Diffusion-derived vessel density (DDVD) computed from a simple diffusion MRI protocol as a biomarker of placental blood circulation in patients with placenta accreta spectrum disorders: A proof-of-concept study

OBJECTIVES

Increasing trend of PAS (placenta accreta spectrum disorders) incidence is a major health concern as PAS is associated with high maternal morbidity and mortality during cesarean section. Prenatal identification of PAS is crucial for delivery planning and patients management. This study aims to explore whether diffusion-derived vessel density (DDVD) computed from a simple diffusion MRI protocol differs in PAS from normal placenta.

METHODS

We enrolled 86 patients with PAS disorders and 40 pregnant women without PAS disorders. Each patient underwent intravoxel incoherent motion (IVIM) MRI sequence with 11 b-values. Placenta diffusion-derived vessel density (DDVD-b0b50) was the signal difference between b = 0 and b = 50 s/mm2 images. DDVD(b0b50) A/N was calculated as [accreta lesion DDVD(b0b50)]/ [normal placenta DDVD(b0b50)]. The correlation between DDVD and gestational age was explored using Spearman rank correlation. Differences of DDVD(b0b50) A/N in patients with normal placentas and with PAS, and in patients with different subtypes of PAS were explored.

RESULTS

DDVD was negatively correlated with gestational age (p = 0.023, r = -0.359) in patients with normal placentas. DDVD(b0b50) A/N was significantly higher in patients with PAS (median:1.16, mean: 1.261) than normal placenta (median:1.02, mean: 1.032, p < 0.001) and especially higher in patients with placenta increta (median:1.14, mean: 1.278) and percreta (median: 1.20, mean: 1.396, p < 0.001).

CONCLUSION

As a higher DDVD indicates higher physiological volume of micro-vessels in PAS, this study suggests DDVD can be a potential biomarker to evaluate the placenta perfusion.

Perfusion of hepatocellular carcinomas measured by diffusion-derived vessel density biomarker: Higher hepatocellular carcinoma perfusion than earlier intravoxel incoherent motion reports

Diffusion-derived vessel density (DVDD) is a physiological surrogate of the area of microvessels per unit tissue area. DDVD is calculated according to DDVD(b0b2) = Sb0/ROIarea0 - Sb2/ROIarea2, where Sb0 and Sb2 refer to the liver signal when b is 0 or 2 s/mm2. Pathohistological studies and contrast-enhanced CT/MRI data showed higher blood volume in hepatocellular carcinoma (HCC) relative to native liver tissue. With intravoxel incoherent motion (IVIM) imaging, most authors paradoxically reported a decreased perfusion fraction of HCC relative to the adjacent liver. This study applied DDVD to assess the perfusion of HCC. MRI was performed with a 3.0-T magnet. Diffusion-weighted images with b-values of 0 and 2 s/mm2 were acquired in 72 HCC patients. Thirty-two patients had microvascular invasion (MVI(+)) and 40 patients did not have microvascular invasion (MVI(-)). Fifty-eight patients had Edmondson-Steiner grade I or II HCC, and 14 patients had Edmondson-Steiner grade III or IV HCC. DDVD measurement was conducted on the axial slice that showed the largest HCC size. DDVD(b0b2) T/L = HCC DDVD(b0b2)/liver DDVD(b0b2). DDVD(b0b2) T/L median (95% confidence interval) of all HCCs was 2.942 (2.419-3.522), of MVI(-) HCCs was 2.699 (2.030-3.522), of MVI(+) HCCs was 2.988 (2.423-3.990), of Edmondson-Steiner grade I/II HCCs was 2.873 (2.277-3.465), and of Edmondson-Steiner grade III/IV HCCs was 3.403 (2.008-4.485). DDVD(b0b2) T/L approximately agrees with contrast agent dynamically enhanced CT/MRI literature data, whereas it differs from earlier IVIM study results, where HCC perfusion fraction was paradoxically lower relative to native liver tissue. A weak trend was noted with MIV(+) HCCs had a higher DDVD(b0b2) T/L than that of MVI(-) HCCs, and a weak trend was noted with the poorly differentiated group of HCCs (Edmondson-Steiner grade III and IV) had a higher DDVD(b0b2) T/L than that of the better differentiated group of HCCs (Edmondson-Steiner grade I and II).

Higher perfusion of rectum carcinoma relative to tumor-free rectal wall: quantification by a new imaging biomarker diffusion-derived vessel density (DDVD)

Background

Diffusion-derived vessel density (DDVD) is a physiological surrogate of the area of micro-vessels per unit tissue area. DDVD is calculated according to: DDVD(b0b5) = Sb0/ROIarea0 - Sb5/ROIarea5, where Sb0 and Sb5 refer to the tissue signal when b is 0 or 5 s/mm2. This study applied DDVD to assess the perfusion of rectal carcinoma (RC).

Methods

MRI was performed with a 3.0-T magnet. Diffusion weighted image with b-values of 0, 5 s/mm2 were acquired in 113 patients with non-mucinous RC and 15 patients with mucinous RC. Diffusion-derived vessel density ratio [DDVDr(b0b5)] was DDVD(b0b5) of RC divided by DDVD(b0b5) of tumor-free rectal wall.

Results

The median value of the DDVDr(b0b5) for non-mucinous RCs was 1.430, with the majority of RCs showing a higher DDVD than the adjacent tumor-free wall [i.e., with DDVDr(b0b5) >1]. 90.3% (102/113) of non-mucinous RCs were hypervascular, 1.77% (2/113) were iso-vascular, and 7.96% (9/113) were hypovascular. The median value of the DDVDr(b0b5) for mucinous RCs was 1.660. 73.3% (11/15) of mucinous RCs were hypervascular, and 26.7% (4/15) were hypovascular. A trend (P=0.09) was noted that earlier clinical grades non-mucinous RCs had a higher DDVDr(b0b5) than those of the advanced clinical grades (2.245 for grade 0&I, 1.460 for grade II, 1.430 for grade III, 1.130 for grade IV). A non-significant trend was noted with well and moderately differentiated non-mucinous RCs had a higher DDVDr(b0b5)than that of poorly differentiated non-mucinous RCs (median: 1.460 vs. 1.320). A non-significant trend was noted with MRI-detected extramural vascular invasion (mrEMVI) positive non-mucinous RCs had a higher DDVDr(b0b5) than that of mrEMVI negative non-mucinous RCs (1.630 vs. 1.370).

