Lost in space(s): Multimodal neuroimaging of disorientation along the Alzheimer's disease continuum.

Orientation is a fundamental cognitive faculty and the bedrock of the neurologic examination. Orientation is defined as the alignment between an individual's internal representation and the external world in the spatial, temporal, and social domains. While spatial disorientation is a recognized hallmark of Alzheimer's disease (AD), little is known about disorientation beyond space in AD. This study aimed to explore disorientation in spatial, temporal, and social domains along the AD continuum. Fifty-one participants along the AD continuum performed an ecological orientation task in the spatial, temporal, and social domains while undergoing functional MRI. Disorientation in AD followed a three-way association between orientation domain, brain region, and disease stage. Specifically, patients with early amnestic mild cognitive impairment exhibited spatio-temporal disorientation and reduced brain activity in temporoparietal regions, while patients with AD dementia showed additional social disorientation and reduced brain activity in frontoparietal regions. Furthermore, patterns of hypoactivation overlapped different subnetworks of the default mode network, patterns of fluorodeoxyglucose hypometabolism, and cortical atrophy characteristic of AD. Our results suggest that AD may encompass a disorder of orientation, characterized by a biphasic process manifesting as early spatio-temporal and late social disorientation. As such, disorientation may offer a unique window into the clinicopathological progression of AD. SIGNIFICANCE STATEMENT: Despite extensive research into Alzheimer's disease (AD), its core cognitive deficit remains a matter of debate. In this study, we investigated whether orientation, defined as the ability to align internal representations with the external world in spatial, temporal, and social domains, constitutes a core cognitive deficit in AD. To do so, we used PET-fMRI imaging to collect behavioral, functional, and metabolic data from 51 participants along the AD continuum. Our findings suggest that AD may constitute a disorder of orientation, characterized by an early spatio-temporal disorientation and followed by late social disorientation, manifesting in task-evoked and neurodegenerative changes. We propose that a profile of disorientation across multiple domains offers a unique window into the progression of AD and as such could greatly benefit disease diagnosis, monitoring, and evaluation of treatment response.

The role of additional chemotherapy prior to autologous HCT in patients with relapse/refractory DLBCL in partial remission-A retrospective multicenter study.

OBJECTIVES: To evaluate the role of additional chemotherapy before autologous hematopoietic cell transplantation (HCT) in patients with relapse/refractory diffuse large B-cell lymphoma (DLBCL) who achieve partial remission following first salvage therapy. METHODS: We conducted a multicenter retrospective study of all adult patients with DLBCL who underwent HCT between 2008 and 2020 and achieved partial response (PR) after the first salvage and were either referred directly to HCT (n = 47) or received additional salvage therapy before HCT (n = 22). RESULTS: Post-HCT CR rate and progression-free survival were comparable between the two groups (66% vs. 68%, p = .86 and median not reached vs. 10.2 months [95% confidence interval, CI 7.1-12.3], p = .27, respectively). Median overall survival (OS) and estimated 3-year OS favored patients who were directly referred to HCT (105.8 [95% CI 63-148] months vs. 14.5 [95% CI 0-44] months, p = .035, and 65% [95% CI 51%-75%] vs. 40% [95% CI 21%-53%], p = .035, respectively). In Cox regression model, while International Prognostic Index and primary refractory versus relapse disease did not impact OS, allocation to a second salvage regimen and older age were both associated with inferior survival (hazard ratio [HR] = 2.57 95% CI 1.1-5.8, p = .023 and HR = 1.04 95% CI 0.99-1.2, p = .064, respectively). CONCLUSIONS: Referring patients with chemotherapy-sensitive disease in PR directly to HCT is associated with better OS compared to those receiving additional lines of treatment.

Simultaneous multislice diffusion-weighted imaging versus standard diffusion-weighted imaging in whole-body PET/MRI.

