Kou-Mou Huang

Cerebral diffusion tensor images in children with tuberous sclerosis: a preliminary report.

BackgroundIn tuberous sclerosis (TS), tubers usually involve the white matter. Diffusion tensor (DT) images are used to demonstrate white-matter tracts.ObjectiveTo determine the changes in DT indices in supratentorial tubers and associated changes in the white-matter tracts adjacent to tubers in patients with TS.Materials and methodsThe DT imaging indices, including first, second and third eigenvalues (EVs), apparent diffusion coefficients (ADCs), and fractional anisotropy (FA) in the white-matter lesions of tubers, were assessed in seven patients with TS exhibiting developmental delay and compared with controls.ResultsEV1, EV2, EV3, ADC and FA of the white-matter lesions of tubers were significantly different from contralateral unremarkable regions of the brain and from controls (P<0.05). The number of frontal and parietal tubers was significantly negatively correlated with EV1 of the superior longitudinal fasciculi of TS patients (r=−0.60, P =0.04). In addition, TS patients had significantly larger ADCs in the corona radiata and sagittal stratum than the control subjects. EV3s of the inferior longitudinal fasciculus and sagittal stratum were significantly more increased in the TS patients than in the control subjects.ConclusionsEV1, EV2, EV3, ADC and FA maps are potential tools for demonstrating cerebral white-matter changes owing to TS.

Diffusion-weighted images in children with meningoencephalitis

PURPOSE The objective of the study was to evaluate the maps of apparent diffusion coefficients (ADCs) and diffusion-weighted (DW) images in demonstrating meningoencephalitic lesions in children. MATERIALS AND METHODS Between May 1998 and May 2000, 18 infants and children (4.5-190 months old) suffering from meningoencephalitis were included in the study. The diagnoses were bacterial meningoencephalitis in 8 and aseptic or viral in 10 patients. All 18 patients had brain MRI examinations. In the axial plane, three pulse sequences were performed on all patients: (1) FSE T2W images; (2) fast FLAIR images; (3) single-shot echoplanar DW images were acquired. Another 18 patients from the control group also received DW image examination. ADCs were computed for all regions on each DW image. RESULTS The absolute values of CNRs of lesions on T2W (7.27+/-5.51), FLAIR (5.56+/-5.03) and DW (13.36+/-16.64) images were significantly greater than those on ADC maps (0.42+/-0.30) in the study group of patients (P<.01). In addition, absolute CNRs on DW images were significantly greater than on T2W and FLAIR images (P<.01). However, lesions on ADC maps in the study group have significantly greater CNRs than in the control group (0.13+/-0.12) (P<.01). CNRs on initial DW images from patients with atrophy or swelling of meningoencephalitic lesions were significantly different from the CNRs of those patients without significant changes in meningoencephalitic lesions (P=.02<.05). CONCLUSION The DW image is a sensitive tool for detecting meningoencephalitic lesions and is better than FSE T2W and fast FLAIR images in CNRs. Diffusion MR techniques provides new ways to possibly predict the outcome of intracranial infectious diseases in children.

Anomalous origin of the posterior inferior cerebellar artery from the pre-cavernous portion of the internal carotid artery — a primitive trigeminal artery variant

The majority of previously reported cases of cerebellar arteries originating from the internal carotid arteries (ICAs) arise from the pre-cavernous segment of ICAs. An extremely rare variation in origin of the posterior inferior cerebellar artery (PICA) was shown incidentally from angiography of a patient with cavernous dural arteriovenous (AV) malformation. The PICA was noted to arise from the pre-cavernous portion of the ipsilateral ICA and was found directly supplied by a primitive trigeminal artery variant. However, there was no simultaneous opacification of the basilar artery (BA), superior cerebellar artery @CA) and posterior cerebral artery (PCA) accompanying the primitive trigeminal artery. A brief embryological evaluation is undertaken in this case report regarding this particular carotid-basilar arterial variation.

