Initial Triple Combination Therapy Including Intravenous Prostaglandin I2 for the Treatment of Patients with Severe Pulmonary Arterial Hypertension.

Upfront combination therapy including intravenous prostaglandin I2 (PGI2-IV) is recognized as the most appropriate treatment for patients with severe pulmonary arterial hypertension (PAH). This retrospective study aimed to determine reasons why this therapy is not used for some patients with severe PAH and describe the hemodynamic and clinical prognoses of patients receiving initial combination treatment with (PGI2-IV+) or without (PGI2-IV-) PGI2-IV.Data for patients with severe PAH (World Health Organization Functional Class III/IV and mean pulmonary arterial pressure [mPAP] ≥ 40 mmHg) were extracted from the Japan Pulmonary Hypertension Registry. Overall, 73 patients were included (PGI2-IV + n = 17; PGI2-IV- n = 56). The PGI2-IV+ cohort was younger than the PGI2-IV- cohort (33.8 ± 10.6 versus 52.6 ± 18.2 years) and had higher mPAP (58.1 ± 12.9 versus 51.8 ± 9.0 mmHg), greater prevalence of idiopathic PAH (88% versus 32%), and less prevalence of connective tissue disease-associated PAH (0% versus 29%). Hemodynamic measures, including mPAP, showed improvement in both cohorts (post-treatment median [interquartile range] 38.5 [17.0-40.0] for the PGI2-IV + cohort and 33.0 [25.0-43.0] mmHg for the PGI2-IV - cohort). Deaths (8/56) and lung transplantation (1/56) occurred only in the PGI2-IV - cohort.These Japanese registry data indicate that older age, lower mPAP, and non-idiopathic PAH may influence clinicians against using upfront combination therapy including PGI2-IV for patients with severe PAH. Early combination therapy including PGI2-IV was associated with improved hemodynamics from baseline, but interpretation is limited by the small sample size.

Matching the perforating branch of the internal thoracic artery and the deep inferior epigastric artery for breast reconstruction using multi-detector row computed tomography.

PURPOSE: Matching the diameter of the deep inferior epigastric artery (DIEA) and perforating branch (PB) of the internal thoracic artery (ITA) is important for arterial anastomosis during breast reconstruction using the DIEA flap. An anatomic investigation of these arteries was performed using multidetector row computed tomography (MDCT). PATIENTS AND METHODS: Contrast-enhanced MDCT data of 50 women (aged 18-90 years) covering the neck to the groin were analyzed. The diameter of the PBs of the ITA at their origins from the first to the sixth intercostal space and of the DIEA 20 mm from the bifurcation of the external iliac artery were measured. RESULTS: The mean diameters of the right and left DIEAs were 1.53 ± 0.263 mm and 1.53 ± 0.306 mm, respectively. The diameter of the PBs in the second and third intercoastal spaces was the same as the diameter of the DIEA, bilaterally. CONCLUSION: It is suggested that anastomosis of the DIEA with PBs of the ITA in the second and third intercoastal spaces is optimal for DIEA flap grafting. Our results could contribute to making vascular anastomosis easier, thereby reducing the burden on both surgeons and patients.

Clinical Utility of the Candy-Plug Technique Using an Excluder Aortic Extender.

Objective: To describe the clinical utility and technical aspects of the candy-plug technique using an Excluder aortic extender (Ex-cuff) for false lumen (FL) occlusion in chronic aortic dissection. Materials and Methods: This is a retrospective study analyzing seven consecutive patients (mean age, 63 years; range, 44-78 years; 6 men) with aneurysmal dilatation or rupture in chronic aortic dissection. All patients had undergone thoracic endovascular aortic repair with FL occlusion using this technique. We assessed technical (deployment accuracy) and clinical (no FL backflow on the latest contrast-enhanced computed tomography) success. Results: Technical success was obtained in six patients (86%). Technical failure was caused by the malposition of the candy-plug. The mean follow-up period was 593 days (range, 222-1225 days). Clinical success was obtained in four (57%), and incomplete Amplatzer Vascular Plug (AVP) embolization was seen in two. There was no enlarged FL after the procedure, and all patients are alive during the follow-up periods. Conclusion: The candy-plug technique using an Ex-cuff may be a feasible option; however, it takes time to achieve complete AVP embolization. Therefore, using additional embolic materials should be considered when we use it for the rupture case. (This is a translation of Jpn J Endovasc Interv 2018; 19: 29-35.).

