short notes about cervical lymph nodes , leveling, features in normal, reactive and metastatic condition , using US, CT, MRI & PET scan

1. IMAGING OF
CERVICAL
LYMPH NODES
Mohamed Wasel
M.Sc, EDIR , EDiNR
Alharda Armed Forces Hospital
2019

2. Outlines
–Cervical lymph nodes classification
developed by Som. et al, which groups
lymph nodes in levels .
–Ultrasonic features of cervical lymph node .
–CT features of cervical lymph nodes.
–MRI feasures of cervical lymph nodes .
– PET scan feasures of cervical lymph nodes .

3. To use the imaging-based nodal classification developed by Som its essential to know
the anatomic landmarks of the classification:
1. The skull base at the jugular fossa,
2. The bottom of the body of the hyoid bone
3. The bottom of the cricoid arch .
4. The top of the manubrium .
5. The back edge of the submandibular gland .
6. the back edge of the sternocleidomastoid muscle .
7. The lateral posterior edge of the anterior scalene muscle,
8. The anterior edge of the trapezius muscle,
9. Both the internal carotid and common carotid arteries, the internal jugular vein,
10. The clavicle, the medial margin of the anterior belly of the digastric muscle, and
11. The mylohyoid muscle.

4. Fig. 1
References: Imagiologia Geral, Centro Hospitalar Lisboa Norte, Hospital de Santa
Maria - Vila Nova De Gaia/PT

5. Fig. 2
References: Imagiologia Geral, Centro Hospitalar Lisboa Norte,
Hospital de Santa Maria - Vila Nova De Gaia/PT

7. - Level I includes all nodes above the hyoid bone, below the
mylohyoid muscle, and anterior to the posterior edge of the sub-
mandibular gland..

8. - Level IA represents the nodes that lie between the medial margins of the
anterior bellies of the digastric muscles.
- Level IB represents the nodes that lie posterior and lateral to the medial
edge of the anterior belly of the digastric muscle.

9. Level II is
limited cranially by the skull base and extends caudally to the the lower body
of the hyoid bone. Level II nodes lie
anterior to the posterior edge of the sternocleidomastoid muscle and lie
posterior to the posterior edge of the submandibular gland.

10. •Level II nodes can be subclassified into levels IIA and IIB.
•Level IIA nodes are level II nodes that lie posterior to the internal
jugular vein and are inseparable from the vein or that lie anterior, lateral,
or medial to the vein.
•Level IIB nodes lie posterior to the internal jugular vein and have a fat
plane separating the nodes and the vein .

11. Level III nodes lie
between the of the lower body of the hyoid bone and the level of the lower
margin of the cricoid cartilage arch,
anterior to the posterior edge of the sternocleidomastoid muscle and
lateral to the medial margin of either the common carotid artery or the
internal carotid artery.

12. Level III nodes lie
between the of the lower body of the hyoid bone and the level of the lower
margin of the cricoid cartilage arch,
anterior to the posterior edge of the sternocleidomastoid muscle and
lateral to the medial margin of either the common carotid artery or the internal
carotid artery.

13. Level IV nodes lie
between the level of the lower margin of the cricoid cartilage
arch the level of the clavicle,
anterior and medial to an oblique line drawn through the
posterior edge of the sternocleidomastoid muscle and the
posterolateral edge of the anterior scalene muscle

14. . The medial aspect of the common carotid artery is the landmark that separates level IV nodes (lateral
to this artery) from level VI nodes (medial to this artery).

15. Level V nodes extend from the skull base, at the posterior border
of the attachment of the stermocleidomastoid muscle, to the level
of the clavicle

16. . Level V nodes all lie
anterior to the anterior edge of the trapezius muscle.
Between the levels of the skull base and the bottom of the cricoid arch, these
nodes are situated posterior to the posterior edge of the sternocleidomastoid
muscle. Between the axial level of the bottom of the cricoid arch and the level of
the clavicle,

17. level V nodes lie posterior and lateral to an oblique line through the posterior
edge of the sternocleidomastoid muscle and the posterolateral edge of the
anterior scalene muscle.
The level V nodes can be subdivided into VA and VB nodes. The lower margin
of the cricoid is the landmark that separates level VA (superior to the cartilage)
and level VB (inferior to the cartilage)

18. Level VI nodes lie
inferior to the lower body of the hyoid bone,
superior to the top of the manubrium, and

19. Level VI nodes lie
between the medial margins of the left and right common carotid
arteries or the internal carotid arteries.

20. Level VII nodes lie
caudal to the top of the manubrium in the superior mediastinum,
between the medial margins of the left and right common carotid arteries.

21. These superior mediastinal nodes extend caudally to the level of
the innominate vein.

22.  Size:
 The size of LN cannot
be used as the sole
criterion in DD.
 An increase in LN
size on serial
examinations.
 Changes in the size
of malignant nodes.

23.  Nodal Borders& margins:
 Metastatic nodes have sharp borders.
Due to tumor infiltration and reduced fatty deposition
within LN leads to Increased acoustic impedance
difference between LN and the surrounding tissues.

