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Clinical Nuclear Medicine - Current Issue

Clinical Nuclear Medicine - Current Issue
  1. 18F-NaF PET-CT in Symptomatic Fabella Syndrome
    imageAbstract: Fabella is a sesamoid bone, located within the tendon of the lateral head of the gastrocnemius muscle. It may be associated with posterolateral knee pain because of repetitive friction over the posterolateral femoral condyle. We report a case of a 64-year-old woman presenting with right posterolateral knee pain. 18F-NaF PET-CT demonstrated increased uptake posterior to the right knee joint localizing to a fabella. Standard examination and radiographic imaging excluded other causes for posterolateral knee pain, and the increased activity was considered to be secondary to fabella syndrome. NaF PET-CT can provide useful information in the evaluation of posterolateral knee pain.

  2. Massive Idiopathic Oropharyngeal and Laryngeal Granulomatosis on FDG PET/CT
    imageAbstract: Idiopathic granulomatosis is a rare entity and has varied manifestations and imaging findings. A 44-year-old woman with sore throat and worsening dyspnea had multiple oropharyngeal and supraglottic masses on laryngoscopic examination. FDG PET/CT demonstrated diffuse tumor-like mucosal/submucosal lesions with intense uptake involving the oropharynx, supraglottis, and hypopharynx. Surgical biopsy showed chronically inflamed granulation tissue without malignancy, necrosis, or vasculitis. All stains were negative for any organisms. The image highlights the necessity of including granulomatosis as a differential from malignancy in interpretation of FDG PET/CT showing diffuse mucosal/submucosal oropharyngeal and/or laryngeal lesions but without established diagnosis.

  3. FDOPA PET-CT of Nonenhancing Brain Tumors
    imageBackground: Primary brain tumor grading is crucial to rapidly determine the therapeutic impact and prognosis of a brain tumor as well as the tumors’ aggressiveness profile. On magnetic resonance imaging, high-grade tumors are usually responsible for blood -brain barrier breakdowns, which result in tumor enhancement. However, this is not always the case. The main objective of this study was to evaluate the diagnostic value of FDOPA PET in the assessment of primary brain tumor aggressiveness with no contrast enhancement on MRI. Methods: Fifty-three patients were prospectively included: 35 low-grade and 18 high-grade histologically proven gliomas, with no contrast enhancement. Each patient underwent static PET acquisitions at 30 minutes. All patients had MRSI with measurements of different metabolites ratio. Results: FDOPA was useful in the subgroup of low-grade gliomas, discriminating between dysembryoplastic neuroepithelial tumor and grade II oligodendroglioma (P < 0.01). An optimal threshold of the maximum standardized uptake value at 30 minutes (SUVmax (T/N)30) = 2.16 to discriminated low- from high-grade gliomas with a sensitivity of 60%, specificity of 100%, PPV of 100%, and NPV of 83.33% (P < 0.01). The nCho/Cr and nCho/NAA ratios were significantly higher in high- than in low-grade gliomas (P < 0.03 and P < 0.04, respectively). A significant positive correlation between MRSI ratios and SUVmax was found. Conclusion: Including data from amino acid metabolism used alone or in association with MRSI allows us to discriminate between dysembryoplastic neuroepithelial tumor and grade II oligodendroglioma and between low- and high-grade gliomas with no contrast enhancement on MRI.

  4. Spontaneous Intracranial Hypotension With Site of Leak Detected Only After 111In-DTPA Cisternogram
    imageAbstract: A 54-year-old man with a 3-week history of orthostatic headache and acute on chronic subdural hematoma presented with imaging findings suggestive of spontaneous intracranial hypotension. Three myelograms were negative for leak, and nontargeted epidural blood patches did not result in symptom relief. A cerebrospinal fluid leak study using 111In-DTPA with SPECT/CT demonstrated a focal area of asymmetric activity at the left C2 nerve root. A left C2 root tie-off, targeted epidural blood patch, and Dura seal glue resulted in resolution of patient symptomatology highlighting the importance of fused SPECT/CT images in detection of an occult cerebral spinal fluid leak.

