PULMONARY CIRCULATION including anatomy.pptx

pulmonary circulation and technique of it demonstration

1. RADIOLOGICAL ANATOMY OF THE PULMONARY CIRCULATION AND TECHNIQUES OF ITS IMAGING By DR. MOHAMMED YAHAYA RADIOLOGY DEPT. FTH GOMBE

2. Outline Introduction Radiological Anatomy -Plain chest radiography -Pulmonary angiography -Pulmonary echocardiography -CT/CTPA/CTPV -MRI/MRPA/MRPV -Radionuclide Lung V/Q imaging Techniques -Plain chest radiography -Pulmonary angiography -CT/CTA -MR/MRA -Radionuclide lung V/Q imaging Conclusion

3. Introduction The pulmonary circulation is made up of pulmonary arteries and pulmonary veins. The pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs. The pulmonary veins return oxygenated blood to the left atrium. The left and right pulmonary arteries arise from the pulmonary trunk typically, four pulmonary veins drain into the left atrium.

4. PA chest radiograph Pulmonary vasculature The vessels account for most of the lung markings. The pulmonary trunk forms part of the left border of the heart. Bronchi and arteries are seen together radiating out from the hila . The hilar point is where the upper-lobe vein crosses the descending pulmonary artery. The right hilar point is projected over the sixth posterior interspace and is 1 cm lower than the left. The hilar angle is the angle between the vessels at the hilar point - normally 120°.

5. Pulmonary vasculature The interlobar artery is seen lateral to the bronchus intermedius on the right (should not measure more than 16 mm midway down its visible length) Pulmonary veins enter the mediastinum lower than the arteries as they converge toward the posterior aspect of the left atrium. This means that; In the upper zone the veins are inferolateral to the arteries; and In the lower zone the veins are almost horizontal and the arteries almost vertical. The inferior pulmonary veins drain anteriorly and superiorly from the lung bases to the left atrium. Owing to their more horizontal course, if seen end-on on the chest film they may simulate a pulmonary mass.

6. Plain chest radiograph The left main pulmonary artery (white arrow) arches over the left main bronchus and is higher than the right pulmonary artery (blue thick arrow) which passes in front of the right main bronchus. The left pulmonary veins (horizontal black arrows) are seen superior and posterior to the right pulmonary veins (vertical black arrows). ↙ ← ↑ ↑ →

7. Lateral chest radiograph The pulmonary arteries may be seen at the hilum forming a conglomerate density with the pulmonary veins . The right pulmonary artery is seen end-on and is oval in appearance. The left pulmonary artery is comma-shaped as it arches over the left main bronchus. They may each measure up to 3 cm in diameter. The confluence of the pulmonary veins is seen below the oval density of the right pulmonary artery on the lateral film . The superior veins are more anterior than the inferior pulmonary veins.

8. Pulmonary angiogram MPA MPA-main pulmonary artery RPA-right pulmonary artery LPA-left pulmonary artery 1-superior trunk/ truncus anterior 2-inferior trunk/ interlobar artery 3-apical segmental artery (A1) 4-anterior segmental artery (A3) 5-posterior segmental artery (A2) 6,7,8,9-subsegmental arteries 10-RML segmental artery,lateral (A4) 11-RML segmental artery,medial (A5) 12,13-subsegmental arteries of the RML A4a,A4b 14-artery to the superior segment (A6) 15-pars basalis /basal trunk 16-medial basal segmental artery(A7) 17-anterior basal segmental artery(A8) 18-lateral basal segmental artery(A9) 19-posterior basal segmental artery (A10) RPA LPA 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

9. MPA RPA LPA MPA-main pulmonary artery RPA-right pulmonary artery LPA-left pulmonary artery 1,2,3,4-segmental branches to the LUL and lingula (A1,A2) ASPA-anterior segmental pulmonary artery (A3) IA- interlobar artery SAS-superior apical segmental artery(A6) 5-anterior basal segmental artery (A7+8) 6-lateral basal segmental artery (A9) 7-posterior basal segmental artery (A10) 1 2 3 4 ASPA IA SSA BT 5 6 7

