A deep learning anthropomorphic model observer for a detection task in PET.

BACKGROUND: Lesion detection is one of the most important clinical tasks in positron emission tomography (PET) for oncology. An anthropomorphic model observer (MO) designed to replicate human observers (HOs) in a detection task is an important tool for assessing task-based image quality. The channelized Hotelling observer (CHO) has been the most popular anthropomorphic MO. Recently, deep learning MOs (DLMOs), mostly based on convolutional neural networks (CNNs), have been investigated for various imaging modalities. However, there have been few studies on DLMOs for PET. PURPOSE: The goal of the study is to investigate whether DLMOs can predict HOs better than conventional MOs such as CHO in a two-alternative forced-choice (2AFC) detection task using PET images with real anatomical variability. METHODS: Two types of DLMOs were implemented: (1) CNN DLMO, and (2) CNN-SwinT DLMO that combines CNN and Swin Transformer (SwinT) encoders. Lesion-absent PET images were reconstructed from clinical data, and lesion-present images were reconstructed with adding simulated lesion sinogram data. Lesion-present and lesion-absent PET image pairs were labeled by eight HOs consisting of four radiologists and four image scientists in a 2AFC detection task. In total, 2268 pairs of lesion-present and lesion-absent images were used for training, 324 pairs for validation, and 324 pairs for test. CNN DLMO, CNN-SwinT DLMO, CHO with internal noise, and non-prewhitening matched filter (NPWMF) were compared in the same train-test paradigm. For comparison, six quantitative metrics including prediction accuracy, mean squared errors (MSEs) and correlation coefficients, which measure how well a MO predicts HOs, were calculated in a 9-fold cross-validation experiment. RESULTS: In terms of the accuracy and MSE metrics, CNN DLMO and CNN-SwinT DLMO showed better performance than CHO and NPWMF, and CNN-SwinT DLMO showed the best performance among the MOs evaluated. CONCLUSIONS: DLMO can predict HOs more accurately than conventional MOs such as CHO in PET lesion detection. Combining SwinT and CNN encoders can improve the DLMO prediction performance compared to using CNN only.

A Rare Case of Abnormal Diffuse Brain Uptake on an 123I MIBG Scan in a Patient With High-Risk Neuroblastoma.

ABSTRACT: 123I-meta-iodobenzylguanidine (123I-MIBG) is extensively used for initial staging and response evaluation in children with neuroblastoma. Physiological uptake of 123I-MIBG occurs in the salivary glands, liver, adrenal gland, myocardium, bowel, and thyroid gland. 123I-MIBG cannot cross an intact blood-brain barrier. We present the rare case of a 3-year-old boy with neuroblastoma and meningeal metastases who underwent an 123I-MIBG scan for disease restaging that showed abnormal brain uptake. Abnormal MIBG uptake in the brain can occur if there is disruption of the blood-brain barrier either secondary to metastases or after damage to blood-brain barrier.

The scintigraphic, biodistribution and histopathological evaluation of the effect of experimental 131I administration on the gastrointestinal system and the demonstration of the Na+/I- symporter by immunohistochemistry in rats.

OBJECTIVE: The aim of this study was to investigate histopathological changes and biodistribution of iodine-131 (I) in the gastrointestinal system (GIS) and also Na/I Symporter (NIS) presence by immunohistochemically in the experimental treatment of rats with radioactive iodine (RAI). MATERIALS AND METHODS: Rats were divided into experimental and control groups as random early group 2 (24 h), intermediate group 3 (3 weeks), and late period group 4 (3 months). Experimental groups were administered 100 MBq (∼3 mCi, 12 mCi/kg) by orogastric route with orogastric tube. Scintigraphic iodine screening images were obtained 24 h, 3 weeks, and 3 months after RAI, and GIS tissues were removed, and immunohistochemical methods were used to demonstrate NIS with RAI biodistribution and histopathology. RESULTS: According to the results of scintigraphy, the most prominent activity involvement was observed in the thyroid gland at group 2, and significant activity was observed in the stomach. In the group 3 and group 4 images, owing to the physiological and biological half-life of the iodine and low resolution of the gamma camera, no secondary focal activation was observed. The highest RAI biodistribution value in all groups was in the stomach, ileum and oesophagus. In the immunohistochemical examination of NIS, the highest staining sequence was observed in all groups respectively in the stomach, oesophagus, tongue, colon, saliva, duodenum, rectum, ileum and jejunum. The increase of NIS immunohistochemically stained more intensely was observed in the RAI-administered groups. CONCLUSION: The amount of NIS is important for the absorption of RAI after administration.

