18F-FDG PET/CT imaging of IgG4-producing MALT lymphoma with multiple site involvement.

18F-FDG PET/CT is regarded as a modality utilized for the purpose of lesion localization, staging and assessment of treatment response in patients with lymphoma. However, it is difficult that we diagnose among multifocal lymphoma, IgG4-related disease (IgG4-RD), or a combination of both conditions when confronted with multiple sites of 18F-FDG uptake with heightened serum IgG4 levels. We present a case of a 72-year-old male who was suspected of Sjögren's syndrome based on symptoms of xerostomia accompanied by swelling of the bilateral upper eyelid and salivary glands. Following a diagnostic biopsy that revealed mucosa-associated lymphoid tissue (MALT) lymphoma as a possible finding, 18F-FDG PET/CT was conducted, which demonstrated multiple sites of 18F-FDG accumulation. While multifocal MALT lymphoma was initially suspected, the coexistence of IgG4-RD could not be definitively ruled out due to the elevated serum IgG4 levels. Subsequent histopathological and immunohistochemical examinations confirmed the diagnosis of IgG4-producing MALT lymphoma. After receiving systemic therapy with rituximab, the swelling of the bilateral upper eyelid and parotid glands resolved upon visual examination, and the serum IgG4 levels returned to within the normal range in a few months. No new lesions were detected during the subsequent follow-up examinations conducted over a period of 3 years.

Effectiveness of 18F-FDG PET/CT in finding lung metastasis from a retroperitoneal paraganglioma.

A 50-year-old woman was diagnosed with iron deficiency anemia on general medical examination. Further, contrast-enhanced abdominal CT and magnetic resonance imaging revealed a large hypervascular mass with internal degeneration and necrosis in the retroperitoneal space. She was referred to our hospital for further evaluation and treatment. Because the paraganglioma was most likely as the imaging diagnosis, 123I-MIBG scintigraphy was performed. It revealed the marked abnormal accumulation in the retroperitoneal lesion indicating the paraganglioma and no other abnormal accumulation was noted. Several plasma catecholamines and their urinary metabolites were normal. On the subsequent 18F-FDG PET/CT, high FDG uptake was found in the retroperitoneal lesion (SUVmax=38). FDG uptake was also found in a small nodule at the base of the lower lobe of the right lung (SUVmax= 9.8). Contrast-enhanced imaging revealed a hypervascular nodule at the base of the right lung, suggesting pulmonary metastasis of a paraganglioma. The abdominal lesion and right lung nodule were excised, and retroperitoneal paraganglioma and pulmonary metastasis were diagnosed based on the pathology findings. In this case, 18F-FDG PET/CT was useful in the search for paraganglioma metastasis. We report a relationship between 123I-MIBG accumulation and 18F-FDG uptake in paraganglioma and review the relevant literature.

Unilateral axillary lymph node fluorodeoxyglucose uptakes after coronavirus disease 2019 vaccination.

Vaccination against coronavirus disease 2019 (COVID-19) started in early December 2020 worldwide, and healthcare workers in Japan were vaccinated in February 2021. We encountered three patients who underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for cancer screening at our institution, showing FDG uptakes in the axillary lymph nodes, which seemed to be reactive changes. Two of them were males in their 40s and one was a female in her 50s; all of them were healthcare workers. The medical history revealed that they received the Pfizer-BioNTech COVID-19 vaccination twice at their left shoulders before the FDG PET/CT examination. The degree of FDG uptakes were maximum standardized uptake value (SUVmax)=3.2-9.9, SUVmax=5.9-10.3, and SUVmax=2.8-7.9, respectively. They were diagnosed with reactive lymph nodes because of vaccination owing to the absence of abnormal FDG PET/CT findings at other sites. As COVID-19 vaccination becomes more widespread in Japan, radiologists should be aware of these findings to avoid misdiagnosis of FDG uptakes in pathological lymph nodes and to prevent unnecessary additional examinations. Recently, similar FDG PET/CT findings have been reported after receiving the COVID-19 vaccination, and we will report it with a literature review.

Multimodal imaging of cardiac-calcified amorphous tumor.

