Download To evaluate the efficacy of MRI in detection of cartilage invasion and

To evaluate the efficacy of MRI in detection of cartilage
invasion and submucosal space involvement in laryngeal
cancer for accurate pretherapeutic staging
Poster No.:
B-0396
Congress:
ECR 2014
Type:
Scientific Paper
Authors:
S. Priya , S. mehra ; NEW DELHI, NE/IN, New Delhi/IN
Keywords:
Ear / Nose / Throat, Interventional vascular, Musculoskeletal
joint, MR, MR-Diffusion/Perfusion, MR-Spectroscopy, Diagnostic
procedure, Staging, Surgery, Cancer, Neoplasia, Education and
training
DOI:
10.1594/ecr2014/B-0396
1
2 1
2
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Page 1 of 34
Purpose
Laryngeal carcinoma is the most common carcinoma of the upper aero digestive tract.
Most common site of its involvement is glottis [1] and squamous cell carcinoma is the
most common histopathological variant. [2] Fig. 1 on page 3
It presents commonly in the age group of 50-70 years with a strong male predominance.
Tobacco smoking and alcohol consumption are the most common risk factors responsible
for the rising incidence of laryngeal cancer. [3]
Adequate and accurate imaging is the most essential requirement for its early diagnosis
affecting the patient's management decisions.
Recently the role of open surgery has declined significantly because of more impetus
now on organ preservation, and thereby decreasing the patient's morbidity which is the
ultimate key for any physician treating a patient. [4-5]
A radiologist in his perspective and capacity has a significant role in the treatmentplanning by accurately diagnosing and staging the cancer, with special focus on
evaluating the deeper tissues i.e., cartilage and submucosal space involvement,
which the clinician is not able to evaluate endoscopically. [6-8]
Computed tomography has certain inherent limitations, one being its failure to
detect early cartilage invasion. It is because of large variability of ossification patterns
in laryngeal cartilage. Demonstrating tumour invasion of non-ossified cartilage is also
problematic with CT due to similarity of the CT density. [9]
Of all the other available imaging modalities, MRI has shown promising results in
its ability to detect intracartilaginous tumour spread and this detection is essential
for accurate pretreatment staging of laryngeal cancer. [10]
Hence present study was planned to compare the accuracy of MRI and CT in
detection of cartilage invasion and submucosal space involvement in laryngeal
cancer for accurate pretherapeutic staging.
Page 2 of 34
Images for this section:
Fig. 1: Reformatted post contrast coronal CT image (A) and post contrast enhanced
coronal MRI image (B) (red arrow) of a patient showing left glottis mass. Histopathological
image (C) of the same patient shows moderately differentiated Squamous cell carcinoma
with keratin pearls.
Page 3 of 34
Methods and materials
This study was conducted between December 2011 and February 2013 by the
Department of Radiodiagnosis in collaboration with the Department of Otorhinolaryngology, both at Post Graduate Institute of Medical Education and Research, Dr.
Ram Manohar Lohia Hospital, New Delhi, INDIA.
INCLUSION CRITERIA
All the patients who presented with features of hoarseness, pain, sore throat, dysphagia,
odynophagia, difficulty in breathing and neck masses were evaluated endoscopically,
and those suspected of having laryngeal carcinoma were referred for imaging evaluation
through MRI and CT.
EXCLUSION CRITERIA
Excluded from the study were all those patients in whom either satisfactory images were
not obtained due to motion artifacts, poor quality bone window and thick slices or where
both CT and MRI were not done.
SAMPLE SIZE
During the study period eighty-four patients presented with features of hoarseness,
dysphagia, odynophagia, sore throat, pain and neck mass. After endoscopic examination,
thirty-three patients were suspected of having laryngeal cancer and they were referred
for imaging evaluation by MRI and CT. Out of these thirty-three patients, nineteen
patients underwent surgery and were then evaluated for histopathological assessment.
The remaining fourteen patients were not assessed and were subjected to alternative
modes of treatment as shown in the consort flow diagram in figure 2.
