Movienet: Deep space-time-coil reconstruction network without k-space data consistency for fast motion-resolved 4D MRI

PURPOSE

To develop a novel deep learning approach for 4D-MRI reconstruction, named Movienet, which exploits space-time-coil correlations and motion preservation instead of k-space data consistency, to accelerate the acquisition of golden-angle radial data and enable subsecond reconstruction times in dynamic MRI.

METHODS

Movienet uses a U-net architecture with modified residual learning blocks that operate entirely in the image domain to remove aliasing artifacts and reconstruct an unaliased motion-resolved 4D image. Motion preservation is enforced by sorting the input image and reference for training in a linear motion order from expiration to inspiration. The input image was collected with a lower scan time than the reference XD-GRASP image used for training. Movienet is demonstrated for motion-resolved 4D MRI and motion-resistant 3D MRI of abdominal tumors on a therapeutic 1.5T MR-Linac (1.5-fold acquisition acceleration) and diagnostic 3T MRI scanners (2-fold and 2.25-fold acquisition acceleration for 4D and 3D, respectively). Image quality was evaluated quantitatively and qualitatively by expert clinical readers.

RESULTS

The reconstruction time of Movienet was 0.69 s (4 motion states) and 0.75 s (10 motion states), which is substantially lower than iterative XD-GRASP and unrolled reconstruction networks. Movienet enables faster acquisition than XD-GRASP with similar overall image quality and improved suppression of streaking artifacts.

CONCLUSION

Movienet accelerates data acquisition with respect to compressed sensing and reconstructs 4D images in less than 1 s, which would enable an efficient implementation of 4D MRI in a clinical setting for fast motion-resistant 3D anatomical imaging or motion-resolved 4D imaging.

Clinical outcomes following COVID-19 infection in ethnic minority groups in the UK: a systematic review and meta-analysis

OBJECTIVES

This study evaluated the differences in clinical outcomes of COVID-19 infection between ethnic minorities and the White ethnic group in the UK.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

This study included adult residents in the UK with confirmed COVID-19 infection. The outcomes evaluated in this study were mortality, intensive care unit (ICU) admission and invasive mechanical ventilation (IMV). Outcome data were compared between individuals from ethnic minority groups and individuals from a White ethnic background. MEDLINE, Embase, Cochrane, medRxiv and PROSPERO were searched for articles published between May 2020 and April 2021. The risk of bias was evaluated using the Newcastle-Ottawa Scale checklist.

PROSPERO ID

CRD42021248117.

RESULTS

Fourteen studies (767,177 participants) were included in the current review. In the adjusted analysis, the pooled odds ratio (OR) for mortality following COVID-19 infection was higher for Black (OR 1.83, 95% confidence interval [CI]: 1.21-2.76, number of studies [k] = 6), Asian (OR 1.16, 95% CI: 0.85-1.57, k = 6) and Mixed and Other (MO) ethnic groups (OR 1.12, 95% CI: 1.04-1.20, k = 5) compared with the White ethnic group. The adjusted and unadjusted ORs of ICU admission for many of the ethnic minority groups were more than double the OR values for the White ethnic group (Black ethnic group = OR 2.32, 95% CI: 1.73-3.11, k = 5; Asian ethnic group = OR 2.34, 95% CI: 1.89-2.90, k = 5; and MO ethnic group = OR 2.26, 95% CI: 1.64-3.11, k = 4). In the adjusted analysis for IMV, the ORs were similarly significantly raised in ethnic minority groups compared with the White ethnic group (Black ethic group = OR 2.03, 95% CI: 1.80-2.29, k = 3; Asian ethnic group = OR 1.84, 95% CI: 1.20-2.80, k = 3; and MO ethnic group = OR 2.09, 95% CI: 1.35-3.22, k = 3).

CONCLUSION

This review found that in the UK, Black, Asian and MO ethnic groups experienced increased COVID-19-related disease severity and mortality compared with the White ethnic group majority.

