A Prototype of a Stereoacuity Test Using a Head-Mounted Display

Purpose@#To evaluate the test-retest reliability of a contour-based stereoacuity test using a head-mounted display (HMD) and compare it with other stereotests. @*Methods@#Thirty-two healthy adults aged 23-47 years were recruited from a tertiary hospital between August 2017 and July 2018. Two separate contour-based circles (crossed disparity: 135-1,350 arcsecs) were generated on a high-resolution phone display (Galaxy S7; Samsung, Seoul, Korea) using an HMD (Galaxy Gear VR). Two images were independently projected to each eye as graded circles with a random dot background. The results of the new HMD stereotest were compared to those of the standard Randot and TNO stereotests. The test-retest reliability was assessed using the Bland-Altman plot and Cohen’s kappa statistics. @*Results@#Among the 32 study participants, 17 (53%) were males and the mean age was 30.1 ± 4.8 years (range: 23-47). The mean stereoacuity was 160.3 ± 53.5 arcsecs in the first HMD stereotest (HMD1), 28.4 ± 12.5 arcsecs in the Randot stereotest, 96.1 ± 83.5 arcsecs in the TNO stereotest, and 143.3 ± 47.7 arcsecs in the second HMD stereotest (HMD2). The Bland-Altman plot showed a mean difference of 0.042 (-0.189 to +0.272, 95% limits of agreement) between HMD1 and HMD2. The reliability analysis showed an intraclass correlation coefficient of 0.499 (p = 0.022) and agreement of 81.25% in Cohen’s kappa statistics (Cohen’s kappa index = 0.119, p = 0.017). @*Conclusions@#The HMD stereotest without monocular cues showed fair test-retest reliability and reproducibility. Further studies using a high resolution display are needed to confirm the validity of the HMD stereotest.

The Effect of Adalimumab in Korean Patients with Refractory Noninfectious Uveitis

We sought to analyze the efficacy of adalimumab in active noninfectious uveitis, and evaluate its efficacy and safety for the management of refractory noninfectious uveitis in Korean patients. A retrospective observational study was conducted. A total of 23 eyes of 14 Korean patients with noninfectious uveitis refractory to conventional treatment, including corticosteroid and immunosuppressive agents, were treated with adalimumab between December 2017 and February 2020. The primary outcomes were vitreous haziness grades, anterior chamber cell grades, and central macular thickness measured prior to injection and at 1, 3, 6, and 12 months after the first adalimumab injection. Among the 23 eyes, 14 eyes (60.9%) were diagnosed with panuveitis and 9 eyes (39.1%) with posterior uveitis [mean follow-up period: 22.3 months (7–27)]. The most common etiologic diagnoses requiring adalimumab injection were Behçet's disease (9 eyes, 39.1%), followed by undifferentiated inflammation (6 eyes, 26.1%), Vogt-Koyanagi-Harada disease (3 eyes, 13.0%), psoriasis (2 eyes, 8.7%), serpiginous chorioretinopathy (2 eyes, 8.7%), and systemic lupus erythematosus (1 eye, 4.3%). At the 1-year follow-up after the first injection, anterior chamber cell grade decreased from 0.5±0.4 to 0.3±0.4, and vitreous haziness grade decreased from 1.1±1.1 to 0.3±0.5 (p<0.05). Central macular thickness improved from 347.2±98.1 µm to 264.3±61.1 µm (p<0.05). Adalimumab injection in patients with refractory noninfectious uveitis decreased the anterior chamber cell grade, vitreous haziness grade, and central macular thickness with no severe side effect. Overall, adalimumab injection may, therefore, be an effective and relatively safe treatment modality for noninfectious uveitis in Korean patients.