Page 4 of 34
Fig. 2: CONSORT FLOW DIAGRAM
References: RADIODIAGNOSIS, DR. RML HOSPITAL, Postgraduate institute of
Medical Education and Research - NEW DELHI/IN
RADIOLOGICAL EXAMINATION
COMPUTED TOMOGRAPHY PROTOCOL
CT was performed using a 40-slice system. Contiguous axial sections of the neck were
obtained from the base of the skull to the thoracic inlet with slice thickness of 3 mm
with reformatted 1 mm soft tissue and bone window images in axial, sagittal and coronal
plane. Non-enhanced as well as contrast enhanced scan was performed sequentially
after intravenous administration of non-ionic contrast medium.
Multi-planar reconstruction and three-dimensional volume-rendering images were
created using the raw data of the first phase images.
Page 5 of 34
Additional Valsalva/phonation manoeuvers were used in selected cases to improve
visualization of certain anatomic areas, such as laryngeal ventricle and pyriform sinuses.
MAGNETIC RESONANCE IMAGING PROTOCOL
MRI was performed using 1.5 Tesla MR System. MR imaging of the larynx was done
using surface neck coils, keeping the slice thickness of 3-4 mm and 1 mm intersection
gap. The following sequences were included in the imaging protocol:
•
•
•
•
Axial, coronal and sagittal T1 weighted Fast spin echo
Axial, coronal and sagittal T2 weighted Fast spin echo
Fat sat axial T1w and T2w.
After i/v gadolinium-DTPA; post contrast axial, sagittal and coronal T1
weighted spin echo sequence.
IMAGE ANALYSIS
1. COMPUTED TOMOGRAPHY
A) SUBMUCOSAL SPACE INVOLVEMENT- Loss of fat plane with extention of soft tissue
mass was taken as positive for invasion of both pre epiglottic and paraglottic space.
B) CARTILAGE INVASION- The cartilages were evaluated using following criteria in
isolation and/or in combination:
THYROID CARTILAGE•
•
•
•
SCLEROSIS- Thickening of the ossified inner or outer cortex or as
increased ossification of the medullary cavity.
INVASION- Defined as destruction of the inner cortex of the thyroid cartilage
but preservation of the outer cortex.
PENETRATION- Patients who had tumour through both the inner and outer
thyroid cartilage were classified as having Penetration.
EXTRALARYNGEAL SPREAD- Defined as cartilage destruction with
tumour seen on the inner and outer aspect of a cartilage, including
involvement of extralaryngeal soft tissues.
CRICOID and ARYTENOID CARTILAGE•
SCLEROSIS- Thickening of the ossified inner or outer cortex or as
increased ossification of the medullary cavity.
Page 6 of 34
•
DESTRUCTION- combined both invasion and penetration. [11]
2. MAGNETIC RESONANCE IMAGING
A) SUBMUCOSAL SPACE INVOLVEMENT- Loss of fatty signal intensity on T1W images
with abnormal enhancing soft tissue seen on post contrast T1W images.
B) CARTILAGE INVASION ASSESSMENT- New imaging criteria as proposed by Becker
M et al for neoplastic cartilage invasion and cartilage inflammation were followed. [12]
PROPOSED NEW CRITERIA FOR CARTILAGE INVASION
OSSIFIED CARTILAGE
NON-OSSIFIED
CARTILAGE
T1W SPIN ECHO
LOW
LOW
T2W SPIN ECHO
SIMILAR TO THAT OF SIMILAR TO THAT OF
TUMOUR
TUMOUR
GADOLINIUM
ENHANCED T1W
ECHO
SIMILAR TO TUMOUR
SIMILAR TO TUMOUR
SPIN
CARTILAGE INFLAMMATION ACCORDING TO NEW CRITERIA
OSSIFIED CARTILAGE
NON-OSSIFIED
CARTILAGE
T1W SPIN ECHO
LOW
LOW
T2W SPIN ECHO
HIGHER THAN TUMOUR
HIGHER THAN TUMOUR
GADOLINIUM
ENHANCED T1W
ECHO
HIGHER THAN TUMOUR
HIGHER THAN TUMOUR
SPIN
HISTOPATHOLOGY- Out of a total of 33 patients 19 patients underwent surgery. The
surgical sample was assessed for its gross morphology, and evaluated for submucosal
space and hyaline cartilage invasion. Histopathological analysis was taken as the
standard and imaging results were correlated with histopathological assessment.
