Investigation and management of hepatic incidentalomas.

With the widespread use of medical imaging has come the detection of incidental liver lesions that are, by and large, asymptomatic prior to their discovery. These lesions may become a source of anxiety and often require further investigation to reassure the patient of their usually benign nature. Use of contemporary hepatobiliary imaging and simple laboratory tests often allow a definite diagnosis to be made without resorting to exhaustive investigation or inappropriate surgery. The goal of this paper is to review the clinical features and imaging characteristics of common and important liver incidentalomas, their natural course, complications, and indications for surgical or other intervention.

Low-grade appendiceal mucinous neoplasm (LAMN) as a mimicker of perforated diverticulitis: a case report.

The differential diagnosis of abdominal pain is wide as both benign and malignant pathologies must be considered. There are currently no published case reports of low-grade appendiceal mucinous neoplasms (LAMNs) mimicking perforated diverticulitis. LAMNs are a heterogenous group of tumours, with no consensus treatment algorithm based on stage and histology. In this case report, we discuss a patient who presented emergently with generalized peritonism, with a diagnosis of perforated diverticulitis made on computed tomography scan. At laparotomy, a perforated appendix was identified, with histopathology identifying a perforated LAMN. This case highlights the importance of considering this rare but increasing incidence tumour when operative management is being planned.

Functional Imaging of the Outer Retinal Complex using High Fidelity Imaging Retinal Densitometry.

We describe a new technique, high fidelity Imaging Retinal Densitometry (IRD), which probes the functional integrity of the outer retinal complex. We demonstrate the ability of the technique to map visual pigment optical density and synthesis rates in eyes with and without macular disease. A multispectral retinal imaging device obtained precise measurements of retinal reflectance over space and time. Data obtained from healthy controls and 5 patients with intermediate AMD, before and after photopigment bleaching, were used to quantify visual pigment metrics. Heat maps were plotted to summarise the topography of rod and cone pigment kinetics and descriptive statistics conducted to highlight differences between those with and without AMD. Rod and cone visual pigment synthesis rates in those with AMD (v = 0.043 SD 0.019 min-1 and v = 0.119 SD 0.046 min-1, respectively) were approximately half those observed in healthy controls (v = 0.079 SD 0.024 min-1 for rods and v = 0.206 SD 0.069 min-1 for cones). By mapping visual pigment kinetics across the central retina, high fidelity IRD provides a unique insight into outer retinal complex function. This new technique will improve the phenotypic characterisation, diagnosis and treatment monitoring of various ocular pathologies, including AMD.

Minimally invasive McKeown's vs open oesophagectomy for cancer: A meta-analysis.

BACKGROUND: The effectiveness of minimally invasive oesophagectomy (MIO) compared to open oesophagectomy (OO) remains controversial. Various techniques for performing MIO are currently used, but the evidence for them is lacking. The objective of this meta-analysis was to compare the safety, efficacy and oncological outcomes of McKeown's minimally invasive oesophagectomy (McKeown's-MIO) to OO. METHODS: PubMed, Embase and Cochrane Library databases were searched up to December 2016 for relevant articles comparing McKeown's-MIO to OO. As no randomised control trials (RCTs) currently exist, only cohort and case control studies were included. Fixed or random-effects models were used to calculate summary odds ratios (ORs) or relative risks (RRs) for binary outcomes, and hazard ratios (HRs) for time-to-event outcomes. Heterogeneity among studies were evaluated using I2 statistics. RESULTS: Four studies, which consisted a total of 573 patients, were included in the meta-analysis. In comparison to patients undergoing OO, those who were treated with McKeown's-MIO had a reduced incidence of pneumonia and total respiratory complications, however, there were no statistically significant differences for other measures of safety such as RLN palsy and anastomotic leak. In terms of efficacy data, MIO had significantly less blood loss and a shorter duration of hospital stay but a longer operating time. Lymph node retrieval trended towards favouring McKeown's-MIO, but was not statistically significant. There was insufficient data to report on other oncological outcomes. CONCLUSIONS: McKeown's-MIO is a safe and effective procedure that has comparable outcomes to OO. However, RCTs with large sample sizes are needed to confirm these results.

Optophysiological Characterisation of Inner Retina Responses with High-Resolution Optical Coherence Tomography.

Low coherence laser interferometry has revolutionised quantitative biomedical imaging of optically transparent structures at cellular resolutions. We report the first optical recording of neuronal excitation at cellular resolution in the inner retina by quantifying optically recorded stimulus-evoked responses from the retinal ganglion cell layer and comparing them with an electrophysiological standard. We imaged anaesthetised paralysed tree shrews, gated image acquisition, and used numerical filters to eliminate noise arising from retinal movements during respiratory and cardiac cycles. We observed increases in contrast variability in the retinal ganglion cell layer and nerve fibre layer with flash stimuli and gratings. Regions of interest were subdivided into three-dimensional patches (up to 5-15 µm in diameter) based on response similarity. We hypothesise that these patches correspond to individual cells, or segments of blood vessels within the inner retina. We observed a close correlation between the patch optical responses and mean electrical activity of the visual neurons in afferent pathway. While our data suggest that optical imaging of retinal activity is possible with high resolution OCT, the technical challenges are not trivial.

The Structural Role of Elastic Fibers in the Cornea Investigated Using a Mouse Model for Marfan Syndrome.