Cardiac-calcified amorphous tumor (CAT) is a rare non-neoplastic tumor and its origin and pathogenesis are still unclear. In addition, it is difficult to clinically diagnose as cardiac CAT without pathological findings. We present a case of a 78-year-male diagnosed with cardiac CAT after surgical resection. We could evaluate tumor aspects by multimodal imaging including echocardiography, contrast-enhanced computed tomography (CT), magnetic resonance image, and 18F-fluorodeoxyglucose-positron emission tomography/CT before surgery.

Marked accumulation of fluorodeoxyglucose and inflammatory cells expressing glucose transporter-3 in immunoglobulin G4-related autoimmune hepatitis.

Immunoglobulin (Ig)G4-related autoimmune hepatitis (AIH) is a recently proposed subtype that responds well to steroid treatment; however, its pathogenesis remains unclear. We report here a 65-year-old Japanese woman with skin itching and lip swelling. She had liver injury with jaundice, which persisted despite stopping anti-allergic agents. Blood chemistry revealed highly elevated serum IgG and IgG4 (535 mg/dL) levels, and positive anti-nuclear antibody. The diagnosis of AIH was based on liver biopsy. Notably, the IgG4+ /IgG+ cell ratio was 85%. On fluorodeoxyglucose (FDG) positron emission tomography/computed tomography, robust signal intensity was found in the liver, and in enlarged lymph nodes and salivary glands with confirmed IgG4+ cell infiltration. Immunofluorescence analysis of the liver biopsy specimen indicated clear expression of glucose transporter-3 (Glut-3) in IgG4+ inflammatory cells infiltrating into the portal area. This is the first report of simultaneous strong accumulation of FDG and Glut-3 expression in IgG4-related AIH, which might aid in elucidating the pathogenesis of this disease.

Clinical significance of patterns of increased [18F]-FDG uptake in the thyroid gland: a pictorial review.

In the diagnosis and staging of oncologic patients, [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) is well recognized as an important functional imaging modality. FDG-PET also has been used for cancer screening in healthy individuals. In general, the normal thyroid gland shows absent or low uptake on FDG-PET, which is often identified as an incidental finding on PET. Today, thyroid FDG uptake can be seen in three patterns: diffuse; focal; and diffuse-plus-focal. Diffuse thyroid uptake is mainly considered an indicator of chronic thyroiditis. Focal thyroid uptake has been associated with malignancy (range 25-50%). Diffuse-plus-focal uptake is not well recognized and might also indicate a risk of malignancy. Understanding the patterns of thyroid FDG uptake is thus important for nuclear medicine physicians or radiologists when giving recommendations to the referring physician. In this pictorial review, we show the clinical significance of different patterns of thyroid uptake on FDG-PET [PET/computed tomography (CT)], including ultrasonography (US) findings.

Clinical spectrum and diagnostic pitfalls of multiple abnormal uptakes on bone scintigraphy.

Bone scintigraphy with technetium-99m (99mTc)-labeled diphosphonates is one of the most frequently performed radionuclide procedures. Accumulation of 99mTc-labeled diphosphonate is well recognized to reflect conditions of accelerated bone turnover and metabolism. Therefore, it is a functional imaging modality for detecting metastatic bone tumors, metabolic bone disease, traumatic injury, and inflammation. This pictorial essay describes the possible patterns of distribution of abnormal uptake for differential diagnosis of metastatic bone tumor, as well as the diagnostic pitfalls of bone scintigraphy.

Molecular biological correlation of fluorine-18 fluorodeoxyglucose uptake in esophageal squamous cell carcinoma.

