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Lung perfusion scan shows significantly reduced tracer distribution in bilateral bronchopulmonary segments. Quantification of segmental perfusion is given in image
Source publication
Tc-99m macro aggregated albumin (MAA) is synonymous for lung perfusion scintigraphy and is part of the study in the evaluation of pulmonary thromboembolism. We wanted to highlight the utilities of Tc-99m MAA other than pulmonary embolism as a pictorial assay.
Patients referred for Tc-99m MAA scintigraphy under various indications were included in t...
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Purpose
While computed tomography pulmonary angiography plays an effective role in the diagnosis and prognosis of pulmonary embolism (PE), there are not enough studies regarding ventilation/perfusion (V/Q) scintigraphy. We aimed to evaluate the clinical outcomes of PE patients whose V/Q scintigraphy was reported as high probability for PE.
Method...
Objective:
To highlight the importance of the lung ventilation scintigraphy (LVS) to study the regional distribution of lung ventilation and to describe most frequent abnormal patterns of lung ventilation distribution obtained by this technique in COPD and to compare the information obtained by LVS with the that obtained by traditional lung functio...
Background and aims
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Lung scintigraphy remains an option for the evaluation of pulmonary embolism. Beware the use of a normal Chest Radiograph (CXR) as a surrogate for normal ventilation if perfusion scans are performed without ventilation studies and have a low threshold for contemporaneous CT imaging, particularly in the context of the current COVID-19 pandemic.
Deep vein thrombosis (DVT) is an important life threatening condition that is difficult to diagnose, particularly in the early stages. Looking for DVT in lower limb can be considered ancillary in suspected cases of pulmonary embolism (PE) indirectly highlighting a cause and effect relationship of a single disease (i.e cause being DVT and effect is...
Citations
... Tc-99m MAA scans carry a less than 1 in 10,000 risk of serious allergic reaction [17], have an associated radiation dose and a theoretical risk of cerebral and other visceral microemboli [1]. Costs of a Tc-99m MAA scan are likely to be similar to a ventilation perfusion scan for pulmonary embolus, which in the United States of America is $683 [18], as the Tc-99m MAA scan used to quantify the right to left shunt is the same as the perfusion portion of a ventilation perfusion scan for pulmonary embolus, just that whole body images are taken instead of just the lungs [19]. Saline microbubble contrast echocardiograms do not have radiation associated risks and are not invasive as they are generally performed as transthoracic scans. ...
... Enlarged right atrium and right ventricle [42] Extrapulmonary tracer uptake [19] Hereditary haemorrhagic telangiectasia/ Osler-Weber-Rendu Syndrome (with pulmonary arteriovenous malformations) ...
A 60-year-old lady with alcoholic liver disease developed central cyanosis and orthodeoxia. A technetium-99m macro-aggregated albumin lung perfusion scan and contrast echocardiogram were performed. A 13% right to left shunt was calculated from the macro-aggregated albumin scan. There were more bubbles in the left heart than the right at the end of the contrast echocardiogram. Hepatopulmonary syndrome was therefore diagnosed. The patient had a liver transplant five days after these investigations. Further discussion about hepatopulmonary syndrome will be provided. Normally, macro-aggregated albumin scans are performed in few centers, however as this was at the height of the coronavirus pandemic, the scan needed to be performed locally to reduce the chance of the patient getting coronavirus. Local radiographers were remotely instructed on conducting the macro-aggregated albumin scan by a larger center to provide a timely and important investigation in a logistically difficult scenario.
... Not all hospitals will have the relevant equipment and facilities to perform Tc99m-MAA scans. Tc-99m MAA scans carry a less than 1 in 10,000 risk of serious allergic reaction [17], have an associated radiation dose and a theoretical risk of cerebral and other visceral microemboli [1] Costs of a Tc-99m MAA scan are likely to be similar to a ventilation perfusion scan for pulmonary embolus, which in the United States of America is $683 [18], as the Tc-99m MAA scan used to quantify the right to left shunt is the same as the perfusion portion of a ventilation perfusion scan for pulmonary embolus, just that whole body images are taken instead of just the lungs [19]. Saline microbubble contrast echocardiograms do not have radiation associated risks and are not invasive as they are generally performed as transthoracic scans. ...
... Enlarged right atrium and right ventricle [42] Extrapulmonary tracer uptake [19] Hereditary haemorrhagic telangiectasia/ Osler-Weber-Rendu Syndrome (with pulmonary arteriovenous malformations) ...
