Assessment of tumor blood flow distribution by dynamic contrast-enhanced CT.

A distinct feature of the tumor vasculature is its tortuosity and irregular branching of vessels, which can translate to a wider dispersion and higher variability of blood flow in the tumor. To enable tumor blood flow variability to be assessed in vivo by imaging, a tracer kinetic model that accounts for flow dispersion is developed for use with dynamic contrast-enhanced (DCE) CT. The proposed model adopts a multiple-pathway approach and allows for the quantification of relative dispersion in the blood flow distribution, which reflects flow variability in the tumor vasculature. Monte Carlo simulation experiments were performed to study the possibility of reducing the number of model parameters based on the Akaike information criterion approach and to explore possible noise and tissue conditions in which the model might be applicable. The model was used for region-of-interest analysis and to generate perfusion parameter maps for three patient DCE CT cases with cerebral tumors, to illustrate clinical applicability.

Automated identification of diabetes type-2 subjects with and without neuropathy using eigenvalues.

Diabetes is a disorder of metabolism and has been a leading healthcare burden throughout the world. The most typical form of diabetes is type-2 diabetes. It is commonly developed in adults of age 40 and older. The purpose of this study is to identify the plantar pressure distribution in normal subjects, diabetic type-2 subjects with neuropathy, and diabetic type-2 subjects without neuropathy. Foot scan images were obtained using the F-Scan (Tekscan USA) in-shoe measurement system. The eigenvalues were evaluated from principal-component analysis after performing continuous wavelets transformation (CWT). The eigenvalues of CWT in regions 5 and 7 had shown excellent p values of more than 95 per cent confidence level when subjected to an analysis-of-variance test. These parameters were then presented to an artificial neural network (ANN) and a Gaussian mixture model (GMM) for automatic classification. The results show that the ANN classifier performs better than the GMM and is able to identify the unknown class with a sensitivity of 100 per cent and a specificity of 72 per cent.

Persistent left superior vena cava: a possible site for haemodialysis catheter placement.

Persistent left superior vena cava (PLSVC) is a congenital variant of the thoracic venous system, which is associated with other congenital abnormalities. Asymptomatic cases are often diagnosed incidentally during invasive cardiovascular procedures such as the deployment of central venous access devices. It is important to be aware of the existence of a PLSVC and the clinical implications that it may pose to the proceduralist during catheter placement. We describe our experience and the lessons learnt during the placement of a haemodialysis catheter via the left internal jugular venous route in a patient with unsuspected PLSVC.

Influence of visual feedback and speed on micromanipulation accuracy.

Accuracy in micromanipulation tasks is limited and it is important to identify various factors affecting it. This paper studies the effect of visual magnification, speed and handedness to micromanipulation accuracy using microscope and LCD screen for feedback. Magnification of visual feedback increases the accuracy, but large magnification does not provide further improvement beyond 16x. Further, we observed a trade off between speed and accuracy in tracing a circular path, i.e. faster speed reduces the speed control ability of the hand. Finally, dominant/non-dominant hand is found to affect accuracy in motion.

Non-linear analysis of body responses to functional electrical stimulation on hemiplegic subjects.

Functional electrical stimulation (FES) is a method of applying low-level electrical currents to restore or improve body functions lost through nervous system impairment. FES is applied to peripheral nerves that control specific muscles or muscle groups. Application of advanced signal computing techniques to the medical field has helped to achieve practical solutions to the health care problems accurately. The physiological signals are essentially non-stationary and may contain indicators of current disease, or even warnings about impending diseases. These indicators may be present at all times or may occur at random on the timescale. However, to study and pinpoint these subtle changes in the voluminous data collected over several hours is tedious. These signals, e.g. walking-related accelerometer signals, are not simply linear and involve non-linear contributions. Hence, non-linear signal-processing methods may be useful to extract the hidden complexities of the signal and to aid physicians in their diagnosis. In this work, a young female subject with major neuromuscular dysfunction of the left lower limb, which resulted in an asymmetric hemiplegic gait, participated in a series of FES-assisted walking experiments. Two three-axis accelerometers were attached to her left and right ankles and their corresponding signals were recorded during FES-assisted walking. The accelerometer signals were studied in three directions using the Hurst exponent H, the fractal dimension (FD), the phase space plot, and recurrence plots (RPs). The results showed that the H and FD values increase with increasing FES, indicating more synchronized variability due to FES for the left leg (paralysed leg). However, the variation in the normal right leg is more chaotic on FES.

Clinics in diagnostic imaging (120). Right rhinogenic optic neuritis secondary to mucocoele of the Onodi cell.

Acute visual loss can be caused by retrobulbar optic neuritis, radiation optic neuropathy or ischaemic optic neuropathy. Sinusitis affecting the Onodi cell, a posterior ethmoidal air cell that has encroached on the adjacent sphenoid bone forming the optic canal, can present rarely with visual loss. We report a 60-year-old man, who developed a sudden ache on the nasal aspect of his right eye, and deterioration of the vision in his right eye. This case illustrates the typical radiological appearances of the Onodi cell on MR imaging and CT. The diagnosis of right rhinogenic optic neuritis secondary to mucocoele of the Onodi cell was confirmed at surgery. Functional endoscopic sinus surgery with decompression of the Onodi cell was performed. Physicians should be familiar with the presentation, performed. Physicians should be familiar with the presentation, diagnosis and management of this rare but important condition.

Oxygen discharge and post-discharge kinetics experiments and modeling for the electric oxygen-iodine laser system.