OBJECTIVE: The aim of this study was to assess the relationship between fluorine-18 fluorodeoxyglucose (F-FDG) uptake and molecular biological markers in esophageal squamous cell carcinoma (ESCC) patients. METHODS: Our patient population included 51 patients who underwent F-FDG PET/computed tomography before surgery. Excised tumor tissue was analyzed immunohistochemically using monoclonal antibodies for glucose transporter-1 (GLUT-1), GLUT-3, CD34 [microvessel density (MVD) marker], CD68 (macrophage marker), and CD163 (tumor-associated macrophage marker). The relationships among pathological factors [pathological T stage (p-T stage), pathological lymph node status (p-N status), pathological stage (p-stage), and pathological tumor length], the maximum standardized uptake value (SUVmax), and these molecular biological markers were evaluated using Spearman's rank test and the Kruskal-Wallis test. RESULTS: GLUT-1, GLUT-3, CD34, and CD163 significantly correlated with SUVmax (r=0.547, P<0.001 for GLUT-1; r=0.569, P<0.001 for GLUT-3; r=0.463, P=0.001 for CD34, r=0.455, P=0.001 for CD163), whereas SUVmax, GLUT-1, GLUT-3, CD34, and CD163 significantly correlated with p-T stage (r=0.552, P<0.001 for SUVmax, r=0.307, P=0.03 for GLUT-1, r=0.349, P=0.013 for GLUT-3, r=0.313, P=0.027 for CD34, r=0.526 for CD163, P<0.001), but not with p-N status. CD68 levels showed no significant correlation with SUVmax, p-T stage, p-stage, or p-N status. CONCLUSION: SUVmax, GLUT-1 expression, GLUT-3 expression, MVD, and TAMs show a relationship with the tumor stage and extent of ESCC. GLUT-1, GLUT-3, MVD, and TAMs are associated with the mechanism of F-FDG uptake in ESCC.

Assessment of cell proliferation in renal cell carcinoma using dual-phase 18F-fluorodeoxyglucose PET/CT.

The present study aimed to examine the association between 18F-fluorodeoxyglucose (18F-FDG) uptake and cell proliferation markers; in addition, the correlation between 18F-FDG uptake and biological characteristic in patients with renal cell carcinoma (RCC) was investigated using dual-phase 18F-FDG-positron emission tomography/computed tomography (PET/CT). Dual-phase 18F-FDG PET/CT was performed on 31 RCC patients and the maximum standardized uptake values at 1 h (SUV1) and 2 h (SUV2) as well as the retention index (RI; %) in the primary tumors were calculated. Monoclonal antibodies for Ki-67, minichromosome maintenance 2 (MCM2) and topoisomerase II α (topo II α) were used to assess the expression levels of their respective proteins in excised tumor tissue using immunohistochemistry. The results demonstrated that RI and SUV2 in patients with Stage I/II + grade 1 (G1) RCC were significantly decreased compared with all patients with other stages/grades (RI, P=0.0065; SUV2, P=0.043); in addition, significantly increased uptake and RI were detected in patients with metastases compared with patients without metastases (SUV1, P=0.029; SUV2, P=0.0003; RI, P<0.001). All proliferation markers significantly correlated with RI (Ki-67, r=0.501, P=0.004; MCM2, r=0.359, P=0.047; topo II α, r=0.402, P=0.024), while SUV1 and SUV2 correlated with Ki-67 only. In conclusion, the results of the present study demonstrated that dual-phase 18F-FDG-PET/CT was more useful for predicting cell proliferation in RCC compared with single-phase imaging alone. However, follow-ups are required in order to determine whether dual-phase 18F-FDG-PET/CT provides independent prognostic information.

¹8F-FDG PET/CT and contrast enhanced CT in differential diagnosis between leiomyoma and gastrointestinal stromal tumor.

In a 49 years old woman a large abdominal tumor was diagnosed by abdominal ultrasound. Dynamic contrast-enhanced computed tomography (CECT) showed a large tumor with minute calcification and poor contrast enhancement in the left abdominal cavity. The fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (¹8F-FDG PET/CT) scan showed low ¹8F-FDG uptake in the tumor. The SUV max (early image) was 1.90, and that of the delayed image was 2.86. A gastrointestinal stromal tumor (GIST) was suspected. Tumor resection revealed that it was a leiomyoma originating in the major curvature of the stomach. In conclusion, the findings of low ¹8F-FDG uptake on ¹8F-FDG PET and poor contrast enhancement on CECT in a gastric submucosal tumor suggested of a gastric leiomyoma rather than GIST.

Assessment of 99mTc-MIBI SPECT(/CT) to monitor multidrug resistance-related proteins and apoptosis-related proteins in patients with ovarian cancer: a preliminary study.

