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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3798_Библиотеки_им_академика_М_И_Перельмана.pdf
21 Combined Role of Diagnostic Imaging Modalities
Lymphoscintigraphy and/or SPECT-CT Lymphoscintigraphy
169
Lymphoscintigraphic investigations are of proven value in the diagnosis and management of diseases of the lymphatic system.
1-4
Lymphoscintigraphy or SPECT-CT Lymphoscintigraphy in Relation to the Clinical Presentation of the “Simple” Lymphedematous Situations
Lymphoscintigraphy and/or SPECT-CT lymphoscintigraphy can be used and interpreted by taking into account the origin of the lymphedema and the clinical stage of
the disease.
In Primary Lower Limb Lymphedemas
In primary lower limb lymphedemas (praecox and, especially, tarda) in the early clinical
stage (latent, intermittent, and/or spontaneously reversible, orthostatic, etc.), the classical planar lymphoscintigraphic acquisitions (instead of SPECT-CT) are adequate to
assess lymphatic functional insufficiency. In such situations, the investigational protocol
will evaluate the function of the lymphatic system of the limbs in standardized conditions, i.e., resting, during exercise, and after 1 h of normal activity.5 In patients with
lymphatic dysfunction, conservative management, such as massage therapy, use of
compression garments, and limb elevation, should be recommended initially.
In other kinds of primary lower limb lymphedemas, such as congenital disorders,
clinically more severe disease (staged II to IV), and, in particular, the descending
forms (extending from the root of the limb toward the foot and suggesting lymph
nodal obstructions or lymphadenodysplasias), SPECT-CT maybe useful in addition
to the planar investigations to precisely evaluate the intra-abdominal lymph node
status, especially among obese patients.
In Secondary Lymphedemas
In secondary lymphedemas, SPECT-CT, in addition to planar investigation, is
beneficial for the following applications:
In lower limb edema, for evaluation of intra-abdominal lymph node status, par-•
ticularly among obese patients.
In upper limb edema, for localization of various lymph nodes of potential impor-•
tance (humeral, axillary, apical, retro, or supraclavicular).
170 P. Bourgeois
Fig. 21.1 Posterior view centered on the pelvis obtained in one woman with congenital right
lower limb primary lymphedema. Peripheral injection showed no lymph nodes on the right side
and only inguinal nodes on the left side. Intradermal injection of the 99mTc-HAS-nanocolloid was
then performed in the external and lateral part of the right buttock (horizontal arrow). With manual
lymphatic drainage, the tracer was shown to flow posteriorly through superficial dermal collateralization toward the right costo-lumbar area (right to left oblique arrow), to reach and cross the
midline (vertical arrow), and from there to reach the left inguinal nodes through normal right-sided
lymphatic vessels (left to right oblique arrow)
Lymphoscintigraphy to Demonstrate the Collateralization Pathways
When no lymph nodes are visualised in the inguinal and/or iliac regions after peripheral subcutaneous injections of the radiolabeled colloid in the feet, and when no
lymph nodes are visualized in the axillary and/or clavicular areas after peripheral
subcutaneous injections of the radiolabeled colloid in the hands, it may be necessary
to perform intradermal injections of the same tracer in the external part of the root
of the edematous limb(s) to demonstrate lymphatic collateralization pathways6
(Figs. 21.1, 21.2). The results of such injections will be of the utmost importance for
physical therapists, so that they can be informed of the possible collaterals requiring
stimulation.
SPECT-CT Lymphoscintigraphy for the Lymphedematous
Disorders Complicated by Chylous Reflux and/or Leakage
SPECT-CT lymphoscintigraphy (after conventional three-phase planar acquisitions)
is particularly useful in patients with chylous reflux or/and leakage, either clinically
obvious
be performed in the following situations:
7-10
or suspected. According to our experience, abdominal SPECT-CT should
21 Combined Role of Diagnostic Imaging Modalities
171
Fig. 21.2 From left to right and from top to bottom, anterior views centered on the axilla in a woman
with post-therapeutic left upper limb lymphedema where the subcutaneous injection of 99mTc-HAS
nanocolloid in the first interdigital space of the hands showed normal right axillary nodes, but no
node in the left axilla. Intradermal injection was then performed at the level of the upper and external
part of the left arm (vertical arrow) and the tracer was shown to spontaneously flow toward the retroclavicular lymph nodes (left to right oblique arrows) and also toward the left anterior chest wall, to
cross the midline to reach the opposite axillary lymph nodes (right to left oblique arrows)
In any patient in whom activity is observed in the abdomen that does not corre-•
spond with classical anatomical localization of infra-diaphragmatic lymph nodes
(Figs. 21.3, 21.4).
When lymphatic reflux and dermal backflow are observed in the genital organs •
and/or at the level of the abdominal wall (Figs. 21.5, 21.6).
Lymphoscintigraphy, Lymphoceles, and Lymphangiomas?
Identification of lymphangioma by lymphoscintigraphy is rarely reported.
these patients, as in some patients with lymphoceles, SPECT-CT lymphoscintigraphy will be of clinical utility in order to demonstrate the exact anatomical connections and relationships between the lymphatic collection and the lymphatic vessels
or nodes.
