Imaging-detected bone stress injuries at the Tokyo 2020 summer Olympics: epidemiology, injury onset, and competition withdrawal rate.

BACKGROUND: Prevention and early detection of injuries are essential in optimising sport participation and performance. The aim of this study is to investigate the epidemiology, athlete injury history, and competition withdrawal rate of imaging-detected bone stress injuries during the Tokyo 2020 Olympic Games. METHODS: We collected and analysed imaging and clinical information in athletes with bone stress injuries diagnosed in the Olympic Village polyclinic during the Games. Two physicians independently and retrospectively reviewed all imaging examinations of bone stress injuries. RESULTS: A total of 11,315 individual athletes from 206 National Olympic Committees competed at the Games, during which 567 MRIs and 352 X-rays were performed at the Olympic Village polyclinic. Radiology examinations revealed four stress fractures and 38 stress reactions in 29 athletes (median age 24 years, range 18-35 years). Of these, 72% of athletes (n = 21) had symptoms before entering the Olympic Village. Bone stress injuries were most common in women (55%), the lower extremities (66%), and track and field athletes (45%). Six athletes (21%) did not start or did not finish their competitions. CONCLUSIONS: This study revealed 42 imaging-detected bone stress injuries in the polyclinic of the Tokyo 2020 Olympic Village. The high proportion of athletes with symptoms before entering the village and the high proportion of competition withdrawals suggests the usefulness of an early MRI examination.

Epidemiology of MRI-detected muscle injury in athletes participating in the Tokyo 2020 Olympic Games.

OBJECTIVE: Muscle injury is one of the most common injuries occurring at the Olympic Games often with devastating consequences. Epidemiological injury surveillance is recognised by the IOC as essential for injury prevention and management. We aimed to describe the incidence, anatomical location and classification of MRI-detected muscle injuries in athletes who participated in the Tokyo 2020 Olympic Games. METHODS: Two board-certified orthopaedic surgeons, highly experienced in reviewing MRIs, independently and retrospectively reviewed all MRIs collected at the Tokyo 2020 Olympic Games from clinical reports generated by board-certified musculoskeletal radiologists at the IOC Polyclinic. The presence and anatomical site of muscle injuries were classified as: type a: myofascial/peripheral; type b: muscle belly or musculotendinous junction; and type c: injury which extends into the tendon, with reference to the British Athletics Muscle Injury Classification. RESULTS: Fifty-nine MRI-detected muscle injuries were seen in 40 male and 19 female athletes. 24 athletes (41%) were unable to fully compete in their event. Fifty-two injuries (88%) involved lower extremity muscles with hamstring muscle injuries most common (32 of 59, 54%). Half of all muscle injuries occurred in athletes participating in athletics (30 of 59, 51%). 21 athletes (35%) sustained type a injuries, 14 athletes (24%) type b injuries and 24 athletes (41%) type c injuries. Of athletes with type c injuries, 18 (75%) did not complete their competition, a rate significantly higher than types a and b (OR 14.50, 95% CI 4.0 to 51.9, p<0.001). CONCLUSION: For athletes sustaining muscle injuries during the Olympic Games, our study demonstrates the prognostic relevance of muscle injury anatomical site and severity for predicting completion or non-completion of an Olympic athlete's competition.

Uterine Cervical Carcinoma: Evaluation Using Non-Gaussian Diffusion Kurtosis Imaging and Its Correlation With Histopathological Findings.

OBJECTIVE: The aim of the study was to assess non-Gaussian diffusion kurtosis imaging (DKI)'s usefulness as a noninvasive method to evaluate tumor invasion depth, histological grade, and lymph node metastasis in cervical carcinoma (CC) patients. METHODS: Twenty-two consecutive patients with histologically confirmed CC were examined by 1.5-T MRI and non-Gaussian DKI with 4 b values of 0, 500, 1000, and 2000 s/mm2. Kurtosis (K), diffusivity (D), and apparent diffusion coefficient (ADC) maps were compared with histopathological findings. RESULTS: Kurtosis maps revealed the fibrous stroma as a distinct high K zone (1.442 ± 0.373) that was significantly different from values of the cervical mucosa, outer stroma, and parametrium (0.648 ± 0.083, 0.715 ± 0.113, and 0.504 ± 0.060, respectively, P < 0.0001). Kurtosis (1.189 ± 0.228) and D (0.961 ± 0.198 × 10-3 mm2/s) values of all CCs were significantly different from those of all uterine cervical wall layers. Kurtosis and D values were significantly correlated with histological grades of CCs (r = 0.934, P < 0.0001, and r = -0.925, P < 0.0001, respectively), whereas no significant differences were found in ADC values between grades 2 and 3 CCs (P = 0.787). Metastatic and nonmetastatic lymph nodes showed significantly different K (P < 0.0001) and D (P < 0.0001) values; however, their ADC values did not show significant differences (P = 0.437). For differentiating grade 3 CCs from grade 1 or 2 CCs, the areas under the curve for K (0.991, P = 0.0375) and D (0.982, P = 0.0337) values were significantly higher than those for ADC values (0.759). For differentiating metastatic and nonmetastatic lymph nodes, the areas under the curve for K (0.974, P = 0.0028) and D (0.968, P = 0.0018) values were significantly higher than those for ADC (0.596). CONCLUSIONS: Non-Gaussian DKI may be clinically useful for noninvasive evaluation of tumor invasion depth, histological grade, and lymph node metastasis in CC patients.

Diffusion-Tensor Imaging of Uterine Cervical Carcinoma: Correlation With Histopathologic Findings.

