Dual-Energy CT of Pediatric Abdominal Oncology Imaging: Private Tour of New Applications of CT Technology.

OBJECTIVE. Dual-energy CT is gaining increasing recognition as a valuable diagnostic tool for assessing abdominal neoplasms. Nevertheless, much of the literature has focused on its use in adults. This review article illustrates specific tools available with dual-energy CT in the evaluation of pediatric abdominal neoplasms. Additionally, common imaging artifacts and pitfalls in dual-energy CT of the pediatric abdomen are outlined. CONCLUSION. Dual-energy CT can augment diagnostic yield in the imaging evaluation of pediatric abdominal neoplasms.

A Universal Protocol for Abdominal CT Examinations Performed on a Photon-Counting Detector CT System: A Feasibility Study.

OBJECTIVE: The aims of this study were to investigate the feasibility of using a universal abdominal acquisition protocol on a photon-counting detector computed tomography (PCD-CT) system and to compare its performance to that of single-energy (SE) and dual-energy (DE) CT using energy-integrating detectors (EIDs). METHODS: Iodine inserts of various concentrations and sizes were embedded into different sizes of adult abdominal phantoms. Phantoms were scanned on a research PCD-CT and a clinical EID-CT with SE and DE modes. Virtual monoenergetic images (VMIs) were generated from PCD-CT and DE mode of EID-CT. For each image type and phantom size, contrast-to-noise ratio (CNR) was measured for each iodine insert and the area under the receiver operating characteristic curve (AUC) for iodine detectability was calculated using a channelized Hotelling observer. The optimal energy (in kiloelectrovolt) of VMIs was determined separately as the one with highest CNR and the one with the highest AUC. The PCD-CT VMIs at the optimal energy were then compared with DE VMIs and SE images in terms of CNR and AUC. RESULTS: Virtual monoenergetic image at 50 keV had both the highest CNR and highest AUC for PCD-CT and DECT. For 1.0 mg I/mL iodine and 35 cm phantom, the CNRs of 50 keV VMIs from PCD-CT (2.01 ± 0.67) and DE (1.96 ± 0.52) were significantly higher (P < 0.001, Wilcoxon signed-rank test) than SE images (1.11 ± 0.35). The AUC of PCD-CT (0.98 ± 0.01) was comparable to SE (0.98 ± 0.01), and both were slightly lower than DE (0.99 ± 0.01, P < 0.01, Wilcoxon signed-rank test). A similar trend was observed for other phantom sizes and iodine concentrations. CONCLUSIONS: Virtual monoenergetic images at a fixed energy from a universal acquisition protocol on PCD-CT demonstrated higher iodine CNR and comparable iodine detectability than SECT images, and similar performance compared with DE VMIs.

Comparison of image quality between split-filter twin beam dual energy and single energy images in abdominal CT.

PURPOSE: To compare the objective and subjective image quality between composed images from split-filter twin beam dual energy (TBDE) and single-energy computed tomography (SECT) in abdominal CT. METHODS: In this prospective study, 103 patients were imaged using TBDE (n = 51) or SECT (n = 52). The CT number and noise were measured for the following six abdominal structures: liver, spleen, fat, muscle, aorta and portal vein. The normalised noise level for the liver was separately measured and compared. The consistency of the SNR and CT number was compared between the two groups. The subjective image quality was evaluated using six aspects in a blinded manner. Cohen's Kappa statistic was used to determine the level of agreement between the two radiologists. RESULTS: For the objective image quality comparison, the SNR of all structures was higher using TBDE compared to SECT (p < 0.05). The CT value for different structures were comparable between the two groups (p > 0.05). Among all patient sizes, the noise level for TBDE images was significantly lower (7-17% reduction) compared to the SECT images (p < 0.01). Furthermore, noise reduction's magnitude increases with body size. For image quality's subjective evaluation, TBDE images are superior for certain aspects. Cohen's Kappa values (0.7634-0.8460) suggest an adequate level of agreement between the two observers. CONCLUSIONS: TBDE scan mode can yield similar or even better objective and subjective image quality at the same level of radiation than conventional SECT. Quantitatively, TBDE images have a 7-17% reduction in noise, depending on the size of the scanned body regions.

Feasibility study of a double resonant (1H/23Na) abdominal RF setup at 3T.