Conclusions

DDVD results in this study approximately agree with contrast agent dynamically enhanced CT literature data.

Radiological diagnosis of prevalent osteoporotic vertebral fracture on radiographs: an interim consensus from a group of experts of the ESSR osteoporosis and metabolism subcommittee

When a low-energy trauma induces an acute vertebral fracture (VF) with clinical symptoms, a definitive diagnosis of osteoporotic vertebral fracture (OVF) can be made. Beyond that, a "gold" radiographic standard to distinguish osteoporotic from non-osteoporotic VFs does not exist. Fracture-shaped vertebral deformity (FSVD) is defined as a deformity radiographically indistinguishable from vertebral fracture according to the best of the reading radiologist's knowledge. FSVD is not uncommon among young populations with normal bone strength. FSVD among an older population is called osteoporotic-like vertebral fracture (OLVF) when the FSVD is likely to be associated with compromised bone strength. In more severe grade deformities or when a vertebra is collapsed, OVF diagnosis can be made with a relatively high degree of certainty by experienced readers. In "milder" cases, OVF is often diagnosed based on a high probability rather than an absolute diagnosis. After excluding known mimickers, singular vertebral wedging in older women is statistically most likely an OLVF. For older women, three non-adjacent minimal grade OLVF (< 20% height loss), one minimal grade OLVF and one mild OLVF (20-25% height loss), or one OLVF with ≥ 25% height loss, meet the diagnosis of osteoporosis. For older men, a single OLVF with < 40% height loss may be insufficient to suggest the subject is osteoporotic. Common OLVF differential diagnoses include X-ray projection artifacts and scoliosis, acquired and developmental short vertebrae, osteoarthritic wedging, oncological deformities, deformity due to high-energy trauma VF, lateral hyperosteogeny of a vertebral body, Cupid's bow, and expansive endplate, among others.

Repeatability and reproducibility comparisons of liver IVIM imaging with free-breathing or respiratory-triggered sequences

For liver intravoxel incoherent motion (IVIM) data acquisition, respiratory-triggering (RT) MRI is commonly used, and there are strong motivations to shorten the scan duration. For the same scan duration, more b values or higher numbers of excitations can be allowed for free-breathing (FB) imaging than for RT. We studied whether FB can be used to replace RT when careful IVIM image acquisition and image processing are conducted. MRI data of 22 healthy participants were acquired using a 3.0 T scanner. Diffusion imaging was based on a single-shot spin-echo-type echo-planar sequence and 16 b values of 0, 2, 4, 7, 10, 15, 20, 30, 46, 60, 72, 100, 150, 200, 400, and 600 s/mm2 . Each subject attended two scan sessions with an interval of 10-20 days. For each scan session, a subject was scanned twice, first with RT and then with FB. The mean image acquisition time was 5.4 min for FB and 10.8 min for RT. IVIM parameters were calculated with bi-exponential model segmented fitting with a threshold b value of 60 s/mm2 , and fitting started from b = 2 s/mm2 . There was no statistically significant difference between IVIM parameters measured with FB imaging or RT imaging. Perfusion fraction ICC (intraclass correlation coefficient) for FB imaging and RT imaging in the same scan session was 0.824. For perfusion fraction, wSD (within-subject standard deviation), BA (Bland-Altman) difference, BA 95% limit, and ICC were 0.022, 0.0001, -0.0635~0.0637, and 0.687 for FB and 0.031, 0.0122, -0.0723~0.0967, and 0.611 for RT. For Dslow (×10-3  s/mm2 ), wSD, BA difference, BA 95% limit, and ICC were 0.057, 0.0268, -0.1258~0.1793, and 0.471 for FB and 0.073, -0.0078, -0.2170-0.2014, and <0.4 for RT. The Dfast coefficient of variation was 0.20 for FB imaging and 0.28 for RT imaging. All reproducibility indicators slightly favored FB imaging.

Quantitative CT lumbar spine BMD cutpoint value for classifying osteoporosis among older East Asian women should be lower than the value for Caucasians

For Caucasian women, the QCT (quantitative CT) lumbar spine (LS) bone mineral density (BMD) cutpoint value for classifying osteoporosis is 80 mg/ml. At the age of approximate 78 years, US Caucasian women QCT LS BMD population mean is 80 mg/ml, while that of Chinese women and Japanese women is around 50 mg/ml. Correlation analyses show, for Chinese women and Japanese women, QCT LS BMD of 45 mg/ml corresponds to the dual-energy X-ray absorptiometry cutpoint value for classifying osteoporosis. For Chinese and Japanese women, if QCT LS BMD 80 mg/ml is used as the threshold to classify osteoporosis, then the specificity of classifying subjects with vertebral fragility fracture into the osteoporotic group is low, whereas threshold of 45 mg/ml approximately achieve a similar separation for women with and without vertebral fragility fracture as the reports for Caucasian women. Moreover, by using 80mg/ml as the cutpoint value, LS QCT leads to excessively high prevalence of osteoporosis for Chinese women, with the discordance between hip dual-energy X-ray absorptiometry and LS QCT measures far exceeding expectation. Considering the different bone properties and the much lower prevalence of fragility fractures in the East Asian women compared with Caucasians, we argue that the QCT cutpoint value for classifying osteoporosis among older East Asian women will be close to and no more than 50 mg/ml LS BMD. We suggest that it is also imperative the QCT osteoporosis classification criterion for East Asian male LS, and male and female hips be re-examined.

