Evaluating therapeutic efficacy of extended shelf-life 90 Y glass microspheres in transarterial radioembolization for colorectal cancer: a quantitative FDG PET/CT analysis.

OBJECTIVES: There is a lack of sufficient evidence regarding the use of extended shelf-life (ExSL) Yttrium-90 ( 90 Y) glass radiomicrospheres in metastatic colorectal cancer (mCRC) patients. We aimed to investigate the efficacy of ExSL 90 Y glass radiomicrospheres with a personalized treatment approach by analyzing 18 F-FDG PET/CT quantitative parameters [metabolic tumor volume (MTV) and total lesion glycolysis (TLG)] separately before and after the treatment. METHODS: A total of 93 radioembolization sessions involving 77 patients were included. Simplicit 90 Y software was utilized to perform multicompartmental voxel-based dosimetry. Adverse events were recorded using the CTCAE v5.0 criteria. The survival data were recorded in detail. RESULTS: The overall disease control rate was 84.9%, with a median overall survival (OS) of 12.7 months and median progression-free survival (PFS) of 8.3 months. A statistically significant increase in treatment response rate was observed when there was an increase in absorbed tumor dose for pre-treatment unit MTV ( P  = 0.005) and TLG ( P  = 0.004) values. We didn't observe any additional side effects/vital risks that could be considered clinically significant. CONCLUSION: Our study has provided evidence on the therapeutic effectiveness and safety in terms of dose-toxicity profile of ExSL 90 Y glass microspheres in a large cohort of mCRC patients. With a personalized treatment approach, the increase in radiation dose absorbed by the tumor has shown a significant contribution to treatment response rate, as indicated by quantitative measurements obtained through 18 F-FDG PET/CT.

Bone Lipogranuloma Mimicking Metastatic Disease on 18F-FDG PET/CT.

ABSTRACT: Primary bone lipogranuloma is an extremely rare disease associated with reactive inflammatory granulomatous reaction associated with exogenous or endogenous lipids. Herein, we report a case of bone lipogranuloma with intense 18F-FDG uptake, which mimics metastatic disease on 18F-FDG PET/CT in a patient with breast cancer.

Prognostic significance of 18F-FDG PET/CT indices in metastatic renal cell cancer and evaluation of revised IMDC risk model by including 18F-FDG PET-CT parameters.

BACKGROUND: Prognostic markers in metastatic renal cell cancer (mRCC) are still insufficient. Any prognostic model objectively determines disease burden. PURPOSE: To investigate the relationship between 18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) parameters and outcomes in mRCC, and to define a revised International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model for the intermediate-risk group. MATERIAL AND METHODS: A retrospective study of mRCC was conducted. To investigate the prognostic significance of 18F-FDG PET/CT parameters, maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), and metabolic tumor volume (MTV) were determined in pre-treatment images. Cutoff values were defined by ROC curve analyses and their association with outcomes was analyzed. Additionally, a TLG-adjusted IMDC model was created by stratifying intermediate-risk group patients according to TLG levels. RESULTS: The study included 52 patients. The disease control rate (DCR) was 61.5% and median overall survival (OS) was 18 months (95% confidence interval=9.2-25.8). In the univariate analyses, IMDC score, MTV, and TLG were prognostic factors for Disease Control Rate (DCR), and Eastern Cooperative Oncology Group (ECOG)-Performance Status (PS), IMDC score, lactate dehydrogenase (LDH), treatment option, MTV, and TLG were prognostic factors for OS (P < 0.05 each). In the multivariate analyses, MTV was an independent prognostic factor for DCR, and ECOG-PS, LDH, IMDC score, and TLG were independent prognostic factors for OS. According to the revised-IMDC model, the intermediate-favorable group showed longer OS than the intermediate-unfavorable group. CONCLUSION: Pretreatment MTV was independent prognostic factor for DCR and ECOG-PS, LDH, IMDC score, and TLG were independent prognostic factors for OS. Revised-IMDC model could identify patients with a worse prognosis among the IMDC intermediate-risk group.

Extranodal NK/T-Cell Lymphoma With Widespread Cutaneous and Subcutaneous Involvement on 18 F-FDG PET/CT.

ABSTRACT: Nasal-type extranodal natural killer/T-cell lymphoma is an aggressive rare type of lymphoma that mostly affects the nasal cavity and adjacent areas. However, some patients can present with distant nodal or extranodal involvement including the Waldeyer ring, gastrointestinal tract, genitourinary organs, lung, thyroid, skin, or adrenal glands. Herein, we present a unique case of extranodal natural killer/T-cell lymphoma with widespread cutaneous and subcutaneous involvement on 18 F-FDG PET/CT.