OBJECTIVE: Multidrug resistance (MDR) has been suggested to be a major cause of failure of chemotherapy treatment for cancer. It is associated with the expression of MDR-related and apoptosis-related proteins. Recently, technetium-99m hexakis 2-methoxyisobutylisonitrile ((99m)Tc-MIBI) has been suggested as a tumor-seeking agent for the detection of MDR. The aim of this study was to evaluate (99m)Tc-MIBI single-photon emission computed tomography (SPECT)(/CT) for functional imaging of MDR-related and apoptosis-related proteins in patients with ovarian cancer. METHODS: Eleven women (mean age 63 years, range 53-76) with a clinical suspicion of ovarian cancer were prospectively studied. All patients were examined with (99m)Tc-MIBI imaging before surgery. After intravenous injection of 740 MBq (99m)Tc-MIBI, SPECT(/CT) imaging at 10 min and 2 h was performed. Based on the semiquantitative analysis of (99m)Tc-MIBI SPECT(/CT), both early and delayed tumor uptake ratios and washout rate % were calculated. The expression of MDR-related and apoptosis-related proteins was assessed in surgically excised tumors. Immunohistochemical staining was performed to quantify the expression levels of multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein1 (MRP1), MRP3, lung resistance protein (LRP), breast cancer resistance protein (BCRP), Y-box-binding protein-1 (YB-1), Bcl-2, Bax and glutathione-S-transferase. (99m)Tc-MIBI imaging results and immunohistochemical results were compared. RESULTS: Laparotomy was performed in all patients. Six ovarian cancers were proven by histopathological examination. Five of the six ovarian cancers were positive for (99m)Tc-MIBI uptake on both early and delayed images with (99m)Tc-MIBI SPECT(/CT). MDR-related and apoptosis-related proteins were found to be expressed in all tumors. For the five positive (99m)Tc-MIBI uptake cases, the washout rate % of (99m)Tc-MIBI uptake showed a significant positive correlation with the expression of YB-1 (r = 0.988, P = 0.0015), and the early tumor uptake ratio showed a significant positive correlation with the expression of Bax (r = 0.882, P = 0.047). CONCLUSIONS: Our results suggested that (99m)Tc-MIBI SPECT(/CT) might be a valuable diagnostic imaging technique to evaluate MDR-associated YB-1 and Bax-mediated apoptosis in patients with ovarian cancer.

Hypermetabolic pulmonary and bone marrow lesions in a patient with chronic adult T-cell leukemia.

A 69 years old woman with adult T-cell leukemia (ATL) (chronic type) was referred for a fluorine-18 fluorodeoxyglucose positron emission computed tomography ((18)F-FDG PET/CT). Multiple hypermetabolic pulmonary and bone lesions were evidence. The patient underwent chemotherapy, but did not respond, and she died approximately 8 months from the onset of symptoms. Autopsy showed ATL cells infiltrating the lung parenchyma and the pulmonary hilum. In conclusion, we present a case of hypermetabolic pulmonary lesions associated with thoracic CT findings on a (18)F-FDG PET/CT scan in a patient with a chronic adult T-cell leukemia.

Relationship between 2-deoxy-2-[(18)F]-fluoro-d-glucose uptake and clinicopathological factors in patients with diffuse large B-cell lymphoma.

The aim of this study was to investigate correlations between the standardized uptake value of the biopsy site (BSUVmax) and levels of glucose transporter (GLUT)-1, GLUT-3 and hexokinase-II (HK-II), between BSUVmax and the Ki-67 proliferation index (MIB-1), and between BSUVmax and clinicopathological factors. Sixty-eight patients with diffuse large B-cell lymphoma (DLBCL) were included in this study. BSUVmax was significantly correlated with GLUT-1, GLUT-3 and the International Prognostic Index (IPI) (GLUT-1: r = 0.584, IPI: r = 0.363, p < 0.001; GLUT-3: r = 0.369, p = 0.009; IPI: r = 0.363, p = 0.004), but not with MIB-1 and HK-II. A statistically significant correlation was observed between GLUT-3 expression and each of IPI and gene expression profiling (GEP) (IPI: p = 0.0186; GEP: p = 0.0179). 2-Deoxy-2-[(18)F]-fluoro-d-glucose (FDG) uptake was significantly correlated with the levels of GLUT-1 and GLUT-3 and with IPI. The results indicated that GLUT-3 expression is related to GEP and IPI, and that BSUVmax and GLUT-3 may have a relationship with the prognosis of DLBCL.

