Effective doses in radiology and diagnostic nuclear medicine: a catalog

Diagnosis and Treatment of Primary Tracheobronchial Tumors

BACKGROUND

Primary tracheobronchial tumors (PTBTs) are rare but life-threatening, accounting for approximately 0.2% of all respiratory neoplasms. Owing to their nonspecific clinical symptoms, PTBTs are often initially misdiagnosed as bronchial asthma or bronchitis in the early stages. In addition, standardized treatments for PTBTs are currently lacking.

AIMS

This study aimed to provide a comprehensive review of this diagnostic challenge and treatment modalities of PTBTs.

METHODS

Drawing on the latest literature and clinical guidelines, we carried out a comprehensive and systematic analysis of PTBTs, focusing on diagnostic modalities, and evidence-based treatment options.

RESULTS AND CONCLUSIONS

Primary diagnostic methods for PTBTs include pulmonary function tests, chest radiography, computed tomography, and fiberoptic bronchoscopy. Computed tomography, and fiberoptic bronchoscopy may be the most valuable diagnostic tools for patients with PTBTs or those highly suspected of having PTBTs. Currently, there are no consensus guidelines for PTBTs, and surgery is the most effective method for treating PTBTs if the patients have indications for surgery. In addition, radiotherapy, chemotherapy and interventional therapy may be useful complementary treatments for inoperable patients. Immunotherapy may be a significant management strategy for PTBTs in the future. Further researches should concentrate on both the early identification and enhanced therapeutic management of these tumors to improve survival and diminish morbidity and mortality rates by investigating the optimal design of systematic therapy.

Detection of Pulmonary Nodules on Ultra-low Dose Chest Computed Tomography With Deep-learning Image Reconstruction Algorithm

PURPOSE

To evaluate the accuracy of ultra-low dose (ULD) chest computed tomography (CT), with a radiation exposure equivalent to a 2-view chest x-ray, for pulmonary nodule detection using deep learning image reconstruction (DLIR).

MATERIAL AND METHODS

This prospective cross-sectional study included 60 patients referred to our institution for assessment or follow-up of solid pulmonary nodules. All patients underwent low-dose (LD) and ULD chest CT within the same examination session. LD CT data were reconstructed using Adaptive Statistical Iterative Reconstruction-V (ASIR-V), whereas ULD CT data were reconstructed using DLIR and ASIR-V. ULD CT images were reviewed by 2 readers and LD CT images were reviewed by an experienced thoracic radiologist as the reference standard. Quantitative image quality analysis was performed, and the detectability of pulmonary nodules was assessed according to their size and location.

RESULTS

The effective radiation dose for ULD CT and LD CT were 0.13±0.01 and 1.16±0.6 mSv, respectively. Over the whole population, LD CT revealed 733 nodules. At ULD, DLIR images significantly exhibited better image quality than ASIR-V images. The overall sensitivity of DLIR reconstruction for the detection of solid pulmonary nodules from the ULD CT series was 93% and 82% for the 2 readers, with a good to excellent agreement with LD CT (ICC=0.82 and 0.66, respectively). The best sensitivities were observed in the middle lobe (97% and 85%, respectively).

CONCLUSIONS

At ULD, DLIR reconstructions, with minimal radiation exposure that could facilitate large-scale screening, allow the detection of pulmonary nodules with high sensitivity in an unrestricted BMI population.

US-Guided percutaneous core needle biopsy via the complete transhepatic approach: a reliable option for deep abdominal lesions

PURPOSE

To assess the feasibility, reliability, and diagnostic performance of ultrasound (US)-guided percutaneous core needle biopsy (PCNB) performed via the complete transhepatic approach (CTHa) for abdominal lesions.

MATERIALS AND METHODS

This study included 71 patients (31 males, 40 females) with a mean age of 64.8 ± 13.9 years (range: 19-93) who underwent US-guided PCNB via the CTHa for abdominal lesions between January 2014 and December 2024. All biopsies were performed by interventional radiologists with at least five years of experience using a coaxial system and an 18-gauge automatic biopsy device. Patients were assessed for technical success, diagnostic yield, and complications, which were classified as major or minor based on the Society of Interventional Radiology (SIR) guidelines.

RESULTS

Tissue samples were successfully obtained in all cases, achieving a 100% technical success rate. Adequate material for pathological diagnosis was available in 63 of 71 patients (88.7%), while a definitive diagnosis could not be established in 11.3% of cases. Diagnostic yield was significantly influenced by lesion type (solid or mixed with cystic components) and anatomical location (p = 0.001 and p = 0.032, respectively). Complications occurred in 12.7% of patients, including 11.3% minor and 1.4% major complications. Univariate logistic regression analysis identified a history of malignancy, lesion size along the biopsy path, and the length of liver parenchyma traversed as significant predictors of complications (p = 0.012, 0.027 and 0.003 respectively). In the multivariate model, liver parenchyma length remained the only independent risk factor (p = 0.023).

CONCLUSION

US-guided PCNB via the CTHa is a safe and effective option for abdominal lesions when extrahepatic access is not feasible. While longer liver tissue traversal increases the risk of minor complications, no major adverse events were observed. Careful procedural planning and consideration of lesion location and cystic content are essential to optimize diagnostic yield.

Feasibility of an Ultra-Low-Dose PET Scan Protocol with CT-Based and LSO-TX-Based Attenuation Correction Using a Long-Axial-Field-of-View PET/CT Scanner

Long-axial-field-of-view (LAFOV) PET scanners enable substantial reduction in injected radiotracer activity while maintaining clinically feasible scan times. Whole-body CT scans performed for PET attenuation correction can significantly add to total radiation exposure. We investigated the feasibility of an ultra-low-dose PET protocol and the application of a CT-less PET attenuation correction method (lutetium oxyorthosilicate background transmission [LSO-TX]) that uses 176Lu background radiation from detector scintillators with low-count PET data. Methods: Each of the 4 study subjects was scanned for 90 min using an ultra-low-dose 18F-FDG protocol (injected activity, 6.7-9.0 MBq) with an LAFOV PET scanner. PET images were reconstructed with different frame durations using low-dose CT-based and LSO-TX-based attenuation maps (μ-maps). The image quality of PET images was assessed by the signal-to-noise ratio (SNR) in the liver and the contrast-to-noise ratio in the brain. Absolute errors in SUVs between PET images reconstructed with LSO-TX-based and CT-based μ-maps were assessed at each scan duration. Results: Visual assessment showed that 20-30 min of PET data obtained using 18F-FDG activities below 10 MBq (i.e., 0.1 MBq/kg) can yield high-quality images. PET images reconstructed with CT-based and LSO-TX-based μ-maps had comparable SNRs and contrast-to-noise ratios at all scan durations. The mean ± SD SNRs of PET images reconstructed with the CT-based and the LSO-TX-based μ-maps were 9.2 ± 1.9 dB and 9.8 ± 2.0 dB at 90-min scan duration, 6.8 ± 1.7 dB and 6.9 ± 1.8 dB at 30-min scan duration, and 5.5 ± 1.2 dB and 5.6 ± 1.2 dB at 20-min scan duration, respectively. The relative absolute SUV errors between PET images reconstructed with LSO-TX-based and CT-based μ-maps ranged from 3.1% to 6.4% across different volumes of interest with a 20-min scan duration. Conclusion: PET scans with an LAFOV scanner maintained good visual image quality with 18F-FDG activities below 10 MBq for scan durations of 20-30 min. The LSO-TX-based attenuation correction method yielded images comparable to those obtained with the CT-based attenuation correction method in such protocols.

Radiation in the Bronchoscopy Suite: One Center's Experience With Navigational Bronchoscopy and a Review of the Literature

BACKGROUND

This study aimed to quantify radiation doses during navigational bronchoscopy procedures, comparing them with reported cohorts and evaluating the LungVision (Body Vision Medical Inc.) system's efficacy in dose reduction.

METHODS

This retrospective observational study included 52 consecutive navigational bronchoscopy cases, categorized into 4 imaging groups based on the C-arm: Cios Spin (Siemens Healthineers), or OEC 9900 (GE HealthCare); and the 3D tomographic imaging algorithm: Cios Spin's onboard imaging, or LungVision's AI-driven imaging. Patient and lesion data, outcomes, and radiation indices were collected. Existing literature on 3D image guidance for bronchoscopic lung nodules was reviewed to compare reported radiation doses.

RESULTS

Combining LungVision with Cios Spin significantly reduced radiation dose in all cases compared with using Cios Spin alone: Cumulative air kerma (Ka,r) reduced from 238.7 to 119.1 mGy (P=0.03), and air kerma-area product (KAP) decreased from 28.19 to 15.09 Gy·cm2 (P=0.03). For biopsy cases, LungVision led to notable dose reductions: Ka,r of 279 to 129.1 mGy, and KAP of 30.70 to 16.27 Gy·cm2. LungVision notably reduced radiation indices in 7 paired spins, isolating the 3D imaging algorithm as the sole variable with the same Cios Spin C-arm. A literature review provides additional context on radiation for bronchoscopic biopsies.

CONCLUSION

Following the "as low as reasonably achievable" (ALARA) principle minimizes ionizing radiation exposure, benefiting patients and operators. Physicians should compare baseline radiation levels with the literature and adopt dose-reduction techniques. LungVision's lower dose indices render it effective for real-time 3D imaging during navigational bronchoscopy while reducing radiation dose.

