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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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112
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RadCases.thieme.com RadCases Interventional Radiology
■
Imaging Findings
A B
C D
(A) Arterial-phase, contrast-enhanced CT scan shows contrast lling an outpouching (arrow) adjacent to the common femoral artery (CFA). (B) Color Doppler
image shows a narrow neck (arrowhead) leading from the CFA to a pseudoaneurysm (PSA) (arrow) exhibiting the “yin–yang” sign. (C) Doppler ultrasound image
shows bidirectional arterial ow (arrow) within the PSA (“to-and-fro” waveform). (D) Following thrombin injection, no color ow is noted in the PSA (arrow).
■ Dierential Diagnosis
• Iatrogenic femoral artery pseudoaneurysm (PSA):
The “yin–yang” sign is characteristic of this entity.
• Femoral aneurysm: A true aneurysm will not show the
“to-and-fro” waveform.
■ Essential Facts
• PSAs are aneurysms contained by less than three layers
of the vessel wall—occasionally by only the surrounding
soft tissues and organizing hematoma.
• Femoral PSAs result from arterial catheterization with
an incidence of 0 to 2%—most commonly, when larger
sheaths are required for intervention.
• Other causes include bypass graft anastomosis, trauma,
and infection. Anticoagulation, hypertension, and obesity
are risk factors.
• Larger PSAs (. 2 cm) tend to remain patent and
may continue to grow, increasing the risk of rupture.
Complications may include massive hemorrhage and
compartment syndrome with vascular or neurologic
compromise. Small PSAs more commonly thrombose
spontaneously.
• Imaging considerations:
• Doppler ultrasound is used to screen patients with
pulsatile groin swelling after catheterization to distinguish
hematoma from pseudoaneurysm. Signs of PSA include:
“Yin–yang” color pattern representing swirling ow.
“To-and-fro” waveform at the conduit between the
PSA and the parent artery.
• CT angiography better denes the size of the PSA, the
vessel of origin, and the neck length and diameter in
order to plan treatment.
• Small PSAs may be treated or watched with serial
Doppler ultrasound. Large PSAs are treated.
• Treatment options for femoral PSAs:
• Ultrasound-monitored compression. Advantages
of this option are low risk and low cost, but
disadvantages are long procedure times, patient
discomfort, and a high recurrence rate in
anticoagulated patients.
• Thrombin injection. This option has largely replaced
compression as the therapy of choice for narrowneck PSAs. For large-neck PSAs, the risk of distal
embolization may be too great for thrombin injection.
Increments of 100 IU of thrombin in 0.1 mL of saline
are slowly injected under ultrasound monitoring
until thrombosis is observed, typically requiring a
total of 200 to 750 IU. Complications include distal
embolization and allergic reaction to thrombin.
• Coil embolization. If the parent artery is a peripheral
branch, thrombin injection is still an option, but
some cases may be treated with coil embolization.
Source branches include inferior epigastric, femoral
circumex, deep femoral, and deep circumex iliac
arteries.
• Stent graft. More suitable for PSAs with large necks
originating from large parent arteries.
• Surgical repair. Reserved for PSAs for which minimally
invasive methods fail or are not feasible.
ü Pearls and û Pitfalls
8û Stent graft placement across the hip articulation to
treat common femoral artery PSAs is usually avoided
because repetitive motion can lead to endoleaks, new
PSA formation, stent fracture, and stent occlusion.
Case 57
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A
■ Clinical Presentation
A 58-year-old man with a history of bacterial endocarditis and heart failure presents with fever and abdominal pain.
■ Further Work-up
B
C
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■
Imaging Findings
A
(A, B) Arterial-phase, contrast-enhanced CT scan with axial and coronal reformatting shows a large enhancing aneurysm (arrow) adjacent to branches of
the superior mesenteric artery (SMA). A left ventricular assist device is present. (C) Selected SMA arteriogram shows a narrow-necked aneurysm (arrow)
originating directly from the SMA. (D) Successful embolization was achieved with coils placed within the aneurysm sac (large arrow) and a plug placed in
the neck (small arrow).
■ Dierential Diagnosis
• Mycotic aneurysm: Top choice for a large, thick-walled,
contrast-lled sac in the setting of fever, bacterial
endocarditis, and heart failure requiring a ventricular
assist device. More convincing CT signs of infection
are not present, such as fat stranding, abscess, or gas
associated with the aneurysm.
• Traumatic or iatrogenic pseudoaneurysm: A possibility,
given the absence of other signs of arterial disease.
■ Essential Facts
• Superior mesenteric artery (SMA) aneurysms account for
, 6% of visceral artery aneurysms.
