16 of the greatest questions ever asked on Yahoo! Answers
Choosing between Ct scan vs MRI is totally depended upon the This may be dangerous for those suffering from liver or kidney disorders. Theoregonartist is referring to an MRI, which is different from a CT scan. A CT scanner is basically a big rotating X-ray machine. By taking. Scanning a mirror doesn't work. Source: Serious question. Source: More: 8 brilliantly bizarre questions asked on Yahoo! .. TOP CAT 4y.
March 28, ; Accepted Date: June 08, ; Published Date: June 12, Citation: J Nucl Med Radiat Ther 6: This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The radiation dose and gestational ages during X-rays is the yard stick for measuring whether it will have an effect on the embryo or foetus at the time of exposure.
During X-rays, high dose of ionizing radiation on embryo or foetus may causes some effects such as miscarriage, restriction of fetal growth, congenital malformation which include microcephalyor lead to mental retardation sometimes can cause cancer during childhood.
Therefore, it is recommended that during pregnancy or developmental stages X-rays of high dose is not advisable. Keywords X-ray; Electromagnetic radiation; Embryo; Foetus; Miscarriage; Congenital malformation; Microcephaly Introduction X-rays belong to a group of radiation known as electromagnetic radiation.
- Pancreatic Cancer Imaging: The New Role of Endoscopic Ultrasound
- The Effects of X-rays (Radiation) on Embryonic and Fetal during Developmental Pregnancy Stages
- Ct Scan Vs MRI, Important things to know for a patient
It propagated in form of waves and made up of electric and magnetic field that are mutually supported each other. It is produced by a charged particles being accelerated and emit electromagnetic radiation and propagated without any medium [ 1 ]. X-rays is the powerful invisible rays sending to an examine body that can pass through it to see its inside, such as human body, metals, baggage and created an image where is usually used for medical purposes in human, for identification of fractures in metals and for investigation of hidden items in baggage [ 2 ].
However, after this first step, there is a place for EUS as a second diagnostic level in several cases: In the near future, there will be great opportunities for the development of diagnostic and therapeutic EUS and pancreatic cancer could be the best testing ground. Pancreatic cancer is a major health problem for several reasons: Unfortunately most patients present late in the course of their disease with advanced cancer either locally or with metastatic spread [ 23 ].
Are CT scans every three months necessary when NED but doing adjuvant treatment with Yervoy (trial)
Furthermore if we consider the high cost of major pancreatic surgery, not only in terms of money but also in terms of morbidity and mortality even in the most experienced surgical hands [ 1011 ], it is clear that all our efforts must be oriented towards the need for an early diagnosis and towards reliably identifying patients who really can benefit from major surgical intervention. A recent study [ 12 ] indeed found that we could achieve a complete resection with negative margins in almost half of 53 patients with suspicion of locoregional pancreatic cancer when state-ofthe- art preoperative imaging is used.
Pancreatic tumors have always represented a complex dilemma for clinicians and diagnostic imaging and, currently, there is no consensus on the optimal preoperative imaging modality for diagnosis and staging assessment of patients with suspected or proven locoregional pancreatic cancer.
Over the years, this has led to a complex range of diagnostic proposals which are summarized in Figure 1. Nevertheless, sometimes we need all the same cytological and histological confirmation. The complex range of proposals and possibilities for the diagnosis and staging of pancreatic cancer. Modern imaging techniques such as transabdominal ultrasound UScomputed tomography CTmagnetic resonance imaging MRI and endoscopic ultrasound EUS are less invasive and less costly than surgery.
For years, EUS has been considered to be the best available technique for imaging the pancreas but, in the last ten years, we have witnessed notable technological improvements of the radiological and nuclear imaging techniques which have arrived in rapid succession.