Facet joint distance measurement using digital tomosynthesis while standing

The zygapophyseal (facet) joint plays a critical role in load transmission and stability of the spine, and facet degeneration is a common consequence of aging and osteoarthritis. The ability to accurately measure facet space is important, as decreased facet space is associated with facet degeneration and lower back pain. Although grading systems exist for assessing facet joint space narrowing, static imaging fails to characterize changes in the facet gap under load that play a role in segmental stability. Current methods for estimating the dynamic behavior of the facet joint are either inaccurate, radiation costly, or clinically impractical. In the current study, we demonstrate the feasibility of a novel method for 3D measurement of facet joint space using digital tomosynthesis (DTS) imaging in supine and standing positions. Facet gap measurements were found to be strongly correlated with (r to 0.98) and accurate (<20 µm error for median facet gap) relative to microcomputed tomography reference values. In a pilot in vivo demonstration with seven participants, the effect of physiological loading was detectable, with median facet joint space being larger in standing as compared to supine images (p < 0.0001). The presented approach may be useful in directly characterizing changes in the facet joint relevant to segmental stability that are not readily assessed via current clinical imaging methods.

Is It Safe to Omit Any Chest X-Ray Before Removing the Chest Drain After Elective, Non-Cardiac Thoracic Surgery? A Single-Center, Retrospective, Case-Control Study

BACKGROUND

Every patient undergoing non-cardiac thoracic surgery will receive several chest X-rays through the perioperative period. The patient might receive a preoperative X-ray as a baseline as well as several X-rays before and after drain removal. This routine has several disadvantages, for the patient, the health care system and the medical staff. Purpose of this study was to examine if all X-rays before removal of the drain can be omitted.

METHODS

Two hundred fifty-five patients who underwent elective thoracic surgery were included in this retrospective analysis. Patients undergoing urgent procedures or empyema surgery, as well as patients with symptoms requiring further diagnostic measures or patients who required clamping of the drain before removal, were excluded.

RESULTS

Forty-five patients received an X-ray before removal of the drain, and 210 patients did not. The X-ray group developed significantly more minor complications than the no X-ray group. 46.7% of the X-rays before drain removal (X-ray group) were reported with abnormalities. However, these abnormalities never led to a change in patient care. Drainage time and postoperative hospital stay were significantly longer in the X-ray group.

CONCLUSIONS

Omitting any X-ray between surgery and removal of the chest drain appears to be safe in our retrospective patient cohort. The proposed benefits of omitting the X-ray are very relevant for the health care system, the medical and nursing teams, and, more importantly, for the patients. Evidence suggests that X-ray of patients regularly do not exist. It is therefore reasonable to consider exploring this question in a formal prospective trial.

Ultra-Low Dose Computed Tomography Imaging in Quantifying Bone Trauma and Disorders: A Cross-Sectional Study

Background

X-ray computed tomography (CT) is a standard tool for diagnosing bone abnormalities. CT dose optimization is strongly recommended, due to the stochastic effects of x-ray. This study aims to assess the effectiveness of ultra-low-dose CT (ULD-CT) imaging, reconstructed using an Iterative Reconstruction (IR) algorithm, in detecting bone trauma and disorders.

Methods

In the present cross-sectional study, 71 patients with CT requests for spine or extremity (limb) bone underwent scanning using standard dose (SD) and ULD-CT protocols, in Shahid Faghihi Hospital, Shiraz, Iran from June 2019 to June 2020. The SD and ULD-CT protocols used 120 kVp and 80 kVp, respectively. The CT images were reconstructed using the standard and IR algorithms. CT dose indices, including the volume CT dose index (CTDIvol), dose-length product (DLP), and effective dose (ED), were employed. To assess image quality, a five-point scoring system was used. The sensitivity and specificity of the ULD-CT images were calculated.

Results

The findings indicated that ULD-CT images accurately identified 113 out of 118 bone trauma and disorders. The quality of ULD-CT images received "very good", "good" and "acceptable" scores for both spine and extremity (limb) bones. The sensitivity and specificity of ULD-CT images for bone trauma and disorders were 67%-95% and 100%, respectively, with about a 98% dose reduction.

Conclusion

The ULD-CT protocol for bone imaging achieved a remarkable dose reduction, while the image quality was reported as acceptable. Consequently, ULD-CT images reconstructed using an IR are suitable and can be tuned further in the future for acceptable use in patients with bone trauma and disorders.

Dosimetry Testing for a New In Vivo X-ray Fluorescence Measurement System

ABSTRACT

Lead exposure poses severe health risks to individuals, impacting cognitive function, growth, learning, and behavior. Current lead detection methods, primarily blood testing and x-ray fluorescence (XRF) of bone, have limitations. This study introduces a novel in vivo XRF measurement system using K-shell energies of lead, addressing limitations of previous methods. The study aimed to characterize beam directionality, subject radiation dose, and operator occupational exposure. Using a high-energy x-ray tube and room-temperature detectors, various parameters were assessed with bone and tissue phantoms. Dose measurements were taken by altering voltage, current, and shielding. Scatter and spatial measurements highlighted increased scatter with bone and tissue presence, emphasizing the safest positions for bystanders and operators. Results exhibited expected dose rate changes with varying parameters, showcasing the impact of bone and tissue on scatter radiation. The system's total body effective dose (with an 8-mm molybdenum shielding indicating minimal risk compared to established public dose limits) for an adult was 1.94 μSv; for a child aged 10 y, it was 3.28 μSv. This system demonstrates promising capabilities for lead exposure monitoring, offering negligible occupational exposure and minimal risk to individuals being scanned. Its safety and efficacy position it as a valuable tool in assessing lead exposure, potentially improving preventive measures.

A study for revising diagnostic reference levels for intra-oral radiology in Cyprus

BACKGROUND

Intra-oral radiography (IOR) is an imaging technique that uses X-rays to diagnose dental conditions. Establishing Diagnostic Reference Levels (DRLs) is crucial to optimising radiation doses and enhancing patient safety.

OBJECTIVE

This study was undertaken to propose national DRLs for IOR in Cyprus for both children and adults. The study also sought to compare dose values across different detector types, a task of significant importance in dental radiography.

METHODS

Data was collected from 115 intraoral units in 87 private centres in Cyprus, using incident air kerma (Ki) as the parameter. Statistical analysis was conducted based on Adulthood and detector types, such as direct digital detector (DDD), indirect digital detector (IDD) and film.

RESULTS

The study revealed variability in dosing values, with third-quartile doses higher for adults than paediatric patients. DDD exhibited the lowest dose values, while film had the highest. Proposed DRLs were notably lower than the current valid DRL in Cyprus, emphasising the need for re-establishment.

CONCLUSION

The values obtained can aid the national authority in establishing national DRLs in IOR. Establishing national intraoral DRLs in Cyprus is a crucial step towards ensuring the safety and fairness of dental care in the country. With the implementation of this initiative, patients can be assured that they are receiving the highest quality of care possible.

Neutron Activation Dose Assessment Based on a Human Head Phantom Post-BNCT

ABSTRACT

This study aims to assess the residual radioactivity produced in the human head phantom following irradiation from a boron neutron capture therapy neutron source based on a 2.8 MeV proton accelerator. Using Monte Carlo software to simulate irradiation on a head phantom based on ICRP Publication 110, it was found that, in addition to the nuclides 24Na, 38Cl, and 42K reported in other literature, 32P is the nuclide that contributes the most to the internal exposure dose in patients post-BNCT. Calculations indicate that the effective dose resulting from 60 min of irradiation activation ranges between 148 and 401 μSv, which is relatively low. This study also analyzed the dose rate at a distance of 60 cm from the activated head. Approximately 5 min after irradiation ends, short-lived nuclides such as 19O and 20F decay completely, reducing the dose rate to below 1 μSv h-1. Although nuclides like 24Na will continue to emit radiation, the dose rate remains at a safe level.

DXA images vs. pelvic radiographs: Reliability of hip morphology measurements

OBJECTIVE

Dual-energy x-ray absorptiometry (DXA) images are increasingly used to study hip morphology. Whether hip morphology measurements are consistent between DXA images and radiographs is unknown. Therefore, we investigated the agreement and reliability of the measurements performed on DXA images and radiographs.

DESIGN

We included participants from the Rotterdam study, a population-based cohort study, who received a hip DXA image and pelvic radiograph on the same day. The acetabular depth-width ratio (ADR), modified acetabular index (mAI), alpha angle (AA), Wiberg and lateral center edge angle (WCEA, LCEA), extrusion index (EI) and triangular index ratio (TIR) were automatically determined on both imaging modalities. The intraobserver and intermethod agreement were studied using Bland-Altman methods, and the reliability was assessed using intraclass correlation coefficients (ICC). Secondly, the diagnostic agreement regarding dysplasia, cam, and pincer morphology was assessed using percent agreement and Cohen's kappa.

RESULTS

A total of 750 hips from 411 individuals, median age 67.3 years (range 52.2 - 90.6), 45.5% male, were included. The following intermethod ICCs (95% CI) were obtained: ADR 0.85 (0.74-0.91), mAI 0.75 (0.52-0.85), AA 0.72 (0.68-0.75), WCEA 0.81 (0.74-0.85), LCEA 0.93 (0.91-0.94), EI 0.88 (0.84-0.91), and TIR 0.81 (0.79-0.84). We found comparable intraobserver ICCs for each morphological measurement.

CONCLUSION

DXA images and pelvic radiographs could both reliably be used to study hip morphology. Due to the lower radiation burden, DXA images could be an excellent alternative to pelvic radiographs for research purposes.

