Chest-abdomen-pelvis Research Articles

Introduction and evaluation of size-specific DLP for radiation dose estimation in CT examinations.

The increased utilization of computed tomography (CT) has raised concerns about patient radiation exposure. Effective dose (ED), which requires precise estimation, is crucial for assessing and managing these risks. Traditional ED estimation methods, which are based on the dose-length product (DLP), often lack accuracy due to variations in patient size and anatomy. This study aims to evaluate the efficacy of size-specific DLP (SS-DLP), a novel metric that combines the size-specific dose estimate (SSDE) with scan length, to provide a more accurate estimation of radiation exposure from CT examinations. Focusing on adult chest-abdomen-pelvis (CAP) scans, we calculated SSDE and SS-DLP and utilized two simulation tools, Radimetrics and WAZA-ARI, for a detailed analysis. Our findings indicate that SS-DLP is highly correlated with EDs from Monte Carlo simulations, suggesting its reliability. Additionally, SS-DLP showed a moderate reduction in errors based on patient sex and body mass index compared to traditional DLP-based methods. Thus, SS-DLP offers a more accurate and personalized radiation exposure estimate, potentially enhancing patient safety.

8248 Glucocorticoid Induced Adrenal Crisis Masked By Metastatic Lung Carcinoma

Abstract Disclosure: N. Abrahimi: None. A. Abrahimi: None. Background: Chronic glucocorticoid use of three weeks or longer can cause hypothalamic-pituitary-adrenal axis inhibition by negative feedback, causing adrenal suppression. (1) Adrenal crisis is diagnosed by an acute clinical decompensation, persistent hypotension that resolves with high dose steroid administration. (2) Adrenal crisis is precipitated by several causes such as illness, dehydration, trauma, emotional distress and sometimes due to no identifiable cause. (2) Clinical Case: 64-year-old male past medical history of lung carcinoma metastatic to mediastinum who presented to the hospital with tachycardia. On presentation, patient was tachycardic, tachypneic, and hypotensive. Labs significant for WBC 22, Na+ 129, K+ 3.2, Cr 3.4. Patient received 2.5 L bolus of NS and was given one dose of azithromycin due to concern for sepsis. After fluid resuscitation, hypotension and tachycardia resolved. Presenting symptoms included ongoing nausea, decreased appetite and malaise for several weeks. Repeat labs post fluid resuscitation showed resolution of leukocytosis, improvement of AKI, and repletion of electrolytes. CT chest abdomen pelvis showed questionable pneumonia, however, consolidations were difficult to distinguish from known malignant masses. Clinical picture was not consistent with pneumonia and so additional antibiotics were held. Several hours later, blood pressure decreased, and patient began requiring vasopressors. Cefepime was started given concern for septic shock. Nearly 48 hours after initiation of broad-spectrum antibiotics hypotension persisted and patient remained on vasopressors. Given clinical decline, etiology of shock was reconsidered. Patient reported daily prednisone use over the last several months for COPD management. Given high clinical suspicion of adrenal crisis in setting of chronic steroid use and glucocorticoid withdrawal, patient was started on hydrocortisone 100 mg every 8 hours. Shortly after initiation of stress dosed steroids, the patient was successfully weaned off vasopressors with complete resolution of hypotension. Conclusion: Presentation and symptoms of adrenal insufficiency and crisis including nausea, anorexia, fatigue, malaise, hypotension and electrolyte abnormalities are nonspecific, can go unrecognized and be masked by other disease processes, such as metastatic cancer. (1) Adrenal crisis is life threatening and must be diagnosed and treated early to prevent mortality. (2) Therefore, adrenal crisis should always be on the differential in patients who present with shock.

Local diagnostic reference level based on size-specific dose estimates: case of chest-abdomen-pelvis CT examination in a Moroccan hospital

This study aims to establish the local diagnostic reference levels for adult Chest-Abdomen-Pelvis (CAP)CT examination in a Moroccan hospital. DRLs were retrieved for the first time for CAP examination and were size-dependent. Data from 234 patients were collected retrospectively from one scanner for three months. CTDIvol, DLP and calculated SSDE were analyzed with IBM SPSS Statistics version 21. The proposed LDRLs in terms of CTDIvol, DLP and SSDE, the registered medians were 12.9 mGy, 849.3 mGy.cm and 18.16 mGy, respectively. Third quartile values were 15.65 mGy, 1014 mGy.cm and 20.75 mGy, respectively. The derived values were close to regional and international studies, with the exception of higher DLP quantity A comparison of CTDIvol and SSDE LDRLs has underlined the superiority of the SSDE. This result reflects from one side the morphologic nature of our small studied samplel. On the other side, the SSDE is correct for the misconception of the received dose, especially for lsimilar types of patients. The practice of the CAP CT examination has been studied and LDRLs related to DLP quantity revealed the necessity of application of radiation protection measures toward the length of scanned regions. On the other hand, LDRLs related to SSDE show an update of the received dose, higher than usually pretended using only CT outputs. Both results will lead practitioners to review the acquisition parameters and length of scanned regions and consider the patient’s morphology to reduce the dose received while keeping an interpretable exam.

