Predicting Treatment Response Using Medical Information

Subject:	Healthcare Research
Pages:	15
Words:	4311
Reading time:	19 min
Study level:	College

Abstract

Diagnostic-imaging infers technology-driven medical practice through which the health situation of a patient is investigated by healthcare personnel. Imaging devices are utilized for capturing images through x-raying, scanning and ultra-sounding of internal organs for onward medical prediction, interpretation or diagnostics. Due to the constant emergence of dieses or complexity of existent ones, medical imaging has transformed through the years to meet up with the transitional demands of emergent and occurring modalities in a format that is structural.

Through the sophistication of imagining tech, it is possible to transfer patients’ demographics, examination-properties, imageries, or numerical-data in secured and highly efficient ways. Much of the credit to medical imaging predictions addresses cancerous diseases. Studies have shown that at least twenty-five percent of patients with a tumor that is bigger than three centimeters have benefited from neoadjunctive chemotherapy which is highly dependent on predictions using medical imaging. This study is concerned with predicting treatment response using medical imaging information.

Background

Much of the credit to medical imaging predictions addresses cancerous diseases. Studies have shown that at least twenty-five percent of patients with a tumor that is bigger than three centimeters have benefited from neoadjunctive chemotherapy which is highly dependent on predictions using medical imaging (Buchegger et. al, 2000). It is further noted from studies that:

“It is estimated that up to 25% of [cancerous] patients do not respond to this chemotherapy2, therefore it would be beneficial to predict which patients do not respond positively to this chemotherapy” (Landheer et. al., 2001).

A tool that aids in predictions using medical imaging has been noted to include:

“Methods to detect the response of a breast cancer tumor to neoadjunctive chemotherapy [which make] use of positron emission tomography (pet) scans” (Geoghegan and Scheele, 1999).

The reliability of medical imagining is functional of artificial intelligence through articulate structuring of models which are precedent on earlier investigations of a particular circumstance in algorithm formats that could be fed with finite collections of observations. This paper will present studies on predicting treatment response using medical imaging information with specified inclination to algorithms –of-data-acquired through clear data analyses.

In there research, Glover et. al.,(2000) studied an optimal time for medical-imaging utilizing the pet device for prediction of patients’ response to neoadjunctive-chemotherapy. The study was effective in its measurement of mean standards for up-taking midpoint-neoadjunctive values in chemotherapy which reflected an approximately seventy-seven percent low-patients response, and a hundred percent high response which achieved a 93% area roc. The paper will adopt similar analytical approaches in its presentation of the subject mater.

Introduction to Cancer, Colorectal Cancer & Liver Metastases

Studies have reviewed that the presence of metastatic-disease which is found within the liver is recurrent in oncology (Primrose, 2002). Epithelial cancer finds the liver a very good site for growth where it spreads metastatic-natured, only seconding the lymph-nodal region. In any case, research has not proven adequately the prevalence of the disease. For instance, Curley et. al., augurs inline with this as follows:

The true prevalence of metastatic disease is unknown, but approximately 20%–25% of patients with colorectal cancer have liver metastases at the time of diagnosis. Studies based on autopsy results showed that up to 70% of colon cancer patients have liver metastases at autopsy (Curley et. al., 1999).

This complexity has made the adaptation of medical imaging very vital in predicting the development of colorectal cancer. When the prediction turns positive and there is an early diagnosis of the liver-metastases, this could go a long way to be of great help to a cancerous patient. It has been noted generally that:

“The presence of liver metastases indicates non-resectability of the primary tumour for oncologic reasons, except for tumour palliation (i.e. to relieve obstruction of the gastrointestinal tract)” (Bloom et. al., 1999).

Considering patients with this condition, using the method of chemotherapy has always been a preferred option. Only with a certain number of malignancies, re-sectioning the liver’s metastases would then indicate an improvement of chances for the patient’s survival (Johns and Houlston, 2001). Studies have stressed that:

Colorectal cancer is one of a few malignant tumours in which the presence of limited synchronous liver metastases (i.e. occurring at the time of diagnosis of the primary tumour) or metachronous metastases (occurring after diagnosis of the primary tumour) warrants surgical resection (Zealley et. at., 2001).

Kemeny and Fata further noted that:

“Exact knowledge of the number, size, and regional distribution of metastases is essential to determine their respectability” (Kemeny and Fata, 2001).

The perdition of treatment on a patient at this instance would depend on the localization/number of the liver-metastases and there would be a consideration of the several clinical-parameters that relates to the patient. The chances for resectioning colorectal-patients with liver-metastases stand at 30% (Heslin et. al., 2001). In any case, the possibility for the patients to survive in five years is just about 30% to 48% as compared to the five-percent of chances for survival for patients with liver-metastases which is not liver-surgery amenable (Popov et. al., 2002).