  5. Detection and Viability of Colorectal Liver Metastases After Neoadjuvant Chemotherapy: A Multiparametric PET/CT-MRI Study
    imagePurpose: The aim of this study was to compare combined gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA)–enhanced and diffusion-weighted (DW) MRI with IV contrast-enhanced 18F-FDG PET/CT to detect and assess the viability of colorectal liver metastases (CLMs) after neoadjuvant chemotherapy (NAC). Patients and Methods: After NAC, 45 patients with CLMs were prospectively enrolled and underwent combined Gd-EOB-DTPA–enhanced and DW-MRI and contrast-enhanced 18F-FDG PET/CT. Forty patients subsequently underwent surgery based on intraoperative ultrasound, which served as the reference standard for the presence of CLMs. The number of metastases detected by each technique was then compared. In 69 resected metastases, the SUVmean and SUVmax, mean and maximum target-to-background ratio (TBR), total lesion glycolysis, metabolic tumor volume, and mean and minimum apparent diffusion coefficient (ADC) were examined to identify correlations with the corresponding tumor viability (TV) determined from histological specimens. Results: Intraoperative ultrasound revealed 153 CLMs, 122 of which were resected. The detection rate of MRI and contrast-enhanced 18F-FDG PET/CT were similar (P = 0.61). The SUVmax and minimum ADC were negatively correlated (r = −0.34, P = 0.005) on preoperative imaging after NAC. However, TV was significantly correlated with the maximum TBR (r = 0.33, P = 0.006) and mean TBR (r = 0.37, P = 0.002), but not with the minimum ADC (r = −0.02, P = 0.9) or mean ADC (r = 0.01, P = 0.9). Conclusions: Combined Gd-EOB-DTPA–enhanced and DW-MRI and contrast-enhanced 18F-FDG PET/CT allow confident detection of CLMs, but only 18F-FDG PET metrics are associated with TV after NAC.

  6. Predictive Value of 18F-FDG PET/CT for Vascular Invasion in Patients With Hepatocellular Carcinoma Before Liver Transplantation
    imageBackground: Positron emission tomography-computed tomography using 18F-fluorodeoxyglucose (18F-FDG PET/CT) has been widely used in oncology. Vascular invasion of hepatocellular carcinoma (HCC) is associated with a high risk of tumor recurrence and low survival rates after liver transplantation (LT). This retrospective study determined the predictive value of 18F-FDG PET/CT for vascular invasion in patients with HCC before LT. Methods: Sixty-five patients with HCC who underwent 18F-FDG PET/CT before LT were retrospectively included between January 2010 and July 2012. Volumes of interest (VOIs) were drawn for the tumors and normal liver tissues, and the standardized uptake value (SUV) in each VOI was measured. The maximal SUV (SUVmax) of the tumor, the ratio of tumor SUVmax to normal liver SUVmax (TSUVmax/LSUVmax), and the ratio of tumor SUVmax to normal liver SUVmean (TSUVmax/LSUVmean) were measured. The predictive value of metabolic parameters and conventional prognostic factors were analyzed. Results: Vascular invasion was pathologically confirmed in 15 (23.08%) of 65 patients. Compared with patients without vascular invasion, patients with vascular invasion exhibited significantly higher serum alpha-fetoprotein (AFP) (P < 0.001), larger tumor size (P = 0.001), higher tumor number (P = 0.017), and higher SUVmax, TSUVmax/LSUVmax ratio, and higher TSUVmax/LSUVmean ratio (P = 0.008, P = 0.002, and P = 0.006, respectively). Univariate analysis revealed that SUVmax, TSUVmax/LSUVmax ratio, and TSUVmax/LSUVmean ratio of FDG PET/CT were significantly associated with vascular invasion in patients with HCC before LT (P = 0.019, P = 0.018, and P = 0.015, respectively). Multivariate analysis revealed that the TSUVmax/LSUVmean ratio of 18F-FDG PET/CT was a significant predictor of vascular invasion (P = 0.04) and that the TSUVmax/LSUVmax ratio of 18F-FDG PET/CT was an independent predictor of vascular invasion, although this finding demonstrated borderline statistical significance (P = 0.06) in patients with HCC before LT. Conclusions: According to the study results, the TSUVmax/LSUVmean ratio is an independent and significant predictor of vascular invasion, and the TSUVmax/LSUVmax ratio of 18F-FDG PET/CT is an independent predictor of vascular invasion, which is the main negative outcome after LT. Therefore, FDG PET/CT can provide vital information for determining prognosis and selecting an optimal candidate of LT for HCC.