The Role of Interventional Radiology in Managing Placenta Accreta Spectrum Disorder

Interventional Radiology (IR) can be a crucial player in managing placenta accrete spectrum disorder (PAS), offering minimally invasive angiographic techniques that can prevent or control hemorrhage and preserve fertility. These include prophylactic balloon occlusion of the aorta or iliac arteries, preoperative catheter placement in the iliac or uterine arteries for subsequent embolization, or pre-emptive arterial embolization preceding hysterotomy and delivery. This review provides obstetricians with an overview of IR's role in the management of PAS by describing specific endovascular techniques; existing outcomes data; and considerations for protocol development, preoperative planning, and intraoperative dynamics for when IR assists with PAS cases.

Assessing radiation doses and proposing DRLs for nuclear medicine procedures for pediatric and adult patients in Madinah, Saudi Arabia

BACKGROUND

Nuclear medicine diagnostic and treatment procedures represent significant sources of ionizing radiation exposure for both staff and patients. Consequently, assessing and optimizing radiation doses are crucial to minimize potential side effects.

AIM

This study seeks to evaluate the effective radiation doses associated with common diagnostic and treatment procedures, as well as propose diagnostic reference levels (DRLs), within two nuclear medicine centers in Madinah, Saudi Arabia.

METHODOLOGY

Data from 445 patients were gathered from two nuclear medicine centers in the Madinah region of Saudi Arabia. The data were categorized based on the type of nuclear medicine (NM) procedure, the chemical composition of the administered radiopharmaceutical, as well as patient age and weight. Effective radiation doses for prevalent NM procedures were computed, and suggested DRLs were formulated.

RESULTS

Effective radiation doses were analyzed for 16 adult and 2 pediatric NM procedures (divided into 8 groups). The effective radiation doses for adult diagnostic nuclear medicine procedures range from 0.05 mSv (Nanocoloid) to 29 mSv (67Ga-citrate). For pediatric procedures, the doses range from 0.80 mSv (5-year-old undergoing renal DTPA) to 1.6 mSv (1-year-old undergoing renal DMSA). Furthermore, DRL values were determined for both adult and pediatric NM procedures. The study's findings demonstrated a high degree of concordance between effective radiation doses and DRL values, aligning well with previously published research.

CONCLUSION

While the effective radiation doses outlined in this study were generally within acceptable limits and consistent with prior research findings, optimizing radiation doses remains imperative, particularly for pediatric NM procedures.

Simulated low-dose dark-field radiography for detection of COVID-19 pneumonia

BACKGROUND

Dark-field radiography has been proven to be a promising tool for the assessment of various lung diseases.

PURPOSE

To evaluate the potential of dose reduction in dark-field chest radiography for the detection of the Coronavirus SARS-CoV-2 (COVID-19) pneumonia.

MATERIALS AND METHODS

Patients aged at least 18 years with a medically indicated chest computed tomography scan (CT scan) were screened for participation in a prospective study between October 2018 and December 2020. Patients were included if they had a CO-RADS (COVID-19 Reporting and Data System) score ≥ 4 (COVID-19 group) or if they had no pathologic lung changes (controls). A total of 89 participants with a median age of 60 years (interquartile range 48 to 68 yrs.) were included in this study. Dark-field and attenuation-based radiographs were simultaneously obtained by using a prototype system for dark-field radiography. By modifying the image reconstruction algorithm, low-dose radiographs were simulated based on real participant images. The simulated radiographs corresponded to 50%, 25%, and 13% of the full dose (41.9 μSv, median value). Four experienced radiologists served as blinded readers assessing both image modalities, displayed side by side in random order. The presence of COVID-19-associated lung changes was rated on a scale from 1 to 6. The readers' diagnostic performance was evaluated by analyzing the area under the receiver operating characteristic curves (AUC) using Obuchowski's method. Also, the dark-field images were analyzed quantitatively by comparing the dark-field coefficients within and between the COVID-19 and the control group.

RESULTS

The readers' diagnostic performance in the image evaluation, as described by the AUC value (where a value of 1 corresponds to perfect diagnostic accuracy), did not differ significantly between the full dose images (AUC = 0.86) and the simulated images at 50% (AUC = 0.86) and 25% of the full dose(AUC = 0.84) (p>0.050), but was slightly lower at 13% dose (AUC = 0.82) (p = 0.038). For all four radiation dose levels, the median dark-field coefficients within groups were identical but different significantly by 15% between the controls and the COVID-19 pneumonia group (p<0.001).

CONCLUSION

Dark-field imaging can be used to diagnose the Coronavirus SARS-CoV-2 (COVID-19) pneumonia with a median dose of 10.5 μSv, which corresponds to 25% of the original dose used for dark-field chest imaging.

Is Frequent Imaging Necessary? Impact of Computed Tomography During Follow-up After Surgical Treatment for Nonmetastatic Renal Cell Carcinoma: A Systematic Review

BACKGROUND AND OBJECTIVE

Current guidelines on radiological follow-up (FU) for patients after treatment for nonmetastatic renal cell carcinoma (RCC) are not based on robust evidence. This review aims to evaluate whether the 2022 European Association of Urology (EAU) guidelines are noninferior, in terms of recurrence and (overall) survival, to a higher imaging frequency of computed tomography (CT) of the chest and abdomen.

METHODS

A literature search of relevant search machines (PubMed/Medline and EMBASE) was performed up to May 29, 2024. Studies describing patients with nonmetastatic RCC who underwent curative treatment by means of partial or radical nephrectomy were included. Studies with a higher number of CT scans than recommended by the EAU were compared with those that followed guidelines by examining recurrences and survival data. Outcomes were classified into risk groups according to the 2022 EAU guidelines.

KEY FINDINGS AND LIMITATIONS

Twenty studies met our inclusion criteria. Sixteen (80%) studies employed a higher imaging frequency during FU compared with 2022 EAU guideline recommendations, two studies (10%) followed the guidelines, and two studies (10%) performed less imaging. Recurrences were rare in low-risk studies (0-7.6%) and varied among high-risk studies, ranging between 33% and 40% in randomized controlled trials and 11% and 28% in retrospective studies. A meta-analysis was not suited due to clinical diversity, and the risk of bias was high among cohort studies.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Most studies employ a higher imaging frequency during FU after treatment for nonmetastatic RCC than recommended by the 2022 EAU guidelines. Survival and recurrence rates suggest that more frequent imaging than recommended by the EAU may not be advantageous, although high-quality evidence is needed to further improve guidelines.

PATIENT SUMMARY

In this review, we assessed radiological follow-up schedules for patients after surgery for kidney cancer and compared these with the follow-up schedules recommended by the European Association of Urology guidelines. We found that most studies apply more frequent imaging during follow-up than recommended by guidelines, although survival and recurrence rates are similar among studies with different imaging frequencies. We conclude that more frequent imaging than recommended by guidelines may not be necessary and that prospective studies are needed to determine whether imaging can be reduced further during follow-up.

HELMET: A Hybrid Machine Learning Framework for Real-Time Prediction of Edema Trajectory in Large Middle Cerebral Artery Stroke

Malignant cerebral edema occurs when brain swelling displaces and compresses vital midline structures within the first week of a large middle cerebral artery stroke. Early interventions such as hyperosmolar therapy or surgical decompression may reverse secondary injury but must be administered judiciously. To optimize treatment and reduce secondary damage, clinicians need strategies to frequently and quantitatively assess the trajectory of edema using updated, relevant information. However, existing risk assessment tools are limited by the absence of structured records capturing the evolution of edema and typically estimate risk at a single time point early in the admission, therefore failing to account for changes in variables over the following hours or days. To address this, we developed and validated dynamic machine learning models capable of accurately predicting the severity of midline structure displacement, an established indicator of malignant edema, in real-time. Our models can provide updated estimations as frequently as every hour, using data from structured time-varying patient records, radiographic text, and human-curated neurological characteristics. Our work resulted in two novel multi-class classification models, collectively named Hybrid Ensemble Learning Models for Edema Trajectory (HELMET), predicting the progression of midline shift over 8-hour (HELMET-8) and 24-hour windows (HELMET-24), respectively. HELMET combines transformer-based large language models with supervised ensemble learning, demonstrating the value of merging human expertise and multimodal health records in developing clinical risk scores. Both models were trained on a retrospective cohort of 15,696 observations from 623 patients hospitalized with large middle cerebral artery ischemic stroke and were externally validated using 3,713 observations from 60 patients at a separate hospital system. Our HELMET models are accurate and generalize effectively to diverse populations, achieving a cross-validated mean area under the receiver operating characteristic score of 96.6% in the derivation cohort and 92.5% in the external validation cohort. Moreover, our approach provides a framework for developing hybrid risk prediction models that integrate both human-extracted and algorithm-derived multi-modal inputs. Our work enables accurate estimation of complex, dynamic, and highly specific clinical targets, such as midline shift, in real-time, even when relevant structured information is limited in electronic health record databases.

Unnecessary diagnostic imaging requested by medical students during a first day of residency simulation: an explorative study

BACKGROUND

Physicians' choice of appropriate tests in the diagnostic process is crucial for patient safety. The increased use of medical imaging has raised concerns about its potential overuse. How appropriately medical students order diagnostic tests is unknown. We explored their ordering behavior of diagnostic imaging during a simulated first day of residency.

METHODS

In total, 492 undergraduate medical students participated in the simulation. After history taking with simulated patients, the students used an electronic system for requesting diagnostic tests. The analysis focused on 16 patient cases, each managed by at least 50 students. We calculated the total number of ordered images and unnecessary radiation exposure in millisievert per patient and performed one sample t-tests (one tailed) with an expected mean of zero on a Bonferroni-corrected alpha level of 0.003 for the independent variable of unnecessary radiation exposure.

RESULTS

Unnecessary diagnostic imaging was ordered across all patient cases. Ultrasound, especially abdominal ultrasound, X-rays of the thorax, and abdominal CTs were notably overused in 90.9%, 80.0%, and 69.2% of all patient cases, respectively. Unnecessary requests of imaging related to radiation resulted in radiation over-exposure for nearly all patients, with 37.5% of all patients being exposed to a significant radiation overdose on average.

