SYNOPSIS

DR. SANDEEP R.

post graduate student

department of oral medicine and radiology

VALUE OF MRI FINDINGS IN DIAGNOSIS OF ODONTOGENIC TUMORS. A CROSSECTIONAL STUDY.

A.E.C.S. MAARUTI COLLEGE OF DENTAL SCIENCES AND RESEARCH CENTRE, BANGALORE.

2013 – 2016

Rajiv Gandhi University of Health Sciences, Karnataka

Bangalore

ANNEXURE II

PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION

1. / Name of the Candidates and Address / Dr. SANDEEP R.
I yr POST GRADUATE STUDENT
DEPARTMENT OF ORAL MEDICINE AND RADIOLOGY
A E C S MAARUTI COLLEGE OF DENTAL SCIENCES AND RESEARCH CENTRE, BANGALORE
2. / Name of the institution / A. E. C. S. MAARUTI COLLEGE OF DENTAL SCIENCES AND RESEARCH CENTRE, BANGALORE
3. / Course of study and subject / MASTER OF DENTAL SURGERY
ORAL MEDICINE AND RADIOLOGY
4. / Date of admission to course / 30/05/2013
5. / Title of the topic:
VALUE OF MRI FINDINGS IN DIAGNOSIS OF ODONTOGENIC TUMORS– A CROSS-SECTIONAL STUDY
6. / BRIEF RESUME OF THE INTENDED WORK
6.1 NEED FOR THE STUDY:
Odontogenic tumors comprise a large heterogeneous group of lesions originating from the epithelium and/or odontogenic ectomesenchyme and remnants. Odontogenic tumors include entities of a hamartomatous nature, such as odontoma, benign neoplasms, some of which are aggressive in behavior as is the case with ameloblastoma, odontogenic myxoma, and malignant neoplasms capable of metastasis. Odontogenic keratocysts have recently been included in the WHO classification of odontogenic tumors as keratocystic odontogenic tumors on account of their clinical behavior and genetic and molecular features.
Frequently odontogenic tumors do not display any radio-opaque foci on radiographs, and odontogenic tumors with large soft-tissue components can also display similar findings. Therefore, it is difficult for radiologists to distinguish between odontogenic tumors with radiolucent areas, which frequently occur in the jawbones.
MRI, which possesses superior soft-tissue contrast, is a useful imaging modality for diagnosing tumors with soft-tissue components. MRI has been proven to be useful for the differential diagnosis of odontogenic tumors. The aim of this study is to evaluate the diagnostic value of MRI, in diagnosis of odontogenic tumors.
6.2REVIEW OF LITERATURE:
1) A study was done on 51 patients diagnosed with odontogenic tumors were subjected to preoperativeMRI examinations. For tumors with liquid components, i.e. ameloblastomas andkeratocystic odontogenic tumors (KCOTs), the signal intensity (SI) uniformity of their cysticcomponents (U) was calculated and then their U values were compared. For tumors withsolid components that had been examined using dynamic contrast-enhanced MRI (DCEMRI),their CImax (maximum contrast index), Tmax (the time when CImax occurred), CIpeak(CImax30.90), Tpeak (the time when CIpeak occurred) and CI300 (i.e. the CI observed at 300 safter contrast medium injection) values were determined from CI curves. They then classified theodontogenictumors according to their DCE-MRI parameters. The results showed Significant differences between the U values of the ameloblastomas and KCOTwere observed on T1 weighted images, T2 weighted images and short TI inversion recoveryimages. They concluded that Cystic component SI uniformity was found to be useful for differentiatingbetween ameloblastomas and KCOT. However, the DCE-MRI parameters of odontogenic tumors, except for odontogenic fibromas and odontogenic myxomas, contributed little totheir differential diagnosis.
2) A study was done on 9 patients with ameloblastoma and 7 patients with keratocystic odontogenic tumors using diffusion-weighted MR imaging. Apparent diffusion co-efficients (ADCs) of the non-enhancing and solid lesions in these tumors were determined with use of 2 b factors (500 and 1000). The study showed that two types of non-enhancing lesions were identified, one with high signal intensity on fat-suppressed T2-weighted images (type A) and the other with low or intermediate intensity (type B). The type A non-enhancing lesions were observed in all the ameloblastomas, but they were evident in only 2 keratocystic odontogenic tumors. They found it interesting to note that the ADCs of the non-enhancing lesions in the ameloblastomas were significantly higher than those of the non-enhancing lesions in the keratocystic odontogenic tumors. The ADCs of the solid lesions in the ameloblastomas were significantly lower than those of the non-enhancing lesions in the ameloblastomas and were similar to those of the non-enhancing lesions in the keratocystic odontogenic tumors. The authors concluded that diffusion weighted MR imaging is a useful adjunct tool for the differentiation between ameloblastomas and keratocystic odontogenic tumors.
