Zero Echo Time Magnetic Resonance Imaging; Techniques and Clinical Utility in Musculoskeletal System.

Zero echo time (ZTE) sequence is recent advanced magnetic resonance technique that utilizes ultrafast readouts to capture signals from short-T2 tissues. This sequence enables T2- and T2* weighted imaging of tissues with short intrinsic relaxation times by using an extremely short TE, and are increasingly used in the musculoskeletal system. We review the imaging physics of these sequences, practical limitations, and image reconstruction, and then discuss the clinical utilities in various disorders of the musculoskeletal system. ZTE can be readily incorporated into the clinical workflow, and is a promising technique to avoid unnecessary radiation exposure, cost, and time-consuming by computed tomography in some cases. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 1.

Feasibility of Breath-Hold Zero TE Magnetic Resonance Imaging Sequence for Evaluation of Pulmonary Arteriovenous Malformations After Embolotherapy.

ABSTRACT: We obtained breath-hold zero TE (ZTE) magnetic resonance imaging for the evaluation of pulmonary arteriovenous malformations before and after embolotherapy. To the best of our knowledge, there have been no reports of ZTE for the entire lung imaging in single breath-hold scan time such as 20 seconds. Breath-hold ZTE magnetic resonance imaging can be a useful technique for magnetic resonance-based follow-up of vascular lung diseases without using contrast media, reducing the undesired artifacts from metallic devices.

Ion-pairing assemblies of π-extended anion-responsive organoplatinum complexes.

PtII complexes of π-extended dipyrrolyldiketones were synthesized as anion-responsive π-electronic molecules. The dipyrrolyldiketone PtII complexes exhibited red-shifted absorption and photoluminescence properties. In the solid state, [1 + 1]-type anion complexes formed charge-by-charge ion-pairing assemblies when combined with countercations. Detailed theoretical studies of the packing structures revealed favorable interactions between the planar anion complexes and π-electronic cations.

Pt^II complexes of π-extended dipyrrolyldiketones, introducing arylethynyl substituents, in the form of anion complexes exhibited the formation of charge-by-charge assemblies with π-electronic cations via ⁱπ­ⁱπ interactions.

Intensity-modulated radiation therapy for intermediate-risk prostate cancer: does ADT still have an impact in the dose-escalated external beam radiation therapy era?

BACKGROUND: This study aimed to investigate the effect of androgen deprivation therapy (ADT) on the survival of intermediate-risk prostate cancer (IR-PCA) patients treated with dose-escalated external beam radiation therapy (DE-EBRT), and to determine the group that will benefit from ADT. METHODS: We analysed 620 IR-PCA patients treated with DE-EBRT at two institutions. Variables were adjusted using the stabilised inverse probability of treatment weighting method (sIPTW) between radiation therapy (RT) and RT plus ADT groups. Biochemical relapse-free survival (bRFS) rate and overall survival (OS) rate were compared using Kaplan-Meier analysis and log-rank test. Cox proportional hazard analysis (CPH) was conducted to detect unfavorable risk factors. RESULTS: This study included 405 patients; with 217 and 188 patients in the RT and RT plus ADT groups, respectively. The prescribed radiation dose was 78 Gy in 39 fractions. The median follow-up time was 82.0 months. After sIPTW-adjustment, 214.3 and 189.7 patients were assigned to the RT and RT plus ADT groups, respectively. The 7-year bRFS and OS were 89.3% and 94.6% in RT group and 92.3% and 91.0% in RT plus ADT group, respectively. Before and after sIPTW adjustment, no statistically significant differences were found in these endpoints between treatment groups. Multivariate CPH for bRFS revealed Gleason score (GS) 4 + 3 as an unfavorable risk factor, and ADT improved biochemical control of them. CONCLUSION: ADT may not always be effective in all Japanese IR-PCA patients treated with DE-EBRT, but it can improve biochemical control in patients with GS 4 + 3.

An effective double gene knock-in strategy using small-molecule L755507 in the medaka fish (Oryzias latipes).

