Factors Contributing to Delays to Accessing Appendectomy in Low- and Middle-Income Countries: A Scoping Review

BACKGROUND

Appendicitis is one of the most common emergency surgical conditions worldwide. Delays in accessing appendectomy can lead to complications. Evidence on these delays in low- and middle-income countries (LMICs) is lacking. The aim of this review was to identify and synthesise the available evidence on delays to accessing appendectomy in LMICs.

METHODS

This scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis Extension for Scoping Reviews framework. The delays and their interconnectivity in LMICs were synthesised and interpreted using the Three Delays framework. We reviewed Africa Wide EBSCOhost, PubMed-Medline, Scopus, Web of Science, African Journals Online (AJOL), and Bioline databases.

RESULTS

Our search identified 21 893 studies, of which 78 were included in the final analysis. All of the studies were quantitative. Fifty per cent of the studies included all three types of delays. Delays in seeking care were influenced by a lack of awareness of appendicitis symptoms, and the use of self and alternative medication, which could be linked to delays in receiving care, and the barrier refusal of medical treatment due to fear. Financial concerns were a barrier observed throughout the care pathway.

CONCLUSION

This review highlighted the need for additional studies on delays to accessing appendectomy in additional LMICs. Our review demonstrates that in LMICs, persons seeking appendectomy present late to health-care facilities due to several patient-related factors. After reaching a health-care facility, accessing appendectomy can further be delayed owing to a lack of adequate hospital resources.

Evaluating a novel patient pathway to manage symptomatic breast referrals (the blue flag clinic): a longitudinal observational study

INTRODUCTION

A novel referral pathway for exhibited breast symptom (EBS) referrals to manage increasing referrals of urgent suspected cancer (USC) was implemented in our trust. We report on the safety and effect on compliance with the 2-week-wait rule (2WW).

METHODS

A single-centre longitudinal observational study included all patients referred to a UK breast unit during 13 May 2019 to 27 March 2020 (period 1) and 8 February 2021 to 31 January 2022 (period 2). USC referrals were assessed in a one-stop clinic (red flag clinic [RFC]); EBS referrals were assessed in a new clinic in which clinical evaluation was performed and imaging occurred subsequently (blue flag clinic [BFC]). Patients were followed up to determine the symptomatic interval cancer rate.

RESULTS

There were 9,695 referrals; 1,655 referrals (17%) were assessed in the BFC after 63 exclusions. Some 95.9% of patients had a benign clinical examination (P1/P2), 80.1% had imaging (mammogram or ultrasound) and 4% had a tissue biopsy. In total, 16/1,655 (0.97%) BFC patients and 510/7,977 (8.2%) RFC patients were diagnosed with breast cancer (breast cancer detection rate). Some 1,631 patients (with 1,639 referrals) were discharged and followed up for a median of 17 months (interquartile range 12-32) with one subsequent cancer diagnosis (symptomatic interval cancer rate, 0.06%). Implementation of the BFC pathway increased 3-month average trust performance of USC referrals with 2WW standard from 8.5% to 98.7% (period 1) and from 30% to 66% (period 2).

CONCLUSIONS

The BFC pathway for EBS patients is safe and implementation led to improvement against the 2WW target for USC referrals, ensuring resources are prioritised to patients with the highest likelihood of breast cancer.

Monitoring Cochlear Health With Intracochlear Electrocochleography During Cochlear Implantation: Findings From an International Clinical Investigation

OBJECTIVES

Electrocochleography (ECochG) is emerging as a tool for monitoring cochlear function during cochlear implant (CI) surgery. ECochG may be recorded directly from electrodes on the implant array intraoperatively. For low-frequency stimulation, its amplitude tends to rise or may plateau as the electrode is inserted. The aim of this study was to explore whether compromise of the ECochG signal, defined as a fall in its amplitude of 30% or more during insertion, whether transient or permanent, is associated with poorer postoperative acoustic hearing, and to examine how preoperative hearing levels may influence the ability to record ECochG. The specific hypotheses tested were threefold: (a) deterioration in the pure-tone average of low-frequency hearing at the first postoperative follow-up interval (follow-up visit 1 [FUV1], 4 to 6 weeks) will be associated with compromise of the cochlear microphonic (CM) amplitude during electrode insertion (primary hypothesis); (b) an association is observed at the second postoperative follow-up interval (FUV2, 3 months) (secondary hypothesis 1); and (c) the CM response will be recorded earlier during electrode array insertion when the preoperative high-frequency hearing is better (secondary hypothesis 2).