Comparison of Success of Clomiphene citrate and Letrozole in Ovulation Induction

The study was carried out to evaluate which drug is better in ovulation induction between clomiphene citrate and letrozole. The study was carried out in the infertility unit of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka and Centre for Assisted Reproduction (CARE) at Bangladesh Institute of Research and Rehabilitation in Diabetes Endocrine and Metabolic Disorders (BIRDEM), Dhaka from January 2007 to December 2007. One hundred and sixty five cases were taken for the study. It was a prospective interventional comparative study of clomiphene citrate and letrozole in infertile cases. The patients were divided into three groups. Group I--newly detected cases of sub fertility studied with clomiphene citrate. Group II--clomiphene citrate resistant cases studied with letrozole, Group III--newly detected cases of sub fertility studied with letrozole. The cases were followed up for outcome; (ovulation). The TVS was done on 12th or 13th day of menstruation and level of serum progesterone on 21st day of menstrual cycle to see the evidence of ovulation. Endometrial thickness was also measured. The data was collected on a predesigned questionnaire. The variables that influenced the study were-age, occupation, socioeconomic status, menstrual cycle, marital age, parity, history of MR, history of abortion, past medical and surgical history. In the current study it was observed that the signs of ovulation were significantly (p<0.05) higher in Group I treated with clomiphene citrate in comparison to Group II clomiphene citrate resistant cases treated with letrozole. The rate of ovulation was higher in Group I than that of Group III treated with letrozole, but the difference was not statistically significant (p>0.05). The signs of ovulation were present in 45(81.8%) cases in Group I, 33(60.0%) cases in Group II and 37(67.3%) cases in Group III. This findings of the study suggested that clomiphene citrate is higher successful than letrozole though not statistically significant. Letrozole can be preferred in clomiphene citrate resistant cases before starting other expensive therapies.

A systematic review of the management and outcomes of pregnancy in Glanzmann thrombasthenia

Glanzmann Thrombasthenia (GT) is a rare autosomal recessive disorder which usually manifests as severe mucocutaneous bleeding and is caused by deficiency of the platelet glycoprotein IIb-IIIa. Pregnancy in women with GT presents particular challenges as there is increased risk of both maternal and foetal bleeding. To improve understanding and clarify the optimum management of pregnancy in this disorder, we performed a systematic review of the world literature of pregnancy and GT. This identified three single-centre case series of patients with GT that included brief descriptions of women in pregnancy and 31 detailed case reports of 40 pregnancies in 35 women that resulted in 38 live births. Among the detailed case reports, ante-natal bleeding was described in 50% of pregnancies but was usually mild and occurred at mucocutaneous sites. Primary postpartum haemorrhage (PPH) was reported in 34% of pregnancies and secondary PPH in 24%. PPH was frequently severe and occurred up to 20 days after delivery. There was a wide variation in approach to prevention and treatment of PPH but most women received platelet transfusion, sometimes with additional recombinant FVIIa and anti-fibrinolytics. Maternal alloimmunization against platelet antigens was reported in 73% of pregnancies and was associated with four neonatal deaths. These data emphasize the need for multidisciplinary management of pregnancy in women with GT. Delivery plans should recognize the need for prevention and aggressive treatment of PPH and should minimize foetal bleeding risk in pregnancies complicated by alloimmunization.

Papillary thyroid carcinoma presenting as an asymptomatic pelvic bone metastases

Thyroid carcinoma is rare comprising 1% of all malignancies and commonly presents as a neck lump. Papillary thyroid carcinoma unlike follicular thyroid carcinoma tends not to metastasise to distant sites. We present a case of papillary thyroid carcinoma presenting as a solitary asymptomatic pelvic bone metastases and highlight current management of bone metastases. A 59-year old female was found on abdominal computerised tomography to have an incidental finding of a 4.5 cm soft tissue mass in the right iliac bone. Biopsy of the lesion confirmed metastatic thyroid carcinoma. There was no history of a neck lump, head and neck examination was normal. Further imaging confirmed focal activity in the right lobe of the thyroid. A total thyroidectomy and level VI neck dissection was performed and histology confirmed follicular variant of papillary carcinoma. Early detection of bone metastases have been shown to improve prognosis and thyroid carcinoma should be considered as a potential primary malignancy.

