Purpose: To evaluate the impact of video sequences (cine-loops) on the interobserver agreement (IOA) using risk stratification systems (RSSs) for thyroid nodules (TNs). Methods: Twenty TNs were randomly selected from a large database and evaluated by twelve experienced observers using five different RSSs (Kwak-, ACR-, EU-, Korean-TIRADS, ATA Guidelines). In the first step, the evaluation was conducted based on static ultrasound (US) images in two planes (“static”). Six months later, these cases were reevaluated by the same observers using video sequences in two planes (“cine-loops”). Fleiss’ kappa (κ) was calculated for the IOA analyses. Results: IOA on static was moderate with κ values of 0.46, 0.42, 0.40, 0.45, and 0.38 for the Kwak-, ACR-, EU-, Korean-TIRADS, and ATA Guidelines, respectively, while the IOA on cine-loops was fair with κ values of 0.41, 0.38, 0.37, 0.36, and 0.34 for the Kwak-, ACR-, EU-, Korean-TIRADS, and ATA Guidelines, respectively. The overall IOA was superior in static images versus cine-loops (p = 0.024). Among other findings, the subgroup analyses (related to age, gender, US certificates, number of thyroid US per week, and RSSs experience) particularly showed that the experience of the observers in using RSSs had a significant influence on the IOA. Conclusions: The overall IOA (all twelve observers and all five RSSs) was superior on static US images in comparison to cine-loops. Furthermore, the overall IOA of the five US features revealed superior κ values of the static images over cine-loops. However, this impact was significantly lower when the observers were highly experienced in the use of US RSSs of TNs.

La stratificazione preoperatoria del rischio di malignità dei noduli tiroidei è un momento diagnostico fondamentale per ridurre il numero di procedure chirurgiche non necessarie. Nei noduli ipofunzionanti (noduli freddi), specialmente quelli con citologia indeterminata, l’imaging scintigrafico molecolare ottenuto dopo la somministrazione di 99mTc-Metossi-Isobutil-Isonitrile (99mTc-MIBI) può essere un utile strumento diagnostico per escludere la natura maligna. Infatti, il mancato accumulo del 99mTc-MIBI nel nodulo ipofunzionante è indice di benignità (valore predittivo negativo fino al 100 ≥-19

Aim Thyroid scintigraphy enables the depiction of the functional status of thyroid nodules (TNs) with both, 99mTc-pertechnetate and 123Iodine. The functional status is relevant for diagnostic procedures for the differentiation of benign and malignant TNs. The aim of this study was to examine the current frequencies of hyper-, hypo- and isofunctioning TNs in Germany and to estimate the risk of malignancy with regard to functional status. Methods In 11 study centers, a minimum of 100 nodules per center were consecutively enrolled between July 2019 and April 2020. Inclusion criteria were: newly diagnosed nodule, nodule’ size of 10 mm or more, thyroid scintigraphy. Exclusion criteria were: completely cystic TNs, patients with prior radioiodine therapy or thyroid surgery. The risk of malignancy was estimated for hyper- and hypofunctioning TNs. Results Overall, 849 patients (72 % women) with 1262 TNs were included. Patients’ age ranged from 18 to 90 years. Most TNs were hypofunctioning (n=535, 42%) followed by isofunctioning TNs (n=488, 39%) and hyperfunctioning TNs (n=239, 19%). When only TNs with a maximum size of 2 cm or more were considered the rate of hyperfunctioning and hypofunctioning TNs increased (to 27% and 49%) while isofunctioning TNs decreased. Only one of all hyperfunctioning TNs was malignant. In hypofunctioning nodules, the malignancy rate was estimated at 10%. Conclusion In Germany, the proportion of hyperfunctioning TNs is approximately 20% and increases in larger TNs to up to 27%. Due to the low risk of malignancy in hyperfunctioning TNs, no further procedures to rule out malignancy are necessary. The risk of malignancy of hypofunctioning TNs is significantly higher. Thus, a thyroid scintigraphy is a useful diagnostic tool in Germany.

Ziel/Aim Ermittlung der Verteilung szintigraphisch hyperfunktioneller („heißer; h“), hypofunktioneller („kalter; k“) und indifferenter („i“) Schilddrüsenknoten sowie der Malignitätsrate „h“ und „k“ Knoten in Deutschland, um den – in den letzten Jahren international kritisch hinterfragten – Stellenwert der Schilddrüsenszintigraphie im Abklärungsalgorithmus von Schilddrüsenknoten zu eruieren, da es hierzu keine aktuellen nationalen Daten gibt.