10. Pulmonary angiogram DSA Vessels appear as lucent tubular branching. Subdivisions are as above.

11. Pulmonary venogram 1 2 3 4 5 1,2,3-right pulmonary veins 4,5-left pulmonary veins

12. Pulmonary trunk echocardiography (suprasternal long axis view)

13. CT Pulmonary angiogram

14. CT Pulmonary angiogram 1. Body of T5 2. Sternum 3. Spinous process of T5 4. Ascending aorta 5. Descending aorta 6. Superior vena cava *7 . Main pulmonary trunk *8 . Right pulmonary artery *9 . Left pulmonary artery 10. Carina 11. Left main bronchus 12. Oesophagus 13. Azygos vein 14. Azygo -oesophageal recess 15. Mediastinal fat

15. MR/MRA

16. Radionuclide lung ventilation/perfusion V/Q imaging This shows normal lung ventilation and perfusion. In the ventilation- air reached both lungs In perfusion- blood circulated well in both lungs .

17. Pulmonary arteries variants -The right and left hilar points are at the same level in 3%. On the Right ; Upper lobe; In 50%, the pulmonary arterial supply to the posterior segment is split between an ascending artery from the interlobar artery, and a recurrent artery from the truncus anterior In approximately 33%, the posterior segment’s sole supply is from the ascending artery In 15%, the posterior segment is fed entirely from the truncus anterior in which case there may be no ascending artery Bifurcation of the ascending branch of the RPA into superior and inferior trunks ( truncus anterior superior and inferior ) is seen in approximately 15-20%   Additional or replaced supply of  the anterior segment can be seen from the ascending artery (in approximately 25% of individuals) or from the inferior trunk (in approximately 15 %)

18. Right Middle lobe; Three separate trunks may be seen instead of two The medial and lateral segmental arteries (A4 or A5) may have a common origin with a lower lobe segmental artery. A branch of the medial segmental artery may cross segmental boundaries and supply the anterior aspect of the lateral segment Right Lower lobe;   In approximately 20% of individuals, the artery to the superior sement (A6) arises as two or very rarely three separate arteries from the right lower lobe artery    Two of the subsegmental arteries may have a common Trunk Any two basal segmental arteries may arise as a common trunk ( eg . A7 and A8 may arise as a common trunk, A7+8) A subsuperior pulmonary segment is seen in approximately 30% of individuals, located between the superior and basal segments of the lower lobes bilaterally

19. Pulmonary arteries variants On the Left; Two to seven branches may originate from the proximal LPA to supply the left upper lobe and lingula The anterior apical subsegmental (A3) arteries may arise as separate branches from the LPA Occasionally , A3 may arise from the posterior aspect of the LPA The apical segmental arteries may arise as common trunks with subsegmental arteries In approximately 15% of individuals, all three subsegmental arteries arise as a common stem The lingular arteries (superior lingular , A4; inferior lingular , A5 ) may arise as a single trunk or as two separate arteries.

20. Pulmonary veins variant anatomy Variant configurations are seen in about 30% of individuals and are more common on the right. Common trunks common draining trunk of left superior and inferior pulmonary veins Accessory (additional pulmonary veins) single accessory right middle pulmonary vein (~10%) two accessory right middle pulmonary veins one accessory right middle pulmonary vein and one accessory right upper pulmonary vein  superior segment right lower lobe vein  basilar segment right lower lobe vein right superior pulmonary vein (drains right superior basal segment)   

21. Techniques

22. Conventional angiography Pulmonary angiography was traditionally considered the “gold-standard” for imaging the pulmonary vessels and for detecting most pulmonary emboli but has now been replaced largely by multi-detector CT. It is an invasive procedure and uses ionising radiation and iodinated contrast medium. Indications Pulmonary emboli Pulmonary artery stenosis Pulmonary artery A-V malformations Catheter-directed thrombolysis/ catheter embolectomy Contraindications Include general contraindications to any angiography such as Bleeding diasthesis , Contrast allergy and renal failure Specific contraindications such as; E levated right ventricular end diastolic pressure >20mmHg Elevated pulmonary artery pressure >70mmHg Left bundle branch block