OBJECTIVE: To compare standard (STD-DWI) single-shot echo-planar imaging DWI and simultaneous multislice (SMS) DWI during whole-body positron emission tomography (PET)/MRI regarding acquisition time, image quality, and lesion detection. METHODS: Eighty-three adults (47 females, 57%), median age of 64 years (IQR 52-71), were prospectively enrolled from August 2018 to March 2020. Inclusion criteria were (a) abdominal or pelvic tumors and (b) PET/MRI referral from a clinician. Patients were excluded if whole-body acquisition of STD-DWI and SMS-DWI sequences was not completed. The evaluated sequences were axial STD-DWI at b-values 50-400-800 s/mm2 and the apparent diffusion coefficient (ADC), and axial SMS-DWI at b-values 50-300-800 s/mm2 and ADC, acquired with a 3-T PET/MRI scanner. Three radiologists rated each sequence's quality on a five-point scale. Lesion detection was quantified using the anatomic MRI sequences and PET as the reference standard. Regression models were constructed to quantify the association between all imaging outcomes/scores and sequence type. RESULTS: The median whole-body STD-DWI acquisition time was 14.8 min (IQR 14.1-16.0) versus 7.0 min (IQR 6.7-7.2) for whole-body SMS-DWI, p < 0.001. SMS-DWI image quality scores were higher than STD-DWI in the abdomen (OR 5.31, 95% CI 2.76-10.22, p < 0.001), but lower in the cervicothoracic junction (OR 0.21, 95% CI 0.10-0.43, p < 0.001). There was no significant difference in the chest, mediastinum, pelvis, and rectum. STD-DWI detected 276/352 (78%) lesions while SMS-DWI located 296/352 (84%, OR 1.46, 95% CI 1.02-2.07, p = 0.038). CONCLUSIONS: In cancer staging and restaging, SMS-DWI abbreviates acquisition while maintaining or improving the diagnostic yield in most anatomic regions. KEY POINTS: • Simultaneous multislice diffusion-weighted imaging enables faster whole-body image acquisition. • Simultaneous multislice diffusion-weighted imaging maintains or improves image quality when compared to single-shot echo-planar diffusion-weighted imaging in most anatomical regions. • Simultaneous multislice diffusion-weighted imaging leads to superior lesion detection.

Clinical and pathological predictors for FDG-PET/CT avidity in patients with marginal zone lymphoma-a retrospective cohort study.

BACKGROUND: The clinical value of FDG-PET/CT for staging and monitoring treatment response in patients with aggressive lymphoma is well established. Conversely, its role in the assessment and management of marginal zone lymphoma (MZL) is less conclusive. We aimed to assess clinical, laboratory, and pathological predictors for FDG uptake in these patients, in an attempt to identify MZL patients whose management will benefit from this imaging modality. METHODS: In this single-center, retrospective cohort study, we included all adult patients diagnosed with MZL at the Rabin Medical Center between January 2006 and December 2020 who underwent FDG-PET/CT at the time of diagnosis. Primary outcomes were FDG avidity (defined as a visual assessment of at least moderate intensity), SUVmax, and SUVliver. Variables such as advanced clinical stage, primary disease site, hemoglobin level (Hb), platelet count (Plt), serum albumin, LDH level, ß-2 microglobulin, and Ki 67 index were evaluated univariate and multivariate analysis using logistic and linear regression models. Association between FDG avidity and progression-free and overall survival was evaluated using Kaplan-Meier curves and Cox regression analysis. RESULTS: A total of 207 MZL patients were included in this study, 76 of whom (36.7%) had FDG-avid disease. Baseline patients' characteristics such as age, gender, and comorbid conditions were similar between patients with and without significant FDG uptake. In a multivariate logistic regression model, non-gastric MALT (OR 4.2, 95% CI 1.78-10), Ki 67 index ≥ 15% (OR 3.64, 95% CI 1.36-9.76), and elevated LDH level (OR 8.6, 95% CI 3.2-22.8) were all associated with positive FDG avidity. In a multivariate linear regression model, a combination of advanced clinical stage, specific disease subtypes, LDH level, and Ki 67 index predicted the value of SUVmax (P value < 0.001; adjusted R2 = 33.8%) and SUVmax/SUVliver (P value < 0.001; adjusted R2 = 27%). Baseline FDG avidity was associated to PFS and OS only in univariate analyses. CONCLUSIONS: In this retrospective cohort study, we present prediction models for positive FDG uptake and SUVmax in MZL patients. These models aim to help clinicians choose patients suitable for incorporation of FDG-PET/CT for staging and monitoring disease and reduce the costs of redundant tests.

Autoimmune and inflammatory manifestations associated with acute myeloid leukemia with Trisomy 8-Case series and review of the literature.

