Transition into driven equilibrium of the balanced steady-state free precession as an ultrafast multisection T2-weighted imaging of the brain.

BACKGROUND AND PURPOSE: Current T2-weighted imaging takes >3 minutes to perform, for which the ultrafast transition into driven equilibrium (TIDE) technique may be potentially helpful. This study qualitatively and quantitatively evaluates the imaging of transition into driven equilibrium of the balanced steady-state free precession (TIDE) compared with TSE and turbo gradient spin-echo on T2-weighted MR images. MATERIALS AND METHODS: Thirty healthy volunteers were examined with T2-weighted images by using TIDE, TSE, and turbo gradient spin-echo sequences. Imaging was evaluated qualitatively by 2 independent observers on the basis of a 4-point rating scale regarding contrast characteristics and artifacts behavior. Image SNR and contrast-to-noise ratio were quantitatively assessed. RESULTS: TIDE provided T2-weighted contrast similar to that in TSE and turbo gradient spin-echo with only one-eighth of the scan time. TIDE showed gray-white matter differentiation and iron-load sensitivity inferior that of TSE and turbo gradient spin-echo, but with improved motion artifacts reduction on qualitative scores. Nonmotion ghosting artifacts were uniquely found in TIDE images. The overall SNRs of TSE were 1.9-2.0 times those of turbo gradient spin-echo and 1.7-2.2 times of those of TIDE for brain tissue (P < .0001). TIDE had a higher contrast-to-noise ratio than TSE (P = .169) and turbo gradient spin-echo (P < .0001) regarding non-iron-containing gray matter versus white matter. TIDE had a lower contrast-to-noise ratio than turbo gradient spin-echo and TSE (P < .0001) between iron-containing gray matter and white matter. CONCLUSIONS: TIDE provides T2-weighted images with reduced scan times and reduced motion artifacts compared with TSE and turbo gradient spin-echo with the trade-off of reduced SNR and poorer gray-white matter differentiation.

Occurrence and distribution of Naegleria species from thermal spring environments in Taiwan.

UNLABELLED: Naegleria spp. is a free-living amoeba that can be found in the natural environment. A number of Naegleria spp. can cause fatal infections in the central nervous system in humans and animals, and the most important source of infection is through direct water contact. In this study, water samples from various thermal springs were taken from four thermal spring areas. Naegleria spp. was detected via culture confirmation and molecular taxonomic identification. Among the 60 samples obtained, Naegleria spp. was identified in 26 (43·3%) samples. The identified species included Naegleria australiensis, Naegleria gruberi, Naegleria lovaniensis and Naegleria mexicana. The presence of living Naegleria spp. was significantly associated with elevated pH value in the water sample. SIGNIFICANCE AND IMPACT OF STUDY: In this study, we examined the presence of living Naegleria spp. in thermal spring waters in south-eastern Taiwan. Naegleria spp. was isolated and culture-confirmed from thermal spring water. Naegleria fowleri was not found in all water samples, and Naegleria australiensis was the most common Naegleria genotype.

CT Angiographic Diagnosis of a Ruptured Intraventricular Arteriovenous Malformation in a Teenager Playing a Video Game.

Intraventricular arteriovenous malformation (AVM) is a rare congenital vascular disorder that is often associated with primary intraventricular hemorrhage (IVH) and a rapid clinical course. Acute imaging diagnosis requires depiction of both the location of hemorrhage and vascular nidus for emergent management. In this report, a 17-year-old teenager developed primary IVH with presentation of consciousness change during a video game. Multidetector-row computed tomographic angiography (CTA) demonstrated an AVM in the right lateral ventricle and its angioarchitectural relationship to the surrounding intracranial structures. Although selective angiography is essential both in planning treatment for cerebral AVMs and in establishing the final diagnosis, CTA can be an important first-line imaging modality to quickly confirm the diagnosis and hence initiate prompt management.

Prediction of conversion from clinically isolated syndrome to clinically definite multiple sclerosis according to baseline MRI findings: comparison of revised McDonald criteria and Swanton modified criteria.

BACKGROUND: The International Panel on the Diagnosis of Multiple Sclerosis first incorporated abnormalities demonstrated by brain and spinal cord MRI into the diagnostic criteria (McDonald criteria) for multiple sclerosis (MS), which were later revised in 2005. In 2006, Swanton and colleagues modified the MRI criteria to simplify and speed the diagnosis. OBJECTIVE: The purpose of this study was to compare the ability of two sets of criteria (the revised McDonald MRI criteria and Swanton's modified criteria) to predict conversion from clinically isolated syndrome (CIS) to clinically definite multiple sclerosis (CDMS) from baseline MRI findings. METHODS: Sixty-four patients presenting with CIS suggestive of multiple sclerosis were recruited from 2001 to 2006 and followed up for at least 2 years. Their baseline brain and spinal cord MRI studies were retrospectively evaluated. The patients who developed CDMS during follow-up were treated as positive cases. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of the two MRI dissemination-in-space criteria were calculated. RESULTS: Thirty patients (46.9%) converted to CDMS. The sensitivity specificity, PPV, NPV and accuracy (%) of the revised McDonald criteria were 53, 100, 100, 71 and 78, respectively, while those for Swanton's modified criteria were 60, 100, 100, 74 and 81. CONCLUSIONS: In conclusion, Swanton's modified criteria are more sensitive and accurate (but not significantly so). However, Swanton's criteria are simpler to use and have equally high specificity and PPV.

