A novel use of CT attenuation value: increased bone marrow density in patients with acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. Bone marrow computed tomography (CT) attenuation may increase in patients with myeloproliferative disorders; however, the actual threshold CT attenuation value predictive of myeloproliferative has not been reported. PURPOSE: To determine whether the unenhanced CT attenuation value of the bone marrow may be useful for predicting AML. MATERIAL AND METHODS: We retrospectively analyzed patients with AML (n = 56) who underwent unenhanced CT before treatment, and age- and sex-matched controls without any hematologic disease. For each patient, the CT attenuation value (HU) of the iliac bone was measured and compared between the two groups. Receiver operating characteristic (ROC) curve analysis was used to define the cutoff value for predicting AML on all patients, and only on late elderly patients (aged ≥75 years). RESULTS: Patients with AML showed higher bone marrow CT attenuation value (131.4 ± 58.3 vs. 53.9 ± 67.2 HU; P < 0.001), compared to the controls. The sensitivity and specificity for the diagnosis of AML in all patients were 78.6% and 80.4%, respectively, at a threshold value of 90 HU, whereas they were 83.3% and 91.7%, respectively, at 40 HU in late elderly patients. CONCLUSION: The iliac bone CT attenuation value was elevated in patients with AML and may be useful for predicting AML.

Synthetic double inversion recovery imaging in brain MRI: quantitative evaluation and feasibility of synthetic MRI and a comparison with conventional double inversion recovery and fluid-attenuated inversion recovery sequences.

BACKGROUND AND PURPOSE: Synthetic MR imaging (SyMRI) allows the reconstruction of various contrast images, including double inversion recovery (DIR), from a single scan. This study aimed to investigate the advantages of SyMRI by comparing synthetic DIR images with synthetic T2-weighted fluid-attenuated inversion recovery (T2W-FLAIR) and conventional DIR images. MATERIALS AND METHODS: We retrospectively reviewed the imaging data of 100 consecutive patients who underwent brain MRI between December 2018 and March 2019. Synthetic DIR, T2W-FLAIR, T1-weighted, and phase-sensitive inversion recovery (PSIR) images were generated from SyMRI data. For synthetic DIR, the two inversion times required to suppress white matter and cerebrospinal fluid (CSF) were manually determined by two radiologists. Quantitative analysis was performed by manually tracing the region of interest (ROI) at the sites of the lesion, white matter, and CSF. Synthetic DIR, synthetic T2W-FLAIR, and conventional DIR images were compared on the basis of using the gray matter-to-white matter, lesion-to-white matter, and lesion-to-CSF contrast-to-noise ratios. RESULTS: The two radiologists showed no differences in setting inversion time (TI) values, and their evaluations showed excellent interobserver agreement. The mean signal intensities obtained with synthetic DIR were significantly higher than those obtained with synthetic T2W-FLAIR and conventional DIR. CONCLUSION: Synthetic DIR images showed a higher contrast than synthetic T2WFLAIR and conventional DIR images.

Anthropogenic gadolinium in the Tone River (Japan): an update showing a 7.7-fold increase from 1996 to 2020.

BACKGROUND: Anthropogenic gadolinium (Gd), originating from Gd-based contrast agents (GBCAs) used in magnetic resonance imaging (MRI), is widely identified in the aquatic environment with concerns about toxicity and accumulation. We aimed to present new data on anthropogenic Gd in the Tone River, which has the largest drainage area in Japan, and then to compare the current data with those obtained in 1996. METHODS: The water samples were collected on August 9-10, 2020, at 15 different locations of the Tone River in Japan. The concentrations of the rare earth elements (REEs) were measured by inductively coupled plasma-mass spectrometry and normalized to Post-Archean Australian Shale to construct shale-normalized REE patterns. The degree of Gd-anomaly was defined as the percentage of anthropogenic Gd to the geogenic background and used to compare the water samples from different locations. Pearson's correlation coefficients were calculated. RESULTS: All the samples displayed positive Gd anomalies. The Gd-anomaly ranged from 121 to 6,545% and displayed a repeating decrease-and-increase trend. The Gd-anomaly showed strong positive correlations to the number of hospitals (r = 0.88; p < 0.001) and their MRI units (r = 0.89; p < 0.001). CONCLUSIONS: Our study revealed notable anomalies of Gd concentrations in river water in Japan, with strong positive correlations to the number of major hospitals and their MRI units. Compared with the previous report in 2000, the Gd-anomaly in Tone River increased from 851% (sampled in 1996) to 6,545%, i.e., 7.7 times, reflecting the increased use of GBCAs in hospitals. RELEVANCE STATEMENT: Notable Gd concentration anomalies in river water in Japan were observed. This result underlines the importance of more extensive research on anthropogenic gadolinium, and investigations of risks to human health as well as the development of effective removal technologies may be necessary. KEY POINTS: • All water samples from Tone River displayed positive Gd anomalies. • The Gd anomalies increased to 7.7 times higher over the past 24 years. • Correlations between Gd values and the number of hospitals and MRI units were observed.

Predictive value of prostate calcification for future cancer occurrence: a retrospective long-term follow-up cohort study.

