Basic Radiology: Foundations and Professional Practice

Without the need for a search for pathology in the human body, there would be no necessity for investigations. Investigations really commence when a doctor or a medical student listens to and asks their patients questions. Thereafter, they examine the patients and determine the appropriate investigations by “external” professionals. Though medical care is a team effort, this author sees investigations as “third party” in the sense that they are outside the immediate relationship between the patient and the physician. These investigations may involve pathologists (and they are various) or medical imaging professionals (there are a myriad of them too). In this book, reference is given to the specialty of radiology and the medical imaging specialists.

Specialized medical imaging techniques have been developed over the years. There is a plethora of them, and more are under development. Specialized medical imaging techniques have added flair to the specialty of radiology, just as it has increased its scope. Not only the possibilities of utility have been increased, but exactitude has also been significantly improved. Gone are the days when “exploratory laparotomy” held sway (especially in developing countries), for pre-operatively, a surgeon had a clear idea of what to encounter in any part of the body. This provides more assurance, a good idea of what type of anesthesia and experience of the anesthetist is required, how long the surgical intervention would last, and essential additional support ab initio. These modalities have come to stay and will only get better. It is important for medical students to have a good idea of them and for every doctor to know their value and for what they should be requested singly, serially, or in combination.

Chapter 3 marks the start of the subsequent chapters that organize medical imaging according to the body’s systems. The author chose to start the book with the respiratory system, structurally focused on the chest and is the part of the body that tends to receive the highest number of requests for the most basic medical imaging modality – radiography. Chest radiographs are still available and valuable globally. Chest X-rays [1] are of greater significance in resource-poor countries; this is because the equipment to perform chest radiography is near ubiquitous in the distribution of these places. 

The axial skeleton is a part of the skeletal system. This component of the human body provides a function that is equivalent to the stem of a tree. Everything tends to revolve around the axial skeleton. It harbors the brain, the spinal cord, and nerve “exits,” just as its rib cage provides accommodation for the heart and lungs. With the combination of flexibility and rigidity, the cartilages and hyoid bone provide stability to the trachea and larynx and avoid the collapse of this “gateway” to the rest of the respiratory system. The bony aspect of the axial skeleton is made up of eighty bones; these bones include the tiny ossicles (malleus, incus, and stapes bilaterally)[1].

A good understanding of the bones, cartilages, and ligaments of the axial skeleton is important for every medical student and practicing doctor. All forms of medical imaging for diagnostic and therapeutic purposes are applicable to the axial skeleton. It deservingly takes Chapter 4 of this book.

To this author, the skeletal system deserves to be discussed in two chapters. It provides a balance in the relative length of the chapters. Appendicular skeleton encompasses the “appendages” of the skeletal system, but they are not appendages in the meaning ascribed to the human appendix. The appendicular skeleton is more or less the “branches” of a tree. Since the stem and roots are important, they cannot fulfill their overall purpose without these branches. The appendicular system receives its empowerment from the axial skeleton and cannot survive without it; the axial skeleton is potent only to a certain level without the appendicular system. This component is described in this chapter. 

Inclusion of the urinary system in this short book on radiology is predicated on the fact that the urinary system helps the human body, according to this author, “to maintain physiological sanity.” So much enters the body through the gastrointestinal system, the skin, and the respiratory system, with the urinary system as the major system responsible for the excretion of metabolic products of food, drugs, and toxic substances. Accumulation of any of these products without a concomitant and expeditious excretion would put the human being at risk of disease (acute or chronic) and premature death.

Due to the complexity of the renal system, there may be congenital abnormalities just as there are many acquired abnormalities – the acquired abnormalities are not necessarily structural ab initio but may start as functional derangements that, over time, cause enough damage to cause structural changes.

