Performing [18F]MFBG Long-Axial-Field-of-View PET/CT Without Sedation or General Anesthesia for Imaging of Children with Neuroblastoma.

Meta-[123I]iodobenzylguanidine ([123I]MIBG) scintigraphy with SPECT/CT is the standard of care for diagnosing and monitoring neuroblastoma. Replacing [123I]MIBG with the new PET tracer meta-[18F]fluorobenzylguanidine ([18F]MFBG) and further improving sensitivity and reducing noise in a new long-axial-field-of-view (LAFOV) PET/CT scanner enable increased image quality and a faster acquisition time, allowing examinations to be performed without sedation or general anesthesia (GA). Focusing on feasibility, we present our first experience with [18F]MFBG LAFOV PET/CT and compare it with [123I]MIBG scintigraphy plus SPECT/CT for imaging in neuroblastoma in children. Methods: A pilot of our prospective, single-center study recruited children with neuroblastoma who were referred for [123I]MIBG scintigraphy with SPECT/CT. Within 1 wk of [123I]MIBG scintigraphy and SPECT/low-dose CT, [18F]MFBG LAFOV PET/ultra-low-dose CT was performed 1 h after injection (1.5-3 MBq/kg) without sedation or GA, in contrast to the 24-h postinjection interval needed for scanning with [123I]MIBG, the 2- to 2.5-h acquisition time, and the GA often needed in children less than 6 y old. Based on the spirocyclic iodonium-ylide precursor, [18F]MFBG was produced in a fully automated good manufacturing practice-compliant procedure. We present the feasibility of the study. Results: In the first paired scans of the first 10 children included (5 at diagnosis, 2 during treatment, 2 during surveillance, and 1 at relapse), [18F]MFBG PET/CT scan showed a higher number of radiotracer-avid lesions in 80% of the cases and an equal number of lesions in 20% of the cases. The SIOPEN score was higher in 50% of the cases, and the Curie score was higher in 70% of the cases. In particular, intraspinal, retroperitoneal lymph node, and bone marrow involvement was diagnosed with much higher precision. None of the children (median age, 1.6 y; range, 0.1-7.9 y) had sedation or GA during the PET procedure, whereas 80% had GA during [123I]MIBG scintigraphy with SPECT/CT. A PET acquisition time of only 2 min without motion artifacts was the data requirement of the 10-min acquisition time for reconstruction to provide a clinically useful image. Conclusion: This pilot study demonstrates the feasibility of performing [18F]MFBG LAFOV PET/CT for imaging of neuroblastoma. Further, an increased number of radiotracer-avid lesions, an increased SIOPEN score, and an increased Curie score were seen on [18F]MFBG LAFOV PET/CT compared with [123I]MIBG scintigraphy with SPECT/CT, and GA and sedation was avoided in all patients. Thus, with a 1-d protocol, a significantly shorter scan time, a higher sensitivity, and the avoidance of GA and sedation, [18F]MFBG LAFOV PET/CT shows promise for future staging and response assessment and may also have a clinical impact on therapeutic decision-making for children with neuroblastoma.

Clinical Evaluation of Deep Learning for Tumor Delineation on 18F-FDG PET/CT of Head and Neck Cancer.

Artificial intelligence (AI) may decrease 18F-FDG PET/CT-based gross tumor volume (GTV) delineation variability and automate tumor-volume-derived image biomarker extraction. Hence, we aimed to identify and evaluate promising state-of-the-art deep learning methods for head and neck cancer (HNC) PET GTV delineation. Methods: We trained and evaluated deep learning methods using retrospectively included scans of HNC patients referred for radiotherapy between January 2014 and December 2019 (ISRCTN16907234). We used 3 test datasets: an internal set to compare methods, another internal set to compare AI-to-expert variability and expert interobserver variability (IOV), and an external set to compare internal and external AI-to-expert variability. Expert PET GTVs were used as the reference standard. Our benchmark IOV was measured using the PET GTV of 6 experts. The primary outcome was the Dice similarity coefficient (DSC). ANOVA was used to compare methods, a paired t test was used to compare AI-to-expert variability and expert IOV, an unpaired t test was used to compare internal and external AI-to-expert variability, and post hoc Bland-Altman analysis was used to evaluate biomarker agreement. Results: In total, 1,220 18F-FDG PET/CT scans of 1,190 patients (mean age ± SD, 63 ± 10 y; 858 men) were included, and 5 deep learning methods were trained using 5-fold cross-validation (n = 805). The nnU-Net method achieved the highest similarity (DSC, 0.80 [95% CI, 0.77-0.86]; n = 196). We found no evidence of a difference between expert IOV and AI-to-expert variability (DSC, 0.78 for AI vs. 0.82 for experts; mean difference of 0.04 [95% CI, -0.01 to 0.09]; P = 0.12; n = 64). We found no evidence of a difference between the internal and external AI-to-expert variability (DSC, 0.80 internally vs. 0.81 externally; mean difference of 0.004 [95% CI, -0.05 to 0.04]; P = 0.87; n = 125). PET GTV-derived biomarkers of AI were in good agreement with experts. Conclusion: Deep learning can be used to automate 18F-FDG PET/CT tumor-volume-derived imaging biomarkers, and the deep-learning-based volumes have the potential to assist clinical tumor volume delineation in radiation oncology.

