Artificial intelligence-based polyp size measurement in gastrointestinal endoscopy using the auxiliary waterjet as a reference.

BACKGROUND: Measurement of colorectal polyp size during endoscopy is mainly performed visually. In this work, we propose a novel polyp size measurement system (Poseidon) based on artificial intelligence (AI) using the auxiliary waterjet as a measurement reference. METHODS: Visual estimation, biopsy forceps-based estimation, and Poseidon were compared using a computed tomography colonography-based silicone model with 28 polyps of defined sizes. Four experienced gastroenterologists estimated polyp sizes visually and with biopsy forceps. Furthermore, the gastroenterologists recorded images of each polyp with the waterjet in proximity for the application of Poseidon. Additionally, Poseidon's measurements of 29 colorectal polyps during routine clinical practice were compared with visual estimates. RESULTS: In the silicone model, visual estimation had the largest median percentage error of 25.1 % (95 %CI 19.1 %-30.4 %), followed by biopsy forceps-based estimation: median 20.0 % (95 %CI 14.4 %-25.6 %). Poseidon gave a significantly lower median percentage error of 7.4 % (95 %CI 5.0 %-9.4 %) compared with other methods. During routine colonoscopies, Poseidon presented a significantly lower median percentage error (7.7 %, 95 %CI 6.1 %-9.3 %) than visual estimation (22.1 %, 95 %CI 15.1 %-26.9 %). CONCLUSION: In this work, we present a novel AI-based method for measuring colorectal polyp size with significantly higher accuracy than other common sizing methods.

FDG PET correlates weakly with HIF-1α expression in solid tumors: a meta-analysis.

BACKGROUND: Hypoxia-inducible factor (HIF)-1α plays a key role in hypoxic adaptation of tumor cells. Overexpression of HIF-1α is associated with tumor aggressiveness and worse prognosis in several malignancies. Presumably, expression of HIF-1a may be reflected by positron emission tomography with 2-deoxy-2 [fluorine-18] fluoro-D-glucose (18F-FDG PET). There are inconsistent data about relationships between FDG PET and HIF-1α. PURPOSE: To provide evident data about associations between maximum standardized uptake value (SUVmax) and HIF-1α expression in solid tumors. MATERIAL AND METHODS: MEDLINE, SCOPUS, and EMBASE databases were screened for relationships between SUV and HIF-1α up to August 2019. Overall, 21 studies with 1154 patients were identified. The following data were extracted from the literature: authors; year of publication; number of patients; and correlation coefficients. RESULTS: Correlation coefficients between SUVmax and HIF-1α were in the range of -0.51-0.71. The pooled correlation coefficient was 0.27 (95% confidence interval [CI] = 0.14-0.41). Furthermore, correlation coefficients for some tumor entities were calculated. For this sub-analysis, data for primary tumors with >2 reports were included. The calculated correlation coefficients in the analyzed subgroups were as follows: head and neck squamous cell carcinoma: ρ = 0.25 (95% CI = 0.07-0.42); non-small lung cell cancer: ρ = 0.27 (95% CI = -0.14-0.67); uterine cervical cancer: ρ = -0.09 (95% CI = -0.89-0.71); thymic tumors: ρ = 0.39 (95% CI = 0.04-0.58). CONCLUSION: SUVmax of FDG PET correlated weakly with expression of HIF-1α both in overall sample and tumor subgroups. Therefore, FDG PET cannot be used for prediction of hypoxia in clinical practice.

Liver Iron Content Determination Using a Volumetric Breath-Hold Gradient-Echo Sequence With In-Line R2 * Calculation.

