Construction of the Tuen Mun–Chek Lap Kok Link Sub-sea Tunnels in Hong Kong

The entire Tuen Mun–Chek Lap Kok Link (TM-CLKL) was commissioned on 27 December 2020 and comprises a 9 km dual twolane carriageway between Tuen Mun and North Lantau, Hong Kong. The challenges for the construction of the TM-CLKL tunnels included sub-sea tunnelling up to 55 m below sea level in mixed ground geology that required replacement of tunnel boring machine (TBM) cutting tools at hyperbaric pressure up to 5.8 bars; replacement of worn TBM cutting tools in complicated ground conditions; construction of approach tunnels in newly reclaimed land subject to long-term consolidation; and construction of cross passages at 100-metre intervals between the two sub-sea tunnels with a risk of sea water ingress at 5.5 bars. This project has deployed sophisticated techniques to surmount the challenges encountered during construction of the five-kilometre-long sub-sea tunnels. These included the use of the world’s largest slurry-type Mixshield TBM, 17.63 m in diameter, for the construction of the northern approach tunnel, followed by two 14 m diameter slurry-type Mixshield TBMs for the construction of the sub-sea tunnels; use of saturation diving techniques for TBM cutterhead interventions up to 5.8 bars which was the first such works in Hong Kong and one of only a few uses of saturation diving in tunnelling worldwide; use of ground freezing techniques in complicated ground conditions for TBM interventions to change worn cutting tools at the TBM cutterhead; TBM tunnelling in newly reclaimed land at the northern landfall and the southern landfall; and the construction of cross passages by mini-TBM using pipe jacking methods between the two main tunnel tubes which was the first such works ever undertaken anywhere in the world. This paper introduces the successful implementation of these techniques for the satisfactory completion of the TM-CLKL sub-sea tunnels.

Clinical Implications of “Atypia” on Biopsy: Possible Precursor to Lung Cancer?

Background: It is common for biopsies of concerning pulmonary nodules to result in cytologic “atypia” on biopsy, which may represent a benign response or a false negative finding. This investigation evaluated time to diagnosis and factors which may predict an ultimate diagnosis of lung cancer in these patients with atypia cytology on lung nodule biopsy. Methods: This retrospective study included patients of the Stony Brook Lung Cancer Evaluation Center who had a biopsy baseline diagnosis of atypia between 2010 and 2020 and were either diagnosed with cancer or remained disease free by the end of the observation period. Cox Proportional Hazard (CPH) Models were used to assess factor effects on outcomes. Results: Among 106 patients with an initial diagnosis of atypia, 80 (75%) were diagnosed with lung cancer. Of those, over three-quarters were diagnosed within 6 months. The CPH models indicated that PET positivity (SUV ≥ 2.5) (HR = 1.74 (1.03, 2.94)), nodule size > 3.5 cm (HR = 2.83, 95% CI (1.47, 5.45)) and the presence of mixed ground glass opacities (HR = 2.15 (1.05, 4.43)) significantly increased risk of lung cancer. Conclusion: Given the high conversion rate to cancer within 6 months, at least tight monitoring, if not repeat biopsy may be warranted during this time period for patients diagnosed with atypia.

A spectrum of HRCT chest findings in RT-PCR positive asymptomatic COVID-19 patients at a COVID designated hospital in Nepal

Introduction: COVID-19 pandemic is grappling the world with the surge of infection time and again. Clinicians are trying to justify the ethics of public health care. Asymptomatic COVID-19 cases are going undocumented and most of them practice self-isolation. Studies have revealed significant radiological changes among RT-PCR positive asymptomatic COVID-19 cases. Objective: The aim of this cross-sectional study is to characterized chest CT findings of asymptomatic RT-PCR-positive patients in one of the COVID designated hospitals in Nepal. Results: Out of 43, 26 (60.5%) participants had positive Chest CT scan findings consistent with COVID pneumonia. 65% had bilateral and 77% had multifocal lesions. The ground-glass opacities (92%), mixed (ground-glass opacities and consolidation) pattern (30.7%), and consolidation only (34.6%) were common chest CT findings. The median CT score was 3.5 (Interquartile range; 2-6). Conclusion: The majority of the RT-PCR positive asymptomatic patient present with CT scan changes of lungs which are important to determine clinical status, prognosis, and long-term sequel in those cohorts.

Use of saturation diving technique for tunnel boring machine cutterhead intervention in the Tuen Mun–Chek Lap Kok Link Sub-sea Tunnel Project, Hong Kong

The entire Tuen Mun–Chek Lap Kok Link (TM-CLKL) was commissioned on 27 December 2020 and it comprises a 9km-long dual 2-lane carriageway between Tuen Mun and North Lantau, Hong Kong. Construction of the 5km-long sub-sea tunnels was carried out by two 14m diameter Tunnel Boring Machines (TBMs). The tunnel alignment for the TM-CLKL sub-sea tunnel section is in mixed ground condition with the first 500 m in mixed geology of slightly to moderately decomposed granite and completely decomposed granite (CDG), followed by soft ground condition with CDG, alluvial sand, alluvial clay and marine deposit. This mixed ground geology requires regular TBM cutterhead interventions to change the worn-out cutting tools during the tunnelling operation. As the tunnel alignment is up to 55 m below the sea level with the deepest seabed level at -21 mPD, in order to maintain the cutting face stability during the intervention, the intervention pressure could be up to 6 bars. This paper describes different techniques used for TBM interventions under the sea such as trimix bounce mode and saturation mode that appears first time in Hong Kong under a high hyperbaric pressure to change the worn-out cutting tools at the TBM cutterhead.