Overall assessment system of combined mammography and ultrasound for breast cancer screening in Japan.

Mammography is the only screening method with evidence in support of reduced breast cancer mortality, but yields poor accuracy outcomes in women with dense breast tissue. The Japan Strategic Anti-cancer Randomized Trial (J-START) was conducted as part of the measures implemented to deal with women with dense breast tissue. Although the sensitivity was increased, the specificity was significantly lower in the intervention group because further examination was required in all positive cases classified by either mammography or ultrasound in the J-START. To address the issue, an overall assessment system of combined mammography and adjunctive ultrasound for breast cancer screening has been developed in Japan. The basic concept is based on a comprehensive assessment that includes a mammography assessment followed by an adjunctive assessment for ultrasound similar to the clinical setting. Currently, mammography alone is recommended for population-based breast cancer screening in Japan, but additional ultrasonography is extensively available for women, especially for women with dense breasts with shared decision-making for personalized breast cancer screening. The overall assessment system is recommended for use in Japan when breast cancer screening is conducted using both mammography and ultrasonography. In this article, we summarize the advantages of the overall assessment and the simultaneous mammography/ultrasound method, the basic approach used in Japan to assign the overall assessment category for breast cancer screening, and we outline the future directions of adjunctive screening ultrasound.

Predictors of Long-term Outcomes in Patients With Connective Tissue Disease Associated With Pulmonary Arterial Hypertension.

BACKGROUND/OBJECTIVE: Pulmonary arterial hypertension (PAH) is a progressive disease characterized by increased pulmonary arterial pressure and pulmonary vascular resistance that can lead to right-sided heart failure. Connective tissue disease-associated PAH (CTD-PAH) often has poorer outcomes than idiopathic or hereditary PAH, suggesting the presence of non-PAH factors that could affect the prognoses. This cohort study aimed to identify prognostic factors for CTD-PAH management. METHODS: Medical records from April 1999 to November 2014 were reviewed to determine the time from treatment initiation to the occurrence of a clinically worsening event and the time elapsed until death. Data at baseline and the final assessment were used to identify prognostic factors associated with events using univariate and multivariate analyses by the stepwise Cox regression method. RESULTS: In 36 patients with CTD-PAH analyzed, the proportions with no clinically worsening events at 1, 2, and 3 years after treatment initiation were 62%, 52%, and 45%, respectively, with survival rates of 88%, 77%, and 77%, respectively. The regression model showed that reduced hemoglobin at baseline, reduced qR pattern in electrocardiogram lead V1, increased 60-minute erythrocyte sedimentation rate, and increased mean pulmonary arterial pressure at the final assessment were risk factors that were significantly associated with clinical worsening. For survival, no prognostic factor was identifiable. CONCLUSIONS: Hemodynamic and non-PAH factors, such as anemia, nutritional status, and inflammatory activity of the underlying CTD, which are not listed in the risk assessment table of PAH guidelines, should be strictly controlled to improve the prognosis of patients with CTD-PAH. A more multifactorial treatment strategy should be developed.

Basic Consideration for Facial Aging: Analyses of the Superficial Musculoaponeurotic System Based on Anatomy.