A novel automatic segmentation method directly based on magnetic resonance imaging K-space data for auxiliary diagnosis of glioma

Background

The use of segmentation architectures in medical imaging, particularly for glioma diagnosis, marks a significant advancement in the field. Traditional methods often rely on post-processed images; however, key details can be lost during the fast Fourier transformation (FFT) process. Given the limitations of these techniques, there is a growing interest in exploring more direct approaches. The adaption of segmentation architectures originally designed for road extraction for medical imaging represents an innovative step in this direction. By employing K-space data as the modal input, this method completely eliminates the information loss inherent in FFT, thereby potentially enhancing the precision and effectiveness of glioma diagnosis.

Methods

In the study, a novel architecture based on a deep-residual U-net was developed to accomplish the challenging task of automatically segmenting brain tumors from K-space data. Brain tumors from K-space data with different under-sampling rates were also segmented to verify the clinical application of our method.

Results

Compared to the benchmarks set in the 2018 Brain Tumor Segmentation (BraTS) Challenge, our proposed architecture had superior performance, achieving Dice scores of 0.8573, 0.8789, and 0.7765 for the whole tumor (WT), tumor core (TC), and enhanced tumor (ET) regions, respectively. The corresponding Hausdorff distances were 2.5649, 1.6146, and 2.7187 for the WT, TC, and ET regions, respectively. Notably, compared to traditional image-based approaches, the architecture also exhibited an improvement of approximately 10% in segmentation accuracy on the K-space data at different under-sampling rates.

Conclusions

These results show the superiority of our method compared to previous methods. The direct performance of lesion segmentation based on K-space data eliminates the time-consuming and tedious image reconstruction process, thus enabling the segmentation task to be accomplished more efficiently.

Differences in pulmonary nodular consolidation and pulmonary cavity among drug-sensitive, rifampicin-resistant and multi-drug resistant tuberculosis patients: the Guangzhou computerized tomography study

Background

Pulmonary nodular consolidation (PN) and pulmonary cavity (PC) may represent the two most promising imaging signs in differentiating multidrug-resistant (MDR)-pulmonary tuberculosis (PTB) from drug-sensitive (DS)-PTB. However, there have been concerns that literature described radiological feature differences between DS-PTB and MDR-PTB were confounded by that MDR-PTB cases tend to have a longer history. This study seeks to further clarify this point.

Methods

All cases were from the Guangzhou Chest Hospital, Guangzhou, China. We retrieved data of consecutive new MDR cases [n=46, inclusive of rifampicin-resistant (RR) cases] treated during the period of July 2020 and December 2021, and according to the electronic case archiving system records, the main PTB-related symptoms/signs history was ≤3 months till the first computed tomography (CT) scan in Guangzhou Chest Hospital was taken. To pair the MDR-PTB cases with assumed equal disease history length, we additionally retrieved data of 46 cases of DS-PTB patients. Twenty-two of the DS patients and 30 of the MDR patients were from rural communities. The first CT in Guangzhou Chest Hospital was analysed in this study. When the CT was taken, most cases had anti-TB drug treatment for less than 2 weeks, and none had been treated for more than 3 weeks.

Results

Apparent CT signs associated with chronicity were noted in 10 cases in the DS group (10/46) and 9 cases in the MDR group (10/46). Thus, the overall disease history would have been longer than the assumed <3 months. Still, the history length difference between DS patients and MDR patients in the current study might not be substantial. The lung volume involvement was 11.3%±8.3% for DS cases and 8.4%±6.6% for MDR cases (P=0.022). There was no statistical difference between DS cases and MDR cases both in PN prevalence and in PC prevalence. For positive cases, MDR cases had more PN number (mean of positive cases: 2.63 vs. 2.28, P=0.38) and PC number (mean of positive cases: 2.14 vs. 1.38, P=0.001) than DS cases. Receiver operating characteristic curve analysis shows, PN ≥4 and PC ≥3 had a specificity of 86% (sensitivity 25%) and 93% (sensitivity 36%), respectively, in suggesting the patient being a MDR cases.

Conclusions

A combination of PN and PC features allows statistical separation of DS and MDR cases.

Diffusion-Derived Vessel Density Computed From a Simplified Intravoxel Incoherent Motion Imaging Protocol in Pregnancies Complicated by Early Preeclampsia: A Novel Biomarker of Placental Dysfunction

BACKGROUND

Early preeclampsia is associated with significant placental hypoperfusion. We explore the diagnostic value of placental diffusion-derived vessel density, a biomarker derived from diffusion-weighted magnetic resonance imaging, which measures in vivo vessel microperfusion, in the differential diagnosis of normal and early preeclampsia pregnancies.

METHODS

This was a prospective study involving 29 controls and 17 singleton pregnancies affected by early preeclampsia. Nineteen pregnancies from 28 to 34 weeks of gestational age were included from the normal group for a comparison with the early preeclampsia group. Using a 3.0 T magnetic resonance imaging scanner, diffusion-weighted images were obtained with the diffusion weighting b values of 0, 20, and 40 s/mm². DDVD_mean was the mean of DDVD_b0b20 and DDVD_b0b40, while DDVD_b0b20 and DDVD_b0b40 refer to the diffusion-derived vessel density values computed from b=0 and 20 s/mm² images, and from b=0 and 40 s/mm² images, respectively. The correlation between DDVD_mean and gestational age was examined using a linear regression model. The area under the curve of the DDVD_mean for early preeclampsia pregnancies detection was calculated by the receiver operating characteristic analysis.

RESULTS

As gestational age increased, DDVD_mean linearly decreased. DDVD_mean was significantly decreased in the early preeclampsia pregnancies compared with the normal pregnancies (52.72±46.73 versus 213.34±93.50 au/pixel; P<0.001). The area under the curve (DDVD_mean) for discriminating between normal and early preeclampsia pregnancies regardless of fetal growth restriction was 0.954, and the area under the curve was 1.000 when early preeclampsia pregnancies without fetal growth restriction were excluded.

CONCLUSIONS

DDVD_mean, an in vivo vessel microperfusion measure, allowed total separation of normal and early preeclampsia pregnancies.