Sodium magnetic resonance imaging (MRI) of the human abdomen is of increasing clinical interest for e.g. kidney, intervertebral disks, prostate and tumor monitoring examinations in the abdomen. To overcome the low MR sensitivity of sodium, optimal radio frequency (RF) structures should be used. A common approach is to combine a volumetric transmit coil for homogeneous excitation with an array of sensitive receive coils adapted to the human shape. Additionally, proton imaging is required to match the physiological sodium images to the morphological proton images. In this work, we demonstrated the feasibility of a double resonant proton/sodium RF setup for abdominal MRI at 3T, providing a high sodium sensitivity. After extensive simulations, a 16-channel sodium receive array was built and used in combination with a volumetric sodium transmit coil. Additionally, a local proton coil was included in the setup for anatomical localizations. The setup was investigated using electromagnetic field simulations, phantom measurements and final in-vivo measurements of a healthy volunteer. A 3 to 6-fold sensitivity improvement of the sodium receive array compared to the volumetric sodium coil was achieved using the phantom simulations and measurements. Safety assessments of the local proton transmit/receive coil were performed using specific absorption rate simulations. Finally, the feasibility of such a setup was proven by in-vivo measurements.

Prevalence and Severity of Off-Centering During Diagnostic CT: Observations From 57,621 CT scans of the Chest, Abdomen, and/or Pelvis.

PURPOSE: To determine distances between patient centroid and gantry isocenter during CT imaging of the chest, abdomen, and/or pelvis, and to evaluate differences based on patient gender, scan region, patient position, and gantry aperture. MATERIALS AND METHODS: A water phantom and an anthropomorphic phantom were imaged in the centered position in the CT gantry and at several off-centered positions. Additionally, data from 57,621 adult chest, abdomen, and/or pelvic CT acquisitions were evaluated. Data were analyzed with an analysis of variance using the centroid-to-isocenter data as the dependent variable and the other parameters as independent variables. RESULTS: The majority of patient acquisitions (83.7% (48271/57621)) were performed with the patient's centroid positioned below isocenter (mean 1.7 cm below isocenter (SD 1.8 cm); range 12.1 cm below to 7.8 cm above isocenter). Off-centering in the x-axis was less severe (mean 0.01 cm left of isocenter (SD 1.6 cm)). Distance between centroid and isocenter in the y-axis did not differ as a function of sex but did differ based on scan region, patient position, and gantry aperture. CONCLUSION: Off-centering is common during CT imaging and has been previously demonstrated to impact dose and image quality.

A phantom study of the performance of model-based iterative reconstruction in low-dose chest and abdominal CT: When are benefits maximized?

INTRODUCTION: The aim of this study was to assess and compare the effects of CT image reconstruction techniques on low-dose CT image quality using phantoms. METHODS: Anthropomorphic torso and spatial/contrast-resolution phantoms were scanned at decreasing tube currents between 400 and 10 mA. CT thorax and abdomen/pelvis series were reconstructed with filtered back projection (FBP) alone, combined 40% adaptive statistical iterative reconstruction & FBP (ASIR40), and model-based iterative reconstruction (MBIR) [(resolution-preference 05 (RP05) and RP20 in the thorax and RP05 and noise-reduction 05 (NR05) in the abdomen)]. Two readers rated image quality quantitatively and qualitatively. RESULTS: In thoracic CT, objective image noise on MBIR RP05 data sets outperformed FBP at 200, 100, 50 and 10 mA and outperformed ASIR40 at 50 and 10 mA (p < 0.001). MBIR RP20 outperformed FBP at 50 and 10 mA and outperformed ASIR40 at 10 mA (p < 0.001). Compared with both FBP and ASIR40, MBIR RP05 demonstrated significantly better signal-to-noise ratio (SNR) at 10 mA. In abdomino-pelvic CT, MBIR RP05 and NR05 outperformed FBP and ASIR at all tube current levels for objective image noise. NR05 demonstrated greater SNR at 200, 100, 50 and 10 mA and RP05 demonstrated greater SNR at 50 and 10 mA compared with both FBP and ASIR. MBIR images demonstrated better subjective image quality scores. Spatial resolution, low-contrast detectability and contrast-to-noise ratio (CNR) were comparable between image reconstruction techniques. CONCLUSION: CTs reconstructed with MBIR have lower image noise and improved image quality compared with FBP and ASIR. These effects increase with reduced radiation exposure confirming optimal use for low-dose CT imaging.

Portable abdomen radiography: moving to thickness-based protocols.

