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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3627_Библиотеки_им_академика_М_И_Перельмана
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192
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RadCases.thieme.com RadCases Interventional Radiology
■
Imaging Findings
A, B C, D
(A) Contrast-enhanced CT shows the superior mesenteric artery (SMA) to be patent (arrow) at the level of the left renal vein. (B) A more caudal slice shows
a near-occlusive thrombus (arrow) lling the lumen of the SMA. (C, D) The small bowel is diusely dilated, and pneumatosis (arrows) is seen within the
wall of the transverse colon.
■ Dierential Diagnosis
• Acute mesenteric ischemia caused by arterial thrombosis.
■ Essential Facts
• Acute arterial mesenteric ischemia (AAMI) is caused
by thromboembolism from a more proximal source,
thrombosis of a primary arterial condition, or much less
commonly, nonocclusive mesenteric ischemia (NOMI).
• Causes of thrombosis include atherosclerosis (especially
ulcerated), traumatic injury/dissection, segmental arterial
mediolysis, bromuscular dysplasia, or Takayasu’s arteritis
as well as systemic conditions such as hypercoagulable
states and hypotension.
• Origins of thromboembolism include the heart
(myocardial infarction, bacterial endocarditis, atrial
brillation), arterial plaque or aneurysm, and surgical or
endovascular procedures.
• Presentation is rapid progression (hours to days) of
abdominal pain resulting from acute onset of insucient
oxygen supply to the bowel. Nonspecic ndings of
nausea, vomiting, fever, and low-grade gastrointestinal
bleeding may be present. Severe metabolic acidosis is a
grave indicator of critical bowel ischemia.
• Imaging considerations:
◦ CT angiography and multiphase CT are rst-line tests
for suspected AAMI. Look for bowel dilatation, bowel
wall thinning, fat stranding, pneumatosis, portal
venous gas, pneumoperitoneum and arterial stenosis,
thrombosis, or occlusion.
◦ Mesenteric angiography is sometimes performed for
diagnosis and surgical planning but usually to guide
surgical or endovascular treatment. Signs of thrombotic
AAMI include abrupt arterial cuto and thrombus.
◦ Arterial thrombosis typically involves the origin of the
aected mesenteric artery resulting in ischemia to a
larger distribution of bowel.
◦ Arterial thromboembolism typically involves the distal
branches of a mesenteric artery such as the terminal
ileal and ileocolic branches of the superior mesenteric
artery resulting in a more focal region of ischemia.
• Treatment considerations:
◦ Most patients with peritoneal signs and pneumatosis
undergo emergent laparotomy due to rapid (, 12 hours)
progression to ischemic bowel. Revascularization of
nonviable bowel is contraindicated.
◦ Cases involving pneumatosis and portal venous gas
typically require surgical resection of bowel combined
with aortomesenteric bypass.
◦ Endovascular thrombolysis and suction thrombectomy
have been applied to occlusive AAMI, particularly for poor
surgical candidates, cases with slow clinical progression,
and cases without peritoneal signs. The typical regimen is
intra-arterial infusion of tissue plasminogen activator at
1 mg/h with subclinical or no heparin infusion.
◦ Stent placement may be used after thrombolysis for
acute on chronic obstruction. Balloon-expandable
stents are placed for their superior hoop strength.
ü Pearls and û Pitfalls
8û AAMI should not be confused with mesenteric
venous thrombosis (MVT), which can be acutely
progressive with similar clinical signs and mortality
rates. Thickened (rather than thinned) bowel wall
with reduced attenuation, fat stranding, and superior
mesenteric vein thrombosis are imaging ndings.
MVT more typically progresses over weeks.
8û Occlusive AAMI should not be confused with NOMI,
which is caused by vasopressors, shock of any
etiology, and cardiopulmonary bypass resulting in a
diuse reduction of mesenteric arterial blood ow.
Arterial-phase CT shows poor distal mesenteric blood
ow, diminutive arterial branches, and when severe,
diusely ischemic bowel. Treatment is intra-arterial
infusion of a vasodilator (papaverine).