Overuse of Follow-up Chest Computed Tomography in Patients With Incidentally Identified Nodules Suspicious for Lung Cancer

Purpose: Regardless of professional societies agreed that CT screening inconsistent with recommendation leads to radiation-related cancer and unexpected cost, many patients undergo unnecessary chest CT before treatment. The goal of this study was to assess the overuse of Chest CT in different type of patients.Methods: Data on 1853 patients who underwent pulmonary resection from May 2019 to May 2020 were retrospectively analyzed. Data collected include age, sex, follow-up time, density and size of nodules and frequency of undergoing Chest CT. Pearson χ2 test and logistic regression were conducted to compare the receipt of CT screening.Results: Among 1853 patients in the study, 689 (37.2%) had overused Chest CT during follow-up of the lung cancer. This rate was 16.2% among patients with solid nodules, 57.5% among patients with pure ground glass opacity (pGGO), and 41.4% among patients with mixed ground glass opacity (mGGO) (P<.001). 50.7% in the “age ≤40” group, 39.8% in the “41≤age ≤50” group, 38.7% in the “51≤age ≤60” group, 32.3% in the “61≤age ≤70” group, 27.8% in the “>70” group underwent unnecessary CT (P<.001). Female get more unnecessary CT than male (40.6% vs 32.8%, P<.001). Factors associated with a greater likelihood of Chest CT is the density of nodules (odds ratios [ORs] of 0.53 for mGGO; 0.15 for solid nodule, P<.0001, vs patients with pGGO).Conclusion: roughly 37% patients with pulmonary nodules received Chest CT too frequently despite national recommendations against the practice. Closer adherence to clinical guidelines is likely to result in more cost-effective care.

Correlation between early features and prognosis of symptomatic COVID-19 discharged patients in Hunan, China

To determine the correlation between the clinical, laboratory, and radiological findings and the hospitalization days in Coronavirus Infectious Disease-19 (COVID-19) discharged patients. We retrospectively identified 172 discharged patients with COVID-19 pneumonia from January 10, 2020, to February 28, 2020, in Hunan province. The patients were categorized into group 1 (≤ 19 days) and group 2 (> 19 days) based on the time from symptom onset to discharge. Cough during admission occurred more commonly in group 2 (68.4%) than in group 1 (53.1%, p = 0.042). White blood cell (p = 0.045), neutrophil counts (p = 0.023), Alanine aminotransferase (p = 0.029), Aspartate aminotransferase (p = 0.027) and Lactate dehydrogenase (p = 0.021) that were above normal were more common in group 2. Patients with single lesions were observed more in group 1(17.7%, p = 0.018) and multiple lesions observed more in group 2(86.8%, p = 0.012). The number of lobes involved (p = 0.008) in the CT score (p = 0.001) for each patient was all differences between the two groups with a statistically significant difference. Mixed ground-glass opacity (GGO) and consolidation appearances were observed in most patients. GGO components > consolidation appearance was more common in group 1 (25.0%) than in group 2 (8.0%) with a significant difference (0.015), GGO < consolidation was more common in group 2(71.1%, p = 0.012). From the logistic regression analysis, the CT score (OR, 1.223; 95% CI, 1.004 to 1.491, p = 0.046) and the appearance of GGO > consolidation (OR, 0.150; 95% CI, 0.034 to 0.660, p = 0.012) were independently associated with the hospitalization days. Thus, special attention should be paid to the role of radiological features in monitoring the disease prognosis.

Epidemiological and Clinical Characteristics of Patients with COVID-19 in Arak, Iran

Background: The number of confirmed cases of COVID-19 is increasing. Here we present the clinical characteristics and outcomes of COVID-19 in Arak, Iran. Methods: In this study, 139 COVID-19 confirmed cases from 15 February to 15 March 2020 in Arak, Iran, were investigated. The clinical signs, symptoms, laboratory and radiological findings and outcomes were analyzed. Results: The mean age of the patients was 55.41 years (S.D.: 17.11) and 55.40% of them were males. 26.81% of patients had recently traveled to other epidemic cities. The most common clinical manifestations were fever (71.64%), cough (67.16%), shortness of breath (55.22%), muscle ache (50.00%) and the most prevalent complications were taste and smell disruption (29.5%), weakness (22.3%), anorexia (20.1%) and acute respiratory distress syndrome (ARDS) (15.8%). Almost half of the patients had lymphopenia, an elevated level of erythrocyte sedimentation rate (ESR) and C - reactive protein (CRP). In terms of outcome, 9.3% of patients needed an ICU admission as a result of ARDS in which 15.32% were directly admitted to the ICU. 43.2% of patients have been discharged and the case fatality rate (CFR) was estimated as 11.5%. Conclusion: COVID-19 pneumonia usually occurred at an age older than 50 years and in the male gender. The most common initial clinical laboratories and radiological presentations are fever, cough, lymphopenia with elevated CRP and ESR and Bilateral mixed ground-glass opacities with consolidation.