A Novel Magnetic Resonance Quality Assurance Phantom (KMRP-4):Multi-Site Comparison With the American College of Radiology Phantom

Purpose@#To propose a novel standard magnetic resonance imaging (MRI) phantom, hereafter called the Korea Magnetic Resonance Phantom-4th edition (KMRP-4). Its related quality control (QC) assessment protocols and its comparison with the American College of Radiology (ACR) phantom and its QC assessment protocols. @*Materials and Methods@#Internally, the KMRP-4 phantom is composed of cubic and triangular vessels, brain tissue structures, and a uniform region designed to facilitate a variety of QC protocols. Using magnetic resonance (MR) images of these structures, we quantitatively evaluated a total of 10 parameters, seven from those of existing ACR protocols (i.e., geometric accuracy, high-contrast spatial resolution, slice thickness accuracy, slice position accuracy, image intensity uniformity, percent signal ghosting, and low-contrast object detectability) and three additional parameters for evaluating vessel conspicuity, brain tissue contrast, and signal-to-noise ratio (SNR) introduced in the KMRP-4 protocols. Twentytwo MRI systems of 0.32–3.0 T static magnetic field strength were tested using both ACR and KMRP-4 phantoms. Mann–Whitney U-tests were performed on the seven evaluation items of the ACR method to compare KMRP-4 and ACR methods. @*Results@#The results of Mann–Whitney U-test demonstrated that p-values were more than 0.05 for all seven items that could be assessed with both ACR and KMRP-4, indicating similar results between the two methods. Additionally, assessments of vessel conspicuity, brain tissue contrast, and SNR using the KMRP-4 method demonstrated utility of the KMRP-4 phantom. @*Conclusion@#A novel standard phantom and related QC methods were developed to perform objective, observer-independent, and semi-automatic QC tests. Quantitative comparisons of MR images with KMPR-4 and ACR phantoms were performed. Results demonstrated the utility of the newly proposed KMRP-4 phantom and its related QC methods.

A framework for nationwide COVID-19 vaccine safety research in the Republic of Korea: the COVID-19 Vaccine Safety Research Committee

With the introduction of coronavirus disease 2019 (COVID-19) vaccines, the Korea Disease Control and Prevention Agency (KDCA) commissioned the National Academy of Medicine of Korea to gather experts to independently assess post-vaccination adverse events. Accordingly, the COVID-19 Vaccine Safety Research Committee (CoVaSC) was launched in November 2021 to perform safety studies and establish evidence for policy guidance. The CoVaSC established 3 committees for epidemiology, clinical research, and communication. The CoVaSC mainly utilizes pseudonymized data linking KDCA’s COVID-19 vaccination data and the National Health Insurance Service’s claims data. The CoVaSC’s 5-step research process involves defining the target diseases and organizing ad-hoc committees, developing research protocols, performing analyses, assessing causal relationships, and announcing research findings and utilizing them to guide compensation policies. As of 2022, the CoVaSC completed this research process for 15 adverse events. The CoVaSC launched the COVID-19 Vaccine Safety Research Center in September 2022 and has been reorganized into 4 divisions to promote research including international collaborative studies, long-/short-term follow-up studies, and education programs. Through these enhancements, the CoVaSC will continue to swiftly provide scientific evidence for COVID-19 vaccine research and compensation and may serve as a model for preparing for future epidemics of new diseases.

Development of Entrustable Professional Activity, Core Competencies, and Guidelines in 2021 Radiology Competency Education Project

To provide high-quality training to residents in a rapidly changing medical environment, it is very important to improve the annual training curriculum centered on competency and ensure that training hospitals maintain an environment suitable for training. The Korean Society of Radiology (KSR) has been steadily improving the training system and has suggested the improvement of the training system by strengthening the competency-based evaluation and faculty development. Currently, KSR was selected for the second annual training curriculum systematization construction project in July 2021, and developed entrustable professional activities, core competencies, and assessment guidelines required by the construction project. Therefore, the development process and assessment guidelines will be introduced to residents and the faculty.