Apoptosis and cell proliferation in short-term and long-term effects of radioiodine-131-induced kidney damage: an experimental and immunohistochemical study.

OBJECTIVE: Radioiodine-131 is a radionuclide that is used for therapeutic purposes in hyperthyroidism and thyroid cancer. The aim of this study was to evaluate apoptotosis and proliferative changes in radioiodine-related kidney damage. MATERIALS AND METHODS: Three groups (n=10/group) of rats were used as follows: the rats were in group 1 untreated, and the rats in groups 2 and 3 were treated once with oral radioiodine (111 MBq). The animals in group 2 were killed at the end of the seventh day and the rats in group 3 were killed at the end of the 10th week. The kidneys were removed and evaluated immunohistochemically. The presence of radioiodine in the kidneys was shown by the Na+/I-symporter antibody and proliferating cell nuclear antigen, Ki-67, caspase-3, caspase-8, caspase-9, and terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling assay were used to detect cell proliferation and apoptosis. RESULTS: Na+/I-symporter protein accumulation in the kidneys was observed to be significantly greater in group 2 than in group 3 (P<0.05). All the immunohistochemical analyses showed that cell proliferation and apoptosis began on the seventh day and peaked in the 10th week. The proliferating cell nuclear antigen, Ki-67, and caspase expressions and terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling values were all found to be statistically significantly increased in group 3 compared with the other groups (P<0.05). CONCLUSION: Radioiodine caused cell proliferation and apoptosis as shown by immunohistochemistry.

Expression of ADAMTS2 and ADAMTS5 in the salivary gland of rats after radioiodine therapy.

OBJECTIVE: The aim of this study was to investigate the presence of ADAMTS2 and ADAMTS5 in the salivary gland (SG) of rats after high-dose radioiodine therapy. METHODS: A total of 36 male Wistar albino rats were used for this study. Thirty-six male rats were divided randomly into six groups: control and five radioactive iodine (RAI) treatment groups of six rats each. All animals were killed. The evaluation of biodistribution and histopathological studies were carried out on the SGs removed. Real-time PCR and immunohistochemical analysis were carried out to determine mRNA and protein expression levels of ADAMTS genes. Differences between the groups were evaluated statistically. RESULTS: In RAI-treated groups, ADAMTS2 and ADAMTS5 gene expression was observed to increase, whereas there was no mRNA or protein expression in the control group. There were statistically significant increases in the mRNA expression of ADAMTS2 (all RAI-administered groups in parathyroid gland and at 4, 24, and 48 h in submandibular gland) and ADAMTS5 (all RAI-administered groups, except on the 30th day in the parathyroid gland and all RAI groups in submandibular gland). Through immunohistochemical analysis, the staining pattern in the extracellular source was also observed in the overexpressed ADAMTS2 and ADAMTS5 groups. Nuclear coarsening and partial focal subnuclei vacuolization were determined in all RAI-administered groups with histopathological examinations. CONCLUSION: An increase in the mRNA expression levels of ADAMTS2 and ADAMTS5 genes was detected in the RAI-administered groups. These results suggested that ADAMTS2 and ADAMTS5 genes might play a role in radiation exposure and radioiodine-induced SG changes.

The value of transient ischemic dilation for detecting restenosis after coronary artery revascularization.

AIM: Transient ischemic dilation (TID) is a marker of severe coronary artery disease (CAD). We aimed to assess the incremental value of TID in a cohort of patients with known significant CAD who had recurrence of symptoms after revascularization. METHODS: We identified in our databases 104 patients who had recent coronary revascularization and recurrence of symptoms. 62 patients had PCI (75 arteries) and 42 patients had CABG (104 arteries). All had follow-up stress SPECT MPI and repeat coronary angiography. Myocardial perfusion findings of ischemia and TID were correlated with presence of significant obstructive CAD (>70% stenosis). RESULTS: Follow-up stress Tc-99m Sestamibi SPECT MPI revealed inducible ischemia in 38 patients (36.5%) and TID > 1.20 in 49 patients (47%). Subsequent coronary angiography showed significant obstructive CAD in 44 patients (42%). The sensitivity for detecting obstructive CAD was 61% for SPECT MPI alone, but increased significantly to 93% by the addition of TID as a diagnostic criterion (P < 0.0001). CONCLUSIONS: In this selected patient cohort with prior coronary revascularization, TID is an important marker of obstructive CAD and has incremental value over SPECT MPI alone.