AML can be associated with autoimmune or inflammatory phenomena (AIP) occurring prior, concomitantly, or after its diagnosis. Trisomy 8 is one of the most common cytogenetic abnormalities associated with AML. We describe three patients with AML, trisomy 8, and associated AIP and review the known literature on this association. All of our patients had major symptomatic relief when treated with leukemia-directed therapy and corticosteroids. AIP in AML may be an underdiagnosed phenomenon, particularly in patients with trisomy 8.

The clinical value of the endocarditis team: insights from before and after guidelines implementation strategy.

PURPOSE: To evaluate the impact of a multidisciplinary the "Endocarditis Team" (ET) on the course and outcome of infective endocarditis (IE) patients. METHODS: A retrospective before-after study, including hospitalized patients with definite IE, managed before (01.2013-12.2015) and after (01.2016-07.2019) the introduction of an ET. The primary outcomes were defined as 30-day and 1-year mortality and the secondary as conservative vs. invasive strategy, the interval from clinical suspicion of IE to the performance of echocardiography, utilization of multimodality evaluation, time to an invasive procedure, and the duration of hospitalization. RESULTS: Study population included 92 pre-ET and 128 post-ET implementation patients. Baseline characteristics were similar. During the post-ET period compared with pre-ET, we found higher rates of abscesses and extra-cardiac emboli (27.8% vs. 16.3%, p = 0.048); and a higher invasive procedures rate, including lead extraction (15.6% vs. 6.5%, p = 0.035) and noncardiac surgeries (14.8% vs. 6.5%, p = 0.05). Patients managed during the post-ET period had reduced short (8.5% vs. 17.4%, p = 0.048) and long-term mortality (Log-rank = 0.001). In multivariate analysis of risk factors for long-term mortality, period (pre- or post-ET) was not found to be significantly associated with the mortality. CONCLUSION: Establishment of an ET was associated with faster and more intensive evaluation of patients with IE. During the period of an ET activity, mortality rates were reduced compared with the previous period.

Diagnostic Performance of 68Ga Prostate-specific Membrane Antigen PET/MRI Compared with Multiparametric MRI for Detecting Clinically Significant Prostate Cancer.

Background Gallium 68 (68Ga) prostate-specific membrane antigen (PSMA) PET/MRI may improve detection of clinically significant prostate cancer (CSPC). Purpose To compare the sensitivity and specificity of 68Ga-PSMA PET/MRI with multiparametric MRI for detecting CSPC. Materials and Methods Men with prostate specific antigen levels of 2.5-20 ng/mL prospectively underwent 68Ga-PSMA PET/MRI, including multiparametric MRI sequences, between June 2019 and March 2020. Imaging was evaluated independently by two radiologists by using the Prostate Imaging Reporting and Data System (PI-RADS) version 2.1. Sensitivity and specificity for CSPC (International Society of Urological Pathology grade group ≥ 2) were compared for 68Ga-PSMA PET/MRI and multiparametric MRI by using the McNemar test. Decision curve analysis compared the net benefit of each imaging strategy. Results Ninety-nine men (median age, 67 years; interquartile range, 62-71 years) were included; 79% (78 of 99) underwent biopsy. CSPC was detected in 32% (25 of 78). For CSPC, specificity was higher for 68Ga-PSMA PET/MRI than multiparametric MRI (76% [95% CI: 62, 86] vs 49% [95% CI: 35, 63], respectively; P < .001). Sensitivity was similar (88% [95% CI: 69, 98] vs 92% [95% CI: 74, 99], respectively; P > .99). For PI-RADS 3 lesions, specificity was also higher for 68Ga-PSMA PET/MRI than for multiparametric MRI: 86% (95% CI: 73, 95) versus 59% (95% CI: 43, 74), respectively (P = .002). Decision curve analysis showed that biopsies targeted to PSMA uptake increased the net benefit of multiparametric MRI only among PI-RADS 3 lesions. The net benefit of targeted biopsy for a PI-RADS 3 lesion with PSMA uptake was higher across all threshold probabilities over 8%. The net benefit of targeted biopsy was similar for PI-RADS 4 and 5 lesions, regardless of PSMA uptake. Conclusions Gallium 68 prostate-specific membrane antigen PET/MRI improved specificity for clinically significant prostate cancer compared with multiparametric MRI, particularly in Prostate Imaging Reporting and Data System grade 3 lesions. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Williams and Estes in this issue.

Physiologic and hypermetabolic breast 18-F FDG uptake on PET/CT during lactation.

