論文

© 2018, The Japanese Society of Nuclear Medicine. Purpose: Quantification of the tracer distribution would add objectivity to the visual assessments of dopamine transporter (DAT) single photon emission computed tomography (SPECT) data. Our study aimed to evaluate the diagnostic utility of fractal dimension (FD) as a quantitative indicator of tracer distribution and compared with the conventional quantitative value: specific binding ratio (SBR). We also evaluated the utility of the combined index SBR/FD (SBR divided by FD). Materials and methods: We conducted both clinical and phantom studies. In the clinical study, 150 patients including 110 patients with Parkinsonian syndrome (PS) and 40 without PS were enrolled. In the phantom study, we used a striatal phantom with the striatum chamber divided into two spaces, representing the caudate nucleus and putamen. The SBR, FD, and SBR/FD were calculated and compared between datasets for evaluating the diagnostic utility. Mann–Whitney test and receiver-operating characteristics (ROC) analysis were used for analysis. Results: ROC analysis revealed that the FD value had high diagnostic performance [the areas under the curve (AUC) = 0.943] and the combined use of SBR and FD (SBR/FD) delivered better results than the SBR alone (AUC, 0.964 vs 0.899; p < 0.001). The sensitivity, specificity, and accuracy, respectively, were 79.1, 85.0, and 80.7% with SBR, 84.5, 97.5, and 88.0% with FD, and 92.7, 87.5, and 91.3% with SBR/FD. Conclusion: Our results confirmed that the FD value is a useful diagnostic index, which reflects the tracer distribution in DAT SPECT images. The combined use of SBR and FD was more useful than either used alone.

© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Background: Although the structural changes of the scalp in androgenetic alopecia (AGA) have been reported, these changes have been poorly understood. It is expected that modern MRI would visualize the scalp anatomy in vivo. This study aimed to explore whether AGA causes (a) changes in the thickness of the scalp, (b) anatomical changes in the hair follicles, and (c) changes in the signal intensity of MRI. Materials and Methods: Twenty-seven volunteers underwent MRI for hair and scalp (MRH) and were categorized into two according to the Hamilton-Norwood Scale: the “AGA group” and the “normal group.” Two radiologists analyzed the thickness and signal intensity of the scalp, and the depth of hair follicles. These measurements were compared between the two groups. Results: The thickness of the hypodermis and the entire scalp was significantly thinner in the AGA group than in the control group. The AGA group had significantly shallower depth of hair follicles and relative depth of the hair follicles to that of the entire scalp than the normal group. The hypodermis showed higher signal intensity in the AGA group than the normal group. Conclusion: MRH allowed noninvasive visualization of the scalp anatomy and demonstrated the thinner nature of the entire scalp and hypodermis, along with the shallower depth of the hair follicles in the AGA group in comparison to the normal group. Additionally, MRH demonstrated the increased MR signal intensity in the scalp associated with AGA. MRH may be a promising new method for quantitative and objective analyses of AGA.

A 68-year-old man underwent total cystectomy, urethrectomy preserving fossa naviculars, and an Indiana pouch urinary diversion in 1997. The histopathology was UC, G3, pT4 (prostate). Nine years after the operation, he had multiple metastases to the inguinal and paraaortic lymph nodes (LNs), and he complained of erosion around the glans. Histological diagnosis of the glans revealed recurrent UC to the urethra of the glans. We considered the possibility that the inguinal LN metastasis was due to lymphatic spread from a remnant urethral recurrence. Thus, a partial penectomy and inguinal LN dissection were undertaken. Systemic chemotherapy was administered. Remnant urethral recurrence after urethrectomy preserving the fossa navicularis and inguinal LN metastasis are rare. © 2011 Japanese Urological Association.

