OBJECTIVE: The purpose of this study was to determine the diagnostic utility of low-dose CT with knowledge-based iterative model reconstruction (IMR) for the evaluation of parotid gland tumors. MATERIALS AND METHODS: This prospective study included 42 consecutive patients who had undergone low-dose contrast-enhanced CT for the evaluation of suspected parotid gland tumors. Prior or subsequent non-low-dose CT scans within 12 months were available in 10 of the participants. Background noise (BN), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were compared between non-low-dose CT images and images generated using filtered back projection (FBP), hybrid iterative reconstruction (iDose⁴; Philips Healthcare), and knowledge-based IMR. Subjective image quality was rated by two radiologists using five-point grading scales to assess the overall image quality, delineation of lesion contour, image sharpness, and noise. RESULTS: With the IMR algorithm, background noise (IMR, 4.24 ± 3.77; iDose⁴, 8.77 ± 3.85; FBP, 11.73 ± 4.06; p = 0.037 [IMR vs. iDose⁴] and p < 0.001 [IMR vs. FBP]) was significantly lower and SNR (IMR, 23.93 ± 7.49; iDose⁴, 10.20 ± 3.29; FBP, 7.33 ± 2.03; p = 0.011 [IMR vs. iDose⁴] and p < 0.001 [IMR vs. FBP]) was significantly higher compared with the other two algorithms. The CNR was also significantly higher with the IMR compared with the FBP (25.76 ± 11.88 vs. 9.02 ± 3.18, p < 0.001). There was no significant difference in BN, SNR, and CNR between low-dose CT with the IMR algorithm and non-low-dose CT. Subjective image analysis revealed that IMR-generated low-dose CT images showed significantly better overall image quality and delineation of lesion contour with lesser noise, compared with those generated using FBP by both reviewers 1 and 2 (4 vs. 3; 4 vs. 3; and 3–4 vs. 2; p < 0.05 for all pairs), although there was no significant difference in subjective image quality scores between IMR-generated low-dose CT and non-low-dose CT images. CONCLUSION: Iterative model reconstruction-generated low-dose CT is an alternative to standard non-low-dose CT without significantly affecting image quality for the evaluation of parotid gland tumors.
Feasibility Studies* ; Humans ; Image Processing, Computer-Assisted ; Noise ; Parotid Gland* ; Prospective Studies ; Radiation Dosage ; Signal-To-Noise Ratio ; Tomography, X-Ray Computed* ; Weights and Measures

Congenital lymphedema is a rare disorder of unknown etiology which affects the extremities, preponderantly the lower extremities, at or immediately after birth. We experienced a case of congenital lymphedema in a newborn with generalized edema on the left lower extremity. We performed lymphangioscintigraphy and MRI for diagnosis. Microlymphaticovenous anastomosis was done on 16 days after birth and the patient showed clinical improvement. We report this case with brief review of the related literature.
Diagnosis ; Edema ; Extremities ; Humans ; Infant, Newborn ; Lower Extremity ; Lymphedema* ; Magnetic Resonance Imaging ; Parturition

PURPOSE: Diffusion tensor imaging provides better understanding of pathophysiology of congenital anomalies, involving central nervous system. This study was aimed to specify the pathogenetic mechanism of heterotopia, proved by diffusion tensor imaging, and establish new findings of heterotopia on fractional anisotropy maps. MATERIALS AND METHODS: Diffusion-weighted imaging data from 11 patients (M : F = 7 : 4, aged from 1 to 22 years, mean = 12.3 years) who visited the epilepsy clinic and received a routine seizure protocol MRI exam were retrospectively analyzed. Fractional anisotropy (FA) maps were generated from diffusion tensor imaging of 11 patients with heterotopia. Regions of interests (ROI) were placed in cerebral cortex, heterotopic gray matter and deep gray matter, including putamen. ANOVA analysis was performed for comparison of different gray matter tissues. RESULTS: Heterotopic gray matter showed signal intensities similar to normal gray matter on T1 and T2 weighted MRI. The measured FA of heterotopic gray matter was higher than that of cortical gray matter (0.236 +/- 0.011 vs. 0.169 +/- 0.015, p < 0.01, one way ANOVA), and slightly lower than that of deep gray matter (0.236 +/- 0.011 vs. 0.259 +/- 0.016, p < 0.01). CONCLUSION: Increased FA of heterotopic gray matter suggests arrested neuron during radial migration and provides better understanding of neurodevelopment.