The value of parathyroid scintigraphy on lesion detection in patients with normocalcemic primary hyperparathyroidism.

OBJECTIVE: Primary hyperparathyroidism (PHPT) is one of the most frequent endocrine diseases. Most of the patients with PHPT are asymptomatic, and only 20% of them become symptomatic with increasing levels of calcium. It has been reported that normocalcemic primary hyperparathyroidism (NPHPT) may be the incipient period of PHPT where calcium (Ca) levels are in normal range, and it may advance to overt PHPT. Early diagnosis of PHPT is important in order to prevent its complications. In this retrospective study, we aimed to evaluate the role of 99mTc-MIBI parathyroid scintigraphy on lesion detection in patients with NPHPT. MATERIAL AND METHODS: The parathyroid scintigraphy database was reviewed retrospectively in patients with PHPT. 117 patients who underwent 99mTc-MIBI scintigraphy were recruited to the study. Serum calcium level above 10.5mg/dl was considered as hypercalcemia. RESULTS: A total of 117 patients (female/male:98/19) mean serum PTH levels (mean±SD) were 149±97pg/ml in normocalcemic group (Ca:9.6±0.6mg/dl, n:38) and 189±135pg/ml in hypercalcemic group (Ca:11.4±0.6mg/dl, n:79) (p:0.072). The sex and ages were not different between the scintigraphy positive and negative groups, but the lesion detection rates with parathyroid scintigraphy were 42% in normocalcemic group and 81% in hypercalcemic group (p<0.0001). CONCLUSIONS: Several factors including serum Ca, the imaging protocol, existence of multiglandular disease, the size and MIBI biokinetics of the adenoma may influence lesion detectability in parathyroid scintigraphy. Although high serum Ca level is an important parameter in predicting its success, parathyroid scintigraphy remains a valuable diagnostic method even in patients with NPHPT.

Hybrid Renal Cortical Imaging with Single Photon Emission Computerized Tomography/Computed Tomography in a Pediatric Patient with Severe Caudal Regression Syndrome.

Caudal regression syndrome (CRS) or sacral agenesis is a rarely seen malformation with a varying degree of structural abnormalities, including multiorgan system dysfunctions, reported with higher incidence among children of mothers with diabetes, as in this case. Spinal anomalies can range from coccyx hemiagenesis to the total absence of lower lumbar vertebrae and sacrum in most severe cases. Herein, we have presented a 9-year-old patient with CRS who had renal failure. Technetium-99m dimercaptosuccinic acid renal scintigraphy revealed bilaterally non-functioning kidneys with no renal cortical uptake. Renal anomalies in CRS with vertebral, anorectal, cardiac, trachea-esophageal, renal, and limb anomalies association include one-sided renal agenesis, multicystic dysplastic kidneys, and ureter duplications.

The Role of a Bone SPECT/CT Scan in the Follow-up of a Solitary Bone Lesion in a Patient with Langerhans' Cell Histiocytosis

Langerhans' cell histiocytosis (LCH) is a rare disease observed in childhood characterized by the proliferation of Langerhans' cells resulting in focal or systemic manifestations (including the bones). Here, we present a pediatric case with a localized biopsy-proven LCH, who underwent progression from solitary to multifocal form detected on bone scintigraphy and single photon emission computerized tomography/computed tomography (SPECT/CT) performed within four months. Emphasizing on localized bone pain (predictive of osseous LCH) and local tenderness and swelling usually guides the nuclear physician to perform additional SPECT/CT with presumably an improvement of the diagnostic accuracy as demonstrated in our case.

Physiological Biodistribution of 68Ga-DOTA-TATE in Normal Subjects

Objectives: Somatostatin is an endocrine peptide hormone that regulates neurotransmission and cell proliferation by interacting with G protein-coupled somatostatin receptors (SSTRs). SSTRs are specific molecular targets of several radiotracers for neuroendocrine tumor (NET) imaging. Gallium-68 (68Ga)-DOTA-TATE is widely used for positron emission tomography/computed tomography (PET/CT) imaging of SSTRs and has shown a higher affinity for SSTR2, the most common SSTR subtype found in NETs. We aimed to analyze the distribution pattern of 68Ga-DOTA-TATE in normal subjects. Methods: A total of 617 consecutive 68Ga-DOTA-TATE PET/CT whole-body scans performed in our department from May 2015 through April 2020 with known or suspected neuroendocrine malignancies, mostly to evaluate adrenal adenomas, were retrospectively analyzed by 2 nuclear medicine physicians. One hundred eighteen subjects without a diagnosis of NET, with no tracer avid lesion of NET on 68Ga-DOTA-TATE PET/CT, and followed up for at least 6 months (average 2-3 years) without any biochemical, clinical, or imaging findings suggestive of NET were included in this study. Results: The highest uptake of 68Ga-DOTA-TATE was noted in the spleen followed by the kidneys, adrenal glands, liver, stomach, small intestine, prostate gland, pancreas head, pancreas body, thyroid gland, and uterus, in descending order. Minimal to mild uptake was detected in the submandibular glands, parotid glands, thymus, muscles, bones, breast, lungs, and mediastinum. Conclusion: Our study shows the biodistribution pattern of 68Ga-DOTA-TATE in normal subjects and the ranges of the maximum standard uptake value (SUVmax) and SUVmean values of 68Ga-DOTA-TATE obtained in several tissues for reliably identifying malignancy in 68Ga-DOTA-TATE PET/CT studies.