 Of the modalities for cardiovascular imaging, the oldest, simplest, and most affordable is chest radiography. One of the challenges with chest radiography is that some practitioners who request this investigation method still believe that they should rely on the specialist to provide them with reports of the images obtained. In developing countries, it is a common experience that the patient needs to return to the hospital or the center where the investigation was conducted and be on the queue to obtain the physical report. Thus, the administrative and logistical efforts become encumbrances that patients and the relatives of the extremely unwell have to bear. When the report on the radiograph, like chest radiograph, indicates “Normal chest findings” the patient either has a sense of relief (as a part of preemployment medical examination) or occasionally feels frustrated (like a patient for whom the physician expected a cardiac basis for their symptoms) as such patients may consider their money wasted for an investigation that was “unnecessary.” Inasmuch as a negative finding gives relief to the physician, it sometimes nudges the physician to request further investigations to find the reason for the illness. Pre-investigation, it is important for a physician to communicate the possible findings with the patient or well client. After the test, when the patient returns for a review, the doctor should ensure that the findings are explained to the patient, particularly the patient who shows interest in knowing as much as possible from the test results. Part of the above scenarios is why this brief Chapter on the cardiovascular system attends to medical imaging and approaches it from an easy-to-understand and easy-to-communicate stance. This way, medical students appreciate the relationship of radiology and clinical care with gross human anatomy, a pre-clinical subject in the medical school.

The gastrointestinal system is an essential system not only for the nutrition of the human body but also for the absorption of medications that are used for the treatment of the numerous ailments that humankind is prone to. The food and drugs mentioned are the ones that are taken by the oral route and not the ones meant for intravenous alimentation or parenteral therapy.

The gastrointestinal system must be robust to carry out these functions mentioned briefly and treated simplistically.

The gastrointestinal system can be investigated by a variety of medical imaging techniques; these depend on the patient's symptoms, duration, findings on physical examination, presence or absence of comorbidity, first episode or recurrence of the symptoms and signs, whether the patient has undergone abdominal surgery (or not) in the past, and other determinants. Therefore, while one patient may require plain radiography, another may need barium meal (depending on the practice area in the world), and yet other patients with presentation referable to the gastrointestinal system may need endoscopy, CT scan, magnetic resonance imaging (MRI), or a combination of these.

For the perpetuation of the human species, the reproductive system is especially important. For couples who choose to procreate, it is a matter of concern if (or when) either of them has health challenges that could make the desire unachievable or stand a low chance of actualization. Without assisted reproduction, both parties must be found fit otherwise, now more available and accessible procedures in many countries are a viable alternative. This chapter does not attend to the theory and practice associated with conception, contraception, multiple pregnancies, antenatal care, normal and abnormal presentations, labor and childbirth, cesarean section and other procedures, or infertility and the disease conditions in the domain of gynecology. The emphasis of this chapter is only on medical imaging pertaining to this essential system. The chapter addresses some of the common investigations in the area of radiology and shows how and why a medical student and practicing physician should be adept at choosing which investigation to request while considering the emotional issues associated with the health condition, the investigation, and the waiting period from carrying out the investigations to obtaining the desired treatment results. 

The purpose of this chapter is to document some of the numerous clinical events that take place in the nervous system. The human nervous system is the most advanced among the members kingdom. It is precisely because of this advancement that has put humankind at the intellectual epitome in the entire universe. While humans are not the biggest or the toughest, they are the most enterprising and the ones who challenge the status quo of the universe.

Unfortunately, the nervous system and its organs are not immune to damage and diseases, and it is imperative for these negative events and disease processes to be identified and stemmed promptly. This chapter deals with the fundamentals of medical imaging which is a great tool in achieving this goal. 

This chapter is occasioned by the need to include a few more conditions to provide this book with further variety of cases, and at the same time maintain the size envisioned for this book.

In this book, various modalities that are used for medical imaging are discussed with examples selected from radiography, ultrasonography, computed tomography scanning, and magnetic resonance imaging.

A part of the body that has been exposed to medical imaging right from the earliest times of radiography is the musculoskeletal system. Incidentally, the axial skeleton and the appendicular skeleton constitute one of the systems of the body that are most commonly exposed to X-rays; this happens in the production of regular plain radiographs and the enhanced forms of radiography, like the use of contrast media and fluoroscopy. X-rays are also used in CT scanning and magnetic resonance imaging.

It is not possible to achieve the desired size of a physically portable and an electronically readily navigable book by including multiple-choice questions on every body system. This goal has limited the contents of this short chapter on MCQs to a small segment of orthopedic surgery. The contents are on the fundamentals only.