Potential Clinical Impact of LAFOV PET/CT: A Systematic Evaluation of Image Quality and Lesion Detection.

We performed a systematic evaluation of the diagnostic performance of LAFOV PET/CT with increasing acquisition time. The first 100 oncologic adult patients referred for 3 MBq/kg 2-[18F]fluoro-2-deoxy-D-glucose PET/CT on the Siemens Biograph Vision Quadra were included. A standard imaging protocol of 10 min was used and scans were reconstructed at 30 s, 60 s, 90 s, 180 s, 300 s, and 600 s. Paired comparisons of quantitative image noise, qualitative image quality, lesion detection, and lesion classification were performed. Image noise (n = 50, 34 women) was acceptable according to the current standard of care (coefficient-of-varianceref < 0.15) after 90 s and improved significantly with increasing acquisition time (PB < 0.001). The same was seen in observer rankings (PB < 0.001). Lesion detection (n = 100, 74 women) improved significantly from 30 s to 90 s (PB < 0.001), 90 s to 180 s (PB = 0.001), and 90 s to 300 s (PB = 0.002), while lesion classification improved from 90 s to 180 s (PB < 0.001), 180 s to 300 s (PB = 0.021), and 90 s to 300 s (PB < 0.001). We observed improved image quality, lesion detection, and lesion classification with increasing acquisition time while maintaining a total scan time of less than 5 min, which demonstrates a potential clinical benefit. Based on these results we recommend a standard imaging acquisition protocol for LAFOV PET/CT of minimum 180 s to maximum 300 s after injection of 3 MBq/kg 2-[18F]fluoro-2-deoxy-D-glucose.

Urokinase-type plasminogen activator receptor (uPAR) assessed by liquid biopsies and PET/CT for prognostication in head and neck cancer patients.

Strong prognostic biomarkers are lacking regarding the stratification of treatment and surveillance regimens in head and neck squamous cell carcinoma (HNSCC). The study aimed to assess the prognostic value of soluble urokinase-type plasminogen activator receptor in plasma (suPAR) compared to evaluation by uPAR-positron-emission-tomography (PET) in HNSCC patients. Plasma from 19 controls and 49 HNSCC patients referred to curatively intended radiotherapy (2017-2021) was collected pre-treatment and post-treatment (n = 37). Information on uPAR-PET was available from previous evaluation. Patient median suPAR was significantly higher pre- and post-treatment compared to controls (p = 0.013, p = 0.003) and increased significantly during radiotherapy (p = 0.003). Pre-treatment suPAR did not predict survival outcomes. Post-treatment suPAR significantly predicted RFS (HR = 6.67 (95% CI 1.44-30.9) p = 0.015), but not OS (HR = 3.29 (95% CI 0.882-12.3) p = 0.076) in univariate analysis. RFS prediction was maintained for post-treatment suPAR in multivariate analysis, including TNM-stage (HR = 6.62 (95% CI 1.40-31.4) p = 0.017). Pre-treatment uPAR-PET/CT and post-treatment suPAR was available in 24 patients. High uPAR-estimates on both modalities was significantly associated with poor RFS compared to patients with low uPAR-estimates (log-rank, p = 0.008). Patients with discordant uPAR-estimates (one-low/one-high) were at intermediate risk, although non-significant (p = 0.131). In conclusion, pre-treatment suPAR did not predict RFS or OS. Pre-treatment uPAR-PET and post-treatment suPAR predicted RFS.

Prognostic Value of Urokinase-Type Plasminogen Activator Receptor PET/CT in Head and Neck Squamous Cell Carcinomas and Comparison with 18F-FDG PET/CT: A Single-Center Prospective Study.

