Biochemically recurrent prostate cancer: rationalisation of the approach to imaging.

AIM: To assess the utility of magnetic resonance imaging (MRI) in addition to the additive benefit of the conventional imaging techniques, computed tomography (CT) and nuclear medicine (NM) bone scintigraphy, for investigation of biochemical recurrence (BCR) post-prostatectomy where access to prostate specific membrane antigen (PSMA) positron-emission tomography (PET)-CT is challenging. MATERIALS AND METHODS: Relevant imaging over a 5-year period was reviewed. Ethical approval was granted by the internal review board. All patients with suspected BCR, defined as a PSA ≥0.2 ng/ml on two separate occasions, underwent a retrospective imaging review. This was performed on PACS archive search database in a single centre using search terms "PSA" and "prostatectomy" in the three imaging methods; MRI, CT, and NM bone scintigraphy. All PSMA PET CT performed were recorded. RESULTS: One hundred and eighty-five patients were identified. Patients with an MRI pelvis that demonstrated distant metastases (i.e., pelvic bone metastases or lymph node involvement more cranial to the bifurcation of the common iliac arteries) were more likely to have a positive CT and/or NM bone scintigraphy. The Pearson correlation coefficient between the findings of M1 disease at MRI pelvis and the presence of distant metastases at CT thorax, abdomen, pelvis and NM bone scintigraphy was calculated at 0.81 (p<0.01) and 0.91 (p<0.01) respectively. CONCLUSION: An imaging strategy based on risk stratification and technique-specific selection criteria leads to more appropriate use of resources, and in turn, increases the yield of conventional imaging methods. MRI prostate findings can be used to predict the additive value of CT/NM bone scintigraphy allowing a more streamlined approach to their use.

Value of antigranulocyte scintigraphy with Tc-99m-sulesomab in diagnosing combat-related infections of the musculoskeletal system.

AIM: Combat-related extremity injuries are regularly associated with long-term complications such as chronic infection, especially osteomyelitis. Clinical examination and laboratory parameters do not usually allow reliable diagnosis. In contrast, imaging techniques enable constructive assertions to be made about the location and extent of an infection of the peripheral musculoskeletal system. The aim of this study was therefore to determine the diagnostic reliability of three-phase bone scanning and antigranulocyte scintigraphy using Tc-99m-sulesomab (Leukoscan) in the diagnostic clarification of infections associated with combat-related extremity injuries. METHODS: Twenty-seven male patients (mean age 33.9 years) with suspected combat-associated infections of the extremities were included in this retrospective analysis. All patients underwent three-phase bone scanning using Tc-99m-HDP followed by antigranulocyte scintigraphy with Tc-99m-sulesomab. In 26 of the 27 patients, a CT scan of affected limb was obtained, where the secondary fusion with single photon emission CT data set was possible. The diagnostic reliability of imaging techniques was validated against microbiological samples obtained during surgery and used as gold standard. RESULTS: Three-phase bone scanning yielded a positive result in all patients, with 18 scans classified as true positive (TP) and nine scans as false positive (FP). This produced a sensitivity of 100%, a specificity of 0% and a positive predictive value (PPV) of 67%. Antigranulocyte scintigraphy recognised 13 patients as TP, 1 patient as FP, 8 patients as true negative (TN) and 5 patients as false negative (FN), which gave a sensitivity of 72%, a specificity of 88%, a PPV of 93%, a negative predictive value (NPV) of 62% and an accuracy of 78%. CT recognised in 7 cases a TP result, in 3 cases an FP, in 5 cases a TN and in 11 cases an FN result. This produced a sensitivity of 39%, a specificity of 63%, a PPV of 70%, an NPV of 31% and an accuracy of 46%. CONCLUSIONS: Three-phase bone scanning did not deliver any diagnostic benefit, since no result was able to differentiate unequivocally between infection-related and reactive changes. Antigranulocyte scintigraphy using Tc-99m-sulesomab represented a highly suitable technique for diagnostically clarifying combat-related infections of the extremities. It is superior to CT in sensitivity, specificity, PPV, NPV and accuracy.

Diagnostic Imaging: Appropriate and Safe Use.