BACKGROUND: Default pediatric protocols on many digital radiography systems are configured based on patient age. However, age does not adequately characterize patient size, which is the principal determinant of proper imaging technique. Use of default pediatric protocols by inexperienced technologists can result in patient overexposure, inadequate image quality, or repeated examinations. OBJECTIVE: To ensure diagnostic image quality at a well-managed patient radiation exposure by transitioning to thickness-based protocols for pediatric portable abdomen radiography. MATERIALS AND METHODS: We aggregated patient thickness data, milliamperes (mAs), kilovoltage peak (kVp), exposure index (EI), source-to-detector distance, and grid use for all portable abdomen radiographs performed in our pediatric hospital in a database with a combination of automated and manual data collection techniques. We then analyzed the database and used it as the basis to construct thickness-based protocols with consistent image quality across varying patient thicknesses, as determined by the EI. RESULTS: Retrospective analysis of pediatric portable exams performed at our adult-focused hospitals demonstrated substantial variability in EI relative to our pediatric hospital. Data collection at our pediatric hospital over 4 months accumulated roughly 800 portable abdomen exams, which we used to develop a thickness-based technique chart. CONCLUSION: Through automated retrieval of data in our systems' digital radiography exposure logs and recording of patient abdomen thickness, we successfully developed thickness-based techniques for portable abdomen radiography.

Utilidad de la ecografía a pie de cama en el body packer / Usefulness of bedside ultrasound in body packer syndrome

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Quality of routine diagnostic abdominal images generated from a novel detector-based spectral CT scanner: a technical report on a phantom and clinical study.

PURPOSE: To evaluate the image quality of routine diagnostic images generated from a novel detector-based spectral detector CT (SDCT) and compare it with CT images obtained from a conventional scanner with an energy-integrating detector (Brilliance iCT), Routine diagnostic (conventional/polyenergetic) images are non-material-specific images that resemble single-energy images obtained at the same radiation, METHODS: ACR guideline-based phantom evaluations were performed on both SDCT and iCT for CT adult body protocol. Retrospective analysis was performed on 50 abdominal CT scans from each scanner. Identical ROIs were placed at multiple locations in the abdomen and attenuation, noise, SNR, and CNR were measured. Subjective image quality analysis on a 5-point Likert scale was performed by 2 readers for enhancement, noise, and image quality. RESULTS: On phantom studies, SDCT images met the ACR requirements for CT number and deviation, CNR and effective radiation dose. In patients, the qualitative scores were significantly higher for the SDCT than the iCT, including enhancement (4.79 ± 0.38 vs. 4.60 ± 0.51, p = 0.005), noise (4.63 ± 0.42 vs. 4.29 ± 0.50, p = 0.000), and quality (4.85 ± 0.32, vs. 4.57 ± 0.50, p = 0.000). The SNR was higher in SDCT than iCT for liver (7.4 ± 4.2 vs. 7.2 ± 5.3, p = 0.662), spleen (8.6 ± 4.1 vs. 7.4 ± 3.5, p = 0.152), kidney (11.1 ± 6.3 vs. 8.7 ± 5.0, p = 0.033), pancreas (6.90 ± 3.45 vs 6.11 ± 2.64, p = 0.303), aorta (14.2 ± 6.2 vs. 11.0 ± 4.9, p = 0.007), but was slightly lower in lumbar-vertebra (7.7 ± 4.2 vs. 7.8 ± 4.5, p = 0.937). The CNR of the SDCT was also higher than iCT for all abdominal organs. CONCLUSION: Image quality of routine diagnostic images from the SDCT is comparable to images of a conventional CT scanner with energy-integrating detectors, making it suitable for diagnostic purposes.

Endoscopic removal of multiple sharp gastro-duodenal foreign bodies

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Consistent low-contrast detectability for variable patient sizes and corresponding dose in abdominal CT.

