This document discusses diagnostic imaging techniques for evaluating lymph nodes in patients with head and neck cancer. It describes the use of ultrasound, CT, MRI, diffusion-weighted MRI, and PET imaging to analyze lymph node characteristics like size, shape, margins, echogenicity, necrosis and vascularity which can help differentiate between metastatic, inflammatory and normal lymph nodes. Quantitative measurements like ADC from diffusion MRI and SUV from PET can also provide diagnostic information and predict cancer spread and treatment response.

1. Head and Neck Imaging.
Ehab Abo-Ulfotouh Helal.
Lecture Of Radio-Diagnosis.

2.  An oval-shaped
organ of the immune
system.
 Distributed widely
throughout the body.
 Linked by lymphatic
vessels.
 Lymph nodes act as
filters for foreign
particles.
 Become enlarged in
various conditions.

8.  Head and neck carcinomas are the sixth most
common malignancy reported worldwide.
 LN metastasis is one of the most important prognostic
factors in patients with head and neck carcinoma.
 The major goals of diagnostic imaging in these patients
is accurate prediction of LN metastasis.
 Not only for the planning of appropriate treatment but
also for monitoring the treatment response.

10.  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.

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

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

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

14.  Medulla Ratio &
distribution:
 If the difference
between 2 parts
was less than 30%.
 This node was
considered absence
of medulla.

15.  The distances from
each edge to the
centroid of the
medulla were
measured.

16.  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.

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

18.  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.

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

20.  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.

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

22.  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.

24.  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.

25.  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.

26.  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, VI and V: 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.

28.  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 .

30.  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.

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

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

33.  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.

34.  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.

35.  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.
 To increase the signal-to-noise ratio, the sequence was
repeated four times for each imaging.

36.  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.

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

38.  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.

39.  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.

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

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

44.  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.
 Reduce the extracellular
matrix and the diffusion
space of water protons in the
extracellular and
intracellular dimensions.

45.  The ADC of benign nodes (0.652 ± 0.101 × 10–3 mm2/sec).

46.  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.

47.  Negative prognostic factors were noted including:
A- Extra capsular spread (ECS).
B- Close or positive margins.
C- Peri-neural invasion.
D- Poor differentiation of tumor depth, and
the number of metastatic neck lymph nodes.

48.  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.

50.  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).

51.  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.