Sinogram-based super-resolution in PET

Spatial resolution is intrinsically limited in positron emission tomography (PET) systems, mainly due to the crystal width. To increase the spatial resolution for a given crystal width, mechanical movements such as wobble and dichotomic motions are introduced to the PET systems. However, multiple sinograms obtained through such movements provide oversampled data. In this paper, to increase the spatial resolution, we present a novel super-resolution (SR) scheme that employs multiple sinograms. For SR, we first propose a blur kernel estimation scheme through a Monte Carlo simulation. Based on the estimated blur kernel, we adopt a maximum a posteriori expectation maximization method in estimating a high-resolution sinogram from multiple low-resolution sinograms. The proposed algorithm provides noticeable improvement of the spatial resolution in real PET images.     

GnRH Agonist Therapy in a Patient with Recurrent Ovarian Granulosa Cell Tumors

A 65-yr-old woman presented 17 yr status post-hysterectomy with bilateral ovarian salpingo-oophorectomy, attributable to ovarian cancer. She was admitted to our hospital, with multiple cystic liver masses and multiple large seeded masses in her abdomen and pelvic cavity. Histological examination of the pelvic masses demonstrated granulosa cell tumors. After two courses of systemic combination chemotherapy, with paclitaxel and carboplatin, the masses in the abdomen and pelvic cavity increased, and debulking surgery also failed because of peritoneal dissemination with severe adhesion. Finally, she underwent palliative radiotherapy for only the pelvic masses obstructing the urinary and GI tracts, and monthly hormonal therapy with a gonadotrophin-releasing hormone agonist; leuprorelin 3.75 mg IM. Subsequently, multiple masses beyond the range of the radiation as well as those within the radiotherapy field partially decreased. This partial response had been maintained for more than 8 months as of the last follow-up visit. Owing to its long and indolent course and the low metabolic rate of the tumors, advanced or recurrent granulosa cell tumor (GCT) requires treatment options beyond chemotherapy, surgery, and radiotherapy. Hormonal agents may provide another treatment option for advanced or recurrent GCT in those who are not candidates for surgery, chemotherapy, or radiotherapy.     

Endovascular treatment for transplant renal artery stenosis: A retrospective cohort study

Transplant renal artery stenosis (TRAS) is the most common (1%–23%) vascular complication following kidney transplantation. The aim of this study was to review our experience with an endovascular approach to treat TRAS.We retrospectively reviewed kidney transplant recipients who underwent percutaneous transluminal angioplasty (PTA) due to TRAS in our institute from January 2009 to December 2015. We analyzed the patient''s baseline characteristics, postoperative renal function, blood pressure evolution, and the number of pre- and post-procedure antihypertensive drugs.A total of 21 patients (15 men, 6 women) were treated with the endovascular technique. The predominant presentation was graft dysfunction (76.2%). Stenosis or hemodynamic kinking was located at the anastomosis in 7 (33.3%) patients, proximal to the anastomosis in 13 (61.9%) patients, and distal the anastomosis in 1 (4.8%) patient. PTA without stent placement was performed in 7 patients (33.3%), and PTA with stent placement was performed in 14 patients (67.7%). Serum creatinine levels demonstrated no difference between the pre-procedure level and that on discharge day (1.61 mg/dl [0.47–3.29 mg/dl] vs 1.46 mg/dl [0.47–3.08 mg/dl]; P = .33). The glomerular filtration rate also showed no difference between the pre-procedure value and that on discharge day (53.6 ml/min [22.4–145.7 ml/min] vs 57.0 ml/min [17.56 –145 ml/min]; P = .084). Systolic blood pressure and diastolic blood pressure (DBP) varied from 137 mm Hg (120–160 mm Hg) and 84 mm Hg (70–100 mm Hg) pre-procedure to 129 mm Hg (90–150 mm Hg) and 79 mm Hg (60–90 mm Hg) at discharge, respectively (P = .124 and P = .07). The number of antihypertensive medications significantly decreased from 1.5 (0–6) pre-procedure to 0.5 (0–2) at discharge (P = .023). In our study, there were no technical failures, procedure-related complications or deaths. During the follow-up period, the free-from-reintervention rate was 100%, and graft failures occurred in 2 patients (9.5%) due to rejection.Endovascular procedures for TRAS show a high technical success rate with a low complication rate and a low reintervention rate. PTA showed a trend toward a positive impact on lowering serum creatinine, systolic blood pressure, and diastolic blood pressure and improving estimated glomerular filtration rate, and the number of antihypertensive medications could be significantly reduced after this procedure.     

Miniscrew‐anchored alveolar distraction for the treatment of the ankylosed maxillary central incisor

Abstract – This report presents the case of a 20‐year‐old female patient exhibiting an infraoccluded ankylosed maxillary central incisor that was avulsed and replanted after traumatic injury during childhood. To reposition the osseous and gingival margins of the ankylosed tooth to an ideal level, a new alveolar distraction device that uses anchoring miniscrews with a single tooth dento‐osseous osteotomy was fabricated and the ankylosed tooth was successfully treated with exceptional patient compliance.     

A profile of the online dissemination of national influenza surveillance data

Background  

Influenza surveillance systems provide important and timely information to health service providers on trends in the circulation of influenza virus and other upper respiratory tract infections. Online dissemination of surveillance data is useful for risk communication to health care professionals, the media and the general public. We reviewed national influenza surveillance websites from around the world to describe the main features of surveillance data dissemination.