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The novel coronavirus disease 2019 (COVID-19) emerged as the source of a global pandemic in late 2019 and early 2020 and quickly spread throughout the world becoming one of the worst pandemics in recent history. This chapter reviews the most up to date radiological literature and outlines the utility of thoracic imaging in COVID-19, defining both the common and the less typical imaging appearances during the acute and subacute phases of COVID-19. The short term complications and the long term sequela will also be discussed in the context of radiology, including pulmonary emboli, acute respiratory distress syndrome, superimposed infections, barotrauma, cardiac manifestations, pulmonary parenchymal scarring and fibrosis.

PURPOSE To describe the feasibility, safety and short-term results of prostatic artery embolization (PAE) performed with adjunctive coil embolization of the main prostatic arteries (PA) following particle embolization. MATERIALS AND METHODS A total of 95 patients who underwent PAE with adjunctive bilateral coil embolization of the PAs following particle embolization between September 2018 and May 2021 were included. The patients had a mean prostate size of 115 ± 64 ml, 18/95 with hematuria symptoms, and 16/95 with indwelling urinary catheters. Coil embolization was performed in the main PAs prior to the bifurcation into the anteromedial and posterolateral branches using detachable microcoils. International Prostate Symptoms Score (IPSS), quality of life (QOL), maximum flow rate (Qmax) and adverse events were recorded. RESULTS IPSS were improved by - 11.2 ± 7.9 (n = 49, P

Objective To compare transperineal (TP-TBx) and transrectal (TR-TBx) targeted prostate biopsy in a prospective non randomized single surgeon series of MR/US fusion-guided targeted biopsy performed using an electromagnetic tracking platform (NCT04026763). Materials and Methods In this single-institution prospective study, 168 patients who underwent transperineal systematic 12-core biopsy and TP-TBx with electromagnetic tracking (UroNav, Invivo, Gainesville, FL) were compared to 211 patients who underwent a similar procedure by a transrectal approach. Univariate and multivariate analyses were used to assess if biopsy technique impacted all cancer detection rates or clinically significant (Gleason score >3+4) cancer detection rates. Results Patients who underwent TP-TBx were older (68 vs 65 y, P = .014), with a slightly higher rate of PI-RADSv2.0 score (39% vs 28%, P = .039) and higher lesion volume on mpMRI (0.54 vs 0.41 cc, P = .039). The rates of CS disease detection by TP-TBx and TR-TBx were 59% and 54%, respectively. In a multivariate analysis adjusting for PSA, previous biopsy status, prostate volume, PI-RADS score, lesion volume, and lesion location, there was no statistically significant difference in likelihood to detect any PCa (OR, 0.98; 95% CI, 0.56-1.71; P = .940) or CS PCa (OR, 0.94, 95% CI, 0.58-1.51; P = .791). Conclusion Transperineal targeted biopsy with electromagnetic-tracking is comparable to the transrectal fusion-guided approach in the detection of any PCa and csPCa cancer.

Purpose We describe the presenting characteristics and hospital course of 11 novel coronavirus (COVID-19) patients who developed spontaneous subcutaneous emphysema (SE) with or without pneumomediastinum (SPM) in the absence of prior mechanical ventilation. Materials and methods A total of 11 non-intubated COVID-19 patients (8 male and 3 female, median age 61 years) developed SE and SPM between March 15 and April 30, 2020 at a multi-center urban health system in New York City. Demographics (age, gender, smoking status, comorbid conditions, and body-mass index), clinical variables (temperature, oxygen saturation, and symptoms), and laboratory values (white blood cell count, C-reactive protein, D-dimer, and peak interleukin-6) were collected. Chest radiography (CXR) and computed tomography (CT) were analyzed for SE, SPM, and pneumothorax by a board-certified cardiothoracic-fellowship trained radiologist. Results Eleven non-intubated patients developed SE, 36% (4/11) of whom had SE on their initial CXR. Concomitant SPM was apparent in 91% (10/11) of patients, and 45% (5/11) also developed pneumothorax. Patients developed SE on average 13.3 days (SD: 6.3) following symptom onset. No patients reported a history of smoking. The most common comorbidities included hypertension (6/11), diabetes mellitus (5/11), asthma (3/11), dyslipidemia (3/11), and renal disease (2/11). Four (36%) patients expired during hospitalization. Conclusion SE and SPM were observed in a cohort of 11 non-intubated COVID-19 patients without any known cause or history of invasive ventilation. Further investigation is required to elucidate the underlying mechanism in this patient population., Highlights • COVID-19 patients were observed to form subcutaneous air and pneumomediastinum in the absence of mechanical ventilation. • Patients in this cohort presented mainly with respiratory symptoms including mild hypoxia, but otherwise stable vital signs. • On initial presentation, all patients demonstrated abnormalities in inflammatory markers. • On initial presentation, all patients demonstrated abnormalities in inflammatory markers.