The aim of this phase II clinical trial (NCT02965001) was to evaluate the prognostic value of urokinase-type plasminogen activator receptor (uPAR) PET/CT with the novel ligand 68Ga-NOTA-AE105 in head and neck cancer and compare it with 18F-FDG. Methods: Patients with head and neck squamous cell carcinoma referred for curatively intended radiotherapy were eligible and prospectively included in this study. 68Ga-uPAR and 18F-FDG PET/CT were performed before initiation of curatively intended radiotherapy, and the SUVmax of the primary tumor was measured on both PET/CT studies by 2 independent readers. Relapse-free survival (RFS) and overall survival (OS) were calculated, and optimal cutoffs were established for 68Ga-uPAR and 18F-FDG PET independently and compared using log rank and Kaplan-Meier statistics, as well as univariate and multivariate analysis in a Cox proportional-hazards model. Results: In total, 57 patients were included and followed for a median of 33.8 mo (range, 2.30-47.2, mo). The median SUVmax of the primary tumors was 2.98 (range, 1.94-5.24) for 68Ga-uPAR and 15.7 (range, 4.24-45.5) for 18F-FDG. The optimal cutoffs for 68Ga-NOTA-AE105 SUVmax in the primary tumor were 2.63 for RFS and 2.66 for OS. A high uptake of 68Ga-NOTA-AE105 (SUVmax above cutoff) was significantly associated with poor RFS and OS (log-rank P = 0.012 and P = 0.022). 68Ga-NOTA-AE105 uptake in the primary tumor was significantly associated with poor RFS in univariate analysis (hazard ratio [HR], 8.53 [95% CI, 1.12-64.7]; P = 0.038), and borderline-associated with OS (HR, 7.44 [95% CI, 0.98-56.4]; P = 0.052). For 18F-FDG PET, the optimal cutoffs were 22.7 for RFS and 22.9 for OS. An 18F-FDG SUVmax above the cutoff was significantly associated with reduced RFS (log-rank P = 0.012) and OS (log-rank P = 0.000). 18F-FDG uptake was significantly associated with reduced RFS (HR, 3.27 [95% CI, 1.237-8.66]; P = 0.017) and OS (HR, 7.10 [95% CI, 2.60-19.4]; P < 0.001) in univariate analysis. In a multivariate analysis including 68Ga-uPAR SUVmax, 18F-FDG SUVmax, TNM stage, and p16 status, only 68Ga-uPAR SUVmax remained significant (HR, 8.51 [95% CI, 1.08-66.9]; P = 0.042) for RFS. For OS, only TNM stage and 18F-FDG remained significant. Conclusion: The current trial showed promising results for the use of 68Ga-uPAR PET SUVmax in the primary tumor to predict RFS in head and neck squamous cell carcinoma patients referred for curatively intended radiotherapy when compared with 18F-FDG PET, TNM stage, and p16 status. 68Ga-uPAR PET could potentially become valuable for identification of patients suited for deescalation of treatment and risk-stratified follow-up schemes.

Histiocytic Sarcoma: Challenging Course, Dismal Outcome.

Histiocytic sarcoma (HS) is a rare hematopoietic neoplasm derived from non-Langerhans histiocytic cells of the monocyte/macrophage system. With an incidence of 0.17/million individuals and a slight male preference, HS presents with a wide age distribution. Most commonly, it occurs as a primary malignancy. In approximately 25% of the cases a presumed transdifferentiation of a preexisting hematolymphoid disorder can be demonstrated. The clinical presentation varies from a localized solitary mass to severe disseminated disease often with extranodal involvement including skin, soft tissue, the gastrointestinal tract and the hematopoietic system. Systemic symptoms in terms of weight loss, fever and night sweats often occur. The diagnostic work-up of HS is extremely challenging due to the rarity of the disease as well as a wide differential diagnosis in terms of a histologic overlap with diverse mimics. No standardized treatment for HS exists and especially in a disseminated disease the clinical course is overly aggressive with a dismal outcome. The median overall survival from the time of diagnosis is approximately six months. We report a 43-year-old previously healthy Caucasian male admitted to our hospitals with abdominal pain and a feeling of fatigue. We demonstrate both the challenges of a correct diagnosis and an effective treatment as well as the aggressive nature of histiocytic sarcoma.

Generic multicriteria approach to determine the best precipitation agent for removal of biomacromolecules prior to non-targeted metabolic analysis.

