“EXPLORATION OF ULTRASONOGRAPHY (USG) AS AN ALTERNATIVE IMAGING MODALITY TO MAGNETIC RESONANCE IMAGING (MRI) IN DETECTION OF FACIAL SPACE SPREAD OF ODONTOGENIC INFECTIONS.”
BRIEF RESUME OF THE INTENDED WORKS
6.1 Need for the study:
Over the years, the introduction of techniques such as Ultrasonography (USG), computed tomography (CT) and magnetic resonance imaging (MRI) have revolutionized the field of diagnostic radiology. These powerful diagnostic tools have minimized the therapeutic dilemma for dental surgeons.
USG is relatively a new diagnostic aid in dentistry. The USG method could be considered to be quick, non-invasive, sensitive, widely available, inexpensive, and relatively painless.USG has been used to depict swellings, cysts, lymph nodes, salivary glands, vascular structures, and inflammatory masses in the head and neck region. USG could be very useful if repeated follow-up examinations required as it has no radiation exposure to patients.
In day to day practice evaluation of patients with acute odontogenic infections can be difficult for the dental surgeons, who have to deal with dilemma of whether there is an abscess, which requires surgical intervention or just cellulitis which can be managed satisfactorily with antimicrobial agents and supportive care. In these conditions USG is an effective diagnostic tool to confirm abscess formation and its exact anatomical location in the superficial facial spaces. Thus USG is very sensitive in detecting fluid collection as no echoes are returned by fluids.
MRI has been a gold standard for assessment of fascial space infections in the head and neck. The main advantages of MRI are its excellent tissue contrast and depiction of all anatomic planes without moving the patient. The major disadvantages of MRI were the prolonged time for image acquisition. As a result, the images may suffer from the effect of patient motion. The high static magnetic field also poses a danger to those individuals with cardiac pacemakers or neurostimulator units. It is also expensive and not widely available.
The purpose of this study is to explore the capability of Ultrasongraphy (USG) as an alternative imaging modality to magnetic resonance imaging (MRI) in analyzing facial space spread of odontogenic infections.
6.2 Review of literature:
A study was done on 16 patients with clinically diagnosed as odontogenic infections. They were examined with USG and MRI final diagnosis was confirmed by microbiologic analysis of specimen collected through percutaneous aspiration, incision, and drainage. They concluded that USG is effective method in detecting and staging spread of odontogenic infection to the superficial facial spaces.1 A study was done on 50 patients with acute odontogenic infections of the superficial facial spaces. Both radiographic and sonographic examinations, as well as needle aspiration were performed, purulent fluid was aspirated in 22 patients and 6 patients were diagnosed to have cellulitis, in 4 abscesses formation was diagnosed on the 3rd day. They concluded that Ultrasonography is an effective diagnostic tool to confirm abscess and is highly predictable in detecting the stage of infection.2 A study done on 8 patients for drainage of face and neck abscesses USG provided easy detection and accuracy for drainage. Which were difficult to locate on physical examination. Color Doppler USG added in differentiating blood vessels from the static space abscesses. Hence USG is a diagnostic tool in detection and treatment of superficial acute odontogenic facial space infections. 3 A study was done on 394 patients. USG examinations of head and neck were performed in all the 394 patients. Of these 87 percent of the patients had soft tissue swellings due to odontogenic infection. The other swellings originated from the skin and the salivary glands. The author concluded that USG is an inexpensive and noninvasive diagnostic technique, could be used in patients with inflammatory soft tissue swellings of many regions of head and neck.4 A study was done on 50 patients with infections involving the buccal and submandibular spaces. USG provided accurate information about the size of the abscess, as well as its depth from the surface marker. Thus the author concludes that USG is a safe, simple, and relatively inexpensive method of diagnosing the presence, exact location and dimensions of all abscesses in the orofacial area that are unobstructed by the bony structures. It avoids large, unsightly, postoperative facial scars and often eliminates the need for hospitalization.5 A study was carried out in 2 adult patients. In one case the abscess was associated with pericoronitis and the other with post extraction infection. In both the cases USG of lateral masticator space was done. Successful aspiration of pus was followed by an instantaneous improvement in ability to open the mouth. Thus the author concluded that USG can be beneficial in the management of orofacial infections.6
6.3 Objectives of the study:
To assess the capability of Ultrasonography (USG) as an alternative imaging modality to magnetic resonance imaging (MRI), in detection of facial space spread of odontogenic infections.
