Parameters for estimating the feasibility of implantation of a semi-implantable bone conduction device (SIBCD) in children and adolescents.

PURPOSE: In children and adolescents, preoperative planning for a semi-implantable bone conduction device (SIBCD) is crucial. The geometric changes of the new version of a common SIBCD should enable a higher rate of successful implantation due to its flatter actuator. Thus, this radioanatomic study compared the rate of successful implantation of both device versions at the traditional mastoidal localization and two alternative sites, retrosigmoidal, and parietal, and investigated parameters helping to estimate the feasibility. METHODS: A retrospective analysis of 136 CT scans of 0 to 20-year-old patients, evaluation of demographic parameters, radioanatomy, and assessment of head diameter was conducted. The feasibility was investigated for certain age groups at three implantation sites. Prediction of feasible implantation by means of different parameters was calculated. RESULTS: A significant higher implantation rate was observed with the new device for all three sites and age groups. The age group of 6-8 years (n = 19) had most striking differences with a 58.1% rate of successful implantation with the new device without spacer (80% with spacer) at the mastoidal localization, whereas none with the old implant. Head diameter was identified as the most predictive parameter regarding all implantation sites (mastoidal: p = 0.030; retrosigmoidal: p = 0.006; parietal: p < 0.0001), age for the mastoidal (p < 0.0001) and retrosigmoidal (p < 0.0001), and gender for the parietal site (p = 0.001). CONCLUSION: The geometric changes of the actuator lead to a higher rate of successful implantation in all age-groups and all three localizations with reducing the requirement for spacers. Parameters age and head diameter might aid in estimating the rate of successful implantation in young patients and may be a novel tool to assist in the decision-making process for a SIBCD.

From the Bottlecap to the Bottleneck: Frequent Esophageal Impaction of Bottlecaps Among Young Males in a Small University Town.

There have been few reports of ingestion of bottlecaps worldwide. However, all of these seemed to be unlikely accidental ingestions with a comic side effect. In contrast to this, the authors of this study found an accumulation of bottlecap ingestions in a small university town. Hence, we conducted a study to investigate the nature of these ingestions. We conducted a retrospective cohort study in a tertiary referral center in a small German university town (Göttingen). All patients that were admitted for esophageal foreign bodies were screened for accidental ingestion of bottlecaps and included in the study at hand. Overall, there were 14 cases of bottlecap ingestion within 12 years. Patients were exclusively male, average age was 23.0 ± 4.2 years, ranging from 18.3 to 35.6 years. In 13 out of 14 cases, association to a fraternity was found. Young men, particularly those belonging to a fraternity, should be beware of bottlecap ingestion when consuming beer in risky rituals in small university towns. Alternatively, competitive beer drinking may generally be avoided.

Influence of short-term dexamethasone on the efficacy of 177 Lu-PSMA-617 in patients with metastatic castration-resistant prostate cancer.

BACKGROUND AND AIM: Corticosteroids alone or in combination therapy are associated with favorable biochemical responses in metastatic castration-resistant prostate cancer (mCRPC). We speculated that the intermittent addition of dexamethasone may also enhance the antitumor effect of radioligand therapy (RLT) with 177 Lu-prostate-specific membrane antigen (PSMA)-617. PATIENTS AND METHODS: Seventy-one patients with mCRPC were treated with 1 to 5 cycles of 177 Lu-PSMA-617 (6.0-7.4 GBq per cycle) at 6 to 8 weeks intervals. Based on the clinical decision (eg, in the case of vertebral metastases), 56% of patients received 4 mg of dexamethasone for the first 5 days of each cycle. Biochemical response rates, PSA decline and progression-free survival (PFS) were analyzed after one, three, and five cycles of RLT. RESULTS: PSA response rates were not significantly different between patients receiving 177 Lu-PSMA-617 plus dexamethasone and those receiving 177 Lu-PSMA-617 alone after one, three, and five cycles (33% vs 39%, P = .62; 45% vs 45%, P = 1.0; and 38% vs 42%, P = .81). However, there was a nonsignificant trend for a more pronounced PSA decline in patients with bone metastases receiving adjunct dexamethasone (-21% ± 50% vs +11% ± 90%, P = .08; -21% ± 69% vs +22% ± 116%, P = .07; -13% ± 76% vs +32% ± 119%, P = .07). Median PFS tended to be longer in patients with bone metastases receiving 177 Lu-PSMA-617 plus dexamethasone (146 vs 81 days; hazard ratio: 0.87 [95% confidence interval: 0.47-1.61]; P = .20). Multiple regression analysis showed that age (P = .0110), alkaline phosphatase levels (P = .0380) and adjunct dexamethasone (P = .0285) were independent predictors of changes in PSA in patients with bone metastases. CONCLUSIONS: We observed high response rates to 177 Lu-PSMA-617 RLT in men with mCRPC. The short-term addition of dexamethasone to 177 Lu-PSMA-617 had no striking antitumor effect but might enhance biochemical responses in patients with bone metastases. Future trials are warranted to test this hypothesis in a prospective setting.

