Introduction:

This study primarily examines the comparative efficiency of computed tomography and magnetic resonance imaging with reference to metastatic lung cancer, which denotes an advanced stage of lung cancer in which the cancer has spread from the particular area in the lung where it originated. CT and MRI are both widely-used in the field of lung cancer imaging, which refers to the identification of cancerous masses in lung tissue by means of CT and MRI among other methods of diagnosis.
In terms of lung cancer imaging, radiography is the most widely-used diagnostic tool. Chest radiography is used primarily to establish two aims:
1. The extent of the tumor may be determined through the use of imaging technology.
2. The degree to which the lymph nodes have been affected may also be determined.
This study examines the respective advantages as well as disadvantages of using both CT and MRI. Each is believed to have similar effects to the other, with both being generally viewed as being equally productive. However, this study hypothesizes that CT is more beneficial in lung cancer imaging.
Hypothesis: There will be a significant difference between CT and MRI in the accuracy of diagnosis with CT being better in lung cancer imaging

1. The primary reason for this could be that CT tends to be more universally used because it is less expensive that MRI, and also more readily available.
2. Although CT is more accessible, we will also examine the question of how MRI can identify sulcus tumours because it has multiplanar imaging facilities, which CT does not have.
3. Although normal-sized nodes cannot be identified as metastatic in either CT or MRI, we will examine evidence from emerging studies that CT may be able to provide some assistance in this area.
4. Since approximately 5% of patients with lung cancer have silent metastasis, we will also identify how CT is a valuable diagnostic tool to examine the liver and adrenal glands, which helps rule out that there is metastasis at these locations in the patient’s body.
5. The efficacy of CT will also be examined vis-?-vis other emerging imaging techniques such as Positron emission tomography (PET). It will be established how CT scores above such techniques since many of them are at experimental stages and are also not easily available, or very expensive even if available for implementation.

Aims of the Study:

1. To compare the diagnostic abilities of imaging modalities CT and MRI to detect lung cancer.
2. To discover whether one modality is able to resolve smaller size of metastatic lesions than the other, or detect a greater number of lesions, or detect lesions at particular location / site in the lung, or lesions having a particular appearance.
3. To investigate if there is a significant difference between the diagnostic accuracy of CT and MRI.
4. To find out if screening smokers or ex-smokers for lung cancer can help in management of the disease, and to recommend the same in order to facilitate diagnosis as well as treatment.
5. To find out which Imaging modality is more patient friendly, given the three primary determinants of cost effectiveness, availability and greater accuracy in diagnostic procedures.

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Objectives:

1. To carry out a literature review into the diagnostic potential of CT and MRI to detect lung cancer.
2. To compare the findings for CT and MRI in imaging lung cancer to give an indication of whether one of the modalities is diagnostically superior.
3. Highlight any significant differences and discuss the findings.
4. To draw conclusions and make recommendations for further research and practice.

Methodology:

Three broad criteria have determined the methodology used to gather information for this research project. They are outlined as follows, and the rationale behind the selection (or exclusion) criteria is also briefly outlined.
– Inclusion / exclusion criteria have been determined essentially via date and region, since firstly, rapid developments in healthcare technology indicate that information rapidly becomes obsolete, and therefore the sources used do not date back to more than six years previously. Secondly, the study also focuses primarily on UK-based sources of reference, except in cases where findings are universal or more generally applicable than in most cases. Thirdly, the inclusion/exclusion criteria have also not been based on any specific age/gender/ethnic groups, meaning that no such focus group has been targeted for research. Instead, the study focuses on a cross-section of the demographic statistics that have been determined on the basis of the methods of data collection.
– Methods of data collection: data has been collected primarily through books and print journals published in the U.K. within the last six years (i.e., in the year 2000 or later). Web-based articles that are from authenticated websites (such as university websites, seminar-related findings, websites managed by hospitals or doctors, etc) have been utilized. Also, electronic forms of articles from print journals accessed through such databases as PubMed and Questia have also been made use of for the purposes of collection of data, information, statistics and theoretical findings.
– Ethical approval is a pertinent issue while gathering data for the purposes of such research, since the study deals with a disease that often carries connotations of personal blame because of the prevalence of lung cancer among smokers. Therefore, the researcher has been careful to change (or to not include) the names of patients who have been cited as case studies or as example of particular findings. It has also been ensured that patient anonymity is maintained when citing examples from sources that are secondary.