Purpose This study evaluates the quantitative effect of improved MR-based attenuation correction (AC), including bone segmentation and the HUGE method for truncation correction in PET/MR whole-body hybrid imaging specifically of oncologic patients with bone metastasis and using various radiotracers. Methods Twenty-three patients that underwent altogether 28 whole-body PET/MR examinations with findings of bone metastasis were included in this study. Different radiotracers ( 18 F-FDG, 68 Ga-PSMA, 68 Ga-DOTATOC, 124 I–MIBG) were injected according to appropriate clinical indications. Each of the 28 whole-body PET datasets was reconstructed three times using AC with (1) standard four-compartment μ-maps (background air, lung, muscle, and soft tissue), (2) five-compartment μ-maps (adding bone), and (3) six-compartment μ-maps (adding bone and HUGE truncation correction). The SUV max of each detected bone lesion was measured in each reconstruction to evaluate the quantitative impact of improved MR-based AC. Relative difference images between four- and six-compartment μ-maps were calculated. MR-based HUGE truncation correction was compared with the PET-based MLAA truncation correction method in all patients. Results Overall, 69 bone lesions were detected and evaluated. The mean increase in relative difference over all 69 lesions in SUV max was 5.4 ± 6.4% when comparing the improved six-compartment AC with the standard four-compartment AC. Maximal relative difference of 28.4% was measured in one lesion. Truncation correction with HUGE worked robust and resulted in realistic body contouring in all 28 exams and for all 4 different radiotracers. Truncation correction with MLAA revealed overestimations of arm tissue volume in all PET/MR exams with 18 F-FDG radiotracer and failed in all other exams with radiotracers 68 Ga-PSMA, 68 Ga-DOTATOC, and 124 I- MIBG due to limitations in body contour detection. Conclusion Improved MR-based AC, including bone segmentation and HUGE truncation correction in whole-body PET/MR on patients with bone lesions and using various radiotracers, is important to ensure best possible diagnostic image quality and accurate PET quantification. The HUGE method for truncation correction based on MR worked robust and results in realistic body contouring, independent of the radiotracers used.

The impact of a method for MR-based respiratory motion correction of PET data on lesion visibility and quantification in patients with oncologic findings in the lung was evaluated. Twenty patients with one or more lesions in the lung were included. Hybrid imaging was performed on an integrated PET/MR system using 18F-FDG as radiotracer. The standard thoracic imaging protocol was extended by a free-breathing self-gated acquisition of MR data for motion modelling. PET data was acquired simultaneously in list-mode for 5-10 mins. One experienced radiologist and one experienced nuclear medicine specialist evaluated and compared the post-processed data in consensus regarding lesion visibility (scores 1-4, 4 being best), image noise levels (scores 1-3, 3 being lowest noise), SUVmean and SUVmax. Motion-corrected (MoCo) images were additionally compared with gated images. Non-motion-corrected free-breathing data served as standard of reference in this study. Motion correction generally improved lesion visibility (3.19 ± 0.63) and noise ratings (2.95 ± 0.22) compared to uncorrected (2.81 ± 0.66 and 2.95 ± 0.22, respectively) or gated PET data (2.47 ± 0.93 and 1.30 ± 0.47, respectively). Furthermore, SUVs (mean and max) were compared for all methods to estimate their respective impact on the quantification. Deviations of SUVmax were smallest between the uncorrected and the MoCo lesion data (average increase of 9.1% of MoCo SUVs), while SUVmean agreed best for gated and MoCo reconstructions (MoCo SUVs increased by 1.2%). The studied method for MR-based respiratory motion correction of PET data combines increased lesion sharpness and improved lesion activity quantification with high signal-to-noise ratio in a clinical setting. In particular, the detection of small lesions in moving organs such as the lung and liver may thus be facilitated. These advantages justify the extension of the PET/MR imaging protocol by 5-10 minutes for motion correction.

Background: The aim of this study was to evaluate the value of 18F–FDG PET/CT (PET/CT) and MRI for local and/or whole-body restaging of adenoid cystic carcinoma of the head and neck (ACC). Methods: Thirty-six patients with ACC underwent conventional MRI of the head and neck and a whole-body PET/CT and were analysed with regards to detection of a local tumor recurrence, lymph node or distant metastases. A consensus interpretation of all available imaging data was used as reference standard. Sensitivity, specificity, diagnostic accuracy, positive and negative predictive values were calculated for MRI and PET/CT. Results: The sensitivity of PET/CT and MRI was 96% (89%), specificity 89% (89%), PPV 96% (96%), NPV 89% (73%) and accuracy 94% (89%) for detection of local tumors. Additionally, PET/CT revealed lymph node metastases in one patient and distant metastases in 9/36 patients. In three patients secondary primaries were found. Conclusions: Whole-body PET/CT in addition to MRI of the head and neck improves detection of local tumour and metastastic spread in ACC.