8û Pneumatosis and portal venous gas are not always signs of
ischemia! Gas-producing bacteria colonize necrotic bowel
in cases of ischemia, but other causes include severe
infection, radiation therapy, and intestinal obstruction.
8û Do not confuse portal venous gas (travels to the periphery
of the liver) with biliary gas (avoids the periphery).
Case 97
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A B
193
■ Clinical Presentation
A 65-year-old man presents with increasing postprandial abdominal pain.
■ Further Work-up
C D
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RadCases.thieme.com RadCases Interventional Radiology
■
Imaging Findings
C D E F
(A) CT arteriography with 3D reformatting shows atherosclerotic disease of the abdominal aorta and its branches. Stenosis and dense calcications are
seen at or near the ostia of the celiac, superior mesenteric, and inferior mesenteric arteries. (B) Doppler ultrasound of the proximal SMA shows marked
increase in systolic ow velocity to 454 cm/s (normal velocity is , 200 cm/s. Images A, B appear on previous page. (C) Selective SMA angiogram shows
marked ostial stenosis (arrow). (D) Selective IMA angiogram shows marked ostial stenosis (arrow). (E) Resolution of the CA stenosis is seen after stent
placement (arrow). (F) Resolution of the SMA stenosis is seen after stent placement (arrow).
■ Dierential Diagnosis
• Chronic mesenteric ischemia caused by arterial stenosis.
■ Essential Facts
• Chronic arterial mesenteric ischemia (CAMI) is usually
caused by atherosclerosis, but other etiologies include
retroperitoneal brosis, median arcuate ligament
syndrome (MALS), bromuscular dysplasia (FD), segmental
arterial mediolysis (SAM), and Takayasu’s arteritis (TA).
CAMI can progress to acute arterial mesenteric ischemia
(AAMI) if complicated by thrombosis or thromboembolism.
• CAMI is typically symptomatic if obstruction involves
at least two primary mesenteric arteries. The typical
presentation is slowly progressive postprandial
abdominal pain accompanied by weight loss.
• Imaging considerations:
◦ Doppler ultrasound is an excellent screening test for
CAMI. Positive ndings include elevated systolic velocity
(. 200 cm/s) and grayscale demonstration of ndings
such as occlusion, obstruction, or post-stenotic dilation.
Flow in some arterial segments may be reversed
because of collateral supply.
◦ CT arteriography and multiphase CT are rst-line tests
for suspected CAMI with the initial goal of distinguishing
between broad types of mesenteric ischemia: CAMI,
AAMI, nonocclusive mesenteric ischemia (NOMI), and
mesenteric venous thrombosis (MVT).
◦ CT of CAMI may show bowel dilatation, arterial
stenosis/occlusion, and enlarged collateral arteries.
Signs of MVT and AAMI should be excluded, which
include bowel wall thickening (MVT) or thinning
(AAMI), thrombosis, fat stranding, pneumatosis, portal
venous gas, and pneumoperitoneum.
◦ Conventional angiography of CAMI is typically performed
with the intent to treat obstructions, and it provides the
best demonstration of collateral supply, slow ow, and
reversal of ow caused by arterial obstruction.
◦ Celiac artery (CA) obstruction usually results in
collateral supply to CA branches from the superior
mesenteric artery (SMA) via the pancreaticoduodenal
arcade or the arc of Buehler (anomalous direct
connection from CA to SMA).
◦ SMA obstruction usually results in collateral supply to
SMA branches from the CA via the pancreaticoduodenal
arcade or the arc of Buehler, as well as collateral supply
from the inferior mesenteric artery (IMA) via the marginal
artery of Drummond or an arc of Riolan (anomalous
direction connection from the left to middle colic artery).
◦ IMA obstruction usually results in collateral supply
to IMA branches from SMA via the left colic and the
marginal artery or an arc of Riolan, as well as collateral
supply from the internal iliac artery via retrograde ow
in the superior rectal artery.