BACKGROUND: Liver iron overload is a serious condition occurring in patients requiring blood transfusions (eg, in thalassemia and different forms of anemia) or with dysfunctional iron resorption, since there is no physiological mechanism to excrete iron. Above a certain level of iron concentration, chelation therapy is indicated. To monitor therapy success, liver iron content should be assessed regularly. A noninvasive method is important for patient management. Existing MRI methods suffer from long acquisition times and cost. PURPOSE: To study the correlation of liver iron content (LIC) reference values to liver R2 * determined using a 3D breath-hold multigradient echo (GRE) MRI sequence, employing accelerated acquisition by parallel imaging and in-line R2 * calculation. STUDY TYPE: Prospective. POPULATION: In all, 117 patients (22.1 ± 14.1 years, 66 men) suspected of iron overload. SEQUENCE: GRE. FIELD STRENGTH: 1.5T. ASSESSMENT: For comparison, a regulatory-approved method with a considerably longer scan time was used, providing LIC reference values. Participants were divided into a calibration group (65 participants), analyzed independently by two observers, and a validation group (52 participants). STATISTICAL TESTS: Linear correlation parameters were evaluated for R2 * values with LIC reference values, and for LIC determined from R2 * for validation group participants with LIC reference values. Sensitivity/specificity for clinical relevant LIC thresholds were analyzed. Interobserver variability was determined by intraclass correlation coefficient (ICC). RESULTS: Interobserver agreement was excellent, with an ICC of 0.99, P < 0.001. Good correlation (R2 = 0.89) and congruence of LIC values obtained with our method to LIC reference values was found, and almost identical diagnostic accuracy. Sensitivity/specificity were 0.98/0.67 for the diagnostic relevant LIC threshold of 4.5 mg/g and 1.0/0.95 for the threshold of 7 mg/g. DATA CONCLUSION: MRI acquisition times for determination of LIC can be significantly reduced by the use of comprehensive in-line R2 * map generation without compromising diagnostic accuracy. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

Improvement of image quality applying iterative scatter correction for grid-less skeletal radiography in trauma room setting.

BACKGROUND: Iterative reconstruction is well established for CT. Plain radiography also takes advantage of iterative algorithms to reduce scatter radiation and improve image quality. First applications have been described for bedside chest X-ray. A recent experimental approach also provided proof of principle for skeletal imaging. PURPOSE: To examine clinical applicability of iterative scatter correction for skeletal imaging in the trauma setting. MATERIAL AND METHODS: In this retrospective single-center study, 209 grid-less radiographs were routinely acquired in the trauma room for 12 months, with imaging of the chest (n = 31), knee (n = 111), pelvis (n = 14), shoulder (n = 24), and other regions close to the trunk (n = 29). Radiographs were postprocessed with iterative scatter correction, doubling the number of images. The radiographs were then independently evaluated by three radiologists and three surgeons. A five-step rating scale and visual grading characteristics analysis were used. The area under the VGC curve (AUCVGC) quantified differences in image quality. RESULTS: Images with iterative scatter correction were generally rated significantly better (AUCVGC = 0.59, P < 0.01). This included both radiologists (AUCVGC = 0.61, P < 0.01) and surgeons (AUCVGC = 0.56, P < 0.01). The image-improving effect was significant for all body regions; in detail: chest (AUCVGC = 0.64, P < 0.01), knee (AUCVGC = 0.61, P < 0.01), pelvis (AUCVGC = 0.60, P = 0.01), shoulder (AUCVGC = 0.59, P = 0.02), and others close to the trunk (AUCVGC = 0.59, P < 0.01). CONCLUSION: Iterative scatter correction improves the image quality of grid-less skeletal radiography in the clinical setting for a wide range of body regions. Therefore, iterative scatter correction may be the future method of choice for free exposure imaging when an anti-scatter grid is omitted due to high risk of tube-detector misalignment.

Frequency and Diagnostic Implications of Image Artifacts by Eye-Lens Shielding in Head CT.

OBJECTIVE: The eye lens is one of the most radiosensitive organs, and medical radiation is one of the main causes of cataracts. To protect the lens during head CT examinations, protectors have been developed; however, they can lead to image artifacts, which is a major disadvantage of their use. This study retrospectively evaluates the frequency and extent of artifacts caused by these protectors related to three anatomic regions (eye, brain, and bone) and their dependence on protector positioning. MATERIALS AND METHODS: Datasets from 261 consecutive head CT examinations obtained during 3.5 months of routine clinical imaging were assessed. Diagnostic quality of the images was evaluated by objective measuring and subjective scoring on a 5-point Likert scale. Furthermore, the position of the lens protector in correlation to the eye lens and the intensity and frequency of artifacts were analyzed. RESULTS: Only 4.6% of all analyzed examinations were completely free from artifacts; 95.4% showed artifacts at least in the orbital cavity. Although the brain was affected in 27.8% of cases, in only 5.8% of cases was there a risk of misinterpretation, such as suspected intracranial bleeding. In 24.9% of cases, the lens was not properly covered by the protector. A too cranial position of the protector was identified as the main risk factor for cerebral artifacts. CONCLUSION: Eye shielding for brain CT examinations often leads to artifacts. However, in only a small percentage of cases do these artifacts affect tissue depiction in regions beyond the eye (i.e., brain or bones). Correct positioning is mandatory to minimize artifacts.