Laser oscillation at 1315 nm on the I(2P1/2)-->I(2P3/2) transition of atomic iodine has been obtained by a near resonant energy transfer from O2(a1Delta) produced using a low-pressure oxygen/helium/nitric oxide discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited species adds levels of complexity to the singlet oxygen generator (SOG) kinetics which are not encountered in a classic purely chemical O2(a1Delta) generation system. The advanced model BLAZE-IV has been introduced to study the energy-transfer laser system dynamics and kinetics. Levels of singlet oxygen, oxygen atoms, and ozone are measured experimentally and compared with calculations. The new BLAZE-IV model is in reasonable agreement with O3, O atom, and gas temperature measurements but is under-predicting the increase in O2(a1Delta) concentration resulting from the presence of NO in the discharge and under-predicting the O2(b1Sigma) concentrations. A key conclusion is that the removal of oxygen atoms by NOX species leads to a significant increase in O2(a1Delta) concentrations downstream of the discharge in part via a recycling process; however, there are still some important processes related to the NOX discharge kinetics that are missing from the present modeling. Further, the removal of oxygen atoms dramatically inhibits the production of ozone in the downstream kinetics.

Creation of an intermammary sulcus in congenital synmastia.

Synmastia is a condition where both breasts appear conjoint without an intervening intermammary sulcus. This is usually the result of technical complications during breast implant surgery caused by over-dissection of the medial pocket over the sternum in the subglandular plane, or by an over-division of the pectoralis muscle origin along the sternum in a submuscular plane. As a congenital problem, this is very rare with only a single previous report of an attempt to correct this anomaly. We report a rare case of synmastia in a 19-year-old Indian woman. She had no previous surgery or family history of the condition. Vertical-scar reduction mammoplasty was performed for the hypertrophic breasts. Using the same access, the synmastia was corrected. This approach avoided incisions on the sternum, which is one of the keloid-prone sites on the body. Eight months postoperation, the intermammary sulcus was maintained.

A comparative analysis of scaffold material modifications for load-bearing applications in bone tissue engineering.

To facilitate optimal application of appropriate scaffold architectures for clinical trials, there is a need to compare different scaffold modifications under similar experimental conditions. In this study was assessed the effectiveness of poly-e-caprolactone (PCL) scaffolds fabricated by fused deposition modelling (FDM), with varying material modifications, for the purposes of bone tissue engineering. The incorporation of hydroxyapatite (HA) in PCL scaffolds, as well as precalcification through immersion in a simulated body fluid (SBF) to produce a biomimetic apatite coating on the scaffolds, was assessed. A series of in vitro studies spanning 3 weeks as well as in vivo studies utilizing a subcutaneous nude mouse model were carried out. PCL and HA-PCL scaffolds demonstrated increasing tissue growth extending throughout the implants, as well as superior mechanical strength and mineralization, as evidenced by X-ray imaging after 14 weeks in vivo. No significant difference was found between PCL and HA-PCL scaffolds. Precalcification with SBF did not result in increased osteoconductivity and cell proliferation as previously reported. Conversely, tensile forces exerted by tissue sheets bridging adjacent struts of the PCL scaffold caused flaking of the apatite coating that resulted in impaired cell attachment, growth and mineralization. The results suggest that scaffolds fabricated by FDM may have load-bearing applications.

A case of ductal carcinoma in situ of breast with Poland syndrome.

INTRODUCTION: A 51-year-old woman was diagnosed with a rare case of multi-focal ductal carcinoma in situ (DCIS) of the breast associated with Poland syndrome. CLINICAL PICTURE: Physical examination showed mild hypoplasia of the left breast with microcalcifications on mammogram. Intraoperatively, there was complete absence of the pectoralis major, which precluded the insertion of a breast implant. TREATMENT AND OUTCOME: She underwent a skin-sparing mastectomy and autologous microsurgical free flap reconstruction with deep inferior epigastric perforator (DIEP) flap. Postoperative recovery was uneventful with no evidence of recurrence at 6 months. CONCLUSION: This is the first reported case of DCIS of the breast with Poland syndrome. We performed a skin-sparing mastectomy with immediate DIEP flap recontruction. Patient recovered well postoperatively with no evidence of recurrence at 6 months.

Changes in the local morphology of the rectus abdominis muscle following the DIEP flap: an ultrasonographic study.

This study was undertaken to assess the changes in the local morphology of the rectus abdominis muscle following intramuscular dissection of the deep inferior epigastric artery perforators after harvesting of the deep inferior epigastric perforator (DIEP) flap. While the DIEP provides the well-known advantage of use of the lower abdominal tissue with preservation of the integrity of the abdominal wall musculature, postoperative problems such as abdominal asymmetry, bulges and reduced flexion capacity have been found. These changes may be due to rectus abdominis muscle damage from ischemia or denervation. We used ultrasonography to assess the changes in rectus abdominis muscle thickness and contractility, preoperatively, 1-month and 1-year postoperatively. The study group consisted of 17 rectus abdominis muscles in 14 patients subjected to intramuscular dissection of perforators. The control group consisted of 11 intact rectus abdominis muscles in 11 patients who had undergone unilateral DIEP flap elevation, the dissected muscles being part of the study group. We found that the resting muscle thickness in the study group was, significantly increased at 1-month postoperatively, resolving by 1-year follow-up. As these changes were not seen in the control group, the increased muscle thickness is attributed to postoperative oedema that resolves with time. All muscles in the study and control groups retained contractility showing no evidence of muscle denervation. Our date demonstrates that intramuscular dissection of perforator vessels in the DIEP flap leads to minimal changes in the local morphology and contractility of the rectus abdominis muscle.