| Organ
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Disease
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Description
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CT
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MRI
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SONO
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| Gastrointestinal system
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Dysphagia
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- Barium swallow/esophagography
- Oesophageal stricture
- Peptic strictures that appear as smooth, tapered narrowing in the distal esophagus
- Esophageal dilatation
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| Intestinal pseudo-obstruction
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- dilated bowel loops with or without the presence of fluid levels
- Erect chest radiographs for perforation evaluating
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- dilated bowel loops with or without the presence of fluid levels
- a distinct transition point where bowel calibre changes from normal to abnormal
- dilated bowel loops proximal to the transition point
- small bowel >3.5 cm
- large bowel >5 cm
- collapsed or normal calibre bowel distal to the transitional point
- bowel wall thickening
- Obstruction:
- pneumoperitoneum indicating perforation
- bowel ischaemia
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| Hepatitis
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- Hepatic granulomas
- Nonspecific, ranging from normal to hepatomegaly and cirrhosis.
- Discrete, sharply defined nodular lesions within the liver
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- nodules ranging around 0.5-4.5 cm in diameter
- T2: nonspecific, increased periportal oedema 4
- MRCP: primary sclerosing cholangitis (PSC) should be excluded
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| Acute pancreatitis
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Abnormalities that may be seen in the pancreas include:
- typical findings
- focal or diffuse parenchymal enlargement
- changes in density because of oedema
- indistinct pancreatic margins owing to inflammation
- surrounding retroperitoneal fat stranding
- liquefactive necrosis of pancreatic parenchyma
- lack of parenchymal enhancement
- often multifocal
- infected necrosis
- difficult to distinguish from aseptic liquefactive necrosis
- the presence of gas is helpful
- FNA helpful
- abscess formation
- circumscribed fluid collection
- little or no necrotic tissues (thus distinguishing it from infected necrosis)
- haemorrhage
- high-attenuation fluid in the retroperitoneum or peripancreatic tissues
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Contrast-enhanced MR is equivalent to CT in the assessment of pancreatitis.
Abnormalities that may be seen in the pancreas include:
- typical findings
- focal or diffuse parenchymal enlargement
- changes in density because of oedema
- indistinct pancreatic margins owing to inflammation
- surrounding retroperitoneal fat stranding
- liquefactive necrosis of pancreatic parenchyma
- lack of parenchymal enhancement
- often multifocal
- infected necrosis
- difficult to distinguish from aseptic liquefactive necrosis
- the presence of gas is helpful
- FNA helpful
- abscess formation
- circumscribed fluid collection
- little or no necrotic tissues (thus distinguishing it from infected necrosis)
- haemorrhage
- high-attenuation fluid in the retroperitoneum or peripancreatic tissues
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- to identify gallstones as a possible cause
- diagnosis of vascular complications, e.g. thrombosis
- identify areas of necrosis which appear as hypoechoic regions
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| Aotpsplenectomy
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If heavily calcified, the splenic remnant may be visible in the left upper quadrant.
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CT easily identifies the abnormally small and irregular splenic remnant, which is usually calcified.
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Ultrasound will either not be able to demonstrate a spleen at all, or identify a small irregular and shadowing nodule in the splenic bed.
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| Enteritis
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The main feature of enteritis is small bowel wall thickening. Low density submucosal edema can usually be differentiated from higher density mural haemorrhage or infiltration. Dilatation or strictures may or may not be present, the later if chronic.
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| Mesenteric vasculitis
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- The comb sign refers to the hypervascular appearance of the mesentery
- This forms linear densities on the mesenteric side of the affected segments of small bowel, which give the appearance of the teeth of a comb.
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- The comb sign refers to the hypervascular appearance of the mesentery
- This forms linear densities on the mesenteric side of the affected segments of small bowel, which give the appearance of the teeth of a comb.