BACKGROUND: The superficial musculoaponeurotic system (SMAS) is an important structure to understand for face-lift surgeries. However, the detailed distribution and imaging findings of the SMAS have not been established yet. OBJECTIVES: The aim of this study was to establish the accurate distribution and computed tomography (CT) imaging findings of the SMAS based on cadaveric studies. METHODS: This study was designed in a 3-step procedure. First, 7 cadaver faces were utilized to understand the distribution and histology of the SMAS. Second, the SMAS findings from the cadaveric studies were compared with the CT images. Third, CT images were enrolled for the SMAS interpretation. RESULTS: In 7 cadaveric studies, the SMAS was observed as a subcutaneous fibro-membranous structure extending from the galea aponeurotica to the platysma muscle and laterally connected to the parotid fascia. On the medial side, it also connects with major and minor zygomatic muscles. The SMAS consisted of muscular fibers, collagen fibers, and elastic fibers histologically. Eighteen CT images (all females; age range, 21-82 years) showed the thin linear structures corresponding to the fibro-membranous structures in the cadaveric studies. CT density of the SMAS was similar with that of the muscle, and the SMAS was recognizable in all 18 subjects. CONCLUSIONS: The SMAS is a definite anatomical structure that can be demonstrated as a thin membranous structure on CT. This clinical application could be applicable to the development the cosmetic surgical procedures.

Predictive Value of VIBE using Subtraction to Evaluate Idiopathic Facial Palsy after Starting Therapy.

PURPOSE: To determine the predictive value of 3-dimensional spoiled gradient-echo volumetric interpolated breath-hold examination (VIBE) using subtraction to evaluate the short-term effect of therapy for facial palsy. MATERIALS AND METHODS: We included 97 patients with idiopathic facial palsy (52 male, 45 female; aged 50.7 ±â€Š19.4 years) who underwent MR imaging with a contrast agent after starting therapy. The mean interval between onset and therapy was 1.55 ±â€Š1.69 days, between therapy and MR imaging was 3.19 ±â€Š2.78 days, and between MR imaging and assessment of the therapeutic effect was 3.50 ±â€Š0.71 days. The degree of therapeutic effect was determined using a 4-grade scale based on the House-Brackmann scale for grading facial nerve function. Two radiologists reviewed VIBE with pre- and postcontrast subtraction using the 4-point scale. We evaluated the diagnostic performance and compared the degree of therapeutic effect and enhancement of facial nerves that were divided into 5 segments bilaterally. RESULTS: We identified 98 facial palsy initially and significant enhancement in 55 facial nerves after the start of therapy and residual palsy in 87. Sensitivity for all facial palsy was 62.0 %, specificity was 90.9 %, positive predictive value was 98.2 %, negative predictive value was 23.3 %, and accuracy was 65.3 %. Eleven patients recovered completely, 1 showed significant enhancement, and the remaining 10 did not show significant enhancement of the facial nerve. CONCLUSION: VIBE has a potential to predict the prognostic outcome and assess facial palsy after the start of therapy. KEY POINTS: · Three-dimensional spoiled gradient-echo volumetric interpolated breath-hold examination (VIBE) using subtraction can be useful to predict residual facial palsy after initial therapy.. · Strong enhancement of the facial nerve on VIBE using subtraction was associated with residual facial palsy after the start of therapy.. · Patients with a favorable prognosis did not show strong enhancement.. CITATION FORMAT: · Tomita H, Detmar K, Nakajima Y et al. Predictive Value of VIBE using Subtraction to Evaluate Idiopathic Facial Palsy after Starting Therapy. Fortschr Röntgenstr 2020; 192: 1183 - 1189.

Comparison of diagnostic precision for bone metastasis of primary breast cancer between BONENAVI version 1 and BONENAVI version 2.