Central Nervous System Complications of Erdheim-Chester Disease: FDG PET/CT Findings.

ABSTRACT: Erdheim-Chester disease is an uncommon non-Langerhans cell histiocytosis. The diagnosis depends on imaging and histological criteria. The most common presentation is the multiple bone lesions with involvement of at least 1 more organ. We present the FDG PET/CT findings of a 19-year-old man who presented with central nervous system symptoms such as progressive polyuria, polydipsia, gait disturbances, and eye pain and was later diagnosed with Erdheim-Chester disease.

Does Prostate-Specific Membrane Antigen Avidity of Vertebral Hemangioma Change?

ABSTRACT: Vertebral hemangiomas are the most common benign tumors of the spine and mostly occur in the thoracic spine. Mostly they are detected incidentally during imaging studies for other reasons. We present the case of vertebral hemangioma that showed prostate-specific membrane antigen uptake in the second 68Ga-prostate-specific membrane antigen PET/CT, whereas no uptake was observed in the initial study.

Mickey Mouse Sign on Bone Scan in the Monostotic Form of Paget's Disease Mimicking Osseous Metastasis

Paget's disease is a chronic benign bone disease characterized by excessive and abnormal bone remodeling. Monostotic Paget's disease accounts for only 20% of the cases, and the monostotic form involving the vertebra with the Mickey Mouse sign is very rare. Herein, we report a case of suspected bony metastasis in the second lumbar vertebra that was diagnosed as Paget's disease because of the Mickey Mouse sign on bone scintigraphy, and the diagnosis was confirmed by biopsy. Therefore, bone scintigraphy may provide a positive contribution to the diagnosis, and may help to avoid unnecessary biopsy in cases with specific signs and patterns.

68Ga-Prostate-Specific Membrane Antigen PET-Positive Paget Bone Disease With Metastatic Prostatic Carcinoma.

Paget bone disease is a chronic benign bone disease characterized by excessive and abnormal bone remodeling. The scintigraphic and bone SPECT/CT hybrid imaging appearances of the affected bone(s) depend on the stage of the disease. We report the case of a patient newly diagnosed with prostate cancer who was found to have multiple osseous metastases, with coexisting Paget disease in the left hemipelvis diagnosed because of typical scintigraphic and SPECT/CT appearance. Ga-prostate-specific membrane antigen PET/CT was also performed for initial staging. Pagetoid bones showed increased prostate-specific membrane antigen uptake like skeletal metastases.

An Uncommon Initial Presentation of T-Cell/Histiocyte-Rich B-Cell Lymphoma: Acute Renal Failure.

T-cell/histiocyte-rich B-cell lymphoma accounts for approximately 1% to 3% of all cases of diffuse large B-cell lymphoma, and involvement of the kidneys comprises a mere 1% of the total primary extranodal lymphomas. We present a case of T-cell/histiocyte-rich B-cell lymphoma who had acute renal failure at initial presentation with bilateral lymphomatous infiltration depicted on FDG PET/CT scan. Four months after the treatment, a repeat FDG PET/CT scan revealed complete resolution of the renal lesions, indicative of the complete remission for kidneys.

Change in standardized uptake values in delayed 18F-FDG positron emission tomography images in hepatocellular carcinoma.