Homology-directed repair (HDR)-mediated genome editing has become a powerful method for altering chromosomal sequences in a seamless and accurate manner. However, the low efficiency of HDR in most cells hinders the establishment of desired strains harboring accurately modified genomes. To enhance HDR-mediated knock-in events, we explored two approaches, namely low-temperature incubation and chemical compound administration using medaka embryos after microinjection. We validated the performance of each method by calculating the knock-in efficiencies according to the expression area of fluorescent protein in the embryos. The in vivo assay indicated that the reduction in temperature did not promote HDR events, whereas among the nine compounds screened, the small molecule L755507 could enhance the HDR-mediated targeted integration of reporter cassettes. Additionally, the L755507-based approach allowed for the simultaneous integration of two different DNA fragments into the two targeted loci, that is, double knock-in. Our established knock-in system combining L755507, donor plasmids, and the CRISPR/Cas9 nickase system can reduce the workload for genetically modified strain generation, thus accelerating studies on the molecular mechanisms of biological phenomena.

Natural History of Unruptured Visceral Artery Aneurysms Due to Segmental Arterial Mediolysis and Efficacy of Transcatheter Arterial Embolization: A Retrospective Multiinstitutional Study in Japan.

OBJECTIVE. The purpose of this study was to clarify the natural history of unruptured visceral artery aneurysms due to segmental arterial mediolysis and the efficacy of transcatheter arterial embolization. MATERIALS AND METHODS. Patients with a pathologic or clinical diagnosis of visceral artery aneurysms due to segmental arterial mediolysis between 2005 and 2015 were enrolled. For patients with clinical diagnoses, images were collected and assessed by central radiologic review. To clarify the natural history of unruptured aneurysms, the morphologic changes were assessed. The efficacy and safety of transcatheter arterial embolization for aneurysms due to segmental arterial mediolysis were evaluated. RESULTS. Forty-five patients with 123 aneurysms due to segmental arterial mediolysis were enrolled. Among the 123 aneurysms, 70 unruptured aneurysms were evaluated for natural history. Forty-five of the 70 (64%) aneurysms had no change in morphology. Among the other 25 aneurysms, nine (13% of the 70) were reduced in size, 13 (19%) disappeared, and three (4%) were newly found at follow-up. Aneurysms of the middle colic artery were ruptured in 10 of 11 (91%) cases. Transcatheter arterial embolization was performed on 45 aneurysms and was successful in all cases but caused slight arterial injury in three cases (6.7%). CONCLUSION. At initial diagnosis, unruptured aneurysms due to segmental arterial mediolysis are likely to be stable or to resolve, but the risk of rupture of aneurysms of the middle colic artery appears high. Transcatheter arterial embolization is a useful treatment, but careful manipulation is necessary.

Vertebrobasilar Infarction Due to Bow Hunter's Syndrome in a Patient with Rheumatoid Arthritis: A Case Report.

A 60-year-old woman with a 37-year history of rheumatoid arthritis (RA) had a sudden onset of headache. Head MRI showed acute multiple infarctions in the vertebrobasilar region, and MR angiography showed stenosis of the right vertebral artery (VA). 3D-CT angiography of the craniovertebral junction showed atlantoaxial subluxation and stenosis of the right VA just distal to the transverse foramen of C2, which was due to osteophytes and degenerative changes secondary to RA. Digital subtraction angiography clearly demonstrated occlusion of the right VA during rightward head rotation. Based on those findings, rotatory instability at C1-2 was considered as the primary cause of the vertebrobasilar infarctions, and Bow Hunter's syndrome was diagnosed. The patient underwent C1-5 posterior fixation, and brain infarction has not recurred.

[Does Surgeons' Experience Affect the Surgical Outcomes of Total Arch Replacement?]

