PET/CT With 68Ga-PSMA and 18F-FDG in Metastatic Adenoid Cystic Carcinoma: Report of 2 Cases.

ABSTRACT: Adenoid cystic carcinoma (ACC) is a rare and slow-growing tumor, originating from salivary glands. Locoregional recurrence and distant metastasis of ACC can be visualized not only with 18F-FDG but also with 68Ga-PSMA PET/CT due to its high prostate-specific membrane antigen (PSMA) expression. We report 2 cases of metastatic ACC who underwent first 18F-FDG and then 68Ga-PSMA for staging and restaging.

Evaluation of metabolic changes in FDG PET/CT imaging after mRNA-based COVID-19 vaccination.

BACKGROUND: It isimportant to evaluate the vaccine-related metabolic changes on FDG PET/CT to avoid confusing results. We here aimed to assess the frequency and intensity of regional and systemic metabolic PET/CT changes of patients who received the mRNAbased COVID-19 vaccine (BNT162b2-Pfizer/BioNTech) and to analyze possible factors affecting these changes. METHODS: Among the patients who underwent FDG PET/CT for any indication in our department between July 2021 and December 2021, 129 volunteer patients with a history of COVID-19 vaccination were included in this prospective observational study. Bilateral axillary lymph nodes, ipsilateral deltoid muscle, bone marrow, spleen, thyroid, and liver FDG uptakes were evaluated visually and semiquantitatively for each examination. RESULTS: The frequencies of positive axillary lymph nodes after vaccination were 40%, 44.4%, 32.6%, and 44.7% in all, 1st dose, 2nd dose, and heterologous vaccination regimens groups, respectively. Maximum standardized uptake values of spleen, liver, and bone marrow were statistically high in patients with positive axillary lymph nodes than with negative ones (p < 0.05). Positive deltoid muscle uptake and diffusely increased thyroid uptake findings were observed in 10 and 8 patients, respectively. The median time interval between vaccination and imaging was 9.5 days for patients with positive axillary lymph nodes and 17 days for patients with negative nodes. In our study group, only 8 patients had a positive documented history of COVID-19 infection. DISCUSSION: Regional and systemic metabolic changes were occasionally found on FDG PET/CT imaging in patients who received the mRNA-based COVID-19 vaccine. To avoid these timely decreasing changes, we recommend managing the ideal timing of imaging or vaccination and taking a careful history.

Differentiation of insulinoma from accessory spleen by 99mTc-labelled heat-denaturated red blood cell scintigraphy: case report.

BACKGROUND: Neuroendocrine tumors (NETs) are rare tumors harboring overexpression of somatostatin receptors (SSTRs) on their cell membrane. Because some organs, such as the spleen, adrenal glands and liver, physiologically express SSTR, it might be challenging to distinguish some pancreatic NETs located in the pancreatic tail from the accessory spleen next to the splenic hilum. In this manuscript, we report a case with hypoglycemia attack and 2 different masses displayed by Gallium 68-tetraazacyclododecane tetraacetic acid-octreotate (68Ga-DOTATATE) positron emission tomography/computed tomography (PET/CT). CASE PRESENTATION: A 63-year-old woman presented to the hospital with confusion and profuse sweating. Biochemical diagnosis of insulinoma was established. 68Ga-DOTATATE PET/CT revealed two masses with increased tracer uptake located adjacent to the splenic hilum and inferior pole of the spleen which were initially reported as two separate accessory spleens. Then, 99mTc-labelled heat-denaturated red blood cell (99mTc-HDRBC) scintigraphy-single-photon emission computed tomography (SPECT)/CT was performed to distinguish a NET in the pancreatic tail from accessory spleen at the splenic hilum. Enhanced tracer uptake remained in the inferior pole of spleen, but not in the splenic hilum. The lesions were suggestive of insulinoma in the pancreatic tail and an accessory spleen adjacent to the inferior pole of the spleen. CONCLUSION: Approximately 10% of the population have an accessory spleen which can show similar imaging characteristics with pancreatic NETs, especially if located in the pancreatic tail. In our presented case, 99mTc-HDRBC scintigraphy-SPECT/CT is a useful nuclear medicine method to differentiate a NET in the pancreatic tail from accessory spleen at the splenic hilum which may avoid unnecessary surgeries in the presence of enhanced tracer uptake or vice versa.