Purpose: The presence of fibrillin-rich elastic fibers in the cornea has been overlooked in recent years. The aim of the current study was to elucidate their functional role using a mouse model for Marfan syndrome, defective in fibrillin-1, the major structural component of the microfibril bundles that constitute most of the elastic fibers. Methods: Mouse corneas were obtained from animals with a heterozygous fibrillin-1 mutation (Fbn1+/-) and compared to wild type controls. Corneal thickness and radius of curvature were calculated using optical coherence tomography microscopy. Elastic microfibril bundles were quantified and visualized in three-dimensions using serial block face scanning electron microscopy. Transmission electron microscopy was used to analyze stromal ultrastructure and proteoglycan distribution. Center-to-center average interfibrillar spacing was determined using x-ray scattering. Results: Fbn1+/- corneas were significantly thinner than wild types and displayed a higher radius of curvature. In the Fbn1+/- corneas, elastic microfibril bundles were significantly reduced in density and disorganized compared to wild-type controls, in addition to containing a higher average center-to-center collagen interfibrillar spacing in the center of the cornea. No other differences were detected in stromal ultrastructure or proteoglycan distribution between the two groups. Proteoglycan side chains appeared to colocalize with the microfibril bundles. Conclusions: Elastic fibers have an important, multifunctional role in the cornea as highlighted by the differences observed between Fbn1+/- and wild type animals. We contend that the presence of normal quantities of structurally organized elastic fibers are required to maintain the correct geometry of the cornea, which is disrupted in Marfan syndrome.

Automated Retinal Layer Segmentation Using Spectral Domain Optical Coherence Tomography: Evaluation of Inter-Session Repeatability and Agreement between Devices.

Retinal and intra-retinal layer thicknesses are routinely generated from optical coherence tomography (OCT) images, but on-board software capabilities and image scaling assumptions are not consistent across devices. This study evaluates the device-independent Iowa Reference Algorithms (Iowa Institute for Biomedical Imaging) for automated intra-retinal layer segmentation and image scaling for three OCT systems. Healthy participants (n = 25) underwent macular volume scans using a Cirrus HD-OCT (Zeiss), 3D-OCT 1000 (Topcon), and a non-commercial long-wavelength (1040nm) OCT on two occasions. Mean thickness of 10 intra-retinal layers was measured in three ETDRS subfields (fovea, inner ring and outer ring) using the Iowa Reference Algorithms. Where available, total retinal thicknesses were measured using on-board software. Measured axial eye length (AEL)-dependent scaling was used throughout, with a comparison made to the system-specific fixed-AEL scaling. Inter-session repeatability and agreement between OCT systems and segmentation methods was assessed. Inter-session coefficient of repeatability (CoR) for the foveal subfield total retinal thickness was 3.43µm, 4.76µm, and 5.98µm for the Zeiss, Topcon, and long-wavelength images respectively. For the commercial software, CoR was 4.63µm (Zeiss) and 7.63µm (Topcon). The Iowa Reference Algorithms demonstrated higher repeatability than the on-board software and, in addition, reliably segmented all 10 intra-retinal layers. With fixed-AEL scaling, the algorithm produced significantly different thickness values for the three OCT devices (P<0.05), with these discrepancies generally characterized by an overall offset (bias) and correlations with axial eye length for the foveal subfield and outer ring (P<0.05). This correlation was reduced to an insignificant level in all cases when AEL-dependent scaling was used. Overall, the Iowa Reference Algorithms are viable for clinical and research use in healthy eyes imaged with these devices, however ocular biometry is required for accurate quantification of OCT images.

Utility of white cell count and ultrasound in the diagnosis of acute appendicitis.

BACKGROUND: Despite considerable advances in imaging, the diagnosis of acute appendicitis remains a clinical one. Nonetheless, knowledge of the characteristics of commonly used investigations for appendicitis may aid surgical decision-making. METHODS: The pathology, full blood counts and ultrasounds of 1013 patients who underwent appendicectomy were reviewed and subjected to statistical analysis in order to determine diagnostic characteristics of various white cell count and ultrasound results. RESULTS: Total white cell count was found to be higher among patients with complicated appendicitis than those with simple appendicitis or normal appendices. Ultrasound was found to be less accurate than white cell count and neutrophil count in the diagnosis of acute appendicitis by estimation of area under the receiver operator characteristic curve. CONCLUSION: Knowledge of the meaning of various white cell count values may be invaluable in clinical decision-making with regard to the diagnosis of acute appendicitis. Ultrasound is of limited utility in the diagnosis of appendicitis and should only be used in selected clinical situations.

Small bowel obstruction in the virgin abdomen: the need for a mandatory laparotomy explored.

BACKGROUND: A laparotomy is still considered mandatory for patients without previous abdominal surgery presenting with a small bowel obstruction (SBO) because of a perceived high incidence of underlying lesions. However, there is no evidence in literature to support this assumption. We analyzed the etiology of SBO in this subgroup of patients to establish the need for a mandatory laparotomy. METHODS: A retrospective analysis was conducted over a 5-year period. Basic demographics, radiology results, operative findings, and outpatient investigations were analyzed. RESULTS: Of 689 patients presenting with an SBO, a total of 62 patients, 9.0%, had a virgin abdomen. A known underlying disease (inflammatory bowel disease, malignancy) was the cause in 13 patients. The remaining 49 patients had adhesions in 75.5% and a newly diagnosed malignancy in 10.2% as a cause. CONCLUSIONS: Adhesions are by far the most likely cause of SBO in patients without previous abdominal surgery followed by a small number of newly diagnosed malignancies. Both prevalences are in equal proportion to patients with previous abdominal surgery. A trial of nonoperative management may therefore be justified.