Fat-Water Swaps in Iterative Decomposition of Water and Fat With Echo Asymmetry and Least-Squares Estimation Magnetic Resonance Imaging for Postinstrumentation Spine.

OBJECTIVE: To determine the frequencies of fat-water swaps in iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) water-only images of the postinstrumentation spine and discuss the efficiency of in-phase imaging in improving visibility of the thecal sac. MATERIALS AND METHODS: A total of 276 patients (167 women; mean age, 62.3 years; range, 23-89 years) with metallic devices on the lumbar spine who received complete routine 1.5 T MR imaging, including axial and sagittal images of T1-weighted, T2-weighted, and T2-weighted IDEAL sequences, were included. The exclusion criteria were significant motion artifacts and severe metallic artifacts in any one of the sequences. The images were reviewed by two radiologists to identify fat-water swaps that were divided into 3 groups: extraspinal swaps, intraspinal swaps in sagittal images, and intraspinal swaps in axial images. The qualitative evaluations for the spinal canal in axial images were performed by rating on a five-point scale. Side-by-side comparisons of T2-weighted images and IDEAL in-phase images were also performed. RESULTS: In patient-based data of 276 patients, extraspinal fat-water swaps were noted in 10 patients (3.6%) and intraspinal swaps were noted in 160 patients (58.0%). The intraspinal swaps had a higher incidence in the patients with more levels of metallic devices with screws and the trend was not noted in the extraspinal swaps. A total of 928 axial levels were evaluated in the level-based data of axial images. T1-weighted, T2-weighted, and IDEAL in-phase images had significantly better imaging quality than the IDEAL water-only images (3.9 ± 0.4, 3.9 ± 0.3, 3.8 ± 0.4 vs 3.0 ± 1.3, all P < 0.001). Compared with T2-weighted images, most of the IDEAL in-phase images (reader 1, 90.9%; reader 2, 86.7%) present similar quality. CONCLUSION: Iterative decomposition of water and fat with echo asymmetry and least-squares estimation sequence can provide good fat suppression in most spine MRI with metallic devices but the loss of cerebrospinal fluid signal intensities due to fat-water swaps are noted in more than half of postinstrumentation spine. Routine reconstruction of in-phase images is recommended to improve evaluation of the thecal sac by avoiding pitfall caused by fat-water swaps.

Convex border of peripheral non-small cell lung cancer on CT images as a potential indicator of pleural invasion.

The aim of the study is to evaluate the use of the tumor border in peripheral non-small cell lung cancer (NSCLC) as an indicator of pleural invasion.This retrospective study was performed at a single tertiary center. The analysis of 136 patients with peripheral NSCLC included 101 (74.3%) patients with pathologically proven pleural invasion and 35 (25.7%) patients without pleural invasion. The tumor borders on conventional computed tomography (CT) were classified into 5 types on lung window setting: type 1, S or reverse S border with a blunt angle; type 2, sharp angle; type 3, concave border with a blunt angle; type 4, straight border with a perpendicular angle; and type 5, convex border with a perpendicular or blunt angle. In patients with more than 1 tumor border type, the priority was type 5, 4, 3, 2, and 1. Blunt angle, pleural contact >3 cm, and adjacent pleural thickening were also recorded for comparison with pleural invasion of peripheral tumors.Tumor border types 2 and 5 significantly differed between patients with and without pleural invasion (P = .001 and P < .001, respectively). Patients with and without pleural invasion did not significantly differ in tumor border type 1, tumor border type 3, tumor border type 4, blunt angle, pleural contact >3 cm, or pleural thickening. Tumor border type 5 was a moderate indicator of pleural invasion with positive LR, 5.20; accuracy, 57%; sensitivity, 45%; specificity, 91%; PPV, 94%; and NPV, 36%. Tumor border type 2 was a weak indicator of pleural invasion with positive LR, 0.51; accuracy, 34%; sensitivity, 34%; specificity, 34%; PPV, 60%; and NPV, 15%.Tumor border type 5 has a high PPV and high specificity for predicting pleural invasion by peripheral NSCLC.