Assessment of effective dose and cancer risk for pediatric chest and pelvis CT procedures in the central region of Saudi Arabia

BackgroundCT accounts for the highest radiation dose among various imaging modalities. Children are more susceptible to the harmful effects of radiation because of their higher cell-division rate and the likelihood of longer lifespans. Therefore, it is important to monitor pediatric CT doses to minimize their potential risks. AimThe objective of this study was to evaluate the radiation doses received by pediatrics undergoing trunk CT procedures and to estimate the associated cancer risk. MethodsA total of 255 pediatric patients who underwent chest (92 cases), abdomen & pelvis (133 cases), and chest-abdomen-pelvis (CAP) scans (30 cases) from hospitals within the central region of Saudi Arabia were categorized into four age groups: <1 year, 1–5 years, 6–10 years, and 11–15 years. The averages and ranges of DLP and CTDIvol from each procedure were measured and compared with international reports. The effective dose and cancer risk from each procedure were also reported. ResultsThe mean and range DLP (mGy.cm) for chest, abdomen & pelvis, and CAP examinations were found to be 131.5 (13.8–375.5), 244 (10.5–1353), and 94.2 (23.5–239), respectively. The mean and range CTDIvol (mGy) for chest, abdomen & pelvis, and CAP examinations were found to be 5.5 (1–33.8), 5.5 (0.9–18.6), and 3.6 (1.3–24.8) in order. The effective dose (mSv) and associated cancer risk (case/10,000 cases) for chest, abdomen & pelvis, and CAP ranges between (2.31–3.37; 1.27–1.85), (4.19–6.89; 2.30–3.78), and (1.89–3.58; 1.04–1.97), respectively. ConclusionEstimations of effective doses and cancer risk were conducted for pediatric patients aged <1 through 15 years who underwent chest, abdomen & pelvis, and CAP procedures. The documented dose levels in this study were relatively elevated compared to similar reports, revealing substantial variations even within the same procedure and age group category. Therefore, prioritizing dose optimization practices becomes crucial to mitigate potential radiation-induced cancer risks.

FRI500 Atypical Case Of Undifferentiated Shock

Abstract Disclosure: V. Vadini: None. P. Vasistha: None. Introduction: Shock is encountered frequently in the ICU. Undifferentiated shock, however, poses a diagnostic challenge. The differentials and work up are broad and time sensitive. Endocrinopathies are a known etiology but thyroid cardiomyopathy causing cardiogenic shock is rare. Clinical case: A 78 y old man presented to the ER with hypotension that did not improve after administration of 2.5 L IV fluids. Vasopressors were initiated and he was admitted to the ICU. Patient reported 2-month history of generalized weakness, nausea, vomiting, falls and poor oral intake. Review of systems was notable for 20-pound weight loss in 6 months, dyspnea with exertion, loss of appetite and occasional diarrhea. On exam, patient was afebrile, hypotensive 80/40, PR 87, O2 saturation &amp;gt; 90% on room air. He appeared pale with JVP measured at 11 cm of water. Pulse was irregular, heart sounds normal without murmurs. Bilateral lower extremities were mildly edematous. Strength in lower extremities was 4/5 proximal and distally. Labs were notable for normocytic anemia, troponin 1.05, elevated anion gap 18, lactate 1.8, creatinine 3.3 from a baseline of 1 and BNP 1425. ECG showed sinus rhythm with frequent premature atrial contractions. Chest Xray on admission was unremarkable. Additional labs were negative drug screen, normal cortisol, urinalysis. Blood cultures were sent. Overnight, the patient developed tachycardia and atrial fibrillation with rapid ventricular rate. Cardiology was consulted, bedside echo was suspicious for low left ventricular ejection fraction. The patient was anticoagulated with heparin. TSH was sent. He was requiring 2 vasopressors to maintain MAP&amp;gt;65. CT chest abdomen pelvis was unremarkable except stable pulmonary nodule. Patient became hypoxic on Day 2 of admission, CXR now showed features of pulmonary edema. TSH returned less than 0.01, free T4 4.69 Endocrinology was consulted, methimazole was started for thyrotoxicosis. Formal TTE showed LVEF 20-25% with global reduction in left ventricular contractility, dilated left atrium and mild MR. He was given furosemide for pulmonary edema. TSI and TRAB were positive indicating Grave’s disease. He was successfully transferred out of the ICU. Patient gradually became euvolemic with significant improvement in energy, appetite and functional capacity. He was able to participate in physical therapy and was eventually discharged to rehab. Conclusion: This case addresses an uncommon but potentially life-threatening cause of undifferentiated shock. Physical exam, history and high degree of suspicion are key in early identification and treatment. Although thyroid cardiomyopathy is rare, Grave’s disease is common and ruling our thyrotoxicosis should be included in preliminary work up of undifferentiated shock. Presentation: Friday, June 16, 2023

Establishment of diagnostic reference levels in computed tomography in two large hospitals in Oman.

This study aimed to estimate diagnostic reference levels (DRLs) for the most frequent computed tomography (CT) imaging examinations to monitor and better control radiation doses delivered to patients. Seven CT imaging examinations: Head, Chest, Chest High Resolution (CHR), Abdomen Pelvis (AP), Chest Abdomen Pelvis (CAP), Kidneys Ureters Bladder (KUB) and Cardiac, were considered. CT dosimetric quantities and patient demographics were collected from data storage systems. Local typical values for DRLs were calculated for CTDIvol (mGy), dose length product (DLP) (mGy·cm) and effective doses (mSv) were estimated for each examination. The calculated DRLs were given as (median CTDIvol (mGy):median DLP (mGy·cm)): Head: 39:657; Chest: 13:451; CHR: 6:228; AP: 12:578; CAP: 20:807; KUB: 7:315, and Cardiac: 2:31. Estimated effective doses for Head, Chest, CHR, AP, CAP, KUB and Cardiac were 1.3, 12.7, 6.3, 12.5, 18.1, 5.8 and 0.8mSv, respectively. The estimated DRLs will act as guidance doses to prevent systematic excess of patient doses.