Schmorl's nodes are associated with prevalent osteoporotic vertebral fracture and low bone mineral density: a population-based thoracic spine MRI study in older men and women

Background

Schmorl's node (SN) corresponds to nucleus pulposus herniation into the vertebral spongy bone with thickened trabeculae around the formed node. We hypothesize that a pathway may exist that: osteoporosis → weakened endplate → SN development ↔ endplate fracture of an osteoporotic vertebra.

Methods

For osteoporotic fractures in men (MrOS) and in women (MsOS) Hong Kong studies, at 14-year follow-up, thoracic spine magnetic resonance imaging (MRI) was sampled in 270 males (mean: 82.9±3.7 years) and 150 females (mean: 81.5±4.3 years). SN and Modic change were assessed as existed or not existed. For posterior disc protrusion, ligamentum flavum ossification, and spinal canal stenosis, semi-quantitative gradings were applied. For each vertebra in women, a score of 0, 0.5, 1, 1.5, 2, 2.5, 3 was assigned for no osteoporotic vertebral fracture (OVF) or OVF of <1/5, ≥1/5-1/4, ≥1/4-1/3, ≥1/3-2/5, ≥2/5-2/3, and ≥2/3 vertebral height loss, respectively, and a summed score was calculated by summing up the scores of vertebrae T1 to T12. For men, those of minimal grade were not considered as OVF and assigned a '0' score.

Results

SN prevalence in women (55.5%) almost doubled that in men (25.9%). SN was statistically significantly correlated with lower bone mineral density (BMD) derived femoral neck T-score, while the other four spine degeneration changes were not statistically significantly correlated with the T-score. SN were statistically significantly correlated with OVF score. Subjects with SN were more likely to have OVF, with odds ratio for men of 4.32 [95% confidence interval (CI): 1.70-11.00, P=0.002] and odds ratio for women of 3.28 (95% CI: 1.23-8.74, P=0.018).

Conclusions

Among older population, many features of SN parallel those of OVF.

Conversion of osteoporotic-like vertebral fracture severity score to osteoporosis T-score equivalent status: A framework study for older Chinese men

Objectives

To define what portion of older community men with what severity of radiographic osteoporotic-like vertebral fracture (OLVF) correspond to what low T-score status.

Methods

There were 755 community Chinese men (age: 76.4 ± 6.7 years) with thoracic and lumbar spine radiographs, and hip and lumbar spine bone mineral density measures. For each vertebra in a subject, a score of 0, -0.5, -1, -1.5, -2, -2.5, and -3 was assigned for no OLVF or OLVF of <20%, ≥ 20-25%, ≥ 2 5%-1/3, ≥ 1/3-40%, ≥ 40%-2/3, and ≥ 2/3 vertebral height loss, respectively. OLVFss was defined as the summed score of vertebrae T4 to L5. OLVFss and T-scores were ranked from the smallest to the largest values.

Results

OLVFss of -2, -2.5, -3, corresponded to a mean femoral neck T-score of -2.297 (range: -2.355∼-2.247), -2.494 (range: -2.637∼ -2.363), and -2.773 (range: -2.898∼-2.643), a mean hip T-score of-2.311 (range: -2.420∼-2.234), -2.572 (range: -2.708∼-2.432), -2.911 (range: -3.134∼-2.708), a mean lumbar spine T-score of -2.495 (range: -2.656∼-2.403), -2.931 (range: -3.255∼-2.664), and -3.369 (range: -3.525∼-3.258). The Pearson correlation value of OLVFss and T-score of femoral neck, hip and lumbar spine was r = 0.21, 0.26, and 0.22 (all P < 0.0001).

Conclusions

A single severe grade radiological OLVF (≥ 40% height loss) or OLVFss ≤ -2.5 suggest the subject is osteoporotic, and a single collapse grade (≥ 2/3 height loss) OLVF or OLVFss ≤ -3 meets osteoporosis diagnosis criterion. The results highlight the difficulty of diagnosing osteoporotic vertebral fractures among Chinese older men.

Osteoporotic-like vertebral fracture with less than 20% height loss is associated with increased further vertebral fracture risk in older women: the MrOS and MsOS (Hong Kong) year-18 follow-up radiograph results

Background

For osteoporotic fractures in men (MrOS) and in women (MsOS) (Hong Kong) baseline (BL) study, Chinese men and women ≥65 years were recruited during 2001 to 2003. This study presents the year-18 follow-up (FU) results. We were particularly interested in whether women with 'minimal' grade osteoporotic-like vertebral fracture (OLVF) of <20% height loss have an increased vertebral fracture (VF) risk than those without BL OLVF.

Methods

At year-18 FU, spine radiography was performed on 144 males (mean: 87.4±3.1 years) and 156 females (mean: 87.0±3.2 years). OLVF classification included no OLVF (grade 0), and OLVFs with <20%, ≥20-25%, ≥25%-1/3, ≥1/3-40%, ≥40%-2/3, ≥2/3 height loss (grades 1-6). With an existing OLVF, a further height loss of ≥15% was an OLVF progression. A new incident OLVF was a change from grade 0 to ≥ grade 2 or to grade 1 with the appearance of endplate and/or cortex fracture (ECF) during FU. Both OLVF progression and incident OLVF were considered incident VF. Acquired short vertebra (aSV) was defined as with decreased vertebral anterior and middle heights, while without anterior wedging and bi-concave changes, and only those with at least two adjacent aSVs were recorded as aSV cases.

Results

For subjects without BL OLVF, 12.5% of the males and 27.1% of the females had incident VF. For subjects with BL OLVF of ≥20% height loss, males' and females' incident VF rate were 20% and 66.7% respectively. Females subjects with BL minimal OLVF, while all without radiographic ECF, had an incident VF rate of 59.3% during the FU. For males with and without aSV, 11.8% and 15% have incident fracture of other vertebrae. For females with and without aSV, 35.3% and 34.5% have incident fracture of other vertebrae. Recovery from minimal or mild grades OLVF to normal shape was observed in a number of cases.

