Visual field loss with colored hydrogel lenses

The visual fields of 10 healthy myopic patients were compared using hydrogel lenses with a clear pupil and an opaque colored portion covering the iris and clear hydrogel lenses. Significant (greater than 10 degrees) field loss was found in all cases when the midperipherally colored lenses were worn. Patients interested in these lenses should be advised of this slight reduction of peripheral vision before fitting.     

Sonic hedgehog promotes desmoplasia in pancreatic cancer

PURPOSE: We investigated the contribution of Sonic hedgehog (SHH) to pancreatic cancer progression. EXPERIMENTAL DESIGN: We expressed SHH in a transformed primary ductal-derived epithelial cell line from the human pancreas, transformed hTert-HPNE (T-HPNE), and evaluated the effects on tumor growth. We also directly inhibited the activity of SHH in vivo by administering a blocking antibody to mice challenged orthotopically with the Capan-2 pancreatic cancer cell line, which is known to express SHH and form moderately differentiated tumors in nude mice. RESULTS: Our data provide evidence that expression of SHH influences tumor growth by contributing to the formation of desmoplasia in pancreatic cancer. We further show that SHH affects the differentiation and motility of human pancreatic stellate cells and fibroblasts. CONCLUSIONS: These data suggest that SHH contributes to the formation of desmoplasia in pancreatic cancer, an important component of the tumor microenvironment.     

Radiological interpretation of images displayed on tablet computers: a systematic review

Objective:

To review the published evidence and to determine if radiological diagnostic accuracy is compromised when images are displayed on a tablet computer and thereby inform practice on using tablet computers for radiological interpretation by on-call radiologists.

Methods:

We searched the PubMed and EMBASE databases for studies on the diagnostic accuracy or diagnostic reliability of images interpreted on tablet computers. Studies were screened for inclusion based on pre-determined inclusion and exclusion criteria. Studies were assessed for quality and risk of bias using Quality Appraisal of Diagnostic Reliability Studies or the revised Quality Assessment of Diagnostic Accuracy Studies tool. Treatment of studies was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

Results:

11 studies met the inclusion criteria. 10 of these studies tested the Apple iPad^® (Apple, Cupertino, CA). The included studies reported high sensitivity (84–98%), specificity (74–100%) and accuracy rates (98–100%) for radiological diagnosis. There was no statistically significant difference in accuracy between a tablet computer and a digital imaging and communication in medicine-calibrated control display. There was a near complete consensus from authors on the non-inferiority of diagnostic accuracy of images displayed on a tablet computer. All of the included studies were judged to be at risk of bias.

Conclusion:

Our findings suggest that the diagnostic accuracy of radiological interpretation is not compromised by using a tablet computer. This result is only relevant to the Apple iPad and to the modalities of CT, MRI and plain radiography.

Advances in knowledge:

The iPad may be appropriate for an on-call radiologist to use for radiological interpretation.Consumer tablet computers can be used to access and display digital radiographic images for the purpose of radiological interpretation. Because tablet computers are portable, they have a potential role in remote, emergency diagnostic radiology services. There has been limited acceptance of smartphones for radiological interpretation because of their small screen size and limited display resolution.¹ Tablet computers offer similar portability to a smartphone but with high-resolution displays and a larger viewing size.² Hence, a tablet computer may be a more suitable display device for on-call radiologists.The luminance and contrast properties of computer displays can vary considerably causing inconsistent display of images between devices. The accepted process for achieving consistent display of medical images is by calibration of the display device to the digital imaging and communication in medicine (DICOM) greyscale display function (GSDF).³ Conformance to the GSDF has been shown to improve diagnostic accuracy.^4,5 A primary display is a dedicated medical display device and is used by radiologists for primary diagnosis. Whereas, a secondary display is often a commercial-off-the-shelf computer display. Established guidelines recommend conformance to the GSDF should be better than 10% and 20% for primary and secondary displays, respectively.⁶ Whilst both primary and secondary liquid crystal display (LCD) devices can be calibrated to the GSDF, it is not possible to calibrate a tablet computer, which may potentially compromise accuracy.⁷ Despite the inability to calibrate the display, high levels of diagnostic accuracy have been reported when using tablet computers.^8–10 Hence, there is contradictory information to inform practice on the use of tablet computers for radiological interpretation.To date, there has been no attempt to synthesize the existing research evidence pertaining to diagnostic accuracy or diagnostic reliability of using tablet computers for radiological interpretation. The aim of this study was to systematically review the published literature to determine if diagnostic accuracy is compromised when images are displayed on a tablet computer, which would in turn inform practice on the appropriateness of an on-call radiologist using a tablet computer for radiological interpretation.     

Evaluation of 3D guided electroanatomic mapping for ablation of atrial fibrillation in reference to CT-Scan image integration

Background  Anatomical guided atrial fibrillation (AF) catheter ablation relies on the assumption that the left atrium reconstruction anatomy (LARA) using a 3D mapping system precisely matches the patient’s CT scan anatomy (real anatomy). This study investigates whether this postulation is accurate using CT scan image integration. Patients and methods  Thirty consecutive patients (23 men, mean age = 51.9 ± 9.9 years) with symptomatic drug-refractory paroxysmal (n = 21) or persistent (n = 9) AF underwent a circumferential, 2 × 2, pulmonary vein (PV) radiofrequency (RF) ablation using the CARTOMERGE system. Left atrium (LA) anatomy was first reconstructed and RF design lines drawn on this LARA. After a CT-scan image of the LA was integrated into the 3D system, RF lesions were deployed 10 ± 5 mm outside the PV ostia (PVO) onto the CT-scan LA surface. The match between the actual RF lines and the RF design lines was analyzed off-line after catheter withdrawal. Results  Circumferential RF design lines were divided into four segments encircling both the right and left PVs. Design segments matched the actual RF segments in a proportion varying from 23% up to 83%. A mean of 2.8 ± 1.6 segments per patient were inaccurately designed that extended a mean of 3.8 ± 2.3mm inside the adjacent PV or 6.7 ± 1.8mm inside the left atrial appendage (LAA). Seven patients (23%) had four or more segments incorrectly designed. Conclusions  Our study reveals the inaccuracy of 3D anatomic guided RF ablation with respect to the LA anatomical structures that could be possibly improved when combined with CT-scan image integration.