Delayed 18F-2-fluoro-2-deoxy-D-glucose (F-FDG) positron emission tomography (PET) imaging has been associated with improved diagnostic yield in several malignancies; however, data on the use of delayed imaging in patients with hepatocellular carcinoma (HCC) is scarce. This study aimed to examine tumoral and background standardized uptake value (SUV) alterations in dual-phase F-FDG PET/computed tomography (CT) imaging.Fifty-two HCC cases underwent dual-time-point F-FDG PET/CT examination where early and delayed images were obtained. The maximum and mean SUVs (SUVmax and SUVmean) of the tumor were determined for both time points. Similarly, the average SUVmean were also determined for background (liver, soft tissue, and spleen). Changes in tumoral and background SUV between early and delayed images were examined.The mean age was 62.0 ±â€Š12.9 years (range, 20-88 years) and the majority of the patients were men (86.5%). Tumor SUVs, both tumor SUVmean and tumor SUVmax, significantly increased at delayed images when compared to early images. In contrast, the average SUVmean for the liver, soft tissue, and spleen significantly decreased at delayed images.A significant increase in tumor SUV in delayed images in contrast to a significant decrease in background SUVs suggests that delayed images in HCC may contribute to diagnostic performance through a potential increase in the contrast between the tumor and background. However, further studies with larger sample sizes including patients with benign lesions and different grades of the disease are warranted to better elucidate the diagnostic contribution as well as the association of delayed imaging values with prognosis.

2-(fluorine-18)-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography after breast conserving surgery: Correlation with molecular markers of breast cancer.

AIM: To investigate the role of 2-(fluorine-18)-fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) early after breast-conserving surgery (BCS) in patients with breast cancer (BC) and whether we can determine which molecular biomarkers of breast carcinoma put the patients at risk. MATERIALS AND METHODS: This retrospective study involved 88 patients with histologically proven T1 or T2 BC, who were treated with BCS and underwent (18)F-FDG PET/CT study. The correlation between biological markers (estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 [HER2], and Ki-67) of the primary tumor and (18)F-FDG PET/CT findings was analyzed. RESULTS: (18)F-FDG PET/CT demonstrated the presence of BC disease (locoregional disease [LRD], distant metastases, or contralateral BC) in 26 of 88 patients (29.5%). Regarding immunohistochemical profiles, BC expressing high levels of Ki-67 were associated with an increased percentage of LRD, which was the major recurrence pattern on (18)F-FDG PET/CT. Although the BC disease was observed more commonly in patients with HER2 positivity compared to those of HER2 negative, the difference did not reach statistical significance. The patients with T2 tumor or a higher histopathological grade had a higher percentage of BC disease. CONCLUSIONS: This study demonstrated that patients with early stage BC treated with BCS have a remarkable risk of the presence of BC even early after surgery, and there was a clinically important relationship between (18)F-FDG PET/CT findings and biological markers of BC. These findings suggest that high-risk molecular biomarkers (Ki-67, HER2) can be taken into account in the decision-making the process for both preoperative imaging and planning of the surgical approach.

Carbon-14 urea breath test: does it work in patients with partial gastric resection?

OBJECTIVE: The diagnostic value of Carbon-14 urea breath test (C-14 UBT) in the detection of Helicobacter pylori (H. pylori) infection in non-operated patients has been proved. However, the efficacy of C-14 UBT in patients with partial gastric resection (PGR) has not been evaluated yet. Herein, the results of the C-14 UBT and H. pylori stool antigen test (HpSAT) in this patient group were compared with the endoscopic findings. METHODS: Multi-breath samples C-14 UBT and HpSAT were performed in all patients on the same day. Histology was used as a gold standard for testing C-14 UBT and HpSAT diagnostic efficacies. RESULTS: 30 patients (mean age: 54.6 ± 11 year) with PGR were included. The sensitivity and specificity of standard C-14 UBT were 29 and 100 %, respectively. When breath samples were collected at 20th min, and >35 CPM was selected as radioactivity threshold, the sensitivity raised to 86 % without any loss of specificity. The specificity and sensitivity of the HpSAT were 71 and 96 %, respectively. CONCLUSIONS: The sensitivity of the standard C-14 UBT was very poor for patients with PGR, and results of HpSAT were superior in this population. Certain modifications are needed if C-14 UBT is to be used in PGR patients.

Scrotal peritoneal mesothelioma on PET/CT.

Although malignant mesothelioma originating from the tunica vaginalis has been reported in the literature, direct invasion of malignant peritoneal mesothelioma to the scrotal cavity has not been described yet. Herein, we presented a diffuse malignant peritoneal mesothelioma extending inferiorly to the scrotum via inguinal canal detected on FDG PET/CT.

Marked uptake of fluorodeoxyglucose in a vocal cord after medialization: Acute and subacute positron emission tomography/computed tomography findings.

A 60-year-old male who underwent left upper lobectomy because of recently diagnosed lung cancer was admitted to the nuclear medicine department. A whole body fluorodeoxyglucose positron emission tomography/computed tomography (CT) that was performed for staging purposes, revealed an intense hypermetabolism in left vocal cord region corresponding with hyperdense mass-like material on CT scan.