Neuroendocrine Differentiation and Response to PSMA-Targeted Radioligand Therapy in Advanced Metastatic Castration-Resistant Prostate Cancer: A Single-Center Retrospective Study.

Neuroendocrine differentiation is associated with treatment failure and poor outcome in metastatic castration-resistant prostate cancer. We investigated the effect of circulating neuroendocrine biomarkers on the efficacy of prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT). Methods: Neuroendocrine biomarker profiles (progastrin-releasing peptide, neuron-specific enolase, and chromogranin-A) were analyzed in 50 patients commencing 177Lu-PSMA-617 RLT. The primary endpoint was a prostate-specific antigen response in relation to baseline neuroendocrine marker profiles. An additional endpoint was progression-free survival. Tumor uptake on posttherapeutic scans, a known predictive marker for response, was used as a control variable. Results: Neuroendocrine biomarker profiles were abnormal in most patients. Neuroendocrine biomarker levels did not predict treatment failure or early progression (P ≥ 0.13). By contrast, intense PSMA-ligand uptake in metastases predicted both treatment response (P = 0.0030) and reduced risk of early progression (P = 0.0111). Conclusion: Neuroendocrine marker profiles do not predict an adverse outcome from RLT. By contrast, high ligand uptake was confirmed to be crucial for achieving a tumor response.

18F-FDG PET/CT in Left-Ventricular Assist Device Infection: Initial Results Supporting the Usefulness of Image-Guided Therapy.

Accurate definition of the extent and severity of left-ventricular assist device (LVAD) infection may facilitate therapeutic decision making and targeted surgical intervention. Here, we explore the value of 18F-FDG PET/CT for guidance of patient management. Methods: Fifty-seven LVAD-carrying patients received 85 whole-body 18F-FDG PET/CT scans for the work-up of device infection. Clinical follow-up was obtained for up to 2 y. Results: PET/CT showed various patterns of infectious involvement of the 4 LVAD components: driveline entry point (77% of patients), subcutaneous driveline path (87%), pump pocket (49%), and outflow tract (58%). Driveline smears revealed Staphylococcus or Pseudomonas strains as the underlying pathogen in most cases (48 and 34%, respectively). At receiver-operating-characteristic analysis, an 18F-FDG SUV of more than 2.5 was most accurate to identify smear-positive driveline infection. Infection of 3 or all 4 LVAD components showed a trend toward lower survival than did infection of 2 or fewer components (P = 0.089), whereas involvement of thoracic lymph nodes was significantly associated with an adverse outcome (P = 0.001 for nodal SUV above vs. below median). Finally, patients who underwent early surgical revision within 3 mo after PET/CT (n = 21) required significantly less inpatient hospital care during follow-up than did those receiving delayed surgical revision (n = 11; P < 0.05). Conclusion: Whole-body 18F-FDG PET/CT identifies the extent of LVAD infection and predicts adverse outcome. Initial experience suggests that early image-guided surgical intervention may facilitate a less complicated subsequent course.

Incidental findings on craniomaxillofacial cone beam computed tomography in orthodontic patients.