• Treatment considerations:
◦ The high-risk patient population often elevates
endovascular options to rst-line over surgical options.
◦ Endovascular management of conditions such as FD and
burned-out TA may involve a trial of angioplasty alone.
◦ Endovascular treatment of atherosclerotic CAMI consists
of stent placement. Balloon-expandable stents are
preferred because lesions are usually ostial (like renal
stenosis), calcied, and require high hoop strength.
◦ Surgical options for CAMI include aortomesenteric bypass
or reimplantation of the obstructed mesenteric artery.
ü Pearls and û Pitfalls
8û Endovascular treatment of active TA is contraindicated;
treat active TA with steroids to resolution rst.
8û Endovascular treatment of MALS is contraindicated
prior to ligament release surgery; patients with
persistent xed stenosis after release are candidates.
8û Revascularization of nonviable bowel is contraindicated.
Cases involving pneumatosis and portal venous
gas require surgical resection combined with
aortomesenteric bypass.
Case 98
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195
A B
■ Clinical Presentation
A 45-year-old man with urothelial cancer presents with acute onset of bilateral, lower extremity swelling after caval lter
placement.
■ Further Work-up
C, D, E
196
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RadCases.thieme.com RadCases Interventional Radiology
■
Imaging Findings
A, B
(A) Coronal-reformatted, contrast-enhanced CT shows complete obstruction of the inferior vena cava (IVC) by thrombus (arrows) both cranial and caudal
to the lter. A displaced double-J ureteral stent is seen in the right ureter. (B) Conventional IVC venography performed from a jugular approach shows
complete IVC occlusion at the iliac conuence (arrow) and venous drainage via developing ascending lumbar collaterals (arrowhead). (C) A suprarenal IVC
lter (large arrow) was placed above the thrombosed infrarenal lter (small arrow). A suction thrombectomy catheter (arrowhead) was placed in the
distal IVC. (D) The caval thrombus was completely removed above and below the lter. (E) The preexisting infrarenal lter was removed (small arrow), and
the suprarenal lter was left in place (large arrow).
■ Dierential Diagnosis
• Acute inferior vena cava thrombosis resulting from an
indwelling lter.
■ Essential Facts
• Acute inferior vena cava (IVC) thrombosis most
commonly results from extension of lower extremity
deep venous thrombosis (DVT) or from iatrogenic
causes such as indwelling IVC lters, permacaths
placed via femoral venous or direct caval puncture,
femoral arteriovenous hemodialysis grafts, and caval
anastomoses (e.g., for liver transplantation).
• Other causes include retroperitoneal brosis, local
infection, and extrinsic compression or ingrowth by
tumor or lymphadenopathy.
• Clinical presentation depends on the time course of
thrombosis versus development of venous collaterals,
which include the ascending lumbar, azygous,
hemiazygous, lumbar, and epigastric veins.
• Symptoms range from asymptomatic, to leg swelling,
to calf ulceration, to frank phlegmasia cerulea
dolens—compartment syndrome resulting from venous
transudate that compromises arterial ow.
• Postthrombotic syndrome (PTS) may develop years
after DVT and occurs in . 50% of patients with
lower extremity DVT. Symptoms include edema, skin
hyperpigmentation, pain, and skin ulceration.
• Treatment considerations for DVT:
◦ In most cases of DVT, patients are bridged from
heparin to warfarin to prevent propagation of
thrombus and the potential for pulmonary artery
thromboembolism (PE).
◦ Indications for therapeutic intervention vary but include
caval preservation for dialysis access, lter removal,
transplant graft survival (pancreatic, renal, and liver),
and preservation of future transplantation options.
◦ Intervention is often performed in younger and
more active patients with DVT to prevent PTS.
Revascularization reduces, but does not eliminate,
the risk of PTS.
◦ Options are almost exclusively endovascular.
