HETI SPONSORED RADIOLOGY ESSENTIALS TEACHING Dr Noel Young Department of Radiology Westmead Hospital

BASIS OF THIS TALK Recommendations to HETI by Intern / RMO advisory group.

OTHER CONSIDERATIONS Should follow your University Imaging teaching. Key points of: recognising key pathologies, understanding clinical contexts for radiology requesting understanding context of reports per individual patient requirements / status, keeping your boss happy.

With PACS in all NSW public hospitals, seeing all patients’ images is easy. But interpretation is still the big issue.

DIFFERENTIAL FORCES IN RADIOLOGY Cost to Government Cost to patient Radiation cost to patient VS Keeping patients happy Keeping lawyers at bay Differential clinical needs

TALK DIVIDED INTO THREE PARTS Part I – CT Brain Part II – CT Abdomen and Pelvis Part III – Abdominal Ultrasound (A) – + Doppler Ultrasound (B)

Key Learning Objectives PART I: CT BRAIN Key Learning Objectives When / what to request - contrast issues sedation issues How to look at a CT Brain. Common pathologies.

Question: When to request? Answer: When your boss wants it. (Side issue – 4 hour Emergency objectives) Real test – how to get Radiology to do it. Answer: Communicate (best done by going to the Department)

Question: When to sedate? Answer: Whenever you want nice pictures and patient non-cooperative. When patient is crashing. (n.b. - be nice to your anaesthetist! – you have little that anaesthetists need!)

Question: How to interpret? Answers: Remember normal anatomy Look systematically – ask key questions - is there raised ICP is there blood is there an infarct is there normal white / grey differentiation Go ask someone more experienced (n.b. - Your university should have taught this stuff – you have already paid for it!).

COMMON PATHOLOGIES TO RECOGNISE Raised ICP Recent territorial infarct Blood - EDH (be careful!) - SDH - SAH - focal haematomas

Right old middle cerebral artery infarct. 1. No mass effect. 2 Right old middle cerebral artery infarct. 1. No mass effect. 2. Margins of the infarct are well defined.

CT – recent left PICA infarct involving the cerebellum. 1 CT – recent left PICA infarct involving the cerebellum. 1. Ill defined low density change. 2. Mass effect with compression of the 5th ventricle.

CT – Acute right posterior cerebral artery infarct, involving the occipital lobe. 1. The area of low density is ill-defined. 2. Local mass effect is present.

CT – Acute infarct of right cortical hemisphere. 1 CT – Acute infarct of right cortical hemisphere. 1. Loss of grey-white differentiation. 2. Compression of right lateral ventricle.

Small extra-dural – right temporal region. Note the lentiform shape

Small left acute extra-dural haemorrhage Small left acute extra-dural haemorrhage. Local mass effect with cortical sulcal effacement is present.

CT – Large right extra-dural haematoma. Significant mass effect.

CT – Acute left subdural haematoma. Massive mass effect CT – Acute left subdural haematoma. Massive mass effect. Significant shift of midline structures to the right. Note crescent shape of haematoma.

Diffuse intraventricular blood and subarachnoid haemorrhage Diffuse intraventricular blood and subarachnoid haemorrhage. There is effacement of sulcal spaces globally indicating raised intracranial pressure.

Diffuse intraventricular blood and subarachnoid haemorrhage Diffuse intraventricular blood and subarachnoid haemorrhage. There is ventricular dilatation.

Subarachnoid haemorrhage involving the basal cisterns.

Left sylvian fissure and traumatic subarachnoid haemorrhage Left sylvian fissure and traumatic subarachnoid haemorrhage. A subtle finding. Due to a small, ruptured, left MCA aneurysm.

1. Right subdural chronic haematoma. It is low density. 2 1. Right subdural chronic haematoma. It is low density. 2. Small amount of more recent blood (higher density) anteriorly.

IV CONTRAST ISSUES Iodinated, isotonic contrast used. Beware bad renal function (when pre-med with NAC, don’t forget the saline). Beware history iodine allergy YES – allergy exists (anaphylaxis!) Every hospital has a pre-med protocol

CT BRAIN (SURVIVAL KIT) Is there white stuff around (blood)? Is there dark stuff around (infarct)? Is there raised intracranial pressure (can’t see sulci or cisterns)?

PART II: CT ABDOMEN / PELVIS Key Learning Objectives When / what to request - contrast (IV and oral) issues How to look at a CT abdomen. Common pathologies.

Question: When to request? Answer: When your boss tells you. Question: What to request? Answer: Go ask your friendly neighbourhood radiologist (n.b. - please supply relevant clinical information).

HOW TO INTERPRET Actually, CTs of the abdomen are a lot more complex than CTs of the brain. Need best images to have a fighting chance.

HOW TO INTERPRET Remember what they taught you at University. Be systematic, follow the anatomy.