Radioprotective effect of lycopene on the gastrointestinal tract after high-dose radioiodine administration in rat models.

PURPOSE: The aim of this study was to evaluate the effect of lycopene against radioactive iodine (RAI)-related gastrointestinal tract acute damage in a rat model as a novel radioprotective agent. MATERIALS AND METHODS: Twenty Wistar albino rats were divided into two equal groups: group 1 was administered only RAI and group 2 was administered RAI and lycopene. All rats were killed 24 h after the last administration of the agents and the gastrointestinal tract organs were removed surgically for histopathological examination. RESULT: The presence of lamina propria edema in the duodenum (P=0.003) and ileum (P=0.02), ulcer in the duodenum (P=0.033), mucosal erosion in the stomach (P=0.001), mucosal degeneration in stomach (P=0.02) and colon (P=0.02), necrosis in all tissues (P value for stomach=0.005, duodenum=0.001, ileum=0.001, colon=0.001), inflammation in those tissues (P value for; stomach=0.003, duodenum=0.02, ileum=0.011, colon=0.033), and fibrosis in those tissues (P value for; stomach=0.02, duodenum=0.003, ileum=0.003, colon=0.001) were statistically less frequently observed in the lycopene group compared with the RAI group. CONCLUSION: As a first study assessing the protective effect of lycopene on gastrointestinal tract organs in a rat model after RAI, these preliminary basic research findings suggest that lycopene appears to exert radioprotective effects against RAI-induced acute gastrointestinal tract damage.

Coenzyme Q10 for the Protection of Lacrimal Gland against High-Dose Radioiodine Therapy-Associated Oxidative Damage: Histopathologic and Tissue Cytokine Level Assessments in an Animal Model.

PURPOSE: To evaluate protective effect of coenzyme Q10 (CoQ10) in lacrimal glands against high-dose radioactive iodine (RAI)-associated oxidative damage. MATERIALS AND METHODS: Thirty Wistar albino rats were randomly divided into three groups. Group 1 was the control group. Group 2 received 3 mCi/kg RAI via gastric gavage but no medication. Group 3 received 3 mCi/kg RAI via gastric gavage and 30 mg/kg/day CoQ10 intraperitoneally. CoQ10 was started at day one just before RAI administration and continued for five days. Seven days after RAI therapy, the animals were anesthetized and decapitated. Intraorbital (IG), extraorbital (EG), and Harderian (HG) lacrimal glands were removed bilaterally for histopathological and tissue cytokine level assessments. RESULTS: Abnormal lobular pattern, acinar fibrosis, lipofuscin-like accumulations, perivascular infiltration, cell size variation, abnormal cell outlines, irregular nucleus shapes in all lacrimal gland types (p < 0.05 for each), periductal fibrosis, periductal and periacinar fibrosis in EG (p = 0.01, 0.044, respectively) and in HG (p = 0.036, 0.044, respectively), periductal infiltration in HG (p = 0.039) and IG (p = 0.029), acinar atrophy in EG (p = 0.044), and cell shape variation in IG (p = 0.036) were observed more frequently in group 2 than in other groups. RAI caused significant increase in TNF-α, IL-6, nuclear factor kappa B, and total oxidant status, and decrease in IL-2, IL-10, and total antioxidant status levels (p < 0.05 for each). Addition of CoQ10 decreased all cytokine levels, increased nuclear factor kappa B levels more, and increased total antioxidant status levels significantly (p < 0.05 for each). CONCLUSIONS: RAI administration causes prominent inflammatory response in lacrimal glands. Addition of CoQ10 ameliorates the oxidative damage and protects lacrimal glands both in histopathological and tissue cytokine level assessments. Protection of lacrimal glands against oxidative damage may become a new era of CoQ10 use in the future.

Effect of Amifostine on Sperm DNA Fragmentation and Testes after Radioiodine Treatment.