OBJECTIVE: To investigate the patterns of breast cancer-related and lactation-related 18F-FDG uptake in breasts of lactating patients with pregnancy-associated breast cancer (PABC) and without breast cancer. METHODS: 18F-FDG-PET/CT datasets of 16 lactating patients with PABC and 16 non-breast cancer lactating patients (controls) were retrospectively evaluated. Uptake was assessed in the tumor and non-affected lactating tissue of the PABC group, and in healthy lactating breasts of the control group, using maximum and mean standardized uptake values (SUVmax and SUVmean, respectively), and breast-SUVmax/liver-SUVmean ratio. Statistical tests were used to evaluate differences and correlations between the groups. RESULTS: Physiological uptake in non-breast cancer lactating patients' breasts was characteristically high regardless of active malignancy status other than breast cancer (SUVmax = 5.0 ± 1.7, n = 32 breasts). Uptake correlated highly between the two breasts (r = 0.61, p = 0.01), but was not correlated with age or lactation duration (p = 0.24 and p = 0.61, respectively). Among PABC patients, the tumors demonstrated high 18F-FDG uptake (SUVmax = 7.8 ± 7.2, n = 16), which was 326-643% higher than the mostly low physiological FDG uptake observed in the non-affected lactating parenchyma of these patients (SUVmax = 2.1 ± 1.1). Overall, 18F-FDG uptake in lactating breasts of PABC patients was significantly decreased by 59% (p < 0.0001) compared with that of lactating controls without breast cancer. CONCLUSION: 18F-FDG uptake in lactating tissue of PABC patients is markedly lower compared with the characteristically high physiological uptake among lactating patients without breast cancer. Consequently, breast tumors visualized by 18F-FDG uptake in PET/CT were comfortably depicted on top of the background 18F-FDG uptake in lactating tissue of PABC patients. KEY POINTS: • FDG uptake in the breast is characteristically high among lactating patients regardless of the presence of an active malignancy other than breast cancer. • FDG uptake in non-affected lactating breast tissue is significantly lower among PABC patients compared with that in lactating women who do not have breast cancer. • In pregnancy-associated breast cancer patients, 18F-FDG uptake is markedly increased in the breast tumor compared with uptake in the non-affected lactating tissue, enabling its prompt visualization on PET/CT.

Leukemic Phase of Histiocytic Sarcoma of the Digestive System: A Rare Manifestation of a Rare Disease.

Histiocytic sarcoma (HS) is a rare, malignant, and aggressive subtype of histiocytosis. We present an unusual case of aggressive HS presenting in the gastrointestinal tract and gallbladder that progressed after several lines of chemotherapy with a leukemic phase. We review the clinical, pathological, and molecular characteristics of HS in this case and review the literature on HS involving the digestive system as well as on overt leukemic phase of this disease. HS is often diagnosed at an advanced stage, and mortality is high. We discuss the therapeutic approach to patients with HS. We highlight the role of overexpression and somatic alterations in the RAF-MEK-ERK pathway in the pathogenesis of HS and discuss potential targeted approaches to treat these rare tumors.

Management implications of fluorodeoxyglucose positron emission tomography/magnetic resonance in untreated intrahepatic cholangiocarcinoma.

PURPOSE: Intrahepatic cholangiocarcinoma (ICC) is associated with a poor prognosis with surgical resection offering the best chance for long-term survival and potential cure. However, in up to 36% of patients who undergo surgery, more extensive disease is found at time of operation requiring cancellation of surgery. PET/MR is a novel hybrid technology that might improve local and whole-body staging in ICC patients, potentially influencing clinical management. This study was aimed to investigate the possible management implications of PET/MR, relative to conventional imaging, in patients affected by untreated intrahepatic cholangiocarcinoma. METHODS: Retrospective review of the clinicopathologic features of 37 patients with iCCC, who underwent PET/MR between September 2015 and August 2018, was performed to investigate the management implications that PET/MR had exerted on the affected patients, relative to conventional imaging. RESULTS: Of the 37 patients enrolled, median age 63.5 years, 20 (54%) were female. The same day PET/CT was performed in 26 patients. All patients were iCCC-treatment-naïve. Conventional imaging obtained as part of routine clinical care demonstrated early-stage resectable disease for 15 patients and advanced stage disease beyond the scope of surgical resection for 22. PET/MR modified the clinical management of 11/37 (29.7%) patients: for 5 patients (13.5%), the operation was cancelled due to identification of additional disease, while 4 "inoperable" patients (10.8%) underwent an operation. An additional 2 patients (5.4%) had a significant change in their operative plan based on PET/MR. CONCLUSIONS: When compared with standard imaging, PET/MR significantly influenced the treatment plan in 29.7% of patients with iCCC. TRIAL REGISTRATION: 2018P001334.

