OSSEOUS SHOULDER
| Preparatory steps: | |||
| - | Indications: evaluation or verification of fracture/dislocation, bone tumours, degenerative, infectious, arthritic and osteonecrotic changes | ||
| - | Advisable preliminary investigations: always conventional radiography; MRI or ultrasonography may be alternative examinations without exposure to ionising radiation in non-traumatic disorders | ||
| - | Patient preparation: information about the procedure; restraint from food, but not fluid, is recommended, if intravenous contrast media are to be given | ||
| - | Scan projection radiograph: frontal from top of acromion extending 12-25 cm caudally, depending on suspected pathology | ||
| 1. | DIAGNOSTIC REQUIREMENTS | ||
| Image criteria: | |||
| 1.1 | Visualization of | ||
| 1.1.1 | Shoulder joint | ||
| 1.1.2 | Whole scapula | ||
| 1.1.3 | Proximal 8 cm or more of the humerus | ||
| 1.2 | Critical reproduction | ||
| 1.2.1 | Visually sharp reproduction of the bones (humerus, scapula, lateral end of the clavicle) | ||
| 1.2.2 | Visually sharp reproduction of the shoulder joint | ||
| 1.2.3 | Visually sharp reproduction of the musculature and other soft tissue structures | ||
| 2. | CRITERIA FOR RADIATION DOSE TO THE PATIENT | ||
| 2.1 | CTDIW | : | no specific value as yet available |
| 2.1 | DLP | : | no specific value as yet available |
| 3. | EXAMPLES OF GOOD IMAGING TECHNIQUE | ||
| 3.1 | Patient position | : | supine; if necessary slightly oblique; diseased shoulder as near gantry centre as possible with diseased arm along the body, the other arm above the head |
| 3.2 | Volume of investigation | : | humeral and scapular fracture/tumour: the fracture/tumour area; joint disorders: top of acromion to 1 cm below the glenohumeral joint |
| 3.3 | Nominal slice thickness | : | 3-5 mm, serial or preferably helical |
| 3.4 | Inter-slice distance/pitch | : | contiguous or a pitch = 1.0 in the joint region; 2-5 mm or a pitch up to 1.2-1.5 outside the joint region |
| 3.5 | FOV | : | shoulder dimension (usually 15-20 cm) |
| 3.6 | Gantry tilt | : | none |
| 3.7 | X-ray tube voltage (kV) | : | standard or high kV in large persons to avoid noise |
| 3.8 | Tube current and exposure time product (mAs) | : | should be as low as consistent with required image quality |
| 3.9 | Reconstruction algorithm | : | soft tissue/standard or high resolution |
| 3.10 | Window width | : | 1000-1500 HU (joints/bones) 200-600 HU (soft tissue) |
| 3.11 | Window level | : | 150-200 HU (joints/bones) 30-50 HU (soft tissue) |
| 4. | CLINICAL CONDITIONS WITH IMPACT ON GOOD IMAGING PERFORMANCE | ||
| 4.1 | Motion | - | movement artefact deteriorates image quality and the value of reconstructions (can sometimes be prevented by suspended inspiration) |
| 4.2 | Intravenous contrast media | - | useful for delineating malignant and inflammatory lesions extending into the soft tissue |
| 4.3 | Problems and pitfalls | - | immobility preventing correct positioning and causing artefact |
| 4.4 | Modification to technique | - | intra-articular contrast media for outlining intra-articular structures |