24.  Reactive nodes
usually show un-
sharp borders.
 Un-sharp borders
due to edema &
inflammation of
surrounding soft
tissue.

25. Shape Feature:
 Malignant and
TB nodes round.
 Reactive and normal
nodes usually oval.
 The L/S ratio was
used to characterize
this feature.

26.  Echogeneity:
 Homogeneous hypo-
echoic pattern with
preserved echo-
genic hilum mainly
observed in benign
nodes.
 Heterogeneous and
anechoic patterns
with loss echogenic
hilum are observed in
metastatic nodes.

27.  Normal and reactive
nodes predo-
minantly hypo-
echoic.
 Metastatic nodes
may be hypo or
mixed hypo and
eccenteric hyper-
echoic component.

28.  Vascular Pattern:
Normal and reactive
lymph nodes tend to
have central hilar
vascular pattern.
 club- or Y-shaped and
extended from the
extra-nodal area into
deep portion of the node.
 May be appear as
apparently a-vascular
lesion.

29.  Metastatic and
lympho-matous
nodes usually show
peripheral or mixed
vascularity.
 The presence of
peripheral vascularity
strongly suggesting
of a pathologic
process.

30. •Intranodal calcification is rarely found in cervical
lymphadenopathy. However, about 50-69% of metastatic
nodes from papillary carcinoma of the thyroid show
calcification which is punctuate, peripherally located and
may show acoustic shadowing .
•Intranodal calcification may be found in lymphomatous
and tuberculous nodes after treatment but the
calcification is usually dense and shows acoustic
shadowing.
Calcification

32.  Nodal parenchyma
exhibited homogeneous
and low echogenicity.
 Regular margin and oval
or flattened in shape.
 The hilum was identified
as a highly echogenic
structure in the central
part of the node.
 On power Doppler,
usually hypovascular or
has hilar vascular
pattern.

33.  Ill defined margin of
enlarged LN.
 Central decreased
echogenicity.
 Loss hilum.
 On power Doppler,
increase peripheral
vascularity.

34.  Nodal parenchyma
exhibited inhomogeneous
low or mixed echogenicity.
 Irregular margin with
round shape.
 Sharp borders.
 Loss of normal hilar
echogenicity.
 On power Doppler
sonograms, has peripheral
or mixed vascular pattern.

36.  CT SCAN:
 scanning orientation was parallel to the Frankfurt
horizontal line.
 Start point at skull base down to the level of
aortic arch.
 3 mm in thickness.
 A collimation of 3 mm, a pitch of 1:1, a matrix of
512x512, a display field of view of 23 cm, 120
kVp, and 200 mA.

37.  Was carried out after an IV bolus injection of
contrast material 100 mL (2 mL/kg of body
weight), at a rate of 1.0 mL/sec.
 Started scanning 80 sec after the start of contrast
medium injection.
 Completed in 50–60 sec after the start of
scanning.
 The scanning period (80–140 sec after the start
of contrast medium injection) was confirmed to
be the time when the lymph node showed
appropriate contrast enhancement against neck
muscles.

38.  A. short- and long-axis diameters of the node:
 Short-axis diameter: was used as a size criterion.
 Average short-axis lengths of nodes at level I: 7
(reactive) and 11 mm (metastatic).
 Level II: 7 (reactive) and 13 mm (metastatic).
 Level III, IV , V ,VI and VII : 6 (reactive)
and 10 mm (metastatic).
 A long axis diameter of more than 10 mm plus a
long-to-short-axis ratio of less than 1.6,
suggesting metastatic node.

40.  B. Assessment of changes in the internal
architecture:
 The presence or absence of necrosis, We
considered an area of low attenuation (10–18
HU) to be evidence of nodal necrosis.
 The margin, categorized as well or ill defined.
 Enhancement pattern, described as
homogeneous or heterogeneous .

42.  Discrete, smooth and
well-defined kidney or
cigar shaped soft-tissue
structures .
 The hilum composed of
fat tissue attenuation.
 No necrosis.
 Homogenous and
uniform, enhancing
criteria and attenuation.

43.  Rounded shape with
ill defined margin.
 The long-to-short
axis ratio decreases.
 Eccentric cortical
hypertrophy.
 Central necrotic
content.
 Heterogeneous
enhancing pattern.

44.  Ill defined peripheral
enhancing thick wall.
 Intra-nodal
septation.
 Central hypo-dense
non enhancing fluid
collection.
 Marked stranding of
adjacent fat
?cellulitis.

45.  Conventional MRI criteria used in clinical imaging
studies are morphologic criteria including:
A. Maximum short axial diameter.
B. Presence of necrosis and loss of LN hilum.
C.Heterogeneous enhancement and peri-nodal
infiltration.
 A size criterion and presence of necrosis are relatively
objective.
 But the other criteria are less objective and dependent
on the interpretation of the radiologist.