The use of diagnostic radiography has doubled in the past two decades. Image Gently (children) and Image Wisely (adults) are multidisciplinary initiatives that seek to reduce radiation exposure by eliminating unnecessary procedures and offering best practices. Patients with an estimated glomerular filtration rate less than 30 mL per minute per 1.73 m2 may have increased risk of nephropathy when exposed to iodinated contrast media and increased risk of nephrogenic systemic fibrosis when exposed to gadolinium-based contrast agents. American College of Radiology Appropriateness Criteria can help guide specific diagnostic imaging choices. Noncontrast head computed tomography is the first-line modality when a stroke is suspected. Magnetic resonance imaging stroke protocols and computed tomography perfusion scans can augment evaluation and potentially expand pharmacologic and endovascular therapy timeframes. Imaging should be avoided in patients with uncomplicated headache syndromes unless the history or physical examination reveals red flag features. Cardiac computed tomography angiography, stress echocardiography, and myocardial perfusion scintigraphy (nuclear stress test) are appropriate for patients with chest pain and low to intermediate cardiovascular risk and have comparable sensitivity and specificity. Computed tomography pulmonary angiography is the preferred test for high-risk patients or those with a positive d-dimer test result, and ventilation-perfusion scintigraphy is reserved for patients with an estimated glomerular filtration rate less than 30 mL per minute per 1.73 m2 or a known contrast allergy. Computed tomography with intravenous contrast is preferred for evaluating adults with suspected appendicitis; however, ultrasonography should precede computed tomography in children, and definitive treatment should be initiated if positive. Ultrasonography is the first-line modality for assessing right upper quadrant pain suggestive of biliary disease. Mass size and patient age dictate surveillance recommendations for adnexal masses. Imaging should not be performed for acute (less than six weeks) low back pain unless red flag features are found on patient history. Ultrasonography should be used for the evaluation of suspicious thyroid nodules identified incidentally on computed tomography.

Re-operative parathyroidectomy: How many positive localization studies are required?

BACKGROUND: Re-operative parathyroidectomy in patients with recurrent or persistent hyperparathyroidism can be challenging. We review our experience to determine the optimal number of localization studies prior to re-operation. METHODS: From 2001 to 2019, 251 patients underwent re-operative parathyroidectomy. Parathyroidectomies were stratified to 4 groups based upon the number of positive localization studies obtained: A) ZERO, B) 1-positive, C) 2-positive, D) 3-positive. RESULTS: The overall cure rate was 97%, where 201 single gland resections, 23 two-gland resections, 22 subtotal/total, and 5 forearm autograft resections were performed. Thirty-two patients had no positive studies (A), 172 patients had 1-positive (B), 42 patients had 2-positive (C), and 5 patients had 3-positive studies (D). There was no difference in surgical cure rates between groups (p = 0.71). The majority of patients had one or no positive imaging studies yet almost all still achieved cure. CONCLUSION: Successful re-operative parathyroidectomy can be performed with minimal pre-operative scans in certain clinical contexts.

Recommendations for nuclear neuroimaging of patients with neurological disorders in the COVID-19 era.

The novel coronavirus disease 2019 (COVID-19) pandemic has changed people's normal lives in a very short time causing extensive infections and mortality, which required the national health systems to be adapted to new situation. Changes in healthcare services included modifications of standard procedures in nuclear medicine departments in order to limit COVID-19 spreading and protect patients and personnel. Here, we recommend management of patients with neurological diseases and especially dementia and movement disorders, who are referred for neuroimaging with nuclear medicine techniques.

Challenges and priorities in skeletal, gastrointestinal, hepatobiliary, genitourinary and lung scintigraphy during the COVID-19 pandemic.

On December 29, 2019, a hospital in the City of Wuhan, Hubei Province, in Central China, admitted four individuals with pneumonia. The hospital reported this occurrence to the local center for disease control (CDC), which lead Wuhan CDC staff to initiate a field investigation with a retrospective search for pneumonia patients. On December 31, 2019, the World Health Organization (WHO) was alerted by the Chinese authorities for several cases of pneumonia of unknown origin in the City of Wuhan. On January 7, 2020, a novel virus was identified as the causative agent, belonging to the Coronaviridae family (Severe Acute Respiratory Syndrome Coronavirus 2, SARS-CoV-2). Within the same month, the virus spread to other provinces of China, as well as a number of neighbouring countries. On February 11, 2020, the WHO announced that the SARS-CoV-2 - caused infection would be called coronavirus disease 2019 (COVID-19). On February 15, 2020, the first death due to COVID-19 in Europe was reported; a Chinese tourist who died in France. The first COVID-19 case was diagnosed in Greece on February 26th. The WHO declared COVID-19 a pandemic on 11 March 2020. On March 12th, movie theaters, gyms and courtrooms were closed in Greece and on March 13th, with 190 confirmed cases and 1 death, malls, cafés, restaurants, bars, beauty parlors, museums and archaeological sites were also closed. So far, COVID-19 pandemic has affected the way people live and work globally, and has resulted in extreme strain on the healthcare systems worldwide. Most of the nuclear medicine studies are performed on an out-patient basis. Therefore, without effective implementation of the required preventive measures, there is a significant risk for viral transmission when visiting nuclear medicine departments, particularly in periods of high community spread.

