Volumetric High-Resolution X-Ray Phase-Contrast Virtual Histology of Breast Specimens With a Compact Laboratory System.

The assessment of margin involvement is a fundamental task in breast conserving surgery to prevent recurrences and reoperations. It is usually performed through histology, which makes the process time consuming and can prevent the complete volumetric analysis of large specimens. X-ray phase contrast tomography combines high resolution, sufficient penetration depth and high soft tissue contrast, and can therefore provide a potential solution to this problem. In this work, we used a high-resolution implementation of the edge illumination X-ray phase contrast tomography based on "pixel-skipping" X-ray masks and sample dithering, to provide high definition virtual slices of breast specimens. The scanner was originally designed for intra-operative applications in which short scanning times were prioritised over spatial resolution; however, thanks to the versatility of edge illumination, high-resolution capabilities can be obtained with the same system simply by swapping x-ray masks without this imposing a reduction in the available field of view. This makes possible an improved visibility of fine tissue strands, enabling a direct comparison of selected CT slices with histology, and providing a tool to identify suspect features in large specimens before slicing. Combined with our previous results on fast specimen scanning, this works paves the way for the design of a multi-resolution EI scanner providing intra-operative capabilities as well as serving as a digital pathology system.

Detection of involved margins in breast specimens with X-ray phase-contrast computed tomography.

Margins of wide local excisions in breast conserving surgery are tested through histology, which can delay results by days and lead to second operations. Detection of margin involvement intraoperatively would allow the removal of additional tissue during the same intervention. X-ray phase contrast imaging (XPCI) provides soft tissue sensitivity superior to conventional X-rays: we propose its use to detect margin involvement intraoperatively. We have developed a system that can perform phase-based computed tomography (CT) scans in minutes, used it to image 101 specimens approximately half of which contained neoplastic lesions, and compared results against those of a commercial system. Histological analysis was carried out on all specimens and used as the gold standard. XPCI-CT showed higher sensitivity (83%, 95% CI 69-92%) than conventional specimen imaging (32%, 95% CI 20-49%) for detection of lesions at margin, and comparable specificity (83%, 95% CI 70-92% vs 86%, 95% CI 73-93%). Within the limits of this study, in particular that specimens obtained from surplus tissue typically contain small lesions which makes detection more difficult for both methods, we believe it likely that the observed increase in sensitivity will lead to a comparable reduction in the number of re-operations.

Magnetic resonance enterography in Crohn's disease: a comparison with the findings at surgery.

AIM: Magnetic resonance (MR) enterography is a radiation-free small bowel investigation which identifies luminal and extra-luminal pathology in patients with Crohn's disease. Most studies have validated MR against conventional radiology. We evaluated the results of MR enterography by comparison with findings at elective surgery for patients with Crohn's disease, including complex pathology. METHOD: Between January 2007 and March 2012 the results of preoperative MR enterography for Crohn's disease in consecutive patients in one unit were compared with the detailed findings at surgery. RESULTS: Fifty-one patients underwent 55 laparotomies during the study period. MR enterography identified the presence of Crohn's disease in the distal ileum in 33/34 patients, in the proximal ileum in 7/12 patients, in the jejunum in 7/8 patients, in the large bowel in 10/11 patients and in the duodenum in one of two patients. MR enterography identified ileo-enteric fistula in 10/12 patients, ileosigmoid fistula in all of seven patients and other fistulae in 10/11 patients. An abscess was identified on MR enterography in eight of nine patients. Within abnormal distal ileal segments, the mean contrast enhancement ratio of acute inflammation was 2.39 ± 0.59 compared with 1.82 ± 0.63 (P < 0.05) in segments with fibrosis only. CONCLUSION: Magnetic resonance enterography identifies small bowel Crohn's disease with an accuracy similar to or better than those of previously published series. Fistulation, abscess formation and large bowel disease can be reliably identified and disease activity assessed. Normal, uninvolved small bowel length can also be measured. Discrete proximal small bowel lesions may not always be detected. In our practice, MR enterography has replaced conventional radiology in the assessment of symptomatic patients with Crohn's disease.

Diagnostic accuracy of high-resolution MR enterography in Crohn's disease: comparison with surgical and pathological specimen.