CONCLUSION

Medical students' overuse of diagnostic imaging can be explained by patient-related factors like anxiety and medical factors like missing clinical information leading to cognitive biases in patient workup. This suggests the need for interventions to improve students' clinical decision-making and reduce cognitive biases. Investigating student-specific factors being associated with overuse of diagnostic imaging would be of additional interest.

AT, Raavi V, Easwaramoorthy V, Murugaiyan P, Perumal V. Enhanced γ-H2AX Foci Frequency and Altered Gene Expression in Participants Exposed to Ionizing Radiation During I-131 Nuclear Medicine Procedures

Purpose

Ionizing radiation-based technologies are extensively used in the diagnosis and treatment of diseases. While utilizing the technologies, exposure to a certain amount of radiation is unavoidable. Data can be obtained from participants who received radiation during medical imaging and therapeutic purposes to predict the effects of low-dose radiation.

Methods

To understand the effects of low-dose radiation, participants (n = 22) who received radioactive I-131 for scan/therapy were used as a model in this study. Blood samples were drawn pre- and post-administration of I-131. Biological effects were measured using markers of DNA damage (γ-H2AX, micronucleus (MN), and chromosomal aberrations (CA)) and response to damage through gene expression changes (ATM, CDKN1A, DDB2, FDXR, and PCNA) in blood samples.

Results

Mean frequency of γ-H2AX foci in pre-samples was 0.28 ± 0.16, and post-samples were 1.03 ± 0.60. γ-H2AX foci frequency obtained from post-samples showed significant (p < 0.0001) and a heterogeneous increase in all the participants (received I-131 for scan/therapy) when compared to pre-samples. A significant increase (p < 0.0001) in MN and CA frequency was also observed in participants who received the I-131 therapy. Gene expression analysis indicates that all genes (ATM, CDKN1A, DDB2, FDXR, and PCNA) were altered in post-samples, although with varying degrees, suggesting that the cellular responses to DNA damage, such as damage repair, cell cycle regulation to aid in repair and apoptosis are increased, which priority is given to repair, followed by apoptosis.

Conclusion

The results of this study indicate that the participants who received I-131 (low doses of β- and γ-radiation) can produce substantial biological effects.

Automatic localization of anatomical landmarks in head cine fluoroscopy images via deep learning

BACKGROUND

Fluoroscopy guided interventions (FGIs) pose a risk of prolonged radiation exposure; personalized patient dosimetry is necessary to improve patient safety during these procedures. However, current FGIs systems do not capture the precise exposure regions of the patient, making it challenging to perform patient-procedure-specific dosimetry. Thus, there is a pressing need to develop approaches to extract and use this information to enable personalized radiation dosimetry for interventional procedures.

PURPOSE

To propose a deep learning (DL) approach for the automatic localization of 3D anatomical landmarks on randomly collimated and magnified 2D head fluoroscopy images.

MATERIALS AND METHODS

The model was developed with datasets comprising 800 000 pseudo 2D synthetic images (mixture of vessel-enhanced and non-enhancement), each with 55 annotated anatomical landmarks (two are landmarks for eye lenses), generated from 135 retrospectively collected head computed tomography (CT) volumetric data. Before training, dynamic random cropping was performed to mimic the varied field-size collimation in FGI procedures. Gaussian-distributed additive noise was applied to each individual image to enhance the robustness of the DL model in handling image degradation that may occur during clinical image acquisition in a clinical environment. The model was trained with 629 370 synthetic images for approximately 275 000 iterations and evaluated against a synthetic image test set and a clinical fluoroscopy test set.

RESULTS

The model shows good performance in estimating in- and out-of-image landmark positions and shows feasibility to instantiate the skull shape. The model successfully detected 96.4% and 92.5% 2D and 3D landmarks, respectively, within a 10 mm error on synthetic test images. It demonstrated an average of 3.6 ± 2.3 mm mean radial error and successfully detected 96.8% 2D landmarks within 10 mm error on clinical fluoroscopy images.

CONCLUSION

Our deep-learning model successfully localizes anatomical landmarks and estimates the gross shape of skull structures from collimated 2D projection views. This method may help identify the exposure region required for patient-specific organ dosimetry in FGIs procedures.

Pulmonary nodule visualization and evaluation of AI-based detection at various ultra-low-dose levels using photon-counting detector CT

BACKGROUND

Radiation dose should be as low as reasonably achievable. With the invention of photon-counting detector computed tomography (PCD-CT), the radiation dose may be considerably reduced.

PURPOSE

To evaluate the potential of PCD-CT for dose reduction in pulmonary nodule visualization for human readers as well as for computer-aided detection (CAD) studies.

MATERIAL AND METHODS

A chest phantom containing pulmonary nodules of different sizes/densities (range 3-12 mm and -800-100 HU) was scanned on a PCD-CT with standard low-dose protocol as well as with half, quarter, and 1/40 dose (CTDIvol 0.4-0.03 mGy). Dose-matched scans were performed on a third-generation energy-integrating detector CT (EID-CT). Evaluation of nodule visualization and detectability was performed by two blinded radiologists. Subjective image quality was rated on a 5-point Likert scale. Artificial intelligence (AI)-based nodule detection was performed using commercially available software.

RESULTS

Highest image noise was found at the lowest dose setting of 1/40 radiation dose (eff. dose = 0.01mSv) with 166.1 ± 18.5 HU for PCD-CT and 351.8 ± 53.0 HU for EID-CT. Overall sensitivity was 100% versus 93% at standard low-dose protocol (eff. dose = 0.2 mSv) for PCD-CT and EID-CT, respectively. At the half radiation dose, sensitivity remained 100% for human reader and CAD studies in PCD-CT. At the quarter radiation dose, PCD-CT achieved the same results as EID-CT at the standard radiation dose setting (93%, P = 1.00) in human reading studies. The AI-CAD system delivered a sensitivity of 93% at the lowest radiation dose level in PCD-CT.

CONCLUSION

At half dose, PCD CT showed pulmonary nodules similar to full-dose PCD, and at quarter dose, PCD CT performed comparably to standard low-dose EID CT. The CAD algorithm is effective even at ultra-low doses.

Is Immediate Postoperative Radiograph Necessary Following Robotic-Assisted Total Knee Arthroplasty?

The necessity of immediate postoperative radiographs following total knee arthroplasty (TKA) has long been debated. With the increasing use of robotic-assisted TKA (RTKA), and thus more precise implant placement, the need for immediate postoperative radiographs to determine implant positioning may be unnecessary. We sought to evaluate implant position on the immediate postoperative radiographs following RTKA to determine their necessity. A retrospective review of 150 RTKAs was performed. The posterior slopes for all TKAs were recorded based on the preoperative three-dimensional template. Additionally, two independent trained researchers (J.G./L.B.) each measured the posterior slope of the postoperative day 0 (POD0) radiograph and postoperative week 2 radiograph. The difference in posterior slope measurement between template and POD0, between template and postoperative week 2, and between POD0 and postoperative week 2 was calculated. Of the 150 TKAs performed, there were no periprosthetic fractures found on the POD0 radiograph. The mean difference between the templated posterior slope and measured posterior slope on POD0 was 0.04 degrees (standard deviation [SD], 1.01; p = 0.615). There was a weak correlation between the two values (rs [95% confidence interval (CI)], 0.38 [0.21, 0.53]). When comparing the template to the postoperative week 2 radiographs, there was a mean difference of 0.02 degrees (SD, 0.48; p = 0.556).  However, a moderate to strong correlation was noted (rs [95% CI], 0.71 [0.61, 0.79]). Comparison of the mean posterior slope from POD0 radiograph to that of postoperative week 2 radiograph showed a mean difference of 0.06 degrees (SD, 1.0; p = 0.427). A weak correlation was found between these two values (rs [95% CI], 0.43 [0.26, 0.56]). Given the accuracy and precision of RTKA, along with the ability to decrease cost and radiation, immediate postoperative radiograph may be unnecessary, when pertaining to the uncomplicated RTKA. However, if there is concern for intraoperative fracture, long stems placed in a revision arthroplasty, or other intraoperative complications, then postoperative radiographs are encouraged.

Radiation Detectors and Sensors in Medical Imaging

Medical imaging instrumentation design and construction is based on radiation sources and radiation detectors/sensors. This review focuses on the detectors and sensors of medical imaging systems. These systems are subdivided into various categories depending on their structure, the type of radiation they capture, how the radiation is measured, how the images are formed, and the medical goals they serve. Related to medical goals, detectors fall into two major areas: (i) anatomical imaging, which mainly concerns the techniques of diagnostic radiology, and (ii) functional-molecular imaging, which mainly concerns nuclear medicine. An important parameter in the evaluation of the detectors is the combination of the quality of the diagnostic result they offer and the burden of the patient with radiation dose. The latter has to be minimized; thus, the input signal (radiation photon flux) must be kept at low levels. For this reason, the detective quantum efficiency (DQE), expressing signal-to-noise ratio transfer through an imaging system, is of primary importance. In diagnostic radiology, image quality is better than in nuclear medicine; however, in most cases, the dose is higher. On the other hand, nuclear medicine focuses on the detection of functional findings and not on the accurate spatial determination of anatomical data. Detectors are integrated into projection or tomographic imaging systems and are based on the use of scintillators with optical sensors, photoconductors, or semiconductors. Analysis and modeling of such systems can be performed employing theoretical models developed in the framework of cascaded linear systems analysis (LCSA), as well as within the signal detection theory (SDT) and information theory.