• Septic thromboembolism is the most common cause,
and as a result, mycotic aneurysms tend to occur at
branch points where emboli lodge. Other causes include
adjacent peritoneal or mesenteric infection/inammation
as well as superinfection of traumatic aneurysms and
pseudoaneurysms.
• Staphylococcus aureus and Streptococcus species are the
most common causes; in many cases, multiple organisms
including enteric ora may be cultured. No organism is
identied in 25%.
• Up to 90% of clinically signicant peripheral artery
emboli originate from the heart. Etiologies include
atrial arrhythmias, mitral valve disease, and fungal or
bacterial endocarditis. Other proximal arterial sources of
thromboemboli include upstream aortic aneurysms and
ulcerated atherosclerotic plaque.
• Mycotic aneurysms can enlarge rapidly and are highly
prone to rupture, particularly during the active period
of infection. Rupture is the presenting condition in up
to 50% of cases of SMA aneurysms, with a high rate of
mortality (up to 90%). Other clinical signs include fever,
abdominal pain, and a palpable abdominal mass.
• Imaging considerations:
◦ Multiphase CT scanning helps to plan surgical or
endovascular therapy and identies signs of rupture
such as frank contrast extravasation, perianeurysmal fat
stranding, and hematoma.
B C
◦ Regional infectious or inammatory causes can be
excluded. Signs of infection include perianeurysmal
uid collections, fat stranding, and gas within or
adjacent to the aneurysm.
• Treatment considerations:
◦ Treatment is almost always indicated because of the
high risk of rupture.
◦ Mycotic aneurysms are initially treated with antibiotics
prior to surgical or endovascular intervention.
◦ Surgical resection of the aneurysm is commonly
required for ongoing infection, rapid expansion, and
rupture. Presurgical embolization may be performed
to stabilize patients or buy time to surgical candidacy.
Depending on anatomical and clinical ndings, arterial
ligation and reperfusion via bypass or reimplantation
may be necessary.
◦ Endovascular management options may be considered
after antibiotic treatment in slow-growing, unruptured
mycotic aneurysms.
◦ Some aneurysms may be packed with coils (saccular) or
treated with back door–front door coil placement.
◦ Wide-neck aneurysms may be treated with stent-
assisted coil embolization. A self-expanding stent is
placed within the parent artery across the aneurysm
neck to prevent nontarget coil embolization during
aneurysm packing.
◦ Percutaneous thrombin injection is an option for
narrow-necked, saccular aneurysms of the visceral
arteries.
◦ Covered stents are typically avoided in cases of ongoing
infection.
Pearls and Pitfalls
8 Most SMA aneurysms should be treated rather than
followed with imaging because they commonly rupture,
resulting in a high mortality rate compared to other
visceral aneurysms (50 vs. 10%).
8 Surgery is typically required for ongoing infection
and rapidly expanding or ruptured aneurysms and
pseudoaneurysms.
D
Case 58
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A
■ Clinical Presentation
A 37-year-old man presents with increasingly cold ngers over the last year.
B C
RadCases.thieme.com RadCases Interventional Radiology
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■
Imaging Findings
A B, C
(A) Conventional angiogram at the start of the venous phase of imaging shows persistent opacication of the ulnar artery, which is obstructed at the
level of the hamate bone (large arrow); the hypothenar tissues are supplied by a collateral branch (arrowhead). Beading of the ulnar artery is suspicious
for brous dysplasia (small arrow). (B) Hand angiogram shows abrupt occlusion of multiple digital arteries (arrows) of the second through fourth digits as
well as aneurysms or ectasia (arrowhead) of palmar collaterals. (C) Delayed-phase image shows diminished perfusion to the hypothenar eminence (arrow)
caused by absence of the ulnar components of the supercial and deep palmar arches.
■ Dierential Diagnosis
• Hypothenar hammer syndrome (HHS): Indicated by
occlusion of the ulnar artery at the hamate bone and
bromuscular dysplasia, a common associated nding in
HHS. The ulnar artery serves as a source of distal emboli,
although involvement of the digital arteries of the fourth
and fth digits is more common than involvement of the
second through fourth digits, as in this case.
• Embolus: Embolus from a more proximal source (cardiac
or proximal arterial aneurysm) is a possibility given the
abrupt cuto of multiple digital arteries as well as the
ulnar artery.
• Atherosclerosis: Less likely because this is a young adult
without signicant arterial disease elsewhere.
■ Essential Facts
• Hypothenar hammer syndrome (HHS) is occlusive injury
to the ulnar artery as it passes the hamate bone (Guyon’s
canal); it is usually caused by repetitive occupational
trauma to the hypothenar tissues. High-risk occupations
include roofers, mechanics, carpenters, and jackhammer
operators.
