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.