STATISTICAL ANALYSIS-
Page 7 of 34
Statistical analysis was performed using the SPSS statistical package (version 17.0).
Continuous variables were presented as mean ± SD, and categorical variables were
presented as absolute numbers and percentage. Categorical variables were analysed
using either the chi square test or Fisher's exact test. Sensitivity, specificity, Positive
predictive value (PPV) and Negative predictive value (NPV) were calculated to analyse
the diagnostic accuracy of MRI and CT.
P value less than 0.05 was taken as statistically significant difference.
TNM STAGING
TNM staging of laryngeal tumours was assigned in accordance with American Joint
Committee on Cancer. [13]
Images for this section:
Fig. 2: CONSORT FLOW DIAGRAM
Page 8 of 34
Results
Out of a total of eighty-four patients who presented with features of hoarseness,
dysphagia, odynophagia, sore throat, neck pain and neck masses, on endoscopic
examination thirty-three patients were suspected of having laryngeal cancer. These were
then referred for imaging evaluation by MRI and CT.
Out of these thirty-three patients, ten were excluded from the study as they refused to
undergo surgery and opted for chemoradiation. Three more patients could not be taken
up for surgery because of their poor general condition. One patient who was having
advanced disease with lung metastasis was also excluded from the study and was
subjected to chemoradiation.
The remaining nineteen patients who underwent surgery were then evaluated for
histopathological assessment.
Seventeen patients (89%) were males and remaining two (10%) were females. Most
common symptom of laryngeal carcinoma was hoarseness of voice and median age was
50-60 years.
Comparison of MRI and CT in evaluation of submucosal space involvement and
laryngeal cartilage invasion
MRI was more sensitive than CT in the detection of preepiglottic space (100% vs 80 %)
and paraglottic space invasion (94% vs 82%).
Page 9 of 34
Fig. 3: Axial CT image (A) of a patient shows loss of preepiglottic fat on left side
(red arrow) with T1W axial image of same patient (B) also showing obliteration of pre
epiglottic fat.
References: RADIODIAGNOSIS, DR. RML HOSPITAL, Postgraduate institute of
Medical Education and Research - NEW DELHI/IN
In our study we found MRI had a higher sensitivity in the detection of neoplastic
cartilage invasion than CT. The sensitivity and specificity of MRI in cartilage invasion
were as follows: thyroid cartilage (91.7% vs 71.4%); cricoid cartilage (100% vs 67%) and
in arytenoid cartilage (92% vs 71%).
Page 10 of 34
Fig. 4: T1W axial (A) and reformatted coronal CT image (B) of the same patient shows
obliteration of left paraglottic space (red arrow).
References: RADIODIAGNOSIS, DR. RML HOSPITAL, Postgraduate institute of
Medical Education and Research - NEW DELHI/IN
The sensitivity of CT in cartilage invasion detection was 75% in thyroid cartilage, 71.4%
in cricoid cartilage and 83% in arytenoid cartilage. The corresponding specificities in
detection of cartilage invasion were 86% in thyroid cartilage, 83.3% in cricoid cartilage
and 85.7% in arytenoid cartilage.
Page 11 of 34
Fig. 5: Axial post contrast soft tissue (A) and bone window (B) CT image of a patient
with left sided laryngeal mass shows invasion of left thyroid cartilage (red arrow). Axial
T1W image of the same patient (C) shows hypointense signal in the posterior lamina
of left thyroid cartilage (red arrow). Axial T2W image (D) shows posterior part of left
thyroid cartilage to be of same signal as that of the primary tumour (red arrow).Post
contrast image (E) shows similar enhancement as that of tumour suggestive of
cartilage invasion(red arrow).Extralaryngeal spread with involvement of strap muscles
is shown on left side (blue arrow). The finding was confirmed on histopathology as
shown in (F) showing thyroid cartilage infiltration (black arrow).
