Radiographic examinations

• A source to image distance (SID) of 100 cm and a central ray (CR) at 90° to the image receptor (IR) should be assumed for all projections unless otherwise stated.

• Appropriate orientation of the IR is assumed, e.g. long axis of long bone/limb to long axis of IR.

• For projections of the axial skeleton and abdomen, anteroposterior (AP)/posteroanterior (PA), pelvis and abdomen, the mid-sagittal plane (MSP) should be perpendicular to the IR and the coronal plane parallel to the IR.

• For lateral projections of the axial skeleton, the MSP should be parallel to the IR and the coronal plane perpendicular to the IR.

• Appropriate use should be made of anatomical and procedural markers, collimation and radiation protection measures.

• Immobilisation devices may be employed where appropriate and necessary.

• Infection control procedures should be observed at all times.

• Relevant patient preparation is assumed, including removal of potential artefacts from the region of interest (ROI).

Abdomen

(see also Biliary tract; Diaphragm; Foreign bodies; Intravenous urography)

Acetabulum

(see also Hip; Pelvis)

Right and left posterior oblique projections (Judet views) are used to accurately locate acetabular fractures following an AP projection of the pelvis.

Additional modality

• CT may provide reconstructed three-dimensional images for better preoperative planning.

Acromioclavicular joint

(see also Shoulder)

To demonstrate subluxation of the acromioclavicular joint.

Acromion process

(see Shoulder)

Ankle

Additional projection

A fracture of the distal tibia or fibula could indicate a proximal contra-coup fracture at the proximal portion of either bone and projections of the whole tibia and fibula should be acquired if this is suspected.

• See Tibia; Fibula.

Alimentary tract

(see Barium studies; Foreign bodies)

Aorta (abdominal)

(see also Abdomen)

Additional modalities

• Ultrasound (US) is the modality of choice to demonstrate an aortic aneurysm as, unless there is associated calcification, plain radiography is equivocal.

• CT is used for detailed assessment of the extent of, and relationships to, the aneurysm.

Aorta (thoracic)

(see Chest)

Arthrography

Arthrography can be described as the direct injection of contrast agent(s) into the capsule of a joint to demonstrate its internal soft tissue anatomy. Single or double contrast techniques can be used. Single contrast studies utilise a water-soluble iodinated contrast agent, the amount required varying with the joint under investigation. Air is the additional contrast used in double contrast studies. Most often used in investigations of the knee joint but shoulder, hip, elbow and temporomandibular joints may also be imaged using this technique. The procedure is performed under strict aseptic conditions. Following the aspiration of any joint effusion the contrast agent(s) are injected into the joint. The joint is then manipulated to distribute the contrast material evenly. A mixture of fluoroscopic spot images and conventional radiographs of the region under investigation are generally acquired.

Contraindications include infection of the joint or overlying skin, and sensitivity to contrast media. Complications include joint discomfort, allergic reactions, chemical synovitis, pain, infection or capsular rupture.

NB: General anaesthesia may be required for investigation of the hip in children.

Additional modality

• Magnetic resonance imaging (MRI) has reduced the need for many of the arthrograms previously carried out in radiology departments.

Atlanto-occipital articulation

(see also Cervical vertebrae)

This projection demonstrates the atlanto-occipital joints visualised through the maxillary sinuses.

Autotomography

This describes the use of patient movement, as opposed to IR and tube movement in normal tomography, to blur areas not required on the image. The most common use currently is for imaging the lateral thoracic vertebrae. The standard projection is used but the exposure is altered to include a long exposure time, e.g. 1 second. The patient continues shallow breathing during the exposure in order to blur the ribs and obtain better detail of the vertebrae and joint spaces.

Barium enema (double contrast)

Single contrast procedures, although useful in some cases, do not provide a good demonstration of the mucosal pattern. A double contrast barium enema examination generally employs the use of both fluoroscopic and conventional radiographic techniques.