Iterative scatter correction for grid-less skeletal radiography allows improved image quality equal to an antiscatter grid in adjunct with dose reduction: a visual grading study of 20 body donors.

BACKGROUND: Iterative scatter correction (ISC) is a new technique applicable to plain radiography; comparable to iterative reconstruction for computed tomography, it promises dose reduction and image quality improvement. ISC for bedside chest X-rays has been applied and evaluated for some time and has recently been commercially offered for plain skeletal radiography. PURPOSE: To analyze the potential of ISC for plain skeletal radiography with regard to image quality improvement, dose reduction, and replacement for an antiscatter grid. MATERIAL AND METHODS: A total of 385 radiographs with different imaging protocols of the pelvis and cervical spine were acquired from 20 body donors. Radiographs were rated by four radiologists. Ratings were analyzed with visual grading characteristics (VGC) analysis. The area under the VGC curve was used as a measure of difference in image quality. RESULTS: Without ISC, the grid-less images were rated significantly worse than their grid-based counterparts (0.389, P = 0.005); adding ISC made image quality equal (0.498; P = 0.963). In grid-less imaging, reduction of dose by 50% led to significant image quality impairment (0.415, P = 0.001); this was fully counterbalanced when ISC was added (0.512; P = 0.588). CONCLUSION: ISC for plain skeletal radiography has the ability to replace the antiscatter grid without image quality impairment, to improve image quality in grid-less imaging, and to reduce patient radiation dose by 50% without substantial loss in image quality.

Diagnostic value of MRI-based 3D texture analysis for tissue characterisation and discrimination of low-grade chondrosarcoma from enchondroma: a pilot study.

OBJECTIVES: To explore the diagnostic value of MRI-based 3D texture analysis to identify texture features that can be used for discrimination of low-grade chondrosarcoma from enchondroma. METHODS: Eleven patients with low-grade chondrosarcoma and 11 patients with enchondroma were retrospectively evaluated. Texture analysis was performed using mint Lesion: Kurtosis, entropy, skewness, mean of positive pixels (MPP) and uniformity of positive pixel distribution (UPP) were obtained in four MRI sequences and correlated with histopathology. The Mann-Whitney U-test and receiver operating characteristic (ROC) analysis were performed to identify most discriminative texture features. Sensitivity, specificity, accuracy and optimal cut-off values were calculated. RESULTS: Significant differences were found in four of 20 texture parameters with regard to the different MRI sequences (p<0.01). The area under the ROC curve values to discriminate chondrosarcoma from enchondroma were 0.876 and 0.826 for kurtosis and skewness in contrast-enhanced T1 (ceT1w), respectively; in non-contrast T1, values were 0.851 and 0.822 for entropy and UPP, respectively. The highest discriminatory power had kurtosis in ceT1w with a cut-off ≥3.15 to identify low-grade chondrosarcoma (82 % sensitivity, 91 % specificity, accuracy 86 %). CONCLUSION: MRI-based 3D texture analysis might be able to discriminate low-grade chondrosarcoma from enchondroma by a variety of texture parameters. KEY POINTS: • MRI texture analysis may assist in differentiating low-grade chondrosarcoma from enchondroma. • Kurtosis in the contrast-enhanced T1w has the highest power of discrimination. • Tools provide insight into tumour characterisation as a non-invasive imaging biomarker.

Quantification of inflammatory activity in patients with Crohn's disease using diffusion weighted imaging (DWI) in MR enteroclysis and MR enterography.