◦ Catheter-directed thrombolysis can be performed from
a femoral or jugular venous approach. In most cases,
extended infusions of recombinant tissue plasminogen
activator (r-tPA) through a multi-sidehole catheter
are required (24–36 hours), typically performed at a
rate of 0.5 mg/h with subclinical (, 500 mL/h) or no
concurrent heparin infusion.
◦ Ultrasound-stimulated thrombolysis systems have
been used to successfully lower the duration of
treatment.
◦ Mechanical thrombectomy is routinely used for
iliocaval thrombosis and results in marked reduction in
treatment times. In some cases, clearance of complete
caval obstruction is achieved in a single session, and
in most cases, clearance is achieved with adjunctive
thrombolysis over a period that is , 24 hours.
◦ In cases of thrombolysis and thrombectomy of the IVC,
adjunctive balloon angioplasty and/or self-expanding
stent placement is often necessary.
Pearls and Pitfalls
IVC lters can be removed by standard methods
without thrombectomy/thrombolysis if the indwelling
thrombus occupies , 20% of the interior lter volume.
PE can complicate caval thrombectomy and
thrombolysis, but the reported incidence of iatrogenic
PE in this setting is quite variable (ranging from 0 to
20%). Therefore, placement of an IVC lter above the
renal veins during caval thrombolysis or thrombectomy
is a subject of debate in the literature.
Surgical thrombectomy and fasciotomy of the
extremities and IVC may be required for rapidly
progressive phlegmasia cerulea dolens.
Therapeutic heparinization during thrombolysis with
r-tPA is avoided because of a high risk of associated
bleeding complications.
C, D, E
Case 99
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197
A
■ Clinical Presentation
A 37-year-old woman presents with acute-onset left ank pain and syncope.
■ Further Work-up
B C
RadCases.thieme.com RadCases Interventional Radiology
https://t.me/med1917
198
■
Imaging Findings
A B C D
(A) Contrast-enhanced CT shows a left renal parenchymal defect (arrow), an adjacent mass containing fat (arrowhead), and surrounding hemorrhage.
(B) Renal arteriogram shows the parenchymal defect (arrow) and enlarged, tortuous upper pole branch with aneurysms (arrowhead) extending into the
mass. No arteriovenous shunting. (C) Venous-phase scan shows active hemorrhage or pseudoaneurysm (arrow). (D) The abnormal branch was embolized
with coils after the angiomyolipoma was embolized with particles.
■ Dierential Diagnosis
• Angiomyolipoma (AML): Indicated by hypervascularity
with tortuous, dilated aneurysmal arteries extending
into a fat-containing renal mass and the absence of
arteriovenous shunting.
• Perirenal liposarcoma: Not usually associated with a renal
parenchymal defect or a tumoral vessel extending to the
renal cortex.
■ Essential Facts
• Angiomyolipomas (AMLs) are benign hamartomas
containing fat, smooth muscle, and vascular tissue.
They represent , 3% of renal masses.
• Approximately 70% of AMLs are sporadic (typically
unilateral and solitary).
• Approximately 80% of tuberous sclerosis patients have
AMLs (typically bilateral).
• Imaging considerations:
◦ CT scan showing macroscopic fat in a renal mass is
virtually diagnostic of AML. CT scanning also measures
size of AMLs and the presence of hemorrhage, which
determine the need for treatment.
◦ In exophytic cases like this one, AML is suggested
by a tumoral vessel extending to the renal cortex and
a parenchymal defect at this site of contact with the
mass.
◦ Conventional renal angiography is performed with
intent to embolize. Active extravasation is rare, but
embolization of feeders is still performed. Findings
include tumor vascularity, ectatic vessels, and
aneurysms.
• Treatment options:
◦ Embolization is performed for life-threatening
bleeding, pain, or symptoms of mass eect. Recurrence
aects 30% of patients, often occurring years after
embolization.
◦ AMLs . 4 cm are prophylactically embolized because
90% are symptomatic and 50% bleed.
◦ Nephron-sparing surgery may replace embolization in
cases of severe, life-threatening bleeding.
