cardiovascular radialogy Flashcards
- imaging techniques of the heart
CHEST X-RAY
- Check pacemaker probes
- Assess position of a prosthetic cardiac valve
- Size of heart and check cardiopulmonary circulation in respect of pulm. effusion and cong. - Assessment of cavities of the heart in presence of volume and pressure loads (cardiomyopathy, valve defects, pulmonary hypertension, congenital defects etc.) - Normal size of heart is the same or less than half of transverse diameter of chest!! - Valves not normally visible, but visible due to calcifications or radiopaque valve replacement
- Cor hypertonicum cannot be seen on x-ray
- Increased volume loading can be seen as widened heart on lest side
- Left atrium: prominent auricle, double density, splayed trachea, dorsal displacement of esophagus
- Right atrium/ventricle: widening of cardiac silhouette to the right or front or increase in diameter of central pulmonary arteries
- Pericardial effusion: inconclusive for chest x-ray (USG, CT or MRI)
FLUOROSCOPY
control of pacemaker probes
check mobility of artificial heart valves
CT (MSCT)
- parenchyma, and chambers of the heart,
great vessels associated ( pulmonary trunk and aorta ) look for thrombosis/dissections
mediastinal tumors compressing heart(great vessels
- MSCT : best modality to view calcifications in coronary arteries, valves, aorta, pericardium
estimate risk of CHD.
MRI valvular disturbances ( endocarditis . see vegetations ) - indication: complex congenital defects in children, tumors, pericardial diseases, stroke volume assessment, valve stenosis assessment, blood flow quantification, size of myocardium, myocardial perfusion
Ultrasound - Echo
ultrasound of the heart - visualize real tine movement of the chambers of the heart
- TTE (transthoracic echocardiography) most commonly used
- In many cases the first imaging procedure
- Nearly every patient of cardiology is investigated by TTE or TEE
- Advantage: widespread availability, bedside investigation in acute situations - Disadvantage: depends on patients condition (overinflation of lungs)
- Indication (TTE): size of heart cavities and density of myocardium in left ventricle, assess function of LV (distinction between normokinetic, ischemic, akinetic (infarction) and dyskinetic (aneurysm), assess valve morphology and stenosis/insufficiency, diagnose pericardial diseases and tumors
- Indication (TEE): post-operative patients, intensive care, particularly ventilated patients, better resolution and assessment of cardiac structures in greater detail (valves, defects of atrium/ventricle, auricle)
CORONARY ANGIOGRAPHY (coronary H disease)minimally invasive - administer iv contrast though femoral/brachial/radial artery
- Vascular imaging modalities : evaluation of arteries using ultrasound - doppler / CTA
ultrasound - DOPPLER
- - Standard method for investigating of arteries and veins
- Basically all vessels accessible to ultrasound can be investigated
- Non-invasive and absence of radiation
- Classic indication is the investigation of supraaortic arteries (vertebral and carotids) + peripheral
- A major advantage is the possibility of measuring flow velocities by the Doppler technique
- detects the movement of blood cells in vessels and
provides colour mapping which corresponds to the
speed and the direction of the flow of blood within
that vessels
- the intensity of the colour represents the velocity of
flow
- One can thus draw conclusions about the degree of stenosis
- The higher flow acceleration, the higher is the grade of stenosis
- Arterial wall and plaque morphology can also be assessed well + shape and size of vessel lumen
normal blood vessel:
wall = hyperechoic (white)
lumen = anechoic (dark)
- Disadvantage: poor reproducibility of the investigation
doppler waveforms : arterial ( 3basic)
triphasic : normal ( systole / late systole / diastole)
biphasic : can be normal/abnormal (systole & diastole)
monophasic: abnormal
CTA
non-invasive method to visualization of vascular system
based on 3d reconstruction of image
iodine contrast - in right cubital ( to reduce artefacts)
used to see almost all arteries and veins
evaluates: dissections, stenosis, defects, ATS changes, calcifications, aneurysms …
- vascular imaging modalities : evaluation of arteries using MRA - ceMRA - DSA
MRA
no use of contrast medium
based on differences between stationary tissue and moving blood
- since stationary tissue is magnetically saturated by multiple repetitive radiofrequency pulses, the signal from inflowing blood appears paradoxically bright compared to background tissue.
