[Comparison of the effectiveness of various methods for determining the level of metanephrines in the diagnosis of pheochromocytomas]

BACKGROUND

Pheochromocytoma (PHEO) is a tumor from the chromaffin tissue of the adrenal medulla, capable of hyperproduction of catecholamines. The increased production of hormones by the tumor leads to catecholamine crises, which have a pathological effect on all organs and systems. In the primary diagnosis of pheochromocytomas, it is important to determine the level of the metabolite of catecholamines - metanephrines. Currently, in clinical practice, various methods are used to determine the level of this metabolite: in blood plasma or in urine, total or only free form, fractionated analysis or unfractionated.

AIM

Comparison of the effectiveness of various methods for determining the level of metanephrines for the diagnosis of pheochromocytomas.

MATERIALS AND METHODS

A retrospective single-center cohort study was conducted on a sample of patients who were initially operated on for adrenal neoplasm at the Pirogov St. Petersburg State University High Medical Technology Clinic from November 2007 to December 2022 and who passed analysis to determine the level of blood or urine metanephrins before surgical treatment. The results of tests for metanephrine and tumor size were evaluated.

RESULTS

1088 patients with adrenal neoplasms who underwent surgical treatment were examined, of which 348 had histologically confirmed the presence of pheochromocytoma. Four types of metanephrine assays were compared: free fractionated plasma metanephrines (232 patients), unfractionated daily urine metanephrines (431 patients), fractionated total daily urine metanephrines (427 patients) and fractionated free daily urine metanephrines (178 patients). The greatest sensitivity was demonstrated by the analysis of free fractionated plasma methanephrines (95.4%). Unlike others, the sensitivity of this analysis did not decrease in the group of patients with small pheochromocytomas (3 cm or less). The greatest specificity was demonstrated by the analysis of unfractionated metanephrines in daily urine (97.8%), with the lowest sensitivity among all tests (67.6%). The study of fractionated total daily urine metanephrins showed good results of sensitivity and specificity, only slightly inferior to the best indicators, and the analysis of free daily urine metanephrins demonstrated unexpectedly low efficiency. There is a positive correlation between the level of metanephrine in the blood and the size of the tumor.

CONCLUSION

Based on the data obtained, the preferred assays for the primary diagnosis of pheochromocytoma can be considered the determination of fractionated free plasma metanephrines and fractionated total daily urine metanephrines, which is consistent with relevant clinical recommendations. It was found that the size of the tumor correlates with the severity of an increase in the level of metanephrins determined by any of the described methods.

[Diagnostic value of ct in examination of patients with adrenal cancer]

BACKGROUND

In most cases adrenal tumours are detected by accident while performing medical imaging tests for other diseases. These findings are treated as adrenal incidentaloma. Prevalence of incidentalomas detected on CT scans is up to 4%. According to different authors, 4-12% of all adrenal tumours are adrenocortical carcinomas. As for today, the most significant medical imaging technique is CT scan with bolus IV injection of contrast agent and assessment of tumour's density. The analysis of the results of CT imaging in 67 patients with ACC was carried out according to a single protocol. The main signs characteristic of this disease are described. It is very important to evaluate typical signs of ACC on CT scans for risk assessment of ACC before surgical treatment. If malignant tumour is suspected during preoperative examination, it is extremely important to choose the right surgical treatment strategy.

AIM

To evaluate the significance of CT as the main method of preoperative diagnosis in patients with malignant tumors of the adrenal cortex. Studying CT semiotics of adrenocortical cancer in a large group of patients using a single standard imaging protocol. Find the main radiological symptoms characteristic of adrenocortical cancerMATERIALS AND METHODS: Here are the results of retrospective study of CT scans performed on 67 patients with adrenocortical carcinoma who received treatment in the Department of Endocrine Surgery of Saint-Petersburg State University N.I. Pirogov Clinic of High Medical Technologies during 2012-2020. The diagnostic significance of CT in patients with ACC was assessed.

RESULTS

The most common features of ACC: tumour heterogeneity (84.3%), tumour's size 3-9 cm (75%), signs of invasion into surrounding structures (10%), pre-contrast density above +30 HU (75%), absolute contrast washout less than 60% (68.8%), relative contrast washout less than 40% (64.6%)CONCLUSION: CT scan with IV contrast was not able to show any definitive pathognomonic signs of ACC. Nevertheless, CT scan should be performed in all patients with suspected (or confirmed using other medical imaging technique) adrenal tumour according to standard protocol. Bolus injection of contrast agent should be performed in all patients with tumour's pre-contrast density above +5 HU.

Draft of the clinical practice guidelines “Adrenal incidentaloma”

The wider application and technical improvement of abdominal imaging procedures in recent years has led to an increasingly frequent detection of adrenal gland masses — adrenal incidentaloma, which have become a common clinical problem and need to be investigated for evidence of hormonal hypersecretion and/or malignancy. Clinical guidelines are the main working tool of a practicing physician. Laconic, structured information about a specific nosology, methods of its diagnosis and treatment, based on the principles of evidence-based medicine, make it possible to give answers to questions in a short time, to achieve maximum efficiency and personalization of treatment. These clinical guidelines include data on the prevalence, etiology, radiological features and assessment of hormonal status of adrenal incidentalomas. In addition, this clinical practice guideline provides information on indications for surgery, postoperative rehabilitation and follow-up.

[The future of computer-aided diagnostics in chest computed tomography]

Recently, more and more attention has been paid to the utility of artificial intelligence in medicine. Radiology differs from other medical specialties with its high digitalization, so most software developers operationalize this area of medicine. The primary condition for machine learning is met because medical diagnostic images have high reproducibility. Today, the most common anatomic area for computed tomography is the thorax, particularly with the widespread lung cancer screening programs using low-dose computed tomography. In this regard, the amount of information that needs to be processed by a radiologist is snowballing. Thus, automatic image analysis will allow more studies to be interpreted. This review is aimed at highlighting the possibilities of machine learning in the chest computed tomography.