Positron emission tomography (PET) using 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) is widely used in oncology and other fields. In [18F]FDG PET images, increased muscle uptake is observed owing exercise load or muscle tension, in addition to malignant tumors and inflammation. Moreover, we occasionally observe non-pathological solitary or unilateral skeletal muscle uptake, which is difficult to explain the strict reason. In most cases, we can interpret them as not having pathological significance. However, it is important to recognize such muscle uptake patterns to avoid misdiagnoses with pathological ones. Therefore, the teaching point of this pictorial essay is to comprehend the patterns of solitary or asymmetrical skeletal muscle uptake seen in routine [18F]FDG-PET scans. As an educational goal, you will be able to mention muscles where intense physiological [18F]FDG uptake can be observed, differentiate between physiological muscle uptake and lesion, and discuss with any physicians or specialists about uncertain muscle uptake.

Introduction: Myocardial flow reserve (MFR) derived from 13 N-ammonia positron emission tomography (PET) is used to predict adverse cardiac events in the patients with coronary artery disease (CAD). Right ventricular (RV) strain measured by magnetic resonance imaging (MRI) is used to evaluate RV function. This study aimed to evaluate the prognostic value of combined MFR and RV strain measured by hybrid 13 N-ammonia PET/MRI in patients with CAD. Methods: Sixty-one patients who underwent 13 N-ammonia PET/MRI were enrolled. MFR was calculated from dynamic acquisition of 13 N-ammonia PET under vasodilator stress with intravenous injection of adenosine. RV global longitudinal strain (GLS) was measured by wall motion tracking techniques in cine-mode MRI. The end points were defined as a composite of all-cause death, myocardial infarction, sustained ventricular arrhythmia, hospitalization due to decompensated heart failure, and revascularization. Results: At a follow-up of 2.8 ± 1.9 years, 21 events occurred. Kaplan-Meier analysis showed that the event-free rate was significantly lower in the group with MFR < 1.80 than that with MFR ≥ 1.80 (P < 0.001, Figure a). Additionally, the event-free rate was significantly lower in the group with RVGLS > –18.22% than that with RVGLS ≤ –18.22% (P = 0.025, Figure b). After dividing the patients into four groups by the median MFR and the median RVGLS, the event-free rate was lowest in the combined group of MFR < 1.80 and RVGLS > -18.22% than any other groups (P < 0.001, Figure c). In the Cox proportional hazard analysis, MFR and RVGLS were independent predictors of cardiac adverse events in the patients with CAD. Conclusion: The simultaneous assessment of MFR and RV strain by 13 N-ammonia PET/MRI revealed the feasibility of precise risk stratification for cardiac events in patients with CAD.

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Background: Larger sample volume can be obtained in one needle pass using an aspiration-type semi-automatic cutting biopsy needle (STARCUT® aspiration-type needle; TSK Laboratory, Tochigi, Japan) in comparison to the conventional semi-automatic cutting biopsy needle. Objective: To evaluate and compare the safety and effectiveness of aspiration-type semi-automatic cutting biopsy needles and non-aspiration-type biopsy needles when performing computed tomography (CT)-guided core needle biopsies (CNBs). Methods: A total of 106 patients underwent CT-guided CNB for chest lesions between June 2013 and March 2020 at our hospital. Non-aspiration-type cutting biopsy needles were used in 47 of these patients, while aspiration-type needles were used in the remaining 59 patients. All needles used were 18- or 20-gauge biopsy needles. Parameters, like forced expiratory volume in 1-second percent (FEV1.0%), the maximum size of the target lesion, puncture pathway distance in the lung, number of needle passes, procedure time, diagnostic accuracy, and incidence of complications, were measured. Comparisons were made between the needle-type groups. Results: No significant difference was observed in terms of diagnostic accuracy. However, the procedure time was shorter and a lesser number of needle passes were required with the aspiration-type cutting biopsy needle compared to the non-aspiration-type needle. Pneumothorax and pulmonary hemorrhage were the complications encountered, however, their incidence was not significantly different between the two types of needles. Conclusions: The aspiration-type semi-automatic cutting biopsy needle had similar diagnostic accuracy as the non-aspiration-type biopsy needle, with added advantages of a lesser number of needle passes and shorter procedure time.