Pearls and Pitfalls
Superselective catheterization of arterial feeders is
performed (microcatheter if necessary).
Alcohol or particles (polyvinyl alcohol or gel spheres)
are preferred agents. Coils are added to treat
aneurysms. If injecting alcohol, maintain arterial stasis
with a balloon occlusion catheter to avoid nontarget
sclerotherapy.
Arteriovenous shunting is typically absent for benign
tumors of the kidney. Therefore, particle embolization
is usually a rst-line option.
Complications include nontarget embolization,
reduction of renal function (although risk may be worse
with surgical resection), and arterial injury.
Liposarcoma would be suggested by calcications in the
mass and no parenchymal defect.
Case 100
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199
A
■ Clinical Presentation
A 76-year-old woman presents with a multi-year history of recurrent pneumonia and chest pain.
■ Further Work-up
B C
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RadCases.thieme.com RadCases Interventional Radiology
■
Imaging Findings
A B,C
(A) CT scan shows a left lower lobe mass that appears inhomogeneous with solid components, cysts, and emphysema (arrow) in the adjacent lung.
(B) Conventional angiogram shows a large systemic arterial feeder (arrow) to the mass, arising from the aorta. (C) Capillary-phase image shows various
abnormal vessels within the mass (arrow), some of them enlarged and tortuous. (D) Venous-phase image shows pulmonary venous drainage (arrow).
(E) The patient was a poor surgical risk for resection, and embolization was performed with coils (arrow). Particles were avoided because of rapid arterio-
venous shunting and the associated risk of paradoxical systemic arterial embolization.
■ Dierential Diagnosis
• Intralobar pulmonary sequestration: Strongly suggested
by a left lower lobe structure with systemic artery supply
and pulmonary venous drainage.
• Arteriovenous shunting: Possible when caused by prior
infection, especially given signs of recurrent infection
such as bronchiectasis. Unlikely within a pulmonary
neoplasm, given the imaging appearance and chronicity.
Such shunting occurs in approximately one third of
primary lung malignancies.
• Congenital arteriovenous malformation (AVM): Unlikely.
Nearly all pulmonary AVMs have pulmonary arterial and
venous drainage.
■ Essential Facts
• Sequestration is likely an abnormality of foregut
development during the rst 2 months of embryogenesis,
resulting in a separate lung bud supplied by anomalous
systemic arteries and lacking normal bronchial
communication.
• Intralobar sequestrations (ILS) lack a separate pleural
membrane and are more common than extralobar
sequestrations (ELS). ILS occurs on the left in 60% of cases:
Venous drainage happens via the pulmonary veins in
95% of cases.
ILS has no sexual predominance and presents later
in life compared to ELS, due to the near absence of
associated congenital anomalies.
Symptoms are related to chronic pulmonary infections,
high-output cardiac failure, and bleeding.
• Extralobar sequestrations have a separate pleural
membrane, most commonly occur on the left between
the lung and diaphragm, and may occur in the chest,
diaphragm, and abdomen.
Venous drainage occurs via the systemic veins in 75% of
cases (25% with some pulmonary venous drainage).
ELS is more common in males and usually presents in
the rst 6 months due to associated anomalies.
Symptoms may be respiratory, gastrointestinal,
and/or cardiac due to hypoplastic lung, congenital
lobar emphysema, congenital cystic adenomatoid
malformation, bronchogenic cyst, diaphragmatic hernia
(most common association), enteric duplication cysts,
total anomalous pulmonary venous return, truncus
arteriosus, dextrocardia, and pericardial defects.
• Imaging ndings:
Plain radiograph may show a subtle opacity, often left
lower lobe, and often partially obscured by the cardiac
silhouette. For ELS, look for associated anomalies and
azygous enlargement due to anomalous systemic
venous drainage.
Multidetector CT angiography or MRI/MR angiography
may show a homogeneous or inhomogeneous mass, a
solid component mimicking neoplasm, cysts with air
and uid, and emphysema in the adjacent lung. For ELS,
look for associated anomalies and azygous enlargement.
