Imaging features of benign mass lesions in the nasal cavity and paranasal sinuses according to the 2017 WHO classification

The World Health Organization (WHO) 2017 classification of head and neck tumors has been just published and has reorganized tumors of the nasal cavity and paranasal sinuses. In this classification, three new entities (seromucinous hamartoma, NUT carcinoma, and biphenotypic sinonasal sarcoma) were included, while the total number of tumors has been reduced by excluding tumors if they did not occur exclusively or predominantly in this region. Among these entities, benign tumors were classified as sinonasal papillomas, respiratory epithelial lesions, salivary gland tumors, benign soft tissue tumors, or other tumors. In contrast, inflammatory diseases often show tumor-like appearances. The imaging features of these benign tumors and tumor-like inflammatory diseases often resemble malignant tumors, and some benign lesions should be given attention in the follow-up period and before surgery to avoid recurrence, malignant transformation, or massive bleeding. Understanding the CT and MR imaging features of various benign mass lesions is clinically important for appropriate therapy. The purpose of this article is to describe the clinical characteristics and imaging features of each of clinically important nasal and paranasal benign mass lesions, as classified according to the WHO 2017 classification of head and neck tumors, along with some inflammatory diseases.     

<Superscript>18</Superscript>F-FPYBF-2, a new F-18 labelled amyloid imaging PET tracer: biodistribution and radiation dosimetry assessment of first-in-man <Superscript>18</Superscript>F-FPYBF-2 PET imaging

Objective

Recently, a benzofuran derivative for the imaging of β-amyloid plaques, 5-(5-(2-(2-(2-¹⁸F-fluoroethoxy)ethoxy)ethoxy)benzofuran-2-yl)- N-methylpyridin-2-amine (¹⁸F-FPYBF-2) has been validated as a tracer for amyloid imaging and it was found that ¹⁸F-FPYBF-2 PET/CT is a useful and reliable diagnostic tool for the evaluation of AD (Higashi et al. Ann Nucl Med,  https://doi.org/10.1007/s12149-018-1236-1, 2018). The aim of this study was to assess the biodistribution and radiation dosimetry of diagnostic dosages of ¹⁸F-FPYBF-2 in normal healthy volunteers as a first-in-man study.

Methods

Four normal healthy volunteers (male: 3, female: 1; mean age: 40?±?17; age range 25–56) were included and underwent ¹⁸F-FPYBF-2 PET/CT study for the evaluation of radiation exposure and pharmacokinetics. A 10-min dynamic PET/CT scan of the body (chest and abdomen) was performed at 0–10 min and a 15-min whole-body static scan was performed six times after the injection of ¹⁸F-FPYBF-2. After reconstructing PET and CT image data, individual organ time–activity curves were estimated by fitting volume of interest data from the dynamic scan and whole-body scans. The OLINDA/EXM version 2.0 software was used to determine the whole-body effective doses.

Results

Dynamic PET imaging demonstrated that the hepatobiliary and renal systems were the principal pathways of clearance of ¹⁸F-FPYBF-2. High uptake in the liver and the gall bladder, the stomach, and the kidneys were demonstrated, followed by the intestines and the urinary bladder. The ED for the adult dosimetric model was estimated to be 8.48?±?1.25 µSv/MBq. The higher absorbed doses were estimated for the liver (28.98?±?12.49 and 36.21?±?15.64 µGy/MBq), the brain (20.93?±?4.56 and 23.05?±?5.03µ Gy/MBq), the osteogenic cells (9.67?±?1.67 and 10.29?±?1.70 µGy/MBq), the small intestines (9.12?±?2.61 and 11.12?±?3.15 µGy/MBq), and the kidneys (7.81?±?2.62 and 8.71?±?2.90 µGy/MBq) for male and female, respectively.

Conclusions

The ED for the adult dosimetric model was similar to those of other agents used for amyloid PET imaging. The diagnostic dosage of 185–370 MBq of ¹⁸F-FPYBF-2 was considered to be acceptable for administration in patients as a diagnostic tool for the evaluation of AD.