OBJECTIVE: Although prostate calcification is often identified on pelvic CT images, calcification itself is usually not considered clinically significant. A recent histological study proposed an association between prostate calcification and prostate cancer occurrence. Our aim was to determine the predictive value of prostate calcifications for future prostate cancer occurrence. METHODS: We retrospectively analysed male patients (≥50 years old) without prior prostate cancer history, who underwent unenhanced pelvic CT between April 2010 and March 2011, and followed-up until December 2021. Cox proportional hazards models were used to assess prostate cancer risk with prostate calcification (defined as a high-density area larger than 3 mm with CT attenuation values ≥ 130 HU), controlling for age, body mass index (BMI), hypertension and diabetes mellitus. RESULTS: A total of 636 male patients (mean age, 68 years ± 9 [standard deviation]) were evaluated. At the end of follow-up, prostate cancer had been more frequently diagnosed in patients with prostate calcification than those without prostate calcification (6.5% vs 2.6%). Multivariate analysis revealed that prostate calcification on CT was a significant predictor of future prostate cancer occurrence (hazard ratio [HR], 2.7; 95% CI: 1.20, 5.91; p = 0.016). No statistical differences were observed in any other factors. CONCLUSION: Prostate calcification may be a significant predictor of future prostate cancer occurrence, and may be used for risk stratification and to guide screening protocols. ADVANCES IN KNOWLEDGE: Presence of prostate calcification on unenhanced CT scan was associated with increased incidence of prostate cancer occurrence on long term follow-up.

Diagnostic value of "hyperdense consolidation sign" as a characteristic new computed tomography sign of diffuse alveolar hemorrhage.

Diffuse alveolar hemorrhage (DAH) is an uncommon but life-threatening condition. Although DAH must be distinguished from other lung diseases, no specific computed tomography (CT) signs of DAH have been reported. This study aimed to evaluate the diagnostic value of "hyperdense consolidation" CT sign. We retrospectively evaluated non-contrast CT findings of 25 DAH patients and age- (≤ 2 years) and sex-matched controls with symptoms of dyspnea and hypoxemia. Two radiologists compared the two groups for the presence of hyperdense consolidation signs in lung parenchyma, defined as consolidation that visually contains areas with higher density than the aorta in the specific narrow window setting (window level = 35 Hounsfield units [HU], width = 80 HU) with a mediastinal filter. The sensitivity, specificity, positive- and negative-predictive values of the hyperdense consolidation sign for detection of DAH were 32.0%, 100%, 100%, and 59.5% with perfect interobserver agreement (к = 1.00). The hyperdense consolidation sign was found to be a highly specific sign for DAH.

Whole-body magnetic resonance imaging (WB-MRI) with diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) in prostate cancer: Prevalence and clinical significance of incidental findings.

OBJECTIVE: Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) is now recommended as a first-line staging modality in prostate cancer patients, and the widespread use of DWIBS may lead to an increased frequency of incidental findings. The aim of this study was to evaluate the prevalence and clinical significance of incidental findings on whole-body magnetic resonance imaging (WB-MRI) with DWIBS. METHODS: Data from 124 patients with prostate cancer (age, 76.5 ± 5.6 years), who underwent 1.5 T WB-MRI with STIR, TSE-T2, TSE-T1, In/Out GRE, and DWIBS sequences, were retrospectively analyzed. Findings unrelated to prostate cancer were considered as incidental findings and categorized into two groups based on their clinical implications as follows: imaging follow-up or additional examinations was required (significant incidental findings) and no need to additional work-up (non-significant incidental findings). A chi-square test was performed to compare the differences in the prevalence of significant incidental findings based on age (≤75 and>75 years old). RESULTS: A total of 334 incidental findings were found with 8.1% (n = 27) as significant incidental findings. Significant incidental findings were more frequent in patients over 75 years old than those of 75 years old or younger (28.6% vs 11.1%, p = 0.018). CONCLUSION: Clinically significant incidental findings, which required imaging follow-up or additional examinations, were commonly observed in prostate cancer patients on WB-MRI/DWIBS. ADVANCES IN KNOWLEDGE: Some incidental findings were clinically significant that may lead to changes in treatment strategy. Checking the entire organ carefully for abnormalities and reporting any incidental findings detected are important.

Effect of type 2 diabetes on Gd-EOB-DTPA uptake into liver parenchyma: replication study in human subjects.

PURPOSE: Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) is a contrast agent for magnetic resonance imaging (MRI), which specifically taken up by hepatocytes through organic anion-transporting polypeptides (OATPs). Previous research in mice has shown that type 2 diabetes is associated with reduced uptake of Gd-EOB-DTPA into the liver parenchyma, reflecting reduced expression of OATP. Since considerable differences in OATP expression exist between mice and humans, human studies are necessary to clarify the effect of diabetes to Gd-EOB-DTPA uptake. The purpose of this study was to validate the effect of diabetes to Gd-EOB-DTPA liver uptake by a confirmatory study in humans. METHODS: Patients who underwent Gd-EOB-DTPA-enhanced MRI were retrospectively reviewed and divided into two groups: severe or uncontrolled diabetic group (patients with insulin therapy and/or HbA1c ≥ 8.4%) and the control group. Liver-to-spleen ratio (LSR) and relative enhancement of the liver (REL) were calculated to represent Gd-EOB-DTPA liver uptake. RESULTS: A total of 94 patients fulfilled the criteria. The severe or uncontrolled diabetic group (n = 15) showed significantly lower LSR (1.74 ± 0.26 vs. 1.98 ± 0.31, p = 0.007) and REL (0.69 ± 0.23 vs. 0.87 ± 0.31, p = 0.005), compared to the control group (n = 79). CONCLUSION: Our study revealed decreased uptake of Gd-EOB-DTPA into liver parenchyma in the severe or uncontrolled diabetic patients. Further studies to determine the impact of the reduced liver enhancement on clinical diagnostic practice will be needed.