OBJECTIVE: The aim of this study was to compare the diagnostic precision of bone scintigraphy with BONENAVI version 1 and BONENAVI version 2 in bone metastasis of primary breast cancer. METHODS: The subjects were 56 consecutive patients (all women, mean age 59 ± 12.7 years) who underwent bone scintigraphy with Tc-MDP and were diagnosed with bone metastasis of primary breast cancer from January 2012 to November 2014. Bone scintigraphy was performed with BONENAVI version 1 and BONENAVI version 2 to calculate artificial neural network (ANN), bone scan index (BSI), and hot-spot values, with ANN ≥ 0.5 considered to reflect bone metastasis for the calculation of sensitivity. Mean ANN, BSI, hot-spot values, and sensitivity were compared between BONENAVI version 1 and BONENAVI version 2, with P < 0.05 considered a significant difference. RESULTS: With BONENAVI version 1, mean ANN was 0.73 ± 0.29, BSI was 1.47 ± 1.85, the hot-spot value was 12.4 ± 12.5, and sensitivity was 76.8% (43/56). With BONENAVI version 2, the mean ANN was 0.86 ± 0.19, BSI was 1.53 ± 2.09, hot-spot value was 12.9 ± 15.6, and sensitivity was 94.6% (53/56). BONENAVI version 2 yielded significantly better ANN and sensitivity than BONENAVI version 1 (both P < 0.01). CONCLUSION: BONENAVI version 2 has improved sensitivity for detecting bone metastasis of primary breast cancer compared to BONENAVI version 1.

Prone "computed tomography hernia study" for the diagnosis of inguinal hernia.

PURPOSE: To improve diagnostic accuracy in cases of a suspected inguinal hernia, we perform a "CT hernia study," with the patient lying prone to allow decompression of the structures in the inguinal region. METHODS: We reviewed the records of 914 patients with a suspected inguinal hernia who underwent prone non-contrast lower abdominal CT with two rolled-up towels, 20 cm in diameter, placed transversely beneath them, at the umbilicus and hips, respectively. RESULTS: The CT hernia study yielded a diagnosis of inguinal hernia in 861 (94.2%) patients and a condition other than inguinal hernia in 43 (4.7%) patients. Hernia was not detected preoperatively but found intraoperatively in 10 patients (1.1%). Surgery was performed for a collective total of 1029 hernias in 873 patients, and the CT hernia study-based hernia detection rate was 98.3%. We compared the preoperative diagnoses of various types of hernia (Japanese Hernia Society Types I-V) against the intraoperative diagnoses and found that the CT hernia study yielded 95.8% accuracy. CONCLUSION: The CT hernia study appears to provide a high detection rate and makes differentiating the various types of inguinal hernia possible. We believe our CT hernia study adds a level of objectivity that is diagnostically beneficial.

A low perfusion-metabolic mismatch in 99m Tl and 123 I-BMIPP scintigraphy predicts poor prognosis in systemic sclerosis patients with asymptomatic cardiac involvement.

AIM: This study investigated the prognostic factors of cardiac death or cardiac failure using cardiac scintigraphy, echocardiography (UCG), and magnetic resonance imaging (MRI) in asymptomatic systemic sclerosis (SSc) patients. METHODS: We retrospectively evaluated SSc patients who had undergone cardiac scintigraphy using 99m thallium (99m Tl) and 123 I-ß-methyl-P-iodophenyl-pentadecanoic acid (123 I-BMIPP), UCG, and cardiac MRI. We calculated the mismatch score in scintigraphy by subtracting the uptake of 123 I-BMIPP from that of 99m Tl. Patients were divided into two groups according to whether they survived with no cardiac failure or subsequently proceeded to cardiac failure or death during the study period. We identified prognostic factors by analyzing 99m Tl and 123 I-BMIPP uptake, mismatch scores, UCG findings, and cardiac delayed enhancement on MRI. We also evaluated pathological evidence of myocardial fibrosis. RESULTS: Of 33 SSc cases, 11 proceeded to cardiac failure or death. There was no significant difference in UCG or MRI findings between the two groups. Low mismatch score in cardiac scintigraphy was the only predictive factor of cardiac failure or death by multivariate analysis (odds ratio, 6.48; 95% confidence interval, 1.22-423.2; P = 0.01). When patients were grouped according to high or low mismatch scores based on a cut-off using receiver operating characteristics curve analysis, the cumulative incidence of cardiac failure or death was higher in the low mismatch group than in the high mismatch group (P = 0.02). The percentage of fibrosis was significantly higher in deceased cases compared to surviving cases. CONCLUSIONS: Low mismatch score in cardiac scintigraphy was associated with cardiac death or cardiac failure in SSc patients.

The Association Between Bronchial Wall CT Attenuation and Spirometry in Patients with Bronchial Asthma.