     

Comparison between manual and automatic image registration in image-guided radiation therapy using megavoltage cone-beam computed tomography with an imaging beam line for prostate cancer

This study aimed to compare and assess the compatibility of the bone-structure-based manual and maximization of mutual information (MMI)-algorithm-based automatic image registration using megavoltage cone-beam computed tomography (MV-CBCT) images acquired with an imaging beam line. A total of 1163 MV-CBCT images from 30 prostate cancer patients were retrospectively analyzed. The differences between setup errors in three directions (left–right, LR; superior–inferior, SI; anterior–posterior, AP) of both registration methods were investigated. Pearson’s correlation coefficients (r) and Bland–Altman agreements were evaluated. Agreements were defined by a bias close to zero and 95% limits of agreement (LoA) less than ±?3 mm. The cumulative frequencies of the absolute differences between the two registration methods were calculated to assess the distributions of the setup error differences. There were significant differences (p?<?0.001) in the setup errors between both registration methods. There were moderate (SI, r?=?0.45) and strong positive correlation coefficients (LR, r?=?0.74; AP, r?=?0.72), whereas the 95% LoA (bias?±?1.96?×?standard deviation of the setup error differences) were ??1.61?±?4.29 mm (LR), ??0.41?±?5.45 mm (SI), and 0.67?±?4.29 mm (AP), revealing no agreements in all directions. The cumulative frequencies (%) of the cases with absolute setup error differences within 3 mm in each direction were 80.83% (LR), 81.86% (SI), and 90.71% (AP), with all directions having large proportions of >?3-mm differences. The MMI-algorithm-based automatic registration is not compatible with the bone-structure-based manual registration and should not be used alone for prostate cancer.     

The remnant preservation technique reduces the amount of bone tunnel enlargement following anterior cruciate ligament reconstruction

Purpose

The aim of the present study was to investigate the correlation between postoperative tunnel enlargement after ACLR and remnant tissue preservation using the hamstring tendon.

Methods

One hundred and ninety-two subjects (male, n = 101; female, n = 91; mean age 27.1) who had undergone double-bundle ACL reconstruction were included in the present study. The patients were divided into two groups: the remnant tissue preservation group (Group R) and the non-remnant tissue preservation group (Group N). Computed tomographic scans of the operated knee were obtained at 2 weeks and 6 months after surgery. The area of the tunnel aperture for the anteromedial femoral tunnel (FAMT), posterolateral femoral tunnel (FPLT), anteromedial tibial tunnel (TAMT), and posterolateral tibial tunnel (TPLT) was measured. The area at 2 weeks after ACLR was subtracted from the area at 6 months after ACLR and then divided by the area at 2 weeks after ACLR. The differences in the outcomes and characteristics of the two groups were evaluated.

Results

Seventy-seven knees were classified into Group R, and 115 knees were classified into Group N. The age, gender, and body mass index did not differ to a statistically significant extent. The percentages of FAMT and TAMT enlargement in Group R were significantly smaller in comparison with Group N (P = 0.003 and P = 0.03, respectively). The percentage of FPLT and TPLT enlargement in the two groups did not differ to a statistically significant extent.

Conclusion

The remnant-preserving technique reduces the amount of bone tunnel enlargement. The present findings indicate the advantages of the remnant-preserving ACLR technique, and therefore the remnant-preserving technique should be recommended.

Level of evidence

II.

     

Comparison of regional lower limb glucose metabolism in older adults during walking

Glucose metabolism in lower limb muscles during walking has an important role in gait efficiency and endurance. The purpose of this study was to identify differences in muscle activity during walking between healthy young and older adults using positron emission tomography (PET) and [¹⁸F]fluorodeoxyglucose (FDG). Ten healthy young men (24 ± 2 years) and 10 healthy older men (76 ± 2 years) participated in this study. An FDG PET assessment of each subject was conducted after 50 min of treadmill walking. The images of glucose metabolism in 18 regions of interest were estimated from the standardized uptake value (SUV). The older adults showed a significantly higher FDG uptake in the semitendinosus, biceps femoris, iliacus, gluteus minimus, gluteus medius, and gluteus maximus muscles than the young adults: FDG uptake ratios of SUV in the old to SUV in the young were 3.02, 3.19, 1.66, 1.64, 3.68, and 3.05, respectively. During walking, the FDG uptake in older adults was higher in hamstrings and deep layer hip muscles than that in young adults. These results suggest that intervention to facilitate efficient muscle activity during walking should be practiced to improve gait endurance in older adults with impaired walking patterns.     

