Ultrafast 3d spin-echo acquisition improves gadolinium-enhanced mri signal contrast enhancement

Long scan times of 3D volumetric MR acquisitions usually necessitate ultrafast in vivo gradient-echo acquisitions, which are intrinsically susceptible to magnetic field inhomogeneities. This is especially problematic for contrast-enhanced (CE)-MRI applications, where non-negligible T 2 & z.ast; effect of contrast agent deteriorates the positive signal contrast and limits the available range of MR acquisition parameters and injection doses. To overcome these shortcomings without degrading temporal resolution, ultrafast spin-echo acquisitions were implemented. Specifically, a multiplicative acceleration factor from multiple spin echoes (??32) and compressed sensing (CS) sampling (??8) allowed highly-accelerated 3D Multiple-Modulation- Multiple-Echo (MMME) acquisition. At the same time, the CE-MRI of kidney with Gd-DOTA showed significantly improved signal enhancement for CS-MMME acquisitions (??7) over that of corresponding FLASH acquisitions (??2). Increased positive contrast enhancement and highly accelerated acquisition of extended volume with reduced RF irradiations will be beneficial for oncological and nephrological applications, in which the accurate in vivo 3D quantification of contrast agent concentration is necessary with high temporal resolution.open0

Expression of the phosphorylated MEK5 protein is associated with TNM staging of colorectal cancer

<p>Abstract</p> <p>Background</p> <p>Activation of MEK5 in many cancers is associated with carcinogenesis through aberrant cell proliferation. In this study, we determined the level of phosphorylated MEK5 (pMEK5) expression in human colorectal cancer (CRC) tissues and correlated it with clinicopathologic data.</p> <p>Methods</p> <p>pMEK5 expression was examined by immunohistochemistry in a tissue microarray (TMA) containing 335 clinicopathologic characterized CRC cases and 80 cases of nontumor colorectal tissues. pMEK5 expression of 19 cases of primary CRC lesions and paired with normal mucosa was examined by Western blotting. The relationship between pMEK5 expression in CRC and clinicopathologic parameters, and the association of pMEK5 expression with CRC survival were analyzed respectively.</p> <p>Results</p> <p>pMEK5 expression was significantly higher in CRC tissues (185 out of 335, 55.2%) than in normal tissues (6 out of 80, 7.5%; <it>P </it>< 0.001). Western blotting demonstrated that pMEK5 expression was upregulated in 12 of 19 CRC tissues (62.1%) compared to the corresponding adjacent nontumor colorectal tissues. Overexpression of pMEK5 in CRC tissues was significantly correlated to the depth of invasion (<it>P </it>= 0.001), lymph node metastasis (<it>P </it>< 0.001), distant metastasis (<it>P </it>< 0.001) and high preoperative CEA level (<it>P </it>< 0.001). Consistently, the pMEK5 level in CRC tissues was increased following stage progression of the disease (<it>P </it>< 0.001). Analysis of the survival curves showed a significantly worse 5-year disease-free (<it>P </it>= 0.002) and 5-year overall survival rate (<it>P </it>< 0.001) for patients whose tumors overexpressed pMEK5. However, in multivariate analysis, pMEK5 was not an independent prognostic factor for CRC (DFS: <it>P </it>= 0.139; OS: <it>P </it>= 0.071).</p> <p>Conclusions</p> <p>pMEK5 expression is correlated with the staging of CRC and its expression might be helpful to the TNM staging system of CRC.</p

Role of tumor size in the pre-operative management of rectal cancer patients

Clinical management of rectal cancer patients relies on pre-operative staging. Studies however continue to report moderate degrees of over/understaging as well as inter-observer variability. The aim of this study was to determine the sensitivity, specificity and accuracy of tumor size for predicting T and N stages in pre-operatively untreated rectal cancers

Magnetic resonance imaging (MRI) in rectal cancer: a comprehensive review

Magnetic resonance imaging (MRI) has established itself as the primary method for local staging in patients with rectal cancer. This is due to several factors, most importantly because of the ability to assess the status of circumferential resection margin. There are several newer developments being introduced continuously, such as diffusion-weighted imaging and imaging with 3 T. Assessment of loco-regional lymph nodes has also been investigated extensively using different approaches, but more work needs to be done. Finally, evaluation of tumours during or after preoperative treatment is becoming an everyday reality. All these new aspects prompt a review of the most recent advances and opinions. In this review, a comprehensive overview of the current status of MRI in the loco-regional assessment and management of rectal cancer is presented. The findings on MRI and their accuracy are reviewed based on the most up-to-date evidence. Optimisation of MRI acquisition and relevant regional anatomy are also presented, based on published literature and our own experience