AIM: To determine the accuracy of high-resolution magnetic resonance enterography (HR-MRE) against surgical and histopathology standards in Crohn's disease, and to determine quantitative MRE findings that can differentiate minor from advanced bowel inflammation. MATERIALS AND METHODS: Forty-nine consecutive patients who underwent 51 surgical procedures underwent standard MRE and HR-MRE prior to surgery. MRE images were assessed for superficial ulcers, deep ulcers, abscesses, fistulae, and strictures. Quantitative MRE parameters, such as mural thickness, enhancement ratios (ER) of the abnormal bowel, mesentery (ME), and normal bowel (controls), were recorded. MRE findings were compared with surgical and histological results to obtain sensitivity, specificity, and accuracy. Grading of inflammation was compared with MRE parameters for correlation and discriminating power. RESULTS: The sensitivities and specificities of MRE and HR-MRE enterography in the detection of abnormal segments were 0.82 and 0.95 versus 0.86 and 0.95 respectively. HR-MRE was significantly more sensitive than MRE and HR-MRE in the detection of superficial and deep ulcers, fistulae, and abscesses (0.5 versus 0.69; 0.69 versus 0.94; 0.76 versus 0.95; 0.77 versus 1.0, respectively). Mural thickness, ER, and ME had positive correlation with higher grades of inflammation(r = 0.8, 0.66, 0.42, respectively). Regression analysis showed deep and superficial ulcers, ER > 1.85 and mural thickness >4.5 mm were independent predictors of advanced inflammation. CONCLUSION: HR-MRE has significantly greater diagnostic accuracy as compared to MRE in the diagnosis of bowel ulceration, fistulae and abscesses. Bowel ulcers, mural enhancement ratio >1.85 are strong predictors of advanced inflammation.

Role of MRI in Crohn's disease.

The traditional imaging of Crohn's disease has relied on barium and computed tomography (CT) examinations. In recent years magnetic resonance imaging (MRI) has emerged as an imaging method that can be used in the diagnosis and assessment of Crohn's disease. The advantages of MRI include lack of ionizing radiation and its superior tissue contrast resolution. The clinical progression of Crohn's disease can be variable, and MRI can be used to assess inflammatory status, disease progression, and complications of Crohn's disease. MRI of the small bowel is an evolving technique and it has the potential to become the preferred technique for imaging of small bowel Crohn's disease in the future.

Biointegrated hydroxylapatite-coated implant fixation of facial prostheses.

This pilot study reports the 2-year follow-up on hydroxylapatite-coated nonscrew titanium implants (Integral) used for fixation of auricular and orbital prostheses. Fifty-four implants have been inserted in a two-stage procedure for auricular reconstruction in 12 patients and orbital reconstruction in 2 patients. Clinically solid integration has occurred with 51 implants in 13 patients, three implants being lost in previously irradiated bone where soft tissue coverage was never adequate. Early soft tissue reaction occurred in those younger patients and where multiple previous surgery had occurred in the same area. Conservative local treatment produced resolution of this in all patients. Stable retention of cosmetically acceptable orbital prostheses was achieved with bar-clip assembly or magnet arrangements.

The prevalence of altered sensation associated with implant surgery.

Trauma to branches of the mandibular nerve may occur during oral surgical procedures and result in varying degrees of altered sensation. Since mandibular implant surgery involves mucoperiosteal flap elevation and bone removal during site preparation, complications involving altered sensation are to be expected. This study replicated a retrospective questionnaire study carried out in Toronto, Canada, and showed that the prevalence of altered sensation in implant patients in Adelaide, Australia (36%) was consistent with that found in Toronto (37%). These data reflect the incidence of altered sensation reported for similar oral surgical procedures and suggest that further characterization of this complication following mandibular implant surgery is necessary.

Hydroxyapatite-coated implants in maxillofacial prosthetics.

The use of implants provides a secure, comfortable, and emotionally satisfactory attachment of the patient to the prosthesis. It is anticipated that patients who are willing to undergo placement of implants would have a greater commitment to continued use of their prostheses. Clearly, there is a greater affinity between a patient and his or her prosthesis when the attachment is an intimate one. The use of implants, then, could reverse functional deficiencies and raise the quality of the patient's post-disease life.

Peptic ulcer disease.

Many of the drugs available for treating peptic ulcer disease have a series of possible overlapping actions on various stages both of acid suppression and mucosal defence, but in certain situations one drug may be better than another. More research is needed to clarify the aetiology of peptic ulcer disease so that treatment can be improved.

Effects of pretreatment sterilization and cleaning methods on materials properties and osseoinductivity of a threaded implant.