Probability of induced cancers related to computed tomography examinations

Computed tomography (CT) is considered as one of the most used radiation imaging modalities, and CT procedures are increasing continuously all over the world, hence leading to considerable rise in cancers and radiation related diseases risk. This study was conducted in three general hospitals in Saudi Arabia, to analyze the associated radiation cancer risk from CT procedures. The collected data included the head chest, abdomen, abdomen pelvis (AP) and chest abdomen pelvis (CAP) procedures along with exposure parameter data (DLP and scan length). The risk of cancer was estimated by multiplying the effective dose with the risk coefficients obtained from ICRP 103. The mean DLP values were higher for females (647.5 ± 323.37 mGy cm) compared to male patients (587.7 ± 338.36 mGy cm), with no statistically significant differences (p = 0.497). The overall effective doses were 1.7 ± 0.53, 3.89 ± 1.22, 6.6 ± 4.23, 5.76 ± 3.28 and 10.75 ± 5.48 mSv for the head, chest, abdomen, abdomen pelvis (AP), and chest abdomen pelvis (CAP) procedures, respectively. The risk of cancer per procedure from head, chest, abdomen, AP and CAP procedures were found to be 6.96 × 10−5, 1.59 × 10−4, 2.71 × 10−4, 2.36 × 10−4, and 4.41 × 10−4, respectively. The effective doses and therefore the probability of cancer values were found to be within the range of other studies in the literature. However, dose optimization is always required, for the purpose of minimize the dose and cancer risk. Moreover, there is a clear need to improve awareness among radiology workers of unessential risks from suboptimal techniques in addition to applying the new imaging protocols in accordance with excellent practice around the world.

Abstract OT1-10-02: Trial of Neratinib Plus Capecitabine in Subjects With HER2-Negative Metastatic Breast Cancer With Brain Metastases and Abnormally Active HER2 Signaling

Abstract Background: Development of brain metastasis (BM) portends poor prognosis in patients (pts) with metastatic breast cancer (MBC) mainly due to lack of systemic therapy with strong activity in CNS. While survival in HER2+ BC BMs has improved due to development of various HER2 therapies with activity against BM, outcome for HER2- BC BMs remains dismal. A novel assay (CELsignia) which measures underlying HER2 signal (HS) of live cancer cells in response to HER2 agonists &amp; antagonists showed that about 25% of BC deemed HER2- by standard methods have underlying abnormal HS. Preclinical data showed various HER2 therapies inhibit tumor growth of such HER2- BC with abnormal HS. Among tested HER2 inhibitors with known CNS activity, neratinib had the lowest IC50. We propose a trial which identifies HER2- BC BM pts with abnormal HS &amp; assesses activity of neratinib based therapy. Design: This is a phase II single arm study with 2 steps- step 0 (biopsy) &amp; step 1 (treatment). Pts eligible for Step 0 will be registered as “Immediate Treatment (IT)” (intent to register to Step 1 immediately) or “Future Treatment” [registration can be delayed up to 28 weeks (wks)] &amp; undergo biopsy of most accessible extra CNS (eCNS) tumor. Tumor will be sent for CELsignia testing (2 wks turn around). Additional biopsies may be obtained for standard of care (SOC). IT pts can be treated with a brief course of capecitabine 1gm/m2 BID for 1 wk followed by 1 wk off while waiting for CELsigia result. Pts with BC having abnormal HS will be screened &amp; registered to step 1. Enrolled pts will receive neratinib 240mg daily (with SOC antidiarrheal prophylaxis) + capecitabine 750mg/m2 BID for 2 wks in every 3 wks cycle (C). Tumor assessments will be done prior to C3, 5 &amp; 7 then every 12 wks with MRI brain, CT chest abdomen pelvis &amp; bone scan using RECIST1.1 (eCNS disease) and a modified BM RANO criteria (&amp;gt;5mm, measurable disease, CNS). In isolated CNS progression, investigators have option of treatment beyond progression after SOC local treatment of progressing BMs. Key Eligibility Criteria: Step 0: Inclusion Criteria (IC): histologically confirmed HER2- BC (primary or metastatic); has radiological evidence of BM; prior treatment with CDK4/6 inhibitor + endocrine therapy required for hormone receptor+ BC, no prior specific treatment required for triple negative BC; radiological evidence of eCNS measurable disease (RECIST1.1) accessible for biopsy. Exclusion Criteria (EC): prior use of capecitabine in metastatic setting; known/suspected leptomeningeal disease. Step 1: IC: Abnormal HS; New or progressing BM that is measurable (&amp;gt;5mm); minimum washout periods in wks: last chemotherapy 2, hormonal therapy 1 except fulvestrant 4, targeted therapies 3, eCNS radiation 1, any investigational treatment 4. ECOG performance status 0-2; adequate end organ functions. EC: whole brain radiation in last 3 months (m). Endpoints: Co-primary: Overall survival (OS) and CNS progression free survival (CNS PFS). Key Secondary: Objective response rate, clinical benefit rate and duration of response (CNS using BM RANO, eCNS using RECIST1.1), eCNS PFS, various feasibility endpoints. Safety. Statistical methods: To detect 70% improvement in this trial in CNS PFS and OS compared to historical control (BEACON trial BM subset) 2.7m vs. 4.6m and 4.8m vs. 8.2 m with 80% power and 1-sided 5% significance level, a sample size of 22 is required. About 88 patients will undergo biopsy to enroll 22 pts in step 1. One futility assessment is planned when the first 12 pts have been treated for at least 6 wks or have failed (died or progressed) prior to 6 wks. If 9 or more in the first 12 have died or progressed by 6 wks of treatment, the study will close for futility. PFS and OS will be analyzed using Kaplan-Meier survival functions. Contact: Ajay Dhakal MBBS, ajay_dhakal@urmc.rochester.edu NCT#: NCT04965064 Funding: Celcuity, Puma Biotechnology Status: IRB approved. Anticipated activation Aug 2022, Accrual duration: 2 years. Seeking participating sites. Citation Format: Ajay Dhakal, Ruth O’Regan, Carla Falkson, David Hicks, Douglas Hawkins, Bradley Turner, Nimish Mohile. Trial of Neratinib Plus Capecitabine in Subjects With HER2-Negative Metastatic Breast Cancer With Brain Metastases and Abnormally Active HER2 Signaling [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-10-02.