Background: Endoscopic endonasal transsphenoidal surgery (EES) is the gold standard for pituitary adenoma (PA) resection. The sphenoid sinus (SS), a highly variable anatomic structure, is located in the center of the cranial base. It has previously been reported that poor pneumatization of the lateral recess of the SS (LRSS) increases the difficulty level of the surgery and the risk of neural and vascular injury. However, to date no studies have evaluated the association between LRSS volume and PAs removal rate by EES. Methods: The present study analyzed 23 consecutive patients with new-onset PAs categorized as Knosp Grades 3 and 4 who underwent EES. A retrospective radiographic analysis was conducted on patients undergoing magnetic resonance imaging and high-resolution computed tomography scans. Results: Among PA cases categorized as Knosp 3 and 4, no significant association was found between the whole tumor's resection rate and LRSS volume (R = 0.08, P = 0.70). However, a significant association was found between cavernous sinus (CS) tumors' removal rate and LRSS volume (R = 0.52, P = 0.011). The same results were achieved in PAs with a Knosp Grade 4, with a stronger correlation (R = 0.60, P = 0.014). Conclusion: The development of LRSS pneumatization affects the removal rate of CS tumors in PAs. Preoperative analysis of LRSS development should be considered when planning EES against PA with CS invasion.

Objective To evaluate the suitability of preoperative multiparametric magnetic resonance imaging (MRI) positivity as a predictor of biochemical recurrence after radical prostatectomy (RP). Patients and Methods We reviewed the clinical records of patients who underwent either standard RP or laparoscopic RP between January 2005 and December 2009 at our institution. Patients who received radiotherapy or androgen deprivation therapy before surgery were excluded. A total of 314 patients met the study inclusion criteria. Cox proportional hazard regression models were used for analyses. In accordance with the criteria in the established guidelines, a radiologist scored the probability of the presence of prostate cancer using a five-point scale of diagnostic confidence level. The highest confidence level of any pulse sequence was considered as the evaluation result. Results MRI positivity was significantly associated with a high clinical stage (cT ≥ 2; P = 0.039), a high positive biopsy core rate (≥0.2; P < 0.001), a high biopsy Gleason score ([GS] ≥8; P < 0.001) and a high pathological GS (≥8; P = 0.005). Univariate analysis and multivariate analysis showed that MRI positivity was a prognostic indicator in the analysis that included only preoperative variables and also in the analysis including preoperative and pathological variables. Conclusion Multiparametric MRI positivity can independently predict biochemical recurrence after RP. © 2013 The Authors. BJU International © 2013 BJU International.

Objective: Partial or complete urinary obstruction caused by a tumor itself may affect renal function and the eligibility for perioperative cisplatin-based chemotherapy in patients with upper tract urothelial carcinoma. We investigated whether the status of preoperative hydronephrosis provides additional predictive information concerning changes in perioperative renal function. Methods: A total of 155 patients who underwent nephroureterectomy for upper tract urothelial carcinoma from 1997 to 2010 were identified. The association between preoperative parameters including the grade of hydronephrosis and perioperative renal function was analyzed. Results: Hydronephrosis was observed in 104 patients. The grade of hydronephrosis was 1, 2, 3 and 4 in 6 (3.9%), 25 (16.1%), 42 (27.1%) and 31 (20.0%) cases. Using a defined cut-off creatinine clearance value of ≥50 ml/min indicating eligibility for cisplatin-based chemotherapy, only 94 patients (60.6%) were eligible in the neoadjuvant setting. Of these 94 patients, 30 (31.9%) were judged to be ineligible in the adjuvant setting. Multivariate analysis demonstrated that patient age ≥70 years [P < 0.001, hazard ratio (HR) 27.9] and the absence of a higher grade hydronephrosis (P = 0.013, HR 7.40) were independent risk factors for predicting patients ineligible to receive adjuvant cisplatin-based chemotherapy. The proportion of patients ineligible to receive cisplatin-based chemotherapy changed from 40.9 to 88.6% following nephroureterectomy in patients aged ≥70 years and those with no or a lower grade hydronephrosis. Conclusions: The status of hydronephrosis is an independent predictor of eligibility to receive adjuvant cisplatin-based chemotherapy. The information on preoperative hydronephrosis and patient age may assist in part of the decision-making when considering neoadjuvant cisplatin-based chemotherapy. © The Author 2012. Published by Oxford University Press. All rights reserved.