11-14
In
172 P. Bourgeois
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Fig. 21.3 Anterior whole-body scanning (WBS) obtained (after one subcutaneous injection of
99mTc-labeled HAS nanosized colloid in the first interdigital space of each foot, the patient lying
on the examination table), from right to left, after 30 min without movement, after 5 min of tiptoeing, and after 1 h of walking. This man was sent for evaluation of right lower limb lymphedema
(he also had pre-pubic edema on clinical examination) secondary to surgery and radiotherapy for
prostatic carcinoma. After 30 min without movement, the tracer has reached the first inferior inguinal node on the right side (arrow 1), but progressed only to the level of the knee on the left side.
After 5 min of tiptoeing, lymphatic reflux is seen in collaterals toward the external part of the right
buttock (arrow 2), up to and in the mid internal part of the thigh (arrow 3), and in the right prepubic area (arrow 4). One right common iliac lymph node is observed (arrow 5) as well as – faintly
– two left retro-clavicular lymph nodes (arrow 6), proving that the thoracic duct is pervious. After
1 h of walking, the reflux of lymph in the superficial collateralization lymphatics extends to the
upper and inner half of the right thigh (arrow 7), but one abnormal zone of activity is also demon-
strated in the mid supra-pubic part of the abdomen (arrow 8)
21 Combined Role of Diagnostic Imaging Modalities
173
Fig. 21.4 From left to right, selected transverse, sagittal, and coronal/frontal fused slides from the
SPECT-CT across the abdomen and pelvis showing nicely (1) (top to bottom oblique arrows) that
the abnormal zone of activity seen on the planar WBS image in the mid supra-pubic part of the
abdomen corresponds, in fact, to lymph flowing back from lumbar aortic nodes in the digestive
tract and (2) (bottom to top oblique arrow) dermal back flow in the right pre-pubic area
X-Ray Computed Tomography?
Computed tomography is rarely necessary for the diagnosis of simple lymphedematous disorders, but may be useful for the pre-treatment evaluation and initial workup, because it provides an objective depiction of anatomical abnormalities.
15
Computed tomography will be of greater clinical utility, and is particularly useful, in patients with lymphangiectasia, lymphangioma, or lymphangiomatosis. In
these patients, CT can be used to assess both the nature and distribution of lesions16
or to facilitate their catheter-guided percutaneous sclerosis or obliteration.
17
Positron Emission Tomography or Positron Emission Tomography Combined with X-Ray Computed Tomography?
As mentioned in the Introduction, the use of PET alone is becoming progressively
less prevalent in the Nuclear Medicine department, being replaced by hybrid devices
combining PET and CT.
174 P. Bourgeois
1
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5
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6
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7
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Fig. 21.5 Anterior WBS obtained (after one subcutaneous injection of 99mTc-labeled HAS nanosized colloid in the first interdigital space of each foot, the patient lying on the examination table),
from right to left, after 30 min without movement, after 5 min of tiptoeing, and after 1 h of walking.
This young woman did not complain of lower limb edema, but was referred for evaluation of intermittent lymph leakage at the level of her right labium majorum. After 30 min without movement,
the tracer reached the first inferior inguinal node on the left side and all the inguinal nodes on the
right side, but with lymphatic collaterals appearing from the inguinal nodes toward the external
part of the buttock (arrow 1). After 5 min of tiptoeing, infra-diaphragmatic lymph nodes are now
seen on both sides (and right collaterals are confirmed); the beginning of lymphatic reflux in the
right labium majorum can also be observed (arrow 2). After 1 h of walking, the reflux of lymph in
the right magna labia is now obvious (see arrow 3), but abnormal zones of activity are also demonstrated in the right and left lateral part of the abdomen (arrows 4 and 5) as well as at least two
right para-renal lymph nodes (arrow 6) and, at the supradiaphragmatic level, there is a completely
abnormal presentation of the great lymphatic thoracic duct with right and left components persisting (arrows 7 and 8). For more information on these anomalies, see Bourgeois et al.
33
21 Combined Role of Diagnostic Imaging Modalities
Fig. 21.6 Coronal/frontal slide from the SPECT across
the chest, the lumbar aortic nodes and the ilioinguinal
nodes showing nicely, in the mediastinum, serpentine
channels forming the thoracic duct and, in the abdomen,
the lake of lymphatic activity in the right and left
digestive tract
175
In the management of secondary upper and/or lower lymphedemas, PET-CT
imaging using an appropriate tracer (18F-DG, 11C-Choline, etc.) is useful, for
instance, when serum tumor markers are increasing or when lymphedemas become
treatment-resistant. Focusing on the use of CA 15-3 in breast carcinoma and CA
125 in ovarian carcinoma, Pecking et al.18 found the sensitivity and predictive value
of PET-CT with 18F-FG to be nearly 100%. An additional application of PET-CT
in such patients is to exclude and/or demonstrate distant (non-nodal) metastases.