Conventional angiography shows systemic arterial
supply to dense focal blush. Venous drainage usually
distinguishes ELS from ILS.
Pearls and Pitfalls
Treatment of complicated sequestrations is usually
surgical resection, although embolization has been
described, particularly for poor surgical candidates.
Asymptomatic untreated sequestrations can lead to
respiratory infections, gastroesophageal reux, and
asthma, emphasizing the need for follow-up. Some
investigators advocate treatment.
The anomalous vascularity of sequestrations may be
confused with chronic inammatory changes, AVMs, or
neoplasms.
Complications of embolization have included pain and
pleural eusion.
D, E
Case Questions and Answers
https://t.me/med1917
The questions and answers in the following section are numbered as cases 1 through 100. The questions correspond to the
respectively numbered case reviews and are intended to be answered after working through the cases.
201
■ Case 1
1. The treatment of choice for adventitial cystic disease is
which of the following?
a) Surgery
b) Urgent lytic therapy
c) Stent placement
d) In fact, no therapy is required.
The correct answer is (a), because the management is
surgical. Aspiration is not useful because it has been
described to be associated with a high recurrence rate of
the cystic lesions. Doppler ultrasound and MRI are the
imaging methods of choice to conrm the diagnosis and
demonstrate the cysts and the anatomic relationship with
the popliteal arteries.
2. The best imaging modality to make the diagnosis of
cystic adventitial disease is…
a) Angiography
b) CT scan
c) Ultrasound
d) Positron emission tomography scan
e) MRI
The correct answer is (e). MRI is the best imaging study
to make this diagnosis. The perivascular cysts are well depicted with MRI. Ultrasound may be useful, but it may be
dicult to demonstrate the cysts. Angiography will show
only the wall irregularity in the wall of the arteries.
2. Regarding removable or optional IVC lters, the best
imaging method to identify a fractured lter is which
of the following?
a) Noncontrast CT scan
b) Contrast-enhanced CT scan
c) MRI
d) Kidney, ureter, and bladder radiograph
The correct answer is (d). A kidney, ureter, and bladder
(KUB) radiograph, although a very simple test, gives great
detail on the status of the IVC lter. One of the most important details to investigate in an IVC lter that has a long-
term indwelling time is to look for fractures. The KUB is an
excellent imaging modality to identify lter fractures.
■ Case 3
1. Described complications of percutaneous, image-guided
bone biopsies include all of the following except…
a) Infection
b) Fracture
c) Bleeding
d) Tumor seeding
e) Severe pain
The correct answer is (d). Tumor seeding is not a described
complication of percutaneous bone biopsy. The complica-
tion rate of image-guided bone biopsy is as low as 1%. Open
biopsy has a complication rate of 16%. All other options
are described complications of image-guided bone biopsy.
■ Case 2
1. The optimal time for inferior vena cava (IVC) lter
removal is which of the following?
a) Always within 2 weeks
b) The longer the indwelling time, the easier the
removable lters are to take out.
c) Each lter model has its optimal retrieval window.
d) Filter removal after recommended manufacturer’s
optimal window is contraindicated.
The correct answer is (c) because each IVC lter has a
recommended manufacturer optimal removal window
time. However, IVC lters can be removed even after the
recommended optimal window time.
2. Regarding the diagnostic yield of bone biopsies, which
of the following statements is false?
a) Target selection is crucial to success.
b) Needle pathway should be carefully evaluated.
c) The presence of a pathologist during the procedure
increases the diagnostic yield.
d) MRI is superior to positron emission tomography
(PET) scan in directing to the site of highest suspicion.
e) Areas of necrosis should be avoided.
The correct answer is (d). Despite the high sensitivity of
MRI for the diagnosis of bone metastases, the specicity is
variable. Selecting as a target area those with greater metabolic activity at PET/CT increases the diagnostic yield of a
malignant process. PET is easier to interpret and is superior
to MRI in guiding to the most likely target of positivity.
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