DESIGN

International, multi-site prospective, observational, between groups design, targeting 41 adult participants in each of two groups, (compromised CM versus preserved CM). Adult CI candidates who were scheduled to receive a Cochlear Nucleus CI with a Slim Straight or a Slim Modiolar electrode array and had a preoperative audiometric low-frequency average thresholds of ≤80 dB HL at 500, 750, and 1000 Hz in the ear to be implanted, were recruited from eight international implant sites. Pure tone audiometry was measured preoperatively and at postoperative visits (FUV1 and follow-up visit 2 [FUV2]). ECochG was measured during and immediately after the implantation of the array.

RESULTS

From a total of 78 enrolled individuals (80 ears), 77 participants (79 ears) underwent surgery. Due to protocol deviations, 18 ears (23%) were excluded. Of the 61 ears with ECochG responses, amplitudes were < 1 µV throughout implantation for 18 ears (23%) and deemed "unclear" for classification. EcochG responses >1 µV in 43 ears (55%) were stable throughout implantation for 8 ears and compromised in 35 ears. For the primary endpoint at FUV1, 7/41 ears (17%) with preserved CM had a median hearing loss of 12.6 dB versus 34/41 ears (83%) with compromised CM and a median hearing loss of 26.9 dB ( p < 0.014). In assessing the practicalities of measuring intraoperative ECochG, the presence of a measurable CM (>1 µV) during implantation was dependent on preoperative, low-frequency thresholds, particularly at the stimulus frequency (0.5 kHz). High-frequency, preoperative thresholds were also associated with a measurable CM > 1 µV during surgery.

CONCLUSIONS

Our data shows that CM drops occurring during electrode insertion were correlated with significantly poorer hearing preservation postoperatively compared to CMs that remained stable throughout the electrode insertion. The practicality of measuring ECochG in a large cohort is discussed, regarding the suggested optimal preoperative low-frequency hearing levels ( < 80 dB HL) considered necessary to obtain a CM signal >1 µV.

Access to health care for people with stroke in South Africa: a qualitative study of community perspectives

BACKGROUND

Incidence of stroke is increasing in sub-Saharan Africa. People who survive stroke experience disability and require long-term care. Health systems in South Africa (SA) are experiencing important challenges, and services in the public health system for people with stroke (PWS) are fragmented. We aimed to explore the perspectives and experiences of PWS related to stroke care services to inform health system strengthening measures.

METHODS

In-depth interviews with 16 PWS in urban and rural areas in the Western and Eastern Cape Provinces of SA were conducted between August and October 2020. PWS were recruited through existing research networks, non-government organisations and organisations of persons with disabilities by snowball sampling. Interviews were transcribed, coded, and thematically analysed. We used the conceptual framework of access to health care as proposed by Levesque et al. to map and inform barriers to accessing health care from the user perspective.

RESULTS

PWS recognised the need for health care when they experienced signs of acute stroke. Health literacy on determinants of stroke was low. Challenges to accessing stroke care include complex pathways to care, physical mobility related to stroke, long travel distances and limited transport options, waiting times and out of pocket expenses. The perceived quality of services was influenced by cultural beliefs, attitudinal barriers, and information challenges. Some PWS experienced excellent care and others particularly poor care. Positive staff attitude, perceived competence and trustworthiness went in hand with many technical and interpersonal deficits, such as long waiting times and poor staff attitude that resulted in poor satisfaction and reportedly poor outcomes for PWS.