10 Years of Antenatal Hydronephrosis Experience: Comparing Two Different Guidelines

BACKGROUND

Antenatal hydronephrosis refers to the dilation of the renal pelvis and/or calyces in the developing fetus. The challenge lies in distinguishing between cases that warrant long-term follow-up or surgical intervention and those with transient hydronephrosis that require minimal invasive investigations.

MATERIALS AND METHODS

Our study aimed to assess and contrast the efficacy of the 2015 Congenital Anomalies of Kidney and Urinary Tract Guideline from the Turkish Society of Pediatric Nephrology with the Tepecik Antenatal Hydronephrosis Guideline, which was previously employed in our hospital. We conducted a comparative analysis of demographic data, outcome conditions, additional imaging requirements and quantities, radiation exposures, and rates of surgical interventions between two groups.

RESULTS

Group 2 had a significantly higher detection rate of Vesicoureteral Reflux via voiding cystourethrogram at 38.5% compared to Group 1's 13.4% (p<0.01). The incidence of abnormal findings with dimercaptosuccinic acid was similar between Group 1 (28.5%) and Group 2 (26.4%) (p>0.01), but Group 2 had a higher rate of obstruction diagnosis at 68.8% versus Group 1's 29.4% (p<0.01). Group 1 had greater median radiation exposure (500 mrem vs. 200 mrem, p<0.01), and a higher proportion of patients underwent surgery (34.2% vs. 21.9%, p<0.01).

CONCLUSION

This study showed that the new guideline required fewer tests, was less invasive, and exposed patients to less radiation than the old guideline.

Role of scheduled repeat CT scan in traumatic brain injuries: A prospective observational study

Background

Scheduled CT scan is a routine practice at many centers after traumatic brain injury (TBI), but it has been questioned by few authors. The majority of the studies are reported in mild TBI; however, no specific data exist for the same in moderate and severe TBI.

Methods

This was a single-center and 1-year prospective study. All cases with TBI who underwent scheduled repeat scans were included in the study. Patients who underwent emergency surgery after first computed tomography (CT) and those who expired before repeat CT were excluded from the study. Data included demographics, Glasgow coma scale (GCS) score, initial head CT findings, findings of repeat CT, and the need for any intervention (medical/surgical).

Results

A total of 231 cases were analyzed. The mean time interval for the repeat CT was 7.8 h. One hundred and seventy-one patients underwent scheduled repeat CT (Group 1), 53 patients with GCS >13 were discharged from emergency before the repeat scan (Group 2), and seven cases underwent repeat CT before the scheduled time in view of clinical deterioration (Group 3). The mean age and gender did not vary significantly between the three groups. Mixed lesions predominated in all; however, the proportion significantly differed between groups. In Group 1, two patients required surgery; in Group 3, all patients required a significant change in treatment, whereas none deteriorated or required a repeat scan in Group 2.

Conclusion

In our study, the yield of routine repeat CT scans requiring surgery was 3.5%. Based on the results of our study and the observations from previous studies, we have proposed a few general working statements regarding indications for repeat CT scans in TBI.

Utility of White Light Scanning as an Alternative to Computed Tomography to Evaluate Severity of Pectus Excavatum Deformity

BACKGROUND

Pectus excavatum (PE) severity and surgical candidacy are determined by computed tomography (CT)-delineated Haller Index (HI) and Correction Index (CI). White light scanning (WLS) has been proposed as a non-ionizing alternative. The purpose of this retrospective study is to create models to determine PE severity using WLS as a non-ionizing alternative to CT.

METHODS

Between November 2015 and February 2023, CT and WLS were performed for children ≤18 years undergoing evaluation at a high-volume, chest-wall deformity clinic. Separate quadratic discriminate analysis models were developed to predict CT HI ≥ 3.25 and CT CI ≥ 28% indicating surgical candidacy. Two bootstrap forest models were trained on WLS measurements and patient demographics to predict CT HI and CT CI values then compared to actual index values by intraclass correlation coefficient (ICC).

RESULTS

In total, 242 patients were enrolled (86.4% male, mean [SD] age 15.2 [1.3] years). Quadratic discriminate analysis models predicted CT HI ≥ 3.25 with specificity = 91.7%, PPV = 97.7% (AUC = 0.91), and CT CI ≥ 28% with specificity = 92.3%, PPV = 93.5% (AUC = 0.84). Bootstrap forest model predicted CT HI with training dataset ICC (95% CI) = 0.91 (0.88-0.93, R2 = 0.85) and test dataset ICC (95% CI) = 0.86 (0.71-0.94, R2 = 0.77). For CT CI, training dataset ICC (95% CI) = 0.91 (0.81-0.93, R2 = 0.86) and test dataset ICC (95% CI) = 0.75 (0.50-0.88, R2 = 0.63).

CONCLUSIONS

Using noninvasive and nonionizing WLS imaging, we can predict PE severity at surgical threshold with high specificity obviating the need for CT. Furthermore, we can predict actual CT HI and CI with moderate-excellent reliability. We anticipate this point-of-care tool to obviate the need for most cross-sectional imaging during surgical evaluation of PE.

LEVEL OF EVIDENCE

Level III.

STUDY TYPE

Study of Diagnostic Test.

CT in musculoskeletal imaging: still helpful and for what?

Computed tomography (CT) is a common modality employed for musculoskeletal imaging. Conventional CT techniques are useful for the assessment of trauma in detection, characterization and surgical planning of complex fractures. CT arthrography can depict internal derangement lesions and impact medical decision making of orthopedic providers. In oncology, CT can have a role in the characterization of bone tumors and may elucidate soft tissue mineralization patterns. Several advances in CT technology have led to a variety of acquisition techniques with distinct clinical applications. These include four-dimensional CT, which allows examination of joints during motion; cone-beam CT, which allows examination during physiological weight-bearing conditions; dual-energy CT, which allows material decomposition useful in musculoskeletal deposition disorders (e.g., gout) and bone marrow edema detection; and photon-counting CT, which provides increased spatial resolution, decreased radiation, and material decomposition compared to standard multi-detector CT systems due to its ability to directly translate X-ray photon energies into electrical signals. Advanced acquisition techniques provide higher spatial resolution scans capable of enhanced bony microarchitecture and bone mineral density assessment. Together, these CT acquisition techniques will continue to play a substantial role in the practices of orthopedics, rheumatology, metabolic bone, oncology, and interventional radiology.

Ultralow-Dose Dynamic Expiratory CT and Repeated Imaging Enhance Evaluation for Tracheomalacia

OBJECTIVE

This study aims to determine if a novel imaging protocol (ultralow-dose dynamic expiratory computed tomography [CT] with repeated imaging) identifies tracheomalacia (TM) more reliably than traditional dynamic tracheal CT.

METHODS

We performed a retrospective evaluation of 184 consecutive ultralow-dose dynamic CTs for TM during 2017. The protocol obtains images during 1 inspiration and 2 forced expirations. Tracheal narrowing during both expirations (airway narrowing [percentage] during first dynamic expiration CT [DE1], airway narrowing [percentage] during second dynamic expiration CT [DE2]) was reported as a percentage of inspiratory area. We identified maximum narrowing of each patient's sequence (maximum narrowing [percentage] on either dynamic expiration CT [DEmax] = greatest narrowing of DE1 or DE2) and compared DE1, DE2, and DEmax in individual studies and between patients. Outcomes included frequency of TM, tracheal narrowing, and severity. Reliability was assessed by comparing tracheal area narrowing and TM grade.

RESULTS

There was significantly more airway narrowing using 2 expiratory image acquisitions. Average DEmax tracheal area was 12% narrower than DE1 alone and 21% worse than DE2 alone (both P < 0.001). Using DEmax, TM was diagnosed 35% more often than DE1 alone and 31% more often than DE2 alone ( P < 0.001). DEmax identified more severe distribution of TM compared with DE1 or DE2 alone ( P < 0.001). Reliability between DE1 and DE2 was good for tracheal narrowing and moderate for TM grade. The mean effective radiation dose was 2.41 millisievert (mSv) for routine inspiration CT and 0.07 mSv for each dynamic expiration CT (total effective radiation, 2.55 mSv).

CONCLUSIONS

Dynamic expiration CT with 2 expiratory image acquisitions enhanced evaluation of TM, minimally increased radiation dose, and should be considered as a noninvasive screening option.

Evolving Radiological Approaches in the Diagnosis and Monitoring of Arachnoiditis Ossificans

Arachnoiditis ossificans (AO) is a rare and complex neurological condition characterized by pathological calcification or ossification of the arachnoid membrane. Arachnoiditis ranks as the third most frequent cause of failed back surgery syndrome (FBSS). This narrative review explores the evolving radiological approaches in its diagnosis and monitoring. The historical perspective traces the progression from plain radiographs to advanced imaging techniques. Current radiological modalities, including X-ray, computed tomography (CT), and magnetic resonance imaging (MRI), are discussed, highlighting their respective roles, advantages, and limitations. Emerging and advanced imaging modalities, such as high-resolution CT, 3T and 7T MRI, and PET/CT or PET/MRI, are examined for their potential to enhance diagnostic accuracy and monitoring capabilities. A comparative analysis of these imaging modalities considers their sensitivity, specificity, cost-effectiveness, and radiation exposure implications. The review also explores the crucial role of imaging in disease monitoring and treatment planning, including follow-up protocols, evaluation of disease progression, and guidance for interventional procedures. Future directions in the field are discussed, focusing on promising research areas, the potential of artificial intelligence and machine learning in image analysis, and identified gaps in current knowledge. The review emphasizes the importance of a multimodal imaging approach and the need for standardized protocols. It concludes that while significant advancements have been made, further research is necessary to fully understand the correlation between imaging findings and clinical outcomes. The continued evolution of radiological approaches is expected to significantly improve patient care and outcomes in AO.