References: RADIODIAGNOSIS, DR. RML HOSPITAL, Postgraduate institute of
Medical Education and Research - NEW DELHI/IN
On histopathological correlation of the resected specimen with MRI two patients were
false positive for thyroid cartilage invasion with only one false negative patient. For cricoid
cartilage invasion there were four false positives. Two patients were wrongly estimated
for the involvement of arytenoid cartilage while only one patient with arytenoid cartilage
involvement was not detected and was missed by MRI.
Page 12 of 34
Fig. 6: Axial CT scan of a patient with soft tissue (A) and bone window (B) image
showing sclerosis of left cricoid cartilage (red arrow). In T1W axial image (C) of the
same patient there is hypointense signal in the left side of cricoid cartilage (red arrow)
which appears isointense to tumour on T2W image (D) and shows enhancement
similar to tumour on post contrast image (E) suggestive of tumour involvement. This
was further confirmed on histopathology (black arrow) as shown in image (F).
References: RADIODIAGNOSIS, DR. RML HOSPITAL, Postgraduate institute of
Medical Education and Research - NEW DELHI/IN
On correlation of CT with postoperative histopathological findings it was shown that one
patient showed false positive and three patients showed false negative results for thyroid
cartilage involvement. Two patients each had false positive and false negative results for
detection of cricoid cartilage involvement while one patient was found to be false positive
for arytenoid cartilage involvement with two false negative results.
Page 13 of 34
Fig. 7: Post contrast axial CT with soft tissue window (A) image in a patient with right
glottic mass shows sclerotic right arytenoid cartilage (blue arrow). Axial T1W image
(B) shows intermediate signal intensity in right arytenoid cartilage (blue arrow) and
T2W image (C) shows signal in the cartilage to be isointense to that of tumour. Post
contrast axial T1W image (D) shows similar enhancement to tumour and engulfment of
right arytenoid cartilage by the tumour. Extralaryngeal spread with involvement of strap
muscles on right side is clearly depicted on post gadolinium contrast enhanced images
(red arrow).
References: RADIODIAGNOSIS, DR. RML HOSPITAL, Postgraduate institute of
Medical Education and Research - NEW DELHI/IN
The detailed results are documented in Table 1 on page 22
SENSITIVITY SPECIFICITY PPV
(%)
(%)
(%)
NPV (%)
ACCURACY
(%)
93
90
Pre Epiglottic Space (PES) Involvement
CT
80
93
80
Page 14 of 34
MRI
100
93
83
100
95
Para Glottic Space (PGS) Involvement
CT
82
100
100
40
84
MRI
94
100
100
67
95
Thyroid Cartilage (TC) Involvement
CT
75
86
90
67
79
MRI
92
71
85
83
89
Cricoid Cartilage (CC) Involvement
CT
71
83
71
83
79
MRI
100
67
64
100
79
Arytenoid Cartilage (AC) Involvement
CT
83
86
91
75
79
MRI
92
71
85
83
84
Staging of carcinoma (T3 & T4)
CT
60
86
60
86
73
MRI
80
93
80
93
90
MRI was more accurate than CT in detecting preepiglottic and paraglottic space invasion
and also in the detection of laryngeal cartilage invasion. The diagnostic accuracy of MRI
in terms of staging was high in comparison to CT (90% vs 73%).
The comparison of CT and MRI in terms of accuracy is depicted in Figure 8.
Page 15 of 34
Fig. 8: Accuracy chart of CT and MRI in detection of submucosal space involvement
and laryngeal cartilage invasion. MRI is highly accurate as compared to CT as being
shown here.
References: RADIODIAGNOSIS, DR. RML HOSPITAL, Postgraduate institute of
Medical Education and Research - NEW DELHI/IN
MRI was statistically more significant than CT in the staging of laryngeal cancer
(p 0.006 vs 0.08) and also in the detection of paraglottic space invasion (p 0.017
vs 0.05).