CONCLUSIONS

Strategic leadership, governance and better resources at multiple levels are required to address the unmet demands and needs for health care of PWS. Stroke care could be strengthened by service providers routinely providing information about prevention and symptoms of stroke, treatment, and services to patients and their social support network. The role of family members in continuity of care could be strengthened by raising awareness of existing resources and referral pathways, and facilitating connections within services.

A Culturally Relevant Smartphone-Delivered Physical Activity Intervention for African American Women: Development and Initial Usability Tests of Smart Walk

Background

Smart Walk is a culturally relevant, social cognitive theory–based, smartphone-delivered intervention designed to increase physical activity (PA) and reduce cardiometabolic disease risk among African American (AA) women.

Objective

This study aimed to describe the development and initial usability testing results of Smart Walk.

Methods

Smart Walk was developed in 5 phases. Phases 1 to 3 focused on initial intervention development, phase 4 involved usability testing, and phase 5 included intervention refinement based on usability testing results. In phase 1, a series of 9 focus groups with 25 AA women (mean age 38.5 years, SD 7.8; mean BMI 39.4 kg/m2, SD 7.3) was used to identify cultural factors associated with PA and ascertain how constructs of social cognitive theory can be leveraged in the design of a PA intervention. Phase 2 included the analysis of phase 1 qualitative data and development of the structured PA intervention. Phase 3 focused on the technical development of the smartphone app used to deliver the intervention. Phase 4 consisted of a 1-month usability trial of Smart Walk (n=12 women; mean age 35.0 years, SD 8.5; mean BMI 40 kg/m2, SD 5.0). Phase 5 included refinement of the intervention based on the usability trial results.

Results

The 5-phase process resulted in the development of the Smart Walk smartphone-delivered PA intervention. This PA intervention was designed to target social cognitive theory constructs of behavioral capability, outcome expectations, social support, self-efficacy, and self-regulation and address deep structure sociocultural characteristics of collectivism, racial pride, and body appearance preferences of AA women. Key features of the smartphone app included (1) personal profile pages, (2) multimedia PA promotion modules (ie, electronic text and videos), (3) discussion boards, and (4) a PA self-monitoring tool. Participants also received 3 PA promotion text messages each week.

Conclusions

The development process of Smart Walk was designed to maximize the usability, cultural relevance, and impact of the smartphone-delivered PA intervention.

A 58-Year-Old Man With Fatigue, Weight Loss, and Diffuse Miliary Pulmonary Opacities

CASE PRESENTAION

A 58-year-old man presented with a 6-month history of profound fatigue and a weight loss of 35 to 40 pounds. He reported occasional night sweats and mildly painful knees and elbows without swelling or redness. He denied respiratory symptoms, rashes, or fevers. He had no respiratory symptoms. The patient's history was significant for rheumatoid arthritis (with arthralgias and joint involvement), paroxysmal atrial fibrillation, and hypothyroidism. His medications included digoxin and metoprolol. He had been taking methotrexate and low-dose prednisone (5 mg) for approximately 10 years but discontinued taking these medications 2 years prior to current presentation. Originally from West Virginia, the patient had relocated to Arizona during the early 1980s. There was no history of international travel or TB. He had no exposure history to birds, bird feathers, or mold; however, he did report exposure to dust at his current job as a home building superintendent. He reported a 10 pack-year history of smoking, having quit 20 years ago. His family history was significant for renal sarcoidosis in his mother.