WFUMB Review Paper. Incidental Findings in Otherwise Healthy Subjects, How to Manage: Liver

An incidental focal liver lesion (IFLL) is defined as a hepatic lesion identified in a patient imaged for an unrelated reason. They are frequently encountered in daily practice, sometimes leading to unnecessary, invasive and potentially harmful follow-up investigations. The clinical presentation and the imaging aspects play an important role in deciding if, and what further evaluation, is needed. In low-risk patients (i.e., without a history of malignant or chronic liver disease or related symptoms), especially in those younger than 40 years old, more than 95% of IFLLs are likely benign. Shear Wave liver Elastography (SWE) of the surrounding liver parenchyma should be considered to exclude liver cirrhosis and for further risk stratification. If an IFLL in a low-risk patient has a typical appearance on B-mode ultrasound of a benign lesion (e.g., simple cyst, calcification, focal fatty change, typical hemangioma), no further imaging is needed. Contrast-Enhanced Ultrasound (CEUS) should be considered as the first-line contrast imaging modality to differentiate benign from malignant IFLLs, since it has a similar accuracy to contrast-enhanced (CE)-MRI. On CEUS, hypoenhancement of a lesion in the late vascular phase is characteristic for malignancy. CE-CT should be avoided for characterizing probable benign FLL and reserved for staging once a lesion is proven malignant. In high-risk patients (i.e., with chronic liver disease or an oncological history), each IFLL should initially be considered as potentially malignant, and every effort should be made to confirm or exclude malignancy. US-guided biopsy should be considered in those with unresectable malignant lesions, particularly if the diagnosis remains unclear, or when a specific tissue diagnosis is needed.

Radiation exposure in pediatric videourodynamics: An evaluation of safety in comparison to voiding cystourethrogram

INTRODUCTION

Children with spina bifida (SB) undergo a videourodynamic study (VUDS) or urodynamic study and voiding cystourethrogram (VCUG). A standardized protocol for imaging during a pediatric VUDS has not been established. Our aim is to quantify radiation exposure and establish a baseline for children with spina bifida (SB) undergoing VUDS in current practice at our institution.

METHODS

This is a retrospective study from 2013 to 2020 of consecutive pediatric SB patients undergoing VUDS by a single provider. Patients were categorized into three groups based on age; group 1 (0-2 YR), group 2 (2-10 YR), group 3 (>10 YR). Radiation data was reported as mean air kerma (AK), dose area product (DAP) and exposure time (seconds). Effective dose (ED) was calculated based on radiation quantity (Air Kerma, AK) and organ sensitivity. The lifetime attributable risk (LAR) was calculated based on AK and a risk coefficient. Data points calculated for patients undergoing VUDS were then compared to age matched institutional VCUG data in the same age groups.

RESULTS

398 patients undergoing VUDS met inclusion criteria and 262 independent patients underwent VCUG. ED increased with age in both VUDS and VCUG. All VCUG groups were found to have a higher ED than VUDS. The LAR for VUDS groups 1-3 was 0.001, 0.002, and 0.006, respectively. Reported in percentages, there is a 0.1%, 0.2%, and 0.6% chance, respectively, of age groups 1, 2 and 3 developing cancer as a result of the radiation exposure from a VUDS.

DISCUSSION

Our study found that ED was low across all age groups for VUDS, comparing favorably to the VCUG groups. VCUG was selected as a benchmark comparison for its diagnostic similarities and, at times, overlapping indications. Few studies have described ED with respect to VUDS or extrapolate the ED of VUDS into LAR in the pediatric population. We recognize that we have not determined the true ED of the gonads and bladder, rather we have overestimated, as the data is based on an international reference point proximal to the exposed individual. However, LAR was calculated for each age group and revealed that patients are at a negligible increased risk of developing malignancy secondary to exposure compared to the general population.

CONCLUSION

Our current practice for pediatric VUDS has exhibited consistently low radiation exposure amongst all age groups. Moving forward, we have the foundation and flexibility to create an imaging protocol for pediatric VUDS, while taking more calculated steps toward incorporating ALARA, as low as reasonably achievable, principles. A protocol adhering to the ALARA principle could provide consistency across institutions and aid in multi-institutional studies.

Chest CT at X-Ray Dose Using a Noise-Mitigating Weighted Projection: The Thoracic Tomogram. Diagnostic Performance for Pneumonia Detection in Hemato-Oncology Patients

PURPOSE

To compare the diagnostic performance of a thick-slab reconstruction obtained from an ultra-low-dose CT (termed thoracic tomogram) with standard-of-care low-dose CT (SOC-CT) for rapid interpretation and detection of pneumonia in hemato-oncology patients.

METHODS

Hemato-oncology patients with a working diagnosis of pneumonia underwent an SOC-CT followed by an ultra-low-dose CT, from which the thoracic tomogram (TT) was reconstructed. Three radiologists evaluated the TT and SOC-CT in the following categories: (I) infectious/inflammatory opacities, (II) small airways infectious/inflammatory changes, (III) atelectasis, (IV) pleural effusions, and (V) interstitial abnormalities. The TT interpretation time and radiation dose were recorded. Sensitivity, specificity, diagnostic accuracy, ROC, and AUC were calculated with the corresponding power analyses. The agreement between TT and SOC-CT was calculated by Correlation Coefficient for Repeated Measures (CCRM), and the Shrout-Fleiss intra-class correlations test was used to calculate interrater agreement.

RESULTS

Forty-seven patients (mean age 58.7 ± 14.9 years; 29 male) were prospectively enrolled. Sensitivity, specificity, accuracy, AUC, and Power for categories I/II/III/IV/V were: 94.9/99/97.9/0.971/100, 78/91.2/86.5/0.906/100, 88.6/100/97.2/0.941/100, 100/99.2/99.3/0.995/100, and 47.6/100/92.2/0.746/87.3. CCRM between TT and SOC-CT for the same categories were .97/.81/.92/.96/.62 with an interobserver agreement of .93/.88/.82/.96/.61. Mean interpretation time was 18.6 ± 5.4 seconds. The average effective radiation dose of TT was similar to a frontal and lateral chest X-ray (0.27 ± 0.08 vs 1.46 ± 0.64 mSv for SOC-CT; P < .01).

CONCLUSION

Thoracic tomograms provide comparable diagnostic information to SOC-CT for the detection of pneumonia in immunocompromised patients at one-fifth of the radiation dose with high interobserver agreement.

Deep Learning for Pneumonia Detection in Chest X-ray Images: A Comprehensive Survey

This paper addresses the significant problem of identifying the relevant background and contextual literature related to deep learning (DL) as an evolving technology in order to provide a comprehensive analysis of the application of DL to the specific problem of pneumonia detection via chest X-ray (CXR) imaging, which is the most common and cost-effective imaging technique available worldwide for pneumonia diagnosis. This paper in particular addresses the key period associated with COVID-19, 2020-2023, to explain, analyze, and systematically evaluate the limitations of approaches and determine their relative levels of effectiveness. The context in which DL is applied as both an aid to and an automated substitute for existing expert radiography professionals, who often have limited availability, is elaborated in detail. The rationale for the undertaken research is provided, along with a justification of the resources adopted and their relevance. This explanatory text and the subsequent analyses are intended to provide sufficient detail of the problem being addressed, existing solutions, and the limitations of these, ranging in detail from the specific to the more general. Indeed, our analysis and evaluation agree with the generally held view that the use of transformers, specifically, vision transformers (ViTs), is the most promising technique for obtaining further effective results in the area of pneumonia detection using CXR images. However, ViTs require extensive further research to address several limitations, specifically the following: biased CXR datasets, data and code availability, the ease with which a model can be explained, systematic methods of accurate model comparison, the notion of class imbalance in CXR datasets, and the possibility of adversarial attacks, the latter of which remains an area of fundamental research.

Spatial Resolution for X-ray Excited Luminescence Chemical Imaging (XELCI)

Measuring chemical concentrations at the surface of implanted medical devices is important for elucidating the local biochemical environment, especially during implant infection. Although chemical indicator dyes enable chemical measurements in vitro, they are usually ineffective when measuring through tissue because the background obscures the dye signal and scattering dramatically reduces the spatial resolution. X-ray excited luminescent chemical imaging (XELCI) is a recent imaging modality which overcomes these limitations using a focused X-ray beam to excite a small spot of red light on scintillator-coated medical implants with well-defined location (because X-rays are minimally scattered) and low background. A spectrochemical indicator film placed over the scintillator layer, e.g., a polymer film containing pH-indicator dyes, absorbs some of the luminescence according to the local chemical environment, and this absorption is then detected by measuring the light intensity/spectrum passing through the tissue. A focused X-ray beam is used to scan point-by-point with a spatial resolution mainly limited by the X-ray beam width with minimum increase from X-ray absorption and scattering in the tissue. X-ray resolution, implant surface specificity, and chemical sensitivity are the three key features of XELCI. Here, we study spatial resolution using optically absorptive targets. For imaging a series of lines, the 20-80% knife-edge resolution was ∼285 (±15) μm with no tissue and 475 ± 18 and 520 ± 34 μm, respectively, through 5 and 10 mm thick tissue. Thus, doubling the tissue depth did not appreciably change the spatial resolution recorded through the tissue. This shows the promise of XELCI for submillimeter chemical imaging through tissue.

