Auditory Pathway Features Determined by DTI in Subjects with Unilateral Acoustic Neuroma.

PURPOSE: In the studies concerning the pathology of the auditory pathway in the vestibulocochlear system, few use advanced neuroimaging applications of magnetic resonance imaging (MRI) such as diffusion tensor imaging (DTI). Those who did use reported DTI changes only at the lateral lemniscus and inferior colliculus level. The aim of our study was to determine diffusion changes in the bilateral auditory pathways of subjects with unilateral acoustic neuroma (AN) and compare them with healthy controls. MATERIAL AND METHODS: A total of 15 subjects with unilateral AN along with 11 controls underwent routine MRI and DTI. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values obtained from the lateral lemniscus, inferior colliculus, corpus geniculatum mediale, and Heschl's gyrus of the auditory pathway were then compared. RESULTS: The subjects' ADC values measured from the contralateral side were significantly higher at the lateral lemniscus, inferior colliculus, and corpus geniculatum mediale compared with those of the controls. Also, decreased FA values were noted at the inferior colliculus for both the contralateral and ipsilateral sides. The highest ADC values were detected in the inferior colliculus of the auditory pathway. CONCLUSIONS: In the auditory pathway of subjects with AN, the contralateral side is more affected than the ipsilateral side, the most affected region being the inferior colliculus. DTI is an advanced neuroimaging technique that can be used to determine the presence of microstructural damage to the auditory pathway in subjects with AN, whereas conventional MRI is not sensitive enough to detect damage.

Graves' ophthalmopathy: the role of diffusion-weighted imaging in detecting involvement of extraocular muscles in early period of disease.

OBJECTIVE: To evaluate involvement of the extraocular muscle (EOM) using diffusion-weighted imaging (DWI), to determine whether there is correlation with conventional orbital MRI and apparent diffusion coefficient (ADC) values in patients with Graves' ophthalmopathy (GO). METHODS: 35 patients known clinically with GO and 21 healthy controls were studied. Patients were assessed with clinical activity scores. All subjects underwent conventional MRI and DWI study. Involvement of the EOM was evaluated. The patients were classified as involved or uninvolved on orbital MRI and their ADC values in DWI compared. RESULTS: There was significant difference in the mean ADC value of all the EOMs in patients vs controls. The ADC values of all the EOMs were higher in patients. There were significant differences in ADC values between uninvolved muscles on conventional MRI and controls for the MR, SR and LR. There was no significant difference in ADC value between the two groups when considering the IR. ADC values of medial, lateral and superior rectus muscles were increased. CONCLUSION: Increased ADC values of the EOM in patients with GO suggest that EOM damage begins at a very early stage before being detected on routine orbital MRI. The routine MRI with DWI sequence will be a useful adjunct in the selection of a group of patients most likely to benefit from early treatment. ADVANCES IN KNOWLEDGE: This study can help to evaluate the involvement of GO in early period with MRI added DWI.

Cavernous Sinus: A Comprehensive Review of its Anatomy, Pathologic Conditions, and Imaging Features.

The purpose of this article was to review the anatomy of the cavernous sinus (CS), illustrate numerous lesions that can affect the CS, and emphasize the imaging characteristics for each lesion to further refine the differential diagnoses. The CS, notwithstanding its small size, contains a complicated and crucial network that consists of the carotid artery, the venous plexus, and cranial nerves. The wide-ranging types of pathologies that can involve the CS can be roughly classified as tumoral, congenital, infectious/inflammatory/granulomatous, and vascular. Conditions that affect the CS usually lead to symptoms that are similar to each other; thus, for diagnosis, imaging procedures are required. Radiological evaluations are also required to detect pre- and postoperative CS invasion. Magnetic resonance imaging, which can be supplemented with thin-section contrast-enhanced sequences, is the preferred imaging technique for evaluating the CS. For correct diagnosis of CS lesions and accurate evaluations of CS invasions, it is essential to carefully analyze the anatomical structures within the CS and to acquire precise knowledge about the imaging features of CS lesions, which may frequently overlap.

Microstructural brain changes in acromegaly: quantitative analysis by diffusion tensor imaging.