Chest tube placement is a commonly performed procedure, but it is not without complication. Our case report discusses a unique complication of chest tube placement with the use of minimally invasive techniques in order to treat it.

Background Chest radiography has not been validated for its prognostic utility in evaluating patients with coronavirus disease 2019 (COVID-19). Purpose To analyze the prognostic value of a chest radiograph severity scoring system for younger (nonelderly) patients with COVID-19 at initial presentation to the emergency department (ED); outcomes of interest included hospitalization, intubation, prolonged stay, sepsis, and death. Materials and Methods In this retrospective study, patients between the ages of 21 and 50 years who presented to the ED of an urban multicenter health system from March 10 to March 26, 2020, with COVID-19 confirmation on real-time reverse transcriptase polymerase chain reaction were identified. Each patient's ED chest radiograph was divided into six zones and examined for opacities by two cardiothoracic radiologists, and scores were collated into a total concordant lung zone severity score. Clinical and laboratory variables were collected. Multivariable logistic regression was used to evaluate the relationship between clinical parameters, chest radiograph scores, and patient outcomes. Results The study included 338 patients: 210 men (62%), with median age of 39 years (interquartile range, 31-45 years). After adjustment for demographics and comorbidities, independent predictors of hospital admission (n = 145, 43%) were chest radiograph severity score of 2 or more (odds ratio, 6.2; 95% confidence interval [CI]: 3.5, 11; P < .001) and obesity (odds ratio, 2.4 [95% CI: 1.1, 5.4] or morbid obesity). Among patients who were admitted, a chest radiograph score of 3 or more was an independent predictor of intubation (n = 28) (odds ratio, 4.7; 95% CI: 1.8, 13; P = .002) as was hospital site. No significant difference was found in primary outcomes across race and ethnicity or those with a history of tobacco use, asthma, or diabetes mellitus type II. Conclusion For patients aged 21-50 years with coronavirus disease 2019 presenting to the emergency department, a chest radiograph severity score was predictive of risk for hospital admission and intubation. © RSNA, 2020 Online supplemental material is available for this article.

Objective To evaluate the ability to detect clinically significant prostate cancer (PCa) using a novel electromagnetically (EM) tracked transperineal magnetic resonance imaging (MRI)/ultrasonography (US) fusion-guided targeted biopsy (transperineal TBx) platform and the impact of inter-reader variability on cancer detection. Materials and methods A total of 176 patients with suspicious lesions detected on multiparametric MRI (mpMRI) underwent a systematic modified Barzel template biopsy (12-core) transperineal biopsy (transperineal SBx) and transperineal TBx with EM tracking (UroNav; Philips Healthcare, Best, the Netherlands) in the same setting. Cancer detection rates (CDRs) were stratified by Prostate Imaging Reporting and Data System (PI-RADS) v2 scores and compared with Fisher's exact test. Area under the curve (AUC) was calculated for prostate-specific antigen (PSA), PSA density (PSAD), PI-RADS score, and subgroup analysis of individual readers' PI-RADS scores with respect to overall CDR and clinically significant CDR. Results The overall CDR was 76.7% (135/176), of which 76.3% (103/135) was clinically significant PCa. Among the 135 patients with PCa, transperineal TBx detected 90.4% of cases (122/135), either alone or in combination with transperineal SBx. The remaining 9.6% of cases (13/135) missed by transperineal TBx were diagnosed by transperineal SBx alone, of which three were clinically significant. Conversely, transperineal SBx missed 14% of cases (19/135), 14 of which were clinically significant PCa. Sensitivities for transperineal TBx and transperineal SBx were 90.4% and 85.9%, respectively. On a per-lesion basis, PI-RADS score (AUC 0.74) outperformed both PSA (AUC 0.59) and PSAD (AUC 0.63) in discriminating clinically significant from non-clinically significant PCa on transperineal TBx. Although not formally statistically tested, AUCs amongst different mpMRI readers appeared to display considerable variability. There were no adverse events, including sepsis. Conclusions Electromagnetically tracked transperineal TBx of MRI-visible lesions enhanced the ability of transperineal SBx to detect PCa, with greater sensitivity for clinically significant disease. These findings suggest transperineal TBx is a safe, alternative fusion platform for patients with a suspicious lesion on prostate MRI. The assessment of inter-reader variability, in conjunction with prediction of clinically significant PCa and CDR, is an important first step for quality control in implementing an MRI-based screening programme.