Analysis of a COVID-19 Prescreening Process in an Outpatient Clinic at a University Hospital during the COVID-19 Pandemic

Background@#To minimize nosocomial infection against coronavirus disease 2019 (COVID-19), most hospitals conduct a prescreening process to evaluate the patient or guardian of any symptoms suggestive of COVID-19 or exposure to a COVID-19 patient at entrances of hospital buildings. In our hospital, we have implemented a two-level prescreening process in the outpatient clinic: an initial prescreening process at the entrance of the outpatient clinic (PPEO) and a second prescreening process is repeated in each department. If any symptoms or epidemiological history are identified at the second level, an emergency code is announced through the hospital's address system. The patient is then guided outside through a designated aisle. In this study, we analyze the cases missed in the PPEO that caused the emergency code to be applied. @*Methods@#All cases reported from March 2020 to April 2021 were analyzed retrospectively. We calculated the incidence of cases missed by the PPEO per 1,000 outpatients and compared the incidence between first-time hospital visitors and those visiting for the second time or more; morning and afternoon office hours; and days of the week. @*Results@#During the study period, the emergency code was applied to 449 cases missed by the PPEO. Among those cases, 20.7% were reported in otorhinolaryngology, followed by 11.6% in gastroenterology, 5.8% in urology, and 5.8% in dermatology. Fever was the most common symptom (59.9%), followed by cough (19.8%). The incidence of cases per 1,000 outpatients was significantly higher among first-time visitors than among those visiting for the second time or more (1.77 [confidence interval (CI), 1.44–2.10] vs. 0.59 [CI, 0.52–0.65], respectively) (P < 0.001). @*Conclusion@#Fever was the most common symptom missed by the PPEO, and otorhinolaryngology and gastroenterology most frequently reported missed cases. Cases missed by the PPEO were more likely to occur among first-time visitors than returning visitors. The results obtained from this study can provide insights or recommendations to other healthcare facilities in operating prescreening processes during the COVID-19 pandemic.

Prevention of infection from contrast agents

Until now, automatic contrast agent injector syringes licensed for consecutive one-time use have been employed with a number of patients. In 2016, regulation of automatic injector syringes ensured their single use, and reuse was strictly limited by law. However, this regulation creates the social problems of rising medical costs and resource waste. Many doctors are not significantly concerned about infection from contrast agent injection because the needle and connection lines on the patient side are set up for single use, the connections between syringes and contrast agents are reusable, and there are no reports of excessive infection. However, infection can nevertheless occur with injection of contrast agents. We should therefore implement the correct and safe use of contrast agents and take precautions against infection. To prevent infection due to contrast agents, syringes and connection lines for injection of such agents should be used once per patient, or multi-use licensed products should be used. In the latter case, reverse flow prevention filters must be used on the patient's side.

Prevention of infection from contrast agents

Until now, automatic contrast agent injector syringes licensed for consecutive one-time use have been employed with a number of patients. In 2016, regulation of automatic injector syringes ensured their single use, and reuse was strictly limited by law. However, this regulation creates the social problems of rising medical costs and resource waste. Many doctors are not significantly concerned about infection from contrast agent injection because the needle and connection lines on the patient side are set up for single use, the connections between syringes and contrast agents are reusable, and there are no reports of excessive infection. However, infection can nevertheless occur with injection of contrast agents. We should therefore implement the correct and safe use of contrast agents and take precautions against infection. To prevent infection due to contrast agents, syringes and connection lines for injection of such agents should be used once per patient, or multi-use licensed products should be used. In the latter case, reverse flow prevention filters must be used on the patient's side.