Endovascular procedures for cerebrovenous disorders.

Cerebral venous anomalies may have a variety of clinical consequences. MR or CT venogram can assist the imaging diagnosis; yet, cerebral angiogram may be required to confirm or establish the correct diagnosis. Venous anomalies predisposing venous hypertension may be categorized into three major entities such as congenital variations, outflow obstruction, and increased blood flow. The degree of clinical presentations of venous hypertension depends upon the chronicity or acuteness. Venous hypertension may lead to venous congestion with edema, hemorrhage and encephalopathy. Endovascular therapeutic procedures may be employed to relieve venous congestion either from reducing blood flow or relieving obstruction. Those endovascular treatment options include embolization, thrombolysis and angioplastic stentings.

Diffusion-tensor MR imaging for evaluation of the efficacy of hyperbaric oxygen therapy in patients with delayed neuropsychiatric syndrome caused by carbon monoxide inhalation.

The purpose of this study is to assess the efficacy of hyperbaric oxygen therapy (HBOT) in patients with delayed neuropsychiatric syndrome (DNS) caused by carbon monoxide (CO) inhalation using diffusion tensor magnetic resonance (MR) imaging and neuropsychological test. Conventional and diffusion tensor brain MR imaging exams were performed in six patients with DNS immediately before and 3 months after the HBOT to obtain fractional anisotropy (FA) values. Six age- and sex-matched normal control subjects also received MR exams for comparison. Mini-Mental State Examination (MMSE) was also performed in patients immediately before and 3 months after the HBOT. A significantly higher mean FA value was found in control subjects as compared with the patients both before and 3 months after the HBOT (P < 0.001). The mean FA value 3 months after the HBOT was also significantly higher than that before the HBOT in the patient group (P < 0.001). All of the patients regained full scores in the MMSE 3 months after the HBOT. Diffusion tensor MR imaging can be a quantitative method for the assessment of the white matter change and monitor the treatment response in patients of CO-induced DNS with a good clinical correlation. HBO may be an effective therapy for DNS.

Ganglion cysts of the cruciate ligaments.

PURPOSE: To evaluate the MR findings of ganglion cysts of the cruciate ligaments in correlation with clinical findings. MATERIAL AND METHODS: We reviewed 12 patients with ganglion cysts of the cruciate ligaments obtained from a medical record of 4153 consecutive patients referred for knee MR examinations. All patients presented with chronic knee pain and 4 had restriction of knee motion. The MR imaging findings of the cysts were evaluated and correlated with clinical manifestations. RESULTS: Seven ganglion cysts were found in the posterior cruciate ligaments and 5 in the anterior cruciate ligaments. All cysts were lobulated (n=7) or fusiform (n=5) in shape, 1.8-4.5 cm in size, along the posterior surface in the proximal or distal end of the ligaments. Ten patients had arthroscopic resection or aspiration of their cysts, became symptom free and had no recurrence on follow-up MR examinations. Two cysts reduced in size spontaneously by conservative treatment. CONCLUSION: MR imaging can offer useful information in detection and diagnosis of patients with chronic knee pain due to ganglion cysts of the cruciate ligaments. The size and location of the ganglion cysts can attribute to the clinical manifestations.

Synovial chondroma of the ankle in a young child after recent trauma: CT and MR features.

We report a case of synovial chondroma of the left ankle in an 11-year-old boy presenting with soft tissue swelling after recent trauma. The noncalcified or nonossified intraarticular chondroma arising from metaplastic synovium has characteristic imaging appearance on computed tomography (CT) and magnetic resonance imaging (MRI). A lobulated mass of fluid-like density and signal intensity along with internal septa are characteristic features on CT and MRI. The knowledge of CT and MRI features of noncalcified or nonossified synovial chondroma is important to distinguish from the simple or complicated effusion, hemarthrosis, or other synovial process.

Imaging findings of intradiaphragmatic bronchogenic cyst: a case report.

Isolated intradiaphragmatic bronchogenic cysts are extremely rare. Here, we report a case of intradiaphragmatic bronchogenic cyst with calcifications in a 34-year-old man presenting with no clinical symptoms. Imaging studies of the chest, including chest roentgenogram and computerized tomography (CT), revealed a left posterior mediastinal mass that abutted onto the left diaphragmatic crus with multiple calcifications and showed no enhancement after contrast administration on CT. The patient underwent surgical resection of the mass. Intradiaphragmatic bronchogenic cyst with calcifications was diagnosed by pathology. The patient was discharged 10 days after the operation, and no complication was found 3 months later at follow-up.

Primary hemangiopericytoma of the tibia: MR and angiographic correlation.

The Magnetic Resonance Imaging (MRI) appearances of primary osseous hemangiopericytoma (HPC) have been rarely described. We report on a 46-year-old Chinese man with primary osseous HPC of the right tibia. The characteristic vascular distribution of this tumor, presenting with a "spoke-wheel" appearance on MR images and with angiographic correlation, is described. Although not pathognomonic, this MR appearance may be an important finding in suggesting the diagnosis of osseous HPC.