Literature Review:

Imaging is a useful diagnostic tool in the identification of lung cancer. It has been established that “CT scanning offers greater sensitivity at detecting small lesions” (Burnstein 2000), suggesting that it is a more useful tool than MRI for the identification of cancerous lesions.
This study also recommends that screening should be done to rule out or confirm the possibility. Screening is a practice that seems to have fallen out of favour in recent times in the U.K.:
Screening for lung cancer has fallen into disuse, despite the prevalence of the disease and the known risk factors such as smoking. Randomized trials using either sputum cytology or chest radiography failed to demonstrate survival advantages for chest x-ray screening, although these trials had substantial design problems that have checkered their interpretation. (Burnstein 2000)
Focus group studies have shown, as Burstein’s article observes, that screening has established benefits. It is therefore recommended by this study that screening should be done on a regular and focused basis of potential victims of this disease, which would also aid in early diagnosis and increase the patients’ chances of survival if treated appropriately.
This review of the extant literature on the subject of the efficacy of CT and MRI in the context of the identification of lesions in lung cancer is based on the information, statistics and theory contained in the sources that refers particularly to the following areas of study or concern:
1. Cancer lesions missed by CT.
2. Cancer lesions missed by MRI.
3. Findings of which modality detects most lesions, the locations of the detection if a particular modality discovers a lesion at a particular area in the Lungs, and number and size of the metastasis.
4. Cost Effectiveness of both CT and MRI
5. Which modality is patient friendly
6. If lesions detected in early stages, they can be managed well with treatment.

The articles researched are now presented below, with a brief critical review of each.