Prevention of infection from contrast agents

Until now, automatic contrast agent injector syringes licensed for consecutive one-time use have been employed with a number of patients. In 2016, regulation of automatic injector syringes ensured their single use, and reuse was strictly limited by law. However, this regulation creates the social problems of rising medical costs and resource waste. Many doctors are not significantly concerned about infection from contrast agent injection because the needle and connection lines on the patient side are set up for single use, the connections between syringes and contrast agents are reusable, and there are no reports of excessive infection. However, infection can nevertheless occur with injection of contrast agents. We should therefore implement the correct and safe use of contrast agents and take precautions against infection. To prevent infection due to contrast agents, syringes and connection lines for injection of such agents should be used once per patient, or multi-use licensed products should be used. In the latter case, reverse flow prevention filters must be used on the patient's side.

Clinical interventions and speech outcomes for individuals with submucous cleft palate

Background@#This study aimed to identify the initial diagnostic characteristics and treatment status of children with submucous cleft palate (SMCP) and to examine the relationship between the timing of surgical correction and the degree of articulation and resonance improvement. @*Methods@#This retrospective study included 72 children diagnosed with SMCP between 2008 and 2016. The evaluation criteria were the age of the initial visit, total number of visits, age at the end of treatment, speech problems, resonance problems, and speech therapy. @*Results@#Children with SMCP first visited the hospital at an average age of 34.32 months, and speech problems were identified at an average age of 48.53 months. Out of 72 children, 46 underwent surgery at an average age of 49.74 months. Four of these children required secondary surgery at an average age of 83.5 months. Among the children who underwent surgery before 3 years of age, 70% exhibited articulation improvements, with mild-to-moderate hypernasality. Articulation improvements showed no statistically significant differences according to age at the time of surgery. However, children who underwent surgery before 4 years had a better hypernasality rating than those who underwent surgery after 4 years of age. @*Conclusions@#Children with SMCP tend to undergo delayed treatment because the anatomical symptoms in some children with SMCP are unclear, and surgical interventions are considered only after speech problems are clarified. Starting interventions as early as possible reduces the likelihood of receiving secondary surgery and speech therapy, while increasing expectations for positive speech function at the end.

Dynamic Contrast-Enhanced MRI of the Prostate: Can Auto-Generated Wash-in Color Map Be Useful in Detecting Focal Lesion Enhancement?

PURPOSE: To evaluate the usefulness of wash-in color map in detecting early enhancement of prostate focal lesion compared to whole dynamic contrast-enhanced MRI (DEC MRI) images. MATERIALS AND METHODS: This study engaged 50 prostate cancer patients who underwent multiparametric MRI and radical prostatectomy as subjects. An expert [R1] and a trainee [R2] independently evaluated early enhancement and recorded the time needed to review 1) a wash-in color map and 2) whole DCE MRI images. RESULTS: The review of whole DCE images by R1 showed fair agreement with color map by R1, whole images by R2, and color map by R2 (weighted kappa values = 0.59, 0.44, and 0.58, respectively). Both readers took a significantly shorter time to review the color maps as compared to whole images (P < 0.001). CONCLUSION: A trainee could achieve better agreement with an expert when using wash-in color maps than when using whole DCE MRI images. Also, color maps took a significantly shorter evaluation time than whole images.

Korean Clinical Imaging Guidelines for Diagnosis of Headache Based on the 2017 Evidence-Based Clinical Imaging Guidelines

Headache is the most common cause of neurological disorders. The usefulness of imaging tests may vary depending on the patient's clinical situation. The Korean Society of Radiology and National Evidence-Based Healthcare Collaborating Agency have decided to develop evidence-based guidelines for the imaging tests necessary for diagnosing patients with selected, frequently encountered types of headache. Development, working, and advisory committees were formed. Recommendation statements were derived from the adaptive development methods provided by the existing guidelines. Non-contrast head CT is recommended in patients with acute thunderclap headache due to possible subarachnoid hemorrhage (SAH), and CT angiography is recommended to confirm aneurysmal SAH. In patients with non-acute headache and normal neurological findings, radiological examination is not recommended, but head MRI is recommended to investigate the cause of secondary headache. Non-contrast head MRI is recommended for new-onset headache with neurologic abnormalities in pregnant women.