In statistical terms no significant difference was observed between MRI and CT in the
detection of pre epiglottic space (p 0.001 vs 0.006). MRI and CT were statistically
insignificant in the detection of laryngeal cartilage invasion; thyroid cartilage (p 0.01 vs
0.02); cricoid cartilage (p 0.012 vs 0.045); and arytenoid cartilage (p 0.01 vs 0.006).
The results are displayed in Table 2 on page 24
Page 16 of 34
POSITIVE
[n(%)]
NEGATIVE
P VALUE
[n(%)]
Pre
Epiglottic
Space 5
Histopathological examination
(HPE)
14
-
CT
0.006
positive
4 (80)
1 (7)
negative
1 (20)
13 (93)
positive
5 (100)
1 (7)
negative
-
13 (93)
Paraglottic Space (HPE)
17
2
-
CT
positive
14 (82)
-
0.05
negative
3 (18)
2 (100)
positive
16 (94)
-
negative
1 (6)
2 (100)
Thyroid Cartilage (HPE)
12
7
-
CT
positive
9 (75)
1 (14)
0.02
negative
3 (25)
6 (86)
positive
11 (92)
2 (29)
negative
1 (8)
5 (71)
Cricoid Cartilage (HPE)
7
12
-
CT
positive
5 (71)
2 (17)
0.045
negative
2 (29)
10 (83)
positive
7 (100)
4 (33)
negative
-
8 (67)
Arytenoid Cartilage (HPE)
12
7
-
CT
positive
10 (83)
1 (14)
0.006
negative
2 (17)
6 (86)
positive
11 (92)
2 (29)
negative
1 (80
5 (71)
T3 : 5
T4 : 14
-
positive
3 (60)
2 (14)
0.08
negative
2 (40)
12 (86)
MRI
MRI
MRI
MRI
MRI
STAGING (HPE)
CT
0.001
0.017
0.01
0.012
0.01
Page 17 of 34
MRI
positive
4 (80)
1 (7)
negative
1 (20)
13 (93)
0.006
Images for this section:
Fig. 3: Axial CT image (A) of a patient shows loss of preepiglottic fat on left side (red
arrow) with T1W axial image of same patient (B) also showing obliteration of pre epiglottic
fat.
Page 18 of 34
Fig. 4: T1W axial (A) and reformatted coronal CT image (B) of the same patient shows
obliteration of left paraglottic space (red arrow).
Page 19 of 34
Fig. 5: Axial post contrast soft tissue (A) and bone window (B) CT image of a patient
with left sided laryngeal mass shows invasion of left thyroid cartilage (red arrow). Axial
T1W image of the same patient (C) shows hypointense signal in the posterior lamina
of left thyroid cartilage (red arrow). Axial T2W image (D) shows posterior part of left
thyroid cartilage to be of same signal as that of the primary tumour (red arrow).Post
contrast image (E) shows similar enhancement as that of tumour suggestive of cartilage
invasion(red arrow).Extralaryngeal spread with involvement of strap muscles is shown
on left side (blue arrow). The finding was confirmed on histopathology as shown in (F)
showing thyroid cartilage infiltration (black arrow).
Page 20 of 34
Fig. 6: Axial CT scan of a patient with soft tissue (A) and bone window (B) image showing
sclerosis of left cricoid cartilage (red arrow). In T1W axial image (C) of the same patient
there is hypointense signal in the left side of cricoid cartilage (red arrow) which appears
isointense to tumour on T2W image (D) and shows enhancement similar to tumour on
post contrast image (E) suggestive of tumour involvement. This was further confirmed on
histopathology (black arrow) as shown in image (F).
Page 21 of 34
Fig. 7: Post contrast axial CT with soft tissue window (A) image in a patient with right
glottic mass shows sclerotic right arytenoid cartilage (blue arrow). Axial T1W image
(B) shows intermediate signal intensity in right arytenoid cartilage (blue arrow) and
T2W image (C) shows signal in the cartilage to be isointense to that of tumour. Post
contrast axial T1W image (D) shows similar enhancement to tumour and engulfment of
right arytenoid cartilage by the tumour. Extralaryngeal spread with involvement of strap
muscles on right side is clearly depicted on post gadolinium contrast enhanced images
(red arrow).