Follow-up for covered stent treatment of carotid blow-out syndrome in patients with head and neck cancer.

OBJECTIVE: Carotid blow-out syndrome (CBS) is a life-threatening complication of head and neck cancer (HNC). One of the various methods used for emergency management of CBS is covered stent placement (CSP). Our initial experience in CSP is evaluated and compared with reports in the literature. METHODS: This study analysed 17 patients with HNC who had received CSP for CBS at Kaohsiung Medical University Chung-Ho Memorial Hospital from May 2005 to December 2013. The medical records and images for these patients were retrospectively reviewed to evaluate the causes of CBS, treatment success rates and complications. RESULTS: The initial angiography success rate was 100%. Procedural or periprocedural complications were noted in two (12%) cases, both suffering from cerebral vascular accident (CVA). Short-term complications were noted in eight (47%) cases, including four rebleeding cases and four CVA cases. Medium- to long-term complications were noted in nine cases, which included two asymptomatic in-stent thrombosis cases, one symptomatic CVA case, two abscess formation cases and four rebleeding cases. Overall, eight (47%) cases of rebleeding occurred during follow-up. Three of the eight cases were fatal, accounting for 27% of the all-cause mortality. CONCLUSION: Although CSP is considered effective for achieving haemostasis in patients with HNC with CBS, the medium- to long-term outcomes are unfavourable owing to high risks of rebleeding, CVA and other complications. Therefore, CSP should be considered a temporary life-saving technique rather than a definitive treatment. ADVANCES IN KNOWLEDGE: Analysis of the relatively large series of patients with HNC in this study suggests that CSP is a useful temporary treatment for CBS.

Cerebral metabolic changes in neurologically presymptomatic patients undergoing haemodialysis: in vivo proton MR spectroscopic findings.

OBJECTIVE: To prospectively investigate and detect early cerebral metabolic changes in patients with end-stage renal disease (ESRD) by using in vivo proton MR spectroscopy (MRS). METHODS: We enrolled 32 patients with ESRD and 32 healthy controls between the ages of 26 and 50 years. Short echo time single-voxel proton MRS was acquired from volumes of interest (VOIs) located in the frontal grey and white matter, temporal white matter and basal ganglia. The choline/phospatidylcholine (Cho), myo-inositol (mI), N-acetylaspartate (NAA) and total creatine (tCr) peaks were measured and the metabolic ratios with respect to tCr were calculated. RESULTS: In the ESRD group, significant elevations of the Cho/tCr and mI/tCr ratios were observed for the frontal grey matter, frontal white matter, temporal white matter and basal ganglia as compared with controls. There was no significant difference in the NAA/tCr ratios at all VOIs between the ESRD patients and the healthy controls. CONCLUSIONS: Proton MRS is a useful and non-invasive imaging tool for the detection of early cerebral metabolic changes in neurologically presymptomatic ESRD patients.

Proton magnetic resonance spectroscopy of late-life major depressive disorder.

The primary goal of this study was to examine the biochemical abnormalities of late-life major depression by using 3-tesla (3-T) proton magnetic resonance spectroscopy ((1)H-MRS). The antidepressant effects on the biochemical abnormalities were investigated as well. Study participants were 27 elderly patients with major depressive disorders (among which 9 were on antidepressant medication) and 19 comparison elderly subjects. (1)H-MRS spectra were acquired from voxels that were placed in the left frontal white matter, left periventricular white matter, and left basal ganglia. Ratios of N-acetylaspartate (NAA), choline (Cho) and myo-inositol to creatine were calculated. Patients with late-life major depressive disorder had a significantly lower NAA/creatine ratio in the left frontal white matter, and higher Cho/creatine and myo-inositol/creatine ratios in the left basal ganglia when compared with the control subjects. The myo-inositol correlated with global cognitive function among the patients. The biochemical abnormalities in late-life major depressive disorder were found on the left side of the frontal white matter and the basal ganglia. Neuron degeneration in the frontal white matter and second messenger system dysfunction or glial dysfunction in the basal ganglia are suggested to be associated with late-life depression.

Carotid intima-media thickness in late-onset major depressive disorder.