PURPOSE: Cone beam computed tomography (CBCT) in orthodontics is increasingly used for detecting impacted or ectopic teeth or for orthognathic and cleft lip and palate treatment. Incidental findings (IFs) are frequently encountered and often relevant. The aim of this study was to detect the prevalence of relevant pathologies on CBCT scans of orthodontic patients. METHODS: Over a 6-year period, incidental imaging findings were analyzed in 345 CBCT scans (181 men; 164 women; age 16.3 ± 8.4 years), and subdivided into dental (Group 1), skeletal (Group 2), sinunasal (Group 3), and infrequent other pathologies (Group 4). RESULTS: A total of 502 IFs were detected in 345 patients (1.4 IFs per patient, on average). Most IFs were found in Group 1 (358 IFs; 71.3%), followed by Group 2 (129 IFs; 25.7%), Group 3 (14 IFs; 2.8%), and Group 4 (1 IF; 0.2%). There were 119 (34.5%) patients with a missing wisdom tooth, 94 (27.3%) with dental aplasia, 71 (20.6%) with dislocations, 33 (9.6%) with partial opacifications, and 27 (7.8%) with signs of sinusitis. CONCLUSIONS: This study found that IFs in orthodontic CBCT scans are frequently encountered, even in younger orthodontic patients. When interpreting CBCT scans, orthodontists should be aware of potential relevant IFs that may require further investigation, change patients' treatment or affect their quality of life.

Screening of extravascular findings in pulmonary embolism computer tomography: 397 patients with 1950 non-pulmonary artery findings.

Objectives The aim of this study was to investigate the possible benefits from computed tomography scans of patients with a suspected pulmonary artery embolism with a focus on relevant extravascular findings. Methods A total of 400 consecutive computed tomography pulmonary angiographies were evaluated. Computed tomography scans were analyzed in detail for the presence of pulmonary artery embolisms, as well as any other findings. Extra-artery discoveries were classified into none-relevant (Group A), intermediate (Group B), or relevant (Group C) findings. Results Aggregated computed tomography pulmonary angiographies detected other diagnosis than pulmonary artery embolism in 236 patients (59%). There were 1950 non-pulmonary artery embolism findings (4.9 per patient; n = 397). In the pulmonary artery embolism group, there were 447 extra-pulmonary artery embolism findings (5.2 per patient; n = 86) and in the non-pulmonary artery embolism group, 1503 findings (4.8 per patient; n = 311). Patients with pulmonary artery embolism had a significantly higher rate of pro-coagulate risk factors ( p < 0.001). Conclusions Computed tomography pulmonary angiographies may help to identify further diagnoses. This study represents a retrospective review of a single center experience for incidental computed tomography findings during pulmonary artery embolism work-up and emphasizes the importance of analyzing the whole field-of-view.

Clinical Molecular Imaging of Chemokine Receptor CXCR4 Expression in Atherosclerotic Plaque Using 68Ga-Pentixafor PET: Correlation with Cardiovascular Risk Factors and Calcified Plaque Burden.

The CXC-motif chemokine receptor 4 (CXCR4) represents a promising target for molecular imaging of different CXCR4-positive cell types in cardiovascular diseases such as atherosclerosis and arterial wall injury. The aim of this study was to assess the prevalence, pattern, and clinical correlates of arterial wall accumulation of 68Ga-pentixafor, a specific CXCR4 ligand for PET. Methods: The data for 51 patients who underwent 68Ga-pentixafor PET/CT for noncardiovascular indications were retrospectively analyzed. Tracer accumulation in the vessel wall of major arteries was analyzed qualitatively and semiquantitatively by blood-pool-corrected target-to-background ratios. Tracer uptake was compared with calcified plaque burden and cardiovascular risk factors. Results: Focal arterial uptake of 68Ga-pentixafor was seen at 1,411 sites in 51 (100%) of patients. 68Ga-pentixafor uptake was significantly associated with calcified plaque burden (P < 0.0001) and cardiovascular risk factors including age (P < 0.0001), arterial hypertension (P < 0.0001), hypercholesterolemia (P = 0.0005), history of smoking (P = 0.01), and prior cardiovascular events (P = 0.0004). Both the prevalence (P < 0.0001) and the signal intensity (P = 0.009) of 68Ga-pentixafor uptake increased as the number of risk factors increased. Conclusion:68Ga-pentixafor PET/CT is suitable for noninvasive, highly specific PET imaging of CXCR4 expression in the atherosclerotic arterial wall. Arterial wall 68Ga-pentixafor uptake is significantly associated with surrogate markers of atherosclerosis and is linked to the presence of cardiovascular risk factors. 68Ga-pentixafor signal is higher in patients with a high-risk profile and may hold promise for identification of vulnerable plaque.

Absence of DNA double-strand breaks in human peripheral blood mononuclear cells after 3 Tesla magnetic resonance imaging assessed by γH2AX flow cytometry.

