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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3886_Библиотеки_им_академика_М_И_Перельмана
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160
RadCases Interventional Radiology
■
Diff erential Diagnosis
• Type 2 endoleak
■
Essential Facts
• In patients with stent-grafts, an endoleak occurs when
blood fl ow persists outside the graft but in the aneurysm
sac or communicating artery leading to arterial pressure in
the sac and increased risk for expansion and rupture.
• In this case, because the rate of contrast leakage is low
(at the level of the bifurcation of the graft), anterior, and
remote from the graft itself, type 2 endoleak from the IMA
is most likely.
• Because the leakage is remote from the modular connec-
tion, the ends of the graft, or the middle of the graft, types
1, 3, and 4 are unlikely.
• The incidence of type 2 endoleak is 10 to 20%.
• Risk factors for type 2 endoleak include mural thrombus
and a higher number of aortic arterial branches.
• Classifi cation of endoleaks:
1. Leak at attachment site
2. Branch leak
3. Graft defect
4. Graft fabric porosity
5. Endotension (no endoleak or sealed endoleak)
• Treatment of endoleaks:
1. Angioplasty, stent, or endograft
2. Follow with serial imaging. Many seal spontaneously
without sequelae. Alternatively, treat with embolization
of the feeding artery, embolization of the sac, or laparo-
scopic clipping of the feeding artery.
■
Other Imaging Findings
• Triphasic computed tomographic angiography is the
modality of choice for the identifi cation of endoleaks and
serial follow-up to measure the aneurysm size and detect
complications. The three phases are nonenhanced (to dis-
tinguish calcifi cations from leaks), arterially weighted, and
delayed (to detect leaks that slowly perfuse the sac).
• Conventional angiography is usually performed with the
intent to embolize the feeding artery and sac.
✔ Pearls & ✘ Pitfalls
✔
Type 2 endoleaks are typically supplied by retrograde
fl ow from the IMA, lumbar arteries, middle sacral arter-
ies, and/or accessory renal arteries.
✔ Type 2 endoleaks in which the sac is supplied by a single
vessel may spontaneously regress. Supply by multiple
vessels requires treatment.
✔ Delayed type 2 endoleaks (e.g., seen on 6-month follow-
up CT) require treatment.
✔ Embolization is typically performed via either transarte-
rial or direct translumbar puncture to gain access into
the sac and into as many collateral arteries as possible.
✔ Embolic agents are usually coils and/or glue.
✔ Other complications of aortic stent-graft placement
include graft migration and thrombosis.
✘ Embolization of collateral vessels alone tends to result in
recurrence. Embolization of the aneurysm sac and col-
lateral vessels minimizes the risk for recurrence.
Axial image shows contrast leakage (arrow) into the anterior aneurysm sac at the level of the inferior
mesenteric artery .
3. Endograft
4. None. They typically seal spontaneously. If the aneu-
rysm continues to enlarge, repair surgically or place a
new endograft.
Case images: Frontal and lateral three-dimensional (3D) volume-rendered computed to-
mographic angiograms (CTAs) show a large infrarenal AAA extending to the iliac bifurca-
tion. The axial source image most accurately refl ects the true diameter of 8 cm. Frontal
and lateral 3D volume-rendered CTAs show interval placement of an aortic endograft.
BCDE
A
■
Imaging Findings
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161
Case 81
A
B
C
■
Clinical Presentation
The patient is a 57-year-old woman with passage of bright red blood per rectum.
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162
RadCases Interventional Radiology
■
Imaging Findings
AB C D
(A) Selected technetium Tc 99m tagged red blood cell (RBC) study shows
mobile radioactive tracer in the right hemiabdomen ( arrow ). (B) Selected
superior mesenteric angiogram shows extravasation in the right lower
quadrant ( arrow ). (C) Superselected ileocolic branch angiogram with use
of a microcatheter. (D) Successful embolization of two cecal branches with
microcoils.
■
Diff erential Diagnosis
• Colonic hemorrhage
■
Essential Facts
• Common causes are diverticulosis, neoplasia, and angio-
dysplasia.
• Colonoscopy may be used to diagnose and treat bleeding
in acute cases but requires adequate bowel preparation.
In many cases, diagnosis and treatment are performed by
radiologists.
• A tagged RBC scan is performed to localize and verify ac-
tive bleeding. Its sensitivity is better than that of angiogra-
phy because the bleeding may be slow or intermittent, and
the scans are performed continuously over hours.
• Angiography and embolization should be carried out
within 1 hour if the RBC scan result is positive.
• Superselective embolization (with a microcatheter) is the
primary treatment option. The marginal artery or terminal
vasa recta may be embolized.
• Embolic agents used include (most commonly) microcoils and
Gelfoam. Particles are sometimes used for angiodysplasia.
■
Other Imaging Findings
• Multidetector computed tomographic angiography may
replace tagged RBC scan to screen patients for active
bleeding.