23. Contrast LOCM 370mgIml -1 @ 20-25mls -1 . , 0.75 ml/kg (max. 40ml) Equipment Fluoroscopy unit on a C- or U-arm with digital subtraction facilities Pump injector Catheter pigtail (coiled end, end hole and 12 side hole) Equipment for Seldinger technique Others; ECG monitoring, pressure recording device, resuscitation equipment

24. Patient preparation Informed consent The patient will require hospital admission for careful preparation and observation before and after the procedure respectively. Allergies , particularly to intravenous contrast material or other procedural medications such as sedatives If the patient is on anti-coagulant treatment, the clotting profile should be within acceptable limits. Beta-blockers should be stopped 48hrs before the procedure Echocardiography -ECG abnormalities: LBBB Vital signs, renal function tests Platelet count >50,000/mm3 The patient should fast overnight but be well hydrated Pregnancy test (if appropriate) The charts and radiographic films should be reviewed.

25. . Technique Supine on exam table. Seldinger technique to insert and advance the catheter via the femoral vein (or right internal jugular vein) After gaining central venous access , the catheter is advanced into the right atrium under fluoroscopic guidance . Continuous cardiac monitoring is imperative to assess for arrhythmia as the catheter traverses the heart. The catheter is advanced under fluoroscopic guidance until it lies 1-3cm above the pulmonary valve. Pulmonary pressures are monitored throughout the procedure. Injection rates are as follows: Main pulmonary artery, 25-30 mL/s for 2 seconds Left pulmonary artery or right pulmonary artery, 15-20 mL/s for 2 seconds Lobar or segmental, 5-10 mL/s for 2 seconds

26. Measuring pressures in the heart and pulmonary arteries may be necessary, especially when evaluating a patient with chronic thromboembolic disease. Typically, pressures in the right atrium, RV, and main pulmonary artery are measured. Normal pressure values are as follows: Right atrium or central venous pressure, 3-5 mm Hg RV, 20-25 mm Hg Pulmonary artery, 20-25 mm Hg/10-15 mm Hg Pulmonary capillary wedge, 10-15 mm Hg

27. Image acquisition To obtain a diagnostic pulmonary angiogram, the patient suspends respiration after a full inspiration during the injection of contrast medium and a frontal chest radiograph is taken. If the entire chest cannot be accommodated on one field of view the examination can be repeated by examining each lung. The catheter is advanced to lie in each main pulmonary artery in turn. For the right lung the patient or tube is turned 10 LPO and for the left 10 RPO

28. For optimal visualisation of the right and left pulmonary arteries, pulmonary valves and pulmonary trunk, a 40 cranio -caudal view is taken. With this manouvre the pulmonary trunk is not forshortened and it is not super-imposed over its bifurcation. At the end of the procedure, the catheter is withdrawn and compression of the puncture site should be maintained for 5-10 minutes . In pulmonary venography, the indications include AVM, pulmonary veins varix or stenosis and is usually done in combination with pulmonary arteriography. However, images are acquired in the venous phase when the pulmonary veins are opacified as they drain into the left atrium.

29. . In addition, pulmonary venography can be done retrogradely in patients with patent foramen ovale by passing the catheter into the left atrium from the right atrium and then contrast is injected retrogradely. Or The femoral artery is catheterised and the catheter is advanced into the right atrium and images are acquired as in pulmonary arteriography. Aftercare; bed rest for at least 4hours puncture site observation pulse and bp half-hourly for 4h, then 4-hourly for 20 hours

30. Due to Contrast Medium Due to Technique Nausea Hemorrhage/hematoma Vomiting Catheter knotting Urticaria Catheter breakage CVS collapse Guide-wire breakage Neurotoxicity Air Embolism Anaphlylactic reaction Thrombosis Convulsion A-V fistula Nephrotoxicity Septicemia