46.  2D-Single-Shot Diffusion-Weighted Echo Planer
Imaging (ss DWEPI ) has been applied to head and
neck imaging.
 DWEPI provides a quantitative measurement of the
ADC of water protons in tissue.
 ADC value can be used to differentiate malignant
LNs from benign LNs.
 Can be a marker for prediction and early detection
of chemo-radiation therapy response.
 DWEPI also can be used for the early detection of
recurrence.

47.  Axial DW images of cervical lymph nodes were obtained
by using a neurovascular array coil.
 The sequence was repeated for two different values of
gradients (b = 500 and 1000 s/mm2).
 The section thickness was 5 mm.
 Was performed with a matrix of 128 /128, field of view
of 24 cm, and an intersection gap of 1 mm.
 Toincrease the signal-to-noise ratio, the sequence was
repeated four times for each imaging.

48.  Hilum Structure of the
Nodes:
 The hilar fat, has high-
intensity area on T1WIs
and a low-intensity area
on fat suppressedT2WIs.
 The vessels may be
evident in the hilum on
T1WIs and fat suppressed
T2WIs.

49.  Was lost at a
metastatic nodes.
 Narrowed or also lost
in nodal lymphomas.
 Preserved hilum was
noted on benign LN.

50.  Margins of the
Nodes: T1-weighted and fat
suppression imaging was
good for the depiction of
nodal margins.
 Nodal margins blending
into surrounding tissue were
found in metastatic nodes.
 Irregular margins were
found in lymphomas.
 Regular borders were
found on benign nodes.

51.  Parenchymal architecture:
•  Metastatic nodes frequently exhibited heterogeneous architecture
of the parenchyma on T1- or fat-suppressed T2-weighted.
•  Metastatic nodes contained hypo to intermediately intense areas
indicative of cancer cell nests and interstitial fibrous tissue.
•  With or without central hyper-intense areas indicative of
liquefaction necrosis on fat-suppressed T2.

53.  Basically lymphomasexhibited
homogeneous
architecture.
 Heterogeneous architecture of
the nodal ymphomas was
significantly low comparedwith
metastatic nodes.
 heterogeneity in the nodal
architecture may be due tothe
presence of necrotic areas.
 Associated with narrowed
hilum and blood vessels inside,
which were depicted as so-
called small-vessel sign.

55.  The ADC of metastatic
nodes equal to or greater
than 0.73 × 10–3
mm2/sec.

56.  On lymphoma, it had
an ADC equal to or
less than 0.51 × 10–3
mm2/sec.
 Due to increased
nuclear-to- cytoplasmic
ratio and hyper-
cellularity.

57.  PET using the radio-labeled glucose analog 18F-FDG has great
importance in lymph node imaging.
 PET supplies a semi-quantitative metabolic characterization of
tissues that may help to predict tumor behavior.
 The sensitivity and specificity of 18F-FDG PET for identification
of lymph node metastases on a neck level-by-level basis were
higher than those of CT/MRI.
 The incorporation of functional information derived from PET
has the potential factor to improve prognostic stratification and
treatment planning for patients.

58.  Patients were instructed to fast for 6 h before the PET study.
 18F-FDG was administered intravenously.
 For PET/CT scans, oral contrast was administered to patients
during the uptake time.
 No IV contrast material was administered for CT scans.
 Head to mid thigh scans were obtained for all patients.
 PET and CT images were acquired 50 min after the injection of
18F-FDG.
 PET, CT,and fused PET/CT images were available for review
and were displayed in axial, coronal, and sagittal planes.
 PET data were displayed as non-corrected and attenuation-
corrected images as well as in a rotating MIP.

61.  Area of increased 18F-FDG
uptake with intensity higher
than that of surrounding
tissues and did not correspond
to the physiologic bio-
distribution of the radiotracer,
were defined as positive.
 18F-FDG activity only in areas of the physiologic tracer bio-
distribution or no sites of increased uptake were considered
negative.
 The highest activity within a region of interest was measured.
 The standardized uptake value (SUV) was determined as the
highest activity concentration per injected dose per body weight
(kg).

62. •  Area of increased 18F-FDG uptake with
intensity higher than that of surrounding
tissues and did not correspond to the
physiologic bio-distribution of the radiotracer,
were defined as positive.

63. •  18F-FDG activity only in areas of the
physiologic tracer bio- distribution or no sites
of increased uptake were considered negative.
•  The highest activity within a region of interest
was measured.
•  The standardized uptake value (SUV) was
determined as the highest activity concentration
per injected dose per body weight (kg).

64.  18F-FDG uptake was graded visually on the following 5-point
scale:
 0-definitely benign, no uptake.
 1-probably benign, 2.3 (range, 1.4–4.0).
 2-equivocal, 2.6 (range, 1.4–4.4).
 3-probablymalignant, 3.5 (range, 2.1–7.9).
 4-definitely malignant, 6.6 (range, 2.6–24.5).
 SUV of 3.1 was used as the cutoff for positive PET results.