Patient dose reduction for a localizer radiograph with an additional tin filter in chest-abdomen-pelvis, spine, and head computed tomography examinations.

This study aimed to evaluate the dose reduction potential of adding a tin filter to localizer radiographs (LR) on computed tomography (CT) examinations in both phantom and clinical studies. LRs were performed using combinations of 120 kVp and 20mA (120/20), 100 kVp with a tin filter, and 50mA or 20mA (Sn100/50, Sn100/20). For the phantom experiment, entrance surface doses (ESD) of the LRs were evaluated for each protocol using an anthropomorphic phantom. This retrospective clinical study included 700 patients (300 for chest-pelvis, 200 for spine, and 200 for head CTs). The volume CT dose indices (CTDIvols) of the main CT scans were recorded and placed into one of three groups based on body mass index (BMI): underweight, normal-weight, and overweight, to evaluate the effect of LR acquisition conditions on the performance of the automatic tube current modulation technique of subsequent CT scans. The ESDs of all LRs with the Sn100/50 protocol were 0.03mGy, a decrease of more than 80% compared to those of the 120/20 protocol. Moreover, the Sn100/20 protocol reduced ESD to 0.02mGy. In chest-pelvis CT, there were no significant differences in the CTDIvol between with and without a tin filter for each BMI group. However, the lateral LRs with the tin filter on the spine CT slightly reduced the CTDIvol in normal-weight and overweight patients. Although there is room to optimize the acquisition conditions for larger patients, an additional tin filter for LR is a useful means to efficiently reduce ESDs.

LBODP066 A Conservative Approach To The Management Of Glucagon Receptor (GCCR) Mutation (Mahvash Syndrome)

Abstract Background Mahvash Syndrome a rare autosomal recessive cause of pancreatic neuroendocrine tumors (pNET) results from inactivation of GCCR. Clinically it presents with hyperglucagonemia without glucagonoma syndrome. Since described in 2008 all surviving adult cases have been managed surgically. We describe 2 related cases managed medically. Case 1 In 2015 a 52 year old female with history of an enlarged pancreas (Aunt of Case 2) presented with incidentally identified hypovascular pancreatic masses while being assessed for back pain. An EBUS-guided FNA of the pancreas demonstrated a pNET with elevated serum glucagon of 100,991 pmol/ml, and Chromogranin A of 183 ng/ml but normal C-peptide, insulin, glucose, and HbA1C. CT chest abdomen pelvis, and octreotide scan had no evidence of metastasis. Due to vague abdominal discomfort, persistently high glucagon levels and pruritis without rash she was started on somatostatin analog therapy. Given her high glucagon without glucagonoma syndrome she was referred to genetics for GCCR sequencing which was notable for homozygous c.187G&amp;gt;A p. Asp63Asn variant (subsequently reclassified as pathogenic). Her case was also reviewed at the multidisciplinary tumor board given her dominant but stable conglomerate 3.2×1.7cm pancreatic lesion (individually measuring 1.6 and 1.4cm). Continued SSA for 7 years showed a slow change in size of the pNET with the dominant lesion at the pancreatic head (1.8cm from 1.6cm in 2015), with no evidence of metastatic spread or clinical changes. Case 2 a 46 year old man with IBD and Psoriatic Arthritis, presented in 2010 with choledocholithiasis. Imaging identified a bulky pancreas with a 1.2 cm nodule consistent with a neuroendocrine tumor. His investigations included 5HIAA, Gastrin, Prolactin, Chromogranin A, Insulin, Fasting Glucose, and HgbA1C all of which were normal. In 2015 following identification of an Aunt (Case 1) with a GCCR Variant of Uncertain Significance his glucagon level was found to be above the limit of detection for the assay. Given his preferences and lack of symptoms, he was monitored clinically without surgery or medications. His Glucagon levels have remained stably elevated at 12940 pg/ml, and the initial pNET has slowly progressed to 1.3cm with an additional 1.1cm and 0.5cm pNETs identified over a 7 year interval. Conclusion These cases describe 2 patients with homozygous c.187G&amp;gt;A GCCR variants, resulting in Mahvash Syndrome. In contrast to previously published cases of the syndrome, and specifically the case report with the same variant, they have been managed non-surgically with regular imaging, and in Case 1 with SSA therapy. While there has been slow growth of the underlying pNET, there has been no clinical changes or evidence of metastatic disease, providing insight into the natural history of Mahvash Syndrome caused by c.187G&amp;gt;A variant, and possibly supporting a less aggressive clinical approach. Presentation: No date and time listed

Are Diagnostic Computed Tomography Chest Scans Sufficient for Detecting Supraclavicular in Initial Breast Cancer Staging?