Effectiveness and stability of robot-assisted anastomosis in minimally invasive pancreaticoduodenectomy

Purpose@#Reconstruction using robotic assistance in pancreaticoduodenectomy (PD) was expected to be an effective means to overcome the limitations of laparoscopic surgery. To our knowledge, few comparative reports exist on the outcomes of totally laparoscopic PD (TLPD) and robot-assisted laparoscopic PD (RLPD). This retrospective study aimed to analyze the surgical results of TLPD and RLPD in a high-volume pancreatic center. @*Methods@#We analyzed the surgical results of consecutive patients who underwent a minimally invasive PD for malignant or benign periampullary lesions between January 2016 and May 2020. Forty-three TLPD patients and 49 RLPD patients were enrolled. @*Results@#There were no significant differences in the demographic characteristics between the 2 groups except for tumor size, which was significantly larger in the RLPD group than in the TLPD group (mean, 3.1 cm vs. 2.5 cm; P = 0.035).The RLPD group had shorter whole operative times (mean, 400.4 minutes vs. 352.2 minutes; P = 0.003) and shorter anastomosis times than the TLPD group (mean, 94.5 minutes vs. 54.9 minutes; P < 0.001). There was no significant difference between the 2 groups in the rate of pancreatic fistulas, morbidity, and mortality. However, a significantly lower wound infection rate was found in the RLPD group relative to the TLPD group (0% vs. 9.3%, P = 0.038). @*Conclusion@#RLPD showed the advantage of reducing the operation time compared to TLPD as well as technical feasibility and safety.

Effectiveness and stability of robot-assisted anastomosis in minimally invasive pancreaticoduodenectomy

Purpose@#Reconstruction using robotic assistance in pancreaticoduodenectomy (PD) was expected to be an effective means to overcome the limitations of laparoscopic surgery. To our knowledge, few comparative reports exist on the outcomes of totally laparoscopic PD (TLPD) and robot-assisted laparoscopic PD (RLPD). This retrospective study aimed to analyze the surgical results of TLPD and RLPD in a high-volume pancreatic center. @*Methods@#We analyzed the surgical results of consecutive patients who underwent a minimally invasive PD for malignant or benign periampullary lesions between January 2016 and May 2020. Forty-three TLPD patients and 49 RLPD patients were enrolled. @*Results@#There were no significant differences in the demographic characteristics between the 2 groups except for tumor size, which was significantly larger in the RLPD group than in the TLPD group (mean, 3.1 cm vs. 2.5 cm; P = 0.035).The RLPD group had shorter whole operative times (mean, 400.4 minutes vs. 352.2 minutes; P = 0.003) and shorter anastomosis times than the TLPD group (mean, 94.5 minutes vs. 54.9 minutes; P < 0.001). There was no significant difference between the 2 groups in the rate of pancreatic fistulas, morbidity, and mortality. However, a significantly lower wound infection rate was found in the RLPD group relative to the TLPD group (0% vs. 9.3%, P = 0.038). @*Conclusion@#RLPD showed the advantage of reducing the operation time compared to TLPD as well as technical feasibility and safety.

Feasibility Study of Synthetic Diffusion-Weighted MRIin Patients with Breast Cancer in Comparison withConventional Diffusion-Weighted MRI

Objective@#To investigate the clinical feasibility of synthetic diffusion-weighted imaging (sDWI) at different b-values in patientswith breast cancer by assessing the diagnostic image quality and the quantitative measurements compared with conventionaldiffusion-weighted imaging (cDWI). @*Materials and Methods@#Fifty patients with breast cancer were assessed using cDWI at b-values of 800 and 1500 s/mm2 (cDWI800and cDWI1500) and sDWI at b-values of 1000 and 1500 s/mm2 (sDWI1000 and sDWI1500). Qualitative analysis (normal glandulartissue suppression, overall image quality, and lesion conspicuity) was performed using a 4-point Likert-scale for all DWI setsand the cancer detection rate (CDR) was calculated. We also evaluated cancer-to-parenchyma contrast ratios for each DWI setin 45 patients with the lesion identified on any of the DWI sets. Statistical comparisons were performed using Friedman test,one-way analysis of variance, and Cochran’s Q test. @*Results@#All parameters of qualitative analysis, cancer-to-parenchyma contrast ratios, and CDR increased with increasingb-values, regardless of the type of imaging (synthetic or conventional) (p< 0.001). Additionally, sDWI1500 provided better lesionconspicuity than cDWI1500 (3.52 ± 0.92 vs. 3.39 ± 0.90, p< 0.05). Although cDWI1500 showed better normal glandular tissuesuppression and overall image quality than sDWI1500 (3.66 ± 0.78 and 3.73 ± 0.62 vs. 3.32 ± 0.90 and 3.35 ± 0.81, respectively;p< 0.05), there was no significant difference in their CDR (90.0%). Cancer-to-parenchyma contrast ratios were greater insDWI1500 than in cDWI1500 (0.63 ± 0.17 vs. 0.55 ± 0.18, p< 0.001). @*Conclusion@#sDWI1500 can be feasible for evaluating breast cancers in clinical practice. It provides higher tumor conspicuity,better cancer-to-parenchyma contrast ratio, and comparable CDR when compared with cDWI1500.