Conclusions

OLVF with less than 20% height loss is associated with increased VF risk in older females, but not in older males. Acquired short vertebra (SV) is not associated with increased incident fracture risk for other vertebrae, both for females and males. OLVF among older subjects can repair and heal.

Deep learning attention-guided radiomics for COVID-19 chest radiograph classification

Background

Accurate assessment of coronavirus disease 2019 (COVID-19) lung involvement through chest radiograph plays an important role in effective management of the infection. This study aims to develop a two-step feature merging method to integrate image features from deep learning and radiomics to differentiate COVID-19, non-COVID-19 pneumonia and normal chest radiographs (CXR).

Methods

In this study, a deformable convolutional neural network (deformable CNN) was developed and used as a feature extractor to obtain 1,024-dimensional deep learning latent representation (DLR) features. Then 1,069-dimensional radiomics features were extracted from the region of interest (ROI) guided by deformable CNN's attention. The two feature sets were concatenated to generate a merged feature set for classification. For comparative experiments, the same process has been applied to the DLR-only feature set for verifying the effectiveness of feature concatenation.

Results

Using the merged feature set resulted in an overall average accuracy of 91.0% for three-class classification, representing a statistically significant improvement of 0.6% compared to the DLR-only classification. The recall and precision of classification into the COVID-19 class were 0.926 and 0.976, respectively. The feature merging method was shown to significantly improve the classification performance as compared to using only deep learning features, regardless of choice of classifier (P value <0.0001). Three classes' F1-score were 0.892, 0.890, and 0.950 correspondingly (i.e., normal, non-COVID-19 pneumonia, COVID-19).

Conclusions

A two-step COVID-19 classification framework integrating information from both DLR and radiomics features (guided by deep learning attention mechanism) has been developed. The proposed feature merging method has been shown to improve the performance of chest radiograph classification as compared to the case of using only deep learning features.

Conversion of osteoporotic vertebral fracture severity score to osteoporosis T-score equivalent status: a framework and a comparative study of Hong Kong Chinese and Rome Caucasian older women

We explored how the severity of radiological osteoporotic vertebral fracture (OVF) can be converted to the equivalent T-score values.

INTRODUCTION

To perform a study to define what portion of older community women with what severity of radiographic OVF correspond to what low T-score status.

METHODS

There were age-matched 301 Italian community women and 301 Chinese community women (sub-group A, age, 73.6 ± 6.1 years). In addition, Chinese sub-groups B and C included 110 community women (age, 68.9 ± 5.5 years) and 101 community women (age: 82.2 ± 4.3 years), respectively. For each vertebra in women, a score of 0, - 0.5, - 1, - 1.5, - 2, - 2.5, and - 3 was assigned for no OVF or OVF of < 20%, ≥ 20 ~ 25%, ≥ 25% ~ 1/3, ≥ 1/3 ~ 40%, ≥ 40%-2/3, and ≥ 2/3 vertebral height loss, respectively, OVFss was defined as the summed score of vertebrae T4 to L5. OVFss and T-scores were ranked from the smallest to the largest values.

RESULTS

For the Chinese total group (sub-groups A, B, and C together), OVFss = - 1 corresponded to lowest T-score (lowest T-score of lumbar spine, femoral neck, and total hip) of - 3.4 ~ - 3.2. OVFss ≤ - 1.5 corresponded to femoral neck T-score ≤ - 2.5. OVFss = -1.5 corresponded to a mean femoral neck T-score of - 3.0, - 2.6, and - 2.4, among Chinese sub-groups B, A, and C subjects, respectively. For Italians, all cases with OVFss ≤ - 1 had lowest T-score ≤ - 2.5. For cases with femoral neck T-score = - 2.5, 41.7% had OVFss = - 1.5, and 58.3% had OVFss = - 1.

CONCLUSION

For older women, statistically OVFss ≤ - 1 suggests this subject is osteoporotic according to lowest T-score. If using femoral neck T-score, OVFss ≤ - 1.5 qualifies osteoporosis diagnosis.

Chest radiograph prevalence of vertebral deformity among young and middle-aged population of mixed city dwellers and rural residents

Background

To interpret the importance of minimal and mild vertebral deformities (VDs) among elderly subjects, we need to know their prevalence among mostly non-osteoporotic subjects.

Methods

We retrospectively analyzed VDs among 408 female and 374 male patients who had lateral chest radiographs due to mild illness or for routine healthcheck, all with indications other than spine disorders or metabolic disorders. The study subjects were divided into four age groups, i.e., ≤20, 20-34, 35-44, and ≥45 years. For those aged >20 years, 27.2% females had family roots from farming communities, and 26.4% males had the history of being a farmer or physical laborer (this was 36.1% for males aged ≥45 years). Fracture shaped vertebral deformities (FSVDs) were VDs radiographically indistinguishable from vertebral fracture. Acquired short vertebrae were those with decreased vertebral anterior and middle heights, while without anterior wedging or bi-concave changes, and the diagnosis required at least two adjacent short vertebrae in the same subject.

Results

Congenital VDs were observed in four cases (three males, one female). In the age group of ≤20, 20-34, 35-44, and ≥45 years, females had any FSVD prevalence of 13.4%, 8.3%, 11.8%, 25.8% respectively, while the prevalence was 29.3%, 26%, 34.3%, 44.8% respectively for males. From the female ≤20 years group to the 21-34 years group, cases involved multiple vertebrae decreased from 53.8% to 16.7%. For cases ≤34 years, no female case had ≥ mild FSVD (which was defined to have ≥20% vertebral height loss), while five male cases had ≥ mild FSVD. For the 35-44 years group, vertebral endplate depression was noted among 2.0% of the females and 2.9% of the males. Among the cases aged ≤44 years, there was only one male and one female had acquired short vertebrae. For the male cases, acquired short vertebrae prevalence was 15.6% in the group of ≥45 years.