uses :
diagnosis of ATS, aneurysms or abnormal vascular anatomy (CT displays anatomical details of blood vessels more precisely than MRA and ultrasound)
ceMRA
- contrast enhanced MRA is a technique involving #D spoiled gradient-echo sequences - with administration of Gd-based contrast (into central catheter or anticubital vien)
- Utilised to assess vascular structures of most parts of body
- Key features: T1-weightet spoiled gradient-echo sequence and use of Gd-based contrast to shorten T1-interval of the blood which appears bright as a result
Some form of fat supression - typically used in ceMRA ( because fat is the next brightest substance in the image after Gd)
DSA
- interventional and depict vessels
- special angiographic x-ray devices are used for the procedure
- Bases on the principle of fluoroscopy device with conventional x-ray and intraarterial CM (i) - Obtaining “freeze frame” because of the dynamicity of blood
- Non-contrast image subtracted from the contrasted one so bone structures are no longer
visible
- most common complication is hematoma
- Indication: diagnosis and treatment of occlusion, stenosis, embolism, acute limb ischemia, renal artery stenosis, AVM
SELDINGER TECHNIQUE :
- hollow needle + exchange wire + catheter
- guide wire into the lumen through needle
- remove the needle
- insert catheter into the lumen passing over the guide wire
- pathologies of aorta
standford classification of aortic dissection
diagnostic techniques
Endovascular treatments , types of endoleaks
o Aortic dissection:
- is an independent pathological entity
- Cause is usually degenerative arteriosclerosis, starting with an intimal tear or intramural bleeding from a vasa vasorum
- Stanford classification:
Type A ascending aorta (corresponds to De Bakey type 1 and 2),
Type B descending aorta (corresponds to De bakey type 3)
symptoms: retrosternal pain + shock - CT for diagnostic investigation
- Diagnostic evaluation: Rupture, hemorrhage, True/false lumen, Involvement of side branches, diameter
true lumen : smaller + outer wall calcification
false lumen: larger + lower contrast density - Treatment: stent grafts, important to be aware of the true and false lumen, and the proximanl entry site, which must be covered
o Thoracic aortic aneurysm:
- Arteriosclerotic (75-85%) or dissecting (15%) or very rarly inflammatory, mycotic or post traumatic
- Arteriosclerotic: distal to aortic arch usually, fusiform or saccular, calcified often, advanced age, associated with hypertension
o Abdominal aortic aneurysm:
- Arteriosclerosis
- 2% of persons above 60
- usually calcified
- starts in infrarenal aspect (95%) and extend often though the bifurcation into pelvic arteries - no symptoms usually
- abdominal pain and pulsating sensation when growing
- hypertension
- often additional involvement of coronary arteries and intermittent claudification - CT
- Rupture
o Inflammatory AAA:
- 5-10%
- thickened aortic wall and retroperitoneal fibrosis, often involving ureters as well - cause: autoimmune reaction to antigens in the aortic wall and also lymphatic blockage o
Aneurysms treatment:
- Stent grafts (metal grid mesh coated with solid material / fenestrated and branched stent grafts)
- Important to measure the diameter of aorta at level of renal arteries, pelvic vessels and length of proximal landing zone
treatment of stenosis ( example coarctation of aorta-congenital)/ ATS plaques
- PTA : percutaneous transluminal angioplasty
(balloon catheter introduced through a guidewire, the stenosis is dilated
o Endoleaks:
- Defined as persistent bleeding from the stent graft into the aneurysm sac
- Occur when stent grafts do not lie closely adjacent to aortic wall or have other weakness - CT diagnose it
Types:
Type 1: leaks in proximal or distal fixation site
Type 2: Based on retrograde inflow of blood from side branches
Type 3: Based on a defective point of intersection or an overlapping zone formed by individual portions of the stent graft
Type 4: Caused by diffuse porosity of the stent graft
Type 5: Leaks with no visible cause or demonstrable bleeding
- peripheral arterial occlusive disease:
- fontaine classification
- diagnostic techniques
- endovascular treatment
o PAOD (peripheral arterial occlusive disease )
- Is the result of atherosclerosis in the legs. The result is narrowing of the arteries in the lower extremities.