Background Recent studies have demonstrated a complex interplay between comorbid cardiovascular disease, COVID-19 pathophysiology, and poor clinical outcomes. Coronary artery calcification (CAC) may therefore aid in risk stratification of COVID-19 patients. Methods Non-contrast chest CT studies on 180 COVID-19 patients ≥ age 21 admitted from March 1, 2020 to April 27, 2020 were retrospectively reviewed by two radiologists to determine CAC scores. Following feature selection, multivariable logistic regression was utilized to evaluate the relationship between CAC scores and patient outcomes. Results The presence of any identified CAC was associated with intubation (AOR: 3.6, CI: 1.4–9.6) and mortality (AOR: 3.2, CI: 1.4–7.9). Severe CAC was independently associated with intubation (AOR: 4.0, CI: 1.3–13) and mortality (AOR: 5.1, CI: 1.9–15). A greater CAC score (UOR: 1.2, CI: 1.02–1.3) and number of vessels with calcium (UOR: 1.3, CI: 1.02–1.6) was associated with mortality. Visualized coronary stent or coronary artery bypass graft surgery (CABG) had no statistically significant association with intubation (AOR: 1.9, CI: 0.4–7.7) or death (AOR: 3.4, CI: 1.0–12). Conclusion COVID-19 patients with any CAC were more likely to require intubation and die than those without CAC. Increasing CAC and number of affected arteries was associated with mortality. Severe CAC was associated with higher intubation risk. Prior CABG or stenting had no association with elevated intubation or death.

Radioembolization with yttrium-90 microspheres has a growing role in the interventional oncological management of patient's with hepatocellular carcinoma. Patients with Barcelona Clinic Liver Cancer early or intermediate hepatocellular carcinoma may be offered radioembolization in order to control tumor burden while awaiting a transplant organ-referred to as "bridging" a patient to transplantation-or to reduce tumor burden such that patients will subsequently meet criteria for curative therapies-known as "downstaging" a patient to eligible tumor characteristics. More specific applications of radioembolization have been developed over the past two decades. Radioembolization may be employed to perform a radiation "lobectomy" in order to induce regression of the treated segments and hypertrophy of the untreated liver lobe such that the future liver remnant is sizeable enough to sustain life following resection. Similarly, the concept of radiation "segmentectomy"-involving the more selective administration of yttrium-90 microspheres with the intention of treating tumor and leading to the regression of the treated segment over time-has been proposed as a potential curative application of radioembolization. These radioembolization applications combine to augment the treatment options available to hepatocellular carcinoma patients both within and beyond transplantation criteria.

Background To compare image quality, lesion detection and patient comfort of 3T prostate MRI using a combined rigid two-channel phased-array endorectal coil and an external phased-array coil (ERC-PAC) compared to external PAC acquisition in the same patients. Methods Thirty three men (mean age 65.3y) with suspected (n = 15) or biopsy-proven prostate cancer (PCa, n = 18) were prospectively enrolled in this exploratory study. 3T prostate MRI including T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) was performed using an ERC-PAC versus PAC alone, in random order. Image quality, lesion detection and characterization (biparametric PI-RADSv2.1) were evaluated by 2 independent observers. Estimated signal-to-noise ratio (eSNR) was measured in identified lesions and the peripheral zone (PZ). Patient comfort was assessed using a questionnaire. Data were compared between sequences and acquisitions. Inter/intra-observer agreement for PI-RADS scores was evaluated. Results Twenty four prostate lesions (22 PCa) were identified in 20/33 men. Superior image quality was found for ERC-PAC compared to PAC for T2WI for one observer (Obs.1, p p p-values ≥0.08). Inter−/intra-observer agreement for PI-RADS scores was moderate-to-substantial (kappa = 0.52–0.84). Higher eSNR was observed for lesions and PZ for T2WI and PZ for DWI using ERC-PAC (p Conclusion Despite improved image quality and eSNR using the rigid ERC-PAC combination, no significant improvement in lesion detection was observed, therefore not supporting the routine use of ERC for prostate MRI.