It is the responsibility of radiologic-imaging to analyze the condition of the liver by assessing the availability or the non-availability of liver-metastases when considering surgery of better predictions as well as for evaluating successes of other patients’ chemotherapy. even though there has been the use of transabdominal-sonography in assessing the liver, the method is not without its shortcomings: there has to be a consideration of the operator’s level of understanding which in most cases reflects the reviewer of equivocal-results in patients who (induced with chemotherapy) express fatty liver infiltrations.

According to Cromheecke et al:

“These problem cases are then often referred for a computed tomography (CT) or magnetic resonance (MR) imaging examination” (Cromheecke et. al., 1999).

Presently when the Multidector-CT (MDCT) imaging-device has been introduced, using ct for screening of patients’ lungs, liver, or lymph-node in oncology has become rather dramatic and on the increase. MR-imaging has continued to have defined point of reach through anatomic-coverage; even though the freshly introduced multi-channel according to Muller:

“ coils with wider coverage and the moving-table MR technique has re-established the ‘competitiveness’ of MR with MDCT with regard to patient throughput” (Muller, 2000).

A particular merit that is known of the MR liver-imaging is the fact that is effects the softening of tissue-contrasts thereby revealing more acceptable characterization of focal-liver-lesions which may be considered. Studies have viewed that:

“The development of a liver-specific MR contrast agent has further improved the diagnostic yield of MRI in lesion detection and characterization” (Abramson et. al., 2000).

The revolution identifies MR-imaging’ key-role which is no specifically gadolinium-chelates as well as specific liver MR contrasting agent has been itemized. The CT/MR imaging context of liver-metastases is identified. For a more defined prediction from the use of this medical imaging device, there is emphasis on the key-role which the MRI presents when compared with ct for assessing the condition of patients with the extraheptic-cancer condition as well as limited-liver-metastases-this is considered when the patients are candidates for surgical operations.

Equally, in the area of the use of ultrasound, studies have noted that:

“The development of ultrasound (US) contrast agents (SonoVue, Bracco, Milan, Italy; Levovist, Schering, Germany, etc.) has dramatically increased the potential of sonography in the assessment of focal liver lesions” (Liu et. al., 1999).

Using contrasting agents, according to Kemeny and Fata:

“…makes perfusion mapping of focal lesions a lot easier thereby enabling characterization of focal lesions” (Kemeny and Fata, 1999).

Studies conducted by Li et al,(1999) reviewed usage of enhanced contrast us (CEUS) for improving the sensitiveness or the US specific usage through differentiating malignant-vs-benign at about 78%-100% from 23%-92%, respectively. Equally, Okuno et al., (1999) studied diagnostic-yield of CEUS and helical-ct for predicting liver-metastases and noted a CEUS of 97% when lesions was observed using CT. in any case, the studies did not reveal any histological-standards for referencing availably determined sensitivity.

Presently, CUES presents a clearly defined role in evaluating and predicting equivocal-lesions in the US-convention and in the monitor of reaction to treatment after there has been a localized tumour-therapy. But based on the shortcomings witnessed in visualizing sectional distributions of 3D-shaped metastases, there has been the limitation in pre-operating the patient assessment using colorectal-liver-metastases. In any case, contrasting agents have brought about an increment in diagnostic-yield of intraoperative-US which impacts on strategic surgery.

Another fantastic tool for predicting treatment responses of patients has to do with multidetector-row-CT (MDCT) and helical which have been very useful imaging-modeling. The device has the advantage of:

“Using a helical CT with a single detector row and a scanning speed of 0.8–1 s per rotation” (Neeleman et al., 2001).

In any case, it has been noted from studies that:

“…it is impossible to scan the entire liver in a truly arterial phase, before contrast material inflow from the portal vein is encountered” (Ruers et al., 2001).

There was an Introduction of a 4-row detector scanning system in the year 1998. The device has been very effective in covering the liver in the briefest ten to fourteen seconds, and feasibly reduces the possibility of motion-artifacts which could affect the scanning process while the patient is breathing. Presently, the forty to sixty-four row-MDCT scanning device has a 0.6mm detector device configured to it which presents a highly precise definition of the condition of the patient, and is of outmost value to predicting the response of the patient to treatment. Equally, the device has enabled a reduced rotation-time to 0.33 seconds at most! This has been enabling liver scanning using submillimeter-collimation within the briefest two or three seconds of breathhold. Dependent on isotropic-voxels, reforming images through whatsoever plane is realizable without any loss of spatial resolutions.