OBJECTIVE. The purpose of our study was to evaluate the utility of diffusion-weighted MRI (DWI) for preoperative T categorization and prediction of the histopathologic grade of renal pelvic cancer. MATERIALS AND METHODS. We retrospectively evaluated 40 renal pelvic cancers from 40 patients. The MRI included T2-weighted single-shot fast spin-echo, DWI, and contrast-enhanced imaging. Two radiologists independently reviewed three image sets (T2- weighted images alone, T2-weighted plus DWI, and T2-weighted plus contrast-enhanced images) regarding tumor detection and the discrimination of locally advanced tumors. The diagnostic performance among the three image sets were compared using Cochrane test followed by McNemar tests. The apparent diffusion coefficients between two histopathologic grades were compared using the Mann-Whitney U test. RESULTS. T2-weighted imaging plus DWI enabled a high detection rate (98%, 39/40) without significant differences. For the diagnosis of T3 or higher categories, the accuracies were relatively low in all three image sets (70% each for T2-weighted imaging plus DWI and T2-weighted imaging plus contrast-enhanced imaging and 58% for T2-weighted imaging alone, p > 0.05), with sensitivities of 58%, 65%, and 54%, respectively. For discriminating tumors with macroscopic renal invasion from those with microscopic renal invasion or less, T2-weighted imaging plus DWI (93%) was significantly more accurate than T2-weighted imaging alone (75%) (p = 0.016). The mean apparent diffusion coefficient of the high-grade tumors was significantly lower than that of the low-grade tumors (p < 0.01). CONCLUSION. DWI could be used for preoperative T categorization and prediction of the histopathologic grade of renal pelvic cancer without contrast material. © American Roentgen Ray Society.

Purpose: We analyzed the prognostic impact of hydronephrosis grade on disease specific survival and evaluated whether hydronephrosis grade could preoperatively predict worse pathological outcomes in cases of upper tract urothelial carcinoma treated surgically. Materials and Methods: We identified and retrospectively reviewed the records of 91 patients who were evaluated by multidetector computerized tomography and/or magnetic resonance imaging preoperatively, and treated with nephroureterectomy at our institution from 2000 to 2009. Ipsilateral hydronephrosis was graded 0 to 4 by 2 urological radiologists blinded to clinical outcomes. We analyzed the associations between hydronephrosis grade, and pathological findings and patient outcomes. Results: Preoperatively 67 patients (73.6%) had ipsilateral hydronephrosis. Grade was 1 to 4 in 3 (3.3%), 17 (18.7%), 23 (25.3%) and 24 cases (26.4%), respectively. Higher hydronephrosis grade was significantly associated with a ureteral tumor (p = 0.0307), higher pT stage (p = 0.0002) and lymphovascular invasion (p = 0.0014). Higher hydronephrosis grade was not associated with disease specific or metastasis-free survival. On preoperative multivariate analysis high hydronephrosis grade predicted pathological T stage (T3 or greater) (HR 4.98, p = 0.0228), positive lymphovascular invasion (HR 6.37, p = 0.0022) and grade 3 (HR 2.98, p = 0.0311). Conclusions: On image analysis preoperative hydronephrosis grade was associated with features of aggressive disease and predicted an advanced pathological outcome in patients with upper tract urothelial carcinoma. This information could prove useful to select candidates for neoadjuvant chemotherapy and make decisions concerning surgical options. © 2011 American Urological Association Education and Research, Inc.

© 2017, The Japan Society of Ultrasonics in Medicine. The purpose of this technical report is to demonstrate the feasibility of contrast-enhanced ultrasonography for preoperative evaluation of the lateral extent of subcutaneous malignant soft tissue tumours. Patients with subcutaneous malignant soft tissue tumours who underwent surgery between March 2016 and May 2016 were selected for inclusion. Contrast-enhanced ultrasonography using Sonazoid® was performed 1 day before the operation. The tumour margin was determined based on contrast-enhanced ultrasonography and marked on the skin using a permanent marker. After surgery, the extent of the tumour area was determined based on microscopic findings. The distance between the edge of the tumour and the skin markings was histologically measured. The mean distance between the extent of infiltrative tumour growth based on the microscopic findings and the skin marking was 1.3 ± 1.6 mm. The greatest distance between microscopically determined tumour invasion and the skin marking was 4 mm. Contrast-enhanced ultrasonography of subcutaneous malignant soft tissue tumours was not only feasible, but also highly accurate in estimating tumour margins as well as infiltrative tumour growth compared with macroscopic and microscopic analysis, respectively.

