Radiographic Techniques: Bones of the Thorax PDF

Radiographic techniques  Bones of the thorax  :BY Ahmed Jasem Abass  MSC of Medical Imaging Bones of the thorax  The thoracic skeleton consists of the ribs and sternum, and thoracic spine. The ribs and sternum may be examined radiographically in the a...

Radiographic techniques  Bones of the thorax  :BY Ahmed Jasem Abass  MSC of Medical Imaging Bones of the thorax  The thoracic skeleton consists of the ribs and sternum, and thoracic spine. The ribs and sternum may be examined radiographically in the assessment of trauma, but a good PA or AP radiograph will be more important in this setting to exclude intrathoracic complications. Oblique rib views performed for simple trauma cases unless a change in patient management will result, and an AP or PA projection will show much of the anterior and posterior ribs that are projected above the diaphragm.  In cases of severe injury to the thorax maintenance of respiratory function is of prime importance. Optimal PA or AP radiographs are required for full assessment of chest wall injury, pleural changes and pulmonary damage. In cases of major trauma, damage may occur to multiple ribs, sternum, lungs and thoracic spine, or any combination of these. Multiple rib and sternal fractures may result in a flail chest, where part of the chest collapses inwards in during inspiration, impairing or even preventing lung ventilation. In this setting a supine AP radiograph may be all that is attainable and it should be of the highest quality possible. A pneumothorax may be obscured on a supine radiograph, and in this situation a lateral radiograph is acquired using a horizontal beam. In major trauma cases injury to the clavicle and 1st ribs may indicate significant vascular injury, and these areas must be examined clearly on any frontal projection. Injury to the lower ribs may be associated with hepatic, splenic or renal injury, and rib projections may be requested in this situation. The ultrasound or CT may be considered more useful, for assessment of possible internal organ damage. Radiological considerations  Pain after rib trauma, reduce conspicuity of rib fractures and pulmonary contusion. Optimization of exposure and other factors therefore becomes more critical.  Overexposure may allow clearer image of rib trauma, but will tend to obscure associated pulmonary lesions, so should be avoided.  Fluoroscopy may be useful to determine whether a peripheral chest lesion is real and whether it is related to a rib, although CT is most likely to be requested in cases of doubt. Figure show x-ray shows a fracture on the left 7th rib at the posterior aspect Upper ribs  First and second – Antero-Posterior  18 × 24cm or 24 × 30 cm CR cassette is selected.  Position of patient and image receptor  The patient stands with the posterior aspect of the trunk against the vertical Bucky. Alternatively the patient lies supine on the Bucky table.  When the patient is erect, the cassette, is placed in a cassette holder.  The median sagittal plane is adjusted at right-angles to the image receptor.  The image receptor is centred to the middle of the clavicle. Direction and location of the X-ray beam  The collimated horizontal beam is directed perpendicular to the image receptor and centred to the middle of the clavicle. Upper ribs Cervical – Antero-Posterior (Figs 7.32c, 7.32d)  Cervical ribs are normally demonstrated on an AP cervical vertebrae or PA chest projection. 24 × 30 CR cassette is placed transversely on the Bucky tray.  Position of patient and image receptor  The patient sits or stands with the posterior aspect of the trunk against a vertical Bucky or lies supine on the Bucky table.  The median sagittal plane should be at right-angles to the image receptor and coincident with the midline of the table or Bucky.  The CR cassette is positioned transversely in the Bucky tray and should be large enough to include the 5th cervical to 5th thoracic vertebrae.  Direction and location of the X-ray beam  The collimated beam is angled 10° cranially from the perpendicular and centred towards the sternal notch. Cervical – Antero-Posterior (Figs 7.32c, 7.32d) Bones of the thorax (lower ribs)  Antero-posterior (basic)  35 × 43 cm CR cassette used to include the whole of the right and left sides from the level of the middle of the body of the sternum to the lower costal margin.  Position of patient and image receptor  The patient lies supine on the imaging table with the median plane coincident with the midline of the couch.  The anterior superior iliac spines should be equidistant from the couch top.  Bones of the thorax (lower ribs)  Radiographic techniques :- It is used to diagnose or treat patients by recording images of the internal structure of the body to assess the presence or absence of disease, foreign objects, and structural damage or anomaly.  Q What is the position of lower ribs?  A cassette is placed transversely in the Bucky tray with its lower edge positioned at a level just below the lower costal margin; otherwise the cassette is positioned to include the area of interest with its centre coincident with central beam. lower ribs  Direction and location of the X-ray beam  The collimated vertical beam is centred in the midline at the level of the lower costal margin and then is angled cranially to coincide with the centre of the image receptor.  This centring assists in demonstrating the maximum number of ribs below the diaphragm.  Exposure made on full expiration will also assist in this objective. lower ribs lower ribs Right and left posterior oblique  A table or vertical Bucky is employed or alternatively a 35 × 43 cm CR cassette is selected to include either the right or left lower ribs sides. The patient may be examined erect or supine.  Position of patient and image receptor  The patient lies supine on the Bucky table or stands erect with the mid-clavicular line of the side under examination coincident with the midline of the Bucky tray.  The trunk is rotated 45° to the side being examined with the raised side supported on non-opaque pads.  The hips and knees are flexed for comfort and to assist in maintaining patient position.  The lower edge of the cassette is positioned at a level just below the lower costal margin; otherwise the cassette is positioned to include the area of interest with its centre coincident with central beam. Right and left posterior oblique  The cassette should be large enough to include the ribs on the side being examined from the level of the middle of the body of the sternum to the lower costal margin.  Direction and location of the X-ray beam  The collimated vertical beam is centred to the midline of the anterior surface of the patient, at the level of the lower costal margin.  From this position the central ray is then angled cranially to coincide with the centre of the image receptor.  Exposure is made on arrested full expiration. Right and left posterior oblique Thank You