A 60-year-old lady with alcoholic liver disease developed central cyanosis and orthodeoxia. A technetium-99m macro-aggregated albumin lung perfusion scan and contrast echocardiogram were performed. A 13% right to left shunt was calculated from the macro-aggregated albumin scan. There were more bubbles in the left heart than the right at the end of the contrast echocardiogram. Hepatopulmonary syndrome was therefore diagnosed. The patient had a liver transplant five days after these investigations. Further discussion about hepatopulmonary syndrome will be provided. Normally, macro-aggregated albumin scans are performed in few centers, however as this was at the height of the coronavirus pandemic, the scan needed to be performed locally to reduce the chance of the patient getting coronavirus. Local radiographers were remotely instructed on conducting the macro-aggregated albumin scan by a larger center to provide a timely and important investigation in a logistically difficult scenario. 2023 Aug; 17(8):65-77 ::
... The scintigraphy images supported the biodistribution data in every detail. 99m Tc labeled macro-aggregated albumin (Tc-99 m -MAA) is an essential diagnostic technique in assessing pulmonary regional perfusion [59]. The time-dependent uptake study of Tc-99 m -MAA is an extremely effective non-invasive process for monitoring drug/formulation therapeutic efficacy [60]. ...
Lung cancer remains the leading cause of cancer death, with an estimated 1.8 million deaths. Triticum-lectin protein, or Triticum-agglutinin (TA), can precisely identify and couple with lectin receptors, glucose transporters, and N-acetyl glucosamine residues overexpressed on lung cancer cells, facilitating receptor-mediated drug targeting. We have developed a site-specific TA-coupled nanoparticle (NPs) of luteolin (TA-conjugated LUT-NPs) to combat benzo(a)pyrene-induced lung carcinogenesis in rats. LUT-NPs and TA-conjugated LUT-NPs were formulated and evaluated for their size, surface morphology, drug loading, entrapment efficiency, stability, in-vivo toxicity, scintigraphic imaging of lungs in rats by 99mTc macro-aggregated albumin lung perfusion, and biodistribution. The formulations were stable and non-toxic. The studies on lung cancer cells showed predominant cellular internalization, cancer cell-specific cytotoxic potential, and apoptotic potential of TA-conjugated LUT-NPs. TA-conjugated LUT-NPs had a superior therapeutic outcome as evidenced by improved histology and lung ultrastructure evaluated by scanning electron microscopy. The study has indicated the excellent potential of TA-conjugated LUT-NPs for site-specific drug delivery in lung carcinogenesis.
Graphical Abstract
Triticum-agglutinin surface-modified luteolin-loaded biodegradable nanoparticles in rat pulmonary carcinogenesis
... The specificity and efficacy of the tracer agent can be quantified by the intensification of radiopharmaceuticals in afflicted cells. Along with the aforementioned pathways, some others are also in operation, including phagocytosis [118], ion exchange [119], filtration [120], cellular migration [121], and facilitated diffusion [122]. The success of radiopharmaceuticals depends on their accumulation in specific target cells, expressed as a percentage of the amount that was injected into the organ or tissue. ...
Radiopharmaceutical therapy, which can detect and treat tumours simultaneously, was introduced more than 80 years ago, and it has changed medical strategies with respect to cancer. Many radioactive radionuclides have been developed, and functional, molecularly modified radiolabelled peptides have been used to produce biomolecules and therapeutics that are vastly utilised in the field of radio medicine. Since the 1990s, they have smoothly transitioned into clinical application, and as of today, a wide variety of radiolabelled radionuclide derivatives have been examined and evaluated in various studies. Advanced technologies, such as conjugation of functional peptides or incorporation of radionuclides into chelating ligands, have been developed for advanced radiopharmaceutical cancer therapy. New radiolabelled conjugates for targeted radiotherapy have been designed to deliver radiation directly to cancer cells with improved specificity and minimal damage to the surrounding normal tissue. The development of new theragnostic radionuclides, which can be used for both imaging and therapy purposes, allows for more precise targeting and monitoring of the treatment response. The increased use of peptide receptor radionuclide therapy (PRRT) is also important in the targeting of specific receptors which are overexpressed in cancer cells. In this review, we provide insights into the development of radionuclides and functional radiolabelled peptides, give a brief background, and describe their transition into clinical application.
... The question remains of what embolic effect may be caused by the presence of these remaining 99m Tc MAA microparticles by the time of treatment with up to 44 million Y-90 resin microspheres. Although there is no clinical data confirming the time for complete absorption or elimination of 99m Tc MAA in the liver, the pharmacokinetics of MAA in the lungs from perfusion studies show that elimination depends on the size of MAA [13]. Considering a variable size between 5 to 140 microns, the time for complete absorption in the lung varies from two to eight hours. ...
