原文題目(出處)： MRI features of mandibular osteomyelitis: practical criteria based on an association with conventional radiography features and clinical classification
原文作者姓名：
Yoshiko Ariji, Masahiro Izumi, Masakazu Gotoh, Munetaka Naitoh, Mugio Katoh, Yuichiro Kuroiwa, Naofumi Obayashi, Kenichi Kurita, Kazuo Shimozato, Eiichiro Ariji,通訊作者學校：
AICHI-GAKUIN UNIVERSITY SCHOOL OF DENTISTRY AND MUGI DENTAL CLINIC報告者姓名(組別)： J 組 丁健民 報告日期： 97/05/12 內文：
Radiological examinations Diagnosis of mandibular osteomyelitis and evaluation of the response to treatment.
But limited in the acute stage because of low sensitivity.
Bone scintigraphy Depict increased uptake even in the acute stage
Low specificity in diagnosing as osteomyelitis
does not accurately identify the location of lesions.
Computed tomography (CT) Evaluation of bony changes Hardly depict bone marrow changes in the acute stage evaluate the early response to the treatment.
Magnetic resonance imaging (MRI) can well demonstrate the bone marrow changes caused by edema or inflammatory tissue due to increase of water content, which often replaces the normal fatty marrow in the acute stage.
This change of the bone marrow is shown as a low SI area on the T1-weighted image and a marked high SI area on T2-weighted or short TI inversion recovery (STIR) images
In the chronic stage, low SI area surrounded by high SI rim on both T1-weighted images and T2-weighted or STIR images.
Although MRI examination has the ability of early detection of osteomyelitis, but there is a relative dearth of reports regarding MRI diagnostic criteria applicable to each clinical stage of osteomyelitis.
The purposes of this study were
(1) To analyze the relationship between the imaging features of MRI and conventional techniques (2) To establish practical MRI diagnostic criteria in relation to the treatment and outcome
METHODS
Magnetic resonance imaging examinations were performed with a 1.0-T Magnex-100XP (Shimadzu, Kyoto, Japan) and a head coil. Standard MRI sequences were performed: spin-echo T1-weighted images and STIR images. The section thickness was 5.0 mm with an intersection gap of 1.0 mm. Axial and coronal images were obtained.
Prior to MRI examination, conventional radiographs were obtained for all subjects. Computed tomographic examination was added in 41 subjects. Scans were performed with a slice thickness of 2 or 3 mm, and the scan plane was parallel to the occlusal plane or inferior margin of the mandible.
Evaluation of imaging features
T1-weighted images were classified into 2 patterns: low and no change. The pathological changes of the bone marrow were evaluated by comparison with the SI of the contralateral side.
Low was defined as a decline in the SI of the bone marrow, and no change as a mild change or no change in the SI of the bone marrow.
Short T1 inversion recovery images were classified into 4 patterns: extensive high, focal high, low, and no change
Extensive high was defined as a strong and widespread increase in the SI of the bone marrow.
Focal high was a limited area increase in the SI. Low was defined as a decline in the SI of the bone marrow, and no change as a mild change or no change in the SI of the bone marrow.
Bony changes on conventional images were evaluated with reference to the CT appearance Lytic pattern was defined as having a feature that osteolysis was dominant.
Mixed pattern was a feature that osteosclerosis was combined with an equal or lesser amount of osteolysis.
Sclerotic pattern was a feature in which osteosclerosis was dominant.
Sequestrum pattern was a feature in which sequestration was seen with or without other bony changes.
Determination of the final diagnosis
The definitive diagnosis was confirmed by the pathological results or clinical course.
did not recur within the observation period.
In 5 subjects, symptoms disappeared once but recurred.
The remaining 1 subject was not cured by the treatment, but the pathological specimen obtained during surgical procedure verified the diagnosis of osteomyelitis.
In contrast, 8 subjects could not be diagnosed as osteomyelitis.
Of these, 3 subjects were prescribed carbamazepine or received stellate ganglion block, leading to the symptoms temporarily disappearing or being reduced.
In 3 subjects, the symptoms disappeared spontaneously within 2 months; their symptoms might have been due to localized periodontitis or the healing process after tooth extraction.
The remaining 2 subjects probably had mental problems, such as cancer phobia.
Relationship between MRI and conventional imaging features
Twenty-one subjects had low SI on T1-weighted imaging. Of these, 16 subjects had extensive high SI and 5 had focal high SI on T2-weighted or STIR imaging.
In 6 of these subjects, MRI appeared to be an effective tool for the diagnosis because there were no apparent bony changes on conventional radiography and CT
19 subjects had an extensive high, and 6 subjects had focal high SI on STIR imaging One subject showed low SI both on T1-weighted and STIR imaging
This appearance was characteristic in the chronic osteomyelitis.
Proposal of criteria for MRI
for the acute or subacute stage, the positive appearance of osteomyelitis is low SI on T1-weighted imaging, together with extensive high or focal high SI on T2-weighted or STIR imaging; for the chronic stage, appearance of low SI on both T1-weighted imaging and T2-weighted or STIR image is found.
features, which were also observed in one of the present cases, can be a characteristic feature in the chronic stage.
The STIR image is a recently introduced sequence .This technique enables us to evaluate T2 signals more easily with fat tissue suppression. Administration of gadolinium-DTPA may add very important information, such as a noncalcified periosteal reaction, definition of the limit of the sequestrum, and extension of the inflammation to soft tissue. These features were also detectable on STIR image, and therefore sequence with gadolinium-DTPA was not always used for making of MRI diagnostic criteria.
In conclusion, when osteomyelitis is suspected, especially for subjects without positive features of osteomyelitis on CT and conventional images, MRI with the 2 sequences, T1-weighted and
T2-weighted or STIR, used in this study should be performed.
題號 題目
1 下列何者並非造成 osteomyelitis 的原因 (A) Odontogenic infection
(B) Traumatic fracture (C) Chronic systemic disease (D) Radiation
答案(D) 出處：Oral and maxillofacial pathology 2nd P127~P128 題號 題目
2 何者並非 chronic osteomyelitis 的治療方法 (A) Drainage
(B) Curettage (C) Decortication (D) Hyperbaric oxygen
答案(A) 出處：Oral and maxillofacial pathology 2nd P127~P128