<h3>Purpose/Objective(s)</h3> Initial staging workup strategies for locally advanced or suspected stage IV breast cancer can include computed tomography (CT) of the chest, abdomen, pelvis (CAP) and bone scan or, alternatively, a whole-body positron emission tomography/computed tomography (PET/CT). Variations in intravenous contrast injection site and bolus timing, arm positioning, and acquisition techniques on a CT chest scan could limit visualization of supraclavicular (SCV) and supracricoid cervical lymph nodes, which are critical for staging, prognosis, and treatment recommendations. The study's purpose is to determine whether there is a difference between the incidences of SCV and cervical lymphadenopathy detected on staging CT CAP versus PET/CT scans. <h3>Materials/Methods</h3> The records of consecutive newly diagnosed breast cancer patients who received initial staging scans at a single institution from 2012 to 2017 were reviewed in a HIPAA compliant, institutional review board-approved study. De-identified information was reviewed for inclusion: new breast cancer diagnosis, >18 years old, and availability of staging. Exclusion criteria were prior breast cancer treatment, re-staging for known recurrence, and nondiagnostic imaging examinations. Radiology reports were searched for SCV and cervical lymphadenopathy to determine the incidence detected by each imaging modality. A board certified neuroradiologist reviewed and characterized scans that noted cervical or SCV lymphadenopathy. <h3>Results</h3> The initial search resulted in 3,126 PET/CT and 631 CT CAP scans with 588 patients fulfilling the inclusion criteria. PET/CT scans had been performed in 539 patients and 49 received CT CAP and bone scans. The two groups were well matched by stage (Table 1). Metastatic cervical lymphadenopathy was detected by PET-CT in 50 patients (7.9%) versus two (3.7%) with CT CAP. Out of the 50 patients who had cervical lymphadenopathy detected by PET-CT, 30 (60%) had metastatic cervical lymphadenopathy above the level of the lung apex, the typical upper extent of a CT chest field of view. Although 25 (50%) patients had additional areas of distant metastatic disease, cervical lymphadenopathy above the thoracic inlet was the only site of distant metastasis for 13 patients (26%), and would not have been detectable by CT CAP. <h3>Conclusion</h3> PET/CT detected more cervical and SCV lymphadenopathy than CT CAP in initial staging scans for breast cancer, with 60% of those detected on PET/CTs in areas that would have been occult on standard CT chest scans. Such nodal involvement constituted the only site of distant metastatic disease in 26% of the patients. Thus, dedicated CT neck imaging may be a reasonable addition to CT CAP as an initial staging strategy to determine accurate staging and radiation treatment field volumes and borders.

Assessment of organ and effective doses received by adult patients undergoing computed tomography in three hospitals in Brazzaville, Congo Republic.

The present study aimed to evaluate adult patient data collected from three hospitals in Brazzaville, Congo Republic, for the purpose of estimating organ and effective doses for each included examination type. A total of 1277 adult patients (aged 16-97years) who underwent head, chest, abdominopelvic (AP), chest-abdomen-pelvis (CAP), and lumbar spine computed tomography scans were considered. The organ and effective doses were estimated using a Monte Carlo-based method. The effective doses were also determined using k-factors. In general, the organ and effective doses estimated in this study were higher than those reported in the literature. The k-factor method underestimated the effective dose by up to 65.9%. This study demonstrates that urgent steps should be taken to reduce doses administered to patients to optimal levels. Such optimal levels may be achieved by adopting local diagnostic reference levels, together with the implementation of dose reduction strategies.

Establishing diagnostic reference levels for CT examinations in the south region of Saudi Arabia

This study aims to establish local diagnostic reference levels (DRLs) for the most common computed tomography (CT) examinations in the southern region of Saudi Arabia. Data has been collected from 399 adult patients (234 males and 165 females) and 76 paediatric patients (51 males and 25 females) undergoing different CT procedures. These procedures are as follows: CT chest (adults: 107, paediatrics: 10), abdomen (adults: 121, paediatrics: 11), pelvis (adults: 74), brain (adults: 48, paediatrics: 55), abdominopelvic (AP) (adults: 17), liver Tri-phase (adults: 12), and chest abdomen pelvis (CAP) CT scan (adults: 20). For adult patients, the CTDIvol for chest, abdomen, pelvis, brain, AP, CAP, and liver tri-phase procedures ranged from 3.74 to 22.61 mGy, 2.52–51.40 mGy, 9.53–38.63 mGy, 5.72–5109.0 mGy, 2.54–17.16 mGy, 3.93–29.14 mGy, and 12.35–40.55 mGy, respectively. Similarly, CTDIvol for chest, abdomen, and brain paediatric procedures ranged from 3.15 to 5.25 mGy, 3.23–224.32 mGy, and 16.47–109.08 mGy, respectively. For adult patients, the study observed that dose length product for chest, abdomen, pelvis, brain, AP, CAP, and liver tri-phase procedures ranged from 136.50 to 1124.13 mGy cm, 137.70–1403.66 mGy cm, 244.14–1205.30 mGy cm, 98.20–1163.0 mGy cm, 6.43–893.60 mGy cm, 284.10–2216.70 mGy cm, and 415.20–2055.90 mGy cm, respectively. Similarly, dose length product for chest, abdomen, and brain paediatrics procedures ranged from 122.81 to 175.34 mGy cm, 5.34–553.51 mGy cm, and 333.60–2084.0 mGy cm, respectively. Radiation doses varied between hospitals, with wide variation in technical settings suggesting an urgent need for establishing a national DRL as a necessary part for dose optimisation.

IgG kappa multiple myeloma with isolated central nervous system relapse.