To correlate USG findings with those of MRI and to assess the role of USG in diagnosing superficial and deep facial space spread of odontogenic infections.
MATERIALS AND METHODS:
Source of data:
Patients visiting to the O.P.D of Oral Medicine and Radiology Department, Al-Badar Rural Dental College and Hospital Gulbarga, with acute facial swellings due to odontogenic infections.
7.2 Method of collection of data (including sampling procedure, if any)
Method of study:
The study group consists of 20 patients with acute odontogenic infections involving the facial spaces.
The subjects included were from all ages with no bar on gender.
All the patients clinically and radiographically diagnosed as odontogenic infections spreading to the facial spaces are included in the study.
Then the diagnosed patients will be subjected for USG and MRI of the affected area.
The linear array probe will be applied over the skin, covering the suspected area in transverse and axial sections to determine the presence or absence of fluid collection and its anatomical location.
All grey scale USG will be measured using on screen calipers. Ultrasound echogenicities will be described in comparison with adjacent tissues as follows; hyperechoic (brighter) isoechoic (equal) hypoechoic (darker) anechoic (no internal echoes) or mixed. These will be the key to stage the infections from acute phase to complete abscess formation as follows, if the echogenicities of the tissues are isoechoic similar to normal or uninfected site but increase in the fluid content it will be termed as edematous changes. If the echogenicities of the tissues is higher it will be termed as cellulitis. If it is mixed it will be termed as preabscess stage. If there is absence of echogenicities it will be termed as abscess stage.1
The MRI will be performed within 24 hours of USG. All the subjects will be scanned on a 1.5-t unit (Siemens). The imaging protocol included the axial and coronal planes.
A confirmatory microbiological analysis of specimens collected through percutaneous aspiration, incision and drainage will be carried out.
Specific statistical analysis will be carried out.
1. All the patients clinically diagnosed as odontogenic infections spreading
to the facial spaces are included in the study.
2. Patients of all ages with no sex bar are included.
3. Patients who are willing to participate in the study are included.
The cases with pathologies other than odontogenic infections are
excluded from the study.
The patients with contraindication to MRI.
Duration of the study: Two years from September 2009 to August 2011
7.3 Does the study require any investigations or interventions to be conducted on patients or other human or animals? If so describe briefly. Yes
I have been informed about the procedures of the study. The possible risks too have been explained to me. I have understood that I have the right to refuse my consent or withdraw it any time during the study without adversely affecting my treatment. I have been provided ample time to ask questions and I have clarified to my satisfaction. I am also aware that subjecting to this study, I will have to give more time for assessments by the doctor and these assessments do not interfere with the benefits. I,…………………………………………. the undersigned, give my consent to be a participant of this study.
SIGNATURE OF THE PATIENT/ SIGNATURE OF THE WITNESS/
THUMB IMPRESSION: NAME:
NAME: ADDRESS AND PHONE NUMBER:
ADDRESS AND PHONE NUMBER:
DESIGNATION OF THE DOCTOR:
Recommendations of the Ethical Committee
CERTIFICATE This is to certify that Dr. Sreenivas Ghali is a post graduate (MDS) student in the department of ORAL MEDICINE & RADIOLOGY admitted to this course during the academic year 2009. He/She has proposed the study topic titled-“ EXPLORATION OF ULTRASONOGRAPHY (USG) AS AN ALTERNATIVE IMAGING MODALITY TO MAGNETIC RESONANCE IMAGING (MRI) IN DETECTION OF FACIAL SPACE SPREAD OF ODONTOGENIC INFECTIONS”. To carry on the dissertation, the Ethical Committee has critically analyzed the methodology,
implications and expected complications of the study. It has been made mandatory to obtain
a written consent from the patients who volunteer to be included in the study. It necessitates
the conduct of the study under the strict supervision of the Guide & Head of the
Department, Oral Medicine & Radiology.
The Ethical committee is of the conscientious opinion that the proposed study can be
conducted without any legal, moral or ethical encumbrances.
Dr. Girish Katti MDS -