- Divided into acute limb ischemia and chronic limb ischemia, which is further divided into claudication and critical limb ischemia
- 30% of people age 70 and above
- Symptoms:
-about half are asymptomatic
- Typical symptoms:
-intermittent claudication, that is muscle pain after walking due to lack of blood supply to the muscles
- Less than 10% develop critical limb ischemia (rest pain and/or gangrene or ulceration) - Causes:
-same risk factors as general CVD
- Diagnosis:
-History, physical examination (the more proximal abnormal pulse, the more severe) - Ankle brachial index
- Doppler ultra-sound, CTA, MRA
o Treatment:
-Guidelines as to whether a stenosis or an obstruction should be treated by an interventional procedure or by open surgery with a bypass are provided by the TASC criteria
- TASC criteria is based on the prinsciple of length, size and amount of stenosis - Intervention is increasingly used as primary treatment
- Interventional treatment of stenosis and obstruction is performed through access in the groin, or more rarely in the brachial artery
- Frist step is to create a passage by means of a guidewire
- This methods used are:
a) PTA: percutaneous transluminal angioplasty – balloon catheter though guidewire. Stenosis dilated under manometric control
b) Stents: are metal grid meshes to bridge stenosis in vessels. A distinction is made between self-expanding stents and those which are dilated by means of a balloon catheter - Lesions are then dilated by the balloon techniques and/or treated with stents - The aim is to restore antegrade blood flow
o Fountaines classification:
- Stage 1 = Alteration of vessels, but symptoms only in case of severe loading - Stage 2 = Pain on weight-bearing (intermittent claudication)
a) pain-free walking distance > 200m
b) pain-free walking distance < 200m
- Stage 3 = Pain at rest, insufficient collateral circulation
- Stage 4 = Pain at rest and trophic disorders (necrosis/gangrene)
- pathological changes of renal arteries
o Introduction:
- Vascular diseases concern all renal vessels (arteriosclerosis, arteriolosclerosis) - More selectively the renal arteries
o Renovascular hypertension:
- Hypertension is of renovascular origin in a small percentage of cases (1-4%) - It is caused by a stenosis of the renal arteries.
- The occurrence of hypertension before the age of 20 years or suddenly after 50 years may be sign of renovascular hypertension
o Stenosis of renal artery:
- arteriosclerosis (90%)
- older patients
- fibromuscular dysplasia second most common cause (young women, all layers affected) - Investigated by non-invasive CTA or MRA
- Also duplex ultrasound in some cases
- DSA is mainly used as an interventional therapeutic procedure in renovascular hypertension, to dilate the stenosis by PTA for the purpose of stent implantation
o Treatment of stenosis in renal artery:
- Same way as those in peripheral arteries with PTA with/without stenting
- Indication are also the same with stenosis disrupting perfusion
- Stenosis in the renal artery may lead to therapy refractory renal hypertension and can be successfully treated by an interventional procedure
- Particularly in these vessels one uses adapted combinations of guidewire, catheters, balloons and stents
renal artery aneurysm
- 2nd most common visceral aneurysm ( after splenic artery)
