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A clinical observation of focal accumulation of ⁹⁹(m)Tc-pyrophosphate in aortic aneurysm, simulating skeletal pathology of the lumbar vertebra in planar scintigraphy mode, is presented. Additional single-photon emission computed tomography combined with computed tomography-something view allowed to confirm that the radiotracer uptake focus was localized in the distal part of the aneurysm, in the zone of lumen subocclusion by a calcified thrombus. It is suggested that the local tracer accumulation is not only due to calcification but also due to inflammatory, a factor that plays a role in the genesis of aortic aneurysm.

Objective: to specify frequency, patterns and diagnostic significance of extraosseous soft tissue findings in 99mTc-pyrophosphate skeletal scintigraphy., Material and Methods: Results of skeletal scintigraphy from 1060 patients (447 men, 613 women) were analyzed. Scanning in "whole body" mode started in 3-4 hours after 740 MBq of radiotracer activity intravenous administration, and performed in anterior and posterior projections in continuous table motion mode at rate of 6-8 cm per minute. Single photon emission computed tomography/computed tomography (SPECT/CT) was additionally performed when necessary., Results: Extraosseous scintigraphic findings were discovered in 161 (15.2%) patients, they can be divided into three categories: nephrourological (7.7%), soft tissue (5.4%) and artifacts (2.1%). First category included anatomical and functional changes in the urinary system (kidney location anomalies and nonobstructive uropathies). SPECT/CT was performed to differentiate calycostasis in the projection of the upper group of calyces and focal changes of the ribs. Soft tissue extrarenal findings included diffuse or focal RP hyperfixation within breasts (29 patients), thyroid glands (15), myocardium (5), scrotum (4) and abdominal cavity (4). Symmetrical increased RP accumulation in breast or thyroid lobes was accepted as normal. Pathologic soft tissue findings in 11 patients were verified by history or instrumental data: breast cancer (2), testicular cancer (1), nodular goiter (2), uterine fibroids (2), primary cancer with liver metastases (1), association of "hot kidney" phenomenon with chemotherapy (2), and "superscan" phenomenon with myelofibrosis (1). Causes of radiotracer artifacts in the liver and spleen (14) were of radiopharmaceutical factors, in axillary lymph node (7)--partially infiltrative radiopharmaceuticals administration, in the colon (1)--previous myocardial perfusion scintigraphy., Conclusion: Analysis and interpretation of abnormal extraosseous findings in skeletal scintigraphy is an essential component of additional diagnostic information, that can influence subsequent diagnostic and therapeutic tactics.

Based on the analysis of the data available in the literature and own clinical observations, the authors consider the diagnostic value of the little known scintigraphic phantom kidney phenomenon, a vascular pool that is detected at the angiographic stage of 99mTc-DTPA dynamic renal scintigraphy and that mimics a removed or absent kidney. The paper describes two cases of the phantom kidney. In one case, the phantom kidney detected on the side of nephrectomy manifested a kidney cancer recurrence in the bed of the removed organ; in the other, the kidney-like vascular pool in the patient with left-sided pelvic dystopic kidney was due to the recording of the intestinal vasculature at the site of the expected kidney location. Adherence to a number of methodical conditions for conducting a study, as well as combined single-photon emission computed tomography/computed tomography examination will be able to avoid interpretation errors and to ensure an adequate further diagnostic algorithm.