Background Individual studies have demonstrated the potential of diffusion-weighted magnetic resonance imaging (DWI-MRI) for identifying inflamed bowel segments. However, these studies were conducted with rather small patient cohorts and in most cases by means of MR enterography only. Purpose To demonstrate the feasibility of detecting inflamed bowel segments in a large collective of patients with Crohn's disease using DWI in MR enteroclysis and MR enterography and to compare the results of both techniques, also considering clinical parameters by means of the Harvey-Bradshaw Index (HBI). Material and Methods Ninety-six patients underwent MRI enteroclysis and 35 patients MR enterography, both with additional DWI. The HBI as well as apparent diffusion coefficients (ADC) in areas of inflamed and normal bowel wall were determined. Thus resulting in 208 bowel segments that were visualized and subsequently statistically analyzed. Results There were no significant differences in ADC values in MR enteroclysis and MR enterography ( P = 0.383 in inflammation, P = 0.223 in normal wall). Areas of inflammation showed statistically highly significant lower ADC values than areas of normal bowel wall ( P < 0.001). An ADC threshold of 1.56 × 10-3 mm2/s can distinguish between normal and inflamed bowel segments with a sensitivity of 97.4% and a specificity of 99.2%. A highly significant correlation could be shown between ADC and HBI values ( P = 0.001). Conclusion DWI-MRI facilitates recognition of inflamed bowel segments in patients with Crohn's disease and the ADC values show an excellent correlation to the HBI. There were no significant differences in ADC values in MR enteroclysis and MR enterography. An ADC threshold of 1.56 × 10-3 mm2/s differentiates between normal and inflamed bowel wall.

Oral distension methods for small bowel MRI: comparison of different agents to optimize bowel distension.

Background Different methods for bowel distension prior to magnetic resonance imaging (MRI) examinations were described in recent years. Purpose To compare orally administered psyllium or locust bean gum / mannitol (LBM) with tylose administered through a duodenal catheter for bowel distension in patients undergoing MRI examination of the small bowel. Material and Methods Three different methods of bowel distension prior to MRI were compared: tylose applied through a duodenal catheter and orally administered psyllium and LBM in three groups with 15 patients each. Datasets were blinded and reviewed independently by two experienced radiologists, who assessed the diagnostic value and the maximum luminal diameter. Results Tylose was superior to psyllium and LBM in the examination of the duodenum and proximal jejunum. LBM was superior to the other methods for distension of the ileum and terminal ileum. The greatest luminal diameter of the duodenum was achieved after tylose and distension of the terminal ileum was the best in patients receiving LBM. The psyllium group was inferior to the other two groups in all segments. Conclusion By using LBM as an oral method of bowel distension, many patients can avoid the unpleasant placement of a duodenal catheter without compromising the diagnostic value of the examination.

Pictorial Review on Imaging Findings in Cerebral CTP in Patients with Acute Stroke and Its Mimics: A Primer for General Radiologists.

The imaging evaluation of computed tomography (CT), CT angiography (CTA), and CT perfusion (CTP) is of crucial importance in the setting of each emergency department for suspected cerebrovascular impairment. A fast and clear assignment of characteristic imaging findings of acute stroke and its differential diagnoses is essential for every radiologist. Different entities can mimic clinical signs of an acute stroke, thus the knowledge and fast identification of stroke mimics is important. A fast and clear assignment is necessary for a correct diagnosis and a rapid initiation of appropriate therapy. This pictorial review describes the most common imaging findings in CTP with clinical signs for acute stroke or other acute neurological disorders. The knowledge of these pictograms is therefore essential and should also be addressed in training and further education of radiologists.

Radiomics and Clinicopathological Characteristics for Predicting Lymph Node Metastasis in Testicular Cancer.

Accurate prediction of lymph node metastasis (LNM) in patients with testicular cancer is highly relevant for treatment decision-making and prognostic evaluation. Our study aimed to develop and validate clinical radiomics models for individual preoperative prediction of LNM in patients with testicular cancer. We enrolled 91 patients with clinicopathologically confirmed early-stage testicular cancer, with disease confined to the testes. We included five significant clinical risk factors (age, preoperative serum tumour markers AFP and B-HCG, histotype and BMI) to build the clinical model. After segmenting 273 retroperitoneal lymph nodes, we then combined the clinical risk factors and lymph node radiomics features to establish combined predictive models using Random Forest (RF), Light Gradient Boosting Machine (LGBM), Support Vector Machine Classifier (SVC), and K-Nearest Neighbours (KNN). Model performance was assessed by the area under the receiver operating characteristic (ROC) curve (AUC). Finally, the decision curve analysis (DCA) was used to evaluate the clinical usefulness. The Random Forest combined clinical lymph node radiomics model with the highest AUC of 0.95 (±0.03 SD; 95% CI) was considered the candidate model with decision curve analysis, demonstrating its usefulness for preoperative prediction in the clinical setting. Our study has identified reliable and predictive machine learning techniques for predicting lymph node metastasis in early-stage testicular cancer. Identifying the most effective machine learning approaches for predictive analysis based on radiomics integrating clinical risk factors can expand the applicability of radiomics in precision oncology and cancer treatment.

