植田 高弘

PURPOSE: The present study directly compared the quantitative capabilities of regional perfusion and pulmonary functional change assessments among electrocardiography (ECG)- and photoplethysmography (PPG)-monitored phase-resolved functional lung (PREFUL) MRI and dynamic contrast-enhanced (CE) perfusion MRI in thoracic oncologic patients. METHODS: Seventeen thoracic oncologic patients prospectively underwent ECG- and PPG-monitored PREFUL MRI, dynamic CE-perfusion MRI, and pulmonary function tests. ECG- and PPG-monitored perfusion-weighted PREFUL MRI (PW-MRI) and quantitative perfusion maps from dynamic CE-perfusion MRI were generated. Regional perfusions were determined using ROI measurements. For each patient, the overall perfusion from each method was determined as the average ROI measurement value. To determine the relationship between regional perfusion among all methods, Pearson's correlations were performed. Tukey's honest significant difference test was performed to compare regional perfusion among ventral, middle, and dorsal slice positions on ECG- and PPG-monitored PW-MRI and quantitative perfusion maps. To assess the pulmonary functional loss evaluation capability of each MRI method, each overall perfusion was correlated with %VC and %FEV1 using Pearson's correlation. RESULTS: The correlation of regional perfusion between ECG- and PPG-monitored PW-MRI was significant and good (r = 0.79, P < 0.0001). However, the correlations between ECG- or PPG-monitored PW-MRI and quantitative perfusion maps were assessed as significant and fair (ECG: r = 0.4, P < 0.0001; PPG: r = 0.36, P < 0.0001). ECG- and PPG-monitored PW-MRI demonstrated significantly higher perfusion than the quantitative perfusion map (P < 0.0001). Furthermore, ECG-and PPG-monitored PW-MRI and quantitative perfusion maps had significant and moderate correlations (%VC: 0.60 ≤ r ≤ 0.63, P < 0.05; %FEV1: 0.52 ≤ r ≤ 0.69, P < 0.05). CONCLUSION: ECG- and PPG-monitored PREFUL MRI had similar potential to dynamic CE-perfusion MRI for quantitatively assessing regional perfusion and pulmonary functional changes in thoracic oncologic patients. Furthermore, PPG-monitored PREFUL MRI showed little difference in regional perfusion evaluation compared with ECG-monitored PREFUL MRI and the potential to play a complementary role in this setting.

BACKGROUND: We compared the capabilities of quantitatively assessed paired inspiratory-expiratory area-detector computed tomography (ADCT) for pulmonary functional loss and disease severity evaluations between upright and supine ADCT in matched progressive pulmonary fibrosis (PPF) patients. MATERIALS AND METHODS: This retrospective cohort consisted of age-, sex-, and underlying disease-matched patients with PPF who underwent paired inspiratory-expiratory CT on upright ADCT (n = 40) and supine ADCT (n = 40), pulmonary function tests, and disease severity assessment. Based on CT data, the absolute values of the logarithm of the Jacobian determinant and warp-field magnitude of the whole lung and all lobes were calculated. Stepwise regression analyses were performed. RESULTS: On supine ADCT, both indices of the left lower lobe (LLL) were the first and only steps for pulmonary function test results and CT-assessed disease severity (absolute value of the logarithm of the Jacobian determinant: 0.139 ≤ r2 ≤ 0.175, 0.007 ≤ p ≤ 0.018; absolute value of the warp-field magnitude: 0.371 ≤ r2 ≤ 0.447, p < 0.001). However, on upright ADCT, both indices indicated that LLL was the first step and the right lower lobe was the second step for pulmonary function test results and CT-assessed disease severity (0.503 ≤ r2 ≤ 0.674, p < 0.001 or 0.000 < p ≤ 0.006 and 0.474 ≤ r2 ≤ 0.652, 0.002 ≤ p ≤ 0.045, respectively). CONCLUSION: Upright ADCT has equal to or better potential than supine ADCT for detecting pulmonary functional loss and evaluating disease severity when paired inspiratory-expiratory ADCT is applied in PPF patients. RELEVANCE STATEMENT: Upright ADCT has superior potential to supine ADCT for pulmonary functional loss and disease severity evaluations when paired inspiratory-expiratory ADCT is performed in patients with progressive pulmonary fibrosis (PPF). KEY POINTS: Matched progressive pulmonary fibrosis patients compared functional loss and disease severity evaluations between inspiratory-expiratory upright and supine area-detector CT. Clinical parameters demonstrated better correlations with upright than with supine inspiratory-expiratory area-detector CT. Warp-field magnitude showed better correlations with disease severities than the logarithm of the Jacobian determinant on each area-detector CT.