Enhanced Excitotoxicity in Primary Feline Neural Cultures Exposed to Feline Immunodeficiency Virus (FIV)

The ability of feline immunodeficiency virus (FIV) to induce neurodegenerative changes in vitro similar to those due to HIV was examined as a potential model to examine the mechanisms underlying AIDS dementia. Primary cultures of feline neural tissue (neurons, astrocytes and microglia) were established from E40-E57 fetal cat cortex and challenged by inoculation with the NCSU₁ strain of FIV. Proviral FIV was detected in the cultures and correlated with the presence of microglia. No direct toxicity of FIV was seen. Stimulation of FIV-inoculated cortical cultures with 20 uM glutamate resulted in a greatly enhanced acute swelling response in approximately 14-24% of the neurons and an increase in the number of dead cells after 24 h relative to control cultures. The enhanced responses were due to an increase in the sensitivity of the cells to glutamate and were dependent on the presence of a soluble factor in the medium. The similarity of the indirect excitoxic effects of FIV to current models of HIV-gp120 neurotoxicity and the versatility of the in vitro cultures, indicate that FIV should provide a valuable model for the investigation of the mechanisms of neurodegeneration in AIDS dementia.

Randomized clinical trial on the effect of fibrin sealant on latissimus dorsi donor-site seroma formation after breast reconstruction

BACKGROUND

Latissimus dorsi (LD) flap procedures comprise 50 per cent of breast reconstructions in the UK. They are frequently complicated by seroma formation. Fibrin sealants may reduce seroma volumes at the donor site. The aim was to investigate the effect of fibrin sealant (Tisseel(®)) on total seroma volumes from the breast, axilla and back (donor site) after LD breast reconstruction. Secondary outcomes were specific back seroma volumes together with incidence and severity of wound complications.

METHODS

Consecutive women undergoing implant-assisted or extended autologous LD flap reconstruction were randomized to either standard care or application of fibrin sealant to the donor-site chest wall. All participants were blinded for the study duration but assessors were only partially blinded. Non-parametric methods were used for analysis.

RESULTS

A total of 107 women were included (sealant 54, control 53). Overall back seroma volumes were high, with no significant differences between control and sealant groups over 3 months. Fibrin sealant failed to reduce in situ back drainage volumes in the 10 days after surgery, and did not affect the rate or volume of seromas following drain removal.

CONCLUSION

This randomized study, which was powered for size effect, failed to show any benefit from fibrin sealant in minimizing back seromas after LD procedures.

P2-16-07: A Randomised Controlled Trial To Evaluate the Role of Tisseel, a Fibrin Sealant on Seroma Formation in Latissimus dorsi Breast Reconstruction

Introduction: Donor site seromas are common complications following Latissimus dorsi breast reconstructions (LDBR), as shown in the UK National Mastectomy and Breast Reconstruction audit. Level I clinical evidence following the performance of an RCT supports ‘fixation’ of the back skin flaps by quilting sutures1. Fibrin sealants (Tisseel) have been postulated to reduce seromas after simple mastectomy and axillary dissections2, but their role in reducing donor site seromas after breast reconstruction has yet to be performed in a ‘robust’ clinical trial. The aim of this RCT was to compare Tisseel against Control (no Tisseel) on the incidence of seromas after LDBR.

Methods: In an ethics approved single centre, single-blinded study comprising 2 surgeons from 2005–2010; 106 women were randomised to either Control (52) or Tisseel (54) interventions after immediate or delayed breast reconstructions. Sixteen patient's were excluded as follows due to incomplete data at 3 months or re-operations of the donor site for complications. The types of breast reconstructions comprised implant-assisted LD (LDI) in 45 women, 23 extended LD flaps (ELD) and 23 ELD with implant (ELDI). Immediate breast reconstructions (n=87) comprised the majority compared to only 4 delayed procedures. Intraoperative drains were placed to the breast, axilla and donor site (x two) as per standard practice. A 0.5% fibrinogen concentration was used in a hydraulic hand-held Tisseel spray application to the donor site chest wall over 60 seconds. Two stay sutures were pre-placed 2 cm adjacent to the donor wound skin edges above and below prior to the Tisseel application. In the control group, 2 drains only were placed. The primary outcome measure was the total seroma volumes from all the sites over 3 months. This was used for the power calculation of the sample size and showed a requirement for a minimum of 95 women. Secondary outcomes included the volumes of the donor site seromas, and the frequency of post-drain removal donor site aspirations of all symptomatic seromas by patient self-report.