Comparison between pelvic PSMA-PET/MR and whole-body PSMA-PET/CT for the initial evaluation of prostate cancer: a proof of concept study.

OBJECTIVES: Despite the advantages of prostate-specific membrane antigen (PSMA)-PET/MR over PSMA-PET/CT, its relatively long scanning time and suboptimal PET attenuation correction necessitate careful assessment of the most appropriate setting for this type of study. We assessed lesion agreement between PSMA-PET/MR and PSMA-PET/CT in patients undergoing initial evaluation of prostate cancer. METHODS: This was a prospective study of consecutive patients with histological biopsy-proven prostate cancer who underwent pelvic PSMA-PET/MR followed by whole-body PSMA-PET/CT. All conspicuous PSMA-avid foci were counted on PSMA-PET/CT and PSMA-PET/MR with CT or MR correlation. Analysis was performed for intra-prostatic lesions, capsular invasion, seminal vesicle involvement and lymph node and bone involvement. Incidental and significant findings seen on PSMA-PET/CT outside the PSMA-PET/MR field of view were also analysed. Agreements between PSMA-PET/CT and PSMA-PET/MR findings were performed using Cohen's kappa test. RESULTS: Image analysis was performed on 140 patients (mean age, 67.3 ± 8.2 years). Agreement between PSMA PET/CT and PSMA-PET/MR was very good for intra-prostatic PSMA-avid foci (K = 0.85) and pelvic lymph nodes (K = 0.98), good for PSMA-avid bone metastases (K = 0.76) and fair for prostatic capsular invasion (K = 0.25) and seminal vesicle involvement (K = 0.31). Twelve patients (8.5%) had incidental findings and two patients (1.4%) had clinically significant findings. CONCLUSION: Limited pelvic PSMA-PET/MR has very good agreement with PET/CT regarding PSMA-avid prostatic, regional lymph nodes and bone lesions, and is superior to PET/CT with regard to capsular invasion and seminal vesicle involvement. KEY POINTS: • Limited pelvic PSMA-PET/MR is superior to whole-body PSMA-PET/CT in detecting extensions of localised disease, mainly due to the high soft tissue resolution of MR. • Limited pelvic PSMA-PET/MR may be useful for initial evaluation of histological biopsy-proven prostate cancer. • Further studies are warranted to evaluate limited pelvic PSMA-PET/MR for screening and active surveillance in selected populations.

Hybrid imaging of the abdomen and pelvis.

Accurate imaging is crucial for lesion detection in abdominal organs, for the noninvasive characterization of focal and diffuse abnormalities, and for surgical planning. To accomplish these tasks, several imaging modalities such as multidetector computer tomography (MDCT), magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) are used for abdominal imaging, providing important morphological, functional or metabolic information. More recently, PET/MRI has been gaining attention due to the possibility of combining high-resolution imaging with metabolic imaging. PET/MRI is a novel hybrid imaging technology that in the near future might play a pivotal role in the clinical management of oncologic and inflammatory abdominopelvic diseases. Despite the still limited number of published clinical studies, PET/MRI has been proven to be at least equivalent to PET/CT and to standalone MRI in a variety of oncologic disease. Moreover, in selected and focused clinical studies, it has been proven to outperform current standard of care imaging, for example, in evaluating cholangiocarcinomas, liver metastases, untreated and treated rectal cancer. This has also had an impact on therapeuticmanagement in some studies. Therefore in some institutions, including those of the authors, PET/MRI is becoming the new standard imaging modality in staging treatment-naïve intrahepatic massforming cholangiocarcinomas and prior to complicated hepatic surgery.

[Hybrid imaging of the abdomen and pelvis. German version]. / Hybridbildgebung bei abdominellen Erkrankungen.