Medical Institutions' Adherence to the PI-RADS v2 Minimum Technical Standards for Prostate MRI in Korea

PURPOSE@#To evaluate the adherence rate to Prostate Imaging-Reporting and Data System version 2 (PI-RADS v2) minimum technical standards of prostate magnetic resonance imaging (MRI) in Korean medical institutions.@*MATERIALS AND METHODS@#This study included 103 prostate MRI examinations from 85 outside medical institutions performed from March 2015 to January 2018. The difference in adherence rate to minimal technical standards of PI-RADS v2 was compared using a Fisher's exact test between subgroups divided by the magnetic strength of MRI machine, type of medical institution and presence of genitourinary radiologist.@*RESULTS@#Diffusion-weighted imaging (DWI) was obtained frequently in examinations performed in a 3-T machine, in university hospitals and in medical institutions where genitourinary radiologist work in than the others (p < 0.001, p < 0.001, p = 0.003). Many minimum technical standards of PI-RADS v2 showed significantly lower adherence rate in a 1.5-T machine, in a non-university hospital and in a medical institution without genitourinary radiologist than the others.@*CONCLUSION@#The frequency of obtaining DWI and the adherent rate to some of the PI-RADS v2 minimum technical standards were significantly higher in 3-T machines, university hospitals and medical institutions with a genitourinary radiologist.

Predictive Value of Interim and End-of-Therapy 18F-FDG PET/CT in Patients with Follicular Lymphoma / 대한핵의학회잡지

PURPOSE@#¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is the standard imaging modality for response evaluation in FDG-avid lymphoma, but the prognostic value is not established in follicular lymphoma (FL). This study investigated the prognostic value of Deauville 5-point scale (D5PS) from paired interim PET/CT (PET(Interim)) and end-of-induction therapy PET/CT (PET(EOI)) in patients with FL.@*METHODS@#FL staging and response assessment PET/CT images from 2013 to 2015 were retrospectively reviewed. PET(Interim) was performed 3 or 4 cycles after chemotherapy and PET(EOI) after 6 or 8 cycles. D5PS scores of 1, 2, and 3 were considered as negative (−), and scores 4 and 5 were considered as positive (+). Statistical analysis was done using Cox regression analysis, Kaplan-Meier survival analysis, and the log-rank test.@*RESULTS@#Thirty-three patients with set of baseline, interim, and end-of-induction therapy PET/CTstudies were included. Ten patients (30.3%) had progression. The median progression-free survival (PFS) was 38.8 months (range 3.5–72.7 months). On PET(Interim), 23 patients were negative and 10 were positive. On PET(EOI) scans, 29 patients were negative, and 4 were positive. On multivariate analysis, PET(EOI)(−) was associated with longer PFS. PET(Interim)(+) and PET(EOI)(+) patients had a significantly shorter PFS than PET(Interim)(−) patients (39.9 months, 95%confidence interval [CI] 23.0–56.9, versus 55.5months, 95%CI 49.7–61.2, p=0.005) and PET(EOI)(−) patients (14.2 months, 95% CI 8.5–19.8, versus 60.5 months, 95% CI 52.1–69.0, p<0.001).@*CONCLUSION@#For patients with FL, PET(Interim) and PET(EOI) response is predictive of PFS, and PET(EOI)(+) is an independent prognostic factor for progression of FL.

