Chemical shift encoded water–fat separation using parallel imaging and compressed sensing

Chemical shift encoded techniques have received considerable attention recently because they can reliably separate water and fat in the presence of off‐resonance. The insensitivity to off‐resonance requires that data be acquired at multiple echo times, which increases the scan time as compared to a single echo acquisition. The increased scan time often requires that a compromise be made between the spatial resolution, the volume coverage, and the tolerance to artifacts from subject motion. This work describes a combined parallel imaging and compressed sensing approach for accelerated water–fat separation. In addition, the use of multiscale cubic B‐splines for B₀ field map estimation is introduced. The water and fat images and the B₀ field map are estimated via an alternating minimization. Coil sensitivity information is derived from a calculated k‐space convolution kernel and l₁‐regularization is imposed on the coil‐combined water and fat image estimates. Uniform water–fat separation is demonstrated from retrospectively undersampled data in the liver, brachial plexus, ankle, and knee as well as from a prospectively undersampled acquisition of the knee at 8.6x acceleration. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.     

Three‐dimensional first‐pass myocardial perfusion MRI using a stack‐of‐spirals acquisition

Three‐dimensional cardiac magnetic resonance perfusion imaging is promising for the precise sizing of defects and for providing high perfusion contrast, but remains an experimental approach primarily due to the need for large‐dimensional encoding, which, for traditional 3DFT imaging, requires either impractical acceleration factors or sacrifices in spatial resolution. We demonstrated the feasibility of rapid three‐dimensional cardiac magnetic resonance perfusion imaging using a stack‐of‐spirals acquisition accelerated by non‐Cartesian k‐t SENSE, which enables entire myocardial coverage with an in‐plane resolution of 2.4 mm. The optimal undersampling pattern was used to achieve the largest separation between true and aliased signals, which is a prerequisite for k‐t SENSE reconstruction. Flip angle and saturation recovery time were chosen to ensure negligible magnetization variation during the transient data acquisition. We compared the proposed three‐dimensional perfusion method with the standard 2DFT approach by consecutively acquiring both data during each R–R interval in cardiac patients. The mean and standard deviation of the correlation coefficients between time intensity curves of three‐dimensional versus 2DFT were 0.94 and 0.06 across seven subjects. The linear correlation between the two sets of upslope values was significant (r = 0.78, P < 0.05). Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.     

Cystic fibrosis and the phenotypic expression of autosomal dominant polycystic kidney disease

Recent experiments in cultured cyst epithelial cells from kidneys of patients with autosomal dominant polycystic kidney disease (ADPKD) have shown that the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) is present in the apical surface of these cells and mediates chloride (Cl-) and fluid secretion in vitro. To determine whether the presence of CF with the expression of mutated CFTR proteins modifies cyst formation in ADPKD, we studied a large family with both inherited diseases. ADPKD in this family is linked to PKD1. The family is composed of 26 members; 11 members with ADPKD, 4 members with CF, and 2 members with both diseases. Renal volumes measured by computerized tomography (CT), calculated creatinine clearances, and other clinical parameters in the family members with ADPKD and CF were compared with those in the family members with ADPKD alone, as well as to a large population of patients with ADPKD. The patients with CF and ADPKD, but not the CF heterozygote carriers with ADPKD, had less severe polycystic kidney and liver disease, as indicated by normal renal function; smaller renal volume, even when corrected for height and body surface area; and the absence of hypertension and liver cysts. These observations suggest that the coexistence of CF may reduce the severity of ADPKD.     

Myocutaneous v/s micro vascular free flaps in oral cavity reconstruction - a comparative study

Micro vascular free tissue transfer scores over the traditional myocutaneous flaps by providing better cosmesis and function. However, the increased operating tine and costs and the necessity for two operating teams sometimes, negate these advantages and even where this facility is freely available, myoentancous flaps continue to be widely used. To determine the ideal choice of reconstruction in patients after oral resection, we compared our experience with these two methods of reconstruction. Since 1997, when we first started micro vascular reconstruction, 17 patients have undergone this procedure for oral reconstruction. During this same period, 40 patients had pectoralis major myocutaneous flap reconstruction of the oral cavity. These two groups are compared with regard to cosmetic and functional results (as measured by patient’s level of satisfaction) operating time, duration of hospitalization, cost and complications. Results: Eightv seven percent of the patients in the micro vascular group and 75% in the myocutaneous group were satisfied with the cosmetic and functional results. In the microvascular group, average operating time was increased by 4 hours; hospitalization by 3 days and average cost of treatment was doubled. Flap failures and re-explorations were significantly higher in the micro vascular group. Based on these results, we would like to suggest the ideal method of reconstruction of the oral cavity in specific subgroups of patients in a corporate hospital setting.     

Cholecystocolic Fistula: A Diagnostic Enigma

Cholecystocolic fistula is a rare biliary-enteric fistula with a variable clinical presentation. Despite modern diagnostic tools, a high degree of suspicion is required to diagnose it preoperatively. Biliary-enteric fistulae have been found in 0.9% of patients undergoing biliary tract surgery. The most common site of communication of the fistula is a cholecystoduodenal (70%), followed by cholecystocolic (10–20%), and the least common is the cholecystogastric fistula accounting for the remainder of cases. These fistulae are treated by open as well as laparoscopic surgery, with no difference in intraoperative and postoperative complications.We report here a case of obstructive jaundice, which was investigated with a plain film of the abdomen, abdominal ultrasonography, and endoscopic retrograde cholangiopancreatography, but none of these gave us any clue to the presence of the fistula was discovered incidentally during an open surgery and was appropriately treated.     

Evaluation of the inflammatory response in sera from acute ischemic stroke patients by measurement of IL-2 and IL-10

Objectives  

We compared the concentrations of the proinflammatory cytokine interleukin-2 (IL-2) with the anti-inflammatory cytokine interleukin-10 (IL-10) in serial serum samples from improved and expired acute ischemic stroke (AIS) patients to determine their prognostic usefulness.     

Risk factors for posterior reversible encephalopathy syndrome in hypertensive pregnant women presenting with seizures

Neurological Sciences - Pregnant women developing generalised tonic–clonic seizures in the absence of a prior neurological disorder are often diagnosed as eclamptic. Posterior reversible...