PURPOSE: Mycophenolic acid (MPA), a selective inhibitor of inosine monophosphate dehydrogenase (IMPDH), is the active metabolite of the immunosuppressive drug, mycophenolate mofetil (MMF). MMF is used to prevent an immune- mediate rejection response following organ transplantation via the inhibition of the IMPDH and GTP biosynthesis pathway. This study was designed to elucidate the mechanism by which MPA exerts its cytotoxic effect on human T lymphocytic and monocytic cell lines. METHODS: MOLT-4 and U937 cell lines were treated with MPA. Cell viability, expression of Bcl2 family proteins and Fas/Fas-L, effects of antioxidants and intracellular Ca2+ regulating agents and apoptosis were measured using a variety of microscopic and biochemical techniques. RESULTS: MPA induced the death of U937 and MOLT-4 cells in dose and time dependent manners, which was revealed an apoptosis with a characteristic ladder pattern of DNA fragmentation. In addition, BAPTA/AM, an intracellular Ca2+ chelator protected MOLT-4 cells from MPA treated apoptosis, although it did not have an additive with thapsigargin, and increases cytosolic Ca2+ stores. However, antioxidants including reduced glutathione (GSH) and N-acetyl-L-cysteine (NAC) did not inhibit the apoptosis of cells by MPA. Furthermore, guanosine suppressed MPA induced apoptosis of MOLT-4 lymphocytes, although adenosine did not. MPA also increased the catalytic activity of caspase family cysteine proteases including caspase-8, 9 and 3 proteases in MOLT-4 cells. Sequential activation indicated that the cleavage of caspase-8 and 9 precedes those of caspase-3. CONCLUSION: The results suggest that MPA induces the apoptotic death of MOLT-4 lymphocytes via the activations of caspase family proteases and the depletion of GTP.
Acetylcysteine ; Adenosine ; Antioxidants ; Apoptosis ; Caspase 3 ; Caspase 8 ; Cell Line ; Cell Survival ; Cysteine Proteases ; Cytosol ; DNA Fragmentation ; Glutathione ; Guanosine ; Guanosine Triphosphate ; Humans ; Inosine Monophosphate ; Lymphocytes ; Mycophenolic Acid* ; Organ Transplantation ; Oxidoreductases ; Peptide Hydrolases ; Signal Transduction* ; T-Lymphocytes* ; Thapsigargin ; Transplants ; U937 Cells

PURPOSE: To achieve maximal safe resection during brain tumor surgery, functional image-merged neuronavigation is widely used. We retrospectively reviewed our cases in which diffusion tensor image (DTI)-merged functional neuronavigation was performed during surgery. MATERIALS AND METHODS: Between November 2008 and May 2010, 123 patients underwent surgery utilizing DTI-merged neuronavigation. Anatomical magnetic resonance images (MRI) were obtained preoperatively and fused with DTI of major white matter tracts, such as the corticospinal tract, optic radiation, or arcuate fasciculus. We used this fused image for functional neuronavigation during brain tumor surgery of eloquent areas. We checked the DTI images together with postoperative MRI images and evaluated the integrity of white matter tracts. RESULTS: A single white matter tract was inspected in 78 patients, and two or more white matter tracts were checked in 45 patients. Among the 123 patients, a grossly total resection was achieved in 90 patients (73.2%), subtotal resection in 29 patients (23.6%), and partial resection in 4 patients (3.3%). Postoperative neurologic outcomes, compared with preoperative function, included the following: 100 patients (81.3%) displayed improvement of neurologic symptoms or no change, 7 patients (5.7%) experienced postoperative permanent neurologic deterioration (additional or aggravated neurologic symptoms), and 16 patients (13.0%) demonstrated transient worsening. CONCLUSION: DTI-merged functional neuronavigation could be a useful tool in brain tumor surgery for maximal safe resection. However, there are still limitations, including white matter tract shift, during surgery and in DTI itself. Further studies should be conducted to overcome these limitations.
Adolescent ; Adult ; Aged ; Brain Neoplasms/pathology/*surgery ; *Diffusion Tensor Imaging ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; *Neuronavigation ; Neurosurgical Procedures/*methods ; Postoperative Period ; Preoperative Period ; Retrospective Studies

