Determination of radiation dose and low-dose protocol for digital chest tomosynthesis using radiophotoluminescent (RPL) glass dosimeters.

PURPOSE: This study aimed to determine a low-dose protocol for digital chest tomosynthesis (DTS). METHODS: Five simulated nodules with a CT number of approximately 100 HU with size diameter of 3, 5, 8, 10, and 12 mm were inserted into an anthropomorphic chest phantom (N1 Lungman model), and then scanned by DTS system (Definium 8000) with varying tube voltage, copper filter thickness, and dose ratio. Three radiophotoluminescent (RPL) glass dosimeters, type GD-352 M with a dimension of 1.5 × 12 mm, were used to measure the entrance surface air kerma (ESAK) in each protocol. The effective dose (ED) was calculated using the recorded total dose-area-product (DAP). The signal-to-noise ratio (SNR) was determined for qualitative image quality evaluation. The image criteria and nodule detection capability were scored by two experienced radiologists. The selected low-dose protocol was further applied in a clinical study with 30 pulmonary nodule follow-up patients. RESULTS: The average ESAK obtained from the standard default protocol was 1.68 ± 0.15 mGy, while an ESAK of 0.47 ± 0.02 mGy was found for a low-dose protocol. The EDs for the default and low-dose protocols were 313.98 ± 0.72 µSv and 100.55 ± 0.28 µSv, respectively. There were small non-significant differences in the image criteria and nodule detection scoring between the low-dose and default protocols interpreted by two radiologists. The effective dose of 98.87 ± 0.08 µSv was obtained in clinical study after applying the low-dose protocol. CONCLUSIONS: The low-dose protocol obtained in this study can substantially reduce radiation dose while preserving an acceptable image quality compared to the standard protocol.

Screening values of carcinoembryonic antigen and cytokeratin 19 fragment for lung cancer in combination with low-dose computed tomography in high-risk populations: Initial and 2-year screening outcomes.

OBJECTIVES: To assess added screening value of Carcinoembryonic Antigen (CEA) and Cytokeratin 19 Fragment (CYFRA 21-1) in combination with LDCT beyond LDCT alone and likelihood ratio of positive (LHR+) of their combination for lung cancer in high-risk populations with indeterminate and positive LDCT after initial screening and 2-year follow up. MATERIALS AND METHODS: LDCT was performed annually at baseline and for 2 years in 634 heavy smokers (>30 pack-years) who were aged 50-70 years, and it was classified as negative, indeterminate, or positive (suspicious for lung cancer). Serum CEA and CYFRA 21-1 were examined and followed with LDCT in the indeterminate and positive LDCT groups and defined as positive with an abnormal level of either CEA or CYFRA 21-1. RESULTS: A total of 17 lung cancer cases were diagnosed (9 from initial screening and 8 from follow-up cycles). Seventy and 22 patients had indeterminate and positive baseline LDCT, respectively. Among indeterminate baseline LDCT, the LHR+ for lung cancer diagnosed after initial screening with a positive marker was 6.61 (p = .039) and 1.51 (p = .502) with a negative marker. After 2 years follow up, the LHR+ was 6.31 (p = .004) and 0.86 (p = .677), respectively. Among positive baseline LDCT, the LHR+ for lung cancer diagnosed after initial round with positive and negative markers was 69.44 (p < 0.001) and 11.57 (p = .015), respectively. The corresponding LHR+ after 2-year round was 13.61 (p = .002) and 18.15 (p = .001), respectively. The combinations of CEA/CYFRA 21-1 and LDCT, and CEA and LDCT had crude and adjusted added value beyond LDCT alone (crude: 8%, p = .033 and 7%, p = .038; adjusted: 4%, p = .019 and 4%, p = .029, respectively). CONCLUSIONS: CEA in combination with LDCT significantly increases the value of lung cancer screening compared with using LDCT alone particularly in participants with indeterminate baseline LDCT in both initial and 2-year screening outcomes.

Ultrasound surveillance for cholangiocarcinoma in an endemic area: A prove of survival benefits.

BACKGROUND AND AIM: Cholangiocarcinoma (CCA) is an aggressive malignancy with rapid progression and poor prognosis. Abdominal ultrasound surveillance may detect early-stage malignancy and improve surgical outcome. However, little data exist on the benefits of abdominal ultrasound surveillance in populations at high risk for CCA development in an endemic area. This study compared survival outcomes of CCA patients recruited through abdominal ultrasound surveillance program and those presented to the hospital independent of surveillance. METHODS: The surveillance population-based cohort was 4225 villagers in Northern Thailand, aged 30-60 years, who consented to a 5-year abdominal ultrasound surveillance program, which included interval ultrasound examinations every 6 months. The non-surveillance cohort was hospital-based CCA patients diagnosed during April 2007 to November 2015. Numbers of operable tumors, percentages of R0 resection, and survival analyses were compared between the two cohorts. RESULTS: There were 48 and 192 CCA patients in the surveillance and the non-surveillance cohorts, respectively. Of these, 37/48 (77.1%) and 22/192 (11.5%) were in an operable stage and R0 resections performed in 36/48 (97.3%) and 14/192 (63.6%), respectively. The median survival in each group was 31.8 and 6.7 months, respectively (with correction of lead time bias) (P < 0.0001). By multivariate analysis, abdominal ultrasound surveillance (hazard ratio [HR] = 0.41; P = 0.012), operable stage (HR = 0.11; P < 0.001), and serum albumin ≥ 3.5 g/dL (HR = 0.42; P < 0.001) were significantly associated with decreased mortality, whereas size of CCA (HR = 1.11; P < 0.001), serum alanine aminotransferase > 40 IU/L (HR = 1.71; P = 0.017), and tumor recurrence (HR = 4.86; P = 0.017) were associated with increased mortality. CONCLUSION: Abdominal ultrasound surveillance provided survival benefits and should be considered in areas highly endemic for CCA to reduce mortality.