A Comprehensive Review of Percutaneous Nephrostomy and Suprapubic Cystostomy

Percutaneous nephrostomy is widely used for the diagnosis and treatment of various urinary tract diseases, such as ureteral fistula, stenosis, and percutaneous nephrolithotomy, and the relief of urinary obstruction. Suprapubic cystostomy is also known as a good method for bladder drainage in patients with lower urinary tract obstruction or injury and neurogenic bladder. Despite the frequent use of these procedures, reports in the literature are insufficient for an interventional radiologist to understand the procedures easily and thoroughly. In this article, the indication, anatomy, placement, and postoperative management of percutaneous nephrostomy and suprapubic cystostomy have been described, explaining that the procedures are safe and effective.

Surgical Management of Concurrent Strabismus and Face Turn in Patients with Infantile Nystagmus

PURPOSE: To investigate the effect of adjusted Kestenbaum surgery in patients with idiopathic infantile nystagmus who were affected by both strabismus and face turn. METHODS: This retrospective consecutive case series included 12 patients with infantile nystagmus who had face turn and strabismus. All patients underwent adjusted Kestenbaum surgery between 1996 and 2014, and primary outcome measures were the postoperative degree of face turn and strabismus. RESULTS: All patients had jerky nystagmus with compensatory face turn and strabismus. Of the 12 patients, eight patients were exotropes and four patients were esotropes. The mean age at surgery was 12.5 ± 10.7 years (range, 2–36 years). The mean postoperative follow-up was 17.8 ± 12.0 months (range, 7–43 months). Surgery was successful in eight (66.7%) out of 12 patients. Improvement of anomalous head posture was satisfactory in all patients, but an angle of deviation within 10 prism diopters was not achieved in four patients. CONCLUSIONS: Adjusted Kestenbaum surgery simultaneously improved both ocular misalignment and face turn with one-stage surgery. Two or three rectus muscles surgery can be considered in these patients because it is not only simpler than four muscles surgery but also can preserve one or two rectus muscles.

Functional Magnetic Resonance Imaging with Arterial Spin Labeling: Techniques and Potential Clinical and Research Applications

PURPOSE: To describe technical methods for functional magnetic resonance imaging (fMRI) study with arterial spin labeling (ASL) compared to blood oxygenation level-dependent (BOLD) technique and discuss the potential of ASL for research and clinical practice. MATERIALS AND METHODS: Task-based (n = 1) and resting-state fMRI (rs-fMRI) (n = 20) were performed using ASL and BOLD techniques. Results of both techniques were compared. RESULTS: For task-based fMRI with finger-tapping, the primary motor cortex of the contralateral frontal lobe and the ipsilateral cerebellum were activated by both BOLD and ASL fMRI. For rs-fMRI of sensorimotor network, functional connectivity showed similar results between BOLD and ASL. CONCLUSION: ASL technique has potential application in clinical and research fields because all brain perfusion imaging, CBF measurement, and rs-fMRI study can be performed in a single acquisition.

Functional Magnetic Resonance Imaging with Arterial Spin Labeling: Techniques and Potential Clinical and Research Applications

PURPOSE: To describe technical methods for functional magnetic resonance imaging (fMRI) study with arterial spin labeling (ASL) compared to blood oxygenation level-dependent (BOLD) technique and discuss the potential of ASL for research and clinical practice. MATERIALS AND METHODS: Task-based (n = 1) and resting-state fMRI (rs-fMRI) (n = 20) were performed using ASL and BOLD techniques. Results of both techniques were compared. RESULTS: For task-based fMRI with finger-tapping, the primary motor cortex of the contralateral frontal lobe and the ipsilateral cerebellum were activated by both BOLD and ASL fMRI. For rs-fMRI of sensorimotor network, functional connectivity showed similar results between BOLD and ASL. CONCLUSION: ASL technique has potential application in clinical and research fields because all brain perfusion imaging, CBF measurement, and rs-fMRI study can be performed in a single acquisition.