Historically, selective internal radiation therapy (SIRT) with yttrium-90 (Y-90) requires a two-week interval between workup and treatment (map and treat). The intervening gap between workup and treatment is used to plan for the dose required and obtain delivery of the radioactive Y-90. During the coronavirus disease 2019 pandemic, the delivery of a robust SIRT service was challenging due to unprecedented demands on all hospital services. Emergent practice changes were required to ensure this service could still be delivered to patients while retaining sufficient inpatient hospital beds and services for acutely unwell patients.
In response to this, the interventional radiology team proposed the retention of a full SIRT service by removing the historical two-week interval between map and treat, delivering both components of the SIRT procedure on the same day. A traditional approach using femoral access would require a prolonged period of immobility and potentially an overnight stay. By adopting a transradial approach without sedo-analgesia, an ambulatory day-case map and treat SIRT with no post-procedure immobilisation was performed.
This case report demonstrates the technical feasibility of same-day ‘map-and-treat’ SIRT, highlighting a paradigm shift from the conventional femoral access method and immobilisation to an ‘ambulatory’ approach with immediate mobilisation post-procedure.
... This exciting approach aims to develop multimodal theragnostic systems that use coencapsulation of multiple diagnostic modalities and therapeutics in targeting nanomedicines platforms (Patra et al., 2018). An and Zhang (2017), Gandhi et al. (2013), Lee and Group (2019), Raval et al. (2021), Tambe et al. (2021g), Gadekar et al. (2021) ...
Bionanotechnology (BNT) is a vital tool of translational research. Nano-biointerface has created nanomaterials, which are similar to endogenous biomolecules. It is widely explored as therapeutics and diagnostics and showed great potential in theranostic applications. Moreover, it is a rescue tool for the environment against global deterioration and disturbed ecosystems. The physical and chemical properties of nanoparticles (NPs) affect various aspects of life on the earth. Therefore nanopollution and nanotoxicity caused by these engineered NPs have greatly influenced the environment and resulted in a risk on the ecological and environmental balance. The chapter gives a detailed overview of nanopollution and its hazardous effect on air quality, land, and aquatic toxicity.
Furthermore, it also discusses the effect of nanopollution on each organ of the human body. The majorly overlooked aspect of nanopollution and ecotoxicity is the core of this chapter; however, it also explains the savior aspects of BNT. Health hazards of specific BNT tools such as magnetic NPs, surface plasmon resonance, quantum dots, carbon nanotubes, biophotonic devices, gold NPs, graphene, and dendrimer are also discussed in detail. Finally, we can conclude that risk assessment, regulatory aspects, and ethical challenges need extra attention.
... We proceed with SPECT/CT with Technetium-99 m (Tc-99 m) macro aggregated albumin (MAA) and Sestamibi scan. Previous studies have described Tc-99 m MAA's role in detecting RA thrombus and pulmonary embolism [25,26]. Sestamibi is an established radiopharmaceutical for myocardial perfusion and malignancy evaluation, but its role in evaluating pericardial mass has 21:85 never been described [27][28][29][30]. ...
Background
Pericardial hematoma is blood accumulation in the pericardial space. Although rare, it could arise in various conditions, such as after cardiac surgery. Clinical diagnosis of pericardial hematoma is implausible; thus, cardiac imaging plays a pivotal role in identifying this condition. We presented a case of multiple pericardial hematomas, which was found as an incidental finding in post-cardiac surgery evaluation. We highlighted the diagnostic challenge and the key features of multi-modality cardiac imaging in pericardial hematoma evaluation.
Case presentation
An asymptomatic, 35-years old male, who underwent surgical closure of secundum atrial septal defect (ASD) one month ago, came for routine transthoracic echocardiography evaluation. An intrapericardiac hematoma was visualized at the right ventricle (RV) 's free wall side. Another mass with an indistinct border was visualized near the right atrium (RA). This mass was suspected as pericardial hematoma differential diagnosed with intracardiac thrombus. Cardiac computed tomography (CT) scan showed both masses have an attenuation of 30–40 HU; however, the mass's border at the RA side was still not clearly delineated. Mild superior vena cava (SVC) compression and multiple mediastinal lymphadenopathies were also detected. These findings are not typical for pericardial hematomas nor intracardiac thrombus; hence another additional differential diagnosis of pericardial neoplasm was considered. We pursued further cardiac imaging modalities because the patient refused to undergo an open biopsy. Single-photon emission computer tomography (SPECT)/CT with Technetium-99 m (Tc-99 m) macro-aggregated albumin (MAA) and Sestamibi showed filling defect without increased radioactivity, thus exclude the intracardiac thrombus. Cardiac magnetic resonance imaging (MRI) reveals intrapericardial masses with low intensity of T1 signal and heterogeneously high intensity on T2 signal weighted imaged and no evidence of gadolinium enhancement, which concluded the diagnosis as subacute pericardial hematomas. During follow-up, the patient remains asymptomatic, and after six months, the pericardial hematomas were resolved.