PURPOSE: The purpose of this study was to directly compare diagnostic capability of inguinal herniation between upright area-detector CT (ADCT) and conventional supine ADCT under the Valsalva maneuver. MATERIALS AND METHODS: This retrospective study included 209 patients with 360 inguinal herniations and 123 patients without inguinal hernias. All patients underwent supine and upright ADCT for the evaluation of abdominal wall hernias within one week between May 2023 and March 2024. From this cohort, a total of 120 of 360 inguinal hernias and 120 of 304 non-inguinal hernias were computationally selected, and the probability of hernia was visually assessed by two board-certified general and abdominal radiologists with 5-point scales to assess subtypes of herniation. The final score for each hernia was determined as consensus of two investigators. To determine the capability of diagnosis for inguinal herniation in selected lesion groups, diagnostic performance was compared between upright and supine ADCTs using an ROC analysis. Then, sensitivity (SE), specificity (SP), and accuracy (AC) for differentiation of inguinal from non-inguinal hernias were compared between the two methods using McNemar's test. RESULTS: The area under the curve (AUC) of upright ADCT (AUC = 0.96) was significantly larger than that of supine ADCT (AUC = 0.93, p < 0.0001). Sensitivity (SE) and accuracy (AC) of upright ADCT (SE: 87.5 %, AC: 93.8 %) were significantly higher than those of supine ADCT (SE: 73.3 %, p < 0.0001; AC: 86.7 %, p < 0.0001). CONCLUSION: Upright ADCT has better potential for the diagnosis and subtype classification of inguinal herniation than conventional supine ADCT when applied under the Valsalva maneuver.

OBJECTIVES: The purpose of this study was to determine the utility of conjugate gradient reconstruction (CG Recon) and deep learning reconstruction (DLR) for reducing scan time while maintaining the image quality and nodule detection capability on lung MRI with ultrashort TE (UTE-MRI) as compared with grid reconstruction (Grid Recon). MATERIALS AND METHODS: In the in vitro and in vivo studies, the NEMA phantom and 35 patients with pulmonary nodules were scanned by UTE-MRI with original (TEoriginal), 1/2 (UTE1/2), and 1/4 (UTE1/4) spoke numbers obtained by both methods and reconstructed with and without DLR. In this study, the standard protocol was UTEoriginal obtained by Grid Recon without DLR. Then, signal-to-noise ratios (SNR) of the phantom, lung and lesion were assessed. In the in vivo study, overall image quality and nodule detection capability were visually assessed on each UTE-MRI. Quantitative and qualitative indices were then compared between the standard protocol and others. Finally, a receiver operating characteristic (ROC) analysis was performed to compare the standard and other protocols. RESULTS: In in vitro and in vivo studies, all SNRs were significantly different between the standard protocol and each UTE-MRI with CG Recon and DLR (p < 0.05). Overall image quality of the standard protocol differed significantly from that of all UTE1/4s (p < 0.05). The area under the curve of each UTEOriginal obtained by CG Recon was significantly larger than that of the standard protocol (p < 0.05). CONCLUSION: CG Recon and DLR can reduce scan time while maintaining image quality and nodule detection capabilities on lung UTE-MRI. KEY POINTS: Question To determine the utility of conjugate gradient reconstruction (CG Recon) to reduce scan time without nodule detection capability on MRI with ultrashort TE (UTE-MRI). Findings Nodule detection capability was not significantly decreased by CG Recon with or without deep learning reconstruction when reducing scan time from the standard UTE-MRI protocol. Clinical relevance Conjugate gradient reconstruction (CG Recon) and deep learning reconstruction (DLR) have the potential to reduce scan time while maintaining image quality and nodule detection capability in lung MR imaging with ultrashort TE.