PURPOSE: For CT dose optimization, one needs to address two important questions. The first is how various lesion-specific detection tasks demand different patient doses for the same patient. The second is how the variation of the patient size requires different patient doses for the same lesion detection task. In this study, we attempted to find quantitative solutions to these questions by utilizing a wide range of abdomen phantoms. METHODS: A simplified model with a monochromatic fan beam passing through a bowtie-filter and an elliptical object was proposed. The model relates the minimum detectable contrast (MDC) to the size-specific dose by power index of -1/2 and to the lesion size by power index of -1 with a patient size dependence function (PSDF) as the proportionality factor. The experimental validation was performed using seven abdomen phantoms (lateral ranges: 10 cm-39 cm) scanned with helical modes at various dose levels on two 64-slice scanners (Siemens mCT and GE HD 750). Noise images were obtained using subtractions among adjacent slices in the images reconstructed with filtered backprojection. It was verified that the mean pixel value distributions from various small regions (1.8 mm-10 mm) are Gaussian, thus the concept of the statistically defined minimum detectable contrast (SD-MDC), defined as distribution's standard deviation multiplied by 3.29, can be applied. The impact of the helical pitch and the high-definition (HD) acquisition was also studied. RESULTS: The experimental data from all phantoms were found to fit the power law well (R2  ≥ 0.983). The PSDF was found to be scanner dependent - modeled with a Gaussian amplifier (R2  = 0.983) for one manufacturer and with an exponential function for the other (R2  = 0.990). The MDC relationship was not found to be impacted by different pitches or by HD acquisition. The results were used to find the size-specific doses and corresponding acquisition techniques required by consistent low-contrast detectability for variable patient sizes. Visual comparisons on the low-contrast insert images demonstrated that the derived techniques delivered consistent low-contrast detectability. CONCLUSIONS: We have modeled and verified the relationship of the minimum detectable contrast to the patient size, the patient dose, and the lesion size from the images reconstructed with filtered backprojection. The findings can be useful for task-specific dose modulation on abdomen CT studies.

Variability of CT Attenuation Measurements in Virtual Unenhanced Images Generated Using Multimaterial Decomposition from Fast Kilovoltage-switching Dual-energy CT.

RATIONALE AND OBJECTIVES: To compare Hounsfield unit (HU) data obtained from true-unenhanced (TUE) and virtual-unenhanced (VUE) imaging obtained with a fast kv-switching dual-energy computed tomography (CT) scanner using multimaterial decomposition algorithm. MATERIALS AND METHODS: In this Institutional Review Board-approved, Health Insurance Portability and Accountability Act-compliant, retrospective cohort study, CT scans of 19 patients undergoing multiphasic renal protocol abdominal CT on a fast kv-switching dual-energy CT scanner were reviewed. CT numbers were measured on the matched TUE and VUE generated using a multimaterial decomposition algorithm with selective iodine suppression, and postcontrast images at predefined locations in seven organs. Six hundred sixty regions of interest were placed at 132 locations. Agreement was assessed with paired t test, Pearson's correlation, and Bland-Altman analysis. RESULTS: Mean TUE and VUE measurements were not significantly different in the corticomedullary (P = 0.25) or nephrographic (P = 0.10) phases. There was a strong correlation between TUE and VUE CT numbers (corticomedullary: r = 0.90, nephrographic: r = 0.90, each P < 0.001). Discrepancies ≥5 HU occurred 46 times (35%, 46 of 132) in the corticomedullary phase and 44 times (33%, 44 of 132) in the nephrographic phase. Discrepancies ≥10 HU occurred in 7% (9 of 132 in both corticomedullary and nephrographic phases). Interphase, intrasubject VUE CT numbers were strongly correlated (r = 0.93, P < 0.001), but discrepancies ≥5 HU (22% [29 of 132]) and ≥10 HU (2% [3 of 132]) occurred. There was no significant correlation between the true postcontrast CT number and the magnitude of VUE-TUE discrepancy (r = -0.04, P = 0.6). CONCLUSION: CT numbers on VUE images generated from fast kv-switching dual-energy CT scans strongly correlate with TUE CT numbers on a population basis, but commonly vary 5-9 HU on a per-patient basis.

Enfermedad de Hirschsprung en el adulto que debuta como obstrucción intestinal aguda. A propósito de un caso / Hirschsprung disease with debut in adult age as acute intestinal obstruction: case report

La enfermedad de Hirschsprung consiste en la ausencia de células ganglionares en los plexos submucosos y mientérico del intestino. Suele diagnosticarse en el periodo neonatal, siendo muy poco frecuente que se descubra en el adulto. Suele presentarse como estreñimiento severo con dilatación cólica proximal al segmento agangliónico. El tratamiento es quirúrgico, extirpando el segmento agangliónico y restableciendo la continuidad del tubo digestivo. En muy raras ocasiones, esta enfermedad se presenta como un cuadro de obstrucción intestinal aguda. Presentamos el caso de un paciente, no diagnosticado previamente, que debutó como un cuadro de dilatación cólica masiva, con un diámetro máximo de 44 cm, con riesgo de perforación inminente, lo que motivó la realización de una cirugía urgente. Incluimos una revisión de la literatura existente al respecto (AU)