Urinary Reflux Into the Prostate Gland and Seminal Vesicles: A Potential Pitfall in 18F-FDG and 68Ga-PSMA PET/CT.

A 64-year-old man with lung cancer underwent F-FDG PET/CT for restaging, which demonstrated intense F-FDG uptake in the right lobe of prostate gland and seminal vesicles, indicating a potential prostate cancer. In Ga-PSMA PET/CT, intense uptake in the right lobe of prostate gland and seminal vesicles was also observed but decreased in postmictional delayed images. Magnetic resonance imaging showed high signal intensity of urine in the same areas of uptakes. F-FDG and Ga-PSMA PET/CT findings in the prostate gland and seminal vesicles were considered to be a result of urinary reflux possibly because of the patient's previous transurethral resection.

Cervical versus endometrial injection for sentinel lymph node detection in endometrial cancer: a randomized clinical trial.

OBJECTIVE: To evaluate the relationship between pelvic/para-aortic sentinel lymph node status and two different injection sites of 99m-technetium (99mTc)-labeled phytate in patients with endometrial cancer. METHODS: This was a randomized controlled trial involving 81 patients with endometrial cancer. In the cervical group (n=40), injections of 99mTc were performed at the 3 and 9 o'clock positions of the uterine cervix. In the endometrial group (n=41), 99mTc was injected into the fundal endometrium using a transcervical catheter. Sentinel lymph nodes were detected through pre-operative lymphoscintigraphy and intra-operatively using a handheld gamma probe. All patients underwent complete pelvic and para-aortic lymphadenectomy procedures. Pathologic ultra-staging was performed with immunostaining for cytokeratin in sentinel lymph nodes after routine hematoxylin and eosin histological examinations. The primary endpoint was the estimation of detection rates, sensitivity, false-negative rates, negative predictive value, and analysis of the distribution of pelvic and para-aortic sentinel lymph nodes. RESULTS: The rate of detection of at least one sentinel lymph node, sensitivity, and the negative predictive value was 80%, 66.6%, 96.6% for the cervical group and 85%, 66.6%, 96.9% for the endometrial group, respectively. False-negative sentinel lymph nodes were detected in one patient from each group . There was no significant difference between the groups in terms of total sentinel lymph node count, sentinel pelvic lymph node count, and pelvic bilaterality, but the para-aortic sentinel lymph node count was significantly higher in the endometrial group (p<0.001). Ultra-staging examination of the pelvic sentinel lymph nodes revealed isolated tumor cells in one patient from each group. CONCLUSION: Transcervical endometrial tracer injection in endometrial cancer revealed similar pelvic but significantly higher para-aortic sentinel lymph node detection.

Follicular lymphoma in a patient with splenosis: a case report.

Splenosis refers to the seeding of splenic cells associated with surgery or trauma. Splenosis mimicking other diseases has been reported in the literature. To the best of our knowledge, this is the first case of follicular lymphoma in a patient with splenosis whose diagnosis of lymphoma was delayed because of a known history of splenosis. We report a 48-year-old male patient who underwent splenectomy because of injury from a high fall 20 years previously. He had no symptoms other than mild abdominal pain until 2 years previously, which was thought to be associated with splenosis. When his symptoms began to increase, he had explorative laparotomy for diagnosis, which was later confirmed as follicular lymphoma. Splenosis may delay the diagnosis of other conditions that can be underestimated. Clinicians should be aware of unusual symptoms in patients with splenosis.

Uptake of an Acrochordon Incidentally Detected on 68Ga Prostate-Specific Membrane Antigen PET/CT.