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| Acute cholecystitis
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- gallbladder distension
- gallbladder wall thickening
- mural or mucosal hyperenhancement
- pericholecystic fluid and inflammatory fat stranding
- enhancement of the adjacent liver parenchyma due to reactive hyperaemia
- tensile gallbladder fundus sign 7
- fundus bulging the anterior abdominal wall
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MR cholangiopancreatography (MRCP) may show an impacted stone in the gallbladder neck or cystic duct as a rounded filling defect.
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- gallbladder wall thickening (>3 mm) and pericholecystic fluid
- Positive Murphy sign
- gallbladder distension
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| Pulmonary involvement
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Pleural effusion
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- A lateral decubitus film can visualise small amounts of fluid layering against the dependent parietal pleura.
- PA and AP CXR:
- blunting of the costophrenic angle
- blunting of the cardiophrenic angle
- fluid within the horizontal or oblique fissures
- mediastinal shifts with large amounts of fluid
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- May be associated with thickening of the pleura
- Fluid density
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echo-free space between the visceral and parietal pleura
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| Acute pneumonitis
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- A rare and fulminant form of diffuse lung injury that generally occurs in previously healthy individuals and has a rapid onset with fever, cough, and shortness of breath.
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| Pulmonary hemorrhage
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- Pulmonary alveolar hemorrhage:
- A rare complication
- Acutely ill patients with hemoptysis, fever, cough, and hypoxemia.
- Blood loss can be extensive.
- Associated with high mortality rates of 70%–90%
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| Pulmonary hypertension
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| Pulmonary emboli
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- Fleishner sign: enlarged pulmonary artery (20%)
- Hampton hump: peripheral wedge of airspace opacity and implies lung infarction (20%)
- Westermark sign: regional oligaemia and highest positive predictive value (10%)
- pleural effusion (35%)
- knuckle sign 11
- Palla's sign17: enlarged right descending pulmonary artery
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- filling defects within the pulmonary vasculature with acute pulmonary emboli
- vascular CT signs include
- direct pulmonary artery signs
- complete obstruction
- partial obstruction
- eccentric thrombus
- calcified thrombus - calcific pulmonary emboli
- pulmonary arterial bands/pulmonary arterial webs 1,4-5
- post stenotic dilatation
- signs related to pulmonary hypertension
- enlargement of main pulmonary arteries
- the peripheral pulmonary arteries in affected segments may be narrowed ref required
- pulmonary arterial calcification
- tortuous pulmonary vessels
- right ventricular enlargement/hypertrophy
- signs of systemic collateral supply
- enlargement of bronchial and nonbronchial systemic arteries
- Signs of chronic obstruction: webs or bands, intimal irregularities 3/ abrupt narrowing or complete obstruction of the pulmonary arteries 3 / “pouching defects” which are defined as chronic thromboembolism organised in a concave shape that “points” toward the vessel lumen
- parenchymal signs (often non-specific on their own):
- scars
- mosaic perfusion pattern
- focal ground-glass opacities
- bronchial anomalies
- The central filling defect from the thrombus is surrounded by a thin rim of contrast, appearing like the popular sweet, the polo mint
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| Shrinking lung syndrome
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- small but clear lungs with diaphragmatic elevation
- basal atelectasis
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- reduced lung volumes with diaphragmatic elevation +/- occasional basal atelectasis but without any major parenchymal lung or pleural disease
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| Cardiac involvement
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Cardiomegaly
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| Mitral stenosis
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- cardiomegaly
- double right heart border (enlarged left atrium and normal right atrium)
- prominent left atrial appendage
- splaying of the subcarinal angle (>120 degrees)
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valve thickening or leaflet fixation
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- mitral leaflet thickening
- reduced diastolic opening
- abnormal valve motion toward the left ventricular outflow tract
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| Mitral regurgitation
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frontal projection
- left atrial enlargement
- convexity or straightening of the left atrial appendage just below the main pulmonary artery (along left heart border)
- double density sign: the right side of the enlarged left atrium pushes into the adjacent lung and creates an addition contour superimposed over the right heart
- elevation of the left main bronchus and splaying of the carina
- upper zone venous enlargement due to pulmonary venous hypertension
- left ventricular enlargement is also eventually present due to volume overload