BACKGROUND: This study explored whether patients with late-onset major depressive disorder showed higher carotid artery intima-medium thickness (IMT) and investigated the relationship between the IMT and white matter hyperintensities on magnetic resonance imaging (MRI) among patients. METHODS: Fourteen elderly patients with late-onset major depressive disorder from a psychiatric outpatient clinic and 11 non-depressed controls received a comprehensive psychiatric assessment, ultrasound IMT measurements of the carotid arteries, and cerebral MRI. RESULTS: The carotid IMT was higher in the patient group vs the control group (1.26 +/- 0.30 vs 1.00 +/- 0.20 mm; t = 2.40, p < 0.03). The difference was more apparent in the common carotid artery (1.20 +/- 0.32 vs 0.97 +/- 0.13 mm; t = 2.31, p < 0.04). There was a high correlation (r = 0.55, p < 0.05) between the carotid IMT and white matter hyperintensities among patients with late-onset major depressive disorder. CONCLUSION: Results of this study suggest that atherosclerosis represented by the carotid IMT contributes to the development of late-onset major depressive disorder. The findings support the vascular depression hypothesis.

Multidetector row CT demonstration of inner and middle ear structures.

The aim of this study is to evaluate the anatomical details of the inner ear and middle ear, using multidetector row CT. Temporal bone CT scans were obtained using 16-detector row CT scanner (Lightspeed 16, General Electric Medical Systems, Milwaukee, WI) in 30 patients with dizziness, vertigo, or hearing loss. The three-dimensional (3D) images were reconstructed with volume rendering techniques. The 3D images were reviewed by two radiologists and scored by using a three-point quality rating for qualitative assessment of the 23 representative structures of the middle and inner ear. The malleus, incus, and facial nerve canal were identified in all patients. The incudomalleolar joint appeared fused in all patients. The stapes were seen clearly in 27 (90%) of 30 patients except in three patients. Among the three remaining patients, there was one who had effusions in the middle ear cavity. Another patient had left cholesteatoma. The third patient had normal middle ear cavity. The cochlea and the three semicircular canals (anterior, posterior, and lateral) were well demonstrated in 29 (97%) of 30 patients except for one old woman with osteoporosis. Sixteen-detector row CT imaging of temporal bone with advanced 3D reformation yields state-of-the-art anatomical details of the temporal region useful to address anatomical localization issues and ease conceptual structural learning.

Homocysteine levels, MTHFR C677T genotype, and MRI Hyperintensities in late-onset major depressive disorder.

OBJECTIVE: Epidemiological studies suggest that elevated plasma homocysteine is associated with an increased risk of depression and cerebrovascular disease. There are no published reports of homocysteine levels and methylenetetrahydrofolate reductase (MTHFR) C677T genotype in clinical samples of patients with late-onset major depressive disorder (MDD). The purpose of this study was to examine the association of homocysteine levels or MTHFR C677T genotype and late-onset MDD and assess whether this may be affected by brain magnetic resonance imaging (MRI) hyperintensities. METHODS: Authors recruited 39 elderly patients with MDD with first episode occurring after age 50 and 20 comparison subjects and assessed total plasma homocysteine levels, MTHFR genotype, and brain MRIs. RESULTS: Plasma total homocysteine levels were higher in elderly patients with late-onset MDD versus comparison subjects. The association did not change after controlling for MRI hyperintensities, and the distribution of MTHFR C677T genotype was not different between the groups. CONCLUSIONS: In this exploratory study, elevated homocysteine levels were associated with late-onset MDD, and the association did not appear to be mediated by vascular pathology as identified by brain MRI hyperintensities.

Structural abnormality on brain magnetic resonance imaging in late-onset major depressive disorder.