As shown by Figs. 21.7, 21.8, this can also be useful in some patients in a first
time classified as with primary lymphedemas.
Magnetic Resonance Imaging and/or Lymphangio-MRI with Injection of Contrast Enhancement?
Magnetic Resonance Imaging in the Diagnosis of Pathologically Positive Lymph Nodes?
With regard to the possible use of MRI to evaluate malignant involvement of
lymph nodes (sometimes responsible for the development, aggravation, and/or
resistance of lymphedema to treatment), Klerckx et al. performed a systematic
176 P. Bourgeois
Fig. 21.7 Anterior whole-body scanning (WBS) obtained (after one subcutaneous injection of
99mTc-labeled HAS nanosized colloid in the first interdigital space of each foot, the patient
lying on the table of examination), from right to left, after 30 min without movement, after 5 min
of tiptoeing, and after 1 h of walking. This woman was sent for evaluation of left lower limb
lymphedema. After 30 min without movement, the tracer has reached the first inferior inguinal
node on both sides, but the beginning of lymphatic reflux is seen at the level of the distal part of
the left calf (arrow 1). After 5 min of tiptoeing, lymphatic reflux in the left calf is more obvious
(arrow 2). After 1 h of walking, the reflux of lymph in the superficial collateralization lymphat-
ics is obviously extended to the left ankle (arrow 3), one left popliteal lymph node (arrow 4),
and one left retro-clavicular lymph node (arrow 6), but not the left common iliac nodes (arrow
5). On the basis of this lymphoscintigraphic examination, the diagnosis of primary lymphedema
tarda was proposed
21 Combined Role of Diagnostic Imaging Modalities
177
Fig. 21.8 The patient later developed left sciatica and blockage of the common iliac vein was
suspected. PET-CT after IV injection of 18F-DG was performed and demonstrated (on the selected
transverse PET-CT slides) a hypermetabolic process later histologically proven to represent metastatic tumor of uterine cervix origin
review and meta-analysis of existing data on the accuracy of gadoliniumenhanced MRI for staging lymph node metastases.19 The weighted estimates of
sensitivity and specificity for all studies combined were 0.72 (95% confidence
interval [CI] = 0.66–0.79) and 0.87 (95% CI = 0.82–0.91) respectively. Estimates
of sensitivity and specificity were essentially unchanged for studies that used a
single malignancy criterion (n = 11 studies) or multiple malignancy criteria with-
out contrast enhancement (n = 6 studies). The sensitivity increased to 0.84 (95%
CI = 0.70–0.92), with a specificity of 0.82 (95% CI = 0.72–0.89), for the nine
studies that incorporated contrast enhancement in their multiple malignancy
criteria.
178 P. Bourgeois
Heavily T2-Weighted Imaging or Magnetic Resonance Lymphangiography for Lymphedemas?
According to Lu et al.,20 heavily T2-weighted imaging has greater sensitivity and
the MRL image has higher legibility for the detection of the pathologically modified
lymphatic vessels and accompanying complications.
MRI or MRL in Lymphedemas?
In a series of 39 patients (27 male and 12 female) with lower extremity lymphedema
and/or skin lymphorrhea of the abdominal wall or external genitalia with peripheral
and central lymphatic malformations, Liu et al.21 reported that non-contrast 3D MRI
provided extensive information on the anatomy of the dysfunctional vasculature
as well as on the effects of lymphatic dysfunction on local structures and tissue
composition.
With the intracutaneous injection of gadobenate dimeglumine into the interdigital webs of the dorsal foot of 27 patients with primary lymphedema, the same
authors22 reported, more recently, that contrast MR lymphangiography was capable
of visualizing the precise anatomy of lymphatic vessels and lymph nodes in lymphedematous limbs and also provided information concerning the functional status
of lymph flow in the lymphatic vessels and lymph nodes.
Notohamiprodjo et al. reported on the use of intracutaneous injection of gadolinium-diethylene-triamine-pentaacetic-acid in 16 patients,23 concluding that MRL at
3.0 T provides very high spatial resolution and anatomical detail of normal and
abnormal peripheral lymph vessels. However, they also stated that the examination
was non-diagnostic in one case where contrast medium was injected subcutaneously instead of intracutaneously and that venous contamination (always present)
was diagnostically problematic in another patient.
In a small series of patients, Lohrmann et al.
24,25
also demonstrated the efficacy of MRI in lipo-lymphedemas and in post-traumatic edemas of the lower
extremities.
MRI in Chylous Reflux?
Magnetic resonance imaging permits visualization of deep-lying, ordinarily inaccessible lymphatic vessels, such as those of the retroperitoneum in chylous reflux
syndromes.26 Combined transaxial and coronal imaging allows visualization of
these lymphatic vessels and provides visual guidance for the injection of sclerosing
agents for the obliteration of external lymph leakage (e.g., skin, vagina) or bulky
lymphangiomas.
26
Non-enhanced MRI is also a feasible option for locating and
depicting the morphological features of the thoracic duct27 and, thus, might be of
interest in chylothorax situations.