OBJECTIVES: Magnetic resonance imaging (MRI) is regarded as a non-harming and non-invasive imaging modality with high tissue contrast and almost no side effects. Compared to other cross-sectional imaging modalities, MRI does not use ionising radiation. Recently, however, strong magnetic fields as applied in clinical MRI scanners have been suspected to induce DNA double-strand breaks in human lymphocytes. METHODS: In this study we investigated the impact of 3-T cardiac MRI examinations on the induction of DNA double-strand breaks in peripheral mononuclear cells by γH2AX staining and flow cytometry analysis. The study cohort consisted of 73 healthy non-smoking volunteers with 36 volunteers undergoing CMRI and 37 controls without intervention. Differences between the two cohorts were analysed by a mixed linear model with repeated measures. RESULTS: Both cohorts showed a significant increase in the γH2AX signal from baseline to post-procedure of 6.7 % (SD 7.18 %) and 7.8 % (SD 6.61 %), respectively. However, the difference between the two groups was not significant. CONCLUSION: Based on our study, γH2AX flow cytometry shows no evidence that 3-T MRI examinations as used in cardiac scans impair DNA integrity in peripheral mononuclear cells. KEY POINTS: • No evidence for DNA double-strand breaks after cardiac MRI. • Prospective study underlines safe use of MRI with regard to DNA damage. • Controlled trial involving both genders investigating DNA DSBs after 3-T MRI.

Extra-vascular findings in patients undergoing magnetic resonance angiography of the abdomen, pelvis and lower extremities: A retrospective study of 352 patients.

Background The aim of this study was to assess the prevalence and clinical significance of extra-vascular findings in patients undergoing magnetic resonance angiography of the abdomen, pelvis and lower extremities. Materials and methods Three hundred fifty-two patients underwent abdominal, pelvic and lower extremity 1.5 T magnetic resonance angiography. Clinically relevant vascular and extra-vascular findings were identified. Relevant vascular findings were classified as stenosis, occlusion, aneurysm, sclerosis, dissection or vasculitis. Relevant extra-vascular findings were categorized as 'safe' (Group A), intermediate - requiring additional investigation - (Group B) and malignant/endangering - requiring change of therapy (Group C). Results A total of 2152 clinically relevant vascular findings was identified (6.1/patient). The most frequent vascular finding was femoral artery stenosis (10.6%). Four hundred fifty-one extra-vascular findings were observed (1.3/patient) and classified into Group A (78%), Group B (19.5%) and Group C findings (2.4%). The most frequent malignant findings were lung cancer, lymphoma, osteosarcoma, hepatocellular carcinoma and renal cell carcinoma (7/352 patients). Conclusions Extravascular findings are frequently encountered in magnetic resonance angiography performed for vascular indications. Clinically relevant findings are seen in a substantial part of patients and should prompt further diagnostic work-up.

Targeting Cardiovascular Implant Infection: Multimodality and Molecular Imaging.

Owing to their success in clinical practice, the prevalence of cardiovascular implants is continuously increasing. Implant infection is a relevant complication but remains a diagnostic challenge because echocardiography as a first-line test may be limited. Accordingly, a multimodality approach is increasingly used for diagnostic workup and supported by recent guidelines. As reviewed here, computed tomography and nuclear imaging provide incremental diagnostic value and may be combined in a single hybrid imaging session using positron emission tomography/computed tomography or single photon emission computed tomography/computed tomography. Molecular or cellular imaging helps to overcome the limitations of morphological imaging in implants. Larger-scale clinical studies, earlier application in the time course of diagnosis, monitoring of therapy success, technical advances, and novel radiopharmaceuticals will all contribute to sustained growth of advanced infection-targeted imaging in cardiovascular medicine.

Initial Experience with Volumetric 68Ga-PSMA I&T PET/CT for Assessment of Whole-Body Tumor Burden as a Quantitative Imaging Biomarker in Patients with Prostate Cancer.