A 76-year-old male presented with acute renal failure and cast nephropathy was diagnosed with IgG kappa multiple myeloma (MM). His paraprotein was 40 g/L, kappa-free light chain level was 17,058 mg/L, kappa: lambda light chain ratio was 1445. An automated full blood count showed hemoglobin 90 g/L, white blood cells 2.96 × 109/L, neutrophil 1.7 × 109/L, and platelet 179 × 109/L. Bone marrow trephine sample was hypercellular with nearly 100% plasma cells, which were positive for CD138, CD56, and cyclin D1, and showed kappa light chain restriction. Fluorescence in situ hybridization analysis with dual color/dual probes for immunoglobulin heavy chain (IGH) and MYC genes (Cytocell) and whole genome screening using 8 × 60K oligonucleotide arrays (Agilent) performed on the CD138 enriched cells (CD138 microbeads Miltenyi Biotech) from the liquid bone marrow sample showed no evidence of IGH rearrangement, MYC rearrangement, 1q gain, 1p loss, 17p loss, or any clinically significant imbalance. He was treated with eight cycles of bortezomib, cyclophosphamide, and dexamethasone (VCD) to very good partial response. He relapsed 30 months after diagnosis with paraprotein of 36 g/L, kappa light chains of 10,000 mg/L, and creatinine of 498 μmol/L. He was treated with eight cycles of bortezomib, thalidomide, and dexamethasone (VTD) to paraprotein undetectable and kappa light chain 29 mg/L. Seven months post completion of VTD (4 years after myeloma diagnosis), he presented with abnormal gait, falls, and a left-sided facial droop. His paraprotein was 2 g/L and serum-free kappa light chain was 81 mg/L. Magnetic resonance imaging (MRI) head and whole spine showed multifocal diseases in spinal canal and intracranially, involving the cranial nerves most prominent the fifth, seventh, eighth, and hypoglossal nerve on the left, anterior surface of the inferior pons medulla (Figure 1A). There were multiple lesions in the cervical spine as well as in the thoracic spine (Figure 1B). Computerized tomography (CT) chest abdomen pelvis did not show the evidence of other new diseases. Plasma cells were detected in cerebral spinal fluid (CSF) (Figure 1C, May–Grünwald–Giemsa stain x100 objective). He was treated with pomalidomide and dexamethasone. Weekly cytarabine intrathecal (IT) treatment was given until the clearance of plasma cells from CSF samples for three times. Four months later, he achieved the complete remission on MRI head and whole spine with undetectable paraprotein and normal light chain ratio. Serial MRI scans confirmed ongoing remission. A year later, he relapsed again with worsening mobility and reappearance of myeloma cells in CSF. By flow cytometry, these cells were positive for CD138, CD38, CD56, CD117, and negative for CD19. MRI head showed leptomeningeal disease with a new 2.2 cm frontal lobe lesion. His paraprotein remained undetectable and kappa light chain remained at below 100 mg/L. He continued systemic pomalidomide and dexamethasone chemotherapy and received palliative whole brain radiotherapy 20 Gy in 5 fractions for symptom control. His disease continued progressing and he passed away 3 months later (5.5 years after myeloma diagnosis). Here, we reported a myeloma patient with isolated CNS relapse, who achieved 1 year of remission with combination of intrathecal chemotherapy and systemic pomalidomide and dexamethasone treatment, but sadly passed away 4 months after second CNS relapse. CNS MM is a rare form of extramedullary disease, but carries a very poor prognosis. The optimal approach to treatment of CNS MM is not currently known. The current approach includes systemic therapy with agents known to cross the blood brain barrier, intrathecal therapy, and CNS irradiation. Innovative approach to treatment is urgently needed. The authors received no specific funding for this work. Ke Xu and Lucy Kamuriwo wrote the manuscript. Ke Xu, Lucy Kamuriwo, Claire Anderson and Parag Jasani critically revised the final version of the manuscript. The authors declare they have no conflicts of interest. No written or verbal consent obtained from patient. Patient has passed away.

National diagnostic reference levels based on clinical indications and patient size for adults’ computed tomography in the Kingdom of Bahrain

PurposeThe study aims to establish national diagnostic reference levels (NDRLs) for computed tomography (CT) examinations performed on adult patients based on clinical indications, patient gender, and size in the Kingdom of Bahrain. MethodsThe volume CT dose index (CTDIvol) and dose length product (DLP) were collected between September 2020 and September 2021 from 63% of the total number of CT scanners in the country (five out of eight CT scanners). The data were collected from at least ten patients for eight common clinical indications in the head, abdomen-pelvis and chest-abdomen-pelvis (CAP) regions. The NDRLs were calculated for each clinical indication as the third quartile of the CT scanners' median values of CTDIvol and DLP. They were also calculated based on the patient's gender (for the head) and their size (for the abdomen-pelvis and CAP clinical indications). ResultsFrom 1665 CT examinations, the NDRLs in term of CTDIvol were 67, 66, 67, 13, 14, 17, 19, and 15 mGy for symptoms of headache, trauma, stroke, flank pain, renal colic, abdominal pain, diverticulitis/appendicitis and oncologic follow-up, respectively. Likewise, these were 1206, 1286, 1152, 690, 779, 972, 1061, 1073 mGy cm in terms of DLP, respectively. For large size patients, NDRLs in terms of CTDIvol were on average 1.7 times higher than those from medium size patients for all the clinical indications in the abdomen-pelvis and CAP regions. ConclusionThe NDRLs were established for the most common clinical indications in the Kingdom of Bahrain. They are higher than those established in the literature, thus emphasizing the urgent need of an optimization strategy for better patient radiation protection.