A number of researches have been carried out on assessing the usage value of thin-slices in order to bring about an improvement in detecting small-metastases- these studies can be relevant to predicting treatment responses as well in patients. For example, Fong et. al.,(1999) conducted studies on slices and noted that:

“2.5 mm thick slices were significantly superior to 5, 7.5 and 10 mm thick slices” (Fong et. al., 1999)

Equally, studies conducted by Liu et. al., revealed:

“A slice thickness of 3.75 mm proved superior to 5 mm in terms of lesion characterization and superior to 7.5 mm in terms of detection and characterization”( Liu et. al., 1998).

In the situation whereby the slices are less than 1mm in thickness, there would be no significantly noticed lesion improvements- in exception, the situation is otherwise if there is a significant increment in image-noise which has subsequent image-quality degradation. Slices that are within the range of two and four millimeter are very appropriate for axial-viewings and considerably better enhancers for prediction of patients responses to treatment. Little wonder then that studies conducted by Huang et. al., (2002) reviewed significant imaging-protocol variations in small liver-lesions at less or,

“In addition to those 2–4 mm thick slices obtained for viewing, submillimetre slices are obtained for 3D-image reconstructions” (Huang et. al., 2002).

Presently, there is the debate on the number of scans which could be carried out for examining the liver using ct. these arguments make the position of predicting treatment responses of patients from consideration of the Argument a bit undefined. But on the general note, studies have reviewed that:

“The value of an unenhanced scan lies primarily in the characterization of small lesions as being solid or cystic” (Machi, 2001).

However, patient with colorectal-cancer, liver-metastases are eleven percent calcified during the fist presentations (Ruers, et. al., 2000). It is easier to analyze the lesions using unaided scans as compared to using portal-venous-phase scans which rather make prediction of responses to treatment of a patient complicated. There could be the preference by adopting the usage of arterial-phase-scans which have vast value in diagnosing hypervascular-metastases as well as in differencing haemangiomas from lesions. The increment in the seasonal MDT-resolution fascinated a number of researchers towards adding earlier arterial-phase along with their protocols that has been of high use in HCC patients. This according to Bilchik et. al., (2001) is due to the fact that:

“Colorectal liver metastases are hypovascular in the vast majority, but arterial-phase scans may increase lesion conspicuity in a small number of cases” (Bilchik et. al., 2001).

Portal-venous-phase scans have demonstrated high reliability in making available highly supportive information for predicting the response to treatment of a patient and in detecting the level of colorectal-liver-metastases whereby there is 85.10% helical-sensitivity Bilchik et. al.,(2001).

Dynamic Contrast-Enhanced MRI

This particular modality of perfusion-imaging makes use of repetition of imaging in tracking the emergence of contrasting agents that are diffused into body tissues within a period of time. Acceding to studies, this is achieved when:

“…a paramagnetic contrast agent, gadolinium-DTPA, is injected intravenously circulates through the body and diffuses over time into the extravascular extracellular space. As the mean contrast agent concentration within a voxel increases, the signal intensity from that voxel increases” (Choi et. al., 2001).

Through the knowledge of the characteristics of sequences of imaging, there is the possibility of converting relative-signal-increases into a quantifiable or measured contrasting-agent after a period of time. Analogical curves can then be made use of in obtaining semi-quantitative analogs that would clearly identify the path of flow of blood and can be appropriately used for predicting the rate or level at which the patient is responding to treatment (Lorenz et. al., 1998). Equally, in a situation whereby a related concentration-curve is realized from arterial-blood, collective data could be used for a compartment-kinetic-theory-of-Kety in realizing a better quantified index of the flow of blood as well as have a comprehensive knowledge of capillary permeably.

Imaging-Based Clinical Trials

Clinical trials have a very fundamental placement in testing a newly produced drug or a device in present-day medical practices. Medical-imaging recently has assumed so much significance in clinical-trials due to the fact that images make available highly precise pictorial definition of a diagnosed condition in quantifiable parameters. According to studies:

A typical imaging-based clinical trial consists of:

A well-defined rigorous clinical trial protocol,
a radiology core that has a quality control mechanism, a biostatistics component, and a server for storing and distributing data and analysis results; and
many field sites that generate and send image studies to the radiology core (Gillams and Lees, 2000).

With the general increment witnessed in clinical trials, there is an equally associated difficulty with the service of fundamentals of radiology in serving adequately as administrative or distributive mechanism for participatory clinician/radiologists at the global screen.