Conclusions

FSVD is common among young and middle-aged population (≤44 years) assumed with normal bone strength, and with a higher FSVD prevalence among men. FSVD may heal among younger subjects, and physical labor may increase VD prevalence.

Estimations of bone mineral density defined osteoporosis prevalence and cutpoint T-score for defining osteoporosis among older Chinese population: a framework based on relative fragility fracture risks

This study estimated the bone mineral density (BMD) defined osteoporosis prevalence of Chinese women and Chinese men aged ≥50 years. The estimation was based on the 1994 WHO definition of osteoporosis and two assumptions: (I) fragility fracture (FF) risk among older Chinese is half of that of older US Caucasians; (II) FF risk among older Chinese men is half of that of older Chinese women. In addition, we also consider the FF risk among older Chinese is close to those of American Blacks. We estimated that the osteoporosis prevalence based on lumbar BMD, femoral neck BMD, total hip BMD would be 15.8%, 20.4%, and 15.2% for US Caucasian women, 6.7%, 7.8%, and 7.9% for US black women, 7.5%, 7.5%, and 6.7% for Chinese women, 1.8%, 5.7%, and 3.3% for US black men, and 2.0%, 3.8%, and 3.4% for Chinese men. To satisfy the above estimates of osteoporosis prevalence for the Chinese population, in addition to using a local reference database, we suggest that the T-score cutpoints for defining osteopenia and osteoporosis among older Chinese should be adjusted from the conventional WHO thresholds of −2.5 and −1.0. Our suggested revised cutpoint T-score for defining osteoporosis described in this article will be more in line with the original WHO definition and will allow a more meaningful international comparison of disease burden.

A software program for automated compressive vertebral fracture detection on elderly women's lateral chest radiograph: Ofeye 1.0

Background

Because osteoporotic vertebral fracture (OVF) on chest radiographs is commonly missed in radiological reports, we aimed to develop a software program which offers automated detection of compressive vertebral fracture (CVF) on lateral chest radiographs, and which emphasizes CVF detection specificity with a low false positivity rate.

Methods

For model training, we retrieved 3,991 spine radiograph cases and 1,979 chest radiograph cases from 16 sources, with among them in total 1,404 cases had OVF. For model testing, we retrieved 542 chest radiograph cases and 162 spine radiograph cases from four independent clinics, with among them 215 cases had OVF. All cases were female subjects, and except for 31 training data cases which were spine trauma cases, all the remaining cases were post-menopausal women. Image data included DICOM (Digital Imaging and Communications in Medicine) format, hard film scanned PNG (Portable Network Graphics) format, DICOM exported PNG format, and PACS (Picture Archiving and Communication System) downloaded resolution reduced DICOM format. OVF classification included: minimal and mild grades with <20% or ≥20–25% vertebral height loss respectively, moderate grade with ≥25–40% vertebral height loss, severe grade with ≥40%–2/3 vertebral height loss, and collapsed grade with ≥2/3 vertebral height loss. The CVF detection base model was mainly composed of convolution layers that include convolution kernels of different sizes, pooling layers, up-sampling layers, feature merging layers, and residual modules. When the model loss function could not be further decreased with additional training, the model was considered to be optimal and termed ‘base-model 1.0’. A user-friendly interface was also developed, with the synthesized software termed ‘Ofeye 1.0’.

Results

Counting cases and with minimal and mild OVFs included, base-model 1.0 demonstrated a specificity of 97.1%, a sensitivity of 86%, and an accuracy of 93.9% for the 704 testing cases. In total, 33 OVFs in 30 cases had a false negative reading, which constituted a false negative rate of 14.0% (30/215) by counting all OVF cases. Eighteen OVFs in 15 cases had OVFs of ≥ moderate grades missed, which constituted a false negative rate of 7.0% (15/215, i.e., sensitivity 93%) if only counting cases with ≥ moderate grade OVFs missed. False positive reading was recorded in 13 vertebrae in 13 cases (one vertebra in each case), which constituted a false positivity rate of 2.7% (13/489). These vertebrae with false positivity labeling could be readily differentiated from a true OVF by a human reader. The software Ofeye 1.0 allows ‘batch processing’, for example, 100 radiographs can be processed in a single operation. This software can be integrated into hospital PACS, or installed in a standalone personal computer.

Conclusions

A user-friendly software program was developed for CVF detection on elderly women’s lateral chest radiographs. It has an overall low false positivity rate, and for moderate and severe CVFs an acceptably low false negativity rate. The integration of this software into radiological practice is expected to improve osteoporosis management for elderly women.

Annotations of Lung Abnormalities in the Shenzhen Chest X-ray Dataset for Computer-Aided Screening of Pulmonary Diseases

Developments in deep learning techniques have led to significant advances in automated abnormality detection in radiological images and paved the way for their potential use in computer-aided diagnosis (CAD) systems. However, the development of CAD systems for pulmonary tuberculosis (TB) diagnosis is hampered by the lack of training data that is of good visual and diagnostic quality, of sufficient size, variety, and, where relevant, containing fine region annotations. This study presents a collection of annotations/segmentations of pulmonary radiological manifestations that are consistent with TB in the publicly available and widely used Shenzhen chest X-ray (CXR) dataset made available by the U.S. National Library of Medicine and obtained via a research collaboration with No. 3. People’s Hospital Shenzhen, China. The goal of releasing these annotations is to advance the state-of-the-art for image segmentation methods toward improving the performance of fine-grained segmentation of TB-consistent findings in digital Chest X-ray images. The annotation collection comprises the following: 1) annotation files in JSON (JavaScript Object Notation) format that indicate locations and shapes of 19 lung pattern abnormalities for 336 TB patients; 2) mask files saved in PNG format for each abnormality per TB patient; 3) a CSV (comma-separated values) file that summarizes lung abnormality types and numbers per TB patient. To the best of our knowledge, this is the first collection of pixel-level annotations of TB-consistent findings in CXRs.

