Current Issue : October - December Volume : 2016 Issue Number : 4 Articles : 5 Articles
Purpose. Quantitative cerebral blood flow(CBF) measurement using dynamic susceptibility contrast- (DSC-) MRI requires accurate\nestimation of the arterial input function (AIF). The present work utilized the independent component analysis (ICA) method to\ndetermine the AIF in the regions adjacent to the middle cerebral artery (MCA) by the alleviated confounding of partial volume\neffect. Materials and Methods. A series of spin-echo EPI MR scans were performed in 10 normal subjects. All subjects received\n0.2mmol/kg Gd-DTPA contrast agent. AIFs were calculated by two methods: (1) the region of interest (ROI) selected manually\nand (2) weighted average of each component selected by ICA (weighted-ICA). The singular value decomposition (SVD) method\nwas then employed to deconvolve the AIF from the tissue concentration time curve to obtain quantitative CBF values. Results.The\nCBF values calculated by the weighted-ICA method were 41.1 Ã?± 4.9 and 22.1 Ã?± 2.3 mL/100 g/min for cortical gray matter (GM)\nand deep white matter (WM) regions, respectively. The CBF values obtained based on the manual ROIs were 53.6 Ã?± 12.0 and\n27.9 Ã?± 5.9 mL/100 g/min for the same two regions, respectively. Conclusion. The weighted-ICA method allowed semiautomatic and\nstraightforward extraction of the ROI adjacent toMCA. Through eliminating the partial volume effect to minimum, the CBF thus\ndetermined may reflect more accurate physical characteristics of the T2âË?â?? signal changes induced by the contrast agent....
Making a confident diagnosis is a complex task for a specific form of interstitial lung disease and\nproviding appropriate management in an attempt to achieve normalization of the disease can put\nup an alarming process for the clinicians. A set of diffuse and restrictive lung diseases incorporate\nwith idiopathic interstitial pneumonias, showing inflammation and fibrosis of the interstitium due\nto parenchymal damage. High-resolution computed tomography (HRCT) has magnified the diagnostic\nstandpoint in stepwise identification and classified various patterns in the evaluation of interstitial\nlung disease. The aim of our review is to elaborate clinical, radiographic and typical and\natypical HRCT findings of idiopathic interstitial pneumonias by correlating with its differential\ndiagnosis. Idiopathic pulmonary fibrosis is the most predominant idiopathic interstitial pneumonias\nand its diagnosis needs to omit all other well-known causes of interstitial lung diseases. According\nto the 2011 evidence-based guidelines, usual interstitial pneumonia can be diagnosed by\nHRCT when all criteria are fulfilled. Non-specific interstitial pneumonia is distinguished by bilateral\npatchy ground-glass opacities and irregular linear/reticular opacities. Respiratory bronchiolitis\nassociated-interstitial lung disease and desquamative interstitial pneumonia show centrolobular\nnodules and ground-glass opacities as imaging patterns. Cryptogenic organizing pneumonia\nconsists of patchy peripheral or peribronchial consolidations, while ground-glass opacities\nwith tendency for migration, which is evolving to fibrosis, in acute interstitial pneumonia. Lymphoid\ninterstitial pneumonia and idiopathic pleuro-parenchymal fibroelastosis are classified under\nrare idiopathic interstitial pneumonias. HRCT images help radiologists in diagnosis and mapping\nspecific patterns of idiopathic interstitial pneumonias. This article reviews the stages of evolution\nin HRCT features for idiopathic interstitial pneumonias....
Objectives. The aim of this study was to detect factors associated with small bowel obstruction (SBO) caused by bezoars on\nmultidetector computed tomographic findings. Methods. We retrospectively reviewed 61 patients who had bezoars in the small\nbowels on MDCT. The patients were divided into SBO patients group and non-SBO patients group. The mean values of the\ndiameter, volume, and CT attenuation as well as location and characteristics of the bezoars were compared between the two groups.\nMultivariate analysis was performed to determine factors associated with SBO. Results.There were 32 patients (52.5%) in the SBO\ngroup and 29 patients (47.5%) in the non-SBO group. The bezoars in the SBO group had greater values of each mean diameter and\nmean volume than those in the non-SBO group (3.2 �± 0.5 cm versus 1.6 �± 0.7 cm, P < 0.0001, 14.9 �± 6.4 cm3 versus 2.5 �± 2.7 cm3,\nP < 0.0001, resp.) and had a lower CT attenuation than the non-SBO group (55.5 �± 23.4 versus 173.0 �± 68.0, P < 0.0001). The\nSBO group had higher prevalence of phytobezoar appearance (75.0% versus 10.3%, P < 0.0001). Major diameters of bezoar and\nphytobezoar were significant independent risk factors associated with SBO (odds ratio = 36.09, 8.26, resp., and P = 0.0004, 0.044,\nresp.). Conclusions. Major diameter of bezoar or phytobezoar is a potential risk factor associated with SBO....