Is dual-phase SPECT/CT with 99mTc-sestamibi better than single-phase SPECT/CT for lesion localization in patients with hyperparathyroidism?

This study aimed to establish an optimal protocol for Tc-sestamibi parathyroid imaging for lesion localization in patients with hyperparathyroidism (HPT).We retrospectively enrolled 35 consecutive patients who underwent dual-phase (at 10 minutes and 120 minutes) Tc-sestamibi parathyroid scintigraphy with single-photon emission computed tomography (SPECT)/computed tomography (CT). Twenty seven patients had primary HPT, and 8 had secondary or tertiary HPT. Three nuclear medicine physicians independently analyzed the parathyroid images for lesion localization at 9 predefined parathyroid locations using the following 4 different image sets blinded to the clinical information:All SPECT or SPECT/CT image sets were analyzed with dual-phase planar images. The image results were compared with the histopathological results after surgery.Dual-phase SPECT/CT showed the highest positive rate of 85.7% in the patient-based analysis and 13.7% in the location-based analysis. Of 35 patients, surgical pathological results were available in 21 (16 adenomas in 16 primary HPTs and 16 hyperplasias in 5 secondary or tertiary HPTs). Dual-phase SPECT/CT showed the sensitivity values of 100% and 84.4% in the patient-based and location-based analysis, respectively, which were the highest sensitivity values among all image sets. In the primary HPT subgroup, dual-phase SPECT/CT showed the highest sensitivity value of 93.8% in the location-based analyses, whereas dual-phase SPECT, early SPECT/CT, and delayed SPECT/CT showed the sensitivity values of 62.5%, 81.3%, and 81.3%, respectively. In the secondary or tertiary HPT subgroup, dual-phase SPECT/CT also showed the highest sensitivity value of 75.0%, whereas early SPECT/CT, delayed SPECT/CT, and dual-phase SPECT showed the sensitivity values of 43.8%, 56.3%, and 68.8%, respectively.Compared with dual-phase SPECT or single-phase SPECT/CT, the dual-phase SPECT/CT imaging protocol for Tc-sestamibi scintigraphy showed the highest positive rate and sensitivity, and was optimal for parathyroid lesion localization.

Emerging Attack and Management Strategies for Nuclear Medicine in Responding to COVID-19-ACNM Member Experience and Advice.

As the World Health Organization declared COVID-19 as "global pandemic," it is important for everyone, including nuclear medicine personnel, to know how to stop transmission, contain, and prevent the spread of COVID-19. We reach out to our ACNM (American College of Nuclear Medicine) international members from Wuhan, China and Singapore, who have participated in dealing with COVID-19 for the last 2 months, to learn from their lessons and experiences, so to provide advice to all ACNM members for their clinical practice and management strategies in responding to COVID-19.

Gastric emptying: methodology and normal ranges for two commonly used meals in the UK.