Accurate imaging is crucial for lesion detection in abdominal organs, for the noninvasive characterization of focal and diffuse abnormalities, and for surgical planning. To accomplish these tasks, several imaging modalities such as multidetector computer tomography (MDCT), magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) are used for abdominal imaging, providing important morphological, functional or metabolic information. More recently, PET/MRI has been gaining attention due to the possibility of combining high-resolution imaging with metabolic imaging. PET/MRI is a novel hybrid imaging technology that in the near future might play a pivotal role in the clinical management of oncologic and inflammatory abdominopelvic diseases. Despite the still limited number of published clinical studies, PET/MRI has been proven to be at least equivalent to PET/CT and to stand-alone MRI in a variety of oncologic disease. Moreover, in selected and focused clinical studies, it has been proven to outperform current standard of care imaging, for example, in evaluating cholangiocarcinomas, liver metastases, untreated and treated rectal cancer. This has also had an impact on therapeutic management in some studies. Therefore in some institutions, including those of the authors, PET/MRI is becoming the new standard imaging modality in staging treatment-naïve intrahepatic mass-forming cholangiocarcinomas and prior to complicated hepatic surgery.

FDG PET/CT as a diagnostic and prognostic tool for the evaluation of marginal zone lymphoma.

We evaluated the role of 18-fluoro-2-deoxy-d-glucose positron emission tomography ([18F] FDG-PET) with computed tomography (CT) (PET/CT) as a diagnostic and prognostic tool in newly diagnosed marginal zone lymphoma (MZL) patients. This is a retrospective cohort study of patients with newly diagnosed MZL, treated with immunotherapy, chemotherapy regimens, surgery, or Helicobacter pylori eradication between 2008 and 2016 in a single tertiary center. Only patients who had a pretreatment PET/CT (P-PET/CT) were included. P-PET/CT, interim (I-PET/CT), and end-of-treatment PET/CT (E-PET/CT) studies were reviewed. P-PET/CT results were reported using two methods of evaluation, qualitative and semi quantitative: visual assessment (VAS) and maximal standardized uptake value (SUVmax), and I-PET and E-PET results were reported by Deauville 5-point score (DS) evaluation as well. Avidity of PET/CT was defined as abnormal uptake in any of these methods. The primary outcome was the prognostic role of P-PET/CT, I-PET/CT, and E-PET/CT on progression-free survival (PFS) and overall survival (OS). Data of 196 patients with MZL were identified, 110 of which had P-PET/CT and were included in this analysis. Median age was 67 years (range 18-93). The median follow-up period was 63 months (range 3-278). The median OS and PFS for the whole cohort were 63 (interquartile range 39-85) and 60 (interquartile range 37-76) months, respectively. The avidity of PET at baseline for the whole cohort was 70% (77/110 patients), for MALT lymphoma, 62.5% (40/64 patients), for NMZL, 76.4% (13/17 patients), and for SMZL, 82.7% (24/29 patients). When adjusted for IPI, sex, and comorbidities, positive E-PET/CT was associated with reduced PFS with a hazard ratio (HR) of 3.4 (95% CI, 1.27-9.14, P = 0.02). Positive E-PET/CT did not correlate with OS. However, there were only three events. P-PET/CT was not predictive of PFS or OS. Our study demonstrates that above 70% of MZL are FDG avid. Positive E-PET/CT is a strong prognostic factor for PFS.

Spontaneous Regression of Hodgkin Lymphoma: Case Report and Review of the Literature.

Spontaneous regression of Hodgkin lymphoma (HL) is a rare event. We describe a 32-year-old woman with spontaneous regression of HL and review the literature. The patient presented with cervical lymphadenopathy and was diagnosed with stage IIA classical HL. The patient refused to receive any treatment for her disease. Positron emission tomography/computed tomography carried out 2 years later showed complete regression of the lymphadenopathy, without pathological uptake of fluorodeoxyglucose. At the last follow-up, 3.5 years after the initial presentation, the patient is with no evidence of disease. During workup for the HL, concomitant papillary thyroid carcinoma was diagnosed, for which the patient refused treatment as well. The thyroid malignancy has remained stable throughout the follow-up.

The role of F18-fluorocholine positron emission tomography/magnetic resonance imaging in localizing parathyroid adenomas.