RATIONALE AND OBJECTIVE: The purpose of this study was to evaluate the correlation between generation-based bronchial wall attenuation on thin-section computed tomography (CT) scans and airflow limitation in patients with bronchial asthma. MATERIALS AND METHODS: This study included 28 bronchial asthma patients (13 men, 15 women; age range, 23-89 years) who underwent both chest CT and spirometry. On CT, the mean values of peak wall attenuation, wall area percentage, and luminal area were measured in the segmental, subsegmental, and sub-subsegmental bronchi of the right B1 and B10 bronchi. Correlations of the CT measurements with forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC), percent predicted forced expiratory flow at 25%-75% of the FVC (%pred forced expiratory flow25-75), and percent predicted peak flow rate were evaluated with Spearman's rank correlation test. RESULTS: The peak wall attenuation of each generation of segmental bronchi significantly correlated with the forced expiratory volume in 1 second/FVC (B1 segmental, ρ = -0.683, p < 0.0001; B1 subsegmental, ρ = -0.875, p < 0.0001; B1 sub-subsegmental, ρ = -0.926, p < 0.0001; B10 segmental, ρ = -0.811, p < 0.0001; B10 subsegmental, ρ = -0.903, p < 0.0001; B10 sub-subsegmental ρ = -0.950, p < 0.0001). Similar correlations were found between the peak wall attenuation and %pred forced expiratory flow 25-75 or percent predicted peak flow rate. Overall, the correlation coefficients were relatively high in the more peripheral bronchial generations. In all measurements, the coefficients of the peak wall attenuations were higher than those of the wall area percentage and luminal area. CONCLUSION: Peak attenuation of the bronchial wall, particularly in the peripheral bronchi, measured on CT is a good biomarker for the severity of bronchial asthma.

Three-dimensional computed tomographic angiography with computed tomographic colonography for laparoscopic colorectal surgery.

PURPOSE: To prospectively correlate the preoperative vessel anatomy in three-dimensional computed tomographic angiography with computed tomographic colonography (3D-CTA with CTC) with that in laparoscopic surgery for colorectal cancer. METHODS: The study protocol was approved by our institutional review board. The study population consisted of 101 patients with colon cancer who underwent 3D-CTA with CTC between June 2016 and January 2018. Two radiologists assessed the branching patterns of sigmoid arteries (SAs) and right colonic artery (RCA), the position between the ileocolic artery (ICA) and superior mesenteric vein (SMV), and the existence of an accessory middle colonic artery (aMCA). The vessel anatomy on 3D-CTA with CTC was correlated with that of intraoperative findings. RESULTS: Ninety-eight examinations (97.0%) were technically successful. Between preoperative and intraoperative vessel anatomy, the branching patterns of SAs were concordant in all 29 cases with rectosigmoid and descending colon cancer. The branching patterns of RCA and the position between the ICA and SMV were completely concordant in 32 cases of cecal and ascending colon cancer. No aMCA was identified either intraoperatively or by imaging analysis. CONCLUSIONS: 3D-CTA with CTC guided the surgeons to determine the resection margin of the relevant vessels for laparoscopic colorectal surgery.

Early and Mid-Term Results of Endovascular Aortic Repair Using a Crossed-Limb Technique for Patients with Severely Splayed Iliac Angulation.

Objective: We evaluated early and mid-term results of endovascular aortic repair (EVAR) using crossed-limb and non-crossed-limb techniques. Material and Methods: From December 2011 to October 2013, 37 patients (31 men; mean age 75.4 years) were treated with EVAR (crossed-limb, 21 and non-crossed-limb, 16). We compared technical success, maximum short-axis diameter of abdominal aortic aneurysm, iliac angulation, time for catheterization of the short contralateral limb gate of the main body (SCT), and complications between the groups. Results: The mean follow-up period was 810±230 days. The technical success rate was 100%. There was no significant difference between the groups in terms of mean short-axis diameter. Iliac angulation was significantly wider in the crossed-limb group (53.3±14.6 vs. 39.4±13.0, p=0.0049). There was no significant difference between the groups in terms of SCT. Limb occlusion occurred in two cases (one crossed-limb and one non-crossed-limb). There were no aneurysm-related deaths. Conclusion: There were no differences between the crossed-limb and non-crossed-limb techniques in terms of early and mid-term results of EVAR. A crossed-limb technique can be performed safely without prolonged SCT even in severely splayed iliac angulation cases.

