Comparison of dynamic susceptibility contrast enhanced MR and FDG-PET brain studies in patients with Alzheimer's disease and amnestic mild cognitive impairment.

BACKGROUND: The aim of this study was to compare Dynamic Susceptibility Contrast Enhanced MRI (DSC-MRI) and PET with [18F]flurodeoxyglucose (FDG-PET) in the diagnosis of Alzheimer's Disease (AD) and amnestic Mild Cognitive Impairment (aMCI). METHODS: Twenty-seven age-and sex-matched patients with AD, 39 with aMCI and 16 controls underwent brain DSC-MRI followed by FDG-PET. Values of relative Cerebral Blood Volume (rCBV) and rCBV z-scores from frontal, temporal, parietal and PCG cortices were correlated with the rate of glucose metabolism from PET. Sensitivity, specificity and accuracy of DSC-MRI and FDG-PET in the diagnosis of AD and aMCI were assessed and compared. RESULTS: In AD, hypoperfusion was found within all the examined locations, while in aMCI in both parietal and temporal cortices and left PCG. FDG-PET showed the greatest hypometabolism in parietal, temporal and left PCG regions in both AD and aMCI. FDG-PET was more accurate in distinguishing aMCI from the controls than DSC-MRI. In the AD and combined group (AD + aMCI) there were numerous correlations between DSC-MRI and FDG-PET results. CONCLUSIONS: In AD the patterns of hypoperfusion and glucose hypometabolism are similar, thus DSC-MRI may be a competitive method to FDG-PET. FDG-PET is a more accurate method in the diagnosis of aMCI.

Odontogenic inflammatory processes of head and neck in computed tomography examinations.

BACKGROUND: Infections of odontogenic origin are the most common cause of inflammatory disease of head and neck region. Computed tomography allows for defining localization and extent of inflammatory lesions, visualizes soft tissue involvement, presence of an abscess or an osteolytic lesion around causative tooth. THE AIM OF THIS STUDY WAS TO ASSESS PATHWAYS, BY WHICH ODONTOGENIC INFECTIONS SPREAD INTO RESPECTIVE DEEP HEAD AND NECK STRUCTURES IN COMPUTED TOMOGRAPHY EXAMINATION, TAKING INTO ACCOUNT THE FOLLOWING CRITERIA: frequency of involvement of respective deep cervical spaces, possibility to determine a probable causative tooth and concordance with the results of clinical examination. MATERIAL/METHODS: Thirty-eight patients cervicofacial inflammatory disease had undergone CT examination of head and neck region with a 64-slice CT scanner after intravenous contrast administration. RESULTS: Abscess was reported in 30 (79%) cases, while inflammatory infiltration was diagnosed in remaining 8 (21%) patients. There was full concordance between radiological report and intraoperative report In 33 cases (87%). The most commonly involved cervical space was masticator space - 31 patients (82%), followed by submandibular space - 27 patients (71%). Dental examination was impossible in 29 patient because of trismus. During analysis of CT studies we evaluated maxillary and mandibular alveolar processes for presence of osteolytic bone lesions around causative teeth roots and we found them in 30 cases (79%). In 32 cases (84%) cervicofacial infection were of mandibular odontogenic origin. CONCLUSIONS: In most cases CT study in patients suspected of odontogenic craniofacial infection revealed presence of an abscess, needing urgent surgery. Inflammatory infiltration of dental origin most frequently involves masticator space, followed by submandibular space. In most cases CT scanning allows for identification of causative teeth, especially when trismus makes detailed clinical examination impossible.