Purpose: To compare the prognostic importance (time to major adverse cardiovascular event [MACE]) of combined computed tomography (CT) angiography and CT myocardial stress perfusion imaging with that of combined invasive coronary angiography (ICA) and stress single photon emission CT myocardial perfusion imaging. Materials and Methods: This study was approved by all institutional review boards, and written informed consent was obtained. Between November 2009 and July 2011, 381 participants clinically referred for ICA and aged 45-85 years were enrolled in the Combined Noninvasive Coronary Angiography and Myocardial Perfusion Imaging Using 320-Detector Row Computed Tomography (CORE320) prospective multicenter diagnostic study. All images were analyzed in blinded independent core laboratories, and a panel of physicians adjudicated all adverse events. MACE was defined as revascularization (>30 days after index ICA), myocardial infarction, or cardiac death; hospitalization for chest pain or congestive heart failure; or arrhythmia. Late MACE was defined similarly, except for patients who underwent revascularization within the first 182 days after ICA, who were excluded. Comparisons of 2-year survival (time to MACE) used standard Kaplan-Meier curves and restricted mean survival times bootstrapped with 2000 replicates. Results: An MACE (49 revascularizations, five myocardial infarctions, one cardiac death, nine hospitalizations for chest pain or congestive heart failure, and one arrhythmia) occurred in 51 of 379 patients (13.5%). The 2-year MACE-free rates for combined CT angiography and CT perfusion findings were 94% negative for coronary artery disease (CAD) versus 82% positive for CAD and were similar to combined ICA and single photon emission CT findings (93% negative for CAD vs 77% positive for CAD, P < .001 for both). Event-free rates for CT angiography and CT perfusion versus ICA and single photon emission CT for either positive or negative results were not significantly different for MACE or late MACE (P > .05 for all). The area under the receiver operating characteristic curve (AUC) for combined CT angiography and CT perfusion (AUC = 68; 95% confidence interval [CI]: 62, 75) was similar (P = .36) to that for combined ICA and single photon emission CT (AUC = 71; 95% CI: 65, 79) in the identification of MACE at 2-year follow-up. Conclusion: Combined CT angiography and CT perfusion enables similar prediction of 2-year MACE, late MACE, and event-free survival similar to that enabled by ICA and single photon emission CT.

Background Fingolimod (FTY) is an oral sphingosine-1-phosphate receptor modulator that reduces relapse and slows brain atrophy in multiple sclerosis (MS) patients. In addition, FTY has been shown to enhance remyelination in certain animal models. Objective To analyze feasibility of a novel q-space Myelin Map imaging to monitor demyelination and remyelination under FTY treatment in MS patients. Methods Treatment outcomes of 24 consecutive MS patients treated with FTY were analyzed. A longitudinal analysis of q-space Myelin Map imaging was performed in a subset of these patients. Results During the treatment course (average of 16.1 months), 10 patients (42%) exhibited improvement on the Expanded Disability Status Scale (EDSS) or maintained disability-free state (“optimal responders”). The average baseline age and EDSS score were significantly younger and milder in optimal responders compared to the rest of patients. A pilot longitudinal q-space Myelin Map study in 8 patients (including 4 optimal responders) showed that optimal responders tended to show signs of remyelination while exhibiting no newly evolved demyelinated lesions. Conclusion FTY may improve disability in younger patients with milder MS, and absence of demyelination activity and presence of remyelination activity may in part be associated with such improvement. q-Space Myelin Map imaging is a clinically feasible modality to monitor demyelination and remyelination in MS patients.

Background: In patients with early stage gastric cancer in the middle third of the stomach, pylorus-preserving gastrectomy (PPG) can be an option as function-preserving surgery, although its oncologic safety is not definitively defined. This issues may be overcome using the sentinel node (SN) concept. The aim of this study was to investigate the effectiveness of the SN concept in early gastric cancer patients who are candidates for PPG. Methods: One hundred fifty-six patients with middle-third location of cT1N0 gastric cancer (single lesion, <4 cm) underwent distal gastrectomy with SN mapping. As a tracer, technetium-99 tin colloid solution and blue dye were endoscopically injected into the submucosal layer surrounding the primary tumor. Results: SN detection rate was 100 % (156 of 156), and the accuracy of the nodal evaluation of metastasis was 99 % (155 of 156). Suprapyloric lymph node (LN; LN No. 5) and infrapyloric LN (LN No. 6) were detected as SNs in 6 and 14 % of the patients, respectively. We also found two cases with metastasis to LN No. 5 or LN No. 6. Discussion: When performing PPG, the possibility of LN metastasis, especially to LN No. 5 and LN No. 6, cannot be underestimated. SN mapping can play an important role to predict the possibility of metastasis to LN No. 5 and LN No. 6.