The purpose of this study was to examine the structural abnormalities of patients with late-onset major depressive disorder using brain magnetic resonance imaging (MRI) and to assess clinical correlates of these structural abnormalities. Thirty-seven elderly patients with DSM-IV major depressive disorder that first occurred after the age of 50 years, and 18 control subjects without depression were recruited. All participants underwent comprehensive psychiatric assessment and cerebral MRI. Brain ventricular and sulcal sizes and white matter hyperintensities were assessed visually. Relative to control subjects, patients with late-life major depressive disorder showed more severe brain atrophy (p = 0.043) and white matter hyperintensities (p = 0.024), especially in the periventricular area (p = 0.012). Over 60% of the patient group had significant brain MRI hyperintensities. White matter hyperintensity was correlated with later onset of depressive illness (r = 0.49, p = 0.002) among patients. Brain atrophy and white matter hyperintensities are prevalent in patients with late-onset major depressive disorders. These two abnormalities may represent different pathophysiologic processes of depressive disorders. White matter hyperintensities may be predisposing factors for late-onset major depressive disorder.

3-T proton magnetic resonance spectroscopy of central neurocytoma: 3 case reports and review of the literature.

Central neurocytoma (CNC), first described by Hassoun et al in 1982, is a rare neuronal tumor of the central nervous system, accounting for 0.25% to 0.5% of all central nervous system tumors. To our knowledge, there are only 5 published articles reporting the magnetic resonance spectroscopy (MRS) findings of neurocytomas. The 3-T proton MRS findings of 3 cases with CNC confirmed by immunohistochemical stains are reported here. Increased choline (Cho)/creatine (Cr) ratios with decreased N-acetylaspartate (NAA)/Cr ratios were observed in all 3 cases, but only 1 case had an increased peak at 3.55 ppm known as glycine (Gly). The other case with an increased alanine peak at 1.5 ppm had a poor prognosis. Therefore, we conclude that the presence of a Gly peak may suggest the diagnosis of CNC but that the absence of Gly does not exclude the diagnosis of CNC.

Detection of intracranial hemorrhage: comparison between gradient-echo images and b0 images obtained from diffusion-weighted echo-planar sequences on 3.0T MRI.

In this study, we compared the effectiveness of b0 echo-planar MR images (EPI) imaging with gradient recalled echo (GRE) in detecting acute hemorrhage. Brain images in 69 patients who suffered from acute infarction were reviewed. Nine of them had suffered from acute hemorrhage. Comparing b0EPI and GRE images side-by-side, we found no significant different effectiveness in detecting hemorrhage (P = .522, > or =.05). We concluded that b0EPI imaging could detect hemorrhagic lesions as effectively as GRE can without additional acquisition time.

Distinction between high-grade gliomas and solitary metastases using peritumoral 3-T magnetic resonance spectroscopy, diffusion, and perfusion imagings.

This study compared the effectiveness of relative cerebral blood volume, apparent diffusion coefficient, and spectroscopic imaging in differentiating between primary high-grade gliomas and solitary metastases. A 3.0-T MR unit was used to perform proton MR spectroscopy, diffusion imaging, and conventional MR imaging on 26 patients who had solitary brain tumors (14 high-grade gliomas and 12 metastases). All diagnoses were confirmed by biopsy. Twelve perfusion MR studies (8 high-grade gliomas and 4 metastases) were also performed. The results showed that the choline to creatine ratio and relative cerebral blood volume in the peritumoral regions of high-grade gliomas were significantly higher than they were in the metastases. The apparent diffusion coefficient values in tumoral and peritumoral regions of metastases were significantly higher than they were in the primary gliomas. Although conventional MR imaging characteristics of solitary metastases and primary high-grade gliomas may sometimes be similar, the peritumoral perfusion-weighted and spectroscopic MR imaging enable distinction between the two. Diffusion-weighted imaging techniques were complementary techniques to make a differential diagnosis between the two malignant tumors.

Chordoma mimicking the trigeminal schwannoma: a case report.

Intracranial chordomas are rare tumor arising from the remnants of embryologic notochord. Bony destruction and tumor calcification are their characters. Now we represent an extra-axial tumor with an unusual dumbbell shape in the right Meckel's cave and the appearance mimics the trigeminal schwannomas. However, the histopathological findings reveal a chordoma. Bony destruction in the right petrous bone and clivus provides a hint to make appropriate diagnosis.

Splenic abscesses: review of 29 cases.

