Author’s Response to: Letter to Editor

CardioVascular and Interventional Radiology -     

Instructions to authors

GENERAL INFORMATION World Journal of Radiology (World J Radiol, WJR, online ISSN 1949-8470, DOI: 10.4329) is a peer-reviewed open access (OA) academic journal that aims to guide clinical practice and improve diagnostic and therapeutic skills of clinicians.Aim and scope WJR covers topics     

What happens to special hospital patients admitted to medium security?

This article describes the outcome of all the Special Hospital patients admitted to and discharged from the Norvic Clinic over a period of ten years since its opening in 1984. This study identified 23 patients. Of those transferred, 56% had a legal classification of mental illness. A much higher percentage (91%) were restricted under the powers of s.41 of the Mental Health Act 1983, compared to 69% in the West Midlands study (Cope and Ward, 1993). There appears to be a significant difference between the mental disorder groups for age on admission to Special Hospital when considering all patients (males and females). This difference is not maintained when males and females are looked at separately, although the result for males is nearly significant (p = 0.0606). The number of female patients is small (five) and so the tests will hardly be reliable for the female sample. No significant differences were demonstrated for any of the other variables considered. Like the West Midlands study, minor reconvictions were completely absent. This was an unusual finding within the West Midlands study and not replicated from any of the previous Special Hospital studies. In this study, failure constituted an unsuccessful transfer with return to Special Hospital and reconviction. The percentage of those returned to Special Hospital without reaching the community was slightly lower than the West Midlands study, for both the mentally ill and those classified as suffering from psychopathic disorder.     

Introduction to Interventional MRI

An increasing number of interventional procedures are done under imaging guidance. These include biopsies, drainages and injections. Likewise, imaging guidance and monitoring have enabled the use of sophisticated techniques for minimally invasive therapy of tumors. Since MRI provides the best tissue contrast and lesion sensitivity,the use of MR-guided procedures (MRGP) is quickly gaining momentum. Special hardware and software solutions have been developed that allow more efficient interventional use of the MR scanner.This introduction summarizes the basic concepts of interventional MRI and outlines some of the applications of today and tomorrow.     

Regression to the mean. A threat to exercise science?

Regression to the mean (RTM) can bias any investigation where the response to treatment is classified relative to initial values for a given variable without the use of an appropriate control group. The phenomenon and resulting errors of interpretation have been recognised by clinicians in a number of disciplines. The causes of RTM include both intra-individual variance and measurement error. The magnitude of RTM can be estimated quite simply, given a knowledge of intra- and inter-individual variance. RTM can be avoided by using a fully controlled experimental design. Difficulties can also be minimised by making duplicate measurements prior to the experimental manipulation, the first measurement serving for classification, and the second (with randomly distributed variance) allowing an assessment of the response to treatment. Less satisfactorily, surrogate measurements (for example, plasma volume for maximal oxygen intake [VO2(max)]) can assess the bias introduced by an initial non-random sorting of study participants. The impact of RTM on the design and interpretation of investigations has as yet received little consideration by exercise scientists and sports physicians. The response to training is often related to initial measurements of a dependent variable such as heart size, ST segmental depression, fitness or level of physical activity. In particular, analyses of this type have been adduced to support the belief that the response to aerobic training is inversely related to an individual's VO2(max). In fact, RTM may account for a major part of this apparent relationship.     

Is there criteria to allow the selection of patients exposed to asbestos which is relevant to thoracic computed tomography screening?

OBJECTIVE: This study was undertaken to determine whether certain criteria could be used to select among asbestos-exposed subjects those who could benefit from computed tomography screening. MATERIALS AND METHODS: Search for criteria enabling the selection of patients who should undergo a CT screening exam after occupational exposure to asbestos was conducted in 150 subjects. All subjects were explored with selected high-resolution CT scans. Studied parameters were age, exposure data, pulmonary function test results. RESULTS: None of the exposure data or pulmonary function test results suggested with certainty the presence or absence of asbestos-related pleural and parenchymal lung disease. The studied parameters could not be used to select patients who could benefit from CT screening. CONCLUSION: None of the studied parameters enabled a selection of asbestos-exposed subjects who should undergo chest CT screening.     

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Purpose  

To evaluate the effect of the number of readers on the statistical results in peripheral MRA.     

Are RECIST criteria sufficient to assess response to therapy in neuroendocrine tumors?

Material and MethodsWithin the group of 47 patients treated with peptide receptor radionuclide therapy (PRRT), four patients were chosen: three with inoperable tumors without liver metastases and one with two lesions in the pancreas and metastases.ResultsIn all patients, after PRRT, the changes in the sum of the longest diameters of tumors were between ?1% and ?21%, resulting in stable disease reported [strict Response Evaluation Criteria in Solid Tumors (RECIST)]. But the measurements of tumor volume and attenuation in computed tomography and the tumor to nontumor ratio in somatostatin receptor scintigraphy resulted in different response assessments.ConclusionsThe RECIST standard may be not sufficient to properly assess the therapy response in patients with neuroendocrine tumors.     

Science to practice: is t2* enough to assess oxygenation?

As initially reported by Ogawa et al (1), the magnetic resonance (MR) imaging T2* blood oxygen level–dependent (BOLD) signal is sensitive to blood oxygen concentration; however, this signal is also sensitive to a number of other normal and abnormal tissue features. As a result, T2* imaging alone cannot be used to accurately measure vascular oxygenation, much less tissue oxygenation. However, with separate MR imaging measurements of other tissue factors influencing T2*, it might be possible to noninvasively image local tissue oxygen. Such a capability could be of great clinical importance, not only in patients with hypoxic or ischemic disease states, but also in patients with other pathologic conditions that have abnormal respiratory metabolism, such as cancer.     

VO(2) slow component: to model or not to model?

PURPOSE: The purpose of this study was to compare several techniques often used in the literature for measuring the amplitude of the slow component of oxygen uptake kinetics. METHODS: Eight healthy male volunteer cyclists performed two identical bouts of square wave cycle ergometry, from a VO(2) of 60% of the lactic acid threshold (LAT) to 30% of the difference between LAT and VO(2) peak. Predetermined intervals (3--6 and 3--10 min) were chosen to reflect those often used in the literature, namely 3-6 min and 3 min to the end of exercise. Several procedures were used to estimate the 3, 6, and 10-min VO(2) values (20-s averaging, 60-s averaging, and mono-exponential modeling). These were compared with the modeled slow component amplitude using a two-phase model with independent time delays: VO(2)(t) = B VO(2) + A(1)(1 -- e(-(t-TD1)/tau(1)) + A(2)(1 -- e(-(t-TD2)/tau(2)). CONCLUSIONS: The results showed a significant underestimation for all methods of slow component amplitude estimation (P < 0.05) when compared with the actual (modeled) amplitude. In so far as research on oxygen uptake kinetics is used to understand the underlying physiology, it is imperative that the components of the kinetics be determined accurately. The use of a predetermined time frame for estimation of the amplitude of the slow component is not supported by this study. Future investigations should consider these results and make every effort to model the underlying response.