Ziel/Aim Diese Studie untersuchte den quantitativen Einfluss der verbesserten MR-basierten Schwächungskorrektur (AC) mit Knochenmodell und Verzerrungskorrektur von Ganzkörper PET/MR mit verschiedenen Tracern bei Patienten mit Knochenläsionen

Evaluation der diagnostischen Wertigkeit der 18F-FDG PET/MRT im Vergleich zur MRT im Ganzkörperstaging von Frauen mit Verdacht auf Rezidiv eines Beckentumors.

To evaluate the diagnostic performance of 18F–FDG PET/MRI for whole-body staging and potential changes in therapeutic management of women with suspected recurrent pelvic cancer in comparison with MRI alone.

To evaluate and compare the diagnostic potential of 18F‐fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18FDG‐PET/MRI) and MRI for recurrence diagnostics after primary therapy in patients with adenoid cystic carcinoma (ACC).

Recent studies have shown an excellent correlation between PET/MR and PET/CT hybrid imaging in detecting lesions. However, a systematic underestimation of PET quantification in PET/MR has been observed. This is attributable to two methodological challenges of MR-based attenuation correction (AC): (1) lack of bone information, and (2) truncation of the MR-based AC maps (μmaps) along the patient arms. The aim of this study was to evaluate the impact of improved AC featuring a bone atlas and truncation correction on PET quantification in whole-body PET/MR.

Das Ziel der vorliegenden Arbeit war die Evaluation des Nutzens einer Kontrastmittelgabe und einer Diffusionsbildgebung (DWI) in der 18F-FDG PET/MRT für die Bestimmung des Ann Arbor Stadiums bei Lymphom-Patienten.

Background: The aim of this study was to evaluate the value of 18F–FDG PET/CT (PET/CT) and MRI for local and/or whole-body restaging of adenoid cystic carcinoma of the head and neck (ACC). Methods: Thirty-six patients with ACC underwent conventional MRI of the head and neck and a whole-body PET/CT and were analysed with regards to detection of a local tumor recurrence, lymph node or distant metastases. A consensus interpretation of all available imaging data was used as reference standard. Sensitivity, specificity, diagnostic accuracy, positive and negative predictive values were calculated for MRI and PET/CT. Results: The sensitivity of PET/CT and MRI was 96% (89%), specificity 89% (89%), PPV 96% (96%), NPV 89% (73%) and accuracy 94% (89%) for detection of local tumors. Additionally, PET/CT revealed lymph node metastases in one patient and distant metastases in 9/36 patients. In three patients secondary primaries were found. Conclusions: Whole-body PET/CT in addition to MRI of the head and neck improves detection of local tumour and metastastic spread in ACC.

INTRODUCTION:Focal 18 F-Fluoride uptake on blood-pool phase PET represents regional hyperaemia, while it indicates osteoblastic activity on mineralization phase PET. This study investigates the link between regional hyperaemia and osteoblastic activity in inflammatory and chronic lesions of ankylosing spondylitis (AS) of the sacroiliac joints (SIJ) using dual-phase 18 F-Fluoride PET/MRI.METHODS:Thirteen patients (six men, seven women, age: 37 ± 10 years) with active AS prospectively underwent dual-phase 18 F-Fluoride PET/MRI. Blood-pool phase PET was acquired 6 min and mineralization phase PET 40 min after injection of 158 ± 8 MBq 18 F-Fluoride. SIJ quadrants (SQ) were assessed regarding inflammatory lesions represented by bone marrow oedema (BME), chronic AS lesions such as erosion, fat deposition (FD), sclerosis and ankylosis on MRI, and regarding focal 18 F-Fluoride uptake on both PET datasets. Image quality (IQ) of both PET datasets and MRI was evaluated using a 4-point Likert scale.RESULTS:Of 104 SQ, there were 63.4% SQ with FD, 42.3% SQ with BME, 26.9% SQ with erosions, 26% SQ with sclerosis and 10.6% SQ with ankylosis. BME alone was associated with focal 18 F-Fluoride uptake in 63.6% SQ on blood-pool phase and 90.9% SQ on mineralization phase 18 F-Fluoride PET/MRI. Instead, FD, erosion, sclerosis, ankylosis were not associated with focal 18 F-Fluoride uptake on either blood-pool or mineralization phase 18 F-Fluoride PET/MRI. SQ showing BME alone or a combination of BME and chronic AS lesions had a significantly higher percentage of focal 18 F-Fluoride uptake on blood-pool phase and mineralization phase PET/MRI than SQ showing AS lesions without BME (P < 0.001). Both 18 F-Fluoride PET datasets provided high IQ, albeit IQ of mineralization phase PET was superior to blood-pool phase PET (P < 0.001).CONCLUSION:Dual-phase 18 F-Fluoride PET/MRI of the SIJ showed that inflammatory rather than chronic AS lesions are associated with regional hyperaemia and osteoblastic activity.

To investigate whether differences in thoracic tumour staging between 18F-FDG PET/CT and PET/MR imaging lead to different therapeutic decisions in Non-Small Cell Lung Cancer (NSCLC).