Gastroenteropancreatic Neuroendocrine Tumors-Current Status and Advances in Diagnostic Imaging.

Gastroenteropancreatic neuroendocrine neoplasia (GEP-NEN) is a heterogeneous and complex group of tumors that are often difficult to classify due to their heterogeneity and varying locations. As standard radiological methods, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET/CT) are available for both localization and staging of NEN. Nuclear medical imaging methods with somatostatin analogs are of great importance since radioactively labeled receptor ligands make tumors visible with high sensitivity. CT and MRI have high detection rates for GEP-NEN and have been further improved by developments such as diffusion-weighted imaging. However, nuclear medical imaging methods are superior in detection, especially in gastrointestinal NEN. It is important for radiologists to be familiar with NEN, as it can occur ubiquitously in the abdomen and should be identified as such. Since GEP-NEN is predominantly hypervascularized, a biphasic examination technique is mandatory for contrast-enhanced cross-sectional imaging. PET/CT with somatostatin analogs should be used as the subsequent method.

Diagnostic, Structured Classification and Therapeutic Approach in Cystic Pancreatic Lesions: Systematic Findings with Regard to the European Guidelines.

Due to the increasing use of cross-sectional imaging techniques and new technical possibilities, the number of incidentally detected cystic lesions of the pancreas is rapidly increasing in everyday radiological routines. Precise and rapid classification, including targeted therapeutic considerations, is of essential importance. The new European guideline should also support this. This review article provides information on the spectrum of cystic pancreatic lesions, their appearance, and a comparison of morphologic and histologic characteristics. This is done in the context of current literature and clinical value. The recommendations of the European guidelines include statements on conservative management as well as relative and absolute indications for surgery in cystic lesions of the pancreas. The guidelines suggest surgical resection for mucinous cystic neoplasm (MCN) ≥ 40 mm; furthermore, for symptomatic MCN or imaging signs of malignancy, this is recommended independent of its size (grade IB recommendation). For main duct IPMNs (intraductal papillary mucinous neoplasms), surgical therapy is always recommended; for branch duct IPMNs, a number of different risk criteria are applicable to evaluate absolute or relative indications for surgery. Based on imaging characteristics of the most common cystic pancreatic lesions, a precise diagnostic classification of the tumor, as well as guidance for further treatment, is possible through radiology.

Quantitative Evaluation of COVID-19 Pneumonia CT Using AI Analysis-Feasibility and Differentiation from Other Common Pneumonia Forms.

PURPOSE: To implement the technical feasibility of an AI-based software prototype optimized for the detection of COVID-19 pneumonia in CT datasets of the lung and the differentiation between other etiologies of pneumonia. METHODS: This single-center retrospective case-control-study consecutively yielded 144 patients (58 female, mean age 57.72 ± 18.25 y) with CT datasets of the lung. Subgroups including confirmed bacterial (n = 24, 16.6%), viral (n = 52, 36.1%), or fungal (n = 25, 16.6%) pneumonia and (n = 43, 30.7%) patients without detected pneumonia (comparison group) were evaluated using the AI-based Pneumonia Analysis prototype. Scoring (extent, etiology) was compared to reader assessment. RESULTS: The software achieved an optimal sensitivity of 80.8% with a specificity of 50% for the detection of COVID-19; however, the human radiologist achieved optimal sensitivity of 80.8% and a specificity of 97.2%. The mean postprocessing time was 7.61 ± 4.22 min. The use of a contrast agent did not influence the results of the software (p = 0.81). The mean evaluated COVID-19 probability is 0.80 ± 0.36 significantly higher in COVID-19 patients than in patients with fungal pneumonia (p < 0.05) and bacterial pneumonia (p < 0.001). The mean percentage of opacity (PO) and percentage of high opacity (PHO ≥ -200 HU) were significantly higher in COVID-19 patients than in healthy patients. However, the total mean HU in COVID-19 patients was -679.57 ± 112.72, which is significantly higher than in the healthy control group (p < 0.001). CONCLUSION: The detection and quantification of pneumonia beyond the primarily trained COVID-19 datasets is possible and shows comparable results for COVID-19 pneumonia to an experienced reader. The advantages are the fast, automated segmentation and quantification of the pneumonia foci.