Results: The effect of Tisseel glue was to reduce the mean total drain (breast, axilla and back) volume from 2170ml to 1919ml (P=0.05, Mann-Whitney) within 7–10 days. The donor site seroma volumes were similar between the 2 groups over 3 months. The mean donor site total drain volumes (LD donor site drain volume and symptomatic donor site aspirations) were 5412ml in the Control group (840-6252), compared to the Tisseel group producing 4646ml (5384-738). There were no statistical differences between the frequencies or volumes of patient reported seromas aspirated post-drain removal between the two groups. This comprised a mean of 4 aspirations (range 0–13) in the Control group compared to a mean of 9 aspirations (range 0–11) after the use of Tisseel (P=0.548).

Conclusion: Tisseel glue may reduce the ‘early’ effect of seroma development, but has not shown any significant role in minimising the potential ‘shearing’ of the donor site skin flaps causing later seroma formation. Current evidence recommends quilting sutures as the gold-standard in reducing this complication.

1. Daltrey I et. al. BJS 2006; 93(7):825–830.

2. Jain PK et. al. BJS 2004; 91:54–60.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-16-07.

Building capacity for antiretroviral delivery in South Africa: a qualitative evaluation of the PALSA PLUS nurse training programme

BACKGROUND

South Africa recently launched a national antiretroviral treatment programme. This has created an urgent need for nurse-training in antiretroviral treatment (ART) delivery. The PALSA PLUS programme provides guidelines and training for primary health care (PHC) nurses in the management of adult lung diseases and HIV/AIDS, including ART. A process evaluation was undertaken to document the training, explore perceptions regarding the value of the training, and compare the PALSA PLUS training approach (used at intervention sites) with the provincial training model. The evaluation was conducted alongside a randomized controlled trial measuring the effects of the PALSA PLUS nurse-training (Trial reference number ISRCTN24820584).

METHODS

Qualitative methods were utilized, including participant observation of training sessions, focus group discussions and interviews. Data were analyzed thematically.

RESULTS

Nurse uptake of PALSA PLUS training, with regard not only to ART specific components but also lung health, was high. The ongoing on-site training of all PHC nurses, as opposed to the once-off centralized training provided for ART nurses only at non-intervention clinics, enhanced nurses' experience of support for their work by allowing, not only for ongoing experiential learning, supervision and emotional support, but also for the ongoing managerial review of all those infrastructural and system-level changes required to facilitate health provider behaviour change and guideline implementation. The training of all PHC nurses in PALSA PLUS guideline use, as opposed to ART nurses only, was also perceived to better facilitate the integration of AIDS care within the clinic context.

CONCLUSION

PALSA PLUS training successfully engaged all PHC nurses in a comprehensive approach to a range of illnesses affecting both HIV positive and negative patients. PHC nurse-training for integrated systems-based interventions should be prioritized on the ART funding agenda. Training for individual provider behaviour change is nonetheless only one aspect of the ongoing system-wide interventions required to effect lasting improvements in patient care in the context of an over-burdened and under-resourced PHC system.

The Practical Approach to Lung Health in South Africa (PALSA) intervention: respiratory guideline implementation for nurse trainers

AIM

This paper describes the design, facilitation and preliminary assessment of a 1-week cascade training programme for nurse trainers in preparation for implementation of the Practical Approach to Lung Health in South Africa (PALSA) intervention, tested within the context of a pragmatic cluster randomized controlled trial in the Free State province. PALSA combines evidence-based syndromic guidelines on the management of respiratory disease in adults with group educational outreach to nurse practitioners.

BACKGROUND

Evidence-based strategies to facilitate the implementation of primary care guidelines in low- to middle-income countries are limited. In South Africa, where the burden of respiratory diseases is high and growing, documentation and evaluation of training programmes in chronic conditions for health professionals is limited.