  7. FDG PET/CT Assesses the Risk of Femoral Pathological Fractures in Patients With Metastatic Breast Cancer
    imagePurpose: Assessment of pathological fracture risk is critical to optimize the use of prophylactic orthopedic fixation to prevent pathological fractures. Better prediction of pathological fracture risk is needed. We evaluated if quantitative measures of FDG avidity can assess femoral pathological fracture risk in patients with metastatic breast cancer (MBC). Patients and Methods: A Health Insurance Portability and Accountability Act–compliant retrospective case-control study was performed under institutional review board waiver. Patients with MBC who received an FDG PET/CT from January 2008 to December 2014 and had pathological fracture of the proximal femur within 3 months of PET/CT were selected as cases. Patients with MBC who had an FDG PET/CT in 2013 were sequentially screened in reverse chronological order to identify patients with proximal femoral metastases on PET/CT but no subsequent pathological fracture to serve as a control group. The prespecified goal was to have twice the number of controls as cases. Target lesions in the proximal femur, from femoral head to 5 cm below the lesser trochanter, were analyzed on FDG PET/CT for SUVmax, SUVmean, metabolic tumor volume, and total lesion glycolysis. Wilcoxon rank sum test was used to compare continuous variables in cases and controls. A nonparametric receiver operating characteristic analysis was performed to assess the ability of quantitative FDG measurements to differentiate between cases and controls. Results: In 27 cases with pathological fracture and 55 controls without pathological fracture, all 4 quantitative measures of FDG avidity were statistically different between cases and controls (P < 0.001). A total lesion glycolysis of 81 could differentiate between fracture and nonfracture patients with accuracy, sensitivity, and specificity of 0.83, 0.85, and 0.80, respectively. Conclusions: Quantitative measures of FDG avidity may help identify breast cancer patients at high risk of subsequent pathological fracture of the proximal femur.

  8. Intrathoracic Accessory Lobe of Liver Masquerading as a Paraesophageal Mass
    imageAbstract: Heterotopic liver tissue is a relatively rare finding, which has historically been discovered incidentally during surgery or at autopsy. However, we present a 28-year-old woman who presented to the emergency department with shortness of breath and stabbing chest pain. An emergent CT angiogram of the chest was performed, which incidentally revealed a mediastinal paraesophageal mass. Subsequent endoscopic ultrasound showed a hypoechoic area that appeared to connect to the liver. A liver/spleen scan with SPECT/CT with 99mTc sulfur colloid demonstrated that the mass was paraesophageal heterotopic liver tissue with a connection to the orthotropic liver by a small stalk.

  9. Estimated Internal and External Radiation Exposure of Caregivers of Patients With Pediatric Neuroblastoma Undergoing 131I Metaiodobenzylguanidine Therapy: A Prospective Pilot Study
    imagePurpose: Current recommendations suggest that family members should participate in the care of children receiving in-hospital 131I metaiodobenzylguanidine (MIBG) therapy for neuroblastoma. The present study aimed to measure the external radiation exposure and estimate the internal radiation exposure of caregivers during the hospital stay for 131I MIBG therapy. Materials and Methods: Caregivers received radiation safety instructions and a potassium iodide solution for thyroid blockade before patient admission. External radiation exposure was determined using a personal pocket dosimeter. Serial 24-hour urine samples were collected from caregivers during the hospital stay. Estimated internal radiation exposure was calculated based on the urine activity. Results: Twelve cases (mean age, 6.2 ± 3.5 years; range, 2–13 years) were enrolled. The mean administered activity was 233.3 ± 74.9 (range, 150.0–350.0) mCi. The mean external radiation dose was 5.8 ± 7.2 (range, 0.8–19.9) mSv. Caregivers of children older than 4 years had significantly less external radiation exposure than those of children younger than 4 years (1.9 ± 1.0 vs 16.4 ± 5.0 mSv; P = 0.012). The mean estimated internal radiation dose was 11.3 ± 10.2 (range, 1.0–29.8) μSv. Conclusions: Caregivers receive both external and internal radiation exposure while providing in-hospital care to children receiving 131I MIBG therapy for neuroblastoma. However, the internal radiation exposure was negligible compared with the external radiation exposure.

