Radiology of Selected Diseases (Part 2) PDF

Radiology of Selected Diseases (Part 2)  Table of contents 01 Airway Diseases. 02 Interventional Radiology. Airway diseases 1-Bronchiectasis: -Irreversible abnormal dilatation of the bronchial tree. -It has a variety of underlyingcauses, with a common etiology of chronic...

Radiology of Selected Diseases (Part 2)  Table of contents 01 Airway Diseases. 02 Interventional Radiology. Airway diseases 1-Bronchiectasis: -Irreversible abnormal dilatation of the bronchial tree. -It has a variety of underlyingcauses, with a common etiology of chronic inflammation. -High resolutionCT is the most accurate modality for diagnosis. Airway diseases -Subtypes: According to macroscopic morphology, also represent a spectrum of severity : Cylindrical bronchiectasis: o Bronchi have a uniform caliber, do not taper and have parallel walls (tram track sign and signet ring sign) o Commonest form. Varicose bronchiectasis: o Relatively uncommon. o Beaded appearances where dilated bronchi have interspersedsites of relative narrowing. Cystic bronchiectasis: o Severe form with cyst-like bronchi that extend to the pleural surface. o Air-fluid levels are commonly present. Airway diseases Plain radiograph: -Chest x-rays are usually abnormal but are inadequate in the diagnosis or quantification of bronchiectasis. -Tram-track opacities are seen in cylindrical Bronchiectasis. -Air-fluid levels may be seen in cystic bronchiectasis. -There appears to be an increase in bronchovascular markings, and bronchi seen end on may appear as ring shadows. -Pulmonaryvasculature appears ill-defined, thought to represent peribronchovascular fibrosis. Airway diseases CT: A number of features are helpful in diagnosing bronchiectasis : *Bronchus visualized within 1 cm of pleural surface: o Especially true of lung adjacent to costal pleura. o Most helpful sign for early cylindrical change. *Lack of tapering. *Increased bronchoarterial ratio: o Diameter of a bronchus should measure approximately 0.65 -1.0 times that of the adjacent pulmonary artery branch. o Greater than 1.5 indicates bronchiectasis Airway diseases *A number of ancillary findings are also recognized: Bronchial wall thickening: normally wall of bronchus should be less than half the width of the accompanying pulmonary artery branch. Mucoid impaction. Air-trapping and mosaic perfusion. *Signs described on CT include: Tram-track sign. Signet ring sign. String of pearls sign. Cluster of grapes sign. Airway diseases Airway diseases 2- Emphysema: -Abnormal permanent enlargement of the airspaces distal to the terminal bronchioles accompanied by destruction of the alveolar wall and without obvious fibrosis. -Emphysema is one of the entities grouped as chronic obstructive pulmonary disease. -Emphysema is best evaluated on CT. Subtypes: Centrilobular emphysema: 1 It is the most frequent type. 2 Affects the proximal respiratory bronchioles. 3 More in the upper zones. 4 Strongly associated with smoking in a dose-dependent way. Panlobular emphysema: 1 It affects the entire secondary pulmonary lobule. 2 More in the lower zones, matching areas of maximal blood flow. Paraseptal emphysema: 1 Affects the peripheral parts of the secondary pulmonary lobule. 2 Usually located adjacent to the pleural surfaces (including pleural fissures). 3 Associated with smoking, and can lead to the formation of subpleural bullae and spontaneous pneumothorax. Airway diseases Plain radiograph: *Exceptin the case of very advanced disease with bulla formation,chest radiography does not image emphysemadirectly, but suspect the diagnosis. Associated features : Hyperinflation: Vascular changes 1 Flattened hemidiaphragm(s): most 1 Paucity of blood vessels, often reliable sign. distorted. 2 Increased and usually irregular 2 Pulmonary arterial hypertension. radiolucency of the lungs. Pruning of peripheral vessels. 3 Increased retrosternal airspace. Increased caliber of central Increased anteroposterior diameter of the arteries. chest. Right ventricular enlargement. 4 Widely spaced ribs. 5 Sternal bowing. 6 Tenting of the diaphragm. Airway diseases  Airway diseases CT: *Able to discriminate between centrilobular, panlobular, and paraseptal emphysema. 1) Centrilobular emphysema: 1 Predominantlyin the upper zones of each lobe (i.e. apical and posterior segmentsof the upper lobes, and superiorsegment of the lower lobes). 2 Has a patchy distribution. 3 It appears as focal lucencies (emphysematous spaces) which measure up to 1 cm in diameter,located centrally within the secondary pulmonary lobule, often with a central or peripheral dot representing the central bronchovascular bundle. Airway diseases 2) Panlobular emphysema: 1 Predominantly located in the lower lobes. 2 Has a uniform distributionacross parts of the secondary pulmonarylobule. 3) Paraseptal emphysema: 1 Located adjacent to the pleura and septal lines. 2 Peripheral distribution within the secondary pulmonarylobule. 3 The affected lobules are almost always subpleural and demonstrate small focal lucencies up to 10 mm in size. *Any lucency >10 mm should be referred to as subpleural blebs/bullae (synonymous). *In all three subtypes, the emphysematous spaces are not bounded by any visible wall Airway diseases Airway diseases 3-Chronic Obstructive Pulmonary Disease (COPD) -Spectrum of obstructive airway diseases. -It includes two key components: 1- chronic bronchitis-small airways disease. 2-emphysema. Clinical phenotypes: emphysema predominant airways predominant o small airways predominant o large airways predominant mixed  Airway diseases -Plain radiograph: *Findings are non-specific: 1 Increased bronchovascular markings. 2 Cardiomegaly. 3-Emphysema manifests as lung hyperinflation with flattened hemidiaphragms, a small heart, and possible bullous changes. Airway diseases CT: Chronic bronchitis 1-Bronchial wall thickening may be seen in addition to enlarged vessels. 2-Repeated inflammation can lead to scarring with bronchovascular irregularity and fibrosis. Emphysema Interventional Radiology  Introduction -Angiography as a radiology procedure developed in the 1920s. -Image vessels using a hollow needle, contrast agent and live radioscopy. -Technical options at the time were limited to inserting the needle into a vessel and injecting contrast agent directly through the same needle. As a result, not all target vessels could be imaged effectively. -In time, increasing the technical options. Vessel imaging became more and more selective, also for less accessible vessels as in the abdomen. -More and more techniques were developed for endovascular treatment of pathologic processes. Intervention radiology Indications: 1 Imaging of vessels for diagnostic purposes. 2 Therapeutic purposes like : Angioplasty of stenosed vessel. Stenting of stenosed vessel. Coil insertion in aneurysm. Thrombolysis (dissolution of blood clot). Embolization of vessels (non malignant conditions as bleeding) or (malignant conditions to stop blood supply to the targeted tumor). Intervention radiology  Intervention radiology General technique: -The initial procedures of vascular interventions are generally similar. -Access to the vascular system must be obtained (with the Seldinger technique). Intervention radiology -The blood vessel (artery or vein) is punctured with a hollow needle containing a guide wire. -This can be guided by palpation, or by ultrasound guidance is used in the interventional radiology department. -The needle is then withdrawn, leaving the guide wire in the vessel. -A kind of thick working tube, the sheath, can then be inserted over the guide wire. - At the end (outside of the patient) of the sheath is a valve preventing leakage of blood through the sheath. -Once the sheath has been placed, this provides stable access to the vascular system allowing several types of guide wires and catheters to be passed through. -Using live radioscopy, these guide wires and catheters can be maneuvered to the target region. Intervention radiology