• All patients with lower gastrointestinal (GI) bleeding
should eventually undergo colonoscopy to determine the
underlying cause.
✔ Pearls & ✘ Pitfalls
✔
Medical treatment resolves most cases of lower GI
bleeding—correction of coagulopathy, fl uid resuscitation,
transfusion of blood products.
✔ Immediate angiography, with omission of the tagged
RBC study, may be necessary in the setting of very brisk
bleeding.
✔ Infusion of vasopressin into the mesenteric or celiac
artery has largely fallen out of favor because of the isch-
emic complications and prolonged treatment time. Proto-
col: 0.2 U/h, increase to 0.4 U/h if unsuccessful, taper over
12 to 24 hours if successful.
✘ Risk for ischemia from superselective colonic emboliza-
tion is < 5%.
✘ Right-sided colonic bleeding is less responsive to em-
bolization than left-sided colonic bleeding. This is likely
caused by a preponderance of angiodysplasia in the right
side of the colon, which is less responsive to emboliza-
tion than predominantly left-sided diverticulosis.
✘ Patients with multifocal disorders such as diverticulosis
are at increased risk for recurrent bleeding from other
sites.
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163
Case 82
A B
C
■
Clinical Presentation
A 46-year-old man presents to the emergency department with fever, nausea, vomiting, and back pain. The image in Figure A
was obtained on the day of admission. The images in Figures B and C were obtained 4 weeks later.
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164
RadCases Interventional Radiology
■
Imaging Findings
ABC
(A) Infused computed tomographic (CT) scan shows fl uid collection ( ar-
rows ), fat stranding, and an enlarged pancreas, consistent with acute fl uid
collection of pancreatitis. (B) Image obtained 4 weeks later shows enlarg-
ing, painful pseudocyst with a well-defi ned, enhancing wall ( arrows ). (C) A
percutaneous drain was placed.
■
Diff erential Diagnosis
• Pancreatic pseudocyst: Indicated by development of a
walled-off pancreatic collection in 4 weeks.
• Pancreatic phlegmon: Presents as a swollen, infl amed
pancreas.
• Pancreatic abscess: May be indistinguishable from a
pseudocyst.
■
Essential Facts
• Pancreatic fl uid collections occurring within the fi rst 4
weeks of pancreatitis include acute fl uid collections, pan-
creatic phlegmon and necrosis, and pancreatic abscess.
• Pancreatic fl uid collections occurring after 4 weeks include
abscesses and pseudocysts.
• Acute pancreatic fl uid collections of pancreatitis have no
well-defi ned wall on CT (Fig. A) and typically resolve spon-
taneously. Needle aspiration may become necessary.
• The term pancreatic phlegmon and necrosis describes an
enhancing, swollen, infl amed pancreas on CT scan. Catheter
drainage usually fails because of a high level of viscosity.
• Pancreatic abscesses have a high mortality rate, so emer-
gent drainage is indicated.
• Pseudocysts have a well-defi ned wall and contain a mix-
ture of autodigested tissue, pancreatic fl uid, and blood.
• Simple pseudocysts commonly resolve without drainage.
• Complicated pseudocysts cause pain, bleeding, or in-
fection, exhibit increased size (> 5 cm) and continuing
enlargement, and require drainage.
• Treatment options for pseudocysts include percutaneous
drainage, endoscopic cyst-gastrostomy, and surgical cyst-
enterostomy.
• Percutaneous routes of drainage are transperitoneal, retro-
peritoneal, and transgastric.
■
Other Imaging Finding
• Magnetic resonance cholangiopancreatography or endo-
scopic retrograde cholangiopancreatography is sometimes
performed to evaluate duct patency and duct–cyst commu-
nication to determine the appropriate treatment of pseudo-
cysts—surgical, endoscopic, or percutaneous drainage.
✔ Pearls & ✘ Pitfalls
✔
The duration of percutaneous drainage of pseudocysts is
shortest when the cyst does not communicate with the
pancreatic duct.
✔ In cases of cyst–duct communication, stenosis or ob-
struction of the duct markedly increases the duration of
drainage. Many prefer surgical or endoscopic drainage in
these cases.
✔ For pancreatic abscesses, both percutaneous and endo-
scopic catheter drainage are viable options.
✘ Percutaneous drainage of sterile, acute fl uid collections
or simple pseudocysts should be avoided if possible
because of the risk for superinfection.
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165
Case 83
■
Clinical Presentation
A 42-year-old patient presents with hypertension refractory to medical management.
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166
RadCases Interventional Radiology
■
Imaging Findings
Conventional aortography shows beading of the right renal artery
( arrow ), indicating fi bromuscular dysplasia (FMD).
■
Diff erential Diagnosis
• Renal fi bromuscular dysplasia (FMD): Indicated by bead-
ing of the renal artery sparing the medial third.
• Atherosclerosis: Unlikely in a young adult with minimal
arterial fi ndings visible elsewhere.