OBJECTIVE: The precise intra- vs. extradural localization of aneurysms involving the paraclinoid internal carotid artery is critical for the evaluation of patients being considered for aneurysm surgery. The purpose of this study was to investigate the clinical usefulness of T2-weighted three-dimensional (3-D) fast spin-echo (FSE) magnetic resonance (MR) imaging in the evaluation of unruptured paraclinoid aneurysms. METHODS: Twenty-eight patients with unruptured cerebral aneurysms in their paraclinoid regions were prospectively evaluated using a T2-weighted 3-D FSE MR imaging technique with oblique coronal sections. The MR images were assessed for the location of the cerebral aneurysm in relation to the dural ring and other surrounding anatomic compartments, and were also compared with the surgical or angiographic findings. RESULTS: All 28 aneurysms were identified by T2-weighted 3D FSE MR imaging, which showed the precise anatomic relationships in regards to the subarachnoid space and the surrounding anatomic structures. Consequently, 13 aneurysms were determined to be intradural and the other 15 were deemed extradural as they were confined to the cavernous sinus. Of the 13 aneurysms with intradural locations, three superior hypophyseal artery aneurysms were found to be situated intradurally upon operation. CONCLUSION: High-resolution T2-weighted 3-D FSE MR imaging is capable of confirming whether a cerebral aneurysm at the paraclinoid region is intradural or extradural, because of the MR imaging's high spatial resolution. The images may help in identifying patients with intradural aneurysms who require treatment, and they also can provide valuable information in the treatment plan for paraclinoid aneurysms.
Aneurysm ; Arteries ; Carotid Artery, Internal ; Cavernous Sinus ; Humans ; Intracranial Aneurysm ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy ; Magnetics ; Magnets ; Prospective Studies ; Subarachnoid Space

The pharyngoesophageal diverticulum in the lower part of the neck can be detected using neck ultrasonography. We present a case of pharyngoesophageal diverticulum mimicking a thyroid nodule, which was found incidentally by ultrasonography, and discuss its peculiar findings, which might be useful to diagnose pharyngoesophageal diverticulum and to prevent invasive procedures such as needle aspiration biopsy.
Aged ; Barium/diagnostic use ; Case Report ; Diagnosis, Differential ; Esophagus/radiography ; Human ; Male ; Thyroid Nodule/diagnosis/ultrasonography ; Zenker Diverticulum/diagnosis/*ultrasonography

We report two cases of paratracheal air cyst discovered incidentally at neck ultrasonography and confirmed at CT. The cysts were located at the inferoposterior aspect of the right lobe of the thyroid. Ultrasonography revealed an ill-defined hypoechoic mass containing hyperechoic foci which mimicked calcifications. Neck CT confirmed the presence of an ill-defined air pocket which communicated with the trachea through a slit.

OBJECTIVE: Many diffusion tensor imaging (DTI) studies of the corpus callosum (CC) have been performed with a relatively thick slice thickness in the axial plane, which may result in underestimating the fractional anisotropy (FA) of the CC due to a partial volume effect. We hypothesized that the FA of the CC can be more accurately measured by using mid-sagittal DTI. We compared the FA values of the CC between the axial and mid-sagittal DTI. MATERIALS AND METHODS: Fourteen healthy volunteers underwent MRI at 3.0 T. DTI was performed in both the mid-sagittal and axial planes. One 5-mm mid-sagittal image and twenty-five 2-mm axial images were obtained for the CC. The five regions of interest (ROIs) that included the prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and parietal, temporal and occipital regions (V) were drawn along the border of the CC on each sagittal FA map. The FA values obtained from each region were compared between the two sagittal maps. RESULTS: The FA values of all the regions, except for region V, were significantly increased on the mid-sagittal imaging. The FA values in region IV were significantly underestimated on the mid-sagittal image from the axial imaging, compared with those in the regions I and V (p = 0.037 and p = 0.001, respectively). CONCLUSION: The FA values of the CC were significantly higher on the mid-sagittal DTI than those on the axial DTI in regions I-IV, and particularly in the region IV. Mid-sagittal DTI may provide more accurate FA values of the CC than can the axial DTI, and mid-sagittal DTI may be more desirable for studies that compare between patients and healthy subjects.
Adult ; Analysis of Variance ; Anisotropy ; Brain Mapping/*methods ; Corpus Callosum/*anatomy & histology ; Diffusion Magnetic Resonance Imaging/*methods ; Female ; Humans ; Image Processing, Computer-Assisted ; Male ; Statistics, Nonparametric

Various manifestations of brain involvement for patients with virus-associated hemophagocytic syndrome have been reported. Here, we report on the sequential magnetic resonance (MR) findings of acute demyelination of the entire brain with subsequent brain atrophy in a follow-up study of a 25-month- old boy who was admitted with fever and then diagnosed with infectious mononucleosis and EBV-associated hemophagocytic syndrome. We also review other conditions that should be included in the differential diagnosis of this disease.
Male ; *Magnetic Resonance Imaging ; Lymphohistiocytosis, Hemophagocytic/etiology/*pathology/virology ; Humans ; Epstein-Barr Virus Infections/complications/*pathology ; Diagnosis, Differential ; Demyelinating Diseases/complications/*pathology/virology ; Child, Preschool ; Brain Diseases/complications/*pathology/virology