Dumbbell-shaped thoracic hibernoma: computed tomography and magnetic resonance imaging findings

Hibernoma is an uncommon, benign soft tissue tumor that arises in brown adipose tissue. The computed tomography (CT) and magnetic resonance imaging (MRI) findings of hibernomas are similar to those of well-differentiated liposarcoma or angiolipoma. We report the unique appearance of a rare thoracic wall hibernoma, which appeared as a dumbbell-shaped lipomatous tumor across an intercostal region. A dynamic contrast-enhanced study on MRI revealed early enhancement, which corresponded to the branching low-signal intensity on T2-weighted images of the mass.     

Treatment of a malignant esophageal fistula with a Gore-Tex-covered flexible nitinol stent

In order to treat fistulated esophageal cancer using a flexible stent, a covered flexible stent was constructed by wrapping a nitinol stent with a thin sheet of Gore-Tex, preserving the stents original advantages of flexibility and a low-profile introducer system. This stent was used to perform standard radiotherapy in a case of fistulated esophageal cancer.     

Validation of the cingulate island sign with optimized ratios for discriminating dementia with Lewy bodies from Alzheimer’s disease using brain perfusion SPECT

Objective

Dementia with Lewy bodies (DLB) is often cited as the second most common dementia after Alzheimer’s disease (AD). It is clinically important to distinguish DLB from AD because specific side effects of antipsychotic drugs are limited to DLB. The relative preservation of cingulate glucose metabolism in the posterior cingulate gyri versus that in the precuni, known as the cingulate island sign (CIS), in patients with DLB compared with AD is supposed to be highly specific for diagnosing DLB. In a previous study, using brain perfusion SPECT, the largest value (0.873) for the area under the receiver operating characteristic (ROC) curve (AUC) for differentiating DLB from AD was obtained with the ratio of the posterior cingulate gyri from an early Alzheimer’s disease-specific hypoperfusion volume of interest (VOI) versus the medial occipital lobe. Two purposes of this study are as follows: one is optimization of VOI setting for calculating CIS values and the other is to evaluate their accuracy and simultaneously to retest the method described in our previous paper.

Methods

We conducted a retest of this SPECT method with another cohort of 13 patients with DLB and 13 patients with AD. Furthermore, we optimized VOIs using contrast images obtained from group comparisons of DLB and normal controls; the same 18 patients with DLB and 18 normal controls examined in our previous study. We obtained DLB-specific VOIs from areas where brain perfusion was significantly decreased in DLB. As the numerators of these ratios, early Alzheimer’s disease-specific VOIs were used after subtracting DLB-specific VOIs. The DLB-specific VOIs were used as the denominator.

Results

In retest, the obtained AUC was 0.858 and the accuracy, sensitivity, and specificity were 84.6, 84.6, and 84.6%, respectively. The ROC curve analysis with these optimized VOIs yielded a higher AUC of 0.882; and the accuracy, sensitivity, and specificity of these new CIS ratios were 84.6, 92.3, and 76.9%, respectively, with a threshold value of 0.281.

Conclusion

Optimized CISs using brain perfusion SPECT are clinically useful for differentiating DLB from AD.

     

Effective luminance deterioration of medical liquid crystal displays in clinical use

The objective of this work was to evaluate the maximum luminance (L _max) level of medical liquid crystal displays (LCDs) as a function of backlight hours (BLH) annually. The L _max values for 249 2-megapixel color LCDs (RadiForce RX210, EIZO Corporation) were measured in February 2014, 2015, and 2016. Four near-range luminance meters and the built-in type luminance meters, each with an LCD, were used for the measurements. The average and standard deviation (SD) of BLH measured in 2014 was 15,371 ± 8219 h. Four, twenty, and thirty-nine LCDs failed in the constancy tests performed in February 2014, 2015, and 2016, respectively, i.e., they were unable to output 170 cd/m². The SD of L _max increased each year and as BLH became longer. In conclusion, evaluation of L _max as a function of BLH during constancy testing will help predict the decrease in L _max of a clinically used medical color LCD.