OBJECTIVES: Total arch replacement( TAR) is used to be a complicated and quite invasive aortic procedure. To perform TAR safely and effectively under all circumstances, we have constructed standardization of the procedures of TAR. The aim of this study is to analyze the impact of surgeons' experience on surgical outcome of TAR to evaluate our standardization. METHODS: From January 2008 to December 2020, 346 consecutive patients (mean age 73.6±10.2) underwent elective TAR through a median sternotomy at our institute. TAR was performed by three types of surgeon classified by their experience( A:over 20 years, B:15~20 years, C:under 15 years). The surgical outcomes were examined. Our standard approach include( 1) meticulous selection of arterial cannulation site and type of arterial cannula;(2) antegrade selective cerebral perfusion;(3) maintenance of minimal tympanic temperature between 20 ℃ and 23 ℃;(4) early rewarming just after distal anastomosis;(5) maintaining fluid balance below 1,000 ml during cardiopulmonary bypass. RESULTS: The operative cases were 227 in A, 86 in B and 33 in C. Surgeon A operated more complicated TAR with higher operative risk compared with B and C. The hospital mortality and major complication rate was not significant difference among surgeons( hospital mortality A:3.5%, B:2.3%, C:3.0%). Multivariate analysis showed the surgeons' experience was not associated with hospital mortality and major complications. Long-term outcomes were also compatible among three groups. CONCLUSIONS: Our standardization for TAR seemed to be an useful approach to eliminate the impact of surgeon experience on surgical outcomes if the type of surgeon was appropriately selected according to the level of operative difficulty.

Radiomics Approach Outperforms Diameter Criteria for Predicting Pathological Lateral Lymph Node Metastasis After Neoadjuvant (Chemo)Radiotherapy in Advanced Low Rectal Cancer.

BACKGROUND: Advanced low rectal cancer has a non-negligible risk of lateral pelvic lymph node (LPLN) metastasis (LPLNM) and lateral local recurrence (LR) after neoadjuvant (chemo)radiotherapy and total mesorectal excision. LPLN dissection (LPLND) reduces LR but increases postoperative complications and sexual/urinary dysfunction. OBJECTIVE: The aim of this study was to develop a new radiomics-based prediction model for LPLNM in patients with rectal cancer. METHODS: A total of 247 patients with rectal cancer and enlarged LPLNs treated by (chemo)radiotherapy and LPLND were enrolled in this retrospective, multicenter study. LPLN radiomic features were extracted from pretreatment portal venous-phase computed tomography images. A radiomics score of LPLN was constructed based on the least absolute shrinkage and selection operator regression in a primary cohort of 175 patients. Model performance was assessed in terms of discrimination, calibration, and decision curve analysis, and was externally validated in 72 patients. RESULTS: The radiomics score showed significantly better discrimination compared with pretreatment short-axis diameter measurements in both the primary (area under the curve [AUC] 0.91 vs. 0.83, p = 0.0015) and validation (AUC 0.90 vs. 0.80, p = 0.0298) cohorts. Decision curve analysis also indicated the superiority of the radiomics score. In a subanalysis of patients with a short-axis diameter ≥ 7 mm, the radiomics nomogram, incorporating the radiomics score and LPLN shrinkage to ≤ 4 mm, had better discrimination compared with a model incorporating only LPLN shrinkage in both cohorts. CONCLUSIONS: Radiomics-based prediction modeling provides individualized risk estimation of LPLNM in rectal cancer patients treated with (chemo)radiotherapy, and outperforms measurements of pretreatment LPLN diameter.

CRISPR/Cas9 nickase-mediated efficient and seamless knock-in of lethal genes in the medaka fish Oryzias latipes.

The CRISPR/Cas system offers new opportunities for targeted gene modifications in a wide range of organisms. In medaka (Oryzias latipes), a vertebrate model organism, a wild-type Cas9-based approach is commonly used to establish desired strains, however, its use in lethal genes is still challenging due to excess gene disruptions triggered by DNA double strand breaks (DSBs). To overcome this problem, we aimed to develop a new knock-in system using Cas9 nickase (Cas9n) that can reduce DNA DSBs. We revealed that Cas9n allowed reduction of the DSB-induced unwanted mutagenesis via non-homologous end-joining at both on- and off- target sites. Further, with a new donor plasmid (p2BaitD) that provides a linear template through Cas9n-mediated nicks, we successfully integrated reporter cassettes via homology-directed repair (HDR) into all three loci tested, including a lethal gene. In the experiment targeting the lethal gene, the combination of p2BaitD and Cas9n achieved higher survival rates than the Cas9-based approach, which enabled the desired knock-in founders. Additionally, through a technical blend of our knock-in system with a recently developed One-step mating protocol, we successfully established a homozygous knock-in strain in one generation period. This study presents evidence of an effective method to generate an HDR-mediated gene knock-in in medaka and other organisms, which is useful for establishing screening platforms for genes or drugs toxicity or other applications.