HOW TO INTERPRET General principles Does the liver look OK - is there a tumour are the bile ducts dilated is there a collection Does the pancreas look OK - is there a mass is it swollen is there fluid around it

HOW TO INTERPRET General principles continued Is there free peritoneal gas Is there free peritoneal fluid Is there a peritoneal collection Are there renal collecting systems dilated Is the aorta too big Is there blood around the place

COMMON PATHOLOGIES Perforation free intraperitoneal gas can see on CT little as 5 ml look in anterior abdomen look in region falciform ligament of liver (n.b. - post abdomen surgery, free gas can persist up to three weeks)

COMMON PATHOLOGIES when large bowel >5 cm diameter b. Obstruction when large bowel >5 cm diameter when small bowel >3 cm diameter actually better seen on plain AXR CT better to define masses bowel wall thickening

COMMON PATHOLOGIES if caecum >9 cm diameter – risk of perforation b. Obstruction continued if caecum >9 cm diameter – risk of perforation beware toxic megacolon (gas and wall thickening in transverse colon) look for other lesions

COMMON PATHOLOGIES fluid densities round, walled main scenarios c. Collection fluid densities round, walled main scenarios around pancreas in pancreatitis in subphrenic spaces in pelvis after bowel surgery

CT – very dilated intrahepatic bile ducts.

CT - Metastases – gross ascites with tumour in peritoneum.

CT – 1. Ascites – due to peritoneal metastases. 2 CT – 1. Ascites – due to peritoneal metastases. 2. Metastasis to right lobe liver.

CT - acute cholecystitis. 1. Thickened gallbladder wall. 2 CT - acute cholecystitis. 1. Thickened gallbladder wall. 2. Fluid around gallbladder.

Subphrenic collection and percutaneous drain.

Subphrenic collection and percutaneous drain.

Severe, acute pancreatitis. 1. Diffuse pancreatic necrosis. 2 Severe, acute pancreatitis. 1. Diffuse pancreatic necrosis. 2. Calcified gallstones.

Acute pancreatitis & gallstones. Severe pancreatic necrosis.

CT – small pancreas pseudocyst, following previous pancreatitis.

CT - Rectus haematoma – on Warfarin. The blood is layered.

CXR – 1. Right subphrenic abscess. 2. Right subpulmonic pleural fluid.

CT – Mild appendicitis. Thickened wall of appendix.

CT – 1. Recto-sigmoid carcinoma, mass-like lesion. 2 CT – 1. Recto-sigmoid carcinoma, mass-like lesion. 2. Metastases to liver.

CT – Severe appendicitis

CT ABDO / PELVIS (SURVIVAL KIT) Is there free gas? Are bowel loops dilated? Is there a lump in the liver? Is the pancreas swollen? Are the renal collecting systems too big? (these are >90% of conditions you need to identify)

PART III (A): ABDOMINAL ULTRASOUND Key Learning Objectives When to do Ultrasound VS When to do a CT Patient considerations - fasting size How to interpret

Question: When to do an Ultrasound? Answers: if looking at gallbladder and biliary tree pathology if pregnant in Emergency - portability

Question: What can’t be seen on Ultrasound? Answer: Actually quite a lot. Particularly - AAA (rupturing) free gas pancreatitis

Question: ? Fasting Answer: if looking for gallstones (otherwise gallbladder is contracted). Fasting for at least 6 hours. Question: When too big to bother? Answer: If over 100 kg Question: When to not bother asking for Ultrasound? Answer: Pretty much anytime after sun sets (n.b. – you can always get a CT)

HOW TO INTERPRET (1) Really quite hard Go do a course BUT …….. You are going to be expected to do it in the future …….in Emergency

HOW TO INTERPRET (2) Key things to look for Is the CBD too big – normal ≤7 mm Has the liver a “smooth” appearance Are there GB calculi Are the renal collecting systems diluted Is there an aortic aneurysm – normal ≤3 cm

Ultrasound – mild appendicitis. 1 Ultrasound – mild appendicitis. 1. The wall of the appendix is thickened. 2. No fluid around appendix.

Ultrasound - dilated biliary tree.

Ultrasound - dilated biliary tree. 1 Ultrasound - dilated biliary tree. 1. The channel in front is the dilated CBD. 2. The channel in the back is the portal vein.

Ultrasound – 1. CBD. 2. CBD is dilated at 1 cm.

Ultrasound – Acute cholecystitis. 1. Gallbladder is thickened. 2 Ultrasound – Acute cholecystitis. 1. Gallbladder is thickened. 2. The gallbladder lumen is filled with material.

Ultrasound - dilated renal collecting system.

Ultrasound - ureteric calculus causing the collecting system obstruction.

ABDOMINAL ULTRASOUND (SURVIVAL KIT) Is the bile duct dilated? Is there stuff in the gall bladder? Is the aorta too big? Are the renal collecting systems dilated? (these are >90% of conditions you need to identify).

PART III (B): ULTRASOUND DOPPLER Key Learning Objectives Indications Interpretation

Question: What are indications to request? I will change the question – What are the usual clinical scenarios? Presence of DVT in leg veins (most common) Presence of thrombus in arm veins (post-lines) Looking for abdominal AAA (CT is better) Looking for arterial ischaemia - leg arteries neck arteries

INTERPRETATION VASCULAR ULTRASOUND Very difficult Only for expert operators Best advice to you - Read the reports (not always done!) Go ask the reporter if you have a query.

Ultrasound of abdominal aortic aneurysm – transverse view.

Ultrasound of abdominal aortic aneurysm – longitudinal view.

Doppler ultrasound – right femoral vein – thrombus.

Doppler ultrasound – right femoral vein – thrombus in long view.

Doppler ultrasound – right ICA – plaque with stenosis.

Doppler ultrasound – right ICA – stenosis – colour flow image.

CLOSING COMMENTS This is a teaching file on subjects considered priority by previous RMOs OK BUT …… Plain AXR interpretation far more important for you guys early in your medical career.