INTRODUCTION: Radioactive iodine (RAI) is commonly used for the treatment of hyperthyroidism caused by Graves' disease or thyroid nodules. However, information available on the impact of RAI therapy on male gonadal function is scarce. This study aimed to determine any possible damage to testicular tissue and sperm quality caused by RAI therapy, and the radioprotective effect of amifostine against such damage. MATERIAL AND METHODS: In total, 36 rats were randomly allocated to three groups, including a control group, RAI group (111 MBq Iodine-131), and RAI + amifostine group (111 MBq Iodine-131 and a single dose of 200 mg/kg amifostine). Blood and epididymal sperm samples were taken for hormone analyses and the evaluation of spermatological parameters. The TUNEL assay and haematoxylin-eosin were used to stain testicular tissue samples to detect histological changes and apoptosis. RESULTS: The groups differed insignificantly for the testicular mass index and spermatozoa concentration. However, spermatozoa motility and percentage of viable spermatozoa were higher in the RAI + amifostine group, compared to the RAI group. Sperm DNA fragmentation and the index of apoptotic germ cells significantly decreased in the amifostine group, in comparison to the radioiodine group. While the testosterone levels showed no significant change, the follicle stimulating hormone (FSH) levels significantly decreased in the RAI + amifostine group. CONCLUSION: All histopathological parameters and some spermatological parameters showed that RAI therapy caused statistically significant damage of testicular tissue and this damage was reduced by amifostine.

The Effect of Omeprazole Usage on the Viability of Random Pattern Skin Flaps in Rats.

BACKGROUND: Necrosis of random pattern flaps caused by inadequate blood flow, especially in the distal part of the flap is one of the biggest challenges in reconstructive surgery. Various agents have been used to prevent flap ischemia. In this study, we used omeprazole, which is a potent inhibitor of gastric acidity to increase flap viability. METHODS: In this study, 35 Wistar-Albino type rats which were divided into 5 equal groups were used. Random-pattern dorsal skin flaps were raised in all groups at seventh day of the study. Group 1 was accepted as control group, and the rats in this group was only given distilled water intraperitoneally for 14 days. Group 2 and group 3 received 10 and 40 mg/kg omeprazole daily for 14 days, respectively. Group 4 and group 5 were given distilled water for the first 7 days and then after the operations they received 10 and 40 mg/kg omeprazole daily for 7 days, respectively. Survival rates of the flaps were examined seventh day after elevation of the flaps by digital imaging and scintigraphy. After assessment of the amount of necrosis, number of vascular structures were counted histopathologically. RESULTS: Percentage of flap necrosis was found to be less in all omeprazole received groups. On digital imaging, percentages of flap necrosis in the study groups were statistically significantly lower than that of the control group (P < 0.001), but there was no significant difference between the study groups (P > 0.05).In the histopathologic specimens, it was detected that the mean number of vessels in proximal (a) and distal (c) portions of the flap in the study groups showed a significant increase when compared with the control group (P < 0.01 for groups 2, 4 and 5, and P < 0.05 for group 3). CONCLUSIONS: In conclusion, possible clinical usage of medications increasing gastrin during flap surgeries can be thought as a positive contributor. In this sense, this study showed that parenteral administration of omeprazole in skin flap surgery increases flap viability possibly by increasing gastrin levels.

Alterations in ADAMTS12 gene expression in salivary glands of radioiodine-131-administered rats.

PURPOSE: The aim of this study was to evaluate the alterations in ADAMTS12 expression after radioiodine-131 (RAI)-induced salivary gland damage. MATERIALS AND METHODS: A total of 30 Wistar male albino rats (260±45 g, 6 months old) were studied for ADAMTS12 gene expression levels and histological changes in the parotid and submandibular salivary glands of rats after the administration of RAI. A series of healthy rats were used as controls. A 3 mCi (111 MBq) dose of RAI was administered to rats in group 1 (n=6), group 2 (n=6), group 3 (n=6), and group 4 (n=6) to induce salivary gland damage. Evaluations were performed at 24 h in controls and at 4, 24 h, 7, and 30 days after the administration of RAI. Quantitative and statistical analyses were carried out. RESULTS: In RAI-administered groups, the mean values of ADAMTS12 gene expression showed a distinct suppression over time for the parotid gland (groups 1-4: 0.38, 0.11, 0.10, and 0.18, respectively; P<0.05), but the values remained similar over time for the submandibular gland (groups 1-4: 1.59, 1.57, 1.03, and 1.00, respectively; P>0.05) compared with the controls. Histological evaluation indicated that RAI-administered groups had significant common nuclear coarsening and focal subnuclear vacuolization, but not in the control samples. Histological changes were more prominent in the parotid gland samples. CONCLUSION: Alterations in ADAMTS12 gene expression may play a role in RAI-induced salivary gland damage in rats.