The cisterna chyli: prevalence, characteristics and predisposing factors.

The purpose of this study was to determine the prevalence and characteristics of the cisterna chyli (CC) in a large 3,000-patient cohort and to identify potential predisposing factors for the development of a CC. Three thousand consecutive contrast-enhanced CT examinations (1,261 women, 1,739 men, mean age 61.0 years) of the chest and/or abdomen were included in this retrospective study. Imaging characteristics of the CC (size, attenuation, location) were documented as well as clinical information (malignant disease, pattern of metastasis). A CC was found in 16.1% of the patients with an average volume of 302 microl. The mean attenuation was 4.8 Hounsfield units (HU). Twenty percent of the CC showed CT densities of 15 HU and higher. Patients with malignancies showed a significantly (p < 0.001) higher prevalence of CC (340/1,757, 19.4%) than patients with benign conditions (144/1,243, 11.6%). Especially the finding of a large CC (>1,000 microl) represents an elevated relative risk for malignancy of 1.7 (p = 0.0017). We found a significant association between malignant disease and the presence and size of a cisterna chyli. Identifying the continuity between the CC and the thoracic duct is a safer method to distinguish a CC from retrocrural lymph nodes than near-water CT attenuation alone.

Determination of reference values for the soluble transferrin receptor (sTfR) on a cross sectional population sample.

BACKGROUND: Aim of the study was to determine reference values for the soluble Transferrin Receptor (sTfR) in a cross sectional population sample. METHODS: For the determination of reference values, using a standard calibrated fluorescence-immunoassay, the samples (990 females; 1060 males; 13 - 65 years old) were divided into five groups according to age and sex. Soluble transferrin receptor and ferritin were measured by a fluorescence-immunoassay with AIA-21 (TOSOH BIOSCIENCE, Tessenderlo, Belgium). The sTfR/logFer-Index was calculated by dividing the sTfR by the logarithm of ferritin, the logsTfR/Fer-Index by dividing the logarithm of sTfR by ferritin. RESULTS: Mean sTfR concentration was 1.75 +/- 0.39 mg/l in group I (13-17 years), 1.65 +/- 0.34 mg/l in group II (18-30 years), 1.60 +/- 0.39 mg/l in group III (31-40 years), 1.54 +/- 0.39 mg/l in group IV (41-50 years), and 1.59 +/- 0.34 mg/l in group V (51-65 years), respectively. A gender-specific difference between the groups was observed: sTfR concentrations were lower in group I (p < 0.005) and group II (p = 0.01) for women. The mean sTfR-concentration decreased consecutively in the age group I-IV (13-50 years). CONCLUSIONS: This is the first cross sectional population based study to determine reference values for sTfR-concentrations. Our results demonstrated age- and gender-specific differences.

Evaluation of lung tumor perfusion by dynamic contrast-enhanced MRI.

The characterization of solid pulmonary lesions with imaging methods remains a diagnostic challenge. The aim of this study was to correlate kinetic parameters of dynamic perfusion magnetic resonance imaging (MRI) with histological tumor classification. Dynamic contrast-enhanced MRI of 31 patients with pulmonary masses (five benign lesions, 26 malignant tumors) was acquired in the tumor areas every 20 s for a mean duration of 124 s. Contrast uptake (CU) was measured by signal analysis in regions of interest (ROIs). The beginning and duration of CU, maximum CU (MCU, % of baseline), maximum contrast upslope (%/s) and the delay to the maximum contrast upslope (s) were calculated. All lesions were classified histologically. The beginning of CU correlated significantly with the MCU delay in all lesions (P=.033). The frequency of a plateau phase was higher in malignant tumors compared to benign lesions (P=.031). Masses with a high MCU showed more frequently a washout of contrast medium after a plateau phase (P=.006) and a higher maximum contrast upslope (P<.001). The MCU delay time was shorter in adenocarcinoma than in squamous cell carcinoma (P=.004). These results indicate that dynamic contrast enhanced MRI might become instrumental in differentiating benign from malignant intrapulmonary tumors and distinguishing adenocarcinoma from squamous cell carcinoma.