From studies, it has been gathered that:

With ever-increasing number of clinical trials, it is a great challenge for a radiology core which handles multiple clinical trials to have a robust server to administrate multiple trials as well as satisfy the requirements to quickly distribute information to participating radiologists/clinicians worldwide to assess trials’ results. Data Grid in the grid computing technology can satisfy the aforementioned requirements of imaging-based clinical trials (Dancey et. al., 2000).

The Data-Grid-testbed mentioned from the study where sectionalized into three sites which are internal, as noted:

“Image Processing and Informatics (IPI) Laboratory at University of Southern California, USA; the Hong Kong Polytechnic University; and InCor (Heart Institute) at Sao Paulo, Brazil” (Link et. al., 2001).

This was aided by the availability of supersonic networking systems such as the HARNET, and RNP2-which further demonstrated the application of technology in realizing better healthcare services (Fiorentini et. al., 2000). The general benefit of this data-grid includes:

“an understanding of the methodology for using data grid technology and high speed networks in clinical trails;
“an establishment of the performance benchmarks of Data Grid over high speed networks; and
a Data Grid test bed for performing worldwide imaging based clinical trials” (Stubbs et. al., 2001).

This is also a functional tool for an enhanced patient-treatment-response prediction.

Regression

The occurrence of atherosclerosis is known to take place in the vessels of that heart as well as in the carotid or neck in persons who are grown up, most frequently. Usually, the situation is known to be associated with individuals who how have much concentration of cholesterol. An individual with this kind of situation would be treated using a cholesterol reducing agents (such as statins) and would be required to have a modified diet as well as be constantly engaged in exercise (Lode et. al., 1998). Presently, there is ongoing studies on fresh ways witch have to do with the use of magnetic-resonance-imaging (or MRI) as well as employing the use of computer demographic imaging in detecting flow-blockages in blood vessels which can not be tracked form a mare consideration of cholesterol-level as well as from risk-factors for heart-diseases (Wagner et. al., 1984).

The progression is effective to predictive based on:

“…measure of atherosclerosis in the heart vessels and carotid arteries using imaging tests (computed tomography (CT) and magnetic resonance imaging (MRI)) before and after standard treatment with cholesterol lowering medication [statins] (Goldberg, 2001).

The technology is eligible for healthy persons who are not less than fifty-five years and are patients considered for therapy in reducing their blood-cholesterol-levels. It is designed to actualize the following:

“This study will involve one screening visit and seven study visits over a period of 2 years.
“Participants will be screened with a physical examination and medical history, as well as blood samples and tests to ensure that it is safe for them to have CT and MRI scans. Participants will provide information on current medications, dietary habits, smoking status, alcohol and caffeine intake, and their level of physical activity.
“Participants will be divided into two groups. One group will receive standard doses of medication to lower cholesterol according to current treatment guidelines, while the other group will have MRI scans of the carotid arteries and a CT scan of the heart to determine the best medication dose levels.
“Visits 3 to 5 will be scheduled 3, 6, and 9 months after visit 2. During these visits, researchers will monitor for possible side effects and may change or adjust medications and doses.
“At visit 6, participants will have an MRI scan of the carotid arteries, a physical examination, and blood tests. Medications may be changed or adjusted.
“At visit 7, participants will have blood tests, and medications may be changed or adjusted.
At the final visit, participants will have MRI and CT scans of the carotid arteries and heart, respectively, as well as a final physical examination and blood tests” (Ruers and Bleichrodt, 2001).

Univariate Linear Regression

A study was conducted on colorectal-liver-metastases treatment with preoperative-chemotherapy and indicated incensement in progression free-survival. According to Parikh et. al., (2002),

“Given the survival benefit of bevacizumab in metastatic CRC, the aim of this study was to assess the efficacy and safety of bevacizumab based chemotherapy in the perioperative setting. In this single arm prospective pilot study, patients with resectable LM eligible to receive perioperative BV and chemotherapy were included. Kaplan Meier survival analysis was used to calculate overall survival and progression free survival” (Parikh et. al., 2002).

Multivariate Linear Regression

It is the responsibility of radiologic-imaging to analyze the condition of the liver by assessing the availability or the non-availability of liver-metastases when considering surgery of better predictions as well as for evaluating successes of other patients’ chemotherapy even though there has been the use of transabdominal-sonography in assessing the liver, the method is not without its shortcomings: there has to be a consideration of the operator’s level of understanding which in most cases reflects the reviewer of equivocal-results in patients who (induced with chemotherapy) express fatty liver infiltrations (Copur et. al., 2001).