The removal of biomacromolecules from biofluids decreases the sample complexity and lower electrospray suppression effects. Furthermore, it can increase the analysis sensitivity, precision, and selectivity. Often removal approaches evaluate the model based on a single criterion, like protein removed or response of one of few specific metabolites. In this study, we used a multicriteria approach to test the effect of using the solvents methanol and acetonitrile (organic solvent precipitation), trichloroacetic acid (acidic precipitation) and ammonium sulphate (salting out) to remove biomacromolecules from a downstream recovery process from a bacillus fermentation. The downstream recovery process intermediates were analysed using reversed-phase ultra-high-pressure liquid chromatography with electrospray ionisation and high-resolution time-of-flight mass spectrometry detection. To evaluate the pre-treatment agents the following multicriteria was applied i) practical considerations, ii) total amino acid in the precipitated pellet, iii) putative identification of the molecules removed or created by the different treatments, iv) coherence between high quality extracted ion chromatograms (repeatability of DW-CODA) and v) replicate consistency from principal component analysis score values obtained by using the CHEMometric analysis of sections of Selected Ion Chromatograms (CHEMSIC) method. This study presents a generic workflow to find the best pre-treatment for removing bio-macromolecules from biofluids with a multicriteria approach. In our case, the best protein removal strategy for downstream recovery intermediates was acetonitrile precipitation. This method showed high precision, created few artefact peaks compared to simple sample dilution, and mainly removed small peptides.

Overnight Admission After Total Ankle Replacement: Is It Safe?

To evaluate readmission, complication, and nonscheduled contact rates to the out-patient clinic within the first 3 months following total ankle replacement in patients planned for overnight admission. Data were collected retrospectively on all patients treated during the period the December 11, 2015 to the December 1, 2019 with 3 months of follow-up for all patients. In the study 116 patients were included. No difference in patient characteristics, readmission rates, complication rates or number of nonscheduled contacts to the outpatient clinic was found between patients discharged after 1 day when compared to those admitted >1 day. Around 58.6% was discharged as planned. The overall readmission and complication rates were 2.6% and 6.0% respectively, 20.7% had a nonscheduled contact to the out-patient clinic. No differences in prevalence of the different complications, reasons for readmission or reasons for contact to the out-patient clinic were found between overnight admission and inpatient admission. Total ankle placement with overnight admission is safe, but patient selection with a thorough plan for analgesics after discharge and optimal cast appliance is necessary.

[Ankle arthrosis].

Symptomatic ankle arthrosis affects 1-4% of the population, and the most common aetiology is post-traumatic. Symptoms include pain, swelling and reduced range of motion. Diagnosis is based on weight-bearing X-rays of the ankle joint, and treatment depends on the arthrosis grade and patient characteristics. Non-operative therapy, i.e. physiotherapy, analgesics, injection therapy and/or braces/orthoses is first-line treatment, as we argue in this review. Arthroscopy can be an effective treatment for some patients, but in case of severe arthrosis, osteotomies, total ankle replacement or arthrodesis may be necessary.

Primary Cardiac Intimal Sarcoma Visualized on 2-[18F]FDG PET/CT.

Primary cardiac tumors are extremely rare, with an incidence of 0.001-0.03%. Twenty-five percent of these tumors are malignant, with sarcomas accounting for approximately 95%. Cardiac intimal sarcoma is the least reported subtype of primary cardiac sarcoma. These endocardial mesenchymal tumors most often arise from great arterial vessels, and are rarely located in the heart. They often present with an aggressive clinical course and have a poor prognosis, with surgical resection with achievement of free margins being the mainstay of treatment. This emphasizes the importance of an early, correct diagnosis and timely intervention. We report a 60-year-old Caucasian male with several former cardiac surgical procedures due to congenital aortic stenosis, presenting with functional mitral stenosis/insufficiency and left ventricular outflow tract obstruction (LVOTO) due to massive masses in the left ventricle and atrium of the heart. Hybrid imaging with 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (2-[18F]FDG PET/CT) was performed prior to surgery to characterize the intracardiac masses and estimate tumor burden, as well as to identify a potential extracardiac primary malignancy.

The Effect of a Single Hyaluronic Acid Injection in Ankle Arthritis: A Prospective Cohort Study.