HEPATOPROTECTIVE EFFECT OF DEXMEDETOMIDINE AGAINST RADIOIODINE TOXICITY IN RATS: EVALUATION OF OXIDATIVE STATUS AND HISTOPATHOLOGICAL CHANGES.

OBJECTIVE AND BACKGROUND: Based on the anti-inflammatory, antioxidant and anti-apoptotic properties of DEX, the present study was conducted to investigate the possible radioprotective effects of DEX against hepatic radioiodine (I-131) toxicity. METHODS: Thirty six rats were randomly divided into three groups as untreated control (group 1); oral radioiodine (RAI, 111 MBq) administrated rats (group 2), and DEX group (oral radioiodine and daily intraperitoneal 25 µg/kg DEX administrated rats-group 3). In the third group, DEX administration was started 2 days before and continued for five days after RAI administration. Twenty-four hours after the administration of the last dose of DEX, liver samples were taken for evaluation of oxidative stress parameters and histopathological changes. RESULTS: The tissue malondialdehyde and advanced oxidation protein product levels in DEX group were significantly lower than RAI group. The total tissue sulphydryl and catalase levels of DEX group were higher than RAI group and the difference was statistically significant. The histopathological damage in the DEX-treated group was significantly less than the damage in the RAI group (p<0.05 for all pathological parameters). Treatment with DEX decreased the histopathological abnormalities when compared with the RAI group. CONCLUSION: It was presented that DEX had radioprotective effect on the liver after I-131 therapy and anti-inflammatory and antioxidant activities are likely to be involved in the mechanism underlying the radioprotective effects of DEX. After further studies, DEX might be used as a hepatoprotective treatment regimen before administering radioactive iodine therapy particularly in patients with hepatic disease.

Scintigraphic Evaluation of the Stump Region After Extremity Amputation and the Effect of Scintigraphy on Treatment.

BACKGROUND: We evaluated the stump region with scintigraphy and compared the correlation of treatment modalities and scintigraphic results. METHODS: Sixty-eight cases with extremity amputation were included in the study. Amputation applied cases underwent four-phase Tc-99m hydroxymethylene diphosphonate scintigraphy. Groups were performed according to the scanning time after amputation and amputation regions. After scintigraphic evaluation, results were recorded into five groups: osteomyelitis, soft-tissue infection, reactive changes secondary to surgery, chronic osteomyelitis, and normal. Post-surgical treatment modalities of the patients were determined and compared with scintigraphic results. RESULTS: In the scintigraphic evaluation of stump regions of the 68 amputated cases, 34 patients had acute osteomyelitis, one had chronic osteomyelitis, 16 had soft-tissue infection, and eight had changes secondary to the surgery. Nine of 68 cases had normal scintigraphic features. In the scintigraphic evaluation, 43 patients took antibiotic treatment and 16 had surgery. There was a strong correlation between scintigraphic results and treatment approach (P < 0.0001, r = 0.803) by means of preferred therapy and effectiveness of the therapy according to the scintigraphic results. Scintigraphy need increases with age after amputation and a negative correlation between patient age and scintigraphic need was found (P < 0.02, r = -0.339). There was no pathology in the follow-up in the cases that were scintigraphically normal. CONCLUSION: Bone scintigraphy is a cost-effective, non-invasive, and efficient method that directs treatment in the evaluation of the stump region after amputation.

Prevalence of Helicobacter Pylori Infection in School and Pre-School Aged Children with C-14 Urea Breath Test and the Association with Familial and Environmental Factors.

OBJECTIVE: To investigate the prevalence of Helicobacter pylori (Hp) infection in pre-school and school age children with C-14 urea breath test, and to explore its association with age and socioeconomic factors in Turkey. METHODS: Hp infection status was determined by using Urea Breath Test (UBT). Patients who had previous gastric surgery, Hp eradication treatment or equivocal UBT results were excluded. A questionnaire was administered to elicit information on gender, age, ABO/Rh blood group type, presence of gastric disease in the family, domestic animal in the household, and treatment for idiopathic Iron Deficiency Anemia (IDA). RESULTS: This retrospective study included 500 pediatric patients (179 boys, 321 girls, mean age 10.7±4.3 years) of whom 62 (12.4%) were aged ≤6 years and 438 (87.6%) were aged 7 to 16 years. Helicobacter pylori (Hp) was positive in 245 (49%) cases. In the pre-school age group, 21/62 cases (34%) had positive UBT while in the school age group 224/438 children (51%) had positive UBT. A family history of dyspepsia and pet ownership were not associated with Hp positivity. Hp positive 76 (29.8%) children were on IDA treatment but this was not statistically significant. CONCLUSION: The Hp infection positivity rate was 49% in the pediatric age study group. The positivity rate was significantly lower at preschool age than school age, and it increased with age. There was no association with gender, ABO/Rh blood groups, presence of domestic pets, IDA, or history of gastric disease in the family.