Predictive Value of Interim and End-of-Therapy 18F-FDG PET/CT in Patients with Follicular Lymphoma / 대한핵의학회잡지

PURPOSE: ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is the standard imaging modality for response evaluation in FDG-avid lymphoma, but the prognostic value is not established in follicular lymphoma (FL). This study investigated the prognostic value of Deauville 5-point scale (D5PS) from paired interim PET/CT (PET(Interim)) and end-of-induction therapy PET/CT (PET(EOI)) in patients with FL.METHODS: FL staging and response assessment PET/CT images from 2013 to 2015 were retrospectively reviewed. PET(Interim) was performed 3 or 4 cycles after chemotherapy and PET(EOI) after 6 or 8 cycles. D5PS scores of 1, 2, and 3 were considered as negative (−), and scores 4 and 5 were considered as positive (+). Statistical analysis was done using Cox regression analysis, Kaplan-Meier survival analysis, and the log-rank test.RESULTS: Thirty-three patients with set of baseline, interim, and end-of-induction therapy PET/CTstudies were included. Ten patients (30.3%) had progression. The median progression-free survival (PFS) was 38.8 months (range 3.5–72.7 months). On PET(Interim), 23 patients were negative and 10 were positive. On PET(EOI) scans, 29 patients were negative, and 4 were positive. On multivariate analysis, PET(EOI)(−) was associated with longer PFS. PET(Interim)(+) and PET(EOI)(+) patients had a significantly shorter PFS than PET(Interim)(−) patients (39.9 months, 95%confidence interval [CI] 23.0–56.9, versus 55.5months, 95%CI 49.7–61.2, p=0.005) and PET(EOI)(−) patients (14.2 months, 95% CI 8.5–19.8, versus 60.5 months, 95% CI 52.1–69.0, p<0.001).CONCLUSION: For patients with FL, PET(Interim) and PET(EOI) response is predictive of PFS, and PET(EOI)(+) is an independent prognostic factor for progression of FL.

Implementation of Korean Clinical Imaging Guidelines: A Mobile App-Based Decision Support System

OBJECTIVE: The aims of this study were to develop a mobile app-based clinical decision support system (CDSS) for implementation of Korean clinical imaging guidelines (K-CIGs) and to assess future developments therein. MATERIALS AND METHODS: K-CIGs were implemented in the form of a web-based application (http://cdss.or.kr/). The app containing K-CIGs consists of 53 information databases, including 10 medical subspecialties and 119 guidelines, developed by the Korean Society of Radiology (KSR) between 2015 and 2017. An email survey consisting of 18 questions on the implementation of K-CIGs and the mobile app-based CDSS was distributed to 43 members of the guideline working group (expert members of the KSR and Korean Academy of Oral and Maxillofacial Radiology) and 23 members of the consultant group (clinical experts belonging to related medical societies) to gauge opinion on the future developmental direction of K-CIGs. RESULTS: The web-based mobile app can be downloaded from the Google Play Store. Detailed information on the grade of recommendation, evidence level, and radiation dose for each imaging modality in the K-CIGs can be accessed via the home page and side menus. In total, 32 of the 66 experts contacted completed the survey (response rate, 45%). Twenty-four of the 32 respondents were from the working group and eight were from the consulting group. Most (93.8%) of the respondents agreed on the need for ongoing development and implementation of K-CIGs. CONCLUSION: This study describes the mobile app-based CDSS designed for implementation of K-CIGs in Korea. The results will allow physicians to have easy access to the K-CIGs and encourage appropriate use of imaging modalities.

Principles for evaluating the clinical implementation of novel digital healthcare devices

With growing interest in novel digital healthcare devices, such as artificial intelligence (AI) software for medical diagnosis and prediction, and their potential impacts on healthcare, discussions have taken place regarding the regulatory approval, coverage, and clinical implementation of these devices. Despite their potential, ‘digital exceptionalism’ (i.e., skipping the rigorous clinical validation of such digital tools) is creating significant concerns for patients and healthcare stakeholders. This white paper presents the positions of the Korean Society of Radiology, a leader in medical imaging and digital medicine, on the clinical validation, regulatory approval, coverage decisions, and clinical implementation of novel digital healthcare devices, especially AI software for medical diagnosis and prediction, and explains the scientific principles underlying those positions. Mere regulatory approval by the Food and Drug Administration of Korea, the United States, or other countries should be distinguished from coverage decisions and widespread clinical implementation, as regulatory approval only indicates that a digital tool is allowed for use in patients, not that the device is beneficial or recommended for patient care. Coverage or widespread clinical adoption of AI software tools should require a thorough clinical validation of safety, high accuracy proven by robust external validation, documented benefits for patient outcomes, and cost-effectiveness. The Korean Society of Radiology puts patients first when considering novel digital healthcare tools, and as an impartial professional organization that follows scientific principles and evidence, strives to provide correct information to the public, make reasonable policy suggestions, and build collaborative partnerships with industry and government for the good of our patients.