Page 22 of 34
Table 1: Comparison of CT and MRI in detection of submucosal spaces and laryngeal
cartilage invasion with their respective sensitivity, specificity, positive and negative
predictive values showing MRI being highly sensitive as compared to CT.
Page 23 of 34
Fig. 8: Accuracy chart of CT and MRI in detection of submucosal space involvement and
laryngeal cartilage invasion. MRI is highly accurate as compared to CT as being shown
here.
Page 24 of 34
Table 2: P value charting of CT and MRI. MRI is significant in terms of staging of laryngeal
cancer.
Page 25 of 34
Conclusion
Imaging has become an indispensable tool for characterization and staging of laryngeal
cancer. Nevertheless, an ideal method for the detection of laryngeal cartilage and
submucosal space involvement for accurate pretherapeutic staging is still being awaited.
COMPARISON OF MRI AND CT IN INVOLVEMENT OF SUBMUCOSAL SPACE
We observed that MRI was more sensitive than CT in the detection of both preepiglottic
space (100% vs 80%) and paraglottic space (94% vs 82%) invasion. MRI was statistically
more significant as compared to CT in the detection of paraglottic space involvement (p
0.017 vs 0.05). MRI also had fewer false negatives as compared to CT.
No significant difference was found between MRI and CT in the detection of preepiglottic
space invasion (p 0.001 vs 0.006).
MRI was definitely more accurate than CT in detection of preepiglottic space (95%
vs 90%) and paraglottic space invasion (95% vs 84%).
Our results were contrary to the findings of Zbaren P et al [14-15] that reported no
significant statistical difference between CT and MRI in detecting submucosal space
invasion by the tumour since we found MRI to be more significant than CT in the detection
of paraglottic space invasion.
COMPARISON OF MRI AND CT IN INVOLVEMENT OF NEOPLASTIC CARTILAGE
INVOLVEMENT
We showed that MRI had a higher sensitivity and greater accuracy in the detection of
neoplastic cartilage invasion with few false negatives. On the other hand CT showed
poor sensitivity and more false negative cases.
The sensitivity of CT was low because sclerosis may be associated with the
normal ossification process. In some cases the sclerosis could have been due to
the peritumoral reactive inflammatory changes within the cartilage and not because of
actual neoplastic infiltration of the cartilage as it was confirmed on histopathological
examination. Further due to wide variation in the ossification of laryngeal cartilages, it
was technically difficult to comment on erosion or invasion of cartilages as shown in figure
9 (this could have led to false negative cases on the higher side).
Page 26 of 34
Fig. 9: Axial post contrast CT of a patient with left glottis mass (A) shows normal
appearing thyroid cartilage (blue arrow) with no evidence of cartilage erosion/invasion
on bone window (B). T1W axial (C) image of the same patient shows low signal of
the posterior lamina of left thyroid cartilage with isointense signal (blue arrow) seen
on T2W image (D). Post gadolinium contrast enhanced image (E) show cartilage
enhancement similar to that of tumour (arrow) suggestive of cartilage invasion. This
was subsequently confirmed on histopathology as shown in image (F) showing tumour
cells infiltrating thyroid cartilage (black arrow).
References: RADIODIAGNOSIS, DR. RML HOSPITAL, Postgraduate institute of
Medical Education and Research - NEW DELHI/IN
Our study was in agreement with previous studies, concluding that CT imaging alone
clearly has limitations in deciding cartilage invasion or erosion [11,16] and also proving
the higher sensitivity and greater accuracy of MRI in comparison to CT imaging for
cartilage invasion. [9,13,14,17]
COMPARISON OF MRI AND CT FOR DIAGNOSTIC ACCURACY IN STAGING OF
LARYNGEAL CANCER
Page 27 of 34
MRI had very high accuracy as compared to CT in staging of laryngeal cancer (89% vs
73%). The staging of laryngeal cancer was statistically more significant in MRI than in CT
(p 0.006 vs 0.08). This could be due to more false negative results in cartilage invasion
detection in CT as compared to MRI.