A quantitative imaging biomarker is desirable to provide a comprehensive measure of whole-body tumor burden in patients with metastatic prostate cancer, and to standardize the evaluation of treatment-related changes. Therefore, we evaluated whether prostate-specific membrane antigen (PSMA) ligand PET/CT may be applied to provide PSMA-derived volumetric parameters for quantification of whole-body tumor burden. Methods: One hundred one patients who underwent 68Ga-PSMA I&T PET/CT because of increasing prostate-specific antigen (PSA) levels after radical prostatectomy were included in this retrospective analysis. Tracer uptake was quantified using SUVs. Volumetric parameters, that is, PSMA-derived tumor volume (PSMA-TV) and total lesion PSMA (TL-PSMA), were calculated for each patient using a 3-dimensional segmentation and computerized volumetry technique and compared with serum PSA levels. In a group of 10 patients, volumetric parameters were applied for treatment monitoring. Results: Volumetric parameters, that is, whole-body PSMA-TV and whole-body TL-PSMA, demonstrated a statistically significant correlation with PSA levels (P < 0.0001) as a surrogate marker of tumor burden, whereas SUVmax (P = 0.22) or SUVmean (P = 0.45) did not. Treatment response and treatment failure were paralleled by concordant changes in both whole-body PSMA-TV and whole-body TL-PSMA (P = 0.02), whereas neither the change in SUVmax (P = 1.0) nor the change in SUVmean (P = 1.0) concordantly paralleled changes in PSA levels. Conclusion: PSMA-derived volumetric parameters provide a quantitative imaging biomarker for whole-body tumor burden, capable of standardizing quantitative changes in PET imaging of patients with metastatic prostate cancer and of facilitating therapy monitoring.

Systematic radiographic evaluation of three potential implantation sites for a semi-implantable bone conduction device in 52 patients after previous mastoid surgery.

The aim of this study was the evaluation of three localizations for the implantation of a semi-implantable transcutaneous bone conduction device after previous mastoid surgery. This is a retrospective review of electronic datasets of cranial computed tomography studies. The study setting is one tertiary referral center and included 52 consecutive adult patients (60 temporal bones) with a history of mastoid surgery. The intervention was virtual placement of the device with a planning software within the remaining mastoid as well as dorsal of the sigmoid sinus and caudal of the transverse sinus (retrosigmoidal localization) and dorsocranial of the parietomastoid suture and cranial of the transverse sinus (parietal localization). The main outcome measure included dimensions of the bone for the reception of implant and screws, relative localization of dura mater or sinus sigmoideus, distance to the cochlea, thickness of the epicranium and classification of implantation as possible or impossible. Implantation within the remaining mastoid was deemed possible in 35 mastoid bones (58.3%). The best-suited alternative localization was retrosigmoidal in 22 (42.3%) and parietal in 29 patients (55.8%). The mean distance from the implantation site to the cochlea was lowest with on average 41.2 ± 3.1 mm from within the remaining mastoid. The differences in distance from the cochlea to the alternative localizations were each statistically significant (p < 0.01, ANOVA/Bonferroni t test). The retrosigmoidal and parietal localizations are suitable alternative implantation sites. The application of spacers may prevent contact to the sinuses or dura. Preoperative CT-based planning is recommended in cases of previous mastoid surgery. LEVEL OF EVIDENCE: 4 (case series).

Incidental findings in cardiac magnetic resonance imaging: superiority of bSSFP over T1w-HASTE for extra-cardiac findings assessment.

Incidental findings are frequent in radiological examinations and may have an impact on further patient management. The aim of this retrospective study was to analyze, which of two thoracic scout sequences is more suitable for detecting incidental extra-cardiac findings at cardiac magnetic resonance imaging (CMRI) with stress perfusion. During a 14-month period clinically indicated stress perfusion CMRI was performed in 97 consecutive patients. For anatomical orientation ECG-triggered (electrocardiography) T1w-Half-fourier acquisition single-shot turbo spin-echo (HASTE) and balanced steady state free precession (bSSFP) sequences were performed for planning the standard cardiac sequences. Two radiologists independently studied incidental extra-cardiac findings with both sequences and rated the diagnostic confidence of the sequences for this assessment using a multinomial model. Furthermore, the interobserver agreement between the observers was assessed by weighted kappa statistics. Eight patients without incidental findings were excluded. In the other 89 patients a total of 153 incidental extra-cardiac findings were observed. Overall, 47.1% of findings were seen with better diagnostic confidence at bSSFP as opposed to 20.6% at T1w-HASTE. 32.4% of findings were equally well seen with both sequences. Consequently the bSSFP sequence was significantly better in terms of diagnostic confidence for detecting the majority of extra-cardiac incidental findings (P < 0.01), whereas a minority of findings was better visible by the HASTE sequence. The weighted kappa statistics was 0.85, indicating good interobserver agreement. Compared with T1w-HASTE, the bSSFP sequence improved the visibility of incidental extra-cardiac findings at stress perfusion CMRI. While all findings were seen on both sequences, bSSFP resulted in improved diagnostic confidence, and the T1w-HASTE sequence provided complementary diagnostic information in only a minority of patients.