Skull Base Dermoid Cyst in the Right Infratemporal Fossa Diagnosed Using the Dixon Technique: a Case Report and Review of Literature

Dermoid cysts are benign congenital tumors composed of keratinizing squamous epithelium and dermal derivatives. They account for less than 1% of all intracranial tumors and are rarely exhibited at the base of the skull. To the best of our knowledge, only one case report has presented computed tomography and conventional T1-weighted magnetic resonance (MR) findings that revealed an infratemporal dermoid cyst. In the present study, we report an unusual case of a dermoid cyst in the right infratemporal fossa, which was incidentally detected by MR imaging with the Dixon technique. This article also highlights the importance of meticulous radiological review and the usefulness of the Dixon technique in everyday clinical practice.

Skull Base Dermoid Cyst in the Right Infratemporal Fossa Diagnosed Using the Dixon Technique: a Case Report and Review of Literature

Dermoid cysts are benign congenital tumors composed of keratinizing squamous epithelium and dermal derivatives. They account for less than 1% of all intracranial tumors and are rarely exhibited at the base of the skull. To the best of our knowledge, only one case report has presented computed tomography and conventional T1-weighted magnetic resonance (MR) findings that revealed an infratemporal dermoid cyst. In the present study, we report an unusual case of a dermoid cyst in the right infratemporal fossa, which was incidentally detected by MR imaging with the Dixon technique. This article also highlights the importance of meticulous radiological review and the usefulness of the Dixon technique in everyday clinical practice.

Splenial Lesions of the Corpus Callosum: Disease Spectrum and MRI Findings

The corpus callosum (CC) is the largest white matter structure in the brain, consisting of more than 200–250 million axons that provide a large connection mainly between homologous cerebral cortical areas in mirror image sites. The posterior end of the CC is the thickest part, which is called the splenium. Various diseases including congenital to acquired lesions including congenital anomalies, traumatic lesions, ischemic diseases, tumors, metabolic, toxic, degenerative, and demyelinating diseases, can involve the splenium of the CC and their clinical symptoms and signs are also variable. Therefore, knowledge of the disease entities and the imaging findings of lesions involving the splenium is valuable in clinical practice. MR imaging is useful for the detection and differential diagnosis of splenial lesions of the CC. In this study, we classify the disease entities and describe imaging findings of lesions involving the splenium of the CC based on our experiences and a review of the literature.

Pharmacokinetics of atorvastatin and sustained-release metformin fixed-dose combination tablets: two randomized, open-label, 2-way crossover studies in healthy male subjects under fed conditions

Two separate studies were conducted to establish bioequivalence (BE) for two doses of atorvastatin/metformin sustained-release (SR) fixed dose combination (FDC) versus the same dosage of the individual component (IC) tablets in healthy male subjects under fed conditions (study 1, BE of atorvastatin/metformin SR 20/500 mg FDC; study 2, BE of atorvastatin/metformin SR 20/750 mg FDC). Each study was a randomized, open-label, single oral dose, two-way crossover design. Serial blood samples were collected pre-dose and up to 36 hours post-dose for atorvastatin and 24 hours for metformin. Plasma concentrations of atorvastatin, 2-OH atorvastatin and metformin were analyzed using a validated liquid chromatography tandem mass-spectrometry. A non-compartmental analysis was used to calculate pharmacokinetic (PK) variables and analysis of variance was performed on the lognormal-transformed PK variables. A total of 75 subjects completed the study 1 (36 subjects) and study 2 (39 subjects). The 90% confidence intervals for the adjusted geometric mean ratio of Cmax and the AUC0-t were within the predefined 0.80 to 1.25 range. The number of subjects reporting at least one adverse event following FDC treatments was comparable to that following IC treatments. The two treatments were well tolerated. Therefore, atorvastatin/metformin SR 20/500 mg and 20/750 mg FDC tablets are expected to be used as alternatives to IC tablets to decrease the pill burden and increase patient compliance.