OBJECTIVE: We examined brain diffusion changes of patients with acromegaly. We searched whether there are differences in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values between remission and non-remission patients with acromegaly and investigated any effect of time of hormone exposure on diffusion metrics. METHODS: The values of FA and ADC were calculated in a total of 35 patients with acromegaly and 28 control subjects. Patients were subdivided into remission and non-remission groups. We looked at brain FA and ADC differences among the groups and looked for any relation between the diffusion changes and time of hormone exposure among the patients with acromegaly. RESULTS: We found decreased FA and increased ADC values in some of the growth hormone responsive areas. There were no significant brain diffusion changes between remission and non-remission groups. The most affected areas were the hypothalamus, parietal white matter and pre-motor cortex in patients with acromegaly. In terms of hormone exposure time among the patients with acromegaly, there was no effect of disease duration on brain microstructural changes. CONCLUSION: All patients with acromegaly showed increased brain diffusion with no relation to disease duration and treatment status. We suggested that in patients with acromegaly, brain damage had already occurred in the subclinical period before symptom onset. ADVANCES IN KNOWLEDGE: This study contributes to the understanding of the mechanisms in acromegaly.

MR imaging findings in brachial plexopathy with thoracic outlet syndrome.

The BPL is a part of the peripheral nervous system. Many disease processes affect the BPL. In this article, on the basis of 60 patients, we reviewed MR imaging findings of subjects with brachial plexopathy. Different varieties of BPL lesions are discussed.

Regional differences in diffusion tensor imaging measurements: assessment of intrarater and interrater variability.

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) has become a valuable tool in both the research and clinical evaluation of subjects. We sought to quantify interobserver and intraobserver variability of diffusivity and diffusion anisotropy measurements with regard to specific regions of interest (ROIs). MATERIALS AND METHODS: The subject group consisted of 5 healthy control subjects and 7 study subjects (all males; 16-19 years old; mean age = 17.5 years), as part of a protocol for closed head injury. Two whole-brain DTI scans were acquired on a 3T scanner for each subject. Analysis was performed using a ROI approach. Two independent observers analyzed the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) indices in the corpus callosum, cortical spinal tract, internal capsules (ICs), basal ganglia, and centrum semiovale (CSO). Intraobserver and interobserver variability were calculated for the mean ADC, FA, and ordered eigenvalues of the diffusion tensor (lambda(1), lambda(2), and lambda(3)). RESULTS: The overall kappa statistic for intraobserver variability for both observers showed slight-to-substantial agreement (kappa = 0.02-0.69), however FA values in the CSO showed only slight agreement. Interobserver agreement was also slight to substantial for these DTI measurements with high variability in FA values in the IC and CSO. CONCLUSIONS: When one is comparing 2 DTI measurements, it is important to assess intraobserver and interobserver variability. We recommend caution in the analysis of DTI contrasts in the IC and CSO, because we have found the widest range of variability in measurements within these structures.

Giant cell reparative granuloma of the sphenoid bone.

We present 2 patients with giant cell reparative granuloma (GCRG) of the sphenoid bone. The first patient is an 8-year-old boy with involvement of the greater wing, and the second is a 53- year-old man with a lateral pterygoid plate mass. Both patients presented with rapid expansion of lytic bone lesions, which had solid and cystic components and lacked matrix calcification. Biopsies were indeterminate for definitive diagnoses. The radiologic appearance, location, and incidence of the lesions, and the patient's age and medical history are helpful aids in narrowing the differential diagnosis of sphenoid bone lesions. However, the imaging and, occasionally, even the histologic findings may not suggest the specific diagnosis of GCRG, which must be added into the differential diagnosis of rapidly enlarging cystic bone lesions of the sphenoid bone.

US and CT findings of multicentric leiomyosarcomatosis.

This article presents a case of leiomyosarcomatosis with widespread lesions involving the soft tissues and the most unlikely organs such as thyroid and salivary glands, pancreas, ligamentum teres, bladder wall, and bones without lymph node or distant metastasis. The CT and US findings of this rare phenomenon are discussed with regard to the literature.