Taking into account the rapid increase in the sensitivity and accuracy of these new technologies, we will try to delineate the new role of EUS in pancreatic tumors imaging and to place EUS in a shareable diagnostic and staging algorithm. The Challenge of EUS EUS has been one of the most important innovations which have occurred in gastrointestinal endoscopy during the last 25 years. It has extended the range of possibilities for endoscopic diagnosis, supplying the endoscopist with the unequalled opportunity of seeing not only the mucosal surface but within and beyond the wall of the gastrointestinal tract Figure 2.
The challenge of EUS: For many years, it was a mere imaging modality, but the development of new electronic instruments with linear or sector scanners allowed the visualization in the echographic field of a needle emerging from the operative channel of the echoendoscope thus guiding the needle in the target lesion both within and outside the gastrointestinal wall.
For many years, EUS has been advocated as the best available technique for imaging the pancreas.
High resolution images of the main pancreatic duct and surrounding parenchyma can be achieved, and structures as small as 2- 3 mm can be distinguished due to the small distance between the transducer and the gland which allows the use of higher frequency probes, from 7.
Given the increasing sensitivity of MDHCT and the high cost of MRI, magnetic resonance imaging to date should not be considered the first choice in pancreatic cancer diagnosis and staging even though MRI may be useful in the detection and characterization of non-contourdeforming pancreatic masses, more sensitive than CT in the detection and characterization of small liver metastases and peritoneal and omental metastases [ 1623 ]. EUS allows high resolution images of the pancreatic parenchyma with both mechanical a and electronic b scanners.
In contrast to the very high sensitivity previously shown, the specificity of EUS is limited, especially when inflammatory changes are present. EUS-FNA may overcome some of the specificity problems encountered with EUS in distinguishing benign from malignant lesions, allowing an improvement of EUS accuracy, mainly as a result of enhanced specificity, without sacrificing too much in terms of sensitivity [ 28 ].
Ct Scan Vs MRI, Important things to know for a patient
In short, the development of modern imaging modalities has limited or almost annulled the advantage of EUS in terms of sensitivity, accuracy for T and N staging and prediction of resectability i. Multiple published studies [ 12293031323334 ] with discordant results have compared EUS and CT or other imaging modalities used in detecting or diagnosing, staging and prediction of resectability of suspected or known pancreatic cancer.
For example, in the study of Schwarz et al. For small tumors the most sensitive method remains EUS which correctly predicted all lesions less than 2 cm.
When comparing accuracy rates for resectability, EUS was the leading modality, but the variance when compared with spiral CT was not significant. In a recent systematic review of DeWitt et al.
There are many methodological limitations which potentially affect validity. Overall, EUS is superior to CT for detecting pancreatic cancer, for T staging and for vascular invasion of the splenoportal confluence. The two tests appear to be equivalent for N staging, overall vascular invasion and assessment of resectability. The optimal preoperative imaging modality for the staging and assessment of resectability of pancreatic cancer remains undetermined.
Prospective studies with state-of-the-art imaging are needed to further evaluate the role of EUS and CT in pancreatic cancer. Furthermore, we should refrain from the idea that investigations only exist to compete with one another, but, instead, accept that different technologies often provide complementary information which ultimately results in optimal patient care. An overriding principle of care should be that patients should first undergo the least invasive, least harmful and most widely available examination [ 36 ].
Moreover, we must consider the fact that EUS can not identify distant metastases, is still not universally available and is, to a high degree, operator dependent. Current Role of EUS in Pancreatic Cancer Diagnosis Starting from the above-mentioned concepts, we will propose a diagnostic algorithm in the case of suspected pancreatic cancer, trying to place EUS in shareable and evidence-based positions inside this algorithm.
It is summarized in Figure 4. In this chapter, we will discuss some clinical scenarios in order to better understand the diagnostic algorithm. As we have already mentioned, in the case of clinical suspicion of pancreatic cancer, the initial study of choice should be a spiral or multidetector CT; if there is a pancreatic cancer with distant hepatic for instance metastases, there is no place for EUS in this clinical setting.
If pancreatic EUS is negative, you can reasonably exclude pancreatic disease. A proposal of a diagnostic algorithm for patients with suspected pancreatic cancer.
