Choice of research methods in nephrology

Each of the radiation methods of diagnosis has its strengths and weaknesses. The choice of a method in a specific clinical situation is determined by its diagnostic capabilities (sensitivity, specificity, accuracy), patient safety, cost, accessibility. In this case, the task of the most accurate diagnosis often contradicts the principle of the greatest safety, and methods with a more powerful diagnostic potential (CT, MRI, positron emission tomography) are the most expensive and less affordable.

Ultrasound is different from other methods by combining a wide range of diagnostic capabilities, high safety, relatively low cost and wide availability, so today it forms the basis of radiation diagnosis in nephrology. With this visualization method, as a rule, the examination of the nephrologic patient begins, and in many situations it gives exhaustive information. UZDG significantly expands the possibilities of ultrasound, allowing to detect changes in the vessels of the kidneys, violations of urodynamics and the structure of the parenchyma. Therefore, it is desirable that the ultrasound diagnosis room, where patients with nephrological profile are examined, should be equipped with equipment that allows to carry out ultrasound, and the specialists who work there have appropriate skills.

In complex diagnostic cases the problem consists in a rational combination of diagnostic methods in accordance with their technical capabilities, advantages in different clinical situations, which is impossible without taking into account anamnesis, clinical and laboratory data of the patient.

There are two tactics of radiation diagnostics:

• from simple to complex;
• the shortest way to the fullest possible information.

The first approach consists in the sequential application of several methods of radiation diagnosis, starting with safer and more affordable and ending with the most expensive and high-risk complications. The second approach is to start with the most informative method.

When designing a survey plan, the doctor should be guided by the following principles:

• The diagnostic strength of the method should be adequate to the assigned clinical task;
• to apply more expensive and risk-related complications, research methods should be used only when simpler and safer can not give full information;
• use expensive and risk-associated serious complications methods only when their results can change the treatment and affect the prognosis;
• phased diagnostics: pre-use screening (more accessible and safe methods), and only patients assigned on the basis of their results at risk, carry out refining studies using more expensive and dangerous methods;
• the frequency of repeated studies to assess the dynamics of the pathological process and the effectiveness of treatment should be rationally justified;
• avoid unnecessary duplication of methods close to one another in order to reduce the costs of examination and loading of diagnostic units;
• avoid, whenever possible, a combination of methods, each of which involves the use of a high dose of radiation and / or toxic contrast media.

In accordance with the tactics of application, the methods are divided into two levels. First-level methods are used in the first stage of diagnostic search: the main studies allow to identify the key signs of the underlying disease; additional ones are used in special clinical situations for carrying out advanced differential diagnosis, clarification of concomitant conditions, renal function, etc. The second level of diagnosis is carried out only after the methods of the 1st level, taking into account their results in the case when they make it possible to suspect the disease or when their results seem controversial and questionable. Second-level studies include methods that are associated with an increased risk of complications or are the most expensive, available only in large diagnostic centers.

[1], [2], [3], [4], [5], [6], [7], [8], [9]