Interstitial photodynamic therapy – What we have learned from spectral online monitoring and medical imaging

Applications of photodynamic therapy and diagnosis are widely spread over many medical disciplines [1]. Optical dosimetry calculations that include the estimation of thermal effects [2-3] are inevitable to guarantee a sufficient disease control while at the same time preserving tissue at risk [4]. Optical monitoring in an interstitial setting has turned out to be very elucidating, both regarding the initial state of the tissue to be treated, and regarding therapy-induced changes of the optical properties of the tissue [5-7], beyond the assessment of photobleaching. This information can be utilized immediately in the surgery room, to individualize, monitor and optimize the therapy session, as well as to warrant and optimize patient safety. Furthermore, by combining all available information around a PDT intervention, further insight about the involved processes and mechanisms can be gained [5-6], which can be utilized to develop the therapeutic approach further as a whole. As an example, the quite promising clinical outcome of iPDT treatments on malignant brain tumors will be summarized [7-8] and evaluation concepts based on spectral online monitoring and medical imaging [5-7], before and after the intervention, will be illustrated. iPDT-induced effects, including conversion of hemoglobin, will be discussed in relation to tumor coverage by the illumination volume and the location of recurrences.     

What do we expect from imaging?

The objectives of imaging in gynecologic cancer include tumor detection, tumor diagnosis, staging, and follow-up. In addition, both monitoring response to treatment and differentiating tumor recurrence from post-treatment changes are important indications for imaging. In 2001 it was estimated that there would be 38,300 cases of endometrial cancer, 23,400 cases of ovarian cancer, and 12,900 cases of cervical cancer. This article reviews what information is required by the practicing gynecologist or gynecologic oncologist prior to surgery and briefly summarizes state-of-the-art imaging in answering clinically pertinent questions.     

What have we learned from CONFIRM? Prognostic implications from a prospective multicenter international observational cohort study of consecutive patients undergoing coronary computed tomographic angiography

Coronary computed tomographic angiography (CCTA) employing CT scanners of 64-detector rows or greater represents a novel non-invasive method for detection of coronary artery disease (CAD), providing excellent diagnostic information when compared to invasive angiography. In addition to its high diagnostic performance, prior studies have shown that CCTA can provide important prognostic information, although these prior studies have been generally limited to small cohorts at single centers. The Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter registry, or CONFIRM, is a large, prospective, multinational, dynamic observational cohort study of patients undergoing CCTA. This registry currently represents more than 32,000 consecutive adults suspected of having CAD who underwent ??64-detector row CCTA at 12 centers in 6 countries between 2005 and 2009. Based on its large sample size and adequate statistical power, the data derived from CONFIRM registry have and will continue to provide key answers to many important topics regarding CCTA. Based on its multisite international national design, the results derived from CONFIRM should be considered as more generalizable than prior smaller single-center studies. This article summarizes the current status of several studies from CONFIRM registry.     

The randomized trials of breast cancer screening: what have we learned?

Eight randomized controlled trials of mammography screening have been conducted to date. In addition to evaluating the efficacy of screening with an experimental design, the trials provided investigators with access to information about breast cancers much earlier in their development than had previously been available. The trials of mammographic screening provide conclusive evidence that the policy of offering screening is associated with a significant and substantial reduction in breast cancer mortality.     

Fixed- versus mobile-bearing unicondylar knee arthroplasty: are failure modes different?

Purpose

An ongoing controversy exists on whether mobile-bearing design is superior over fixed-bearing design in unicondylar knee arthroplasties (UKAs). The present study conducted a systematic review to ascertain differences in performance between fixed- and mobile-bearing designs in UKAs.

Methods

A literature search was performed in PubMed, Embase, Scopus and the Cochrane Library. A total of 9 comparative studies involving 915 knees comparing outcomes of mobile-bearing UKAs with fixed-bearing UKAs were included in the current analysis. Outcomes of interest included knee function, quality of life, radiographic outcomes, reasons and incidence of reoperation, timing of failures, and survivorship.

Results

The results presented no significant differences between the two designs in terms of knee scores, range of motion, limb alignment, implant positioning, incidence of radiolucent lines and overall reoperation rates. However, their differences have been noted in their modes and timing of failures. Early failures are related to the risk of bearing dislocation in the mobile-bearing design. In contrast, later failures are related to the risk of polyethylene wear in the fixed-bearing design.

Conclusions

The available evidence has not confirmed the advantage of mobile-bearing UKAs over fixed-bearing UKAs but pointed out specific modes of failure.

Level of evidence

Therapeutic study (systematic review and meta-analysis), Level III.     

A historical perspective on the specific activity of radiopharmaceuticals: What have we learned in the 35 years of the ISRC?

Specific Activity (SA), defined as the amount of radioactivity per unit mass of a compound is arguably one of the most important parameters in radiopharmaceutical development, particularly in quality control of carbon-11 and fluorine-18 labeled compounds. This review article will outline the progression of improvements in SA over the last few decades. The International Symposium of Radiopharmaceutical Chemistry (ISRC/ISRS) abstracts were an excellent source of materials for this review and will be referenced throughout.     

Plaque progression: Where,why, and how fast? A review of what we have learned from the analysis of patient data from the PARADIGM registry

Ischemic heart disease is the most common cause of mortality worldwide. The pathophysiology of myocardial infarction relates to temporal changes of atherosclerotic plaque culminating in plaque rupture, erosion or hemorrhage and the subsequent thrombotic response. Coronary computed tomographic angiography (CCTA) provides the ability to visualize and quantify plaque, and plaque progression can be measured on a per-patient basis by comparing findings of serial CCTA. The Progression of AtheRosclerotic PlAque DetermIned by Computed TomoGraphic Angiography IMaging (PARADIGM) registry was established with the objective of identifying patterns of plaque progression in a large population. The registry comprises over 2000 patients with multiple CCTA scans performed at least two years apart. Unlike previous CCTA registries, a semi-automated plaque quantification technique permitting detailed analysis of plaque progression was performed on all patients with interpretable studies. Since the registry was established, 19 peer-reviewed publications were identified, and all are reviewed and summarized in this article.     