[SOP Leading symptom: flank pain]

In addition to triggers such as ureteral stones or pyelonephritis, the common symptom of flank pain can be associated with a whole range of conditions. This SOP is intended to give doctors in the emergency department an overview of the possible causes. Based on medical history, clincal examination including sonography and laboratory diagnostics, important differential diagnoses are addressed and an imaging algorithm is presented.

Developing Deep LSTMs With Later Temporal Attention for Predicting COVID-19 Severity, Clinical Outcome, and Antibody Level by Screening Serological Indicators Over Time

OBJECTIVE

The clinical course of COVID-19, as well as the immunological reaction, is notable for its extreme variability. Identifying the main associated factors might help understand the disease progression and physiological status of COVID-19 patients. The dynamic changes of the antibody against Spike protein are crucial for understanding the immune response. This work explores a temporal attention (TA) mechanism of deep learning to predict COVID-19 disease severity, clinical outcomes, and Spike antibody levels by screening serological indicators over time.

METHODS

We use feature selection techniques to filter feature subsets that are highly correlated with the target. The specific deep Long Short-Term Memory (LSTM) models are employed to capture the dynamic changes of disease severity, clinical outcome, and Spike antibody level. We also propose deep LSTMs with a TA mechanism to emphasize the later blood test records because later records often attract more attention from doctors.

RESULTS

Risk factors highly correlated with COVID-19 are revealed. LSTM achieves the highest classification accuracy for disease severity prediction. Temporal Attention Long Short-Term Memory (TA-LSTM) achieves the best performance for clinical outcome prediction. For Spike antibody level prediction, LSTM achieves the best permanence.

CONCLUSION

The experimental results demonstrate the effectiveness of the proposed models. The proposed models can provide a computer-aided medical diagnostics system by simply using time series of serological indicators.

Diagnostic performance of chest CT average intensity projection (AIP) reconstruction for the assessment of pleuro-parenchymal abnormalities

AIM

The comparison between chest x-ray (CXR) and computed tomography (CT) images is commonly required in clinical practice to assess the evolution of chest pathological manifestations. Intrinsic differences between the two techniques, however, limit reader confidence in such a comparison. CT average intensity projection (AIP) reconstruction allows obtaining "synthetic" CXR (s-CXR) images, which are thought to have the potential to increase the accuracy of comparison between CXR and CT imaging. We aim at assessing the diagnostic performance of s-CXR imaging in detecting common pleuro-parenchymal abnormalities.

MATERIALS AND METHODS

142 patients who underwent chest CT examination and CXR within 24 hours were enrolled. CT was the standard of reference. Both conventional CXR (c-CXR) and s-CXR images were retrospectively reviewed for the presence of consolidation, nodule/mass, linear opacities, reticular opacities, and pleural effusion by 3 readers in two separate sessions. Sensitivity, specificity, accuracy and their 95% confidence interval were calculated for each reader and setting and tested by McNemar test. Inter-observer agreement was tested by Cohen's K test and its 95%CI.

RESULTS

Overall, s-CXR sensitivity ranged 45-67% for consolidation, 12-28% for nodule/mass, 17-33% for linear opacities, 2-61% for reticular opacities, and 33-58% for pleural effusion; specificity 65-83%, 83-94%, 94-98%, 93-100% and 79-86%; accuracy 66-68%, 74-79%, 89-91%, 61-65% and 68-72%, respectively. K values ranged 0.38-0.50, 0.05-0.25, -0.05-0.11, -0.01-0.15, and 0.40-0.66 for consolidation, nodule/mass, linear opacities, reticular opacities, and pleural effusion, respectively.

CONCLUSION

S-CXR images, reconstructed with AIP technique, can be compared with conventional images in clinical practice and for educational purposes.

Deep learning-based prognostication in idiopathic pulmonary fibrosis using chest radiographs

OBJECTIVES

To develop and validate a deep learning-based prognostic model in patients with idiopathic pulmonary fibrosis (IPF) using chest radiographs.

METHODS

To develop a deep learning-based prognostic model using chest radiographs (DLPM), the patients diagnosed with IPF during 2011-2021 were retrospectively collected and were divided into training (n = 1007), validation (n = 117), and internal test (n = 187) datasets. Up to 10 consecutive radiographs were included for each patient. For external testing, three cohorts from independent institutions were collected (n = 152, 141, and 207). The discrimination performance of DLPM was evaluated using areas under the time-dependent receiver operating characteristic curves (TD-AUCs) for 3-year survival and compared with that of forced vital capacity (FVC). Multivariable Cox regression was performed to investigate whether the DLPM was an independent prognostic factor from FVC. We devised a modified gender-age-physiology (GAP) index (GAP-CR), by replacing DLCO with DLPM.

RESULTS

DLPM showed similar-to-higher performance at predicting 3-year survival than FVC in three external test cohorts (TD-AUC: 0.83 [95% CI: 0.76-0.90] vs. 0.68 [0.59-0.77], p < 0.001; 0.76 [0.68-0.85] vs. 0.70 [0.60-0.80], p = 0.21; 0.79 [0.72-0.86] vs. 0.76 [0.69-0.83], p = 0.41). DLPM worked as an independent prognostic factor from FVC in all three cohorts (ps < 0.001). The GAP-CR index showed a higher 3-year TD-AUC than the original GAP index in two of the three external test cohorts (TD-AUC: 0.85 [0.80-0.91] vs. 0.79 [0.72-0.86], p = 0.02; 0.72 [0.64-0.80] vs. 0.69 [0.61-0.78], p = 0.56; 0.76 [0.69-0.83] vs. 0.68 [0.60-0.76], p = 0.01).

CONCLUSIONS

A deep learning model successfully predicted survival in patients with IPF from chest radiographs, comparable to and independent of FVC.

CLINICAL RELEVANCE STATEMENT

Deep learning-based prognostication from chest radiographs offers comparable-to-higher prognostic performance than forced vital capacity.

KEY POINTS

• A deep learning-based prognostic model for idiopathic pulmonary fibrosis was developed using 6063 radiographs. • The prognostic performance of the model was comparable-to-higher than forced vital capacity, and was independent from FVC in all three external test cohorts. • A modified gender-age-physiology index replacing diffusing capacity for carbon monoxide with the deep learning model showed higher performance than the original index in two external test cohorts.

Testicular seminoma presenting as a large conglomerate mass in abdomen

Testicular seminoma commonly occurs in young men aged between 15 and 45 years old. Those with testicular cancer may present with a lump or swelling in the testicle. If treated and managed early, patients can expect a greater than 95% success rate. However, advanced stages of testicular seminoma can lead to eventual metastasis. We present a 45-year-old male patient with a prior history of testicular seminoma who was admitted to the emergency department with abdominal distension and acute abdominal pain. The CT identified a rather sizable abdominal mass and the biopsy confirmed metastatic testicular seminoma. Lymphoma was considered as the other differential diagnosis. Abdominal metastasis is rare in patients with testicular seminoma and usually leads to a poor survival outcome. Our patient did not attend follow-up appointments postorchidectomy, likely resulting in abdominal metastasis of testicular seminoma. This demonstrates the importance of ongoing surveillance of seminoma patients, and the challenges associated with differentiating large abdominal conglomerate mass in the CT scan. This patient is currently on active chemotherapy with bleomycin, cisplatin, and etoposide.

Utilization of SmartNav technology in cochlear implantation: optimizing efficiency in assessment of electrode placement

OBJECTIVES

Proper electrode placement is essential for favorable hearing outcomes following cochlear implantation. Though often used, traditional intraoperative X-ray imaging is time consuming, exposes patients and staff to radiation, and poses interpretational challenges. The Nucleus® SmartNav System, utilizes electrode voltage telemetry (EVT) to analyze the positioning of the electrode array intraoperatively. This study investigates the efficacy of SmartNav in optimizing the efficiency and accuracy of assessing electrode placement.

METHODS

This prospective clinical study analyzed placement of 50 consecutive Cochlear Corporation cochlear implants conducted at a single institution between March of 2022 and June of 2023. Placement check of electrode array using SmartNav and X-ray was completed and individually assessed. A comparative analysis of SmartNav and X-ray completion times for electrode placement assessment was conducted.

RESULTS

Subjects included nine ears with abnormal anatomy and three reimplants. SmartNav placement check required a total time of 2.12 min compared to X-ray imaging at 14.23 min (p = 1.6E-16, CI 95%). Both SmartNav and X-ray had excellent sensitivity of 100% in identifying appropriate electrode position (p = 1.0). Tip fold-over was identified using both modalities in 3 cases with noted easier interpretation using SmartNav.

CONCLUSION

The Nucleus® SmartNav System significantly outperformed traditional X-ray imaging, offering a faster and more straightforward approach to assessing electrode positioning during cochlear implant surgery, thereby enhancing surgical efficiency and patient safety.

Application of emerging technologies in ischemic stroke: from clinical study to basic research

Stroke is a primary cause of noncommunicable disease-related death and disability worldwide. The most common form, ischemic stroke, is increasing in incidence resulting in a significant burden on patients and society. Urgent action is thus needed to address preventable risk factors and improve treatment methods. This review examines emerging technologies used in the management of ischemic stroke, including neuroimaging, regenerative medicine, biology, and nanomedicine, highlighting their benefits, clinical applications, and limitations. Additionally, we suggest strategies for technological development for the prevention, diagnosis, and treatment of ischemic stroke.

Automated radiographic hip morphology measurements: An open-access method

Objective

The aim of this study is to present a newly developed automated method to determine radiographic measurements of hip morphology on dual-energy x-ray absorptiometry (DXA) images. The secondary aim was to compare the performance of the automated and manual measurements.