Outcome of case finding among relatives of patients with known heterozygous familial hypercholesterolaemia

OBJECTIVES

To assess the feasibility of detecting new cases of heterozygous familial hypercholesterolaemia by using a nurse led genetic register.

DESIGN

Case finding among relatives of patients with familial hypercholesterolaemia.

SETTING

Two lipid clinics in central and south Manchester.

SUBJECTS

259 (137 men and 122 women) probands and 285 first degree relatives.

RESULTS

Of the 200 first degree relatives tested, 121 (60%) had inherited familial hypercholesterolaemia. The newly diagnosed patients were younger than the probands and were generally detected before they had clinically overt atherosclerosis. Concentrations of serum cholesterol were, respectively, 8.4 (1.7 SD) mmol/l and 8.1 (1.9 SD) mmol/l in affected men and women and 5.6 (1.0 SD) mmol/l and 5.6 (1.1 SD) mmol/l in unaffected men and women. Screening for risk factors as recommended in recent guidelines for coronary heart disease prevention would have failed to identify most of the affected relatives in whom hypertension, diabetes mellitus, cigarette smoking, and obesity were uncommon.

CONCLUSIONS

By performing cholesterol tests on 200 relatives, 121 new patients with familial hypercholesterolaemia were discovered. Because 1 in 500 people in the United Kingdom are affected by this condition, to detect a similar number by population screening over 60 000 tests would be required, and only a few of these patients would have been detected had cholesterol testing been restricted to those with other risk factors for coronary heart disease. A case exists for organising a genetic register approach, linking lipid clinics nationally.

Endocarditis in an urban hospital in the 1990s

OBJECTIVES

To analyze the clinical characteristics and outcome of 159 consecutive patients with endocarditis who presented to an inner-city hospital from 1990 onward and to elucidate the most current problems and advances in the management of endocarditis.

METHODS

One hundred eighty-two consecutive cases (in 159 patients) met diagnostic criteria for endocarditis, including histopathologic evidence or multiple positive blood cultures without another primary source, and appropriate signs or symptoms. Transthoracic echocardiography was performed for 171 cases, and 36 patients underwent transesophageal echocardiography.

RESULTS

Sixty-seven percent of the patients were known drug users; more than 80% of these were positive for human immunodeficiency virus. Fever, malaise, and fatigue occurred in more than 95%, but other signs were neither sensitive nor specific, and classic microvascular phenomena were uncommon. Blood cultures were positive in 96%, all 7 patients with negative cultures had received prior antibiotic therapy. Staphylococcus aureus was the most common organism, and a significant increase in S aureus infections was noted for tricuspid endocarditis (chi 2 = 71.07, P = .003). The mitral (n = 51) and tricuspid (n = 49) valves were the most common sites of infection. Underlying heart disease was only identified in one fourth of the cases. Transesophageal echocardiography identified vegetation in 34 of 36 studies, 16 of which had negative transthoracic echoes. Five of 6 patients with documented abscesses died within 7 months. A systemic embolism occurred in nearly a third (n = 51) of the cases. Large vegetations (> 20 mm) were significantly correlated with an increased frequency of embolization (chi 2 = 6.77, P = .009), but vegetation mobility was not. Cardiac surgery was performed in 24 patients; there were 2 perioperative deaths.

CONCLUSIONS

The changing clinical spectrum of endocarditis exemplified in our series has important implications for diagnosis and management. Close attention to appropriate risk factors can contribute to optimal management of those factors and improve prognosis.