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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5767_Библиотеки_им_академика_М_И_Перельмана.pdf
150
Y. N. Patrunov et al.
c
d
Fig. 8.12 (continued)
[48]. Besides, the changes were more prominent
in the group of patients with severe chronic renal
failure than in the group with moderate renal
failure.
The data of publications on the quantitative
analysis of CEUS for the differential diagnosis of
benign and malignant renal tumors are contradictory. Probably, it is a consequence of the lack of
protocol standardization, the difference in equipment, or the small study sample. The washin rate
in malignant tumors exceeded the same parameter
of benign lesions and also correlated with the
e
degree of differentiation [33]. Peak intensity and
time-to-80% on wash-out were also reported to
provide signicant differences between clear
cell, papillary, and chromophobe renal cell carcinoma subtypes [49]. In small-sized renal cell carcinomas and AMLs, higher values of enhancement
intensity, washout in the late phase, and perilesional rim-like enhancement were reported [50].
However, currently, the quantitative analysis of
renal CEUS remains the subject of scientic study.
It is rarely used in clinical practice except for the
assessment of the tumor response to therapy.
8 Kidneys andAdrenals
a
151
b
Fig. 8.13 Large renal cell carcinoma, which substitutes
2/3 of the kidney with penetration to retroperitoneal fat.
(a) CEUS image. The lesion demonstrates poor enhancement with large avascular areas. Some normal paren-
chyma remains in the upper segment of the kidney. (b)
TIC shows no enhancement of the lesion (yellow ROI)
and typical enhancement of the remaining renal parenchyma (pink ROI). (c) Venous phase CE-CT
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Y. N. Patrunov et al.
c
Fig. 8.13 (continued)
8.5 Adrenals
The adrenal glands are situated near the medial
aspect of the upper poles of each kidney. They are
richly supplied with blood via the superior, middle, and inferior suprarenal arteries, which arise
from the inferior phrenic artery, abdominal aorta,
and renal artery respectively. These vessels form
a plexus within the capsule of the adrenal gland
and form small arteries that descend through the
cortex and medulla. These arteries compose a
capillary network around the medullary secretory
cells. The medullary veins merge to a single adrenal vein, which drains to the inferior vena cava on
the right side and the left renal vein on the left.
Adrenals are normally examined together
with the kidneys due to the anatomical intimacy.
Therefore, most adrenal lesions are detected by
chance and called incidentalomas. Imaging methods detect them in 2–4% of the general population and up to 9–10% in elderly people. The main
two tasks with such a lesion are the evaluation of
its hormonal activity and the risk of malignancy.
Adrenal adenoma is a dominating lesion,
which accounts for about 80% of all incidentalomas. Pheochromocytoma, carcinoma, myelolipoma, cyst, metastasis, etc. exhibit signicantly
lower incidence.
CT condently differentiates adrenal adenoma. A typical adenoma with a native CT scan
has a density from −5 HU to +15 HU.In such
cases, which make more than half of all adrenal
scans, the introduction of the contrast medium is
not required. In other cases, contrast-enhanced
CT is necessary with the calculation of relative
and absolute washout. Adenomas with high specicity demonstrate the values of >40% and
>60%, respectively. All lesions that have lower
washout values with CE-CT are considered not
adenomas, and the specicity of CE-CT in this
group is low. MR has similar diagnostic accuracy
to CT allowing characterizing adenomas regardless of their CT enhancement.
With sonography, a similar approach is impossible. First of all, the features of the visualization
of adrenal glands limit both grayscale and
contrast- enhanced ultrasound. Adrenals are
located deeply in the retroperitoneal space.
Normal adrenals are at and comparable on echogenicity with the surrounding fat. Therefore, conventional US is capable to detect only considerably
large adrenal lesions. The left adrenal gland is surrounded by gas-containing organs, and the US
often fails to determine its masses. The right adrenal lesions are well visualized with the grayscale
US through the liver, but during CEUS, the liver
enhancement negatively affects the imaging quality of the right adrenal lesions. Secondly, the
microbubbles after bolus injection persist in the
blood pool for less than 10min due to their selfdestruction, which has a non-linear character.
This fact does not permit the interpolation of the
CE-CT washout calculation method to CEUS.
EFSUMB guidelines and recommendations
for the clinical practice of CEUS in non-hepatic
applications (update 2017) devoted only two
paragraphs to adrenal diseases [1]. No CEUS criteria were reported to reliably differentiate
between benign and malignant adrenal gland
tumors.