Status of Interchange of Medical Imaging in Korea: A Questionnaire Survey of Physicians

The purpose of this study was to summarize the results of a survey for physicians with specialties other than radiology about imaging studies of patients referred from other institutions. The survey was promoted through individual contacts or social network service and physicians who voluntarily responded to the survey were the subjects of the study. The questionnaire consisted of 11 questions about basic information and referrals about medical imaging. A total of 160 physicians from 30 specialties participated in the survey and 95.6% of the respondents worked in tertiary care center or general hospital. Patients were frequently referred with outside medical images. The most frequently referred imaging modalities were computed tomography and magnetic resonance imaging. However, radiological reports from outside institutions were rarely referred. Most physicians thought that reinterpretation for outside imaging is necessary to acquire a secondary opinion. In conclusion, considering that outside radiological reports are frequently missing and there are high demands on reinterpretation for outside imaging, guidelines for referral of radiological reports with medical imaging, basic elements of radiological reports, and reinterpretation need to be developed.

Suggested Protocol for Efficient Medical Image Information Exchange in Korea: Breast MRI

PURPOSE@#Establishment of an appropriate protocol for breast magnetic resonance imaging (MRI) in the study of image quality standards to enhance the effectiveness of medical image information exchange, which is part of the construction and activation of clinical information exchange for healthcare informatization.@*MATERIALS AND METHODS@#The recommended protocols of breast and MRI scans were reviewed and the questionnaire was prepared by a responsible researcher. Then, a panel of 9 breast dedicated radiologists was set up in Korea. The expert panel conducted a total of three Delphi agreements to draw up a consensus on the breast MRI protocol.@*RESULTS@#The agreed breast MRI recommendation protocol is a 1.5 Tesla or higher device that acquires images with prone position using a breast dedicated coil and includes T2-weighted and pre-contrast T1-weighted images. Contrast enhancement images are acquired at least two times, and include 60–120 seconds between images and after 4 minutes. The contrast enhancement T1-weighted image should be less than 3 mm in thickness, less than 120 seconds in temporal resolution, and less than 1.5 mm² in-plane pixel resolution.@*CONCLUSION@#The Delphi agreement of the domestic breast imaging specialist group has established the recommendation protocol of the effective breast MRI.

Principles for evaluating the clinical implementation of novel digital healthcare devices

With growing interest in novel digital healthcare devices, such as artificial intelligence (AI) software for medical diagnosis and prediction, and their potential impacts on healthcare, discussions have taken place regarding the regulatory approval, coverage, and clinical implementation of these devices. Despite their potential, ‘digital exceptionalism’ (i.e., skipping the rigorous clinical validation of such digital tools) is creating significant concerns for patients and healthcare stakeholders. This white paper presents the positions of the Korean Society of Radiology, a leader in medical imaging and digital medicine, on the clinical validation, regulatory approval, coverage decisions, and clinical implementation of novel digital healthcare devices, especially AI software for medical diagnosis and prediction, and explains the scientific principles underlying those positions. Mere regulatory approval by the Food and Drug Administration of Korea, the United States, or other countries should be distinguished from coverage decisions and widespread clinical implementation, as regulatory approval only indicates that a digital tool is allowed for use in patients, not that the device is beneficial or recommended for patient care. Coverage or widespread clinical adoption of AI software tools should require a thorough clinical validation of safety, high accuracy proven by robust external validation, documented benefits for patient outcomes, and cost-effectiveness. The Korean Society of Radiology puts patients first when considering novel digital healthcare tools, and as an impartial professional organization that follows scientific principles and evidence, strives to provide correct information to the public, make reasonable policy suggestions, and build collaborative partnerships with industry and government for the good of our patients.