Assessment of Organ and Effective Doses Received by Paediatric Patients Undergoing Computed Tomography Examinations in Three Hospitals in Brazzaville, Congo Republic: An Urgent Necessity for Regulatory Control

The present study aimed at estimating organ and effective doses from computed tomography (CT) scans of paediatric patients in three hospitals in Brazzaville, Congo Republic. A total of 136 data on paediatric patients, from 0.25 (3 months) to 15 years old, who underwent head, chest, abdomen – pelvis (AP) and chest – abdomen – pelvis (CAP) CT scans was considered. The approach followed in the present study to compute organ doses was to use pre-calculated volume CT dose index (CTDIvol) – and 100 milliampere-second (mAs) – normalized organ doses determined by Monte Carlo (MC) simulation. Effective dose were then derived using the international commission on radiological protection (ICRP) publications 60 and 103 formalism. For comparison purposes, effective dose were also computed using dose-length product (DLP) – to – effective dose conversion factors. A relatively high variation in organ and effective doses was observed in each age group due to the dependence of patient dose on the practice of technicians who perform the CT scan within the same facility or from one facility to another, patient size and lack of adequate training of technicians. In the particular case of head scan, the brain and the eye lens were delivered maximum absorbed doses of 991.81 mGy and 1176.51 mGy, respectively (age group 10-15 y). The maximum absorbed dose determined for the red bone marrow was 246.08 mGy (age group 1-5 y). This is of concern as leukaemia and brain tumours are the most common childhood cancers and as the ICRP recommended absorbed dose threshold for induction of cataract is largely exceeded. Effective doses derived from MC calculations and ICRP publications 60 and 103 tissues weighting factors showed a 0.40-17.61 % difference while the difference between effective doses derived by the use of k- factors and those obtained by MC calculations ranges from 0.06 to 224.87 %. The study has shown that urgent steps should be taken in order to significantly reduce doses to paediatric patients to levels observed in countries where dose reduction techniques are successfully applied.

EXTRAMEDULLARY PULMONARY PLASMACYTOMA AS A COMPLICATION OF RELAPSED MULTIPLE MYELOMA

TOPIC: Pulmonary Manifestations of Systemic Disease TYPE: Fellow Case Reports INTRODUCTION: Extramedullary plasmacytoma (EMP) are rare manifestations of multiple myeloma (MM). We report a case of pulmonary EMP presenting as hilar mass. CASE PRESENTATION: A 51 year old female presented with hearing loss and right facial palsy. Medical history was significant for MM diagnosed 2 years prior, treated with bortezomib-prednisone therapy. 6 months ago, thoracic spine plasmacytoma were found requiring surgical resection and local radiation. Remission was perceived and she was maintained on Thalidomide. MRI brain and spine revealed meningeal enhancement with lytic bony lesions, concerning for metastatic disease. CT chest abdomen pelvis revealed a 4.5 x 5.5 cm right hilar mass with complete right lower lobe (RLL) bronchus occlusion, post-obstructive pneumonia, right pleural effusion, pleural thickening and nodularity. She underwent bronchoscopy with endobronchial biopsy of RLL bronchial nodules and EBUS guided transbronchial needle aspiration of right hilar mass. Pathology was consistent with plasma cell myeloma with plasmablastic features. Given her MM history and absence of EBV, primary plasmablastic lymphoma was less likely. A bone marrow biopsy showed >10% myeloma cells, thus her diagnosis was consistent with relapsed MM with extramedullary plasmacytoma (EMP) rather than primary pulmonary plasmacytoma (PPP). Subsequently she underwent systemic and intrathecal second line chemotherapy, but her course was complicated by rapidly progressive refractory disease and patient chose to pursue hospice care. DISCUSSION: EMP are seen in 7 % patients with MM at the time of diagnosis, whereas another 6% develop it later in the course of illness; these portend poor prognosis. Among them, pulmonary EMP are extremely rare. Other pulmonary complications of multiple myeloma include pneumonia, including organizing pneumonia like consolidation, multiple pulmonary nodules, interstitial infiltrates and pleural thickening and effusion. In contrast, primary solitary extramedullary plasmacytoma is a rare discrete plasma cell neoplasm within soft tissue, without bone marrow involvement or other systemic features of MM. They commonly occur in the aero-digestive tract, of which solitary PPP is a rare type. PPP have better prognosis and longer survival rates compared to EMP associated with MM. Their management also differs, EMP associated with MM are treated aggressively with chemotherapy and local radiation or surgery as needed, whereas solitary PPP are treated with radiation only. CONCLUSIONS: Knowledge of pulmonary EMP and its clinical course is important for physicians, such that the etiology of pulmonary abnormalities in patients with multiple myeloma are evaluated and determined in order to ensure appropriate therapy and patient counseling. REFERENCE #1: Bladé J, et al. Soft-tissue plasmacytomas in multiple myeloma: incidence, mechanisms of extramedullary spread, and treatment approach. J Clin Oncol. 2011;29(28):3805-3812 REFERENCE #2: Varettoni M, Corso A, Pica G, Mangiacavalli S, Pascutto C, Lazzarino M. Incidence, presenting features and outcome of extramedullary disease in multiple myeloma: a longitudinal study on 1003 consecutive patients. Ann Oncol. 2010;21(2):325-330. doi:10.1093/annonc/mdp329 REFERENCE #3: Prasad R, Verma SK, Sodhi R. Multiple myeloma with lung plasmacytoma. Lung India. 2011 Apr-Jun; 28(2): 136-138. DISCLOSURES: No relevant relationships by Jyotirmayee Lenka, source=Web Response No relevant relationships by Naman Sharma, source=Web Response

Potential Clinical Utility of a Targeted Circulating Tumor DNA Assay in Esophageal Adenocarcinoma.