Balmes, J. R. and Steinmaus, C. (2000) “Government Laboratory Worker with Lung Cancer: Comparing Risks from Beryllium, Asbestos, and Tobacco Smoke.” Environmental Health Perspectives vol 108, issue 10, pp. 1003-23.
Occupational medicine physicians are frequently asked to establish cancer causation in patients with both workplace and non-workplace exposures. This is especially difficult in cases involving beryllium for which the data on human carcinogenicity are limited and controversial. In this report the authors present the case of a 73-year-old former technician at a government research facility who was recently diagnosed with lung cancer. The patient is a former smoker who has worked with both beryllium and asbestos. He was referred to the University of California, San Francisco, Occupational and Environmental Medicine Clinic at San Francisco General Hospital for an evaluation of whether past workplace exposures may have contributed to his current disease. The goal of this paper is to provide an example of the use of data-based risk estimates to determine causation in patients with multiple exposures. To do this, the authors review the current knowledge of lung cancer risks in former smokers and asbestos workers, and evaluate the controversies surrounding the epidemiologic data linking beryllium and cancer.
Shim, S. (2005). Focal Parenchymal Lung Lesions Showing a Potential of False-Positive and False-Negative Interpretations on Integrated PET/CT. Thorac Cardiovasc Surg 2005;130:1611-1615
Altorki, N.K., et al. (2004). “General Thoracic Surgery: Positron emission tomographic scanning in the diagnosis and staging of non-small cell lung cancer 2 cm in size or less.”
The survey is performed on sixty-four patients of average age sixty-six years who have a mean tumour size of 1.4 cm. it was revealed that the PET should negative results for 45% of the patients. Nodal metastasis was identified in only 17% of the patients. “There was no statistically demonstrable survival difference between positron emission tomography-positive and positron emission tomography-negative tumors (3-year survival of 87% vs 100%, respectively).” The authors conclude that PET scanning “has no demonstrable benefit in the diagnosis, staging, or prognosis of patients with tumors of 2 cm or less in size” over computed tomography.
Henschke, C., McCarthy, P., and Wermick, W. (2002). Lung cancer: Myths, facts, choices-and hope. London and New York: Norton.
An x-ray can reveal a grape-size lump. But a CT scan can find tiny tumors no bigger than a grain of rice. When lung cancer is found and treated early, five-year survival rates soar from a dismal 14% to 70% or even higher. We believe that when the promise of early detection becomes a widespread reality, annual lung cancer deaths could be cut in half. When that happens, the total number of cancer deaths also will drop significantly. Indeed, early detection of lung cancer promises to have a greater impact on the war against cancer than any other single factor on the horizon. (p. 2)
Wolbarst, A. B. (2000). Looking within: How x-Ray, CT, MRI, ultrasound, and other medical images are created, and how they help physicians save lives. Berkeley and London: University of California Press, 2000
Wolbarst’s text is a history of imaging from Roentgen’s time to the current developments in medical imaging. The author is a medical physicist who describes imaging technology as a “revolution” that has taken the medical world by storm, since what is now being carried out by way of diagnostic tools was once believed to be as fantastic as science fiction. The greatest strength of the text is its resourcefulness in terms of correlating theoretical or technological concepts with actual cases, such that the relevance of the technology is lucidly demonstrated through the empirical data or evidence presented by the case studies.
Lardinois, D. (2006). “New horizons in staging for non-small-cell lung cancer.” Journal of Clinical Oncology, Vol 24, No 12 (April 20), 2006: pp. 1785-1787
The optimal strategy for staging should be simple, accurate, noninvasive, and cost effective. Computed tomography (CT) scan of the chest has been considered as the standard modality to assess the intrathoracic spread of NSCLC and is part of the traditional work-up used for staging purpose.
Lardinois goes on to outline the three principal advantages of using CT over other diagnostic tools, which are a critical part of the evidence found by this study which confirms its primary hypothesis. Lardinois cautions that the determination of metastatic disease is very important “since approximately 40% of the patients with newly diagnosed lung cancer present with symptoms as of advanced disease.” He observes that the recommendations set down by the European Respiratory Society require “no additional diagnostic testing in patients without abnormal clinical findings, because the likelihood of metastatic disease is very low in such patients.”
Melling, P., Hatfield, A. C., Peake, M. D., et al. (2002). Lung cancer referral patterns in the former Yorkshire region of the UK. British Journal of Cancer vol 86, 36-42.
This study assesses the impact of the time taken between referral and treatment on the health of the patient, and also allows for some valuable findings regarding the usefulness of CT as well as MRI scans. The authors describe their objective thus:
The purpose of this study was to find out what proportion of patients are referred as lung cancer guidelines assume, whether different referral pathways result in different management and what proportion of patients are seen within recommended time intervals between referral and treatment.
The study conducts a survey of four hundred randomly-chosen records of patients with lung cancer from the archives of the Yorkshire Cancer Registry database. The analysis focuses on case-note analysis, mode of presentation, speciality of initial referral, treatment by specialist, and time intervals for key points in the referral pathways.
It was found that 90.5% of the cases possessed case-notes, of which 47.8% of patients had been referred for treatment on the basis of x-rays. 11.3% of the surveyed cases were self-referred patients who had never been diagnosed by means of imaging or x-rays, or “were referred without a diagnosis of lung cancer by other routes, mainly via GPs.”
Pujol, J-L., Molinier, O., Ebert, W., et al. (2004). CYFRA 21-1 is a prognostic determinant in non-small-cell lung cancer: Results of a meta-analysis in 2063 patients. British Journal of Cancer, vol 90, 2097-2105 (01 Jun 2004).