The difference in relationship between 18F-FDG uptake and clinicopathological factors on thyroid, esophageal, and lung cancers.

OBJECTIVES: The aim of this study was to reveal the differences in clinicopathological factors affecting maximum standardized uptake value (SUVmax) between esophageal squamous cell carcinoma (ESCC), non-small-cell lung cancer (NSCLC), and papillary thyroid cancer (PTC). METHODS: This study consisted of 119 patients with ESCC (n=43), PTC (n=40), or NSCLC (n=36). We investigated the correlations between SUVmax and clinicopathological factors by using Spearman's correlation coefficient and the Kruskal-Wallis test. Multiple regression analysis was used to investigate which clinicopathological factors significantly affected SUVmax in each cancer type. RESULTS: The SUVmax correlated with glucose transporter-1 (GLUT-1) expression in NSCLC (r=0.536, P=0.007) and ESCC (r=0.597, P<0.001) but not in PTC. The SUVmax correlated with Ki-67 expression in NSCLC (r=0.381, P=0.022) and PTC (r=0.374, P=0.017) but not in ESCC. A high SUVmax was correlated with a higher pathological T stage (p-T stage) in NSCLC (r=0.536) and ESCC (r=0.597, both P<0.001) but not in PTC. An elevated SUVmax was significantly associated with pathological lymph node status (p-N) in NSCLC, but not in ESCC and PTC. In multiple regression analysis, p-T stage and GLUT-1 expression were statistically significant factors in ESCC, and p-T stage was a statistically significant factor in NSCLC. In PTC, Ki-67 showed a statistically significant association with SUVmax. CONCLUSION: SUVmax in NSCLC depended on the tumor invasion area; SUVmax in ESCC depended on tumor depth and GLUT-1 expression; and SUVmax in PTC might be associated with cell proliferation. The biological factors affecting SUVmax differ according to tumor type.

The relationship between 18F-FDG metabolic volumetric parameters and clinicopathological factors of breast cancer.

OBJECTIVES: This study was conducted to evaluate the relationship between fluorine-18 fluorodeoxyglucose metabolic parameters [maximum standardized uptake value (SUV(max)), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)] and clinicopathological factors of breast cancer. METHODS: The study comprised 93 patients. A volumetric region of interest was drawn over the abnormal focal uptake of breast cancer. Spearman's rank correlation, the Kruskal-Wallis test, and receiver operating characteristic analysis were used to investigate the relationship between clinicopathological factors and metabolic parameters and determine which metabolic parameters were most highly associated with clinicopathological factors. RESULTS: All parameters had a statistically significant relationship with pathological T stage (p-T stage), pathological N status (p-N status), pathological stage (p-stage), and triple-negative type (TN) (all P values were <0.05). There were statistically significant differences between SUV(max) and TLG in relation to lymphatic invasion, estrogen receptor, and nuclear grade (P<0.05). High MTV showed a tendency toward association with estrogen receptor negativity, but the relation did not reach the level of statistical significance (P=0.056). No statistically significant relationship was observed between MTV and lymphatic invasion or nuclear grade. In the receiver operating characteristic analysis of p-T stage and p-stage, the AUC for TLG was significantly larger than that for SUV(max) (P=0.0003 and 0.048, respectively). There were marginally significant differences between TLG and MTV in relation to p-stage (P=0.058). CONCLUSION: TLG may reflect tumor metabolism for clinicopathological factors of breast cancer better than SUV(max) or MTV.

Assessment of atherosclerosis in oncologic patients using ¹8F-fluoride PET/CT.