An Aggressive Natural Killer Cell Lymphoma Presenting as Acute Liver Failure with Ascites / 대한내과학회지

Acute liver failure (ALF) is a medical emergency triggering an urgent need for liver transplantation. The most common causes of ALF are drug- and virus-associated hepatitis, but hematological malignancies such as an aggressive natural killer cell lymphoma (ANKL) can uncommonly cause ALF. A 50 year-old male presented with ascites, jaundice, and encephalopathy. The ascitic fluid had a serum-ascites albumin gradient of 0.3 g/L, and contained atypical lymphocytes, which were positive for CD3. Computed tomography revealed mild hepatomegaly and multiple nodules in both lobes of the liver. A liver biopsy showed that the liver parenchyma had been infiltrated by malignant lymphoid cells, and exhibited marked sinusoidal dilatation. Immunohistochemically, the lymphoid cells were positive for CD3, CD56, and Epstein-Barr virus-encoded small RNA. The patient was diagnosed with ANKL causing ALF, and died on hospital day 12. This case shows that infiltration of the liver with ANKL can (rarely) cause ALF.

Susceptibility Vessel Sign for the Detection of Hyperacute MCA Occlusion: Evaluation with Susceptibility-weighted MR Imaging

PURPOSE: Susceptibility vessel sign (SVS) on gradient echo image, which is caused by MR signal loss due to arterial thrombosis, has been reported in acute middle cerebral artery (MCA) infarction. However, the reported sensitivity and diagnostic accuracy of SVS have been variable. Susceptibility-weighted imaging (SWI) is a newly developed MR sequence. Recent studies have found that SWI may be useful in the field of cerebrovascular diseases, especially for detecting the presence of prominent veins, microbleeds and the SVS. The purpose of this study was to evaluate the diagnostic values of SWI for the detection of hyperacute MCA occlusion. MATERIALS AND METHODS: Sixty-nine patients (37 males, 32 females; 46-89 years old [mean, 69.1]) with acute stroke involving the MCA territory underwent MR imaging within 6 hours after the symptom onset. MR examination included T2, FLAIR (fluid-attenuated inversion recovery), DWI, SWI, PWI (perfusion-weighted imaging), contrast-enhanced MR angiography (MRA) and contrast-enhanced T1. Of these patients, 28 patients also underwent digital subtraction angiography (DSA) within 2 hours after MR examination. Presence or absence of SVS on SWI was assessed without knowledge of clinical, DSA and other MR imaging findings. RESULTS: On MRA or DSA, 34 patients (49.3%) showed MCA occlusion. Of these patients, SVS was detected in 30 (88.2%) on SWI. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of SWI were 88.2%, 97.1%, 96.8%, 89.5% and 92.8%, respectively. CONCLUSION: SWI was sensitive, specific and accurate for the detection of hyperacute MCA occlusion.

The Effect of Inferior Oblique Muscle Transposition in Primary and Secondary Inferior Oblique Muscle Overaction

PURPOSE: To evaluate and compare the effect of transposition of inferior oblique muscle in patients with primary inferior oblique muscle overaction and secondary due to superior oblique muscle palsy. METHODS: The present study included 41 patients (53 eyes), who appeared to have primary or secondary inferior oblique muscle overaction due to superior oblique muscle palsy and received transposition of inferior oblique muscle with at least 3 months of follow-up. Patients were retrospectively analyzed to compare the effect of correction and its prognosis. Inferior oblique muscle overaction was graded as +1 to +4 according to the severity. Successful surgery was defined as postoperative inferior oblique muscle overaction from 0 to +1 and failure as above +2. Hypertropia in primary gaze was also recorded to evaluate the effect of correction. RESULTS: Twenty-six (35 eyes) and 15 (18 eyes) patients with primary and secondary inferior oblique muscle overaction due to superior oblique muscle palsy, respectively, received transposition of inferior oblique muscle. Patients with primary inferior oblique muscle overaction showed correction of 2.1 +/- 0.9 with preoperative inferior oblique muscle overaction of 2.0 +/- 0.7. Patients with secondary inferior oblique muscle overaction showed a correction of 2.3 +/- 0.9 with preoperative value of 2.3 +/- 0.8. Each 3.2 +/- 4.1 prism diopters (PD) and 6.5 +/- 5.3 PD of hypertropia at primary gaze showed correction of 3.0 +/- 7.4 PD and 6.3 +/- 5.1 PD, respectively, in each group. CONCLUSIONS: Primary and secondary inferior oblique muscle overaction due to superior oblique muscle palsy showed no difference in correction of overaction and hypertropia after transposition of inferior oblique muscle. Except for presence of inferior oblique muscle underaction, the correction appears effective with good prognosis.