Nonoperative measures are often used as first line treatment in ankle osteoarthritis. One of these measures consists of hyaluronic acid injections in the affected ankle joint, but efficiency of this treatment is uncertain. The purpose of the study was to evaluate the effect on Self-reported Foot and Ankle Score, visual analog scale score at rest, and visual analog scale score at activity 6 months after a single dose of hyaluronic acid in patients with ankle osteoarthritis. Patients were included from December 2017 to March 2019. A single intra-articular injection of Cingal or MonoVisc was administered. Age, gender, osteoarthritis-grade, Self-reported Foot and Ankle Score, visual analog score at activity, and at rest before injection and after 6 months was registered. A total of 33 patients were included, with 14 lost to follow-up. Four were treated with MonoVisc and were excluded to reduce confounding. The remaining 15 patients were included for analysis. Median Self-reported Foot and Ankle Score remained unchanged (p = .06), whereas visual analog score at activity went from 7 to 6 (.02) and visual analog score at rest was reduced from 4 to 3 (.02). Subgroup analysis on arthrosis grade (grade I-II and III-IV) showed no statistically significant changes for all variables even though patients with grade III-IV arthrosis seemed to benefit more from the treatment. The results indicate that a single injection of hyaluronic acid is insufficient to produce at clinically relevant response after 6 months even though there is a high risk of underpowering because of a small patient population.

Mid-term results after treatment of complex talus osteochondral defects with HemiCAP implantation.

BACKGROUND: HemiCAP for complex osteochondral defects (OCDs) in talus has been on the market since 2008. Few follow-up studies exist. Patients with complex OCDs were followed for up to 81 months. METHODS: 31 consecutive patients were assessed preoperatively and at final follow-up, mean 50 months. All patients were treated with the HemiCAP®, Arthrosurface Inc., USA inlay. Inclusion criteria were complex OCDs of the medial or lateral talus dome. RESULTS: All outcome measures i.e. AOFAS, FAOS and NRS improved significantly. 71.8 % of the cohort were employed preoperatively. At final follow up 87.5% were employed. No revisions of the HemiCAP was performed, but 41,9% had supplementary surgery. 1 patient had a superficial infection otherwise no complications were found. Preoperative and final follow-up x-rays were analysed. CONCLUSIONS: Mid-term results after HemiCAP talus are good. Patient information and selection is mandatory due to the high numbers of additional surgeries following the HemiCap implantation.

How Old Do You Think I Am? Speech-Language Predictors of Perceived Age and Communicative Competence.

Purpose Spoken language serves as a primary means of social interaction, but speech and language skills change with age, a potential source of age-related stereotyping. The goals of this study were to examine how accurately age could be estimated from language samples, to determine which speech and language cues were most informative, and to assess the impact of perceived age on judgments of the speakers' communication skills. Method We analyzed narratives from 84 speakers aged 30-89 years to identify age-related differences and compared these differences to factors affecting perceptions of age and communicative competence. Three groups of raters estimated the speakers' ages and judged the quality of their communication: 44 listeners listened to audio-recorded narratives, 51 readers read transcripts of the narratives, and 24 voice raters listened to 10-s samples of speech extracted from one of the narratives. Results Older speakers spoke more slowly but showed minimal linguistic differences compared to younger speakers. Speakers' ages were estimated quite accurately, even from 10-s samples. Estimates were largely based on cues available in the acoustic signal-speech rate and vocal characteristics-so listeners were more accurate than readers. However, an overreliance on these cues also contributed to overestimates of speakers' ages. Communication ratings were not strongly related to perceived age but were influenced by various aspects of speech and language. In particular, speakers who produced longer narratives and spoke more quickly were judged to be better communicators. Conclusion Speakers tend to be judged on relatively superficial aspects of spoken language, in part because age-related change is most evident at these levels. Implications of these findings for age-related theories of stereotyping and speech-language intervention are discussed.

Concomitant Polymyalgia Rheumatica and Large-Vessel Vasculitis Visualized on 18F-FDG PET/CT.

Polymyalgia rheumatica (PMR) and large-vessel vasculitis (LVV) are related rheumatic diseases which are occasionally present concomitantly. PMR is characterized by synovitis and bursitis. In LVV, inflammation of the blood vessel wall is seen. Both disorders can be difficult to diagnose since patients often present non-specific symptoms and results of blood tests. The non-specific symptoms cannot always be distinguished from symptoms indicating an occult malignancy. We present a case of PMR and LVV in a Scandinavian man visualized on [18F]-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) with the presentation of typically affected sites of joints and arteries and with the same imaging modality ruling out occult malignancy.