  10. Bone Scan, PET-CT, and MRI in Disseminated Coccidioidomycosis
    imageAbstract: Coccidioidomycosis (valley fever) is a systemic fungal infection resulting from inhalation of the Coccidioides immitis or posadasii spores. In many cases, infection causes a self-limited community-acquired pneumonia; however, in patients with risk factors, such as immunosuppression or African or Pacific Island ancestry, significant morbidity and mortality from disseminated disease may occur. Presented here are comparative images using 99mTc-MDP bone scan, 18F-FDG PET/CT, and MRI. Each demonstrates particular strengths, which aid in assessing the extent of systemic involvement of a biopsy-proven case of disseminated coccidioidomycosis.

  11. Desirable Properties of Radiopharmaceuticals for Sentinel Node Mapping in Patients With Breast Cancer Given the Paradigm Shift in Patient Management
    imageAbstract: Over the past 2 decades, lymphoscintigraphy and sentinel node biopsy have become widely accepted and are used by surgeons to stage many solid cancers, especially breast cancer. However, despite growing experience, there are a number of unresolved issues. In addition, the impact of a new radiopharmaceutical remains to be determined. The present article addresses some of these issues (either unresolved, recurrent, or newly emerged), with a focus on the properties of radiopharmaceuticals used for sentinel node mapping in breast cancer.

  12. Radio-Guided Lymph Node Mapping in Bladder Cancer Using SPECT/CT and Intraoperative γ-Probe Methods: Reply
    No abstract available

  13. Quality and Safety in Health Care, Part XXI: PSOs and the Vascular Quality Initiative
    Abstract: Congress provided for the formation of patient safety organizations (PSOs) so that physicians and other providers would come forward to improve the safety and quality of health care. Important legal safeguards for the providers and patients were put in place for PSOs. The Society for Vascular Surgery (SVS) PSO operates the Vascular Quality Initiative. The latter gathers information from certain commonly done vascular procedures. First, information is collected so a risk adjustment determination of each individual patient can be done. Then the details of every procedure are recorded for later analysis of the processes of the patient's care. In addition, outcome analysis from all procedures is carried out. This registry is an important source of data for research improving health care safety and quality.

  14. 18F-FDG PET/CT Imaging in Adrenal Cryptococcosis
    imageAbstract: Cryptococcosis is a fungal infection, relatively rare in the absence of impaired immunity. Lung or brain may be involved. Cryptococcal dissemination is rare in absence of impaired immunity, and documentation of alone adrenal involvement without central nervous system involvement is rare. Here, we present a case of an immunocompetent patient presented with bilateral adrenal cryptococcosis with adrenal insufficiency, without central nervous system involvement and 18F-FDG PET/CT correctly identified the residual disease.

  15. An 111In-Pentetreotide Positive Sclerosing Pneumocytoma
    imageAbstract: A 43-year-old woman had an incidental lung mass identified on shoulder x-ray performed for pain. Contrast-enhanced CT showed a 38-mm mass in the medial segment of the right middle lobe, with features suggestive of carcinoid tumor. A 111In-pentetreotide scan showed intense uptake; furthermore, fine needle aspiration biopsy yielded neuroendocrine cells confirming the carcinoid hypothesis. However, definitive surgical histology showed a sclerosing pneumocytoma. This could potentially suggest that such rare tumors, with metastatic potential, could respond to somatostatin analogue treatment.