© 2018 Elsevier Inc. Background: Solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) is radiologically difficult to distinguish from meningioma, especially angiomatous meningioma. This study aimed to detect texture parameters to distinguish SFT/HPC from angiomatous meningioma using magnetic resonance imaging texture analysis with commercially available software. Methods: We retrospectively investigated textural parameters in 43 newly diagnosed SFTs/HPCs, angiomatous meningiomas, and other World Health Organization (WHO) grade I meningiomas treated at Keio University Hospital. For T1 contrast-enhanced, T2, and apparent diffusion coefficient (ADC) images, texture analyses were performed. Regions of interest were drawn manually with reference to the greater signal on contrast-enhanced T1-weighted images. ADC values and texture parameters, including kurtosis, skewness, and entropy, were evaluated and compared between these 3 groups. Results: The mean ADC value was significantly high in angiomatous meningioma, compared with SFT/HPC and other WHO grade I meningioma. ADC entropy was highest in SFT/HPC, followed by angiomatous and other WHO grade I meningioma. T2 skewness was significantly high in SFT/HPC, compared with angiomatous and other WHO grade I meningioma. T1 contrast-enhanced skewness was significantly low in angiomatous meningioma, compared with other WHO grade I meningioma. Mean ADC value distinguished SFT/HPC from angiomatous meningioma with a positive predictive value (PPV) of 62.5% and specificity of 62.5%. ADC entropy distinguished SFT/HPC from angiomatous meningioma with a PPV of 100% and specificity of 100%. ADC skewness distinguished SFT/HPC from angiomatous meningioma with a PPV of 66.7% and specificity of 71.4%. Conclusions: This study demonstrated that magnetic resonance imaging texture analysis was useful for distinguishing SFT/HPC from meningioma, especially angiomatous meningioma.

© 2019 Elsevier Inc. Background: Securing postdonation renal function in the lifetime of donors is a consequential subject for physicians, and precise prediction of postdonation renal function would be considerably beneficial when judging the feasibility of kidney donation. The aim of this study was to investigate the optimum model for predicting eGFR at 1 year after kidney donation. Methods: We enrolled 101 living-related kidney donors for the development cohort and 44 for the external validation cohort. All patients in each cohort underwent thin-sliced (1 mm)enhanced computed tomography (CT)scans. We excluded individuals with diabetes, glucose intolerance, or albuminuria from this study. We evaluated preoperative factors including age, sex, hypertension, body mass index (BMI), serum uric acid, baseline eGFR, and body surface area (BSA)-adjusted preserved kidney volume (PKV)by using 3-dimensional reconstruction of thin-sliced enhanced CT images. To detect independent predictors, we performed multivariable regression analysis. Results: The multivariable regression analysis revealed that age, BMI, predonation eGFR, and BSA-adjusted PKV were independent predictors of eGFR at 1 year after kidney donation (correlation coefficient: −0.15, −0.476, 0.521, 0.127, respectively). A strong correlation between predicted eGFR and observed eGFR was obtained in the development cohort (r = 0.839, P <.0001). The significance of this predictive model was also confirmed with the external validation cohort (r = 0.797, P <.0001). Conclusions: Age, BMI, predonation eGFR, and BSA-adjusted PKV may be useful for precisely predicting eGFR at 1 year after living kidney donation and be helpful to determine the feasibility of kidney donation from marginal donors.