[Impact of Aperture Shape Controller on Volumetric Modulated Arc Therapy Treatment Planning for Nasopharyngeal Cancer].

PURPOSE: The aperture shape controller (ASC) decreases the complexity of the multi-leaf collimator (MLC) aperture for volumetric modulated arc therapy (VMAT). The purpose of this study was to evaluate the effect of ASC settings on the VMAT plan quality. METHOD: First, VMAT plans were created (ASC=off) for three test patterns of The American Association of Physicists in Medicine (AAPM) Task Group 119 (TG-119) and 20 cases of nasopharyngeal cancer. Next, for these VMAT plans, only the ASC settings were changed from very low (complexity reduction: low) to very high (complexity reduction: high) in five steps, and VMAT plans were created respectively. To evaluate the created VMAT plans per each ASC settings, we analyzed the modulation complexity score (MCSV) and dosimetric parameters for the planning target volume (PTV) and organ at risk (OAR). RESULT: In three test patterns, there were no major dosimetric differences between the VMAT plans. In nasopharyngeal cancer, the mean MCSV were 0.413, 0.325, 0.320, 0.307, 0.303, and 0.272 for very high, high, moderate, low, very low, off settings, respectively. Therefore, the most complex MLC aperture was off, followed by very low, low, moderate, high, and very high. In terms of dosimetric parameters, the VMAT plans created using the very high setting showed an increase of D2% in the PTV and worse OAR sparing than that using other ASC settings. On the other hand, the dosimetric results for the very low to moderate setting obtained similar results to those for the off setting, respectively. CONCLUSION: The ASC was able to decrease the complexity of the MLC aperture according to the setting level. From very low to moderate settings, a plan equivalent to the off setting could be created in terms of dose parameters.

Identification of Heschl's gyrus on phase difference enhanced imaging.

Background The white matter in the Heschl's gyrus (HG-WM) may appear differently to the other gyri on phase difference enhanced imaging (PADRE), which can enhance the myelin density. Purpose To evaluate the signal intensity (SI) of HG-WM using the PADRE technique and to compare the images with susceptibility-weighted imaging (SWI)-like images. Material and Methods The participants included 19 normal controls (38 HGs; mean age, 60.1 years; age range, 28-80 years). Coronal PADRE and SWI-like images were acquired using a 3T magnetic resonance (MR) system. The SI of the HG-WM was classified into three grades based on a comparison with the SI of the superior temporal gyrus: Grade 1, isointense; Grade 2, slightly hypointense, and Grade 3, markedly hypointense. Results In the assessment of the SI of the HG-WM, the HG-WM appeared hypointense in all 38 sites of the 19 participants; the hypointensity corresponded to Grade 2 in 13 (34%) images and Grade 3 in 25 (66%) images. On the other hand, the HG-WM was classified as Grade 1 (isointense) in all of the SWI-like images. Conclusion The HG-WM appears hypointense on PADRE, which probably reflects the higher myelin content. PADRE may be useful for identifying the HG through the assessment of the SI of the HG-WM.

[L-shaped Partial Upper Sternotomy Approach for Aortic Valve Replacement].

