edema, ascites, soft-tissue edema, osteoblastic metastases, Paget disease (often thicker denser bone), contrast-filled structures.

Destructive examples: osteoporosis, osteolytic metastases, emphysema (lung), bowel gas overdistention patterns (localized lucency), necrosis with tissue loss.

Practical adjustment principles (not magic numbers)

1. Use your department technique chart and AEC correctly first—pathology adjustment is refinement, not random guessing.
2. Large additive processes (large effusion, dense consolidation, ascites) commonly need more exposure; large destructive processes (severe osteoporosis, marked emphysema) commonly need less.
3. Changing kVp affects both penetration and contrast; changing mAs mainly affects quantity/receptor exposure. Know which lever your chart prefers for the exam room.
4. Never underexpose a critical trauma series just to “protect” the detector—non-diagnostic images create repeats and more dose.
5. Document when pathology or body habitus forced a deviation from standard factors.

Linking Pathology to Procedure Choices (Exam Style)

• Suspected free air → include erect chest or left lateral decubitus abdomen as protocol directs.
• Suspected small pneumothorax → consider expiration or dedicated views per protocol; escalate if tension physiology.
• Hip fracture in elderly osteoporotic patient → minimize moves; horizontal-beam lateral; gentle handling; possible factor reduction for osteopenia.
• Scoliosis follow-up → consistent positioning and centering so curves are comparable over time.
• CHF portable chest → semi-erect if possible; watch for lines/tubes; expect additive lung water.

CAMRT Application Focus

RTR.3.2 items are usually application: given a condition, what do you do? Pure recall of a rare eponym is less likely than recognizing that emphysema is destructive, that effusion layers with gravity, or that a spiral fracture still needs orthogonal imaging without rough rotation of the limb.

Self-check:

• Is pleural effusion additive or destructive? Additive.
• Why might technique decrease in severe osteoporosis? Less attenuating bone.
• Does a normal chest x-ray exclude PE? No.
• Minimum projections for most fractures? Two at ~90° when feasible, plus joints as required.

Pathophysiology for radiographers is applied tissue physics plus patient-centered positioning. If you can name the disease, predict the density change, and choose a safer, more diagnostic projection set, you are studying at CAMRT depth.