  16. Parathyroid Adenoma Mimicking a Malignant Lymph Node on 18F-Choline PET-CT
    imageAbstract: Prostate carcinoma is the most common cancer in men. After local therapy, disease recurs in many patients. A choline PET/CT is indicated in case of biochemical relapse of prostate carcinoma to determine the site of recurrence (local and/or distant) and to help select the next line of therapy. Choline PET-CT is also known to show an elevated uptake in hyperfunctioning parathyroid adenoma. This case report shows the difficulty to distinguish between both entities if they occur simultaneously in an oncologic patient.

  17. Cerebral Parenchymal Photopenia on FDG-PET/CT Reflecting Vasogenic Edema Due to Leptomeningeal Metastasis in Breast Cancer
    imageAbstract: A 61-year-old woman with metastatic breast cancer presented with migrainelike episodes over the past 10 months. FDG-PET/CT(PET/CT) showed relatively symmetric areas of photopenia predominantly in the bilateral superior parietal lobules. Subsequent contrast-enhanced MRI revealed leptomeningeal metastasis in the bilateral posterior parietal regions with associated vasogenic edema in the adjacent brain parenchyma. There was no clear evidence of parenchymal metastasis on MRI. After chemotherapy, the areas of abnormality resolved on PET/CT 8 months later, and the patient showed interval symptomatic improvement. The present case demonstrates brain parenchymal photopenia on PET/CT as an indirect sign of leptomeningeal metastasis reflecting regional vasogenic edema.

  18. Pulmonary Opacities and Bronchiectasis Avid on 68Ga-PSMA PET
    imageAbstract: Prostate-specific membrane antigen (PSMA) is highly expressed in prostate cancer, and the expression increases with tumor aggressiveness, metastatic disease, and recurrence. Despite its name, PSMA is also expressed in neovasculature of other tumors including lung cancer. Here, we demonstrate a case of increased PSMA expression on 68Ga-PSMA PET/CT in benign lung opacities and bronchiectasis in a prostate cancer patient. Thus, increased PSMA activity in the lungs may be due to both benign and malignant diseases and warrants further evaluation.

  19. Incidental 99mTc-DTPA Uptake in Tarlov Cysts on Radionuclide SPECT/CT Cisternography
    imageAbstract: Sacral perineural cysts are also known as Tarlov cysts. A 58-year-old man with suspected intracranial hypotension was evaluated with 99mTc-DTPA radionuclide cisternography. Radionuclide planar and SPECT/CT cisternography revealed 99mTc-DTPA uptake in sacral lesions. Spine MRI confirmed Tarlov cysts at the S1 and S2 levels.

  20. Interrupted 131I Procedures for Patients With Differentiated Thyroid Cancer: Comparing Thyroxine Withdrawal With Recombinant Thyrotropin Preparation Techniques
    imageObjective: In patients with differentiated thyroid carcinoma scheduled to receive doses of 131I for diagnostic or therapeutic purposes, we compared patients prepared with thyroid hormone withdrawal (THW) versus recombinant human thyroid stimulating hormone (rh-TSH) to evaluate the incidence of cancelled procedures because of inadequate thyroid stimulation. Methods: Thyroid cancer patients after thyroidectomy who were scheduled for diagnostic or therapeutic 131I procedures between January 2012 and June 2015 were retrospectively reviewed. Patients were divided based on preparation modality (THW vs rh-TSH), and the incidence of cancelled procedures was compared. Results: Charts from 761 patients were reviewed, 292 THW and 569 rh-TSH. A total of 10 patients (3.4%) in the THW group had cancelled procedures because of insufficient thyroid stimulation (TSH < 20 mU/L). If a TSH threshold of 30 mU/L were used, 57 patients (17.1%) would have been cancelled. Comparing the groups with chi-squared analysis for both TSH thresholds yielded significantly more cancellations in the THW group (P < 0.001). Conclusions: Our study has shown that THW in preparation for 131I procedures leads to significantly more cancellations because of insufficient thyroid stimulation as compared with rh-TSH, which led to no cancellations. The added cost and inconvenience to this cancer population should therefore be considered when selecting a preparation modality. Level of Evidence: Retrospective cohort—Level III

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