3) A study was conducted to retrospectively evaluate magnetic resonance images (MRI) and dynamic contrast-enhanced MRI (DCE-MRI) of ameloblastomas. MRI and DCE-MRI were performed for 10 ameloblastomas.The authors obtained the following results from the MRI and DCE-MRI. (a) Ameloblastomas can be divided into solid and cystic portions on thebasis of MR signal intensities. (b) Ameloblastomas show a predilection for intermediate signal intensity on T1WI, high signal intensity onT2WI, and well enhancement in the solid portion; they also show a homogeneous intermediate signal intensity on T1WI and homogeneoushigh signal intensity on T2WI, and no enhancement in the cystic portion. (c) The mural nodule or thick wall can be detected in ameloblastomaslesions. (d) Contrast index (CI) curves of ameloblastomas show two patterns: the first pattern increases, reaches a plateau at 100–300 s, then sustains the plateauor decreases gradually to 600–900 s, while the other increases relatively rapidly, reaches a plateau at 90–120 s, then decreases relatively rapidlyto 300 s, and decreases gradually thereafter. There was no difference in the CI curve patterns among primary and recurrent cases, a case withglandular odontogenic tumor in ameloblastoma or among histopathological types such as plexiform, follicular, mixed, desmoplastic, andunicystic type.
4) A study was done to evaluate the usefulness of contrast enhanced MRI to differentiate unilocular ameloblastoma from radiographically similar pathologies such as odontogenic keratocyst or a dentigerous cyst. Contrast enhanced MRI was performed on 13 cases of unilocular, round radiolucent lesions, visualized on panoramic radiograph and/ or CT. in case of unilocular ameloblastoma T1-weighted images showed low signal intensity and T2- weighted images showed high signal intensity, also a relatively thick rim-enhancement with/without small intraluminal nodules was observed upon CE_T1W images. CE-MRI was considered useful in diagnosis of unilocular ameloblastoma, as the characteristic features of UA ie., (thick enhancement of tumor wall and small intraluminal nodules were detected by CE-MRI.
5) A study was done to evaluate whether contrast-enhanced (CE)-T1WI and dynamic CE-MRI (DCE-MRI) could provide additional information for differential diagnosis in unilocular cystic-type ameloblastoma. Images from 12 cases of suspected unilocular cystic-type ameloblastoma were evaluated. Of them, 5 had areas suspected of indicating a solid component on T1WI and T2WI (or STIR). Ten had undergone additional CE-T1WI and DCE-MRI. On 5 of 10 cases of CE-T1WI, a tiny enhancement area was detected. On 6 of 10 DCE-images, a time-course enhanced area which was suspected to be a solid component was detected. CE-T1WI was helpful in the diagnosis of ameloblastoma because the tiny enhanced areas were taken to indicate possible solid components. Moreover, the rim-enhancement area on CE-T1WI could be divided into small regions of interest, and some of these showed slightly increased enhancement on DCE-MRI, which was taken to indicate a solid component and/or intramural nodule with focal invasion of ameloblastoma tissue. Thus CE-T1W1 and DCE-MRI were helpful in the differential diagnosis of unilocular cystic-type ameloblastomas with homogenously bright high signal intensity on T2W1 or STIR.
6.3 OBJECTIVES OF THE STUDY:
1) To evaluatethe diagnostic value of MRI, in diagnosis of odontogenic tumors.
2) To identify the presence or absence of cystic contents in odontogenic tumors.
3) To evaluate the interface between hard and soft components of odontogenic tumors.