PURPOSE: Preoperative localization of a parathyroid adenoma is usually obtained by the combination of ultrasound and scintigraphy with technetium-99m methoxyisobutylisonitrile. We evaluated the role of F18-fluorocholine in neck positron emission tomography/magnetic resonance imaging as a novel tool for localizing parathyroid adenomas. METHODS: Patients with primary hyperparathyroidism were recruited from February 2016 to August 2017 and F18-fluorocholine positron emission tomography/magnetic resonance imaging was performed to localize the parathyroid adenoma prior to surgery. We compared sensitivity and accuracy of this modality with ultrasound and technetium-99m methoxyisobutylisonitrile scintigraphy using the verified location of the diseased parathyroid as found in surgery. RESULTS: Nineteen patients were included in our study (15 women and 4 men, mean age 60.5 ± 9.8 years). Positron emission tomography/magnetic resonance imaging precisely localized the pathologic parathyroid gland in 16/19 cases (84.2%) and predicted the diseased side in 19/19 cases (100%). Ultrasound and technetium 99 m methoxyisobutylisonitrile sestamibi scintigraphy predicted the location of the parathyroid adenoma in 16/19 (84.2%) and 14/19 (74%), respectively. In 3/19 patients, positron emission tomography/magnetic resonance imaging localized the parathyroid adenoma where as other modalities failed. Positron emission tomography/magnetic resonance imaging was more accurate when compared to each modality separately (p < 0.001, p = 0.017), however, when comparing the three modalities all together no differences were found (p = 0.506). CONCLUSIONS: Localizing parathyroid adenomas with F18-fluorocholine positron emission tomography/magnetic resonance imaging may be a promising secondary imaging modality.

The Role of 18F-Fluorodeoxyglucose Positron-Emission Tomography/Computed Tomography in the Diagnosis of Postoperative Hardware-Related Spinal Infections.

BACKGROUND: Implant-related spinal infections are a surgical complication associated with high morbidity. Due to infection, hardware removal may be necessary, which could lead to pseudarthrosis and the loss of stability and alignment. OBJECTIVES: To evaluate the accuracy and diagnostic value of 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (18F-FDG PET/CT) in the workup of patients with suspected implant-related infections of the spine and to assess the clinical impact of PET/CT results on the management of these infections. METHODS: The study included nine consecutive patients with a history of spinal surgery who underwent PET/CT for evaluation of suspected spinal implant related infection. All imaging studies were performed between January 2011 and December 2013. All 18F-FDG PET/CT scans were performed on an 8 slice PET/CT following an 18F-FDG injection. Images were scored both visually and semi-quantitatively by a radiology expert. Results were compared to additional imaging studies when available, which were correlated to clinical and bacteriological findings allowing calculation of sensitivity, specificity and accuracy. RESULTS: Among the patients, five experienced hardware-related spinal infection. 18F-FDG PET/CT sensitivity was 80%, specificity 100%, and accuracy 88.9%. One scan produced a false negative; however, a second PET/CT scan revealed an infection. CONCLUSIONS: PET/CT was found to be valuable for the diagnosis of postoperative hardware-related spinal infection, especially when other imaging modalities were uninformative or inconclusive. As such, PET/CT could be useful for management of infection treatment.

Quantitative characterisation of clinically significant intra-prostatic cancer by prostate-specific membrane antigen (PSMA) expression and cell density on PSMA-11.

OBJECTIVES: To quantitatively characterize clinically significant intra-prostatic cancer (IPC) by prostate-specific membrane antigen (PSMA) expression and cell density on PSMA-11 positron emission tomography/magnetic resonance (PET/MR). METHODS: Retrospective study approved by the institutional review board with informed written consent obtained. Patients with a solitary, biopsy-proven prostate cancer, Gleason score (GS) ≥7, presenting for initial evaluation by PET/computerised tomography (PET/CT), underwent early prostate PET/MR immediately after PSMA-11 tracer injection. PET/MR [MRI-based attenuation correction (MRAC)] and PET/CT [CT-based AC (CTAC)] maximal standardised uptake value (SUVmax) and minimal and mean apparent diffusion coefficient (ADCmin, ADCmean; respectively) in normal prostatic tissue (NPT) were compared to IPC area. The relationship between SUVmax, ADCmin and ADCmean measurements was obtained. RESULTS: Twenty-two patients (mean age 69.5±5.0 years) were included in the analysis. Forty-four prostate areas were evaluated (22 IPC and 22 NPT). Median MRAC SUVmax of NPT was significantly lower than median MRAC SUVmax of IPC (p < 0.0001). Median ADCmin and ADCmean of NPT was significantly higher than median ADCmin and ADCmean of IPC (p < 0.0001). A very good correlation was found between MRAC SUVmax with CTAC SUVmax (rho = -0.843, p < 0.0001). A good inverse relationship was found between MRAC SUVmax and CTAC SUVmax with ADCmin (rho = -0.717, p < 0.0001 and -0.740, p < 0.0001; respectively; Z = 0.22, p = 0.82, NS) and with MRAC SUVmax and ADCmean (rho = -0.737, p < 0.0001). CONCLUSIONS: PET/MR SUVmax, ADCmin and ADCmean are distinct biomarkers able to differentiate between IPC and NPT in naïve prostate cancer patients with GS ≥ 7. KEY POINTS: • PSMA PET/MR metrics differentiate between normal and tumoural prostatic tissue. • A multi-parametric approach combining molecular and anatomical information might direct prostate biopsy. • PSMA PET/MR metrics are warranted for radiomics analysis.