31. Technique of PA chest radiograhy Position of patient and cassette • The patient is positioned facing the cassette, with the chin extended and centred to the middle of the top of the cassette . • The feet are paced slightly apart so that the patient is able to remain steady. • The median sagittal plane is adjusted at right-angles to the middle of the cassette. The shoulders are rotated forward and pressed downward in contact with the cassette. • This is achieved by placing the dorsal aspect of the hands behind and below the hips, with the elbows brought forward, or by allowing the arms to encircle the cassette. Direction and centring of the X-ray beam • The horizontal central beam is directed at right-angles to the cassette at the level of the eighth thoracic vertebrae (i.e. spinous process of T7), which is coincident with the lung midpoint • The surface marking of T7 spinous process can be assessed by using the inferior angle of the scapula before the shoulders are pushed forward. • Exposure is made in full normal arrested inspiration

32. Transthoracic echocardiography (TTE) Is a non-invasive radiological imaging technique that uses ultrasound waves to visualise the mediastinal structures. Indications Pulmonary emboli Pulmonary artery stenosis Pulmonary artherosclerosis Evaluation of pulmonary valves Equipment Ultrasound machine Curved linear probe 1-5 Mhz with Color Doppler capabilities. Ultrasound gel +/-ECG monitor with appropriate chest leads

33. . Patient preparation Patient assessment- hx / risk of peripheral vascular disease, HTN, etc Obtain informed consent Technique The patient lies supine on the examining couch. The patient is asked to lift their chin upward (hyperextend the neck) and look to the right or left ie . Turn 45 to either side The suprasternal pulmonary trunk long axis can be imaged with the probe marker turned clockwise to the 5 o'clock position, roughly perpendicular to the long axis view . Other approaches; Suprasternal short axis Parasternal long and short axis views

34. measurements of the maximum diameters and wall thickness are taken in all planes. Grey-scale US- vessel wall assessment (vessel diameters), intimal thickening or calcifications Pulsed-wave Doppler- PSV-Peak Systolic velocity, EDV- End Diastolic velocity Color flow Doppler- displays flow as color superimposed in the arterial lumen on grey-scale imaging Power Doppler- a modified color Doppler (more sensitive to slower flows)

35. CT/CTA Although CTPA involves the administration of iodinated CM and significant radiation dose, its advantages include that it is rapid usually taking <30s, unstable patients can be evaluated, the vessels and their surrounding structures can be assessed. Indications Pulmonary emboli A-V malformations Congenital pulmonary artery disease Pulmonary artery/vein stenosis or varix Contraindications Hypersensitivity to CM Bleeding disorders/coagulopathy Anti-coagulant medications Pregnancy Contrast LOCM 240-320mgI/ml 100-150mls when using a dual-phase injector or 80-100mls followed by saline injection 30-50ml @ a rate of 4-5ml/s Equipment Multi-detector CT suite (16 or 64 slice) Syringe Canula

36. Patient preparation Obtain informed consent Patient assessment- history / risk of peripheral vascular disease, HTN, etc . Patient removes clothing and metallic objects (earrings, watch, necklace, etc.) and wears the exam gown Technique The patient lies supine head first on the scanner table. Positioning is aided by the use of transaxial, coronal and sagittal external alignment lights. The median sagittal plane is perpendicular and the coronal plane is parallel to the scanner table. The scanner table height is adjusted until the coronal plane is at the level of the mid-axillary line. The patient is then moved into the scanner so that the scan reference point is at the level of the sternal angle.