Patient preparation

Prior to the examination rigorous patient preparation is essential to rid the entire large intestine of all faecal matter as this can mimic the appearance of pathology, e.g. small tumours. Patient preparation is department dependent but in general consists of the patient having a low-residue diet for 2–3 days prior to the examination with fluids only on the day before the examination. A laxative is taken the morning and evening of the day before the examination. If a bowel cleansing enema is required, it can be carried out on the day of the examination, making sure enough time is left before commencing the procedure to allow the colon to absorb the excess water this produces. Preparation is modified in patients with a predisposing condition which may be exacerbated by the usual departmental regime. In order to get the best diagnostic information from what can be a demanding examination, it is necessary to give the patient a full and comprehensive explanation of the procedure.

Technique

• Unless there is a suspicion that bowel preparation is inadequate or toxic megacolon is suspected, a control image of the abdomen is not necessary.

• A lubricated enema tube is introduced into the rectum.

• An intravenous injection of a muscle relaxant is given which will reduce bowel peristalsis for the duration of the examination.

• The barium suspension is introduced under fluoroscopic control until it reaches the hepatic flexure.

• Spot radiographs of the bowel are taken as per department protocol and where indicated throughout the procedure.

• The barium suspension within the sigmoid colon is allowed to drain out.

• Air is gently pumped into the bowel to push the barium towards the caecum, dilate the colon and produce the double contrast effect. Patient position is manipulated to allow the barium suspension to coat the bowel mucosa.

Basic projections

Patient aftercare

The patient should be monitored until any side effects produced by the muscle relaxant have subsided. The patient should be warned that their bowel motions will be white for a few days. As residual barium suspension can cause constipation, the patient should be advised to increase their water intake.

Barium meal and follow through

A double contrast approach is preferred as this increases visualisation of the mucosal pattern. A barium sulphate suspension and a gas-producing agent provide the double contrast effect.

Patient preparation

Nil by mouth for at least 8 hours prior to the examination. It is advisable that the patient does not smoke or chew gum after midnight on the evening before the examination as both these activities increase gastric motility which is detrimental to the procedure.

Basic projections

Spot films under fluoroscopic control with patient erect

• Projections of the fundus of the stomach.

Patient aftercare

• As for barium enema.

Barium studies

Once the exclusive domain of radiologists, barium examinations of the gastrointestinal tract are now increasingly the remit of radiographers who have completed the appropriate postgraduate courses of study. All measures should be taken to keep the radiation dose to both patient and practitioner to a minimum. See Section 3 for the contraindications to the use of barium sulphate as the contrast medium of choice. Muscle relaxants and gas-producing agents can also produce side effects and have contraindications that should be considered before they are administered.

Barium swallow

Patient preparation

Not necessary unless the stomach is to be examined when patient preparation is as for a barium meal.

Patient aftercare

Although a small quantity of barium sulphate suspension is used, the patient should still be warned that their bowel motions may be white for a few days following the examination.

Bicipital groove

(see also Humerus; Shoulder)

To demonstrate the sulcus between the greater and lesser tuberosities on the anterior aspect of the humoral head, wherein lies the biceps tendon.

Biliary tract

Although ultrasound is now the modality of choice, the following radiographic examinations are still performed. Contrast media can be introduced into the biliary tract orally, intravenously or by direct injection into the ducts. Each examination is named according to the route of entry and the portion of the biliary tract examined.

Additional imaging

To demonstrate gall bladder function (currently rarely used).

Oral cholecystography

• The control film is taken the day before the examination, and a morning appointment arranged.

• The patient is advised to eat a light evening meal, containing no fats, prior to the examination.

• The preparatory contrast medium is taken 12 hours before the examination is due.

• No further food should be consumed although water may be taken up to 8 hours before the examination.

• A second dose of contrast may be given prior to the examination.

• Erect and prone LAO projections of the gall bladder region are acquired.

• If the gall bladder is visualised on these images, a proprietary fatty meal is given to the patient.

• A coned image in the prone LAO position is taken after 30 minutes to assess gall bladder contraction.

• In the event of the gall bladder not being demonstrated, a further examination can be carried out on the following day after a second dose of contrast.

Additional imaging

To demonstrate the patency of the common bile duct and confirm/deny the presence of any retained calculi prior to removal of the gall bladder. This examination is carried out during surgery.