The Association of Helicobacter pylori Seropositivity with All-Cause Mortality among Colorectal Cancer Patients Undergoing PET/CT Scans.

BACKGROUND: Evidence has been emerging that Helicobacter pylori may also impact colorectal cancer (CRC). Positron emission tomography/computed tomography (PET/CT) imaging can predict overall survival in CRC patients. OBJECTIVES: To determine a possible association between H. pylori seropositivity and all-cause mortality among CRC patients evaluated by PET/CT scans. METHODS: This prospective cohort study was comprised of 110 consecutive CRC patients who had undergone a PET/CT evaluation in a tertiary academic medical center. Data included demographics, body mass index (BMI), tumor node metastasis stage at diagnosis, treatment, time from diagnosis to PET/CT, and PET/CT findings. All patients were tested for anti-H. pylori immunoglobulin G (IgG) antibodies and followed for 36 months from the day of the PET/CT scan. Mortality was documented. Univariate and multivariate Cox regression was used to estimate the hazard ratio (HR) of H. pylori serological status. RESULTS: During the follow-up period, of the 110 CRC patients 41 (37.3%) died and 69 (62.7%) survived. Of the 41 patients, 26 (63.4%) were H. pylori seropositive and 15 (36.6%) were seronegative. Multivariate analysis showed that H. pylori seropositivity was associated with increased mortality (HR 3.46, 95% confidence interval 1.63-7.32), stage IV at diagnosis, metastatic disease found on PET/CT, longer time from diagnosis to PET/CT, lower BMI, and older age. CONCLUSIONS: Our findings suggest that H. pylori infection may be a risk factor for all-cause mortality among CRC patients who are evaluated by PET/CT. Multicenter studies with larger patient groups are needed to confirm our findings.

Dynamic 11C-Choline PET / CT for the primary diagnosis of prostate cancer.

OBJECTIVES: To test the ability of dynamic 11C-PET / CT to discriminate cancerous tissue from background tissue in patients with localized prostate cancer. MATERIALS AND METHODS: Twenty-four consecutive patients with prostate cancer were prospectively evaluated with dynamic 11C-choline PET / CT prior to radical prostatectomy. The PET / CT scan was divided into 18 sequences of 5 seconds each, followed by 9 sequences of 60 seconds each. Whole-mount sections of harvested prostates served as reference standards. Volumes of interest were positioned on the dynamic PET / CT images and the following quantitative variables were calculated: perfusion coefficient (K1), washout constant (K2), area under the curve (AUC) at 175 and 630 seconds, and average and maximum standardized uptake values (SUVavg, and SUVmax). Wilcoxon signed-ranks test was used to compare benign and cancerous areas of the prostate. RESULTS: Areas of cancerous tissue were characterized by higher SUVavg and SUVmax than areas of benign tissue (3.67 ± 2.7 vs. 2.08 ± 1.3 and 5.91 ± 4.4 vs. 3.71 ± 3.7, respectively, P < 0.001), in addition to a higher K1 (0.95 ± 0.58 vs. 0.43 ± 0.24, P < 0.001) and greater cumulative tracer uptake, represented by the AUC at 175 and 630 seconds (P <0.001). No associations were found between dynamic parameters and preoperative prostate specific antigen level or Gleason score. CONCLUSIONS: In this pilot study, 11C-choline PET / CT demonstrated increased tracer uptake with higher values of static and dynamic parameters in areas of prostate cancer compared to areas of benign tissue. Larger studies are warranted to validate these results and examine the potential applicability of 11C-choline dynamic PET / CT for the diagnosis of prostate cancer.