Comparison of contrast-enhanced magnetization transfer imaging and contrast-enhanced fat saturation T1-weighted imaging in nasopharyngeal carcinoma

Objective The objective of this study was to evaluate the efficacy of contrast-enhanced magnetization transfer (CEMT) imaging in the study of nasopharyngeal carcinoma (NPC). Methods The contrast-to-noise ratio (CNR) of CEMT images was compared with the CNR of contrast-enhanced fat-saturation (CEFS) T1-weighted images in locoregional tumors and adenopathies of 50 patients with pathologically proven NPC. Results The CEMT images showed higher CNRs than CEFS images of local nasopharyngeal regions. The mean CNRs of the precontrast T1-weighted, CEFS, and CEMT images were 4.9, 15.4, and 21.2, respectively. There was a statistically significant difference (p < 0.01) in the CNRs of CEFS and CEMT images. In considering images of nodal metastasis, the mean values in these three groups were 0.7, 16.8, and 19.7, respectively, with the difference (p < 0.05) between CEFS and CEMT being statistically significant. Conclusions The CEMT image with a larger CNR is superior to the CEFS image in detecting locoregional NPC. CEMT can be useful in imaging patients with possible small tumors and local recurrences.

Application of Fluid-Attenuated Inversion Recovery Pulse Sequence in Children with Tuberous Sclerosis

To evaluate the application of Fluid-Attenuated Inversion Recovery (FLAIR) pulse sequence to increase the sensitivity of detecting tubers in tuberous sclerosis patients compared with fast spin-echo T2-weighted (FSET2W) image, we obtained 12 magnetic resonance (MR) images in 10 patients (mean age = 57.7 months old). Among the 12 examinations, 114 cortical and 128 subcortical tubers were revealed on the FLAIR images, whereas 54 and 72 tubers were found respectively on the FSET2W images. This may be due to the FLAIR pulse sequences remarkably attenuated CSF signals in comparison with the FSET2W images. However, FSET2W image delineated more subependymal nodules than FLAIR imaging did. Gd-DTPA enhanced T1W image is the most suitable pulse sequence to detect giant cell astrocytoma near the foramen of Monro. The results in cases of infants and little children were similar.

Internal Derangement of the Temporomandibular Joint: Correlation between MRI and Clinical Findings

In patients suffering from internal derangement of temporomandibular joint (TMJ), both sideways and rotational displacement of the TMJ menisci are common, and most cases have bilateral involvement. The purpose of this study was to evaluate the value of bilateral cornal images of TMJs in patients suspected of internal derangement. Seventy-nine TMJs in totally 40 patients were studied using magnetic resonance imaging techniques including: 1) oblique sagittal, T1-weighted spin echo images in the closed-and opened-mouth positions in 79 TMJs; 2) oblique sagittal, multiplanar gradient recalled images in the closed-mouth projection in 43 TMJs; 3) oblique coronal, spin echo, T1-weighted images in the closed-mouth position in 65 TMJs. Bilateral coronal and sagittal images in the closed-and opened-mouth positions were obtained in 25 patients. With the additional use of oblique coronal images, the diagnosis changed from normal to abnormal in one joint and from anterior displacement to rotational displacement in TMJs. Bilateral TMJs were involved with internal derangement in 16 of 25 patients. Joint clicking was significantly more common in patients with less mobile menisci overlying mandibular condyles with normal or increased mobility. Our results indicated routine use of oblique coronal images is valuable in the detection of rotational and sidweways displacement. Use of a dual TMJ surface coil is suitable for detection of bilaterally displaced menisci.(Tzu Chi Med J1998;10:29-36)

MR Images of Moyamoya Disease: Report of a Case

Moyamoya disease is a rare disease entity, but it should be taken into consideration in young stroke patients. We report a five-year-old girl with repetitive hemiparesis who underwent CT, MRI and angiographic examinations. The characteristic features of moyamoya disease are progressive narrowing of the supraclinoid portion of the internal carotid artery and its main branches, followed by many collaterals. MR images without contrast medium enhancement can demonstrate these abnormal vessels well. They are diminished arteries of the circle of Willis and the development of parenchymal collaterals. MR also provides better tissue contrast to depict the parenchymal manifestations than that of CT study. Angiography is an invasive but diagnostic procedure. MRI study may be an alternative imaging modality to evaluate the cases with clinical suspicion of moyamoya disease, non-invasively. (Tzu Chi Med J 1994; 6: 281-285)