An 8-month-old Male Infant with High Grade Vesicoureteral Reflux who Developed Incomplete Kawasaki disease after Recurrent Pyelonephritis

Kawasaki disease (KD) is a systemic vasculitis that can affect many organ systems. Renal manifestations include pyuria, hematuria, proteinuria, tubulointerstitial nephritis, acute renal failure, hemolytic uremic syndrome, or renal scarring. Although its precise pathogenesis remains unknown, it is considered an autoimmune disease. In the literature, it has been reported that KD may develop in conjunction with urinary tract infections. However, many of these previous studies did not use imaging methods such as renal sonograms, dimercaptosuccinic acid renal scans, and voiding urethrocystograms. We report a case of an 8-month old male infant with high grade vesicoureteral reflux, who developed incomplete KD after recurrent pyelonephritis. Acute pyelonephritis can be an early manifestation of KD. Such cases require the evaluation of urinary tract anomalies according to the guidelines for the management of urinary tract infections.

A Case of Severe Influenza Infection in a Child with Nephrotic Syndrome on Steroid Therapy

Infection is the most important cause of death in children with nephrotic syndrome. Influenza viral infections can be fatal for these children, given the annual outbreak of this virus, with the mortality rate being similar to that of respiratory syncytial virus in healthy children. Pneumonia is recognized as the most important complication of influenza infections, as it is associated with high death rates. However, the influenza vaccine, as well as antiviral agents, can be used for prevention and treatment. Therefore, aggressive management with influenza vaccination and antiviral agents will lower the overall mortality rate in children with nephrotic syndrome. Here we report the case of a 7-year-old boy with nephrotic syndrome and influenza A virus (H1N1) pneumonia.

Hemorrhagic Bullous Lesions in a 9-year-old Girl with Henoch-Scholein Purpura

Henoch-Schonlein purpura (HSP) is the most common vasculitis in children and is characterized by cutaneous purpura, arthritis, abdominal pain, and nephritis. Bullous skin lesions are rare in children. We report a case involving a 9-year-old female with HSP who displayed rapidly evolving hemorrhagic bullae from the primary purpuric lesions during systemic corticosteroid therapy. The bullae disappeared within 7 days of systemic corticosteroid therapy. Some scar lesions of the skin developed on acute phase recovered completely after 6 months. Bullae should not be considered as a poor prognostic factor of HSP and its renal outcome. Skin biopsy in HSP children with bullae is not necessary if clinical diagnostic criteria of HSP are met. However, further evaluation of more pediatric HSP with bullae is needed to get the clearer conclusions. We report a 9-year-old female with HSP who showed the rapidly evolving hemorrhagic bullae from primary purpuric lesions during systemic corticosteroid therapy.

Transient Pseudohypoaldosteronism in an Infant with Vesicoureteral Reflux

A 6-month-old boy with vesicoureteral reflux exhibited features of transient type 1 pseudohypoaldosteronism (PHA) in the course of urinary tract infection. PHA presents hyponatremia, hyperkalemia, and metabolic acidosis, accompanying with high urinary sodium, low potassium excretion, and high plasma aldosterone concentration. Severe electrolyte disturbance can occur in an infant with vesicoureteral reflux because of secondary PHA. Appropriate treatment of dehydration and sodium supplementation induces rapid improvement of electrolyte imbalance and metabolic acidosis resulting from secondary PHA associated with vesicoureteral reflux.