37. The patient is then moved into the scanner until the scan reference point is at the level of the sternal angle. A anteroposterior scan projection radiograph is performed, starting at the 10cm above and terminating at 25cm below the scan reference point. From this scan image 10mm contiguous sections are prescribed from the lung apices to a point just below the lowest costophrenic angle. Images should be taken during suspended respiration. These pre-contrast images are reviewed and any abnormalities are noted during the infusion of contrast medium using the same imaging protocol. Contrast is then injected through a peripheral vein @3-4mls/s with a preset delay of approx. 15s for single slice scanner, 22s for 16 slice scanner and 26s for 64 slice scanner CT. Or Using bolus tracking technique, with the ROI positioned over the pulmonary artery at the level of the carina Post-processing image review settings + their levels; Mediastinal window Pulmonary embolism specific window Lung window

38. MRI/MRPA Method: +Excellent in soft tissue details +Does not employ the use of ionising radiation +Sensitivity and specificity comparable to those of CTPA -Relatively expensive Indications Pulmonary emboli A-V malformations Congenital pulmonary artery disease Pulmonary artery/vein stenosis or varix

39. Contraindications: -MRI non-compatible ferromagnetic implants - Pacemakers -Claustrophobia (relative) Contrast: 0.1ml/kg Gd - DTPA Equipment MRI machine Syringe Canula

40. Patient preparation Technique The patient lies supine head first, on the scanner table with the median sagittal plane perpendicular to the centre of the table. Using external alignment lights the external reference point is obtained at the level of the manubrium. The radiofrequency coil is placed over the chest. The patient is moved the fixed distance into the isocentre of the magnet which is also the centre of the radiofrequency coil. An initial T1W coronal localiser is obtained. From this image, transaxial T1W and T2W, sequences are prescribed. After iv contrast injection, other sequences are obtained. Other sequences; T1W+C, TOF, PC-MRA, Gated subtraction fast-spin echo

41. Ventilation/Perfusion (V/Q) Imaging V/Q imaging involves the use of scintigrams of pulmonary perfusion and ventilation are performed after application of intravenous radioactive isotopes labeled with technetium 99 m to provide functional vascular and airway detail.   Indications suspected pulmonary embolus assessment of regional lung function Contraindications Asthma COPD C ardiac failure Pregnancy Pulmonary hypertension

42. Radiopharmaceutical   99 Tc-radiolabeled macroaggregated albumin (99Tcm-MAA ), 100 MBq Or 99Tcm Diethylene triamine-pentacetic acid (DTPA) is administered via a nebuliser of which the patient should receive an administered activity not exceeding 80MBq in the lungs. Other ventilation agents; Xenon-133, Xenon-127, Krypton-81m Equipment LFOV camera with a general purpose collimator Canula Syringes Patient preparation A chest x ray is recommended within 24hrs prior to the study Immediately prior to injection, the syringe should be gently inverted a few times to ensure re-suspension of the particles.

43. Technique The patient lies supine on the exam table. The radiopharmaceutical should be injected with patient supine. Blood must not be drawn back into the syringe. Patient inhales the ventilation agent via a mouth-piece with a disposables breathing unit. The patient should be imaged, if possible, in the same position for both ventilation and perfusion imaging, unless the patient’s clinical condition prevents this. Computer acquisition A 128 x 128 or 256 x 256 matrix should be used or a pixel size between 2 – 4mm. For lung perfusion 500K counts per view should be obtained. For lung ventilation using 99Tcm DTPA aerosol 100K counts per view.

44. Image interpretation; Homogeneity of tracer uptake Presence of clumping of aerosol and central airways deposition Perfusion and/or ventilation defects to include location, size and number Pitfalls- Hot spots on the perfusion image if clotting of blood occurs within the syringe prior to injection or clumping of particles within the syringe . Injection of 99Tcm MAA through a central line may result in particle adherence to the cannula and may also result in inadequate mixing in the pulmonary artery and lead to uneven distribution throughout the pulmonary artery territories . Previous pulmonary emboli may lead to persisting perfusion defects reducing the specificity of the test.

45. Aftercare The patient is encouraged to drink a lot of water/fluids over the next 24hrs to facilitate the excretion of the radiopharmaceuticals. Complications Rare

46. conclusion Radiological Anatomy of the pulmonary circultation and technique demonstrating its imaging

47. Thank you for listening