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| Acute pericarditis
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enhancement of the thickened pericardium generally indicates inflammation
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The normal pericardial thickness is considered 2 mm while a thickness of over 4 mm suggests a pericarditis
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| Pericardial effuson
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- globular enlargement of the cardiac shadow giving a water bottle configuration
- Lateral CXR may show a vertical opaque line (pericardial fluid) separating a vertical lucent line directly behind sternum (epicardial fat) anteriorly from a similar lucent vertical lucent line (pericardial fat) posteriorly; this is known as the Oreo cookie sign
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Fluid density material is seen surrounding the heart
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Fluid density material is seen surrounding the heart
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Echocardiography is the method of choice to confirm the diagnosis, estimate the volume of fluid and most importantly assess the haemodynamic impact of the effusion
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| Myocarditis
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- regional or global wall motion abnormalities are common, but nonspecific (biventricular wall motion abnormality, however, is the main predictor of death or transplantation)
- pericardial effusion is reported in ~45% (range 32-57%) of patients with myocarditis
- regional vasodilatation and increased blood volume due to the inflammation in myocarditis causes early postcontrast enhancement
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| Coronary artery disease
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- coronary CT angiography (cCTA)
- can show the amount of stenosis
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| Neurological involvement
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Cognitive dysfunction
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- The mental status of SLE patients can be temporarily affected by multiple, transient metabolic and systemic processes
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| Stroke
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- Early sign: a hyperdense segment of a vessel, representing direct visualisation of the intravascular thrombus / embolus and as such is visible immediately
- Early hyperacute: loss of grey-white matter differentiation, and hypoattenuation of deep nuclei
- cortical hypodensity with associated parenchymal swelling with resultant gyral effacement
- elevation of the attenuation of the cortex. This is known as the CT fogging phenomenon
- a region of low density with negative mass effect. Cortical mineralisation can also sometimes be seen appearing hyperdense.
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- the affected parenchyma appears normal on other sequences, although changes in flow will be detected (occlusion on MRA) and the thromboembolism may be detected (e.g. on SWI). Slow or stagnant flow in vessels may also be detected as a loss of normal flow void and high signal
- after 6 hours, high T2 signal will be detected
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| Neuropathies
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- Optic neuritis:
- Typically findings are most easily identified in the retrobulbar intra-orbital segment of the optic nerve, which appears swollen, with high T2 signal. High T2 signal persists and may be permanent; chronically the nerve will appear atrophied rather than swollen. Contrast enhancement of the nerve, best seen with fat-suppressed T1 coronal images, is seen in >90% of patients if scanned within 20 days of visual loss
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Autoimmune encephalitis
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mesial temporal lobes and limbic systems, typically manifested by cortical thickening and increased T2/FLAIR signal intensity of these regions. Bilateral involvement is most common (60%), although often asymmetric
Patchy areas of enhancement
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Raynaud phenomen
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contrast-enhanced MR angiography may also reveal characteristic narrowing and tapering of digital vessels
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Doppler sonography:
flow volume and vessel size irregularities
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Myositis
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Intramuscular oedema (increased high T2/STIR signal)
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| Musculoskeletal involvement
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Arthritis
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- Mostly symmetrical and non-erosive
- Arthralgias
- Effusions
- Decreased range of motion of both small and large joints
- Morning stiffness
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| Osteonecrosis (Avascular necrosis)
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- Most common in the femoral head
- Can involve humeral head, tibial plateau, and scaphoid navicular
- Usually bilateral and is often asymptomatic
- Glucocorticoids treatment is associated with the greatest risk of developing the disease
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| Subcutaneous nodules
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- In association with active disease
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| Osteoporosis
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