- diagnosis : CTA
Treatment : stent placement / surgical repair ( ligation + bypass surgery)
- pathological changes of carotid arteries
o CAROTID STENOSIS
- Usually caused by an atherosclerotic process and is one of the major causes of stroke and TIA (transient ischemic attack)
- Atherosclerotic carotid arterial disease accounts for 15% of all ischemic strokes - Can result in wide-ranging stroke syndromes and TIA symptoms
- Carotid bulb and proximal segment of ICA most common
o Radiography:
- DSA replaced by US Doppler, CTA and MRA
- DSA for endovascular treatment
o Ultrasound
we can see thickening of intima
soft plaque : hypoechoic
hard plaque : hyperechoic ( w post shadowing )
- doppler: first choice for screening of carotid artery stenosis
flow :
- increased peak systolic velocity
- waveforms
biphasic : mild/moderate stenosis
monophasic : severe stenosis
absent : thrombosis
o Treatment:
- Carotid endarterectomy (CEA) : removal of atheromatous plaque material in the lining of artery
- carotid stenting
ANEURYSMS
neck pain , pulsatile mass, murmur
ATS - most common etiology
same as everywhere else
CAROTID DISSECTION
- separation of the layers of the carotid artery wall
most common cause of ischemic stroke in yound adults
causes :
- trauma / iatrogenic/ fibromuscular dysplasia
diagnosis :
- MRI T1W fat sat - intimal hemorrhage seen as high signal
treatment :
- pharmacological th( PTA +/- stent)
- pathological changes of intracranial arteries
ANEURYSMS
o Aneurysms: Cerebral aneurysms develop in the cource of one´s life and are therefore extremely rare in children. 3% of population has aneurysms. A typical manifestation of a bleeding aneurysm is subarachnoid hemorrhage.
The risk of a bleeding a. increased in proportion to the size. A fundus diameter < 7 mm in the anterior circulation is considered worthy of treatment only under certain conditions (the risk of hemorrhage per year is markedly below 3%). Mortality rate is 50% after hemorrhage.
o Imaging :
The gold standard is intraarterial DSA, but also MR angiography or CT angiography. MRA and CTA are suitable for screening with proven aneurysm.
Localization is typically at the branching sites of vessels, and most commonly found in the anterior communication artery
AVM (arteriovenous malformations)
o AVM: Is a short circuit between the arterial and venous leg of the vascular system, circumventing the capillary bed. It is a rare congenital abnormality and is found in only 0,14 – 1 % of any investigated population. The risk of hemorrhage is low, and intra-parenchymatous or subarachnoid hemorrhage may occur.
Imaging :
MRI is golden standard, but CTA or MRA may be additionally used. Managed by intraarterial DSA (interventional treatment), which is also a golden standard still for detection of AVM.
- T2-weighted (vessels with low signal intensity
because of rapid transport of stimulated protons). CT contrast – vessels absorbing the CM 🡪 visualized
o VENOUS HEMANGIOMA (cavernoma):
About 4% of investigation populations have a venous malformation, which is a formation of sinusoid vascular spaces or so-called cavernoma. Frequently occurs in number.
Location:
Are commonly found in cortical aspect of the cerebrum and the pons.
complications:
May trigger epilepsy and intraparenchymatous bleeding may occur.