According to the authors, the “purpose of this study was to determine the prognostic significance of a high pretreatment serum CYFRA 21-1 level (a cytokeratin 19 fragment).” The research was carried out in the context of treatment of non-small-cell lung cancer (NSCLC) as “probably one of the great challenges of medical oncology owing to an increasing incidence in both men and women.” This increasing incidence calls for a greater understanding of the causes and patient management techniques which are related to the disease, as well as of the development and efficient implementation of diagnostic tools that can assist healthcare professionals in such contexts.
Plessen, C. von., Andresen, O., Bremnes, R. M., et al. (2006) Palliative chemotherapy beyond three courses conveys no survival or consistent quality-of-life benefits in advanced non-small-cell lung cancer. British Journal of Cancer 95, 966-973 (23 Oct 2006).
This study assists my research to determine the relationship between the advantages of CT imaging and the efficacy of palliative chemotherapy in the treatment of lung cancer. The earlier the diagnosis, the stronger are the survival rates. Through this trial which was “conducted to establish the optimal duration of palliative chemotherapy in advanced non-small-cell lung cancer (NSCLC).,” the authors compare the effects of diagnostic and treatment procedures related to technological expertise on the quality of life (QoL) and survival rates of patients.
Crispo, A., Brennan, P., Darby, S., Schaffrath-Rosario, A., et al. (2004). The cumulative risk of lung cancer among current, ex- and never-smokers in European men. British Journal of Cancer 91, 1280-1286 (04 Oct 2004)
This article discusses the impact of quitting smoking on the reduction of potential risks of lung cancer, and is based on recent surveys conducted in the U.K. which suggest that “people who stop smoking even well into middle age, avoid most of their subsequent risk” of developing lung cancer. Evidence provided by data collected reveals that in the U.K., “tobacco products, and in particular cigarettes, [are] responsible for most cases of lung cancer.”
The epidemiology of the disease in the U.K. suggests that there are significant similarities as well as disparities with the rest of Europe:
We investigated whether similar absolute risks of lung cancer in men are found in other European countries with different smoking patterns and at different stages of their lung cancer epidemic. Using data for men from a multicentre case-control study of lung cancer in the UK, Germany, Italy and Sweden, and including 6523 lung cancer cases and 9468 controls, we combined odds ratio estimates with estimates of national lung cancer incidence rates to calculate the cumulative risk of lung cancer among men by age 75. Lung cancer cumulative risks by age 75 among continuing smokers were similar for the UK, Germany and Italy at 15.7, 14.3 and 13.8% respectively, whereas the cumulative risk among Swedish male smokers was 6.6%. The proportion of the risk of lung cancer avoided by quitting smoking before the age of 40 was comparable between the four countries, at 80% in Italy and 91% in the UK, Germany and Sweden. Similarly, the proportion of the excess risk avoided by quitting before the age of 50 ranged from 57% in Italy to 69% in Germany. Our results support the important conclusion that for long-term smokers, giving up smoking in middle age avoids most of the subsequent risk of lung cancer, and that lung cancer mortality in European men over the next three decades will be determined by the extent to which current smokers can successfully quit smoking.
Potent inhibition of small-cell lung cancer cell growth by simvastatin reveals selective functions of Ras isoforms in growth factor signaling. Oncogene (2006) vol. 25, pp. 877-887.
The impact of the 3-hydroxy-3methylglutaryl CoA reductase inhibitor simvastatin on human small-cell lung cancer (SCLC) cell growth and survival was investigated. Simvastatin profoundly impaired basal and growth factor-stimulated SCLC cell growth in vitro and induced apoptosis. SCLC cells treated with simvastatin were sensitized to the effects of the chemotherapeutic agent etoposide. Moreover, SCLC tumour growth in vivo was inhibited by simvastatin. These responses correlated with the inhibition of stem cell factor (SCF)-stimulated activation of extracellular signal-regulated kinase (Erk), protein kinase B (PKB) and ribosomal S6 kinase by simvastatin. Constitutive activation of the Erk pathway was sufficient to rescue SCLC cell from the effects of simvastatin. The drug did not directly affect activation of c-Kit or its localization to lipid rafts, but in addition to its ability to block Ras membrane localization, it selectively downregulated H-Ras protein levels at the post-translational level. Downregulation of either H- or K-Ras by RNA interference (RNAi) did not impair Erk activation by growth factors, whereas an RNAi specific for N-Ras inhibited activation of Erk, PKB and SCLC cell growth. Together the collected data demonstrate that inhibiting Ras signalling with simvastatin potently disrupts growth and survival in human SCLC cells.
Didkowska, A., McNeill, A., Powles, J., et al. Lung cancer mortality at ages 35-54 in the European Union: Ecological study of evolving tobacco epidemics.
Examining the percentages pertaining to gender demographics on the prevalence of lung cancer, the authors observe that “Lung cancer epidemics among women show no consistent pattern that follows those in men, either in timing or in relative magnitude.” According to them, this implies that the Lopez model proposed in 1995 is too simple in this respect. For instance, the very high mortality statistics for Hungary indicate that further investigation is necessary.
When attention is focused not on the absolute rates, in men, of diseases caused by smoking but rather on the direction and magnitude of change in younger adults, new E.U. member states from central and eastern Europe are no longer at the bottom of the class. The favourable trends for men would also hold promise for future trends in women if these could be predicted from trends in men. However, these data show that this is unlikely to be the case, emphasising the continuing need for strong antismoking programmes for both sexes.
Peto R, Darby S, Deo H, Silcocks P, Whitley E, Doll R. Smoking, smoking cessation, and lung cancer in the UK since 1950: combination of national statistics with two case-control studies. BMJ 2000;321: 323-9.