Correction to: Global and Japanese regional variations in radiologist potential workload for computed tomography and magnetic resonance imaging examinations.

In Results of Abstract, the first sentence should read as: The radiologist potential workload in Japan was 2.78-4.17 times higher than those in other countries.

Selective venous sampling supports localization of adenoma in primary hyperparathyroidism.

BACKGROUND: Selective venous sampling (SVS) is an invasive localization study for persistent or recurrent hyperparathyroidism. PURPOSE: To assess the role of SVS in addition to non-invasive imaging for primary hyperparathyroidism (pHPT). MATERIAL AND METHODS: This study was approved by the institutional review board and included 14 patients who underwent SVS and subsequent parathyroidectomy between January 2014 and April 2017 following a clinical diagnosis of pHPT. All patients underwent pre-SVS non-invasive imaging, including ultrasound, computed tomography (CT), and 99mTc-MIBI scintigraphy, and sensitivity was assessed using the operative and pathological findings. RESULTS: In all but one case, a single parathyroid adenoma was responsible for the pHPT; the remaining case exhibited a chemical response following surgical removal of parathyroid tissue. The sensitivity (%) for ultrasound, CT, 99mTc-MIBI scintigraphy, and SVS was 76.9, 84.6, 69.2, and 76.9, respectively. SVS yielded positive results in four patients with discordant results and one patient with non-detectable results on imaging. In seven patients, a significant increase in the intact parathyroid hormone level was recognized only in the thyroid veins. The procedure time was in the range of 52-183 min (median = 89.5 min). CONCLUSION: The addition of SVS to a non-invasive imaging study would be helpful to locate the responsible lesion of pHPT with discordant or non-detectable results on imaging for initial surgical treatment as well.

Factors associated with pericolic fat stranding of colon cancer on computed tomography colonography.

BACKGROUND: Pericolic fat stranding on computed tomography (CT) scans has been an important feature for staging colon cancer. However, the factors associated with pericolic fat stranding have not been elucidated to date. PURPOSE: To determine factors associated with pericolic fat stranding of colon cancer on CT colonography (CTC). MATERIAL AND METHODS: Overall, 150 patients with 155 colon cancer lesions were retrospectively assessed by two radiologists for pericolic fat stranding on CTC. Circumferential proportion of the tumor (CPtumor; <50%, 50-75%, and ≥75%), longitudinal length, depth of invasion (≤T2, T3, T4), lymph node and distant metastasis, and lymphovascular invasion were recorded. Univariate and multivariate logistic regression analyses were performed between pericolic fat stranding and each factor. Multi-group comparisons were performed for the CPtumor and depth of invasion. RESULTS: Pericolic fat stranding was identified in 57 lesions (36.8%). Univariate analysis revealed significant associations of pericolic fat stranding with all factors (P < 0.027), except for lymph node metastasis (P = 0.087). Multi-group comparisons revealed that pericolic fat stranding was more frequent with increasing CPtumor (P < 0.001); however, no significant differences were observed beyond subserosal infiltration (P = 0.225). Logistic regression analysis revealed the CPtumor (<75% vs. ≥75%; P = 0.008, <50% vs. 50-75%; P = 0.047) and longitudinal length (P = 0.001) as explainable variables. CONCLUSION: Pericolic fat stranding identified on CT images of colon cancer is demonstrated more frequently with increasing circumferential proportion of the tumor and longitudinal length.

Comparison of detectability of breast cancer by abbreviated breast MRI based on diffusion-weighted images and postcontrast MRI.