Dataset:https://data.lhncbc.nlm.nih.gov/public/Tuberculosis-Chest-X-ray-Datasets/Shenzhen-Hospital-CXR-Set/Annotations/index.html.

The value of magnetic resonance imaging and computed tomography in the study of spinal disorders

Computed tomography (CT) and magnetic resonance imaging (MRI) have replaced conventional radiography in the study of many spinal conditions, it is essential to know when these techniques are indicated instead of or as complementary tests to radiography, which findings can be expected in different clinical settings, and their significance in the diagnosis of different spinal conditions. Proper use of CT and MRI in spinal disorders may facilitate diagnosis and management of spinal conditions. An adequate clinical approach, a good understanding of the pathological manifestations demonstrated by these imaging techniques and a comprehensive report based on a universally accepted nomenclature represent the indispensable tools to improve the diagnostic approach and the decision-making process in patients with spinal pain. Several guidelines are available to assist clinicians in ordering appropriate imaging techniques to achieve an accurate diagnosis and to ensure appropriate medical care that meets the efficacy and safety needs of patients. This article reviews the clinical indications of CT and MRI in different pathologic conditions affecting the spine, including congenital, traumatic, degenerative, inflammatory, infectious and tumor disorders, as well as their main imaging features. It is intended to be a pictorial guide to clinicians involved in the diagnosis and treatment of spinal disorders.

CT detects more osteoporotic endplate depressions than radiograph: a descriptive comparison of 76 vertebrae

This study analyzed elderly women who had chest radiograph and chest CT with indications other than spine disorders. Using CT images as reference, the study demonstrates that radiograph can miss a high portion of mild endplate depression. Detection of endplate depression is confounded by the limitation of projectional overlay for radiograph.

INTRODUCTION

The definition of radiographic OVF (osteoporotic vertebral fracture) remains controversial. Some authors suggest all OVFs should demonstrate endplate fracture/depression on radiograph. Using CT image as the reference, our study tests the hypothesis that a considerable portion of endplate depressions not seen on radiograph can be detected on CT.

METHODS

We retrospectively analyzed 46 female cases (age: 67-94 years) who had both chest radiography and chest CT with indications other than spine disorders. Sixty-six "vertebrae of interest" were identified on radiograph; then, CT images were read side-by-side with lateral chest radiograph.

RESULTS

Thirty-eight vertebrae (38/66) had anterior wedging deformity with height loss of < 20% while without radiographic endplate depression. Among them, 28 vertebrae had endplate depression and 8 vertebrae had no endplate depression on CT, while 2 vertebrae with "very" minimal deformity were read as normal on CT. In 9 vertebrae (9/66) with anterior wedging and height loss of ≥ 20%, all had additional endplate depression seen on CT. Five vertebrae (5/66) had ambiguous endplate depression on radiograph, 3 had endplate depression on CT while the other 2 vertebrae in one patient were false positive due to X-ray projection. There were 14 short height vertebrae (14/66) where middle and anterior heights were reduced to the same extent while did not show apparent anterior wedging or bi-concaving. Four cases each had one short height vertebra, and all had endplate depression on CT. Another 4 cases had 2, 2, 3, and 3 adjacent short height vertebrae, respectively, and all did not show endplate depression on CT. In addition, inspection of spine CT showed 10 vertebrae in 9 cases appeared normal on radiograph while demonstrated endplate depression on CT.

CONCLUSION

With CT images as reference, radiograph can miss a high portion of mild endplate depressions.

Differences in pulmonary nodular consolidation and pulmonary cavity among drug-sensitive, rifampicin-resistant and multi-drug resistant tuberculosis patients: a computerized tomography study with history length matched cases

Background

There have been concerns that literature described radiological feature differences between drug-sensitive pulmonary tuberculosis (DS-PTB) and multidrug-resistant (MDR)-PTB were confounded by that MDR-PTB cases tend to have a longer history. Using history length matched DS-PTB and MDR-PTB cases from a well-defined urban region in Dalian, we retrospectively analysed the CT feature differences of these paired cases with a focus on pulmonary nodular (PN) consolidation and pulmonary cavity (PC).

Methods

There were 33 consecutive MDR-PTB cases [inclusive of rifampicin-resistant (RR) cases, 27 males and 6 females, mean age: 49.2 years], with 19 cases had a history of <1 month and 8 and 6 cases had a history of 1–6 and >6 months respectively. To pair the MDR-PTB cases with history length, matched 33 cases of DS-PTB patients (21 males and 12 females, mean age: 56.5 years) were included. All patients were new PTB without HIV infection. The first CT exams prior to treatment were analysed.

Results

Compared with DS cases, MDR cases had a much higher prevalence of PN (75.76% vs. 45.45%) and a higher number of PN per positive case for PN (6.2 vs.1.53). For the cases >1 month history, MDR-PTB had a higher number of PC per positive case than that of DS-PTB cases (7.18 vs. 2.36). To differentiate DS-PTB from MDR-PTB, receiver operating characteristic (ROC) analysis showed a cutoff PN number of ≥3 had 48.5% sensitivity and 93.9% specificity, and a cutoff PC number of ≥4 had 39.4% sensitivity and 84.9% specificity. The lung field distribution of all lesions tended to be wider for MDR-PTB cases. MDR-PTB cases appeared to be associated with a faster progression in the absence of treatment.

Conclusions

MDR-TB is likely intrinsically more invasive than DS-TB. Multiple PN and Multiple PC are promising signs for the suspicion of MDR-PTB on chest imaging.

Bi-exponential fitting excluding b=0 data improves the scan-rescan stability of liver IVIM parameter measures and particularly so for the perfusion fraction

BACKGROUND

A prerequisite to translating intravoxel incoherent motion (IVIM) imaging into meaningful clinical applications is sufficient scan-rescan reproducibility. This study aims to confirm the hypothesis that IVIM data fitting by not using b=0 images will improve the stability of liver IVIM measurement.