• HHS may be isolated or associated with brous dysplasia
of the ulnar artery as in this case, which is then
exacerbated by repetitive blunt trauma.
• If aneurysmal, the aected ulnar artery may serve as a
source of distal emboli. In this case, small aneurysms
of collateral palmar arteries are noted, which may have
resulted in emboli to the digital arteries.
• Clinical presentation includes ischemia (in cases of
incomplete palmar arches or distal emboli as in this case)
or numbness in the fourth and fth digits (compression
by adjacent ulnar aneurysm or direct eect of repetitive
trauma).
• No endovascular treatment exists. Surgical bypass is
performed for severe cases, but early rethrombosis is
common.
• Imaging considerations:
• Doppler ultrasound can screen for ulnar thrombosis
and aneurysms.
• CT angiography is the best noninvasive tool for
diagnosis, but MR angiography may provide sucient
distal arterial opacication.
• Conventional angiography is the gold standard and
may become necessary in equivocal cases or to plan
surgical repair. Administer a vasodilator such as
papaverine in equivocal cases to determine the extent
of vasospasm versus xed occlusion in the aected
hand. Improvement of ow does not exclude HHS
because vasospasm is a common component.
• The contralateral hand may have similar ndings
or a “corkscrew” conguration of the ulnar artery
suggestive of brous dysplasia.
Pearls and Pitfalls
Raynaud’s phenomenon, or secondary Raynaud’s, is
vasospasm superimposed on another disorder and may
complicate HHS. Diagnostic evaluation may benet
from repeat angiography after administration of a
vasodilator such as nitroglycerin or papaverine.
If a component of Raynaud’s phenomenon is suspected,
thoracic sympathectomy is performed in some patients
to reduce sympathetic tone and open thermoregulatory
arteriovenous shunts to increase skin perfusion.
Other treatments include vasodilators such as calcium
channel blockers and prostaglandins.
Case 59
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A
■ Clinical Presentation
A 63-year-old man presents for treatment of an incidental nding on a recent CT scan.
■ Further Work-up
B C
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■
Imaging Findings
A
(A) Contrast-enhanced CT scan shows an ovoid, partially exophytic, well-circumscribed, enhancing right renal mass (arrow). (B) A microwave ablation
antenna (arrow) has been advanced with the tip in the center of the lesion. (C) Post-ablation image showing gas (arrow) in the ablation zone.
■ Dierential Diagnosis
• Renal cell carcinoma: The presumed diagnosis, although
multiphase imaging would provide better evaluation.
• Benign renal tumor: A possibility because smaller renal
masses are dicult to characterize on imaging studies.
■ Essential Facts
• The incidence of renal cell carcinoma (RCC) is increasing,
likely as a result of the increased use of and improvement
of multiphase cross-sectional imaging. This practice
results in an increase in incidental detection of early RCCs
treatable by thermal ablation.
• Treatment of early RCC (, 4 cm):
◦ Nephrectomy or partial nephrectomy for surgical
candidates remains the rst-line treatment.
◦ Ablation is usually used for patients with high surgical
risk, poor renal function, a solitary kidney, or a
hereditary risk of multiple RCCs (e.g., von Hippel–
Lindau syndrome).
• Technique for RCC ablation:
◦ Ablation is performed using cryoablation, microwave
ablation, or radiofrequency ablation (RFA) under CT
guidance.
◦ The lesion is targeted to achieve treatment margins of
5 to 10 mm beyond the tumor.
◦ Immediate CT scanning after treatment can be
performed without contrast. Cryotherapy results in
a well-marginated, uniformly low-density treatment
zone. RFA and microwave ablation result in perinephric
fat stranding, variable density, and occasional gas
within the treatment zone. Immediate hemorrhage is
hyperdense and can be surveilled using noncontrast CT
scanning.
◦ Surveillance, multiphase cross-sectional imaging is
performed at 1, 3, 6, and 12 months; then every 6
months for 1 year; and every 12 months thereafter,
although protocols vary. CT and MRI are options for
post-treatment surveillance. For the CT option, patients
with poor renal function should be prehydrated and
imaged with limited contrast dose.
◦ Residual tumor or local recurrence is indicated by
increase in lesion size and contrast enhancement.
Normal ndings on follow-up imaging include
a hypointense “halo” around the ablation zone
(RFA . cryotherapy) and benign peri-ablational
enhancement (cryotherapy . RFA).
Pearls and Pitfalls
ü Comparable 5-year survival rates have been reported for
early RCC treated by surgical resection versus thermal
ablation, raising the possibility that ablation may be a
rst-line alternative.