Ga prostate-specific membrane antigen (PSMA) PET/CT is a promising tool for imaging of prostate cancer. Ga-PSMA PET/CT uptake of prostate cancer and its metastases are reflective of significant overexpression of PSMA. However, PSMA expression of benign neoplasms and nonprostate epithelial malignancies is not very well defined. We report a moderate Ga-PSMA uptake of an acrochordon (skin tag), which was incidentally found in a patient referred for staging prostate cancer. Acrochordon is a frequent, small, soft, skin-colored or hyperpigmented, benign, and usually pedunculated neoplasm of the skin. Nuclear medicine physicians should be aware of it while reporting a Ga-PSMA PET/CT.

Use of Adipose-Derived Mesenchymal Stem Cells to Increase Viability of Composite Grafts.

OBJECTIVE: Chondrocutaneous composite grafts figure among the reconstruction alternatives for alar rim defects resulting from tumor resection and trauma. The major problem with composite grafts is the limited graft survival area. In the present study, the authors aimed to increase the survival area of composite grafts by utilizing the ability of stem cells to promote neovascularization which is crucial in composite graft viability. METHODS: The study included 36 adult Wistar Albino rats, which were allocated to 6 groups. Groups 1, 2, and 3 were the groups in which the grafts were implanted immediately after the defect was formed, and Groups 4, 5, and 6 were those in which grafts were adapted 4 days after the defect was formed. Composite grafts of 1 × 1 cm containing both the cartilage and the skin were prepared from 1 ear, and after forming punctures and incisions on the cartilage, the grafts were adapted to the 1 × 1 cm defects on the back. The backs of the rats in groups 1 and 4 were injected with adipose-derived stem cell (ADSC), those in groups 2 and 5 with medium solution, while the rats in Groups 3 and 6 did not receive any injection. The procedures were followed by histopathological and scintigraphic evaluations. RESULTS: An evaluation of the statistical results showed that composite graft survival areas of the group treated with stem cells increased significantly, in comparison with control and medium groups. When scintigraphic evaluations were considered, it was seen that the group treated with stem cells had significantly higher radioactive substance retention than the control group. Histopathological examination demonstrated that microscopic survival rates in the stem cell group were higher than those in the control group. Green fluorescent protein (GFP) was used in the experiment to tag adipose tissue-derived stem cells. Immunofluorescence staining studies showed less apoptosis and fewer GFP (+) stem cells in the composite grafts of the stem cell group. However, apoptosis was more severe in the control and medium groups which also had decreased vascularity in the graft. DISCUSSION: As the authors have shown in the present study, ADSCs have favorable effects on the viability of composite grafts. They have increased the survival rate of the grafts to a considerable extent. As a clinical implication of this experimental study, the authors think that in the patient of auricular and nasal defects involving the cartilage and the skin, injection of the ADSC and the adaptation of composite grafts 4 days after the preparation of the receiving bed may increase the composite graft viability rates. Thus, it has been found that if the composite grafts are implanted 4 days after stem cell injection, the injection of adipose tissue-derived mesenchymal stem cells is useful in enhancing the survival of composite grafts.

Use of Adipose-Derived Mesenchymal Stem Cells to Accelerate Neovascularization in Interpolation Flaps.