AIM: A recent audit has highlighted that there is a large variation in the way gastric emptying scintigraphy is performed, analysed and reported in the UK. In this study, we have established a comprehensive protocol on how to perform gastric emptying including normal ranges for two of the most widely used meals. A standardized scrambled egg sandwich was used as the main meal. Normal ranges were also established for oat porridge as an alternative gluten-free meal. We have calculated normal ranges for several functional parameters which may be used to assess gastric emptying. We hope that establishing a reliable normal range for these two simple and commonly used meals will encourage adoption of a universally accepted protocol for measurement of solid gastric emptying in the UK. METHOD: A total of 42 volunteers (20 male, 22 female, age range 22-68) with no history of gastrointestinal symptoms or diabetes were studied. Each volunteer fasted overnight and consumed two meals with similar nutritional composition on two separate days: scrambled eggs with two slices of bread were consumed on one day and gluten-free porridge (40 g in 200 mL whole milk) was consumed on a different day. Each meal was radiolabelled with 10 MBq of Tc-DTPA. Simultaneous anterior-posterior 2-min static images were acquired with the patient standing between the gamma camera detectors. Images were acquired every 5 min over a 2 hour period, followed by a single image at 3 hour. The data were modelled using a power-exponential function that allowed measurements of gastric emptying functional parameters including lag time, half-emptying time (HET), peak emptying rate, time-to-peak emptying (TPE) and exponential half-life (EHL). Three-hour retention was also calculated. Paired t-tests were used to compare the two meals and two-sample t-tests were used to assess gender-related differences. Regression analysis was used to assess correlation of the functional parameters with age and body habitus (body surface area, BSA). RESULTS: All gastric emptying functional parameters were significantly different between the two meals (P < 0.001). The normal range for lag time was 0-13 min for porridge and 1-34 min for scrambled egg. The normal range for HET was 18-73 min for porridge and 44-116 min for scrambled egg. The normal range for EHL was 21-57 min for porridge and 20-82 min for scrambled egg. The normal range for 3 hour retention was <7% for porridge and <17% for scrambled egg. Only weak significance was found for gender-related differences in gastric function for the two meals (0.05 < P < 0.10). Weak correlation was also observed for some functional parameters when plotted against age and BSA (0.05 < P < 0.10). CONCLUSION: We have established gastric emptying normal ranges for the two most commonly used meals in the UK. The normal ranges are meal specific and not interchangeable, with porridge showing significantly faster transit than scrambled egg for all measured parameters. Scrambled egg sandwich is the recommended meal for solid gastric emptying studies as it is more reproducible and more comparable to a normally consumed solid meal for our population. Porridge would be a suitable alternative for patients who are unable to eat egg sandwiches, for example, patients with egg allergy or gluten intolerance.

A Novel Noninvasive Method for Predicting Liver Fibrosis by Quantifying the Estrangement of Indocyanine Green Retention Rate and Tc-99m-diethylenetriamine-penta-acetic Acid-galactosyl Human Serum Albumin Scintigraphy.

BACKGROUND/AIM: Indocyanine green (ICG) clearance test is one of the most popular dynamic methods for evaluating preoperative liver function to avoid posthepatectomy liver failure (PHLF). Tc-99m-diethylenetriamine-penta-acetic acid-galactosyl human serum albumin scintigraphy (GSA) also facilitates the direct estimation of functional hepatocytes and can estimate the ICG retention rate (R15); however, in some cases, there is a discrepancy between results of a preoperative examination of ICG-R15 and the estimated ICG-R15 obtained by 99mTc-GSA (GSA-R15). This study evaluated the gap between ICG-R15 and GSA-R15 (ΔICG) for predicting background liver fibrosis in patients who underwent hepatectomy. PATIENTS AND METHODS: Sixty-four consecutive patients who underwent hepatectomy and preoperative ICG-R15 and GSA-R15 examinations from 2016 to 2019 were retrospectively evaluated. The gap between GSA-R15 and ICG-R15 was defined as ΔICG and the factors predicting liver fibrosis were investigated. RESULTS: In the pathologically-proven cirrhotic group, platelet counts were significantly lower and ΔICG values were significantly larger than those in the non-/early-cirrhotic group. A multivariate analysis identified a higher total bilirubin level, a higher AST level, and a larger ΔICG level as significant predictive factors for liver cirrhosis. CONCLUSION: Larger ΔICG was found to be an independent preoperative predictor of liver fibrosis and may positively contribute to decision-making before hepatectomy to avoid PHLF.

Reference values for quantitative parameters in renal scintigraphy with Tc-99m-MAG3.

BACKGROUND: Reference values are the basis for an increase of standardisation and examiner independence, and thus an improvement in the inter-institutional comparability. However for renal Mercaptoacetyltriglycin (MAG3)-scintigraphy the establishment of such values however did not find its way into clinical routine despite the convincing advantages. AIM: The aim was to establish reference values for the decisive quantitative parameters of MAG3 renal scintigraphy. The reference values should help to significantly improve and facilitate the interpretation of the examination results in everyday clinical practice. METHODS: We retrospectively evaluated all MAG3 renal scintigraphies performed in the Department of Nuclear Medicine, University Hospital Marburg between 01/2014 and 08/2017. The total sample of non-pathological renal scintigrafies included 247 patients aged between 25 days and 88 years. All investigtions were performed according to the present guidelines of the German Association for Nuclear Medicine. We analysed the ratio from pulse count rate after 20 minutes/Time (T) max and the Tmax separately. RESULTS: Reference values for the Tmax and 20 min/T(max) count ratio of the MAG3 renal scintigraphy were defined for all adults over 18 years and divided by age catogories. For children aged 0-0.5 years and 0.5-2 years reference values for Tmax were defined. CONCLUSION: The results show a high degree of consistency with the reference values screened out in previous studies. This underlines the reliability of the reference values as a diagnostic tool in clinical application. The defined values are clinically feasible and promise a simplified and improved interpretation of the MAG3 renal scintigraphy.