Hirschsprung's disease is characterized by absence of ganglion cells in submucosal and myenteric plexus of distal bowel. Most cases become manifest during the neonatal period, but in rare instances, this disease is initially diagnosed in adult age. It usually presents as severe constipation with colonic dilatation proximal to the aganglionic segment. The treatment is surgical, removing the aganglionic segment and restoring continuity of digestive tract. The disease rarely presents as an acute intestinal obstruction. We report a case not previously diagnosed, which presented as a massive colonic dilatation with a maximum diameter of 44 cm, with imminent risk of drilling that forced to perform an emergency surgery. We include a review of existing literature (AU)

Liposarcoma retroperitoneal gigante: el tumor silencioso / Giant retroperitoneal liposarcoma: The silent tumour

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Upper limits of the photon fluence rate on CT detectors: Case study on a commercial scanner.

PURPOSE: The highest photon fluence rate that a computed tomography (CT) detector must be able to measure is an important parameter. The authors calculate the maximum transmitted fluence rate in a commercial CT scanner as a function of patient size for standard head, chest, and abdomen protocols. METHODS: The authors scanned an anthropomorphic phantom (Kyoto Kagaku PBU-60) with the reference CT protocols provided by AAPM on a GE LightSpeed VCT scanner and noted the tube current applied with the tube current modulation (TCM) system. By rescaling this tube current using published measurements on the tube current modulation of a GE scanner [N. Keat, "CT scanner automatic exposure control systems," MHRA Evaluation Report 05016, ImPACT, London, UK, 2005], the authors could estimate the tube current that these protocols would have resulted in for other patient sizes. An ECG gated chest protocol was also simulated. Using measured dose rate profiles along the bowtie filters, the authors simulated imaging of anonymized patient images with a range of sizes on a GE VCT scanner and calculated the maximum transmitted fluence rate. In addition, the 99th and the 95th percentiles of the transmitted fluence rate distribution behind the patient are calculated and the effect of omitting projection lines passing just below the skin line is investigated. RESULTS: The highest transmitted fluence rates on the detector for the AAPM reference protocols with centered patients are found for head images and for intermediate-sized chest images, both with a maximum of 3.4 ⋅ 10(8) mm(-2) s(-1), at 949 mm distance from the source. Miscentering the head by 50 mm downward increases the maximum transmitted fluence rate to 5.7 ⋅ 10(8) mm(-2) s(-1). The ECG gated chest protocol gives fluence rates up to 2.3 ⋅ 10(8) - 3.6 ⋅ 10(8) mm(-2) s(-1) depending on miscentering. CONCLUSIONS: The fluence rate on a CT detector reaches 3 ⋅ 10(8) - 6 ⋅ 10(8) mm(-2) s(-1) in standard imaging protocols, with the highest rates occurring for ECG gated chest and miscentered head scans. These results will be useful to developers of CT detectors, in particular photon counting detectors.

Síndrome de Bouveret / A rare presentation of gallstones: Bouveret´s syndrome, a case report

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El carbonato de lantano tiene una apariencia radiopaca en la radiografía de abdomen / Lanthanum carbonate has a radiopaque appearance on the plain abdominal radiography

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Low-dose abdominal computed tomography for detection of urinary stone disease - Impact of additional spectral shaping of the X-ray beam on image quality and dose parameters.

OBJECTIVES: To evaluate a novel tin filter-based abdominal CT protocol for urolithiasis in terms of image quality and CT dose parameters. METHODS: 130 consecutive patients with suspected urolithiasis underwent non-enhanced CT with three different protocols: 48 patients (group 1) were examined at tin-filtered 150kV (150kV Sn) on a third-generation dual-source-CT, 33 patients were examined with automated kV-selection (110-140kV) based on the scout view on the same CT-device (group 2), and 49 patients were examined on a second-generation dual-source-CT (group 3) with automated kV-selection (100-140kV). Automated exposure control was active in all groups. Image quality was subjectively evaluated on a 5-point-likert-scale by two radiologists and interobserver agreement as well as signal-to-noise-ratio (SNR) was calculated. Dose-length-product (DLP) and volume CT dose index (CTDIvol) were compared. RESULTS: Image quality was rated in favour for the tin filter protocol with excellent interobserver agreement (ICC=0.86-0.91) and the difference reached statistical significance (p<0.001). SNR was significantly higher in group 1 and 2 compared to second-generation DSCT (p<0.001). On third-generation dual-source CT, there was no significant difference in SNR between the 150kV Sn and the automated kV selection protocol (p=0.5). The DLP of group 1 was 23% and 21% (p<0.002) lower in comparison to group 2 and 3, respectively. So was the CTDIvol of group 1 compared to group 2 (-36%) and 3 (-32%) (p<0.001). CONCLUSION: Additional shaping of a 150kV source spectrum by a tin filter substantially lowers patient exposure while improving image quality on un-enhanced abdominal computed tomography for urinary stone disease.