Objective:To explore the clinical utility of circulating tumor DNA (ctDNA) in esophageal adenocarcinoma (EAC) by developing a cost-effective and rapid technique utilising targeted amplicon sequencing.Summary of background data:Emerging evidence suggests that levels of ctDNA in the blood can be used to monitor treatment response and in the detection of disease recurrence in various cancer types. Current staging modalities for EAC such as computerised tomography of the chest/abdomen/pelvis (CT) and positron emission tomography (PET) do not reliably detect occult micro-metastatic disease, the presence of which signifies a poor prognosis. After curative-intent treatment, some patients are still at high risk of recurrent disease, and there is no widely accepted optimal surveillance tool for patients with EAC.Methods:Sixty-two patients with EAC were investigated for the presence of ctDNA using a tumor-informed approach. We designed a custom targeted amplicon sequencing panel of target specific primers covering mutational foci in 9 of the most commonly mutated genes in EAC. Serial blood samples were taken before and after neoadjuvant treatment (NAT), and during surveillance.Results:Somatic mutations were detected in pre-treatment biopsy samples of 55 out of 62 (89%) EAC patients. Mutations in TP53 (80%) were the most common. Out of these 55 patients, 20 (36%) had detectable ctDNA at baseline. The majority (90%) of patients with detectable ctDNA had either locally advanced tumors, nodal involvement or metastatic disease. In patients with locally advanced tumors, disease free survival (DFS) was more accurately stratified using pre-treatment ctDNA status [HR 4.34 (95% CI 0.93–20.21); P = 0.05] compared to nodal status on PET-CT. In an exploratory subgroup analysis, patients who are node negative but ctDNA positive have inferior DFS [HR 11.71 (95% CI 1.16-118.80) P = 0.04]. In blood samples taken before and following NAT, clearance of ctDNA after NAT was associated with a favourable response to treatment. Furthermore, patients who are ctDNA positive during post-treatment surveillance are at high risk of relapse.Conclusions:Our study shows that ctDNA has potential to provide additional prognostication over conventional staging investigation such as CT and PET. It may also have clinical utility in the assessment of response to NAT and as a biomarker for the surveillance of recurrent disease.

Spectral augmentation for heart chambers segmentation on conventional contrasted and unenhanced CT scans: an in-depth study.

Recently, machine learning has outperformed established tools for automated segmentation in medical imaging. However, segmentation of cardiac chambers still proves challenging due to the variety of contrast agent injection protocols used in clinical practice, inducing disparities of contrast between cavities. Hence, training a generalist network requires large training datasets representative of these protocols. Furthermore, segmentation on unenhanced CT scans is further hindered by the challenge of obtaining ground truths from these images. Newly available spectral CT scanners allow innovative image reconstructions such as virtual non-contrast (VNC) imaging, mimicking non-contrasted conventional CT studies from a contrasted scan. Recent publications have demonstrated that networks can be trained using VNC to segment contrasted and unenhanced conventional CT scans to reduce annotated data requirements and the need for annotations on unenhanced scans. We propose an extensive evaluation of this statement. We undertake multiple trainings of a 3D multi-label heart segmentation network with (HU-VNC) and without (HUonly) VNC as augmentation, using decreasing training dataset sizes (114, 76, 57, 38, 29, 19 patients). At each step, both networks are tested on a multi-vendor, multi-centric dataset of 122 patients, including different protocols: pulmonary embolism (PE), chest-abdomen-pelvis (CAP), heart CT angiography (CTA) and true non-contrast scans (TNC). An in-depth comparison of resulting Dice coefficients and distance metrics is performed for the networks trained on the largest dataset. HU-VNC-trained on 57 patients significantly outperforms HUonly trained on 114 regarding CAP and TNC scans (mean Dice coefficients of 0.881/0.835 and 0.882/0.416, respectively). When trained on the largest dataset, significant improvements in all labels are noted for TNC and CAP scans (mean Dice coefficient of 0.882/0.416 and 0.891/0.835, respectively). Adding VNC images as training augmentation allows the network to perform on unenhanced scans and improves segmentations on other imaging protocols, while using a reduced training dataset.

DERIVATION OF LOCAL DIAGNOSTIC REFERENCE LEVELS FOR COMMON ADULT COMPUTED TOMOGRAPHY EXAMINATIONS IN MOROCCAN HOSPITAL.

The purpose was to derive local diagnostic reference levels (LDRLs) for adults common computed tomography (CT) examinations in Moroccan hospital. The data of patients were collected retrospectively from one facility for 2 months period. The proposed LDRLs were defined as 75th percentile of spreads for CT dose index-volume (CTDIvol) and dose length product (DLP). Findings were compared with diagnostic reference levels (DRLs) of France, Australia and Egypt. A total of 259 cases were enrolled including 53% of male and 47% of female. The corresponding LDRLs in terms of CTDIvol (mGy) were 58, 15, 15 and 14 for head, chest, abdomen-pelvis and chest-abdomen-pelvis CT examinations, respectively. For DLP (mGy.cm) were 1298, 944, 1874 and 2026, respectively. The proposed LDRLs for CTDIvol were almost similar to DRLs of Australia, higher than those of France and lower than Egyptian DRLs. In terms of DLP, LDRLs were higher than compared studies with exception of head CT, which were lower and higher for CTDIvol than Egyptian DRLs. The results highlight higher radiation doses during adult CT scans, indicating the need to spread the same investigation regarding other imaging procedures including different radiological examinations across Moroccan hospitals.