Purpose: To evaluate posthepatectomy liver failure (PHLF) using gadoxetic acid-enhanced magnetic\nresonance imaging (MRI) with a measure of relative liver enhancement (RLE) on hepatobiliary\nphase images, thereby facilitating safe liver resection. Methods: Twenty patients in Child-\nPugh class A underwent tumor excision surgery and indocyanine green (ICG) clearance of future\nremnant liver (FRL) (ICG-Krem) values were >0.05. PHLF was evaluated using the grading system\nof the International Study Group of Liver Surgery (ISGLS). The RLE value was defined as the signal\ngain percentage between the precontrast and hepatocellular images. In the whole liver and FRL,\ntheRLE value measured the tumor-free liver parenchyma in RLE images. We examined the correlation\nbetween indocyanine green clearance (ICG-K) and MRI-based liver function in the whole\nliver. Preoperative PHLF evaluation was predicted using remnant hepatocellular uptake index\n(rHUI), remnant RLE (rRLE), coefficient variation of Rrle [Cv(rRLE)], and ICG-Krem corrected by\nheterogeneous liver function(HLF-ICG-Krem). Results: HLF-ICG-Krem and rRLE values correlated\nwith INRs after postoperative day five (r = âË?â??0.55 and 0.46, p = 0.01 and 0.04, respectively). Furthermore,\nHLF-ICG-Krem values ââ?°Â¤0.05 detected two patients with higher INRs after postoperative\nday five. On the other hand, neither rHUI nor Cv(rRLE) was correlated with INRs after postoperative day five (r = 0.28, and âË?â??0.03, respectively; p > 0.05 for both). HLF-ICG-Krem was significantly lower\nwith PHLF than without PHLF (p = 0.005). Conclusion: HLF-ICG-Krem is useful for evaluating PHLF\nmore correctly....
Background: Correlating symptoms and physical examination findings with surgical levels based on common\nimaging results is not reliable. In patients who have no concordance between radiological and clinical symptoms,\nthe surgical levels determined by conventional magnetic resonance imaging (MRI) and neurogenic examination\n(NE) may lead to a more extensive surgery and significant complications. We aimed to confirm that whether the\nuse of diffusion tensor imaging (DTI) and paraspinal mapping (PM) techniques can further prevent the occurrence\nof false positives with conventional MRI, distinguish which are clinically relevant from levels of cauda equina\nand/or nerve root lesions based on MRI, and determine and reduce the decompression levels of lumbar\nspinal stenosis than MRI + NE, while ensuring or improving surgical outcomes.\nMethods: We compared the data between patients who underwent MRI + (PM or DTI) and patients who\nunderwent conventional MRI + NE to determine levels of decompression for the treatment of lumbar spinal\nstenosis. Outcome measures were assessed at 2 weeks, 3 months, 6 months, and 12 months postoperatively.\nResults: One hundred fourteen patients (59 in the control group, 54 in the experimental group) underwent\ndecompression. The levels of decompression determined by MRI + (PM or DTI) in the experimental group\nwere significantly less than that determined by MRI + NE in the control group (p = 0.000). The surgical time,\nblood loss, and surgical transfusion were significantly less in the experimental group (p = 0.001, p = 0.011, p = 0.001,\nrespectively). There were no differences in improvement of the visual analog scale back and leg pain (VAS-BP, VAS-LP)\nscores and Oswestry Disability Index (ODI) scores at 2 weeks, 3 months, 6 months, and 12 months after operation\nbetween the experimental and control groups.\nConclusions: MRI + (PM or DTI) showed clear benefits in determining decompression levels of lumbar spinal stenosis\nthan MRI + NE. In patients with lumbar spinal stenosis, the use of PM and DTI techniques reduces decompression\nlevels and increases safety and benefits of surgery....
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