A new endosseous titanium implant has been designed to replace skin adhesives as a method of retention of maxillofacial prostheses. The effects of various methods of preimplantation preparation on surface characteristics of the implant were analyzed with electron spectroscopy for chemical analysis. Having undergone one of several pretreatment protocols, fixtures were implanted in the crania of Yucatan miniature hairless swine. Both argon radiofrequency glow discharge and ultraviolet chamber treated implants were associated with the rapid ingrowth and maturation of new bone around the fixture. Conventional steam sterilization was associated with a paucity of neo-osteogenesis accompanied by the production of thick collagen slings at the interface. Apparently, the bulk material, fixture design, and method of surface preparation all contribute to the ultimate clinical fate of an implant.

Effect of mobile paramedic units on outcome in patients with myocardial infarction.

To investigate the effect of mobile paramedic units on outcome, we prospectively studied for two years all patients with myocardial infarction admitted to the LDS Hospital emergency department who sought aid prior to cardiac arrest. One hundred thirty-four patients who received prehospital care from a mobile paramedic unit were compared with 101 patients who selected another means of initial care. Mortality, occurrence of life-threatening arrhythmias, and change in Killip class at 24 and 48 hours were the outcome variables. Data analysis by multiple logistic regression revealed that outcome was not improved, but a 29-minute median delay in hospital arrival occurred in paramedic-treated patients. Defibrillation was the only beneficial treatment performed by paramedics that could be identified. Current mobile paramedic unit procedures may need to be streamlined to eliminate the delay in hospital arrival resulting from extensive prehospital care.

Selection of patients for surgery following peptic ulcer haemorrhage.

Surgery remains the only widely available and well-proven means of stopping haemorrhage from peptic ulcers and preventing its recurrence but carries an unavoidable morbidity. If surgery is to be used to maximum effect with minimum morbidity, an accurate means of predicting which patients will suffer further haemorrhage is needed. Although over 80 per cent of patients who rebleed have the endoscopic stigmata of haemorrhage, a policy of operation in all patients with stigmata would lead to a very high operation rate and a high proportion of unnecessary operations, as one-half of the patients with stigmata do not rebleed. Clinical data were collected prospectively from 278 cases of peptic ulcer haemorrhage. The data from a randomly selected 75 per cent of the cases were analysed by stepwise logistical regression. Patients who had the endoscopic stigmata of haemorrhage and who had a probability of further haemorrhage, calculated from the regression equation, of more than 0.2 were identified as a high risk group. This definition was validated using the 25 per cent of cases not used in the initial analysis. Eighty-four per cent of patients in the high risk group suffered further haemorrhage and all such patients therefore require early surgery: such a policy would have resulted in an operation rate of 28 per cent. Thirty per cent of the patients who had further haemorrhage were not identified as being at high risk but none of them had a severe rebleed. The regression equation greatly enhanced the value of stigmata in guiding surgical decision making and merits further evaluation.

Per-endoscopic bipolar diathermy coagulation of visible vessels using a 3.2 mm probe--a randomised clinical trial.

Forty-four patients who had bled from peptic ulcers and whose ulcers showed stigmata of haemorrhage (bleeding, visible vessel or adherent clot) entered a trial of treatment with a 3.2 mm bipolar diathermy probe. Two patients had spurting haemorrhage when endoscoped and both were treated with the probe, control being obtained in one. The remaining patients were randomised to treatment or control groups. One patient who was treated was withdrawn because the ulcer proved to be malignant. Six of 20 treated patients rebled compared with 8 of 21 controls (relative risk 0.79; 90% CI 0.26-1.97). The operation rate, transfusion requirement and hospital stay were similar in the two groups. One perforation occurred in the treatment group. Per-endoscopic bipolar diathermy treatment confers little benefit in bleeding peptic ulcer disease.

A randomized controlled trial of variceal compression as an adjunct to endoscopic variceal sclerosis.

Endoscopic variceal sclerosis is effective at eradicating oesophageal varices and prolonging survival, but early rebleeding before varices have been obliterated remains a problem. A randomized controlled trial was therefore conducted to determine whether more rapid variceal obliteration and hence a lower morbidity and mortality in the first month could be achieved by compressing the varices after the first injection of sclerosant. Forty patients bleeding from previously untreated varices were studied. There was no demonstrable benefit from post-sclerosis variceal compression in terms of early death from rebleeding (compression, 3 of 19; no compression, 3 of 21 in the first month), total number of patients rebleeding (compression, 5 of 19; no compression, 6 of 21 in the first month), or speed of variceal obliteration (percentage of variceal columns obliterated at 1 month: compression, 13%; no compression, 26%). This study shows that post-sclerosis variceal compression by means of the Williams overtube and Sengstaken tamponade does not improve the efficacy of endoscopic variceal sclerosis.