Re-thinking clinical assessment: What can we learn from the medical literature?

This article explores the literature available in the field of medical education on the topic of clinical assessment, in order to suggest different ways of assessing clinical experience that may not have been considered within undergraduate radiography programmes. The medical literature is contrasted with the clinical assessment currently being used in a medical imaging programme in New Zealand, with the aim of offering suggestions that may benefit the assessment of the clinical and professional elements of radiography programmes more generally.The authors conclude that ideally students need to be assessed in the clinical domain by multiple assessors, with varied assessment methods used repeatedly over a period of time and with the provision of frequent and constructive feedback. Various methods of clinical assessment are suggested and it is emphasised that the methods selected need to be valid, reliable and psychometrically supported. This encourages an evidence-based practice approach that is supportive of on-going programme development and change.     

Prediction of range of motion 2?years after mobile-bearing total knee arthroplasty: PCL-retaining versus PCL-sacrificing

Purpose  

This study evaluated the changes in the range of motion (ROM) with time postoperatively.     

Should we resurface the patella in total knee replacement?

Patellar resurfacing is a controversial issue in primary total knee replacement. So, we took advantage of a large study to try and answer this question. An open prospective multicentric study was conducted about the outcome of the Nex Gen Total Knee prosthesis with clinical and radiological follow-up at regular intervals (1, 2 and 5 years). The data were centrally collected and analyzed by independent observers. A total of whole 5,915 cases were included (487 in the French group); incidences of patello-femoral pain were observed in both French and international groups and compared between cases with or without resurfaced patellae. Only osteoarthritic cases were selected for this particular study. Statistical analysis was performed using a Pearsons Chi-square test with a 95% confidence interval. The frequency of preoperative pain was significantly higher in the French group; 85.1% versus 66.6% (p<0.05). No patello-femoral pain appeared in preoperatively painless patients in the French group. The frequency of lateral patellar release was similar in both groups. 35.7% of the patellae were resurfaced in the international group versus 98.8% in the French one. At 2 years, patello-femoral pain was observed in 6.3% of cases in the former group versus 0.7% in the latter one. The risk of having patello-femoral pain was 9.45 times higher in the international group. When considering resurfaced cases in both groups the risk of having anterior knee pain was not significantly different (p=0.35). In the French group, one case out of nine (11.1%) with patello-femoral pain had not been resurfaced, while 129 cases out of 151 (85.4%) had not had a resurfacing in the international group. This emphasizes the effect of patellar implant on pain. Although patello-femoral pain is multifactorial, this analysis tool is powerful in getting rid of the center effect (cf Swedish register). Even if a longer follow-up for confirmation is needed, our data favor patellar resurfacing with this type of implant in spite of the fact that the trochlear design was considered as anatomical.     

Fingerprint identification: how far have we come?

Fingerprint identification has been an accepted forensic discipline for more than 110 years. But how far have we come with respect to the interpretation and reporting of fingerprint evidence? Should the discipline follow the DNA lead and introduce mathematical models for the assessment of fingerprint evidence, with the ‘statistic' – the number generated by the model – then becoming the evidence presented in court? Further to this, and with respect to evidence that can be given a statistical value, to what extent are we meeting our professional obligation to ensure that the weight of the evidence we present in court is fully understood and not misinterpreted?     

CT colonography: where have we been and where are we going?

Over the past decade, computed tomographic (CT) colonography (also known as virtual colonoscopy) has been used to investigate the colon for colorectal neoplasia. Numerous clinical and technical advances have allowed CT colonography to advance slowly from a research tool to a viable option for colorectal cancer screening. However, substantial controversy remains among radiologists, gastroenterologists, and other clinicians with regard to the current role of CT colonography in clinical practice. On the one hand, all agree there is much excitement about a noninvasive imaging examination that can reliably depict clinically important colorectal lesions. However, this is tempered by results from several recent studies that show the sensitivity of CT colonography may not be as great when performed and the images interpreted by radiologists without expertise and training. The potential to miss important lesions exists; moreover, if polyps cannot be differentiated from folds and residual fecal matter, unnecessary colonoscopy will be performed. In this review, current issues will be discussed regarding colon cancer and the established and reimbursed strategies to screen for it and the past, current, and potential future role of CT colonography.     

Is there any superiority in the clinical outcome of mobile-bearing knee prosthesis designs compared to fixed-bearing total knee prosthesis designs in the treatment of osteoarthritis of the knee joint?

To substantiate the validity and relevance of the mobile-bearing knee prosthesis design compared to the fixed-bearing design, concerning the clinical outcome, this review was conducted. Articles published in 6 major orthopaedic journals were screened. Only randomized controlled trials, which investigate the clinical outcome, were included. The clinical outcome parameters of each study were analysed. Despite the numerous quantities of publications in orthopaedic literature, we could conclude, that only a few of them are randomized controlled trials. Although better kinematics of mobile-bearing knee prosthesis designs compared to fixed-bearing knee prosthesis designs are reported, no superiority of one of the bearing designs concerning clinical outcome could be revealed. Because no superiority of one of the designs concerning revision rate, survival and outcome can be found, the cheaper one should be the one to be recommended. For this reason, we advise that further research, comparing the costs and cost-benefit of mobile-bearing compared to fixed-bearing knee prosthesis designs, should be performed.