For men in early middle age in the United Kingdom the prevalence of smoking halved between 1950 and 1990 but the death rate from lung cancer at ages 35-54 fell even more rapidly, indicating some reduction in the risk among continuing smokers. In contrast, women and older men who were still current smokers in 1990 were more likely than those in 1950 to have been persistent cigarette smokers throughout adult life and so had higher lung cancer rates than current smokers in 1950. The cumulative risk of death from lung cancer by age 75 (in the absence of other causes of death) rose from 6% at 1950 rates to 16% at 1990 rates in male cigarette smokers, and from 1% to 10% in female cigarette smokers. Among both men and women in 1990, however, the former smokers had only a fraction of the lung cancer rate of continuing smokers, and this fraction fell steeply with time since stopping. By 1990 cessation had almost halved the number of lung cancers that would have been expected if the former smokers had continued. For men who stopped at ages 60, 50, 40, and 30 the cumulative risks of lung cancer by age 75 were 10%, 6%, 3%, and 2%.
Lewis, N.R., and Baldwain, D.R. Under utilisation of the 2-week wait initiative for lung cancer by primary care and its effect on the urgent referral pathway. British Journal of Cancer (2005) 93, 905-908.

The findings of this study suggest that this is partly due to continued usage of urgent referral routes outside the 2-week wait scheme and secondly due to a large increase in referrals, probably generated by the introduction of the DoH guidelines. Some adjustment to the guidelines may be appropriate to reflect more emphasis on the early performance of a chest X-ray and the use of direct access to other imaging modalities such as CT. Patients referred outside the 2-week wait are disadvantaged and thus practitioners would be wise to refer all their patients through the 2-week wait system.

Mountain, MD, Libshitz, H.I., and Hermes, K.E. (2002). Lung cancer: A Handbook for Staging, Imaging, and Lymph Node Classification. London and New York: Oxford University Press.
Images pertaining to diagnostic tools are well-represented in this book. See Appendix 1 for pertinent images from this book that have been included to enhance the easy accessibility of the study.
Vansteenkiste J.F.(2002). Imaging in lung cancer: positron emission tomography scan. Eur Respir J 2002; 19:722-742
In the past 5 yrs, positron emission tomography (PET), usually used with 18F-fluoro-2-deoxy-glucose (FDG), has become an important imaging modality in lung cancer patients.
Currently, the use of FDG-PET in respiratory oncology is mainly for diagnosis and staging. Standard indications are the evaluation of an indeterminate solitary pulmonary nodule or mass, where FDG-PET has proven to be significantly more accurate than computed tomography (CT) in the distinction between benign and malignant lesions. Several studies have also convincingly demonstrated that locoregional lymph node staging by FDG-PET (in correlation with CT images) is significantly superior to CT, with a negative predictive value equal or even superior to mediastinoscopy. FDG-PET also improves extrathoracic staging, through the detection of lesions missed at conventional imaging or characterization of lesions that remain equivocal on conventional imaging. Many European countries now have or plan reimbursement in these indications. Large-scale randomized studies should now focus on the impact this accurate tumour imaging technique has on treatment outcome and cost-efficacy.

Hollings, N., Shaw, P. (2002). Diagnostic imaging of lung cancer. Eur Respir J 19: 722-742
Lung cancer, in theory, should lend itself to screening. The disease is very common and in its earliest stages 70% of cases can be cured by surgery 4. Despite this, lung cancer has an overall prognosis so dismal that incidence exceeds prevalence 5. The main risk factor, smoking, is easily identifiable and noninvasive screening tests such as chest radiography and sputum cytology are widely available.
Why is screening not performed? Three large American screening programmes in the 1970s sponsored by the National Institute of Health 6-9 and another in Czechoslovakia in the 1980s 10 screened high-risk populations using chest radiography and sputum analysis. All showed increased detection of early-stage lung cancer, more resectable cancers and improved 5-yr survival rates in the screened versus control groups. Critically, however, none showed a statistically significant reduction in overall mortality.
http://www.massgeneralimaging.org/Chelsea_Site/NewFiles/LungScreening.html
Mass General Imaging Chelsea offers CT scanning as a screening test for lung cancer. “A screening examination is a study performed in order to detect a disease process at a time before signs or symptoms are present. Using sophisticated screening tests, it is hoped that if a disease is present it will be detected at an early stage.”
Preliminary results suggest that Chest CT Screening may lead to early detection of lung cancer in certain populations. Early detection and treatment can significantly improve patients’ survival rate. Five year survival for early lung cancer that has been resected can be 70% or higher. However, you should know that routine screening to detect early lung cancer is not currently recommended by either the American Cancer Society or the National Institute of Health.

CT allows for the enhanced visualization of the lungs and exceeds the capabilities of standard chest x-rays.

In most cases the Chest CT Screening will show the lungs to be normal. However, a variety of lung abnormalities may be detected by CT which would go undetected on chest x-rays. Most abnormalities will be benign, that is, not malignant (cancer) and most do not indicate any serious abnormality or condition. Some of these abnormalities may not require any further examination; others may prompt your physician to order further tests.
If a nodule is detected from a Screening CT scan, it may be necessary for the patient to undergo further testing to determine if such an abnormality is malignant. This evaluation may include follow-up CT studies. The physician will let the patient know if any further testing or evaluation is required after the screening test.

Discussion:

The thesis of this study-that CT is more beneficial than MRI when it comes to the identification of cancerous lung tumours-seems to be supported by various independent studies which confirm that many scientists and medical researchers are also now of this belief. For example, Barclay (2003) observes that CT is better than MRI because “compared with whole-body MRI, the therapy regimen was altered in a substantially larger number of patients when staging analysis was based on the PET/CT data.” This indicates that CT is comparable to PET rather than MRI in its benefits, and that the latter is not as efficacious as the former two methods as a diagnostic tool in the identification of lesions in the lungs.
Secondly, a critical survey of the literature reviewed thus far also indicates that CT is a more effective tool not just for diagnostic reasons, but also in patient management in the post-diagnostic stage. For example, a study of ninety-eight patients in a European hospital determined the following factual findings:
– CT correctly determined the overall tumour stages in 77% of the patients, whereas MRI was correct only in 54% of the cases.
– Because of the CT results, the patient management plans of 12 patients were changed, whereas the MRI results only recommended changes in the treatment plans of two of the patients.
– The critical N-stage was identified correctly in 93% of the cases by CT, and only 79% of the cases with MRI.
While both CT and MRI were approximately balanced when it came to detecting early metastasis, the verification of the T-stage was found to be 80% accurate for CT and only 52% accurate for MRI. (Barclay 2003)
CT is seen to be particularly effective in the identification of early metastasis of lung cancer, especially in the confirmation of the location of secondary lesions, which are particularly hard to identify and can easily be overlooked by other imaging procedures. Such lesions are not often looked for, since they are very uncommonly found. Also, the symptoms resulting from the presence of secondary metastatic lesions are usually atypical, which often results in incorrect or non- diagnosis.
For example, Cappabianca, et al (2002) examine the case of a sixty-nine-year-old woman who had previously been treated for epidermoid lung carcinoma. In her case, her blood cell count showed only a mild case of anaemia, whereas a CT scan (and subsequently as MRI) were used to confirm the presence of two small metastatic lesions that were not indicated by her symptoms. Surgical specimens were subsequently taken to confirm the findings of the imaging procedures. If not for the confirmation of the presence of the lesions by the CT scan, the patient’s case would not have been diagnosed accurately until she had reached a point where emergency surgery would have been inevitable, resulting in conditions that could have proved fatal rather than treatable for the patient. Thus, it is clear that the usefulness of CT in the identification of early developing metastatic lesions is indubitable.
During the course of the research, it may also found to be within the purview of the study to examine the efficacy of CT vis-?-vis that of Positron Emission Tomography (PET). As Schrevens, et al observe in their 2004 article “The Role of PET Scan in Diagnosis, Staging, and Management of Non-Small Cell Lung Cancer,” there is now emerging evidence that PET may be even more effective than CT in the imaging of lung cancer, although this has yet to be proven conclusively. The authors write:
PET has been studied extensively in the evaluation of indeterminate lung lesions. This technique has been accurate in differentiating benign from malignant lesions as small as 1 cm. An overall sensitivity of 96% (range, 83%-100%), specificity of 79% (range, 52%-100%), and accuracy of 91% (range, 86%-100%) can be expected. In the standard situation, semiquantitative image interpretation by measuring the standardized uptake value (SUV) does not improve accuracy compared with simple visual interpretation. In difficult cases, prolonged observation of the metabolic activity of the nodules, measured by SUV, has proven to assist in the differential diagnosis. Early and delayed reading of FDG-PET (dual time-point FDG-PET imaging) shows higher SUV at 3 hours than at 1 hour post-injection for malignant lesions, and the opposite result for benign lesions. (pp. 636)

However, the authors also observe that PET cannot yet replace other conventional forms of imaging, since either the technology is not sufficiently developed yet, or its advantages over other imaging technology have not yet been documented or studied appropriately. This is a channel that can be explored as the study is carried out, and new articles on the subject will be monitored and the literature review updated if more evidence should emerge regarding the superiority of PET to CT or other forms of imaging.

In their meta-analysis of the merits of imaging with reference to lung cancer, Gould, et al (2003), the authors surveyed a selected number of patients who had undergone such diagnostic procedures as CT to find out which was the most accurate. In two out of three areas, CT was found to be the most accurate. These were (a) median sensitivity and specificity, in which CT was found to be 61% accurate, and (b) identification of enlarged lymph nodes, in which CT was found to be less sensitive than PET, but more specific.

While this study does not attempt to construct a historical overview of the treatment of lung cancer in the U.K., it also gathers data and performs assessments based on the viability of conventional testing procedures. In this context, the findings of Peto, et al (2000) in their article in the British Medical Journal (BMJ) titled “Smoking, smoking cessation, and lung cancer in the UK since 1950: combination of national statistics with two case-control studies” provides some essential insights into the history of knowledge concerning lung cancer. The authors debunk some powerful myths about the origins of the disease. While it is indubitable that there is a direct correlation between smoking and the onset of lung cancer in a significant demographic section of the affected patients, Peto, et al observe that when the number of smokers decreased by 50% from 1950 to 1990, the decrease in the incidence of lung cancer among smokers was an even greater percentage, indicating that there is a different angle that should be explored when the statistics are surveyed: that it is not in the number of smokers, but it the number of years that a person has been smoking, that the true roots of lung cancer lie. Such subtleties in the combating of a disease may well be the foundations of discovering the cures for currently terminal illnesses.
As part of its incidental focus, this study also contains a subtext based on the epidemiology of lung cancer in the U.K. A study conducted by Crispo, et al (2004) examines the patterns in smoking in the U.K. when compared to the rest of the E.U. taking a cross-section of the populations in the U.K., Germany, Sweden and Italy, the authors come to the following conclusions:
– Throughout the region, quitting smoking before the age of forty greatly decreased an individual’s chances of contracting lung cancer.
– The cumulative rate of risk for continuing smokers was found to be the greatest in the U.K., in which 15.7% of continuing smokers contract lung cancer by the age of 75.
– The propensity of not contracting lung cancer for those who discontinued smoking by the age of forty was the greatest in the U.K., with 91% of such individuals not contracting the disease.
– The number of future instances of lung cancer in Europe, particularly over the next three decades, would therefore seem primarily incumbent on how many current smokers will give up the habit before or during their middle age.