Multiparametric MRI of Prostate Cancer after Biopsy: Little Impact of Hemorrhage on Tumor Staging

PURPOSE: To evaluate differences in staging accuracy of prostate cancer according to the extent of hemorrhage on multiparametric MRI performed after biopsy. MATERIALS AND METHODS: We enrolled 71 consecutive patients with biopsy-proven prostate cancer. Patients underwent MRI followed by a prostatectomy at our institution in 2014. Two radiologists reviewed the MRI to determine the tumor stage. Correlation between biopsy-MRI interval and extent of hemorrhage was evaluated. Regression analyses were used to determine factors associated with accuracy of tumor staging. RESULTS: The mean interval between biopsy and MRI was 17.4 ± 10.2 days (range, 0–73 days). The interval between prostate biopsy and MRI and the extent of hemorrhage were not significantly correlated (P = 0.880). There was no significant difference in the accuracy rate of staging between the small and large hemorrhage groups. CONCLUSION: Biopsy-induced hemorrhage in the prostate gland is not sufficiently absorbed over time. The extent of hemorrhage and the short interval between biopsy and MRI may not impair tumor detection or staging on multiparametric MRI.

The Imaging Features of Desmoid Tumors: the Usefulness of Diffusion Weighted Imaging to Differentiate between Desmoid and Malignant Soft Tissue Tumors

PURPOSE: To evaluate the imaging findings of desmoid tumors using various imaging modalities and to evaluate whether diffusion-weighted imaging (DWI) can help differentiate between desmoid and malignant tumors. MATERIALS AND METHODS: The study included 27 patients with pathologically confirmed desmoid tumors. Two radiologists reviewed 23 computed tomography (CT), 12 magnetic resonance imaging (MRI) and 8 positron emission tomography-computed tomography (PET-CT) scans of desmoid tumors and recorded data regarding the shape, multiplicity, size, location, degree of enhancement, and presence or absence of calcification or hemorrhage. The signal intensity of masses on T1- and T2-weighted imaging and the presence or absence of whirling or band-like low signal intensity on T2-weighted imaging were recorded. The apparent diffusion coefficient (ADC) values of the desmoid tumors in nine patients with DWIs were compared with the ADC values of 32 malignant tumors. The maximum standardized uptake value (SUV(max)) on PET-CT images was measured in 8 patients who underwent a PET-CT. RESULTS: The mean size of the 27 tumors was 6.77 cm (range, 2.5-26 cm) and four tumors exhibited multiplicity. The desmoid tumors were classified by shape as either mass forming (n = 18), infiltrative (n = 4), or combined (n = 5). The location of the tumors was either intra-abdominal (n = 15), within the abdominal wall (n = 8) or extra-abdominal (n = 4). Among the 27 tumors, 21 showed moderate to marked enhancement and 22 showed homogeneous enhancement. Two tumors showed calcifications and one displayed hemorrhage. Eleven of the 12 MR T2-weighted images showed whirling or band-like low signal intensity areas in the mass. The mean ADC value of the desmoid tumors (1493 × 10⁻⁶ mm²/s) was significantly higher than the mean of the malignant soft tissue tumors (873 × 10⁻⁶ mm²/s, P < 0.001). On the PET-CT images, all tumors exhibited an intermediate SUV(max) (mean, 3.7; range, 2.3–4.5). CONCLUSION: Desmoids tumors showed homogenous, moderate to marked enhancement on CT and MRI scans and a characteristic whirling or band-like pattern on T2-weighted images. DWI can be useful for the differentiation of desmoid tumors from malignant soft tissue tumors.