ü Exophytic tumors are associated with lower rates of
residual tumor following ablation.
ü Tumors . 3 cm in diameter have a higher rate of
recurrence after successful treatment.
ü Major complications occur in 3 to 5% of cases and
include bowel injury, hemorrhage, and injury to the
renal collecting system (more common with central
tumors and the use of RFA rather than cryotherapy).
CB
Case 60
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A
■ Clinical Presentation
A 54-year-old man with a history of intermittent rectal bleeding presents with sudden onset of severe lower gastrointestinal
hemorrhage. Endoscopic management failed to treat bleeding from a large, exposed artery, and the patient was rushed to
interventional radiology.
B
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■
Imaging Findings
A B
(A) Selected inferior mesenteric arteriogram (IMA) shows an abnormally enlarged branch (arrowhead) of the superior rectal artery supplying a large focus
of extravasation (arrow) into the distal rectum. (B) Successful coil embolization of this branch (arrow).
■ Dierential Diagnosis
• Dieulafoy lesion causing rectal hemorrhage: The
most likely diagnosis, given the presence of a single,
abnormally large extravasating artery.
• Angiodysplasia: Occurs in elderly people, but an abnormal
tuft of vessels and an early draining vein would provide
more specic evidence.
• Neoplasia or infection: Would have nonspecic imaging
ndings; neither is suggested by the history.
■ Essential Facts
• Dieulafoy lesions are abnormally enlarged arterial branches
in the gastrointestinal (GI) submucosa. They are more
common in men (2:1) and occur throughout the GI tract;
most (75%) occur in the stomach, usually along the lesser
curvature. Extragastric versions most commonly occur in
the duodenum and colon and along surgical anastomoses.
• Presentation is usually bleeding requiring admission
(hematemesis if gastric) after a history of recurrent
bleeding.
• Etiology is unknown. They often occur without local
inammation, suggesting a developmental cause.
Patients usually have other conditions such as chronic
renal insuciency, diabetes, cardiovascular disease, and
hypertension.
• Diagnostic screening for lower GI hemorrhage:
◦ Colonoscopy is rst-line for diagnosis and treatment
but requires time for bowel prep, and many cases are
emergent. This exam is eventually performed in all cases
to diagnose the source of bleeding. Failed or infeasible
colonoscopy indicates the need for either a tagged red
blood cell (RBC) study or multiphase CT scanning.
◦ The tagged RBC study localizes and veries active
bleeding, indicated by abnormal radiotracer accumulation
that increases in intensity and moves through bowel
over time. Sensitivity is better than angiography because
bleeding may be slow or intermittent and scans are
performed continuously over hours.
◦ Multiphase CT scanning provides better localization
than the RBC study, with minimal reduction in
sensitivity. The main downside is reliance on active
bleeding at the moment of scanning.
◦ Angiography is performed with the intent to embolize the
bleeding or to localize the source for surgical resection.
• Treatment of lower GI hemorrhage:
◦ Medical treatment resolves most cases—correction of
coagulopathy, uid resuscitation, and transfusion.
◦ Colonoscopy is rst-line using electrocoagulation, laser
coagulation, sclerotherapy, clipping, or banding.
◦ Transarterial embolization (TAE) using coils or plugs
(for large lesions like this) or Gelfoam (Pzer, New York,
NY) is rst line for acute, active bleeding. Particles and
glue have been described to treat angiodysplasia and
vascular malformations, respectively.
◦ Vasopressin infusion has largely fallen out of favor due
to ischemic complications and prolonged treatment
time. Protocol is 0.2 unit/h, which is increased to
0.4 unit/h if bleeding does not stop and is tapered over
12 to 24 hours if bleeding stops.
◦ Surgery is reserved for cases that are unstable or
refractory to less invasive therapies.
Pearls and Pitfalls
ü Endoscopic ultrasound is highly sensitive for Dieulafoy
lesions. Failed endoscopic clipping of Dieulafoy lesions
is usually treated with emergent embolization.
ü Left colonic and rectosigmoid bleeding may be
supplied by the superior rectal artery (from the inferior
mesenteric), the middle rectal arteries (from the
anterior division of the internal iliacs), and the inferior
rectal arteries (from the internal pudendals). Rich
collateralization makes ischemic complications of TAE
exceedingly rare.
ü Right colonic bleeding is less responsive to TAE than is
left colonic bleeding, likely caused by the right-sided
preponderance of angiodysplasia, which has a high
recurrence rate.
Case 61
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A B
■ Clinical Presentation
A 51-year-old woman presents with crampy abdominal pain and urinary frequency.
C D
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