OBJECTIVE: Interpolation flaps are commonly used in plastic surgery to cover wide and deep defects. The need to, wait for 2 to 3 weeks until the division of the pedicle still, however, poses a serious challenge, not only extending treatment and hospital stay, but also increasing hospital expenses. To solve this problem, we have aimed to use the angiogenic potential of stem cells to selectively accelerate neovascularization with a view to increasing the viability of interpolation flaps and achieving early pedicle removal. MATERIALS AND METHODS: A total of 32 rats were allocated to 2 groups as control (N = 16) and experiment (N = 16). The cranial flaps 6 × 5 cm in size located on the back of the rats were raised. Then, a total suspension containing 3 × 10(6) adipose-derived mesenchymal stem cells (ADSC) tagged with a green fluorescent protein (GFP) was injected diffusely into the distal part of the flap, receiving bed, and wound edges. In the control group, only a medium solution was injected into the same sites. After covering the 3 × 5 cm region in the proximal part of the area where the flap was removed, the distal part of the flap was adapted to the uncovered distal area. The pedicles of 4 rats in each group were divided on postoperative days 5, 8, 11, and 14. The areas were photographed 7 days after the pedicles were released. The photographs were processed using Adobe Acrobat 9 Pro software (San Jose, CA) to measure the flap survival area in millimeters and to compare groups. Seven days after the flap pedicle was divided, the rats were injected with 250 mCi Tc-99 mm (methoxy-isobutyl-isonitrie) from the penile vein, and scintigraphic images were obtained. The images obtained from each group were subjected to a numerical evaluation, which was then used in the comparison between groups. The flaps were then examined by histology to numerically compare the number of newly formed vessels. Neovascularization was also assessed by microangiography. In addition, radiographic images were obtained by mammography and evaluated quantitatively. RESULTS: An evaluation of statistical results revealed a significant increase in the flap survival area of the group on stem cell treatment in comparison to the control group. In scintigraphic examinations, the rate of radioactive substance retention was significantly higher in the stem cell group, relative to the control group. Histopathologic examination showed that the capillary density in the stem cell group was higher than that in the control group. Green fluorescent protein had been used to label ADSC in the experiment and it was found by immunofluorescence staining that endothelial samples of control animals did not have GFP (+) cells, whereas all the animals in the experiment group had GFP (+) cells. The comparison of microangiographic images of the experiment and control groups demonstrated significantly elevated vascularity in the former, relative to the latter. DISCUSSION: It has been established in the current study that ADSC injection worked well in speeding up the neovascularization of interpolated flaps and reducing the time of pedicle division. It seems possible to minimize the morbidity of interpolated skin flaps with mesenchymal stem cell therapy at an appropriate dose and for an appropriate length of time.

Pulmonary 18F-FDG microembolism detected on only delayed image in a PET/CT study.

Focal 18F-FDG pulmonary uptake on PET without corresponding abnormality on CT is an incidental and rare finding. This artifact is associated with iatrogenic FDG microembolus as a result of vascular endothelium damage during injection. We present a pulmonary FDG microembolus in a patient evaluated for suspicion of gallbladder cancer not in early (standard 1-hour imaging after FDG injection) but in delayed image. To our knowledge, this is the first case that describes the possibility of FDG microembolism on only delayed image in a PET/CT study.

Correlation of Cystatin-C and radionuclidic measurement method of glomerular filtration rate in patients with lung cancer receiving cisplatin treatment.

OBJECTIVE: Cisplatin is a chemotherapeutic agent which affects renal functions adversely. The best indicator of renal functions is glomerular filtration rate (GFR) measurement. Cystatin-C appears to be a good alternative to existing methods of measuring GFR. However, it is controversial whether Cystatin-C demonstrates GFR correctly for patients receiving chemotherapy. This study aimed to investigate the correlation between GFR values calculated by Cystatin-C based formulas, radionuclidic method (multiple blood sampling) and blood Cystatin-C values in patients with lung cancer, receiving cisplatin treatment in both pre-treatment and post-treatment periods. MATERIALS AND METHODS: Thirty-six patients with lung cancer who were going to receive cisplatin treatment were included in this study. However, the evaluation was performed with 20 patients since 16 of them could not complete the treatment. Blood Cystatin-C values, GFR values calculated via Cystatin-C based formulas, and radionuclidic method were investigated before and after the cisplatin treatment. RESULTS: After treatment significant decreases were detected in GFR values, obtained via radionuclidic measuring method. However, there was no significant difference in Cystatin-C values between pre-treatment and post-treatment periods. Also GFR values obtained by Cystatin-C based formulas were not significantly different in pre-treatment and post-treatment periods. There were meaningful correlations between radionuclidic method and Cystatin-C values and Cystatin-C based formulas before treatment. However, all correlations disappeared after the treatment. CONCLUSION: GFR values, calculated by Cystatin-C may not be reliable in following renal functions in patients receiving chemotherapy. When reliable monitoring of the renal functions is necessary radionuclidic method may be preferred in these patients.

Low radioiodine uptake in congestive heart failure.