Benign external hydrocephalus: a review, with emphasis on management

Benign external hydrocephalus in infants, characterized by macrocephaly and typical neuroimaging findings, is considered as a self-limiting condition and is therefore rarely treated. This review concerns all aspects of this condition: etiology, neuroimaging, symptoms and clinical findings, treatment, and outcome, with emphasis on management. The review is based on a systematic search in the Pubmed and Web of Science databases. The search covered various forms of hydrocephalus, extracerebral fluid, and macrocephaly. Studies reporting small children with idiopathic external hydrocephalus were included, mostly focusing on the studies reporting a long-term outcome. A total of 147 studies are included, the majority however with a limited methodological quality. Several theories regarding pathophysiology and various symptoms, signs, and clinical findings underscore the heterogeneity of the condition. Neuroimaging is important in the differentiation between external hydrocephalus and similar conditions. A transient delay of psychomotor development is commonly seen during childhood. A long-term outcome is scarcely reported, and the results are varying. Although most children with external hydrocephalus seem to do well both initially and in the long term, a substantial number of patients show temporary or permanent psychomotor delay. To verify that this truly is a benign condition, we suggest that future research on external hydrocephalus should focus on the long-term effects of surgical treatment as opposed to conservative management

Maxillary sinus inflammatory disease: Ultrasound compared to computed tomography

Fifty-six patients (age range, 15-79 yr, average, 37.0±18.5 yr), with a clinical and/or radiological diagnosis of acute maxillary sinusitis, were prospectively studied with ultrasound (US) and computed tomography (CT). The imaging finding which supported the diagnosis of acute sinusitis with US was the identification of the hyperechoic posterior antral wall through the hypoechoic inflammation. The findings were compared to CT (3 mm axial sections). The sensitivity of US for maxillary sinus disease was found to be 66.7% and the specificity was 94.9%, which were similar to the plain film ones (65.2 and 96.8%, respectively). The results of the present study suggest US as the method of first choice for acute sinusitis of the maxillary antra, particularly for children and pregnant women. Fifty-six patients (age range, 15-79 yr, average, 37.0±18.5 yr), with a clinical and/or radiological diagnosis of acute maxillary sinusitis, were prospectively studied with ultrasound (US) and computed tomography (CT). The imaging finding which supported the diagnosis of acute sinusitis with US was the identification of the hyperechoic posterior antral wall through the hypoechoic inflammation. The findings were compared to CT (3 mm axial sections). The sensitivity of US for maxillary sinus disease was found to be 66.7% and the specificity was 94.9%, which were similar to the plain film ones (65.2 and 96.8%, respectively). The results of the present study suggest US as the method of first choice for acute sinusitis of the maxillary antra, particularly for children and pregnant women

Osteoid Osteoma of the Femoral Neck: Use of the Half-Moon Sign in MRI Diagnosis

OBJECTIVE. Osteoid osteoma is a benign bone tumor that is commonly located in the proximal femur. Although CT is helpful in the diagnosis of osteoid osteoma, patients in whom the clinical presentation of the tumor is atypical are first referred to undergo MRI, which yields a high percentage of false-negative or inconclusive results. We sought to explore the association between a half-moon sign of bone marrow edema and the presence of osteoid osteoma of the femoral neck. SUBJECTS AND METHODS. The MRI examinations of 11 consecutive patients with osteoid osteoma (group 1) were prospectively included in the study. In addition, 950 consecutive hip MRI examinations of 485 patients were retrospectively analyzed for the presence of bone marrow edema of the femoral neck, with 19 patients identified as having bone marrow edema resulting from causes other than osteoid osteoma (group 2). Patients in both study groups were evaluated for the presence of the half-moon sign. RESULTS. The half-moon sign of bone marrow edema was significantly associated with the presence of osteoid osteoma (p < 0.0001), having been seen on the MR images of all 11 patients in group 1 and only one of 19 patients in group 2. MRI examination was therefore 94.7% specific and 100% sensitive for the detection of osteoid osteoma, with positive and negative predictive values of 91.7% and 100%, respectively. CONCLUSION. The half-moon sign is an MRI finding that is highly specific and sensitive for an accurate diagnosis of osteoid osteoma of the femoral neck

Software upgrading in a CT scanner: Influence on quantitative CT

Purpose: In an attempt to improve field uniformity and CT number stability, the software in a CT scanner was replaced with a new version. The purpose of the present study was to investigate the influence of the software upgrading on density measurements. Material and Methods: The upgrading influence was investigated by means of a torso phantom (European spinal). The phantom simulates a torso which contains 3 vertebrae of different densities. Results: Despite the use of a reference standard under the phantom, the software change resulted in: a) improved short-term precision; b) increased density values at 80 and 100 kVp, decreased at 130 kVp; and c) increased influence of the kVp on the values. Conclusion: The results of the present study suggest that conversion factors have to be used in density values for reference populations as well as in the values of patients undergoing follow-up studies

Hip osteoarthritis: What the radiologist wants to know

Osteoarthritis (OA) is the most common disease of the hip joint seen in adults. The diagnosis of OA is based on a combination of radiographic findings of joint degeneration and characteristic subjective symptoms. The lack of a radiographic consensus definition has resulted in a variation of the published incidences and prevalence of OA. The chronological sequence of degeneration includes the following plain radiographic findings: joint space narrowing, development of osteophytes, subchondral sclerosis, and cyst formation. There are cases though, that plain radiographs show minor changes and the clinical suspicion of early disease can be confirmed with more sophisticated imaging methods, such as multi-detector computed tomography and MR imaging. The present article will review all the clinical information on the hip OA together with an updated radiological approach, with emphasis on the early depiction and the differential diagnosis of the disease. (c) 2007 Elsevier Ireland Ltd. All rights reserved