As the 2019 novel coronavirus disease (COVID-19) continues to spread, some patients are presenting with abdominal symptoms without respiratory complaints. Our case series documents four patients who presented with abdominal symptoms whose abdominopelvic CT revealed incidental pulmonary parenchymal findings in the imaged lung bases and were subsequently confirmed positive for COVID-19 via laboratory testing. It remains to be seen whether these patients will eventually develop respiratory symptoms. While it is possible that the patients' abdominal complaints are coincidental with CT findings, it is interesting that patients can have such extensive incidental disease in the lungs on CT without respiratory symptoms., Highlights • Abdominal pain is being more recognized as a potential presenting for COVID-19. • Lung findings in COVID-19 patients may not correlate to respiratory symptoms. • Noting atypical presentation of COVID-19 allows for earlier quarantine and testing. • Early identification can further limit spread of COVID-19.

Type 2 endoleaks are a potential complication of endovascular aortic repair for abdominal aortic aneurysms. They are caused by vessels that have been excluded from the aorta lumen, but may still fill the aneurysm sac due to collateral filling. Type 2 endoleaks may lead to increased morbidity and need for additional procedures. Being able to identify patients at risk for Type 2 endoleaks and prevent them is important for any physician who is performing endovascular aortic repair.

Streamlining communication between radiology and referring services is vital to ensure appropriate care with minimal delays. Increased subspecialization has led to compartmentalization of the radiology department with many physicians working in disparate areas. At our hospital, we anecdotally noted that a significant portion of incoming phone calls were misdirected to the wrong workstations. This resulted in wasted time, unnecessary interruptions, and delays in care because the referring clinicians could not efficiently navigate the radiology department staffing structure. Our quality improvement project involved developing a web-based tool allowing the emergency department (ED) to more efficiently contact the appropriate radiology desk and reduce misdirected phone calls.Surveys were sent to radiology residents and ED providers (attendings, residents, physician assistants) to assess how often phone calls were misdirected to the wrong radiology station. Radiology residents were asked which stations received the most misdirected phone calls, and what station the caller was often looking for. ED providers were asked which stations they intended when they were told they called the wrong station, and a series of questions in the survey assessed their knowledge of commonly called radiology station (Plain Film, CT Body, Ultrasound, Neuoradiology, Pediatrics, and Overnight Desk). ED and radiology physicians worked together to design a simple, easily accessed web-based tool that allowed the ED clinicians to determine which station should be called during for each hour of the day, which integrated differences in staffing by radiology throughout the day. After the tool had been implemented for 8 months, surveys were again sent to radiology residents and ED clinicians asking the same questions as before to assess for any significant change in response. Additional questions were added to the ED survey to assess awareness of the new tool.An interactive, easily updated schedule with optimal contact numbers was made available through the ED intranet. The design allowed for easy modification of contact numbers over time to accommodate changes in coverage location or staffing models. Prior to implementation contact information was presented on a static screen, which was unable to be changed and included multiple incorrect and defunct numbers. Additionally, contact defaulted to a general radiology pager, which was carried by a resident only responsible for plain films for most of the day. Numbers included in the new intranet tool were all pertinent reading room stations, all scheduling desks, and all technologist workspaces. Different schedules were provided for weekdays and weekends. Initial survey results showed that prior to the intervention, 74% of radiology residents said they received misdirected phone calls at least twice a day, and 57.9% of ED respondents reached the wrong recipient at least once per day. Frequencies of misdirected calls dropped to 58.4% of radiology residents (P = 0.37) and 17.9% of ED respondents (P0.01) on follow-up surveys 8 months after the tool was established. After establishing the new tool, 82.1% of ED respondents were aware of the new intranet contact tool and were using it to contact radiology. On the series of questions assessing ED respondents' knowledge of radiology numbers, over 50% of respondents knew the correct answer or answered using the call sheet after implementation; this resulted in statistically significant increases in accuracy for Body, Neuroradiology, and Pediatric radiology stations. Furthermore, with the exception of ED plain films, there was a statistically significant reduction in number of responses who said the general radiology pager should be called for reads. Fifty percent of radiology residents believed there was a reduction in the number of misdirected phone calls from the ED with this tool.Our tool was successful in accomplishing multiple goals. First, over 80% of ED respondents adopted the new tool. Second, the number of misdirected phone calls based on the subjective perception of ED respondents and radiology residents was reduced. Third, we objectively improved the ED respondents' behavior pattern in contacting the radiology department by either calling the correct number using the call tool, and by reducing the number of respondents who use the pager. Going forward, we hope to be able to expand use of this tool throughout the hospital in order to provide more timely and efficient care with other services by streamlining access between referring services and the appropriate radiology recipients.