Comparison of standard and delayed imaging to improve the detection rate of [68Ga]PSMA I&T PET/CT in patients with biochemical recurrence or prostate-specific antigen persistence after primary therapy for prostate cancer.

PURPOSE: The aim of this study was to assess the value of dual-time point imaging in PET/CT for detection of biochemically recurrent or persistent prostate cancer, using the prostate-specific membrane antigen (PSMA) ligand [68Ga]PSMA I&T. METHODS: 240 patients who underwent a [68Ga]PSMA I&T PET/CT in the context of biochemical relapse of prostate cancer were included in this retrospective analysis. Imaging consisted of a standard whole-body PET/CT (1 h p.i.), followed by delayed (3 h p.i.) imaging of the abdomen. PSA-stratified proportions of positive PET/CT results, standardized uptake values and target-to-background ratios were analyzed, and compared between standard and delayed imaging. RESULTS: The overall detection rates of [68Ga]PSMA I&T PET/CT were 94.2, 71.8, 58.6, 55.9 and 38.9% for PSA levels of ≥2, 1 to <2, 0.5 to <1, >0.2 to <0.5, and 0.01 to 0.2 ng/mL, respectively. Although the target-to-background ratio improved significantly over time (P < 0.0001), the majority (96.6%) of all lesions suggestive of recurrent disease could already be detected in standard imaging. Delayed imaging at 3 h p.i. exclusively identified pathologic findings in 5.4% (10/184) of abnormal [68Ga]PSMA I&T PET/CT scans, and exclusively detected 3.4% (38/1134) of all lesions suggestive of recurrent disease. CONCLUSIONS: [68Ga]PSMA I&T PET/CT shows high detection rates in patients with prostate-specific antigen persistence or biochemical recurrence of prostate cancer. Delayed imaging can detect lesions with improved contrast compared to standard imaging. However, the impact on detection rates was limited in this study.

Multiple Time-Point 68Ga-PSMA I&T PET/CT for Characterization of Primary Prostate Cancer: Value of Early Dynamic and Delayed Imaging.

PURPOSE: The aims of this study were to gain mechanistic insights into prostate cancer biology using dynamic imaging and to evaluate the usefulness of multiple time-point Ga-prostate-specific membrane antigen (PSMA) I&T PET/CT for the assessment of primary prostate cancer before prostatectomy. METHODS: Twenty patients with prostate cancer underwent Ga-PSMA I&T PET/CT before prostatectomy. The PET protocol consisted of early dynamic pelvic imaging, followed by static scans at 60 and 180 minutes postinjection (p.i.). SUVs, time-activity curves, quantitative analysis based on a 2-tissue compartment model, Patlak analysis, histopathology, and Gleason grading were compared between prostate cancer and benign prostate gland. RESULTS: Primary tumors were identified on both early dynamic and delayed imaging in 95% of patients. Tracer uptake was significantly higher in prostate cancer compared with benign prostate tissue at any time point (P ≤ 0.0003) and increased over time. Consequently, the tumor-to-nontumor ratio within the prostate gland improved over time (2.8 at 10 minutes vs 17.1 at 180 minutes p.i.). Tracer uptake at both 60 and 180 minutes p.i. was significantly higher in patients with higher Gleason scores (P < 0.01). The influx rate (Ki) was higher in prostate cancer than in reference prostate gland (0.055 [r = 0.998] vs 0.017 [r = 0.996]). CONCLUSIONS: Primary prostate cancer is readily identified on early dynamic and static delayed Ga-PSMA ligand PET images. The tumor-to-nontumor ratio in the prostate gland improves over time, supporting a role of delayed imaging for optimal visualization of prostate cancer.

68Ga-DOTA-TATE PET/CT for Molecular Imaging of Somatostatin Receptor Expression in Metastasizing Chordoma: Comparison With 18F-FDG.