Longterm follow-up of small pancreatic cystic lesions in liver transplant recipients.

Incidental small pancreatic cystic lesions (PCLs) are often found on preoperative imaging in patients undergoing orthotopic liver transplantation (OLT). Although these are considered benign or of low malignant potential, the influence of immunosuppression after OLT may be of concern. The aim of this study was to observe the longterm outcome of these small PCLs in post-OLT patients. An institutional OLT database of 1778 consecutive OLT patients from January 2000 to December 2010 was analyzed. Computed tomography, magnetic resonance imaging, or endoscopic ultrasound at the time of OLT and all subsequent imaging, cytology, fluid analysis of PCLs, and patient status were evaluated. A total of 70 patients with 182 PCLs, of benign or low malignant potential, were identified with a mean follow-up time of 64 months. At initial diagnosis of PCLs in 48 patients, 7 branch duct-type intraductal papillary mucinous neoplasms (B-IPMNs), 1 serous cystadenoma (SCA), and 40 nonspecific benign cysts were identified. Final diagnosis at the end of the follow-up revealed 16 B-IPMNs, 3 SCAs, and a mixed acinar-neuroendocrine carcinoma, in which the latter developed 9 years after initial diagnosis of B-IPMN. During the follow-up time, average increase in size and number of PCLs were 4.5 mm and 1.4, respectively (P < 0.001 for both). The majority of incidental PCLs in OLT patients showed an indolent behavior despite immunosuppression. Risk of malignancy development was very low and comparable with normal population. Liver Transplantation 23 324-329 2017 AASLD.

Ultrasound screening for cholangiocarcinoma could detect premalignant lesions and early-stage diseases with survival benefits: a population-based prospective study of 4,225 subjects in an endemic area.

BACKGROUND: Thailand has a high incidence of cholangiocarcinoma (CCA), particularly in the north and northeastern regions. Most CCA patients come at a late, unresectable stage and presently no optimal screening test for CCA has been established. We determined the prevalence of CCA in a remote northern village and explored if screening could lead to early detection and survival benefits. METHODS: A 5-year population-based study was started in October, 2011 for consented Thai individuals, aged 30-60 years. The screening program comprised blood testing, stool examination and serial ultrasonography every 6 months. RESULTS: During the first 3 years, 4,225 eligible individuals were enrolled. CCA was detected in 32 patients, with a mean age of 51.9 years (41-62 years), and 21/32 cases were at a curative resectable stage. The prevalence rate of CCA was 165.7 per 100,000 and one- and two-year incidence rate was 236.7/100,000 and 520.7/100,000, respectively. One- and 2-year overall survival rates of CCA patients were 90.9 and 61.5 %, respectively. Prognosis was better in resectable cases with 100 % 1-year and 77.8 % 2-year survival rates. Interestingly, premalignant pathological lesions (stage 0) were identified in 11 cases with 100 % 3-year survival rate. Serum biomarkers and alkaline phosphatase were not sufficient to detect early-stage disease. In 22 patients, stool samples were positive for Opistorchis viverrini, based on polymerase chain reaction. CONCLUSION: Detection of premalignant lesions and early-stage resectable CCA by ultrasonography resulted in improved clinical outcome. Ultrasonography should be offered as a first screening tool for CCA in an endemic area until other useful biological markers become available.

Does hepatobiliary phase sequence qualitatively outperform unenhanced T1-weighted imaging in assessment of the ablation margin 24 hours after thermal ablation of hepatocellular carcinomas?

PURPOSE: To retrospectively determine whether hepatobiliary phase (HBP) sequence outperforms unenhanced T1-weighted imaging (uT1wI) in distinguishing the ablation margin (AM) from hepatocellular carcinoma (HCC) 24 h after thermoablation. MATERIAL AND METHODS: Ninety-one patients [mean age, 65.7 years; 68 M/23F] with 138 HCCs (>6 months follow-up) underwent pre- and postablation gadoxetate disodium-enhanced MRI. AM showed a hyperintense middle zone (MZ) surrounding central hypo- or hyperintense HCCs on uT1wI, and an intermediate-intense MZ encompassing central hypo- or hyperintense HCCs during HBP. The visible AM was defined as persistent MZ around HCCs, which were demarcated from MZ, or peripherally band encompassing MZ, which were not demarcated from HCC. The indefinite AM was defined as no demarcating HCCs from MZ. The ability to distinguish AM from HCC was classified as visible or indefinite on axial (ax)-uT1wI, ax-HBP, coronal (cor)-HBP, and combined all images. To investigate the AM visibility during HBP, significance of differences upon comparison of ax-uT1wI with combined images was analyzed. Preablation liver-tumor contrast ratio (LTCR) on ax-uT1wI and ax-HBP sequence is compared between the visible and indefinite AM. RESULTS: The McNemar test demonstrated a significant increase (p < 0.05) in visible AM from ax-uT1wI (60), to ax-HBP (70), cor-HBP (79), and combined images (83). TLCR with visible AM was significantly higher than that with indefinite AM on ax-uT1wI (0.4 vs. 0.2, p = 0.001) and ax-HBP sequence (0.9 vs. 0.6, p = 0.004). CONCLUSIONS: HBP sequence might have higher feasibility to distinguish AM from tumor than ax-uT1wI. The TLCR value in visible AM was higher than that in indefinite AM on both ax-uT1wI and ax-HBP sequences.