Surgery is the only curative therapy for carcinoid patients; however, many are unresectable due to direct involvement of the superior mesenteric artery (SMA) branches. In these patients, we sought to improve surgical outcomes via arterial skeletonization of the SMA prior to surgical resection. After left radial access, the SMA was catheterized, angiography was performed, and balloon occlusion was achieved in the tumor vessel. Following balloon occlusion of the affected artery, patients were assessed for symptoms of ischemia and angiographic evidence of distal perfusion via collaterals. If patients tolerated occlusion, an endovascular plug was deployed in the affected artery; if not, the procedure was terminated. The next day, all patients underwent exploratory laparotomy and surgical resection of tumor and bowel. The procedure was performed 15 times on 14 patients. 13 out of 15 procedures went to embolization, while the other 2 proceeded to surgery without plug deployment. One of the embolized patients had serious post-surgical complications, while both non-embolized patients developed complications including short bowel syndrome and ischemic colitis. Length of stay between embolized and non-embolized patients was equal, but re-admittance within 30 days was 7.7% in the embolized group and 100% in the non-embolized group. Our initial experience demonstrates feasibility and safety of deploying plugs within branches of the SMA prior to surgical resection and improved surgical outcomes. Palpation of the plug assisted in surgical resection. We have demonstrated that pre-operative endovascular occlusion is a safe, practical procedure, which aids surgical resection of mesenteric carcinoid disease.

Aorto-atrial fistulas are a rare diagnosis with limited reports in the clinical literature. These findings are often characterized by echocardiography alone; however, the advent and increased availability and use of CT angiography to diagnose cardiac abnormalities provides improved anatomic visibility of potential defects. We are reporting a case of a 76-year-old male with decompensated heart failure secondary to a fistula between the aorta and left atrium after remote history of bioprosthetic aortic valve replacement.

This review focuses on the usefulness of inferior vena cava (IVC) filters in the setting of trauma by examining the scientific literature on this specific use for IVC filters, as well as in other situations that can be extrapolated to the trauma setting. Recent research overall has indicated that IVC filters are not as benign as they were once thought to be, and that use of them should be more carefully considered given the risks associated with the device. With regards to using IVC filters in trauma, recently published meta-analysis conclude that the data is inconclusive for using IVC filters in the setting of trauma. New devices such as the Angel catheter may help alleviate the risks associated with IVC filter use. Further data being collected by the ongoing Predicting the Safety and Effectiveness of Inferior Vena Cava Filters (PRESERVE) trial will assist in improving the scientific understanding of the benefits and risks to IVC filters. Overall, the literature supporting the use of IVC filters in trauma patients is limited; however, there seems to be slight evidence which suggests that these devices are likely beneficial in patients who cannot receive anticoagulation for DVT prophylaxis, but fall into a high-risk trauma category (severe brain or spine injury, long bone injury, or the elderly).

“Just Accepted” papers have undergone full peer review and have been accepted for publication in Radiology: Artificial Intelligence. This article will undergo copyediting, layout, and proof review before it is published in its final version. Please note that during production of the final copyedited article, errors may be discovered which could affect the content. Purpose To train a deep learning classification algorithm to predict chest radiography severity scores and clinical outcomes in patients with coronavirus disease 2019 (COVID-19). Materials and Methods In this retrospective cohort study, we identified patients of ages of 21 to 50 who presented to the emergency department (ED) of a multicenter urban health system from March 10–26, 2020 with COVID-19 confirmation on real-time reverse transcription polymerase chain reaction. We collected the initial chest radiographs (CXRs), clinical variables, and outcomes including admission, intubation, and survival within 30 days (n = 338; median age 39; 210 men). Two fellowship-trained cardiothoracic radiologists examined CXRs for opacities and assigned a clinically validated severity score. We trained a deep learning algorithm to predict outcomes on a holdout test set composed of confirmed COVID-19 patients who presented from March 27–29, 2020 (n = 161; median age 60; 98 men) for both younger (ages 21–50; n = 51) and older (ages > 50; n = 110) populations. Bootstrapping methods computed confidence intervals. Results The model trained on the CXR severity score produced the following areas under the receiver operating characteristic (AUCs): 0.80 (0.73,0.88) for the CXR severity score, 0.76 (0.68,0.84) for admission, 0.66 (0.56,0.75) for intubation, and 0.59 (0.49,0.69) for death. The model trained on clinical variables produced the following AUCs 0.64 (0.55,0.73) for intubation and 0.59 (0.50,0.68) for death. Combining CXR and clinical variables increased AUC of intubation and death to 0.86 (0.79,0.96) and 0.82 (0.72,0.91), respectively. Conclusion The combination of imaging and clinical information improves outcome predictions.