PURPOSE: To compare the detectability of unenhanced abbreviated magnetic resonance imaging (MRI) based on diffusion-weighted imaging (DWI) and abbreviated postcontrast MRI for breast cancer. METHODS: The study population consisted of 87 patients undergoing breast MRI between December 2016 and March 2017 in a clinical setting. All breast MRIs were performed using a 1.5-T MRI scanner with a 16-channel breast radiofrequency coil. The abbreviated protocols based on DWI (AP1) and postcontrast MRI (AP2) were assessed independently by two radiologists. Sensitivity and specificity were calculated. Receiver operating characteristic analysis was performed and the areas under the curves (AUCs) were compared between AP1 and AP2. RESULTS: The study included 87 patients with 89 breast cancer lesions ≤ 2 cm in diameter. The sensitivity/specificity for AP1 and AP2 for reader 1 was 89.9/97.6% and 95.5/90.6%, respectively, and those for reader 2 was 95.5/94.1% and 98.9/94.1%, respectively. The AUCs for AP1 and AP2 for reader 1 were 0.9629 and 0.9640 (p = 0.95), respectively, and those for reader 2 were 0.9755 and 0.9843 (p = 0.46), respectively. CONCLUSIONS: The detectability of the unenhanced abbreviated protocol based on DWI would be comparable to that of abbreviated postcontrast MRI for breast cancer.

Global and Japanese regional variations in radiologist potential workload for computed tomography and magnetic resonance imaging examinations.

PURPOSE: To investigate the global variation in radiologist potential workload for CT and MRI examinations, and the regional variation in potential workload and extent of radiologists' involvement in CT and MRI examinations in Japan. METHODS: "Radiologist potential workload" was defined as the annual number of CT plus MRI examinations divided by the total number of diagnostic radiologists. The extent of radiologists' involvement was measured as the proportion of CT and MRI examinations to which "Added-fees for Radiological Managements on Imaging-studies (ARMIs)" were applied among eligible examinations. Maximum variation was computed as the ratio of the highest-to-lowest values among the countries or Japanese prefectures. RESULTS: The radiologist potential workload in Japan was 2.78-4.17 times higher than those in other countries. A maximum prefecture-to-prefecture variation was 3.88. The average percentage of CT plus MRI examinations with ARMI applied was 43.3%, with a maximum prefecture-to-prefecture variation of 3.97. Prefectures with more radiologists tended to have a higher extent of radiologists' involvement. CONCLUSIONS: Japan had a far greater radiologist potential workload compared with other countries, with a large regional variation among prefectures. Prefectures with more radiologists tended to have a higher extent of radiologists' involvement in CT and MRI examinations.

Quantitative CT Evaluation of Small Pulmonary Vessels in Patients with Acute Pulmonary Embolism.

RATIONALE AND OBJECTIVES: The objective of this study was to investigate the correlation between the computed tomography (CT) cross-sectional area (CSA) of small pulmonary vessels and the CT obstruction index in patients with acute pulmonary embolism (PE) and the correlation between the changes in these measurements after anticoagulant therapy. MATERIALS AND METHODS: Fifty-two patients with acute PE were selected for this study. We measured the CSA less than 5 mm2 on coronal reconstructed images to obtain the percentage of the CSA (%CSA < 5). CT angiographic index was obtained based on the Qanadli method for the evaluation of the degree of pulmonary arterial obstruction. Spearman rank correlation analysis was used to evaluate the relationship between the initial and the follow-up values and changes in the %CSA < 5 and the CT obstruction index. RESULTS: There was no significant correlation between the %CSA < 5 and CT obstruction index on both initial (ρ = -0.03, P = 0.84) and follow-up (ρ = -0.03, P = 0.82) assessments. In contrast, there was a significant negative correlation between the changes in %CSA < 5 and the CT obstruction index (ρ = -0.59, P < 0.0001). CONCLUSIONS: Although the absolute %CSA < 5 and CT obstruction index were not significantly correlated, the changes in the values of the two parameters had a significant correlation. Changes in %CSA < 5, which can be obtained easily, can be used as biomarker of therapeutic response in patients with acute PE.