OBJECTIVES: The purpose of this study was to evaluate the prevalence, distribution, and relationship of (18)F-fluoride uptake and arterial calcification in oncologic patients using (18)F-fluoride PET/CT. METHODS: Image data obtained from 29 oncologic patients undergoing whole-body (18)F-fluoride PET/CT were evaluated retrospectively. Arterial wall (18)F-fluoride uptake and calcification were analyzed both quantitatively and semiquantitatively in 8 patients with arterial (18)F-fluoride uptake. RESULTS: Arterial (18)F-fluoride uptake was observed at 35 lesions in 8 (28 %) of the 29 patients, and calcification was observed at 345 lesions in the same patients. Five of the 8 patients had prostate cancer, and the remaining patients had hepatocellular carcinoma or malignant melanoma. In these 8 patients, the prevalence of both (18)F-fluoride uptake and calcification was highest in the abdominal aorta, followed by the descending thoracic aorta and the aortic arch. Colocalization of radiotracer accumulation and calcification could be observed in the 32 lesions (91 %) with arterial (18)F-fluoride uptake, and only the 3 lesions (9 %) with arterial (18)F-fluoride uptake were not colocalized with arterial calcification. The presence of both arterial radiotracer uptake and calcification was significantly associated with advancing age (P < 0.01). CONCLUSION: Our results suggest that (18)F-fluoride PET/CT might be a useful modality for detecting active mineral deposition sites of atherosclerosis in oncologic patients.

Incidental detection of rare mesenteric inflammatory pseudotumor by (18)F-FDG PET.

A 60 years old asymptomatic male underwent fluorine-18 fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) for his medical check-up, and abnormal (18)F-FDG uptake was observed in the retroperitoneum. The maximum standardized uptake value (SUV (max)) was 5.2. Based on CT, MRI and (18)F-FDG PET findings, the differential diagnosis included specific or non-specific inflammatory change, malignant lymphoma, trauma, gastrointestinal stromal tumor and soft-tissue sarcoma. Tumor resection was performed, and the histopathological finding was an inflammatory pseudotumor (IPT) originating at the mesentery in the retropetonium. After two years and eight months from his initial operation, recurrent IPT was detected by (18)F-FDG PET for follow-up, although he was asymptomatic. The IPT could be of traumatic origin since the patient suffered a severe abdominal trauma 6 months before. A mesenteric IPT is very rare, and to our knowledge, this is the first case report of (18)F-FDG PET detecting a mesenteric IPT. In conclusion, when abnormal high (18)F-FDG uptake is observed in the mesentery incidentally in clinical routine examination, IPT should be included as one of the differential diagnoses. (18)F-FDG may be useful in detecting local recurrence and follow-up after operation.

Prognostic significance of total lesion glycolysis in patients with advanced non-small cell lung cancer receiving chemotherapy.

BACKGROUND: [¹8F]fluorodeoxyglucose positron emission tomography (FDG-PET) imaging has been employed as a non-invasive diagnostic tool for malignant tumors. Total lesion glycolysis (TLG) on FDG-PET is calculated by multiplying the mean standardized uptake value (SUVmean) by the tumor volume. Unlike the maximum standardized uptake value (SUVmax), which represents the point of greatest metabolic activity within tumors, TLG has been suggested to reflect global metabolic activity in whole tumors. METHODS: We retrospectively examined whether or not FDG-PET measurements, including SUVmean, SUVmax, and TLG, could predict progression-free survival (PFS) or overall survival (OS) in patients with non-small cell lung cancer (NSCLC) receiving chemotherapy. RESULTS: This study involved 81 consecutive patients with NSCLC who received chemotherapy. All of the patients underwent FDG-PET examination before treatment. SUVmean, SUVmax, and TLG on FDG-PET were significantly associated with gender, smoking status, and tumor histology. With adjustment for several other variables, Cox regression analysis showed that TLG was significantly prognostic for both PFS [hazard ratio=2.34; 95% confidence interval, 1.18-4.64; P=0.015] and OS (hazard ratio=2.80; 95% confidence interval, 1.12-6.96; P=0.003), whereas SUVmean and SUVmax had no significant association with PFS (P=0.693 and P=0.322, respectively) or OS (P=0.587 and P=0.214, respectively). CONCLUSIONS: Our findings suggest that TLG may be more useful than SUVmean and SUVmax for predicting PFS and OS in NSCLC patients receiving chemotherapy. The TLG measurement on FDG-PET imaging could be routinely recommended to advanced NSCLC patients.