However, simple benign cysts, regardless of
the origin, appear nonenhanced in all vascular
phases (Fig.8.17, Video 8.15). CEUS identies
adrenal cyst, abscess, and hematoma as avascular
lesions [51].
Most adrenal adenomas are hypoenhancing in
comparison with the liver without any typical
vascular pattern [52] (Fig.8.18, Video 8.16).
8 Kidneys andAdrenals
a
b
153
Fig. 8.14 Renal cell carcinoma. (a) CEUS image. The
intrarenal lesion of about 5cm in size with a single nonenhancing uid collection and the otherwise uniform
enhancement. (b) CEUS image. The lesion of 3cm in size
with a small nonenhancing area. (c) TIC shape of the
lesion enhancement (pink ROI) is similar to the same of
the normal renal parenchyma (yellow ROI)
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Y. N. Patrunov et al.
c
Fig. 8.14 (continued)
Other adrenal lesions, such as pheochromocytoma, cancer, and metastasis can demonstrate
various enhancement patterns and do not have
specic signs. CEUS may demonstrate characteristic hypervascularity of some adrenal gland
tumors, e.g., pheochromocytoma, which typically also have necrotic regions with no contrast
enhancement [1, 52, 53] (Fig.8.19, Video 8.17).
In the adrenal gland, the size of the lesion is
important. While the majority of benign masses
are smaller than 3cm, the malignant neoplasms
and pheochromocytoma by the time of their
detection are larger than 3cm. Additionally, the
larger the lesion, the more heterogeneously it
enhances (Fig.8.20, Video 8.18).
The same principle applies to the metastases
in adrenal glands (Fig. 8.21, Video 8.19).
Increased and irregular enhancement practically
excludes adenoma and is an unfavorable prognostic sign. A single metastasis in the adrenal
gland is a rare entity, it is usually accompanied
by metastases in the other adrenal gland or other
organs. The correlation of US ndings with the
patient’s history, clinical, and laboratory data
also facilitates the correct conclusion.
The adrenal tumors, which exhibit specic
symptoms and were suspected based on clinical
and laboratory data, require only precise localization. Since CEUS is not a method for the
detection of the adrenal mass and can only
characterize the already identied lesion, its
utilization for the targeted examination of
patients with adrenal gland hormone disorders
is pointless.
Currently, CEUS of adrenal masses does not
reach the diagnostic value of CE-CT and
MRI. Moreover, in many cases, it does not
provide additional clinically signicant information to standard sonography with Doppler.
However, individual cases may benet from
adrenal CEUS.For example, CEUS could easily
conrm the absence of contrast enhancement in
adrenal hematoma in children and follow them
up without risks associated with iodine contrast
agents and ionizing radiation of repeated CE-CT
examinations [54].
8 Kidneys andAdrenals
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a
b
c
Fig. 8.15 Renal angiomyolipoma. (a) Grayscale US
image reveals a hyperechoic lesion with smooth clear
margins. (b) Color Doppler demonstrates the hypovascularity of the lesion. (c) Early cortical phase CEUS image
demonstrates the beginning of the enhancement of the
lesion at the periphery. (d) The late cortical phase CEUS
image demonstrates the gradual uniform enhancement of
the lesion from the periphery to the central aspects. (e)
Parenchymal phase CEUS shows further enhancement of
the lesion. (f) TIC of the lesion enhancement (pink ROI) is
attened as compared to the same of the normal renal
parenchyma (yellow ROI)
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Y. N. Patrunov et al.
d
e
Fig. 8.15 (continued)
8 Kidneys andAdrenals
f
157
Fig. 8.15 (continued)
158
ab
Y. N. Patrunov et al.
c
Fig. 8.16 Small renal angiomyolipoma. (a) Grayscale
US image reveals typical signs of a renal AML. (b) Color
Doppler demonstrates the hypovascularity of the lesion.
(c) Cortical phase CEUS image demonstrates poor peripheral enhancement of the lesion. (d) Parenchymal phase
CEUS shows persisting hypoenhancement. (e) TIC of the
lesion enhancement (pink ROI) is low as compared to the
same of the normal renal parenchyma (yellow ROI).
(f)Native CT demonstrates typical AML with the density
of -116HU
8 Kidneys andAdrenals
d
159
e
Fig. 8.16 (continued)