Splenic abscess is an unusual and potentially life-threatening disease. Due to the nonspecific clinical picture, it remains a diagnostic challenge. Splenic abscess should be suspected in febrile patients with left upper quadrant tenderness and leukocytosis, and diagnosis confirmed based mostly on imaging studies, microbiologic and / or pathologic evidence, or by response to antibiotic or antifungal treatment. We present 29 cases of splenic abscess treated in our hospital from 1990 to 2001. There were 18 male patients (62%) and 11 female patients (38%). Ages ranged from 4 to 85 years, with a median of 44 years. There were five pediatric patients (17%) and 24 adults (83%). The most common associated condition was leukemia. Most patients were immunocompromised (72%). The more common signs and symptoms were fever (90%), chills (41%), abdominal pain (31%), and leukocytosis (38%). Ultrasonography of the abdominal cavity was positive in 27 cases (93%); computerized tomography or magnetic resonance imaging was used in 26 patients (90%) and was positive in all patients. The abscess was solitary in 21 cases (72%) and multiple in eight cases (28%). Positive blood cultures were found in only seven patients (24%). According to the literature, the treatment of choice is still splenectomy, but in our study, the success rate of 75% with antibiotics alone indicates that antibiotic therapy should be considered an important alternative treatment modality in patients not suitable for percutaneous drainage and splenectomy.

Effect of filmless imaging on utilization of radiologic services with a two-stage, hospital-wide implementation of a picture archiving and communication system: initial experience of a fee-for-service model.

A medium-sized general hospital using a fee-for-service model implemented a hospital-wide picture archiving and communication system (PACS) in two stages. This study evaluated the reporting time with filmless operation and the effect of filmless imaging on referring physicians' use of the radiologic service before and after completion of the second stage of PACS implementation. The relationship between the total number of hospital patients and the number of radiologic department patients was also evaluated. All sample images were retrieved from the PACS. All corresponding reports except for one for a computerized tomography study were available. The median reporting time for different studies performed during working hours was less than 2 hours. There was a significantly positive and linear relationship (p < 0.01) between the total number of hospital patients and the number of radiologic department patients after hospital-wide implementation of PACS. We conclude that the fee-for-service model had no negative impact on referring physicians' use of radiologic services in a filmless hospital.

Exogenous lipoid pneumonia: serial chest plain roentgenography and high-resolution computerized tomography findings.

Between May 1988 and July 2002, six patients with pneumonia due to diesel, animal, or vegetable oil aspiration were admitted to Kaohsiung Medical University Hospital. The purpose of this study was to demonstrate distinctive radiographic findings of oil-induced lipoid pneumonitis on initial serial chest roentgenograms and high-resolution computerized tomography (CT) scans. Initial chest roentgenograms (n = 6), CT scans (n = 6), and roentgenography and CT follow-up studies were analyzed retrospectively by two chest radiologists and two surgeons, focusing on the pattern and distribution of parenchymal abnormalities. The most common location was the right middle lobe, followed by the right lower lobe, the left lower lobe, and the lingular lobe. Follow-up chest roentgenograms (n = 6) showed complete disappearance of the parenchymal lesions in only one patient and partial decrease in the extent of lesions in five patients. Lipoid pneumonia presents non-specific findings on chest roentgenography. It is commonly located in both lower and the right middle lobes. On high-resolution CT, the lesions appear most commonly as areas of consolidation, ground-glass attenuation mixed with paving pattern, and poorly defined nodules.

Spontaneous retroperitoneal biloma: a case report.

We report a rare case of spontaneous rupture of the biliary tree with biloma in the retroperitoneum. A 74-year-old man was admitted with back pain and general weakness. Computerized tomography (CT) and sonography showed a huge lesion in the right retroperitoneum, and a diagnosis of biloma was made after percutaneous aspiration. A percutaneous drainage catheter was initially inserted into the right retroperitoneal lesion under sonographic guidance to treat the biloma because of high surgical risk. When his general condition had improved, the patient underwent cholecystectomy and removal of the common bile duct stone; there was no evidence of leakage in the extrahepatic bile duct. Non-surgical intervention before definitive biliary surgery is considered the first choice for treating bilomas in high-risk patients.