7. MATERIALS AND METHODS

7.1 SOURCE OF DATA
Patients (both in and out-patients) reporting to the Department of Oral Medicine and Radiology, A. E. C. S. MAARUTI COLLEGE OF DENTAL SCIENCES AND RESEARCH CENTRE, BANGALORE
STUDY DESIGN:
The study will be a cross-sectional study.
SAMPLE SIZE
A total number of 25 patients will be included in the study.
7.2 METHOD OF COLLECTION OF DATA
Patients reporting to the department of Oral Medicine and radiology, A.E.C.S. Maaruti Dental College, who have been diagnosed radiologically and histopathologically as odontogenic tumors,will be interviewed and relavent clinical data will be collected. A semi-structured proforma will be developed for the purpose of data collection. All relevant details will be noted in the proforma. Informed consent will be obtained.
INCLUSION CRITERIA
  1. Patients who have already been diagnosed of odontogenic tumors radiologically and histopathologically.
EXCLUSION CRITERIA
  1. Presence of other medical or psychiatric co-morbidity (life-time/current)
  2. Presence of other malignancies of non-odontogenic origin
  3. Patient giving history of claustrophobia
  4. Insulin pumps
  5. Ferromagnetic implants or devices, which may be affected or may cause artifacts in the image.

METHODOLOGY:
Patients satisfying inclusion criteria will be requested for their participation in this study. Consented patients will undergo an MRI scan of the affected regions using a 1.5 Tesla machine.The images will be assessed for diagnostic value in diagnosing odontogenic tumors, presence of cystic, soft and hard tissue components of the tumors and also to differentiate between ameloblastomas and keratocystic odontogenic tumors. This data will be analyzed and interpreted.
7.3 Does the study require any investigation or interventions to be conducted on patients or other human or animals? If so, please describe briefly
The patient will be required to undergo a noninvasive MRI scan of the region/ regions under study.
7.4 Has the ethical clearance obtained from your institution in case of 7.3?

8. LIST OF REFERENCE ARTICLES:

8.1JOURNAL REFERENCES:
1.M Fujita, H Matsuzaki, Y Yanagi, M Hara, N Katase, M Hisatomi, T Unetsubo, H Konouchi, H Nagatsuka3 and J I Asaumi Diagnostic value of MRI for odontogenic tumours, Dentomaxillofac Radiol 2013; 42
2.M. SumiY. IchikawaI. KatayamaS. TashiroT. Nakamura Diffusion-Weighted MR Imaging of Ameloblastomas and Keratocystic Odontogenic Tumors: Differentiation by Apparent Diffusion Coefficients of Cystic Lesions, Am J Neuroradiol 2008; 29: 1897-901
3.Jun-ichi Asaumi, Miki Hisatomi, Yoshinobu Yanagi, Hidenobu Matsuzaki, Yong Suk Choi, Noriko Kawai, Hironobu Konouchi, Kanji Kishi Assessment of ameloblastomas using MRI and dynamic contrast-enhanced MRI, European Journal of Radiology 2005; 56: 25-30
4.Hironobu Konouchi, Jun-ichi Asaumi , Yoshinobu Yanagi, Miki Hisatomi, Noriko Kawai, Hidenobu Matsuzaki, Kanji Kishi Usefulness of contrast enhanced-MRI in the diagnosis of unicystic ameloblastoma, Oral Oncology 2006; 42: 481-486
5.Miki Hisatomi , Yoshinobu Yanagi , Hironobu Konouchi , Hidenobu Matsuzaki , Toshihiko Takenobu , Teruhisa Unetsubo , Jun-ichi Asaumi Diagnostic value of dynamic contrast-enhanced MRI for unilocular cystic-type ameloblastomas with homogeneously bright high signal intensity on T2-weighted or STIR MR images. Oral Oncology 2011; 47: 147-152
9.SIGNATURE OF THE CANDIDATE
10. REMARKS OF THE GUIDE
11. NAME AND DESIGNATION OF (IN BLOCK LETTERS)
11.1 GUIDE:
11.2 SIGNATURE / Dr. SATHEESHA REDDY B.H.M.D.S
PROFESSOR and HOD,
DEPARTMENT OF ORAL MEDICINE AND RADIOLOGY,
A.E.C.S. MAARUTI COLLEGE OF DENTAL SCIENCES & RESEARCH CENTRE, BANGALORE
11.3CO-GUIDE IF ANY:
11.4 SIGNATURE: / Dr. RAMAMURTHY T.K M.D.S
PROFESSOR,
DEPARTMENT OF ORAL MEDICINE AND RADIOLOGY,
A.E.C.S. MAARUTI COLLEGE OF DENTAL SCIENCES & RESEARCH CENTRE, BANGALORE
11.5 HEAD OF THE DEPARTMENT
11.6 SIGNATURE
12. REMARKS OF THE CHAIRMAN AND PRINCIPAL / DR. SATHEESHA REDDY.B H M.D.S
PROFESSOR AND H.O.D,
DEPARTMENT OF ORAL MEDICINE AND RADIOLOGY,
A.E.C.S. MAARUTI COLLEGE OF DENTAL SCIENCES & RESEARCH CENTRE, BANGALORE
12.1 SIGNATURE OF THE CHAIRMAN AND PRINCIPAL

CONSENT FORM

I, aged ______years on my own volition hereby give my consent to be a part of the comparative study conducted by Dr. Sandeep R., Post Graduate student, Department of Oral Medicine and Radiology, A.E.C.S. MAARUTI COLLEGE OF DENTAL SCIENCES & RESEARCH CENTRE, BANGALORE.

I have been explained in the language known to me about the clinical procedure and I understand that the study includes examination of intraoral changes.

I have given my consent to use this information and assessment for the purpose (research, publication or oral presentation) as deemed fit.

Date :

Place:

Patient’s Signature

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