OBJECTIVES: Our aim was to compare the radioiodine uptake (RAIU) of congestive heart failure (CHF) patients with that of a control group and investigate the prognostic value. We also assessed correlations of RAIU with other clinical parameters. METHODS: A total of 32 CHF patients and 14 controls were included in this study. RAIU was measured at the fourth and 24th hour using an uptake probe. The patients were followed up for a mean period of 32.09±8 months. RESULTS: The mean fourth-hour RAIU was 6.28±5.51 and the mean 24th-hour RAIU was 14.43±9.49 in the patient group. The mean fourth and 24th hour RAIUs of the control group were 9.93±1.92 and 22.90±5.89, respectively, which were statistically higher than that of the patient group (P=0.0001 and 0.001, respectively).Cardiac death occurred in nine patients during follow-up. The fourth and 24th hour uptake ratios were statistically significantly lower in the cardiac death group compared with the no-death group (3±2.01 vs. 7.57±5.93 and 7.39±7.34 vs. 17.18±8.9, respectively; P=0.003 and 0.007). On stepwise multivariate Cox regression analyses, only urea proved to be a significant independent predictor of cardiac death (hazard ratio 1.021; 95% confidence interval 1.005-1.037; P<0.008). Significant negative correlations were found between the fourth and 24th hour RAIUs and high-sensitivity C-reactive protein, urea, and creatinine levels, but no correlation was found between RAIUs and estimated glomerular filtration rate. CONCLUSION: CHF patients have lower RAIU values probably because of an expanded iodine pool and prolonged Wolff-Chaikoff effect. Also, patients who died during follow-up had lower RAIU values, but RAIU did not emerge as an independent predictor of death. However, studies with larger patient groups are definitely needed.

Radioiodine therapy in Graves' disease: is it possible to predict outcome before therapy?

OBJECTIVE: To assess the predictability of outcome and evaluate the factors that may lead to treatment failure in patients with Graves' disease who are treated with a single dose of radioiodine. MATERIALS AND METHODS: This is a retrospective study of 123 patients (M: 42; F: 81) with Graves' disease who received radioiodine therapy with a single fixed (10 mCi) dose for hyperthyroidism. Pretreatment age, sex, BMI, type of anti-thyroid drug used, propylthiouracil doses, iodine uptake, uptake ratio (4/24 h radioiodine uptake), and thyroid volume of the patients in whom radioiodine therapy succeeded or failed were compared. RESULTS: Post-therapy follow-up revealed that therapy failed in 22% of the patients. Iodine uptakes and uptake ratios and volumes were found to be significantly higher in patients in whom therapy failed. It was observed that uptake ratio was at least 1 in 25 patients (20%), and therapy failed in 20 (80%) of these patients. Of the 98 patients (80%) in whom uptake ratio was less than 1, therapy was unsuccessful in only seven (7%). CONCLUSION: Uptake ratio is a simple index that may be used to predict the patients in whom therapy may fail or succeed. In patients with Graves' disease who have an uptake ratio of less than 1, radioiodine appears to be an effective dose with high success rates. In contrast, because of the high rates of failure in patients with an uptake ratio of at least 1, use of radioiodine therapy at a dose of 10 mCi does not seem to be appropriate.

Reduced heart rate response to dipyridamole in patients undergoing myocardial perfusion SPECT.