Chordoma is a rare slow-growing neoplasm of neuroectodermal origin, which frequently recurs after removal and has the potential to metastasize. We present the case of a 53-year-old man with metastasizing chordoma who underwent F-FDG and Ga-DOTA-TATE PET/CT for restaging of disease and for evaluation of targeted radionuclide therapy potential. On both F-FDG and Ga-DOTA-TATE PET scans, increased tracer accumulation was observed in chordoma metastases. Besides the increased glucose metabolism in chordoma, this case highlights the potential of Ga-DOTA-TATE PET/CT for restaging of chordoma as well the option of targeted radionuclide therapy in this entity.

Multitracer Molecular Imaging of Paget Disease Targeting Bone Remodeling, Fatty Acid Metabolism, and PSMA Expression on PET/CT.

Paget disease is a chronic disorder resulting in enlarged and misshapen bones, and is caused by disorganized bone remodeling. We present the case of an 85-year-old man with prostatic adenocarcinoma and known Paget disease of the right iliac bone who underwent Ga-prostate-specific membrane antigen ligand, C-acetate, and F-fluoride PET/CT for restaging of cancer. On all PET scans, increased tracer accumulation was observed in Paget disease of bone. Besides that Paget disease may mimic metastases on PET/CT using various radiotracers, including Ga-prostate-specific membrane antigen ligands and C-acetate, this case highlights the potential of multiparametric disease characterization on PET.

Peak flow velocities in the ascending aorta-real-time phase-contrast magnetic resonance imaging vs. cine magnetic resonance imaging and echocardiography.

This prospective study of eight healthy volunteers evaluates peak flow velocities (PFV) in the ascending aorta using real-time phase-contrast magnetic resonance imaging (MRI) in comparison to cine phase-contrast MRI and echocardiography. Flow measurements by echocardiography and cine phase-contrast MRI with breath-holding were performed according to clinical standards. Real-time phase-contrast MRI at 40 ms temporal resolution and 1.3 mm in-plane resolution was based on highly undersampled radial fast low-angle shot (FLASH) sequences with image reconstruction by regularized nonlinear inversion (NLINV). Evaluations focused on the determination of PFV. Linear regressions and Bland-Altman plots were used for comparisons of methods. When averaged across subjects, real-time phase-contrast MRI resulted in PFV of 120±20 cm s(-1) (mean ± SD) in comparison to 122±16 cm s(-1) for cine MRI and 124±20 cm s(-1) for echocardiography. The maximum deviations between real-time phase-contrast MRI and echocardiography ranged from -20 to +14 cm s(-1) (cine MRI: -10 to +12 cm s(-1)). Thus, in general, real-time phase-contrast MRI of cardiac outflow revealed quantitative agreement with cine MRI and echocardiography. The advantages of real-time MRI are measurements during free breathing and access to individual cardiac cycles.

Right Atrial Volume is Increased in Corrected Tetralogy of Fallot and Correlates with the Incidence of Supraventricular Arrhythmia: A CMR Study.

The aim of this study was to evaluate right atrial (RA) volume in corrected Tetralogy of Fallot (cTOF) and assess its correlation with the occurrence of supraventricular (SV) arrhythmia. Cardiac magnetic resonance imaging (CMR) and 24-h Holter were performed in n = 67 consecutive cTOF patients (age 30 ± 11.3 years). The CMR protocol included standard HASTE, SSFP cine, and blood flow measurements. Correlations between arrhythmia in ECG, heart volume, and functional parameters were investigated by negative binominal regression. Patients' characteristics (mean ± SD) included mean RA volume of 49 ± 19 ml/m(2) (HASTE sequence), mean right ventricular (RV) end-diastolic volume of 98 ± 27 ml/m(2), mean pulmonary valve regurgitation fraction (PR) of 21 ± 19 %, BMI of 25 kg/m(2), and heart rate of 75/min. Twenty-eight out of 67 patients experienced SV arrhythmia including SV couplets or bigeminus or longer non-sustained SV tachycardia (SVT) episodes. RA volume index was identified as an independent risk factor for different degrees of SV arrhythmia (SV couplets/bigeminus p < 0.001, SVT p < 0.001). Further risk factors for SV arrhythmia were male gender (p = 0.023) and decreased left ventricular (LV) ejection fraction (EF) (LV EF p < 0.001). RA volume is increased in adult patients with cTOF with larger RA volumes relating to higher incidence of SV arrhythmia. SV arrhythmia also appeared more often in male patients and those with decreased LV EF. Risk stratification according to these parameters could help to optimize early prevention and adjusted individual therapy to improve patient outcome and quality of life.