Transcatheter aortic valve implantation is a recent innovation in the treatment of severe aortic stenosis. On the other hand, several reports suggested that minimally invasive aortic valve replacement (MICS-AVR) is likely to be associated with reduced postoperative discomfort and faster recovery. Of note, an upper partial sternotomy for isolated aortic valve replacement( L-shaped MICS-AVR) has been accepted as the most common approach to the MICS-AVR. Since October 2013, we have preformed L-shaped MICS-AVR at our hospital. In L-shaped MICS-AVR group(16 patients, 74.4±8.7 years),there was no operative mortality and any other complication including reexploration for postoperative bleeding, wound infection, peri-valvular leakage, pulmonary complication like re-intubation or minitracheostomy. To demonstrate the benefits of this approach, over-octogenarian subgroup( n=7)was analyzed and compared with the isolated AVR using a conventional sternotomy (C-AVR, n=10)in the same period. A trend was seen toward better postoperative course in the L-shaped MICS-AVR group than in the C-AVR group;however, this difference was not statistically significant. The mean duration of cardiopulmonary bypass(120±29 min vs 93±24 min, p=0.005)and cross clamp time(151±36 min vs 124±32 min, p=0.038)were significantly longer than C-AVR. We believe that more clinical experience is required to clarify the benefits of this approach and we must more consider the preoperative images for the attainment of the excellent exposure. Moreover, the concomitant use of this new device and L-shaped MICS-AVR may enable a big improvement in the future.

Quantitative susceptibility mapping in patients with systemic lupus erythematosus: detection of abnormalities in normal-appearing basal ganglia.

OBJECTIVES: To evaluate whether quantitative susceptibility mapping (QSM) can be employed to detect abnormalities within normal-appearing basal ganglia on conventional MRI in patients with neuropsychiatric systemic lupus erythematosus (NPSLE). METHODS: For 33 SLE patients (13 NPSLE and 20 non-NPSLE patients) and 23 age/sex-matched controls, two radiologists independently measured the mean QSM and R2* values in various brain structures that appeared to be normal on conventional MR images. These values in each brain structure were compared among the two SLE groups and controls. RESULTS: Regarding the putamen, the NPSLE patients showed significantly higher QSM values than the non-NPSLE patients and controls (p < 0.05). For the lateral globus pallidus, both SLE groups showed significantly higher QSM values than the controls (p < 0.05). The R2* values were not significantly different between both SLE groups. The NPSLE patients showed a significant correlation between the mean QSM values in putamen and the disease duration (r = 0.63, p < 0.05). For the interobserver agreement, the QSM value was superior to the R2* value (0.690 vs. 0.446, Kendall W value). CONCLUSIONS: QSM can be used to identify increased susceptibility of the basal ganglia appearing to be normal on conventional MR images in NPSLE patients. KEY POINTS: • QSM values in the putamen are significantly higher in NPSLE than non-NPSLE. • NPSLE patients show correlation between QSM values in the putamen and disease duration. • QSM is more sensitive than R2* mapping for detecting subtle changes.

Internal structures of the globus pallidus in patients with Parkinson's disease: evaluation with quantitative susceptibility mapping (QSM).

OBJECTIVES: The aim of this study was to assess the susceptibility change in medial and lateral globus pallidus (GPm and GPl) related to age separately, using quantitative susceptibility mapping (QSM) and to determine whether QSM can depict GPm in Parkinson's disease (PD) patients. METHODS: QSM was performed in 19 PD patients and in 41 normal control (NC) subjects. First, we quantitatively analysed age-related changes in QSM value in NC for GPl and GPm by a manual region of interest (ROI) technique. Then, in PD patients and age-matched NC subjects, we evaluated the depiction of GPm on QSM images qualitatively. RESULTS: In NC, the QSM value within GPl significantly increased gradually with age (r = 0.32, p = 0.04), whereas it did not change with age in GPm. The average QSM value was significantly larger for GPl than for GPm (205 vs 191, p < 0.05). In both PD patients and age-matched NC, the depiction of GPm on QSM images was good in most cases (87 %, 33 of 38 sides in PD patients) mainly because of the differences in susceptibility between GPm and GPl. CONCLUSIONS: The QSM value in GPl increases gradually with age, which allows for the identification of GPm in elderly PD subjects.

Real-World Clinical Efficacy of Antifibrotic Agents for Idiopathic Pulmonary Fibrosis: A Single-Center Retrospective Study in Japan.