Additional imaging

To guide removal of calculi percutaneously where the T-tube is withdrawn before a catheter is passed along the remaining tract. The tip is placed just beyond the calculus allowing a basket to be inserted and opened beyond the calculus. This is slowly withdrawn and the stone grasped. This procedure is carried out under fluoroscopic control.

Additional imaging

Imaging of the pancreatic and biliary ducts following the introduction of a contrast medium directly into the pancreatic duct. Indications for the procedure include jaundice and pancreatic disease. The patient requires sedation.

Endoscopic retrograde cholangiopancreatography (ERCP)

• With the patient on their left side the endoscope is introduced under fluoroscopic control until the ampulla of Vater is located.

• A cannula is passed through the endoscope and the patient pronated.

• The contrast medium is introduced to determine the correct positioning of the cannula.

• On finding calculi in the bile ducts, coned images in the prone and both oblique positions are taken.

• Images taken in the Trendelenburg position will demonstrate the intrahepatic ducts.

• To demonstrate the pancreas, coned images in the prone and both oblique positions are required.

• Delayed images may show the gall bladder (if present) and common bile duct emptying.

• To demonstrate the pancreatic duct a low-osmolar (240 mg/ml) contrast medium is used.

• To demonstrate the bile ducts a low-osmolar (150 mg/ml) contrast medium is used.

Additional modalities

• US is the modality of choice as it demonstrates good visualisation of the liver parenchyma, gall bladder and ducts, although the pancreas is not always well demonstrated. It is non-invasive, generally readily available and with no radiation dose to the patient. Indications include pain, jaundice, acute pancreatitis and assessment of gall bladder function or gallstones. The only preparation required is the need for a patient to fast. Ultrasound can also be used to guide percutaneous procedures.

• CT provides good visualisation of the pancreas, liver, gall bladder and ducts.

• MRI in the form of magnetic resonance cholangiopancreatography (MRCP) provides excellent visualisation of the biliary tract, pancreatic duct and gall bladder without contrast media administration, instrumentation or radiation and therefore entails less risk than ERCP.

• RNI for acute cholecystitis can identify an obstructed gall bladder from a hepatobiliary iminodiacetic acid (HIDA) scan. Biliary scintigraphy can also be of use in chronic cholecystitis.

Bitewing radiography

To demonstrate the crowns of the upper and lower premolar and molar teeth in occlusion, on one IR. The long axis of the IR can be placed horizontally or vertically as per clinical indications. The interdental spaces should be well demonstrated if the IR is parallel to the teeth and the CR perpendicular to both.

Basic projections

It is recommended that IR holders and a beam aiming device are used to aid accurate patient positioning and the correct alignment of the x-ray tube head. This will help to ensure optimum image quality and avoid the common fault of cone cutting. A bitewing acquired using the traditional detachable tab is operator dependent and not generally reproducible.

Premolar region

• Positioning as above with appropriate alteration to the position of the x-ray tubehead.

• Using the beam aiming device, the CR is directed through the contacts of the teeth.

Bladder

(see also Cystography; Cystourethrography; Intravenous urography)

Basic projection

AP

• Patient supine with no rotation of the pelvis.

• 15° caudal angulation to the MSP.

• Centre 5 cm above the upper border of the symphysis pubis.

Additional modality

• US is now more often the modality of choice for bladder investigation in the first instance.

Bone age

(see Wrist)

To establish the skeletal age of a child with retarded development of stature for chronological age, e.g. in Perthes’ disease. The PA projection of the left wrist is usually taken for comparison with images from the Greulich and Pyle ¹ Atlas or for use with the Tanner and Whitehouse² scoring system.

Breast

(see Mammography)

Bronchi

(see Chest; Foreign bodies)

Calcaneum

(see also Ankle; Foot)

Additional projection

To demonstrate calcaneal spur and Severs’ disease (osteochondritis).

Lateral

• Projection of affected calcaneum.

NB: These patients can often be managed without imaging.

Carpal tunnel

(see also Wrist)

Cephalometry

Used in orthodontic assessment to ensure standardisation of patient position and allow comparisons to be made throughout a course of treatment. The procedure allows specific measurements to be made within the facial skeleton.

Fastest Radiology Insight Engine

2: Index of radiographic examinations

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