Assessment of an in-house phantom for the quality control of a clinical gamma camera.

OBJECTIVE: Since in-house phantoms may provide effective quality control for gamma cameras in clinical settings, this study aims to assess an in-house phantom designed to perform quality control tests of a gamma camera using locally available, affordable materials. This is of particular importance in developing countries where scientific support may not be readily available. MATERIALS AND METHODS: The phantom was made from cylindrical plexiglass with a diameter of 230 mm and thickness of 60 mm. The phantom design was based on NEMA recommendations and only used materials that are locally available and generally accessible to most nuclear medicine departments and require minimal engineering instruction. RESULTS: The phantom demonstrated high levels of reliability and accuracy. The integral uniformity range was between 1.93% and 2.40%. The differential uniformity ranged between 1.48% and 1.70%. CONCLUSION: This work demonstrates that in-house phantoms are capable of monitoring gamma camera performance. This approach is particularly useful when scientific support is not easily accessible and when commercial phantoms are not readily available.

Identification of Occult Adenomas in Primary Hyperparathyroidism With 18F-fluorocholine PET/CT. / Identificación de adenomas ocultos en hiperparatiroidismo primario con PET-TC 18F-fluorocolina.

INTRODUCTION: Single parathyroid adenomas are the most common cause of primary hyperparathyroidism (PHP) in our population. Parathyroidectomy is still the only potentially curative treatment and requires preoperative localization imaging studies to perform selective surgery. In patients with negative results on conventional tests, PET/CT has demonstrated higher sensitivity rates. METHODS: A prospective cohort study was designed, including 34 patients diagnosed with PHP between 2017 and 2019, candidates for surgery with negative preoperative localization tests with scintigraphy and MIBI SPECT/CT. All patients underwent PET/CT with 18F-Fluorocholine. The clinical, biochemical and postoperative outcome results were compared with a control group of 30 patients with positive standard tests. RESULTS: Hyperfunctional parathyroid tissue was detected in 85% of the patients that had undergone choline PET/CT. The selective resection of the adenoma identified in these patients achieved curative criteria in 87% of the cases without undergoing bilateral cervical surgical exploration. The preoperative levels of PTH, calcemia and gland weight were significantly lower in this group compared to the control group. No differences were identified in cure criteria or approach between the 2groups. CONCLUSION: In our study, choline PET/CT showed higher detection rates compared to the gold standard. The increase provides the opportunity to perform unilateral selected adenoma resection, especially in patients with smaller adenomas associated with lower calcemia and PTH levels and patients with previous cervical surgery.

The establishment and application of sialoscintigraphic reference values from patients with obstructive sialadenitis.

AIM: To evaluate feasibility of establishing a clinically applicable reference value through those unaffected salivary gland on sialoscintigraphic data obtained from patients presented with obstructive sialadenitis affected a single gland. MATERIALS AND METHODS: Ninety-one patients suffered from single salivary gland swelling, pain/tenderness and received sialoscintigraphic examinations were retrospectively enrolled. The quantitative data parameters, including the uptake ratio, maximal accumulation, maximal excretion, time to maximal (Tmax) and time to minimal (Tmin) activity of the affected and unaffected glands, were calculated for analysis. Data were also obtained and recorded for comparison from 50 patients who fulfill the American-European criteria for the diagnosis of Sjogren's syndrome. RESULTS: The maximal excretion appeared to be the best indicator for distinguishing affected and unaffected glands of obstructive diseases, for parotid and submandibular glands (P = 0.0002 and P < 0.0001, respectively). The area under the receiver-operating characteristic curve (AUC) is 0.82 for submandibular glands. In patients with Sjogren's syndrome, the maximal excretion and Tmin were the best parameters, for parotid (P = 0.002 and P < 0.0001, respectively) and submandibular glands (P < 0.0001 and P = 0.002, respectively). Uptake ratio was a good parameter for submandibular gland (P < 0.0001). The AUC of maximal excretion and uptake ratio for submandibular glands is 0.81 and 0.77, respectively. CONCLUSION: Quantitative data obtained from the unaffected glands of patients with obstructive sialadenitis could be used as reference values for the functional evaluation of salivary gland disorders with maximal excretion as one of the reliable parameters.