■
Essential Facts
• FMD is a rare, noninfl ammatory disease of unknown etiol-
ogy described in persons of all ages but most commonly in
women (4:1) 30 to 50 years of age.
• Patients present with hypertension (FMD is the cause of
10% of cases of renovascular hypertension) and/or renal
failure. Smoking accelerates the onset and increases the
severity.
• Subtypes include intimal, medial (99% of cases of hyper-
tension), and adventitial.
• Treatment is clinical observation for asymptomatic pa-
tients, angioplasty (fi rst-line) for symptomatic patients,
and surgery (aortorenal bypass) for patients with refrac-
tory cases. Unlike atherosclerosis, FMD rarely requires
endovascular stent placement.
■
Other Imaging Findings
• Conventional angiography, computed tomographic angiog-
raphy, and magnetic resonance angiography demonstrate
beading of the renal artery that typically spares the medial
third, is usually unilateral and right-sided, and occasionally
involves branch vessels.
• Associated fi ndings may include true and dissecting
aneurysms, arteriovenous fi stulas, thrombosis, and distal
embolization.
• Other distributions aff ected may include the iliac, carotid,
mesenteric, and brachial arteries.
✔ Pearls & ✘ Pitfalls
✔
Angioplasty results in high rates of technical success
(> 90%), patency, and clinical response.
✔ The primary patency rate at 4 years is 69%.
✔ The cumulative patency rate at 4 years is 85 to 94%.
✔ Clinical response: for patients with hypertension, the
cure rate is 22 to 39%, and the improvement rate is 31 to
59%.
✘ Complications include dissection, rupture, occlusion, and
distal embolization with infarction.
✘ Complication rates for angioplasty of FMD are much
lower than those for angioplasty of atherosclerotic renal
arteries.
✘ Arterial irregularity may persist after angioplasty, but the
clinical response is excellent, and the urge to overdilate
should be resisted.
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167
Case 84
■
Clinical Presentation
The patient is a 57-year old man scheduled for chemoembolization of a hepatocellular carcinoma.
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168
RadCases Interventional Radiology
■
Imaging Findings
Three-dimensional volume-rendered computed tomographic
angiogram (CTA) shows a common arterial trunk supplying the
splenic ( arrowheads ), superior mesenteric ( small arrows ), and
common hepatic ( large arrow ) arteries.
■
Diff erential Diagnosis
• Celicomesenteric trunk: Indicated by a common origin of
the celiac artery and superior mesenteric artery (SMA).
■
Essential Facts
• Celicomesenteric trunk is a mesenteric arterial anomaly in
which a common trunk supplies the origins of the celiac
artery and the SMA. It occurs in < 1% of persons.
• Clinical signifi cance: compared with persons who have
separate origins of the celiac and mesenteric arteries, these
patients are more prone to mesenteric ischemia if stenosis
or obstruction develops in the trunk because of the larger
distribution supplied by a single vessel.
• Mesenteric arterial anomalies deserve careful consider-
ation because they can infl uence the severity of mesen-
teric ischemia and the clinical success and complication
rates of procedures such as transarterial chemoemboliza-
tion (TACE) of liver tumors and abdominal operations such
as liver transplant.
• Other anomalies of the hepatic artery (HA) include the
following:
• Replaced right HA off SMA (< 16%)
• Replaced left HA off left gastric artery (< 10%)
• Replaced left and right HAs (< 1%)
• Accessory left HA (< 8%)
• Accessory right HA (< 7%)
• Replaced common HA from SMA (< 5%)
• Other (< 1%)
■
Other Imaging Findings
• Anomalous mesenteric arteries can be detected with
conventional angiography, CTA, or magnetic resonance
angiography.
✔ Pearls & ✘ Pitfalls
✔
Injection of chemoembolization or radiotherapy agents
into anomalous branches of the HA (nontarget emboliza-
tion) can injure the corresponding organ.
✔ In many cases, nontarget chemoembolization of these
anomalous arteries can be avoided by further subselec-
tion of HA branches to tumor, or by coil embolization of
these anomalous vessels before the injection of chemo-
therapeutic agents.
✘ Chemoembolization of the stomach or duodenum can
cause necrosis, ulceration, or perforation.
✘ Chemoembolization of the cystic artery can cause chemi-
cal cholecystitis.
✘ Chemoembolization of the dorsal pancreatic or pancre-
aticoduodenal artery can cause pancreatitis.
• Other HA branch anomalies include the following:
• Right gastric: normal origin is proper HA, anomalous
origin is gastroduodenal artery (GDA) or left, right, or
common HA.
• Cystic: normal origin is right HA, anomalous origin is
replaced right, accessory right, common, or left HA.
• Pancreaticoduodenal: normal origin is GDA, anomalous
origin is HA branches.
• Dorsal pancreatic: normal origin is splenic artery,
anomalous origin is right HA.
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169
Case 85
■
Clinical Presentation
A 7-year-old boy struck by a car is brought to the emergency department.
Further Work-up
A
B C
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