© 2019 Tanaka et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Transcatheter aortic valve implantation (TAVI) in the presence of a preexisting mitral prosthesis is challenging and its influence on the morphology of mitral prosthesis and the positioning of transcatheter heart valve (THV) is unknown. We assessed the feasibility of TAVI for patients with preexisting mitral prostheses, its influence on mitral prosthesis morphology, and the positional interaction between a newly implanted THV and mitral prosthesis using serial multidetector computed tomography (MDCT). Thirty-one patients with preexisting mitral prosthesis undergoing TAVI were included. MDCT was performed before and after TAVI. Thirty patients successfully underwent TAVI without interference from preexisting mitral prosthesis. Although opening disturbance of the mechanical mitral prosthesis by the THV edge was observed in 1 patient, the patient was managed conservatively. No THV embolization occurred. THV shift during deployment occurred in 9 patients and was predicted by a larger aortic annulus area (odds ratio: 1.24 per 10 mm2, 1.03-1.49, p = 0.02), possibly because of large THVs. The mitral mean pressure gradient was slightly higher after TAVI (3.7 vs. 4.3 mmHg, p = 0.002), whereas the mitral regurgitation grade was similar. MDCT showed that the size of the mitral prosthesis housing was unchanged after TAVI. The median distance between the mitral prosthesis and THV was 2.6 mm. The postprocedural angle between the mitral prosthesis and THV was larger than the preprocedural angle between the mitral prosthesis and the left ventricular outflow tract (64° vs. 61°, p = 0.03). Thus, TAVI is feasible in the case of preexisting mitral prosthesis. Serial MDCT demonstrated favorable THV positioning and unchanged mitral prosthesis morphology after TAVI.

© 2019 The Japan Society of Hepatology Aim: Emerging evidence suggests a promising role for tumor stromal factors in characterizing patients with various types of malignancies, including hepatocellular carcinoma (HCC). We quantified the amount of collagen and elastin fibers in HCC samples with the aim of clarifying the clinico-patho-radiological significance of fiber deposition in HCC. Methods: We computed the amount of collagen and elastin fibers using digital image analysis of whole-slide images of Elastica van Gieson-stained tissues from 156 surgically resected HCCs. Furthermore, we assessed the correlations between the fiber content of HCC samples and clinical, pathological, and radiological features, including immunohistochemistry-based molecular subtypes and immunosubtypes. Results: The intratumoral area ratio of collagen in HCC tissues (median 3.4%, range 0.1–22.2%) was more than threefold that of elastin (median 0.9%, range 0.1–9.0%); there was a strong positive correlation between the amounts of collagen and elastin. Higher levels of combined collagen and elastin were significantly associated with the confluent multinodular macroscopic tumor type, the absence of a fibrous capsule, intratumoral steatosis, scirrhous tumor stroma, dense inflammatory-cell infiltrates, and the biliary/stem cell markers-positive HCC subtype. The associations of higher collagen levels with radiological findings, including heterogeneous enhancement and persistent enhancement on dynamic computed tomography, were significant. In contrast, the associations of radiological findings with elastin fibers were not significant. Intratumoral fibrous stroma in HCC comprised septum-like and perisinusoidal fibrosis; these two forms represented distinct distribution patterns of fibers and fibroblasts. Conclusion: Quantitative analysis suggested that stromal fiber-rich HCCs likely represent a distinct clinico-patho-radiological entity.

Background: Dynamic X-ray (DXR) provides images of multiple phases of breath with less radiation exposure than CT. The exact images at end-inspiratory or end-expiratory phases can be chosen accurately. Purpose: To investigate the correlation of the projected lung area (PLA) by dynamic chest X-ray with pulmonary functions. Material and Methods: One hundred sixty-two healthy volunteers who received medical check-ups for health screening were included in this study. All subjects underwent DXR in both posteroanterior (PA) and lateral views and pulmonary function tests on the same day. All the volunteers took several tidal breaths before one forced breath as instructed. The outlines of lungs were contoured manually on the workstation with reference to the motion of diaphragm and the graph of pixel values. The PLAs were calculated automatically, and correlations with pulmonary functions and demographic data were analyzed statistically. Results: The PLAs have correlation with physical characteristics, including height, weight and BMI, and pulmonary functions such as vital capacity (VC) and forced expiratory volume in one second (FEV ). VC and FEV revealed moderate correlation with the PLAs of PA view in forced inspiratory phase (VC: right, r = 0.65; left, r = 0.69. FEV1: right, r = 0.54; left, r = 0.59). Multivariate analysis showed that body mass index (BMI), sex and VC were considered independent correlation factors, respectively. Conclusion: PLA showed statistically significant correlation with pulmonary functions. Our results indicate DXR has a possibility to serve as an alternate method for pulmonary function tests in subjects requiring contact inhibition including patients with suspected or confirmed covid-19. 1 1