BACKGROUND: The antifibrotic drugs, nintedanib and pirfenidone, inhibit the decline in forced vital capacity in patients with idiopathic pulmonary fibrosis (IPF). Nintedanib also inhibits the onset of acute exacerbation and reduces the risk of all-cause mortality. However, their effectiveness in real-world practice remains unclear. Our study aimed to investigate the changes in forced vital capacity, survival period, causes of death, and risk factors for mortality in patients with IPF receiving antifibrotic drugs. METHODS: This retrospective study enrolled Japanese patients who visited Toho University Sakura Medical Center who were diagnosed with IPF and received antifibrotic drugs. RESULTS: We included 102 patients [mean age ± standard deviation (SD): 71.8 ± 7.5 years], of whom 76 were males. The decline in forced vital capacity (mean ± SD) during the antifibrotic therapy period was - 154 ± 259 mL/year, which was significantly lower than before the antifibrotic therapy period (- 484 ± 589 mL/year; n = 80, p = 0.003). Altogether, 52 deaths were confirmed, and the median survival time from antifibrotic therapy initiation was 38.0 months (95% confidence interval: 25.9-50.1 months). Acute exacerbation accounted for 9.6% of all deaths (95% confidence interval: 1.6-17.6). The decline in forced vital capacity during antifibrotic therapy was a risk factor for mortality. CONCLUSIONS: In actual clinical practice in Japan, antifibrotic drugs suppressed the gradual decline in forced vital capacity, which is a risk factor for mortality. However, the median survival period remained poor at 38 months.

Enhanced solid-state phosphorescence of organoplatinum π-systems by ion-pairing assembly.

Anion binding and ion pairing of dipyrrolyldiketone PtII complexes as anion-responsive π-electronic molecules resulted in photophysical modulations, as observed in solid-state phosphorescence properties. Modifications to arylpyridine ligands in the PtII complexes significantly impacted the assembling behaviour and photophysical properties of anion-free and anion-binding (ion-pairing) forms. The PtII complexes, in the presence of guest anions and their countercations, formed various anion-binding modes and ion-pairing assembled structures depending on constituents and forms (solutions and crystals). The PtII complexes emitted strong phosphorescence in deoxygenated solutions but showed extremely weak phosphorescence in the solid state owing to self-association. In contrast, the solid-state ion-pairing assemblies with tetraalkylammonium cations exhibited enhanced phosphorescence owing to the formation of hydrogen-bonding 1D-chain PtII complexes dispersed by stacking with aliphatic cations. Theoretical studies revealed that the enhanced phosphorescence in the solid-state ion-pairing assembly was attributed to preventing the delocalisation of the electron wavefunction over PtII complexes.

Alterations in the fillet quality of myostatin-knockout red sea bream Pagrus major: Preliminary insights into nutritional, compositional, and textural properties.

Myostatin (MSTN) is a negative regulator of skeletal muscle growth and a popular target for enhancing the productivity of farmed fish. We previously developed an mstn-knockout breed of the aquaculture fish red sea bream (Pagrus major) using genome editing technology. However, little is known about the effects of mstn disruption on the fillet quality of red sea bream and other fish species. In this study, we used fillets of mstn-deficient red sea bream to evaluate their compositional and textural changes during refrigeration. Compared to the wild type, the mutant fillets exhibited an increase in moisture content and a decrease in drippings, indicating an enhanced water-holding capacity. Furthermore, the mutant fillets showed increased water retention and marginally lower collagen content, resulting in lower breaking force, an index of texture. In conclusion, we demonstrated that mstn disruption alters the compositional and textural properties of red sea bream fillets.

Usefulness of Olfactory Bulb Measurement in 3D-FIESTA in Differentiating Parkinson Disease from Atypical Parkinsonism.