While this is not overtly stated by the authors, the findings of their study also seem to indicate that there is a greater propensity towards contracting lung cancer for those who continue to smoke beyond the age of forty, suggesting that there may be some correlation between being at this physiological stage and the likelihood of developing lung cancer. This could be an avenue worth exploring for the medical research community.
Another significant issue raised by the literature reviewed has been the so-called ‘waiting period’ between diagnosis and the beginning of treatment, which may be cut down considerably if CT is employed as the primary diagnostic tool, because of its high accuracy and specificity rates. For example, Melling, et al (2004) in their study titled “Lung Cancer Referral Patterns in the Former Yorkshire Region of the U.K.” suggest that different referral methodologies may result in differing diagnoses depending on the period of waiting and the diagnostic procedures implemented. This study indicates the following inferences which could impact the course if the present research:
1. The pre-diagnostic stage should not be overlooked by general practitioners, since their recommendations seem to be the basis of the potential lung cancer victim’s referral for diagnosis and treatment.
2. There should be greater awareness among the general public of the effectiveness of timely self-referral, which, combined with the benefits of diagnostic procedures such as CT, can lead to early diagnosis and increase the patient’s chances of overcoming the disease
It must also be observed at this point that most studies and surveys follow specific methodological procedures. Some surveys are based on hospital records, some on actual patient surveys, and so on. Consequently, results may vary not only on the basis of actual statistics surveyed, but also on the basis of what the respective methodologies have included and excluded. In other words, no research finding can be absolute. I have attempted to examine results from studies based on empirical records rather than theoretical hypotheses or opinions as far as possible, to maintain as great a degree of objectivity and accuracy as it is possible to in such a study, where a vast corpus of hypothetical knowledge exists.
The literature survey has established several empirical ways in which CT seems to have a marked advantage over MRI. For example, Lardinois (2006) has identified some key features of CT which seem to establish that the hypothesis of this study is indeed on the right track. The three key findings regarding CT as established by Lardinois may be outlined as follows:
1. CT provides excellent morphologic information on the extent of disease, but has limited ability to differentiate between benign and malignant lesions in an organ or in lymph nodes.
2. CT has also limited usefulness in the detection of chest wall and mediastinal invasion with a sensitivity and specificity ranging from 50% to 70%, which impairs the evaluation of the resectability of such tumors.
3. Furthermore, several meta-analyses reported low sensitivities and specificities of CT in the assessment of mediastinal lymph-node involvement, ranging from 50% to 65% and from 65% to 85%, respectively. (Lardinois, 2006)
Much of the literature reviewed seems to suggest that CT has a distinct strength when compared to MRI as well as PET in the context of lung cancer imaging. This advantage relates to the high specificity rate of CT, which can identify tumours no bigger than a grain of rice, and is thereby an invaluable tool in imaging procedures which can determine the difference between life and death for a patient diagnosed with this most deadly form of cancer.
In terms of the amount of literature pertinent to the subject, there seem to be an infinite number of authoritarian reports and studies that confirm as well as reject almost every hypothesis that has ever been made about lung cancer. However, one strong sense that one gets from such a literature survey is that there is not enough public or accessible knowledge about this disease. While it is indubitably necessary to have a medical register in which healthcare professionals converse with each other and share their expertise in terms of their experience and findings, it is surprising how little is written for the layperson that presents reliable, accurate information in simple, direct terms. Most layperson’s books on lung cancer are related to the psychological or emotional aspects of the illness, and discuss such issues as the stigma associated with the disease because of its incidence among smokers, or the trauma of dealing with the disease in oneself or in a loved one.
Ironically, not many of such texts that were surveyed for the purposes of this study gave the reader practical and constructive advice on how to deal with lung cancer. If the facts pertaining to the benefits of early detection and the implementation of diagnostic tools such as CT were made more public, more people would screen themselves or attempt to find the right way to go about their treatment. As Lardinois (2006) pints out, his findings indicate that staging procedures should include “a systematic search for distant metastases and [include] a CT scan” so that “potentially operable lung cancer” may be identified and treated accordingly. Most lay people would not even have encountered terms such as “metastasis” in their reading, even those who are highly educated in their own fields, or otherwise very well-informed. Awareness of the potential benefits of CT imaging should not be restricted to the medical community alone, but should be available to lay persons, since they are the ones who form the demographic community that is the basis of such studies.
There certainly needs to be a generation of more awareness about technological innovations in the field of imaging as well as about the essential screening of current or former smokers. The medical community can do its bit to create such awareness by creating a parallel body of literature that is accessible to the general public and which creates the right kind of constructive awareness about this disease, both in terms of prevention and treatment.