Can a single head CT scan cause cancer?
In the second scenario, the CT scan shows some doubtful pancreatic changes or inconclusive imaging such as small less than 2 cm masses, fullness, enlargement or prominence of the gland.
The clinical significance of these indeterminate CT findings has not been established; however, in a clinical setting with a suspicion of pancreatic cancer, they are very worrisome. In this case, EUS is also indicated and again we can rely on its high negative predictive value [ 38 ], with the possibility of real-time EUSguided FNA which has been demonstrated to be useful for overcoming EUS specificity problems in the differential diagnosis between malignancy and inflammation [ 2838 ].
In the third scenario, CT imaging is positive for pancreatic cancer. Contrast-enhanced MDHCT is highly accurate for the assessment of pancreatic cancer staging and resectability [ 39 ]. If the tumor is deemed resectable, the patient can go straight to surgery, even if some authors, in order to reliably identify patients who might really benefit from major surgical intervention, recommend EUS to be performed as a second staging modality [ 1640 ].
If both methods confirm resectability, the patient is referred to the surgeon and there is general agreement between experts and the literature that FNA is not necessary for resectable cancers.
Moreover, in some cases, one can argue that not all pancreatic tumors are ductal adenocarcinomas: In this case, if there is any imaging or clinical doubt about the nature of the mass, FNA may be advisable even in the presence of a resectable pancreatic mass [ 1641 ].
On the other hand, if MDHCT shows a non-resectable pancreatic tumor, histological or cytopathological confirmation is needed in order to guide the patient to protocols of palliative radio- or chemotherapy [ 1642 ]. The authors suggest that, if a high clinical suspicion of pancreatic cancer persists after a negative EUS, a repeated examination after 2- 3 months may be useful for detecting an occult pancreatic neoplasm. There is only one answer to this question, namely when the information obtained can change patient management.
Pancreatic Cancer Imaging: The New Role of Endoscopic Ultrasound | Insight Medical Publishing
Therefore, we need cytopathological confirmation: The differentiation of a malignant from an inflammatory tumor, especially in a setting of chronic pancreatitis, is very challenging.
This is one of the main limitations of EUS, which is also observed with all other imaging modalities. It restricts the value of EUS in one of the most frequent differential diagnostic dilemmas in pancreatic diseases.
In this case, histological confirmation may be of outstanding value, and EUS-FNA also showed some limitations in the presence of chronic pancreatitis, in particular, a lower sensitivity in comparison to patients without chronic inflammation The authors suggest some tips for improving the yield of pancreatic mass EUS-guided FNA in the setting of chronic pancreatitis: Another new tool which, in the near future, could be useful in this setting is EUS elastography [ 48 ].
Allowing the visualization of tissue elasticity distribution, it may help in the differential diagnosis of focal pancreatic masses or in the differentiation of benign and malignant lymph nodes or various solid tumors.
MRI, magnetic resonance imaging, however, uses magnetic fields and radio frequencies to do the same. The difference in the techniques becomes the biggest factor when choosing a particular scan and one or the other is suggested by the doctor depending on the scan requirements. What is a CT Scan? This is a combination of a series of x-ray images taken at different angles. The scan uses a computer program to generate a complete image based on these x-rays.
This scan is best used to view bone injuries, diagnosing lung and chest issues or for detecting cancers. What is an MRI?
This technique is used to identify ligament and tendon injuries, spinal cord injuries, brain tumors, etc. CT scans use radiation in the form of x-rays while MRI uses magnetic fields and radiofrequency pulses to produce detailed pictures of the organs. MRI scans usually provide a far more detailed image of the soft tissues and internal organs such as the brain, skeletal system, reproductive system and other organ systems than that provided by a CT scan.
CT scans re quick and painless, although they do involve an exposure to small amounts of radiation. MRI scans are noisy, require more time and considering the fact that they are done in a small tube-like structure, they can cause some claustrophobia to those prone to it.