METHOD

The PALSA training design aimed for coherence between the content of the guidelines and the facilitation process that underpins adult learning. Content facilitation involved the use of key management principles (key messages) highlighted in nurse-centred guidelines manual and supplemented by illustrated material and reminders. Process facilitation entailed reflective and experiential learning, role-playing and non-judgemental feedback.

DISCUSSION AND RESULTS

Preliminary feedback showed an increase in trainers' self-awareness and self-confidence. Process and content facilitators agreed that the integrated training approach was balanced. All participants found that the training was motivational, minimally prescriptive, highly nurse-centred and offered personal growth.

CONCLUSION

In addition to tailored guideline recommendations, training programmes should consider individual learning styles and adult learning processes.

Analysis of clinical decision-making in multi-disciplinary cancer teams

Management decisions for patients with cancer are frequently taken within the context of a multi-disciplinary team (MDT). There is little known, however, about decision-making at team meetings and whether MDT decisions are all implemented. This study evaluated team decision-making in upper gastrointestinal cancer. Consecutive MDT treatment decisions were recorded for patients with oesophageal, gastric, pancreatic and peri-ampullary tumours. Implementation of MDT decisions was investigated by examining hospital records. Where decisions were implemented it was recorded as concordant and discordant if the decision changed. Reasons for changes in MDT decisions were identified. 273 decisions were studied and 41 (15.1%) were discordant (not implemented), (95% confidence interval 11.1-20.0%). Looking at the reasons for discordance, 18 (43.9%) were due to co-morbid health issues, 14 (34.2%) related to patient choice and 8 (19.5%) decisions changed when more clinical information was available. For one discordant decision, the reason was not apparent. Discordant decisions were more frequent for patients with pancreatic or gastric carcinoma as compared to oesophageal cancer (P = 0.001). Results show that monitoring concordance between MDT decisions and final treatment implementation is useful to inform team decision-making. For upper gastrointestinal cancer, MDTs require more information about co morbid disease and patient choice to truly optimize the implementation of multi-disciplinary expertise.

Budesonide/formoterol and formoterol provide similar rapid relief in patients with acute asthma showing refractoriness to salbutamol

BACKGROUND

To compare the efficacy and safety of budesonide/formoterol (Symbicort) with formoterol (Oxis) in the treatment of patients with acute asthma who showed evidence of refractoriness to short-acting beta2-agonist therapy.

METHODS

In a 3 hour, randomized, double-blind study, a total of 115 patients with acute asthma (mean FEV1 40% of predicted normal) and a refractory response to salbutamol (mean reversibility 2% of predicted normal after inhalation of 400 microg), were randomized to receive either budesonide/formoterol (320/9 microg, 2 inhalations at t = -5 minutes and 2 inhalations at 0 minutes [total dose 1280/36 microg]) or formoterol (9 microg, 2 inhalations at t = -5 minutes and 2 inhalations at 0 minutes [total dose 36 microg]). The primary efficacy variable was the average FEV1 from the first intake of study medication to the measurement at 90 minutes. Secondary endpoints included changes in FEV1 at other timepoints and change in respiratory rate at 180 minutes. Treatment success, treatment failure and patient assessment of the effectiveness of the study medication were also measured.

RESULTS

FEV1 increased after administration of the study medication in both treatment groups. No statistically significant difference between the treatment groups was apparent for the primary outcome variable, or for any of the other efficacy endpoints. There were no statistically significant between-group differences for treatment success, treatment failure or patient assessment of medication effectiveness. Both treatments were well tolerated.

CONCLUSION

Budesonide/formoterol and formoterol provided similarly rapid relief of acute bronchoconstriction in patients with asthma who showed evidence of refractoriness to a short-acting beta2-agonist.

Predictors of outcome of mammography in the National Health Service Breast Screening Programme

BACKGROUND

Little is known about the factors influencing the risk of recall for assessment, invasive diagnostic procedures, and early rescreening after screening mammography.

METHODS

From June 1996 to March 1998 women attending screening at 10 National Health Service Breast Screening Programme (NHSBSP) centres completed a self administered questionnaire and were followed up for their screening outcome.