BACKGROUND AND PURPOSE: Parkinson disease is a prevalent disease, with olfactory dysfunction recognized as an early nonmotor manifestation. It is sometimes difficult to differentiate Parkinson disease from atypical parkinsonism using conventional MR imaging and motor symptoms. It is also known that olfactory loss occurs to a lesser extent or is absent in atypical parkinsonism. To the best of our knowledge, no study has examined olfactory bulb changes to differentiate Parkinson disease from atypical parkinsonism, even in an early diagnosis, and its association with conventional MR imaging findings. Hence, we aimed to assess the utility of olfactory bulb measurements in differentiating Parkinson disease from atypical parkinsonism even in the early stage. MATERIALS AND METHODS: In this retrospective study, we enrolled 108 patients with Parkinson disease, 13 with corticobasal syndrome, 15 with multiple system atrophy, and 17 with progressive supranuclear palsy who developed parkinsonism. Thirty-nine age-matched healthy subjects served as controls. All subjects underwent conventional MR imaging and 3D FIESTA for olfactory bulb measurements using manual ROI quantification of the cross-sectional olfactory bulb area using the coronal plane. Bilateral olfactory bulb measurements were averaged. For group comparisons, we used the Welch t test, and we assessed diagnostic accuracy using receiver operating characteristic analysis. RESULTS: Patients with Parkinson disease had a mean olfactory bulb area of 4.2 (SD, 1.0 mm2), significantly smaller than in age-matched healthy subjects (6.6 [SD, 1.7 mm2], P < .001), and those with corticobasal syndrome (5.4 [SD, 1.2 mm2], P < .001), multiple system atrophy (6.5 [SD, 1.2 mm2], P < .001), and progressive supranuclear palsy (5.4 [SD, 1.2 mm2], P < .001). The receiver operating characteristic analysis for the olfactory bulb area measurements showed good diagnostic performance in differentiating Parkinson disease from atypical parkinsonism, with an area under the curve of 0.87, an optimal cutoff value of 5.1 mm2, and a false-positive rate of 18%. When we compared within 2 years of symptom onset, the olfactory bulb in Parkinson disease (4.2 [SD, 1.1 mm2]) remained significantly smaller than in atypical parkinsonism (versus corticobasal syndrome (6.1 [SD, 0.7 mm2]), P < .001; multiple system atrophy (6.3 [SD, 1.4 mm2]), P < .001; and progressive supranuclear palsy (5.2 [1.3 mm2], P = .003, respectively). CONCLUSIONS: 3D FIESTA-based olfactory bulb measurement holds promise for distinguishing Parkinson disease from atypical parkinsonism, especially in the early stage.

Prediction of Tumor PD-L1 Expression in Resectable Non-Small Cell Lung Cancer by Machine Learning Models Based on Clinical and Radiological Features: Performance Comparison With Preoperative Biopsy.

OBJECTIVE: We investigated if PD-L1 expression can be predicted by machine learning using clinical and imaging features. METHODS: We included 117 patients with c-stage I/II non-small cell lung cancer who underwent radical resection. A total of 3951 radiomic features were extracted by defining the tumor (within tumor contour), rim (contour ±3 mm) and exterior (contour +10 mm) on preoperative contrast computed tomography. After feature selection by Boruta algorithm, prediction models of tumor PD-L1 expression (22C3: ≥1%, <1%) of resected specimens were constructed using Random Forest: radiomics, clinical, and combined models. Their performance was evaluated by 5-fold cross-validation, and AUCs were compared using Delong test. Next, study groups were categorized as patients without biopsy (training set), and those with biopsy (test set). Predictive ability of biopsy was compared to each prediction model. RESULTS: Of 117 patients (66 ± 10 years old, 48% male), 33 (28.2%) had PD-L1≥1%. Mean AUC of PD-L1≥1% for the validation set in radiomics, clinical, and combined models were 0.80, 0.80, and 0.83 (P = .32 vs. clinical model), respectively. The diagnosis of malignancy was made in 22 of 38 (58%) patients with attempted biopsies, and PD-L1 was measurable in 19 of 38 (50%) patients. Diagnostic accuracies of PD-L1≥1% from 19 determinable biopsies and 38 all attempted biopsies were 0.68 and 0.34, respectively. These were out performed by machine learning: 0.71, 0.71, and 0.74 for radiomics, clinical, and combined models, respectively. CONCLUSIONS: Our machine learning could be an adjunctive tool in estimating PD-L1 expression prior to neoadjuvant treatment, particularly when PD-L1 is indeterminable with biopsy.