METHODS

Healthy volunteers' liver IVIM images were prospectively acquired using a 1.5-T magnet or a 3.0 T with 16 b-values. Repeatability study subjects were scanned twice during the same session, resulted in 35 paired scans for 35 subjects (11 men, mean age: 41.82 years, range: 32-60 years; 24 women, mean age: 42.67 years, range: 20-71 years). IVIM analysis was performed with full-fitting and segmented-fitting with a threshold b-value of 60 s/mm2, and fitting started from b=0 s/mm2 or from b=2 s/mm2. Reproducibility study subjects were scanned and then rescanned with an interval of 5-18 days, resulted in 20 paired scans for 11 subjects (4 men, mean age: 26.25 years, range: 25-27 years; 7 women, mean age: 25.57 years, range: 24-27 years). IVIM analysis was performed with segmented-fitting with a threshold b-value of 50 s/mm2, and fitting started from b=0 s/mm2 or from b=3 s/mm2.

RESULTS

Fitting without b=0 data generally improved the repeatability and reproducibility for both PF and Dslow, and particularly so for PF. For with b=0 data segmented fitting repeatability, PF had within-subject standard deviation of 0.019, bland-Atman 75% agreement limit of -31.52% to 28.35%, and ICC of 0.647, while these values were 0.009, -20.78% to 16.86%, and 0.837 for without b=0 analysis. Though the repeatability and reproducibility for Dfast generally also improved, they remained suboptimal. Measurement stability was better for repeatability than for reproducibility.

CONCLUSIONS

Scan-rescan repeatability and reproducibility of liver IVIM parameters can be improved by fitting without b=0 data, which is particularly so for PF.

'Healthier Chinese spine': an update of osteoporotic fractures in men (MrOS) and in women (MsOS) Hong Kong spine radiograph studies

For the MrOS (Hong Kong) and MsOS (Hong Kong) baseline (BL) studies, community-dwelling 2,000 Chinese men (mean age: 72.3 years) and 2,000 Chinese women (mean age: 72.5 years) were recruited from 2001 to 2003. These two studies have spanned two decades till now. This review summarizes our spine radiograph results. Senile and post-menopausal osteoporosis were associated with intervertebral disc volume reduction; and in women, menopause accelerates disc degeneration. Elderly women's osteoporotic vertebral fracture (OVF) prevalence was double of that of elderly men. For year-4 follow-up (FU), male participants with BL OVF had little increased risk for further OVF. In our study comparing OVF rates in age-matched Hong Kong Chinese women and Italian Caucasian women (mean age: 74.1 years), endplate and/or cortex fracture (ECF) prevalence was 26% for Chinese and 47% for Italian. OVF with ≥40% vertebral height loss was recorded among 9.5% of the Chinese subjects while among 26% of the Italian subjects. OVFs in Italian subjects were more likely to be multiple and generally severer. Clinical spine fractures were recorded 133 cases/100,000 person-years in MrOS (Hong Kong) participants and 273 cases/100,000 person-years in MsOS (Hong Kong) participants. Literature review suggests the clinical vertebral fracture rates among elderly Hong Kong Chinese subjects are approximately half of those of American, Australian, and Canadian subjects. Data synthesis suggests elderly Caucasians have a higher degenerative spondylolisthesis prevalence, being approximately 70% higher than that of elderly Hong Kong Chinese. Literature review of other authors' publications shows, compared with Caucasians, Chinese have a much lower incident rate of back pain. We conclude that elderly Chinese have a generally healthier spine relative to elderly Caucasians.

Gender-specific liver aging and magnetic resonance imaging

The number of imaging studies performed on elderly individuals will increase in the next several decades. It is important to understand normal age-related changes in the structural and functional imaging appearance of the liver. This article highlights a number of liver aging aspects which are particularly relevant to magnetic resonance imaging (MRI). Physiology of aging liver is associated with a reduction in size, in perfusion, and in function. Pulsed echo-Doppler showed substantial reduction of portal flow in elderly subjects, particularly those after the age of 75 years old. An MRI biomarker diffusion derived vessel density (DDVD) demonstrated that liver microperfusion volume in healthy females starts to decrease even before menopause age. Liver fat content and iron content increase with aging, and the change is more substantial in women after menopause. Adult men have higher liver fat and iron contents than women from the start and change less during aging. Nonalcoholic fatty liver disease (NAFLD) is very common among assumed healthy subjects. There is a male predominance of NAFLD from the paediatric population up to fifth decade of life in adults. After the age of 60 years, women overtake their male counterparts in prevalence of NAFLD. Higher liver fat leads to decreased apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM)-D_slow measures. Higher liver iron content shortens T2* measure, lower ADC and IVIM-D_slow measures, increases imaging noises and decreases liver visibility. Young women have high liver T1rho value and then decrease substantially, while liver T1rho in men remains relatively unchanged with aging. In positron emission tomography (PET) studies, aging is associated with an increase of both liver fluorine-18-fluorodeoxyglucose maximum standard uptake and mean standard uptake values.

Illustration of a number of atypical computed tomography manifestations of active pulmonary tuberculosis

Tuberculosis is a serious public health challenge facing mankind and one of the top ten causes of death. Diagnostic imaging plays an important role, particularly for the diagnosis and treatment planning of tuberculosis patients with negative microbiology results. This article illustrates a number of atypical computed tomography (CT) appearances of pulmonary tuberculosis (PTB), including (I) clustered micronodules (CMNs) sign; (II) reversed halo sign (RHS); (III) tuberculous pneumatocele; (IV) hematogenously disseminated PTB with predominantly diffuse ground glass opacity manifestation; (V) hematogenously disseminated PTB with randomly distributed non-miliary nodules; (VI) PTB changes occur on the background of emphysema or honeycomb changes of interstitial pneumonia; and (VII) PTB manifesting as organizing pneumonia. While the overall incidence of PTB is decreasing globally, the incidence of atypical manifestations of tuberculosis is increasing. A good understanding of the atypical CT imaging changes of active PTB shall help the diagnosis and differential diagnosis of PTB in clinical practice.