In this article we will review the imaging features of COVID-19 across multiple modalities, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography/computed tomography (PET/CT), and ultrasonography (US). Given that COVID-19 primarily affects the lung parenchyma by causing pneumonia, our directive is to focus on thoracic findings associated with COVID-19. We aim to enhance radiologists’ understanding of this disease in order to help guide diagnosis and management.

Pancreas transplants are an important treatment options for patients with severe diabetes mellitus and other medical conditions. Multiple-imaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US) are available to evaluate the pancreas transplants and their vascular supply, with the graft having a characteristic appearance on each modality. Complications of the graft and its vascular supply present interesting challenges to the clinicians and radiologists caring for this patient population. Being able to identify the imaging appearance of normal and abnormal pancreas transplants, it is necessary to ensure these patients are provided optimal care.

90Y radioembolization is an increasingly used treatment for both primary and metastatic malignancy in the liver. Understanding the biophysical properties, dosing concerns, and imaging appearance of this treatment is important for interventional radiologists and nuclear medicine physicians to provide important therapy. 90Y radioembolization is efficacious and safe, although the possibility of complications does exist. This article provides a comprehensive in-depth discussion about the indications for 90Y radioembolization, reviews the role of preprocedural angiography and 99mTc-macroaggregated albumin scans, illustrates different dosing techniques, compares and contrasts resin and glass microspheres, and describes potential complications.

Hyperglycemia has been shown to influence fluorine-18 fluorodeoxyglucose ((18)F-FDG) uptake in tumor cells. Therefore, patients are instructed to fast for 6 h, while maintaining serum glucose levels at an acceptable range. The study was performed to evaluate the effect of fasting blood glucose levels on the biodistribution of (18)F-FDG in various tissues including the liver, heart, bone marrow, skeletal muscle, and tumors.Fingerstick fasting blood glucose is routinely measured on the morning of the procedure. The maximum standardized uptake value (SUV(max)) in the right and left hepatic lobes, left ventricle, sacrum, thigh, and tumor was measured in 229 consecutive patients undergoing (18)F-FDG PET/computed tomography for tumor. Patients were divided into three groups depending on their serum glucose levels: low (100; n = 53), medium (100-160; n = 149), and high (160-201; n = 27). A retrospective analysis of the relationship between glucose levels and standardized uptake value was performed.There was a statistically significant increase in the average SUV(max) in the right and left hepatic lobes as glucose levels increased (right lobe P=0.00144; left lobe P = 0.03889). Subsequently, pairwise analysis was performed, revealing a statistically significant increase in SUV(max) in the right hepatic lobe between low-glucose and medium-glucose groups and in both hepatic lobes between low and high groups (P0.017). No significant difference was observed in any of the other measured tissues.This study shows a directly proportional relationship between blood glucose levels and nonpathologic (18)F-FDG biodistribution in the right and left hepatic lobes. The influence of blood glucose on expected biodistribution patterns, particularly in the liver, should be considered during interpretation.

Recent EEG studies have shown that implicit learning involving specific cortical circuits results in an enduring local trace manifested as local changes in spectral power. Here we used a well characterized visual sequence learning task and high density-(hd-)EEG recording to determine whether also declarative learning leaves a post-task, local change in the resting state oscillatory activity in the areas involved in the learning process. Thus, we recorded hd-EEG in normal subjects before, during and after the acquisition of the order of a fixed spatial target sequence (VSEQ) and during the presentation of targets in random order (VRAN). We first determined the temporal evolution of spectral changes during VSEQ and compared it to VRAN. We found significant differences in the alpha and theta bands in three main scalp regions, a right occipito-parietal (ROP), an anterior-frontal (AFr), and a right frontal (RFr) area. The changes in frontal theta power during VSEQ were positively correlated with the learning rate. Further, post-learning EEG recordings during resting state revealed a significant increase in alpha power in ROP relative to a pre-learning baseline. We conclude that declarative learning is associated with alpha and theta changes in frontal and posterior regions that occur during the task, and with an increase of alpha power in the occipito-parietal region after the task. These post-task changes may represent a trace of learning and a hallmark of use-dependent plasticity.