Stewart-Treves Syndrome on the Lower Extremity Associated to Idiopathic Chronic Lymphedema Visualized on FDG PET/CT.

Angiosarcomas are highly malignant and rare tumors of vascular or lymphatic endothelial cell origin with a poor prognosis. Lymphangiosarcoma associated with chronic lymphedema is known as Stewart-Treves syndrome. Stewart-Treves syndrome is primarily described in patients with lymphedema of an upper extremity occurring after breast cancer surgery including radical axillary lymph node dissection and subsequent radiotherapy. It is rarely described in the presence of idiopathic chronic lymphedema of the lower extremities. We present a case of lymphangiosarcoma visualized on F-FDG PET/CT, where Stewart-Treves syndrome is secondary to probably a combination of idiopathic chronic lymphedema of the lower extremities and systemic immunosuppressive treatment.

Whole-Body 18F-FDG PET/CT Is Superior to CT as First-Line Diagnostic Imaging in Patients Referred with Serious Nonspecific Symptoms or Signs of Cancer: A Randomized Prospective Study of 200 Patients.

A fast-track pathway has been established in Denmark to investigate patients with serious nonspecific symptoms and signs of cancer (NSSC), who are not eligible to enter an organ-specific cancer program. The prevalence of cancer in this cohort is approximately 20%. The optimal screening strategy in patients with NSSC remains unknown. The aim of the study was to investigate whether 18F-FDG PET/CT was superior to CT as an initial imaging modality in patients with NSSC. In a randomized prospective trial, the imaging modalities were compared with regard to diagnostic performance. Methods: Two hundred patients were randomized 1:1 to whole-body 18F-FDG PET/CT or CT of the thorax and abdomen as the imaging modality. A tentative diagnosis was established after first-line imaging. The final referral diagnosis was adjudicated by the physician, when sufficient data were available. Results: One hundred ninety-seven patients were available for analysis because 3 patients withdrew consent before scanning. Thirty-nine (20%) patients were diagnosed with cancer, 10 (5%) with an infection, 15 (8%) with an autoimmune disease, and 76 (39%) with other diseases. In the remaining 57 patients (28%), no specific disease was found. 18F-FDG PET/CT had a higher specificity (96% vs. 85%; P = 0.028) and a higher accuracy (94% vs. 82%; P = 0.017) than CT. However, there were no statistically significant differences in sensitivity (83% vs. 70%) or negative predictive values (96% vs. 92%). No difference in days to final referral diagnosis according to randomization group could be shown (7.2 vs. 7.6 d). However, for the subgroups in which the imaging modality showed a suggestion of malignancy, there was a significant delay to final diagnosis in the CT group compared with the 18F-FDG PET/CT group (11.6 vs. 5.7 d; P = 0.02). Conclusion: Compared with CT, we found a higher diagnostic specificity and accuracy of 18F-FDG PET/CT for detecting cancer in patients with NSSC. 18F-FDG PET/CT should therefore be considered as first-line imaging in this group of patients.

Coronary artery calcium score and N-terminal pro-B-type natriuretic peptide as potential gatekeepers for myocardial perfusion imaging.

Myocardial perfusion imaging (MPI) holds an important place as non-invasive risk assessment in patients with intermediate risk of coronary heart disease (CHD). However, as much as 60-70% of MPI scans are normal. This study evaluates the role of coronary artery calcium scoring (CAC score) and NT-proBNP as potential gatekeepers for MPI. Patients with intermediate risk of CHD referred for standard MPI were included. CAC score and NT-proBNP were both assessed at the day of the stress study. Sensitivity, specificity and NPV for prediction of abnormal MPI scans were calculated for CAC, NT-proBNP and the combination hereof. A total of 190 patients were included (mean age 61 ± 12 years, 55% female) of whom 24% had known CHD. In all 30% of the scans were abnormal. CAC score achieved the highest AUC regardless of whether patients with known CHD were included or not [AUC 0·75 95% CI (0·66-0·84) and AUC 0·79 (0·68-0·91)]. As a singular variable, CAC score was the most potent predictor with a sensitivity of 85%, specificity of 39% and NPV 88%. The combination of CAC score<10 and NT-proBNP>26 reached a sensitivity of 98% and NPV 94%, where 8% of scans tentatively could be avoided. In patients referred for MPI with intermediate risk for CHD, a combination of CAC score and NT-proBNP could be used to identify a group of patients where MPI could be averted with a high degree of diagnostic safety.