Qué hacer con el recién nacido obstruido / What to do with an obstructed newborn

La obstrucción intestinal es la urgencia abdominal más frecuente en el recién nacido. Su manejo es un desafío tanto para el clínico como para el radiólogo. La presentación clínica no es específica y tanto el diagnóstico como el manejo posterior se apoyan en los estudios de imagen. Los métodos tradicionales para estudiar al recién nacido obstruido han sido la radiografía simple de abdomen y los estudios con contraste del tracto gastrointestinal. La ecografía ha demostrado su utilidad en la obstrucción intestinal, evitando en determinados casos el uso de radiación ionizante, por lo que debería quedar incluida en las estrategias de diagnóstico, como una técnica de estudio inicial. Mediante la combinación adecuada de estas técnicas se podrá llegar al diagnóstico de forma rápida y precisa, orientando el manejo terapéutico del paciente y disminuyendo las complicaciones (AU)

Bowel obstruction is the most common abdominal emergency in newborns. Managing bowel obstruction is a challenge for both clinicians and radiologists. The clinical presentation is nonspecific, and both the diagnosis and subsequent management are based on imaging studies. The traditional approach to studying obstructed newborns consists of plain-film abdominal X-rays and contrast-based studies of the gastrointestinal tract. Ultrasonography has proven useful in bowel obstruction, thus avoiding the use of ionizing radiation in certain cases, so diagnostic strategies should include it as a first-line technique. Using an appropriate combination of these techniques, it is possible to reach an accurate diagnosis quickly, orienting treatment and decreasing complications (AU)

Urgencias abdominales en pediatría / Abdominal emergencies in pediatrics

La sintomatología abdominal es uno de los motivos de consulta más frecuente en la urgencia pediátrica, siendo el dolor abdominal el síntoma más referido. Habitualmente, para el diagnóstico es suficiente con una anamnesis y exploración física precisas. Para el radiólogo es útil conocer cuáles son las patologías abdominales más frecuentes por franjas de edad, lo cual permite acotar el diagnóstico diferencial. Cuando esté indicado realizar alguna prueba de imagen, la ecografía es la técnica inicial en la mayoría de los casos; permite realizar el diagnóstico o añadir información relevante, con las ventajas conocidas de esta técnica. La radiografía simple hoy en día queda reservada cuando existe sospecha de perforación, obstrucción intestinal o ingesta de cuerpo extraño. Conviene recordar, que el dolor abdominal puede ser secundario a una neumonía basal. La TC queda reservada para indicaciones concretas y en casos individualizados. Por ejemplo, en pacientes con alta sospecha clínica de patología abdominal y con hallazgos ecográficos no concluyentes. Se revisan algunas de las patologías más frecuentes en la urgencia pediátrica, las diferentes pruebas de imagen indicadas y la semiología radiológica en las patologías abordadas (AU)

Abdominal symptoms are among the most common reasons for pediatric emergency department visits, and abdominal pain is the most frequently reported symptom. Thorough history taking and physical examination can often reach the correct diagnosis. Knowing the abdominal conditions that are most common in each age group can help radiologists narrow the differential diagnosis. When imaging tests are indicated, ultrasonography is usually the first-line technique, enabling the diagnosis or adding relevant information with the well-known advantages of this technique. Nowadays, plain-film X-ray studies are reserved for cases in which perforation, bowel obstruction, or foreign body ingestion is suspected. It is also important to remember that abdominal pain can also occur secondary to basal pneumonia. CT is reserved for specific indications and in individual cases, for example, in patients with high clinical suspicion of abdominal disease and inconclusive findings at ultrasonography. We review some of the most common conditions in pediatric emergencies, the different imaging tests indicated in each case, and the imaging signs in each condition (AU)