Imaging :
CT: calcifications within the lesion are clearly seen
MRI is golden
T2-weighted (may be black and devoid of signals because of inward bleeding and hemosiderin deposits. BUT venous blood signal may be of high signal intensity, and margins black because of hemosiderin deposit)
- Deep venous thrombosis - May turner syndrome
- definition
- causes
- symptoms
- diagnostic techniques
- treatment
DVT
definition: formation of thrombus in a deep vein : most commonly the legs
- Basically all thromboses can be explained by the “Virchow triad”, i.e stasis, changes in blood, and the vessel wall
- Mechanism of its emergence is bases on many factors in combination with older age - Depending on progression, a distinction is made between:
- Ascending thrombosis (90%) of leg vein
- risk factors: age, obesity, immobilisation, earlier thrombosis, malignancies, surgery trauma, heart failure, hormones, birth - Descending thrombosis (10%)
- risk factors: surgery in the pelvis or hip, in rare cases by venous spurs
fun facts: the frequency of thrombosis in surgery without prophylaxis = 30-50%, without only 10%
o Imaging techniques and diagnosis:
- Colour doppler US
- venography (phlebography ) - contrast enhanced thrombus
o Clinical symptoms:
- Unilateral swelling of the leg
- Pain (tenderness to pressure in the calf)
- Discoloration (livid)
- Inexplicable dyspnea 🡪 pulmonary embolism
o Treatment:
- Thrombolytic, compression socks, anticoagulant therapy, reduce weight, mobility
o MAY TURNER SYNDROME
- refers to chronic compression of the left common iliac vein against the lumbar vertebrae - done by overlying right common iliac artery, with or without DVT
- Left has more transverse course and Is predisposed to compression
o Cause:
- The presence of a spur predisposes to development of DVT and differentiates this condition from bland DVT
compression causes blood stasis - which may lead to the formation of thrombi
- prolonged immobilization or pregnancy
o Symptoms:
- Unilateral (left) lower extremity edema and pain
o Radiography:
- CT (portal venous or venographic phase is used to assess site and extent of the compression point
- conventional venography with IVUS (intravascular US ): gold standard
o Treatment:
- Follow up is not necessary unless the patient is symptomatic from the process - Thrombolysis and stenting, removing clot and relives the compression to prevent recurrence
- Imaging techniques of lymphatic system
MR Lymphography
- use of superparamagnetic iron oxide particles (as cm)
- these particles normally taken up by macph of lymph nodes where they accumulate.
- in MTS lymph nodes, no significant contrast enhancement is seen in these nodes (macrophages replaced by tumour cells)
indication: detect nodal mts
lymphoscintigraphy :
- radioactive tracers(technetium) admn in skin, drains through the lymphatic system and imaged by a scintillation camera ( producing a 2d image of the lymphatic network.
lymphography :
- lymphatic contrast agent (direct blue/patent blue) admn in dermis , drained by associated lymphatic vessels on that site - this identifies lymphatic channels through which we can admn opaque cm for radiographic imaging.
Ultrasound :
most important primary investigation of enlarged superficial LN (cervical, axillary and inguinal)
- Purpose = distinguish enlarged reactive LN from malignant
- Distinguishing between bening and malignant LNs on US is based on following criterias:
1. Size > 1 cm (malignancy suspicion)
2. Shape: longitudinal versus transverse diameter < 2 (malignancy suspicion)
3. Absence of a hyperechoic hilum (suspicion of malignancy)
4. Displacement of the normal architecture of vessels (color duplex)
- CT (chest/abdomen) and MRI (cerebrospinal, leptomeningeal, skeleton and spine) are standard investigations for diagnosis and primary staging
- PET-CT is recommended for restaging during or after treatment as well as during follow-up
o Introduction: (lung/CHEST)
- Lymphatic vessels are not seen on the chest x-rays of healthy individuals
- The clinically important hilar lymph nodes are also not seen because of their small size - Pathologically enlarged hilar lymph nodes deform the hili
- CT is much more sensitive than the chest x-ray in imaging all thoracic lymph nodes
- Lymph nodes with a transverse diameter (short axis) of more than 1 cm are considered pathological
o Introduction: (lymph nodes of NECK)
- Lymph nodes are defense points embedded in the lymphatic pathway
- Easily accessed by ultrasound
- Normally spindle-shaped, hypoechoic with hyperechoic hilum
- May be enlarged due to reactive, inflammatory or neoplastic conditions
- Malignant lymph nodes are round, have irregular margins and loose hyperechoic hilum
- Malignant lymph nodes may be marked by central necrosis
- on CT and MRI, vital areas are strongly and heterogeneously stained with contrast medium - When all methods and criteria are combined, lymph node MTS can be identified with accuracy of 90%
- Benign causes: bacteria, viral, mononucleosis, borreliosis, tularemia, TB, sarcoidosis, histiocytosis
- arteriography ( DSA, CTA, MRA) + vascular ultrasound pathologies
Stenosis (Picture):
Congenital: coarctation of aorta (localized), hypoplasia of arteries (diffused)
Acquired: dislocation, uneven contours, ATS, intramural hematoma
Vascular US
Stenosis:
Peak systolic velocity: increased (normal: <125cm/sec)
Presence of plaque or intimal thickening.