Errors In Variables Regression

The CT/MR imaging context of liver-metastases is identified. for a more defined prediction from the use of this medical imaging device, there is emphasis on the key-role which the MRI presents when compared with CT for assessing the condition of patients with the extraheptic-cancer condition as well as limited-liver-metastases-this is considered when the patients are candidates for surgical operations (van Riel et. al., 2000).

Nonlinear Methods (Trees, Random Forests, Neural Networks, Support Vector Regression)

It is the responsibility of radiologic-imaging to analyze the condition of the liver by assessing the availability or the non-availability of liver-metastases when considering surgery of better predictions as well as for evaluating successes of other patients’ chemotherapy even though there has been the use of transabdominal-sonography in assessing the liver, the method is not without its shortcomings: there has to be a consideration of the operator’s level of understanding which in most cases reflects the reviewer of equivocal-results in patients who (induced with chemotherapy) express fatty liver infiltrations.

CRC Liver Met & Bevacizumab Study

The CRC presents a clearly defined role in evaluating and predicting equivocal-lesions in the US-convention and in the monitor of reaction to treatment after there has been a localized tumour-therapy. But based on the shortcomings witnessed in visualizing sectional distributions of 3D-shaped metastases, there has been the limitation in pre-operating the patient assessment using colorectal-liver-metastases.

Patients & Study Design

For a more defined prediction from the use of medical imaging devices, there is emphasis on the key-role which the MRI presents when compared with ct for assessing the condition of patients with the extraheptic-cancer condition as well as limited-liver-metastases-this is considered when the patients are candidates for surgical operations.

Imaging Method

Basically, medical-imaging is carried out using x-raying, ultra-sounding, magnetic-resonance as well as radionuclide. Each of this has an edge over another in a way-for example, through displaying anatomical structures in a way that would show the physiological activities of the organ/tissues. This basic methods and a number of other are discussed below:

Computed Tomography

This is the highest for of definition of medical-imaging which creates the cross-sectional view of an organ. According to Ragnhammar et. al., (2001),

“…an imaging procedure that is repeated many times to obtain a complete image or a set of images of a region of the body is commonly referred to as a scan” (Ragnhammar et. al., 2001).

It has also been noted that:

This method uses narrow beams of x-rays that are recorded by an array of detectors around the body. CT is used to produce images of muscles and connective tissues, and organs (liver, kidney, spleen, pancreas, bladder, adrenal glands, prostate gland, and lymph nodes). CT is extremely useful in examine the brain to detect damage or deterioration as well as the size and location of a tumor. Three-dimensional images of bones can be generated by CT and used in planning reconstructive orthopedic surgery;

Fluoroscope: this is a method that uses X-ray projected onto a TV-like monitor so that the body parts and motion are seen in details. For example, the beating on the heart can be captured under this circumstance and analyzed. A number of fluoroscopic examinations do need contrast dyes to highlight a particular area of the body;
Magnetic Resonance Imaging (MRI): this is a method that uses a magnetic field and pulses of radio wave energy in making an image of organs and structures inside the body. At several instances, MRI brings about different information from a structure in the body than could be seen with an X-ray, an ultrasound or a computed tomography scan. MRI may also identify problems that cannot be seen with other imaging methods. MRI is very useful in evaluating diseases of the brain and spine, and presents the extent of damage caused by stroke and the condition of the spine following surgery. It is equally relevant in the examination of joints and abnormalities in muscle and connective tissues, tumor and blood vessel diseases or infection. During the MRI test, the part of the body being studied is placed inside a special machine that contains a strong magnet;
X-ray radiography: this method is used to bring about film x-rays. It is the most commonly use method of medical imaging. Images obtained are typically used for examination of the lungs, bone fractures, and teeth, and to deselect ulcers, kidney stones, as well as cancer;
Ultrasonography or Ultrasound Imaging: this method makes use of a high-frequency sound wave to produce images. Utrasonography is basically made use of in heart related organs and in the abdomen for the evaluation of a fetus (Popov et. al., 2002).

And then there is radioisotope imaging which uses radioactive emissions for definition of a condition. On the general note, these tools have become the life-blood of medicine and are effective in predicting, diagnosing, as well as in treating malfunction of body parts in patients (Hasuike et. al., 2002).

Summary Statistics

In there research, mcdermott studied an optimal time for medical-imaging utilizing the pet device for prediction of patients’ respones to neoadjunctive-chemotherapy. The study was effective in its measurement of mean standards for up-taking midpoint-neoadjunctive values in chemotherapy which reflected an approximately seventy-seven percent low-patients response, and a hundred percent high response which achieved a 93% area roc. The paper has adopt similar analytical approaches in its presentation of the subject mater.

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