Design

30 DXA scans from 13-year-olds of the prospective population-based cohort study Generation R were randomly selected. The hip shape was outlined automatically using radiographic landmarks from which the acetabular depth-width ratio (ADR), acetabular index (AI), alpha angle (AA), Wiberg and lateral center edge angle (WCEA) (LCEA), extrusion index (EI), neck-shaft angle (NSA), and the triangular index (TI) were determined. Manual assessments were performed twice by two orthopedic surgeons. The agreement within and between observers and methods was visualized using Bland-Altman plots, and the reliability was studied using the intraclass correlation coefficient (ICC) with 95 % confidence intervals (CI).

Results

The automated method was able to perform all radiographic hip morphology measurements. The intermethod reliability between the automated and manual measurements ranged from 0.57 to 0.96 and was comparable to or better than the manual interobserver reliability, except for the AI.

Conclusion

This open-access, automated method allows fast and reproducible calculation of radiographic measurements of hip morphology on right hip DXA images. It is a promising tool for performing automated radiographic measurements of hip morphology in large population studies and clinical practice.

Comparing fetal phantoms with surrogate organs in female phantoms during CT exposure of pregnant patients

With the rising use of Computed Tomography (CT) in diagnostic radiology, there are concerns regarding radiation exposure to sensitive groups, including pregnant patients. Accurately determining the radiation dose to the fetus during CT scans is essential to balance diagnostic efficacy with patient safety. This study assessed the accuracy of using the female uterus as a surrogate for fetal radiation dose during CT imaging. The study used common CT protocols to encompass various scenarios, including primary beam, scatter, and partial exposure. The computational program NCICT was used to calculate radiation doses for an adult female and a fetus phantom. The study highlighted that using the uterus for dose estimation can result in consistent underestimations of the effective dose, particularly when the fetus lies within the primary radiation beam. These discrepancies may influence clinical decisions, affecting care strategies and perceptions of associated risks. In conclusion, while the female uterus can indicate fetal radiation dose if the fetus is outside the primary beam, it is unreliable when the fetus is within the primary beam. More reliable abdomen/pelvic organs were recommended.

Development of new techniques and clinical applications of liquid biopsy in lung cancer management

Lung cancer is an exceedingly malignant tumor reported as having the highest morbidity and mortality of any cancer worldwide, thus posing a great threat to global health. Despite the growing demand for precision medicine, current methods for early clinical detection, treatment and prognosis monitoring in lung cancer are hampered by certain bottlenecks. Studies have found that during the formation and development of a tumor, molecular substances carrying tumor-related genetic information can be released into body fluids. Liquid biopsy (LB), a method for detecting these tumor-related markers in body fluids, maybe a way to make progress in these bottlenecks. In recent years, LB technology has undergone rapid advancements. Therefore, this review will provide information on technical updates to LB and its potential clinical applications, evaluate its effectiveness for specific applications, discuss the existing limitations of LB, and present a look forward to possible future clinical applications. Specifically, this paper will introduce technical updates from the prospectives of engineering breakthroughs in the detection of membrane-based LB biomarkers and other improvements in sequencing technology. Additionally, it will summarize the latest applications of liquid biopsy for the early detection, diagnosis, treatment, and prognosis of lung cancer. We will present the interconnectedness of clinical and laboratory issues and the interplay of technology and application in LB today.

Role of follow-up gallium scintigraphy in the evaluation of malignant external otitis (skull base osteomyelitis): A case report

Malignant otitis externa (skull base osteomyelitis) can be fatal and long-term antibiotic therapy is recommended. Despite being potentially fatal, this infection causes minor changes in inflammatory biomarkers (white blood cell count and C-reactive protein levels) upon blood testing. Computed tomography and magnetic resonance imaging changes persist over a long period. Therefore, it is difficult to determine the optimal time for the discontinuation of antibiotics. We present a 77-year-old male whose medical history included type 2 diabetes mellitus who suffered from chronic otitis media with Pseudomonas aeruginosa infection. His condition did not improve with proper treatment, and imaging revealed malignant otitis media. Intravenous cefepime treatment was administered. Antibiotic treatment was de-escalated to oral levofloxacin treatment after Gallium-67 scintigraphy showed less accumulation after 6 weeks of Cefepime administration; accumulation almost disappeared after 1 year. In this report, we describe the usefulness of gallium scintigraphy in the evaluation of malignant otitis externa.

Age assessment in unaccompanied minors: assessing uniformity of protocols across Europe

Age assessment of migrants is crucial, particularly for unaccompanied foreign minors, a population facing legal, social, and humanitarian challenges. Despite existing guidelines, there is no unified protocol in Europe for age assessment.The Forensic Anthropology Society of Europe (FASE) conducted a comprehensive questionnaire to understand age estimation practices in Europe. The questionnaire had sections focusing on the professional background of respondents, annual assessment numbers, requesting parties and reasons, types of examinations conducted (e.g., physical, radiological), followed protocols, age estimation methods, and questions on how age estimates are reported.The questionnaire's findings reveal extensive engagement of the forensic community in age assessment in the living, emphasizing multidisciplinary approaches. However, there seems to be an incomplete appreciation of AGFAD guidelines. Commonalities exist in examination methodologies and imaging tests. However, discrepancies emerged among respondents regarding sexual maturity assessment and reporting assessment results. Given the increasing importance of age assessment, especially for migrant child protection, the study stresses the need for a unified protocol across European countries. This can only be achieved if EU Member States wholeheartedly embrace the fundamental principles outlined in EU Directives and conduct medical age assessments aligned with recognized standards such as the AGFAD guidelines.

No Value Found With Routine Early Postoperative Radiographs after Implant Removal in Pediatric Patients

BACKGROUND

Implants are routinely removed in pediatric patients. Fracture through the prior implant site is a common worry after implant removal. Early post-implant removal radiographs are routinely used to evaluate the prior implant removal sites and to assess when a patient may return to normal activities. To our knowledge, the value of early, routine postoperative radiographs after elective implant removal in pediatric patients has not been studied.

METHODS

A retrospective patient cohort of pediatric patients who had implant removal from an extremity from 2017 to 2019 was used in this study. Data were collected for patient demographics, implant site, reason for primary surgery, complications, number of postoperative radiographs, radiation exposure, cost of imaging, and whether the postoperative plan was changed by imaging.

RESULTS

Two hundred ninety patients were included in the study. Postoperative plans were changed only in 0.69% of patients (n = 2) because of abnormal 2-week radiographs and 1.72% (n = 5) because of abnormal 6-week radiographs. However, the event's proportion difference (change of management) was not statically significant ( P = 0.182) between those who had a radiograph obtained and those who did not. The mean follow-up time was 16 months. The mean number of postoperative radiographs obtained was 3.74, the mean cost per radiograph was $103, and the mean postoperative radiation exposure was 1.34 mSv. No fractures were observed after implant removal.

DISCUSSION

A retrospective review of the value of early, postoperative radiographs after routine orthopaedic implant removal found that postoperative radiographs at 2 and 6 weeks did not change the postoperative plan for most of the patients. Postoperative radiographs have an average cost of $103, and radiation exposure equal to approximately 6 months of natural background radiation.

LEVEL OF EVIDENCE

Level III.

Assessment of radiation in fishes derived from radiocesium in the port of Fukushima Daiichi nuclear power plant

This study established specialized radiation dose models to evaluate the internal radiation doses derived from 137Cs and 134Cs in fishes in the port of the Fukushima Daiichi Nuclear Power Plant from 2012 to 2023. By August 2018, the activities of 134Cs and 137Cs in fishes decreased at the T1/2 of 176 d and 191 d, respectively. The corresponding mass concentrations were far lower than 1 mg/kg and the chemical toxicity can be negligible. Regarding radiotoxicity, 18,000 Bq/kgfresh weight of 134Cs and 137Cs in grouper Sebastes schlegelii produced 276 μGy/h of radiation dose, which was below the no-effect-dose-rate benchmarks (400 μGy/h). 740,000 Bq/kgfresh weight of 134Cs and 137Cs in greenling Hexagrammos otakii produced 12,600 μGy/h of radiation dose, which was much higher than 400 μGy/h, indicating the possibility of radiation effects. If a person eats these two reported fishes, the resulting committed effective doses for humans are 7.7 μSv and 6.31 mSv, respectively.

Influence of deep learning image reconstruction algorithm for reducing radiation dose and image noise compared to iterative reconstruction and filtered back projection for head and chest computed tomography examinations: a systematic review

Background

The most recent advances in Computed Tomography (CT) image reconstruction technology are Deep learning image reconstruction (DLIR) algorithms. Due to drawbacks in Iterative reconstruction (IR) techniques such as negative image texture and nonlinear spatial resolutions, DLIRs are gradually replacing them. However, the potential use of DLIR in Head and Chest CT has to be examined further. Hence, the purpose of the study is to review the influence of DLIR on Radiation dose (RD), Image noise (IN), and outcomes of the studies compared with IR and FBP in Head and Chest CT examinations.

Methods

We performed a detailed search in PubMed, Scopus, Web of Science, Cochrane Library, and Embase to find the articles reported using DLIR for Head and Chest CT examinations between 2017 to 2023. Data were retrieved from the short-listed studies using Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines.

Results

Out of 196 articles searched, 15 articles were included. A total of 1292 sample size was included. 14 articles were rated as high and 1 article as moderate quality. All studies compared DLIR to IR techniques. 5 studies compared DLIR with IR and FBP. The review showed that DLIR improved IQ, and reduced RD and IN for CT Head and Chest examinations.

Conclusions

DLIR algorithm have demonstrated a noted enhancement in IQ with reduced IN for CT Head and Chest examinations at lower dose compared with IR and FBP. DLIR showed potential for enhancing patient care by reducing radiation risks and increasing diagnostic accuracy.