Additional criteria: ICA/CCA PSV ratio <2.0 and ICA EDV <40cm/sec
Waveform:
Triphasic: normal
Biphasic: mild-moderate stenosis
Monophasic: severe-stenosis, thrombosis
Absent: thrombosis.
Turbulent flow behind the stenosis
The higher flow acceleration = the higher degree of stenosis.
Occlusion:
No detectable patent lumen or flow
There may be compensatory increased velocity in the contralateral artery (Eks: Carotid)
Atherosclerosis:
Thickening of intima - shape (irregular or regular)
Soft plaque: hypoechoic
Hard plaque (calcification) hyperechoic with post. shadowing
Greater degree of calcification in a plaque the harder it is.
Thrombus detection:
DVT – emergency US
Aneurysm:
Preferred choice for monitoring of small aneurysms.
B-mode: expansion of the vessel wall (measure the size), mural thrombi
Doppler: spiral turbulent flow in the bag, shuttle flow in the neck.
AVM:
Heterogenous lesions with large vessels and multiple sites of pulsatile AV shunting. “coloric mosaic pattern”
Dissection: Dissection flap clearly visible
- subclavian steal syndrom
o Introduction:
- is a specific and typical disease caused by a stenosis of the left subclavian artery proximal (close to aorta) to the site of departure of the vertebral artery
- This may cause a reversal of blood flow in the vertebral artery
- Leads to vertebrobasilar insufficiency
- symptoms: dizziness, impaired vision, ataxia, impaired circulation in upper extremities, dysarthria, weakness/sensory disturbances, weak or absent pulse, decreased BP - marked cerebral or brachial symptoms require treatment
o Causes:
- Atherosclerosis (95%)
- M:F ratio of 2:1, L:R ratio of 3:1
- Vasculitis
- Thoracic aortic dissection
- Congenital interrupted aortic arch
o Diagnosis:
- Ultrasound (retrograde flow in ipsilateral vertebral artery)
- CT (stenosis easily identified)
- MR (stenosis easily identified)
- DSA (performed at time of endovascular intervention)
o Treatment:
- PTA +/- stenting
- Surgical bypass surgery
- imaging techniques of veins
o Introduction:
- Various methods are available for diagnostic imaging of the venous system. These are used differently in various organs:
1. Phlebography = x-ray with visualisation with contrast medium
2. Ultrasonography including colour-duplex ultrasound (=B-mode image + Doppler+colour)
3. CT/MRI - Study anatomy on picture on page 534 in book ;)
o Ascending phlebography:
- Investigation on the fluoroscopy table (45 degree tilting)
- Compression bandage above the ankle
- Injection of 50 to 70 ml of contrast medium into a vein of the big toe
- Fluoroscopy-guided images in several planes
- In case of thrombosis 5000 IU heparin/NaCL i.v
- The risk of thrombosis due to CM is < 1 promille
- Indications: thrombosis (post-thrombotic syndrome),
Varicosity
- Criteria for thrombosis: Contrast medium recesses: recent thromboses arise due to stasis in the valve region and are bathed in contrast medium, no veins are depicted because of thrombotic obstruction, collateral circulation
o Doppler ultrasound:
- Used as first investigation
- Images thrombi in the deep veins (pelvic veins, superior femoral vein, popliteal vein) - 🡪 in more than 90%, but 50-80% in veins of lower leg
- In many instances, thrombi in the muscle veins of the calf are only seen on ultrasonography and may escape detection on phlebography
- Criteria for thrombosis: increase in vessel diameter + absence of compressibility when pressure is exerted with the transducer
- Recent thromboses are hypoechoic and difficult to differentiate from flowing blood - Older thromboses turn increasingly hyperechoic due to connective tissue