Conclusion
Pericardial hematoma should be considered as a cause of pericardial masses after cardiac surgery. When imaging findings are atypical, further multi-modality cardiac imaging must be pursued to establish the diagnosis. Careful and meticulous follow-up should be considered for an asymptomatic patient with stable hemodynamic.
... Therefore, this perfusion lung scan with Tc-99 m MAA aggregates also used to assess blood flow in pulmonary arteries. A similar procedure in which Tc-99 m MAA is injected in hepatic artery through a catheter, it is delivered via hepatic blood flow to the capillaries in the liver [19,28]. ...
... Naturally, existing somatostatin (SST) complexes of peptide formation are of two types. One with 14 amino acids (SST 14 ) and other with 28 amino parts and designated as SST 28 . In human beings, SST receptors have been recognized on cell surface of neuroendocrine region and on lymphocytes. ...
Scintigraphic techniques have opened a new era of developments in the localization of infectious and cancerous foci. Diseases area targeting mechanisms of radiopharmaceuticals encompasses visualization, characterization, and measurement of physiological and biological functioning at targeted sites in addition to measure the area and density of the disease. The accumulation of a radiopharmaceutical at specific organ is based upon numerous processes such as enzymatic interactions, receptor binding site, transport of chemical species and elimination of damaged cells from circulation by a normal metabolic process. PET and SPECT are developing scanning techniques that provides effective diagnostic tool to identify pathophysiology of diseased cells. In this chapter, we are exploring and explaining different mechanisms of radiopharmaceutical localization for imaging and therapeutic processes. The knowledge of these mechanisms will help to develop target based new radiopharmaceuticals using variety of medically used radioisotopes either for imaging or therapy of diseased cells.
... The injection of platelets is concerning, particularly, if the platelets become stimulated by the labeling procedure and can exacerbate thrombosis upon delivery; control studies should be conducted before proceeding to the clinical phase to assure the safety of the scan. There are many approaches for detection of the thrombosis including Doppler ultrasonography, CT angiography, MR angiography, perfusion imaging with MAA, and clot detection with specific anti-platelet antigen antibodies (9,(33)(34)(35)(36). Although angiography and venography via catheterization are the standard methods in many conditions, they are invasive and less clinically indicated. ...
99mTc-HMPAO labeled platelet (LP) imaging may integrate thrombosis imaging into routine clinical procedures. In the current study, we assessed the feasibility of the use of 99mTc-HMPAO LP for imaging of small clots in an animal model. Thrombosis was induced by application of FeCl3 solution in the distal part of the inferior vena cava (IVC) of a 6100 g anesthetized rabbit and in a male Wistar rat weighing 420 g. Twenty minutes later, 178 MBq 99mTc-HMPAO LP was injected. 99mTc-HMPAO LP preparation was done as defined and standardized in a previous report. Whole body and SPECT imaging were done 60, 90, and 120 min after tracer injection. Then, the clotted part of the vein was extracted and then its activity and pathologic evaluations were compared with the proximal part of the IVC at a similar volume. A 17 × 6 mm clot was clearly detected with both planar and SPECT imaging. The count to pixel ratio (CPR) of the clotted part of the vein was 35, 40, and 40 compared to the non-clotted vein (i.e. 19, 18, and 21) at 60, 90, and 120 min, respectively. After clot extraction, the CPR decreased to 14. The clot activity was 0.44 MBq compared to 0.01 MBq of the normal control vein. Also, clot induction was pathologically proven. 99mTc-HMPAO LP preparation is logistically possible in clinical nuclear medicine and the ability of imaging small size clots encourages future trials for real clinical thrombotic scenarios.
... Thus, the fraction of Tc-99-MAA leaking into lungs is typically estimated by drawing a region of interest over the lungs and liver on the planar images as shown in the following function: [12] For a patient to be accepted ideal and appropriate to undergo Y-90 radioembolization, the lung shunting fraction (SF) must not exceed 20%. [15] To assess tumor to liver uptake ratio plays a major role in accomplishing Y-90 MPA, in which the borders of tumor and normal liver are pointed out optically and tumor/liver ratio (TLR) is determined as: [17] SF= Countslungs Eq.4 Countslungs+Countsliver ...