[An evaluation of the radioprotective effect of vitamin E on the salivary glands of radioactive iodine in rats]. / Radyoaktif iyot verilen siçanlarda tükürük bezleri üzerinde E vitaminin radyasyondan koruyucu etkisinin degerlendirilmesi.

OBJECTIVES: This study aims to examine the acute effect of vitamin E on salivary gland of radioactive iodine (RAI; 131I)-induced rats and to evaluate whether vitamin E have a radioprotective effect. MATERIALS AND METHODS: Sixteen Wistar albino rats were used in the study. The rats were divided into two groups. The first group was administered (131)I orally and 1 ml physiological saline. The second group was administered (131)I and 1 ml vitamin E intraperitoneally. Vitamin E was started two days before the RAI therapy and continued for seven days. On the eighth day, salivary glands were removed and evaluated histopathologically. RESULTS: There was no statistically significant difference between the groups. The changes in the interstitial space of all glands and in acinar epithelial cells of parotid and sublingual glands were observed in a lower number of the rats of vitamin E group, compared to the controls. Except panacinar inflammation, histopathological changes in acinar epithelial cells of the submandibular gland were noticed in a lower number of the rats of vitamin E group. CONCLUSION: Considering the changes in the interstitial space and acinar epithelial cells in a lower number of the rats of vitamin E group, we conclude that vitamin E may have protective effects for interstitial space of all glands and acinar epithelial cells of the parotid and sublingual glands during the acute period.

An incidental detection of aortic aneurysm on Tc-99m MAG3 renal scintigraphy.

A 71-year-old man with newly diagnosed hypertension was referred for Technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) renal scintigraphy to evaluate the recent onset of impairment in renal functions. Dynamic imaging revealed activity flow which was suspicious for aortic aneurysm (AA) with a concurrent decrease in left renal blood flow. CT angiography of the thoracoabdominal aorta confirmed that this area corresponded to AA. The purpose of this report was to present the first case of incidental detection of AA on Tc-99m MAG3 scintigraphy and highlight the importance of correlative imaging for the diagnosis of abnormal radioactivity accumulation in the region of vascular structures.

Incidentally detected diaphragmatic hernia mimicking angina pectoris with Tc-99m MIBI myocardial perfusion imaging.

In recent years (99m)Technetium methoxy-isobutyl-isonitrile ((99m)Tc MIBI) is widely used in the evaluation of myocardial perfusion imaging (MPI). In this imaging protocol besides the cardiac evaluation, numerous other organs are included in the field of view. (99m)Technetium MIBI is taken up in all metabolically active tissue in the body except for the brain. Extracardiac uptake patterns as benign or serious conditions can be revealed during the MPI. In the imaging protocol, we should be aware of distribution of this radiotracer in order to recognize the abnormal uptake. Here in, we present a large diaphragmatic hernia, seemed as a mirror vision of myocardium that was determined incidentally during the MPI with (99m)Tc MIBI.

Diffuse Myocardial Uptake of (99m)Tc-HDP in Multiple Myeloma.

Soft tissue uptake is a rare finding in bone scintigraphy, with an incidence of 2%. Although the mechanism has not yet been fully clarified, several causes have been reported for this unusual uptake pattern. This paper presents a case of diffuse myocardial accumulation of technetium-99m hydroxymethylene diphosphonate ((99m)Tc-HDP) without either solid/visceral organ or soft tissue with multiple myeloma (MM) in skeletal scintigraphy. A 93-year-old man with hypertension and chronic heart failure for 14 years underwent bone scanning due to a 2-month history of back pain within a 1-year period of MM. Three hours later, (99m)Tc-HDP late static images showed diffuse myocardial radiotracer accumulation and there were no other sites of abnormal soft tissue or visceral uptake. Myocardial accumulation had disappeared on 24-h delayed static images. This accumulation was thought to be related with AL-type amyloidosis associated with MM.