In terms of the merits of CT, the literature reviewed has highlighted some seminal advantages that the CT imaging technology has over other conventional forms of diagnosis. For example, Lewis, et al (2005) examine the ways in which CT is superior to such early tools of diagnosis as x-rays. The authors also observe that CT can to some extent counter the demerits of the two-week wait system followed by most medical practitioners. This observation highlights the symbiotic relationship between diagnosis and technology. While technology such as CT is the empirical component of this study, the research is also oriented towards understanding the use of technology in terms of implementation or application in the context of the healthcare culture in the U.K., which uses diagnostic tools in order to make informed diagnoses and patient management programmes. Consequently, it is for this reason, and not for its own sake, that imaging technology needs to be researched and its benefits as well as drawbacks meticulously documented, so that diagnostic and treatment methods may be identified and implemented accordingly. The task of such studies as this, subsequently, is to gather pertinent data on the topic and enrich the existing theoretical or academic database and conceptual framework regarding the various aspects of providing care for patients with lung cancer.

Conclusion:

This review so far has conducted a critical overview of the literature pertinent to the processes involved in CT and MRI imaging diagnostic procedures, and the ways in which they resemble each other, or are disparate from each other. The concluding section assesses the findings of the research, addresses the research questions, and determines further scope for research in the area.

Evaluation of Research

Based on the results generated by this course of research, it was discovered that there are some appreciable similarities as well as disparities between CT and MRI, and that there is substantial evidence suggesting that CT is the more efficacious option for early identification of lesions and diagnosis.
The findings of this review of the comparative literature discussing the two procedures may be summarized as follows, based on the evidence generated during the course of this study:
– Both CT and MRI have been known to determine accurate diagnosis of cancerous lesions in the case of lung cancer, but CT seems to have a greater percentage and frequency of accurate diagnosis. Also, its specificity rate is higher than even PET, which seems to give it a distinct advantage over other processes pertaining to imaging technology.
– From the conducted surveys that were reviewed and assessed, it seems viable that CT is more adept at identifying early metastatic lesions as well, which may occur at a stage prior to that when the symptoms of the disease are exhibited, by which time it is too late to begin life-saving treatment procedures. Thus CT is an efficacious tool in patient management as well as in diagnostic procedures. It may well be life-saving for patients who are diagnosed early.
Given these concerns, the following recommendations have been formulated to encourage further research and thought into the procedures of CT and MRI, as well as of alternative techniques such as PET:
– More research needs to be conducted into the frequency of accurate diagnosis using imaging technology, since this seems to be the only method of providing empirical evidence of the viability and efficacy of diagnostic procedures and of treatments.
– More awareness needs to be created about the positive effects of using imaging technology. Such information is usually restricted to localized surveys that are specific to regions or a small percentage of a particular demographic section, and therefore the results obtained may not accurately present a microcosmic picture of the actual facts.
– Methodologies of research and gathering of data and statistics about the subject should be standardized as far as possible, with every concerned organization functioning with the awareness that its work is part of a larger academic database.
– More studies and surveys need to be conducted by academic institutions, which would provide more statistics on the various cases of people who have benefited or suffered because of the effects of undergoing imaging diagnostic procedures.
– There needs to be a intensified approach to making information about the findings about lung cancer in the medical community accessible to the general public, which should be able to make informed decisions about screening themselves or insisting on being treated with technology that is the most beneficial to them both in terms of diagnosis as well as patient management programmes.

Appendix 1: Images pertaining to diagnostic procedures

Figure 1.1: Computed tomographic scan of the chest (lung windows) http://www.ctsnet.org/book/mountain/IllustratImaging_p9.html
Figure 1.2: Computerized Axial Tomography http://www.massgeneralimaging.org/Chelsea_Site/NewFiles/LungScreening.html
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