99mTc-red blood cells SPECT and planar scintigraphy in the diagnosis of hepatic hemangiomas

Abstract

The aim of the study is the assessment of the value of SPECT (single photon emission computerized tomography) using 99mTc-labeled red blood cells in the detection of liver hemangioma, in comparison to planar imaging. With planar red blood cell scintigraphy, sensitivity of the method was 76%, specificity 98%, positive predictive value 98% and negative predictive value 79%. With SPECT, sensitivity of the method was 95%, specificity 98%, positive predictive value 98% and negative predictive value 94%. The smallest lesion detected by planar red blood cell scintigraphy was 1.2 cm, and with SPECT red blood cell scintigraphy 0.8 cm. The use of 99mTc-labeled red blood cells SPECT improved the sensitivity much more in smaller lesions (0.8 to 2 cm), than in bigger ones (2-5 cm). SPECT with radiolabeled red blood cells significantlyy improves the results of scintigraphic findings, especially in the small lesions.

To what extent can diverse types of liver lesions mimic hemangiomas? A retrospective quantitative analysis of masses found to be positive in SPECT/CT with labeled blood cells – a preliminary report

“…It must be emphasized, however, that no quantitative analysis was performed in any of these cases. Positive predictive value of the examination for hemangioma is accepted to be above 90%, reaching 98% in some studies [3]. It means that as much as a few percent of RBC-positive foci can be wrongly interpreted as hemangiomas, although they might require an urgent therapy.…”

“…Contrary to radiological techniques, scintigraphy with technetium-99m-labeled patient’s own red blood cells (Tc-99m-RBC), especially SPECT and SPECT/CT (single photon emission computed tomography/computed tomography), seems to possess very high sensitivity and specificity [1–3,6]. Typical findings include lack of perfusion (early phase, scintigraphically evaluable only in some lesions) and markedly enhanced RBC accumulation in delayed phase (phenomenon referred to as “perfusion/blood-pool mismatch”).…”

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“…Before the usage of SPECT technique, <3 cm lesions couldn't be detected scintigraphically [15]. Lesions that have >1.5 cm in size can be identified clearly with SPECT imaging [16]. The smallest lesion size that could be seen was 0.9 cm in a recent literature [1].…”

Compartmentalized agents: A powerful strategy for enhancing the detection sensitivity of chemical exchange saturation transfer contrast

“…Several internalization routes for entrapping exogenous molecules inside RBCs have been investigated over the last 2 decades, with the aim of (i) loading drugs to generate long-circulating drug-delivery systems 59 ; and (ii) loading labeling agents to make RBCs detectable by imaging techniques (e.g., MRI, OI, and SPECT). 60,61 Of the different routes that are normally available for the loading of small molecules inside cells (micropinocytosis, electroporation, hypotonic swelling, endocytosis, sonoporation, etc. ), hypotonic swelling has been shown to be one of the most efficient and safest because it does not affect the functionality of RBCs, which retain their hematological properties (i.e., MHC, MCHC, MCV, and RDW), mechanical properties (response to osmotic stress, deformability), and the capability to carry oxygen.…”

“…RBCs are suitable for loading with small hydrophilic metal complexes, with Ln‐HPDO3A complexes (Ln = Eu, Gd, Dy, Tm, and Yb) being preliminary tested. Several internalization routes for entrapping exogenous molecules inside RBCs have been investigated over the last 2 decades, with the aim of (i) loading drugs to generate long‐circulating drug‐delivery systems 59 ; and (ii) loading labeling agents to make RBCs detectable by imaging techniques (e.g., MRI, OI, and SPECT) 60,61 …”