OBJECTIVE: A mild decrease in blood pressure and increase in heart rate (HR) are considered normal hemodynamic responses to dipyridamole. In this study, we tried to investigate HR response to dipyridamole and its predictors in patients undergoing gated myocardial perfusion single photon emission computed tomography (SPECT). METHODS: 201 consecutive patients undergoing dipyridamole stress Tc99m-MIBI or Tl-201 gated myocardial perfusion SPECT were prospectively enrolled. Dipyridamole was infused over 4 min and radiopharmaceutical was injected 3 min after the end of infusion. A reduced heart rate response to dipyridamole considered if the HR ratio (peak HR/rest HR) was 1.20 or less. Stress (sLVEF), rest (rLVEF) left ventricular ejection fractions, stress and rest motion (SMS, RMS) and thickening scores (STS, RTS) were derived automatically by QGS. Summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for myocardial perfusion were calculated. Patients were grouped according to HR response and groups were compared. A logistic regression analysis was used to determine independent predictors of reduced HR response. RESULTS: Reduced HR response was found in 78 % of patients. Patients with abnormal HR response were more frequently had a history of diabetes mellitus, chronic renal failure, and had lower high-density lipoprotein (HDL) levels. Peak HR, SSS, SRS, sLVEF and rLVEF were lower; rest HR, RTS, and the number of patients with ≤ 45 % sLVEF and rLVEF were higher in reduced HR response group (all p < 0.05). There was no difference between groups by means of gender, rest and peak systolic or diastolic tension, SDS, SMS, STS, RMS, history of hypertension, peripheral arterial disease, metabolic syndrome, coronary interventions, digoxin, calcium channel blocker or beta blocker usage. Multivariable logistic regression analysis demonstrated that the independent predictors of reduced HR response were HDL, rest HR and SSS. When HDL was removed from the model, chronic renal failure also emerged as an independent predictor. CONCLUSION: Reduced HR response to dipyridamole is associated with ventricular dysfunction, cardiac autonomic neuropathy. Low HDL levels also seem to be related with reduced HR response.

Sentinel lymph node biopsy with a gamma probe in patients with high-risk cutaneous squamous cell carcinoma: follow-up results of sentinel lymph node-negative patients.

OBJECTIVE: Lymphoscintigraphy (LS) and sentinel lymph node biopsy have become the standard of care for melanoma and breast cancer. However, the data on patients with cutaneous squamous cell carcinoma (SCC) are limited. We aimed to evaluate and identify the role of LS and sentinel lymph node biopsy in patients with high-risk cutaneous SCC. METHODS: Nineteen patients (13 men, six women; 47-87 years of age, mean age 67.5 ± 12.3) with SCC were included in the study. LS was performed on all patients after intracutaneous injection of Tc-99m nanocolloid. Primary lesions and sentinel lymph nodes (SLNs) were excised with the help of a gamma probe. RESULTS: A total of 26 SLNs and 32 secondary lymph nodes were imaged on LS and were marked. During surgery, 29 SLNs, 21 secondary lymph nodes and three nonactive lymph nodes were excised. In total, 53 lymph nodes were removed surgically. A histopathological study revealed that all lymph nodes were negative for metastasis. Patients were followed up for an average of 41.1 ± 22.2 months (7-80 months). Until the time of data collection, 14 patients were alive and had no regional lymph node or distant metastasis. Local recurrence was seen in only one patient. He was reoperated upon 38 months ago. CONCLUSION: The feasibility of determining SLNs using LS and an intraoperative gamma probe in patients with cutaneous SCC was shown. Unnecessary elective lymph node dissection and possible complications could be avoided in 19 patients.

Obesity control and low protein diet preserve or even improve renal functions in Bardet-Biedl syndrome: a report of two cases.

BACKGROUND: Bardet-Biedl syndrome (BBS) is a rare autosomal-recessive disorder characterized by abdominal obesity, mental retardation, dysmorphic extremities, retinal dystrophy, hypogonadism, and kidney structural abnormalities or functional impairment. It is now considered a significant cause of chronic and end-stage renal disease in children. To the best of our knowledge there have been no previous studies on the role of diet in the management of renal functions in patients with BBS. CASE REPORTS: Two siblings, aged 32 and 27 years, with BBS are presented. On admission both patients were obese, with body mass indexes (BMI) of 40 and 39 kg/m2. Their creatinine clearances (CrCl) were 41 and 24 mL/min. After 2 years of follow-up with a diet consisting of 0.6 g/kg/day protein and 1400 kcal/day energy, their BMI's were decreased to 29 and 27 kg/m2, whereas their CrCl's were increased to 44 and 32 mL/min, respectively. 99mTc-MAG3 scintigraphy also revealed improved renal function. CONCLUSIONS: Since this syndrome most likely results in end-stage renal disease, follow-up of renal dysfunction is essential. Low protein diet and/or obesity control may slow the progression of renal failure in patients with BBS.