RESULTS

1969 (3.3%) out of 60 443 women aged 50-64 who had never used hormone replacement therapy (HRT) were recalled for assessment but were not diagnosed with breast cancer (defined here as false positive recall). After adjustment for the variation between centres, false positive recall was decreased significantly among women who were likely to have had a previous NHSBSP mammogram (odds ratio (OR) 0.49, 95% confidence interval (95% CI) 0.38 to 0.63 for likely versus unlikely), who were postmenopausal (OR 0.65, 95% CI 0.56 to 0.76 for postmenopausal v premenopausal) and increased significantly for women reporting previous breast surgery (OR 1.64, 95% CI 1.42 to 1.89). Although false positive recall decreased significantly with parity and increasing body mass index, these effects were not large and no significant variation was found with age, education, family history of breast cancer, oral contraceptive use, sterilisation, exercise, smoking, or alcohol consumption. Altogether 655 (1.1%) women had an invasive diagnostic procedure; no personal characteristics were predictive of this outcome, 286(0.5%) were referred for early rescreening, and this was increased significantly by nulliparity and a family history of breast cancer.

INTERPRETATION

Premenopausal women, those without a previous NHSBSP mammogram, and women with previous breast surgery have an increased risk of false positive recall by the NHSBSP.

A mammographic dilemma: calcification or haemosiderin as a cause of opacities? Validation of a new digital diagnostic tool

Core biopsies of an area of microcalcification demonstrated large collections of macrophages containing haemosiderin, with evidence of minimal microcalcification on H&E staining. Algorithms were developed that were capable of differentiating with high accuracy those signs due to calcification, using quantitative measurements such as the apparent volume composition of calcium. Using the linear attenuation coefficients of calcification and assuming an ellipsoid model for the 3-dimensional shape of calcification, we computed the relative calcification volume for each region of interest. The difference in the linear attenuation coefficients of iron and calcification allowed the two to be differentiated on a mammogram based on this measure of relative calcification volume.

Fixed implant rehabilitation of the edentulous maxilla: clinical guidelines and case reports. Part II

Fixed prosthetic implant reconstruction of the edentulous maxilla demands skill and state-of-the-art techniques of both the surgeon and the restorative dentist. As discussed in Part I (Implant Dent. 1999;8: 186-193), accurate diagnosis and treatment planning are essential to successful, predictable clinical results. How and where implants are placed have a lasting impact on the quality and prognosis of the final restoration. A series of clinical guidelines and considerations is reviewed with illustrative clinical treatment protocols of edentulous maxillae of unfavorable anatomy including attendant prosthetic difficulties. This article addresses the fixed implant rehabilitation of edentulous maxillas with inadequate posterior bone and favorable arch position, inadequate posterior bone and unfavorable arch position, and inadequate anterior and posterior bone and unfavorable arch position.

Three-dimensional reconstruction of microcalcification clusters from two mammographic views

Classification of benign/malignant microcalcification clusters is a major diagnostic challenge for radiologists. Clinical studies have revealed that the shape of the cluster, and the spatial distribution of individual microcalcifications within it, are important indicators of its malignancy. However, mammographic images of clustered microcalcifications confound their three-dimensional (3-D) distribution with image projection and breast compression. This paper presents a novel model-based method for reconstructing microcalcification clusters in 3-D from two mammographic views (cranio-caudal and medio-lateral oblique--"shoulder to the opposite hip" or lateral-medio). We develop a 3-D breast representation and a parameterised breast compression model which constraints geometrically the possible 3-D positions of a calcification in a two-dimensional image. Corresponding calcifications in the two views are matched using an estimate of the calcification volume. Both the geometric constraint and the matching criterion are utilized in the final reconstruction step to build the 3-D reconstructed clusters. Validation experiments are described using 30 clusters to verify the individual steps of the model, and results consistent with known ground truth are obtained. Some of the approximations in the model and future work are discussed in the concluding section.