Our results are in consonance with the previously published literature which reported MRI
to be highly accurate and superior to CT for the staging of laryngeal cancer due to the
former's high sensitivity in detection of laryngeal cartilage invasion, better assessment of
pre epiglottic and paraglottic space involvement, excellent soft tissue differentiation and
multiplanar representation capability. [14, 18-20]
LIMITATIONS
One of the main limitations of our study was a small sample size (n=19) since out of a
total of 33 patients, 14 opted for radiotherapy and only remaining 19 patients could be
subjected to histopathological assessment.
MR imaging had a few more false positive cases of cartilage invasion as compared to CT
imaging. This was due to the high sensitivity of MRI in detecting signal intensity alterations
in the cartilaginous matrix compared to CT. This high sensitivity might have resulted in
the reactive peritumoral inflammation being reported as neoplastic involvement leading
to some false positive cases as shown in figure 10.
Page 28 of 34
Fig. 10: Peritumoral inflammation mimicking as cartilage invasion- Axial T2W image
(A) of the patient with left glottic mass shows hyperintense signal to the tumour in
posterior lamina of thyroid cartilage (blue arrow) with post contrast image (B) showing
more enhancement as compared to tumour mimicking cartilage invasion.
References: RADIODIAGNOSIS, DR. RML HOSPITAL, Postgraduate institute of
Medical Education and Research - NEW DELHI/IN
IMPLICATIONS FOR FUTURE RESEARCH
A large prospective study (adequately powered) is required to finally confirm the benefit of
MRI over CT in the detection of deep mucosal spaces, cartilage invasion and preoperative
assessment of laryngeal cancer for staging and prognosis.
SUMMARY
•
MRI offers higher staging accuracy as compared to CT (89.5 vs 78.9%)
with better and early characterization of laryngeal cartilage invasion.
Page 29 of 34
•
•
•
•
•
•
•
MRI is more sensitive than CT for detection of cartilage invasion with
fewer false negatives.
Upon using new established criteria of cartilage invasion, the
specificity of MRI has improved.
Gadolinium enhanced images improve margins of the tumour and fat
suppression techniques improve the conspicuity of involvement of
fatty tissue in the paralaryngeal submucosal spaces.
MRI provides better soft tissue resolution and multiplanar imaging.
Criteria used in CT for cartilage invasion detection like sclerosis,
erosion/invasion suffered from high variability in the ossification of
cartilages and this makes it difficult to comment upon the cartilage
invasion.
CT has more number of false negatives in cartilage invasion and this
can affect treatment strategy.
CT has very poor contrast resolution.
RECOMMENDATIONS
We recommend MRI to be used as a first line investigation modality for evaluation of
laryngeal cancer patients.
Images for this section:
Page 30 of 34
Fig. 9: Axial post contrast CT of a patient with left glottis mass (A) shows normal
appearing thyroid cartilage (blue arrow) with no evidence of cartilage erosion/invasion
on bone window (B). T1W axial (C) image of the same patient shows low signal of the
posterior lamina of left thyroid cartilage with isointense signal (blue arrow) seen on T2W
image (D). Post gadolinium contrast enhanced image (E) show cartilage enhancement
similar to that of tumour (arrow) suggestive of cartilage invasion. This was subsequently
confirmed on histopathology as shown in image (F) showing tumour cells infiltrating
thyroid cartilage (black arrow).
Page 31 of 34
Fig. 10: Peritumoral inflammation mimicking as cartilage invasion- Axial T2W image (A)
of the patient with left glottic mass shows hyperintense signal to the tumour in posterior
lamina of thyroid cartilage (blue arrow) with post contrast image (B) showing more
enhancement as compared to tumour mimicking cartilage invasion.
Page 32 of 34
Personal information
Sarv Priya, Post graduate student (MD)
Department of Radiodiagnosis, PGIMER, DR. RML HOSPITAL, NEW DELHI, INDIA.
[email protected]
Shibani Mehra, DNB
Associate Professor
Department of Radiodiagnosis, PGIMER, DR. RML HOSPITAL, NEW DELHI, INDIA.
[email protected]
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