The authors investigated the usefulness of diffusion-tensor imaging (DTI) for evaluating tumor invasion depth, histologic grade, and lymph node metastasis in patients with cervical carcinoma (CC). Fifteen consecutive patients with histologically confirmed CC underwent 1.5-T magnetic resonance imaging and DTI. The CCs were clearly depicted as hypointense areas on all DTI maps. Fractional anisotropy, mean diffusivity, and axial diffusivity showed significantly inverse correlations with CC histologic grades and were significantly different between metastatic and nonmetastatic lymph nodes.

Endometrial carcinoma: Evaluation using diffusion-tensor imaging and its correlation with histopathologic findings.

BACKGROUND: Although the prognosis of endometrial carcinoma (EMC) patients strictly depends on tumor invasion depth and its histologic grade, accurate preoperative assessment of these prognostic factors is often difficult. PURPOSE: To determine the usefulness of diffusion-tensor imaging (DTI) as a noninvasive method for evaluating tumor invasion depth and its histologic grade in patients with EMC. STUDY TYPE: Prospective. POPULATION: Twenty-five consecutive patients with histologically confirmed EMC who were surgically treated at our institution. FIELD STRENGTH/SEQUENCE: DTI was performed with a 1.5T MRI system using a single-shot echo-planar imaging sequence with b values of 0 and 1000 s/mm2 and motion-probing gradients in nine noncollinear directions. ASSESSMENT: Fractional anisotropy (FA), mean diffusivity (MD), and axial diffusivity (AD) maps were analyzed by three observers and compared with histopathologic findings. STATISTICAL TESTS: Dunnett's test, Spearman's rank correlation coefficient, and receiver operating characteristic (ROC) curve analyses. RESULTS: FA maps from all patients distinctly identified the junctional zone as a high-FA zone (0.864 ± 0.037) that was significantly different from the endometrium and outer myometrium (0.251 ± 0.030 and 0.471 ± 0.091, respectively; P < 0.001). All EMCs were clearly depicted as hypointense areas on all DTI maps. AD maps provided the best tumor-to-uterus contrast, and EMCs (0.977 ± 0.120 × 10-3 mm2 /s) had significantly lower AD values than all other layers of the normal uterine wall (2.166 ± 0.408, 2.010 ± 0.289, and 2.655 ± 0.203 × 10-3 mm2 /s, respectively; P < 0.001). EMCs were clearly demarcated from the normal uterine wall, and DTI maps and histopathologic data yielded identical findings regarding tumor invasion depth. FA values showed a significant inverse correlation (r = -0.818; P < 0.001) with histologic grades 1, 2, and 3 of endometrioid adenocarcinomas. DATA CONCLUSION: In patients with EMC, DTI may be useful for evaluating tumor invasion depth and its histologic grade. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:250-260.

Value of a Computer-aided Detection System Based on Chest Tomosynthesis Imaging for the Detection of Pulmonary Nodules.

Purpose To assess the value of a computer-aided detection (CAD) system for the detection of pulmonary nodules on chest tomosynthesis images. Materials and Methods Fifty patients with and 50 without pulmonary nodules underwent both chest tomosynthesis and multidetector computed tomography (CT) on the same day. Fifteen observers (five interns and residents, five chest radiologists, and five abdominal radiologists) independently evaluated tomosynthesis images of 100 patients for the presence of pulmonary nodules in a blinded and randomized manner, first without CAD, then with the inclusion of CAD marks. Multidetector CT images served as the reference standard. Free-response receiver operating characteristic analysis was used for the statistical analysis. Results The pooled diagnostic performance of 15 observers was significantly better with CAD than without CAD (figure of merit [FOM], 0.74 vs 0.71, respectively; P = .02). The average true-positive fraction and false-positive rate per all cases with CAD were 0.56 and 0.26, respectively, whereas those without CAD were 0.47 and 0.20, respectively. Subanalysis showed that the diagnostic performance of interns and residents was significantly better with CAD than without CAD (FOM, 0.70 vs 0.62, respectively; P = .001), whereas for chest radiologists and abdominal radiologists, the FOM with CAD values were greater but not significantly: 0.80 versus 0.78 (P = .38) and 0.74 versus 0.73 (P = .65), respectively. Conclusion CAD significantly improved diagnostic performance in the detection of pulmonary nodules on chest tomosynthesis images for interns and residents, but provided minimal benefit for chest radiologists and abdominal radiologists. © RSNA, 2017 Online supplemental material is available for this article.

Colorectal carcinoma: Ex vivo evaluation using q-space imaging; Correlation with histopathologic findings.

BACKGROUND: Although the prognosis of colorectal carcinoma (CRC) patients depends on the histologic grade (HG) and lymph node metastasis (LNM), accurate preoperative assessment of these prognostic factors is often difficult. PURPOSE: To assess the HG and extent of LNM by q-space imaging (QSI) for preoperative diagnosis of CRC. STUDY TYPE: Prospective. SPECIMEN: A total of 20 colorectal tissue samples containing adenocarcinomas and resected lymph nodes (LNs). FIELD STRENGTH/SEQUENCE: QSI was performed with a 3T MRI system using a diffusion-weighted echo-planar imaging sequence: repetition time, 10,000 msec; echo time, 216 or 210 msec; field of view, 113 × 73.45 mm; matrix, 120 × 78; section thickness, 4 mm; and 11 b values ranging from 0 to 9000 s/mm2 . ASSESSMENT: The mean displacement (MDP; µm), zero-displacement probability (ZDP; arbitrary unit [a.u.]), kurtosis (K; a.u.), and apparent diffusion coefficient (ADC) were analyzed by two observers and compared with histopathologic findings. STATISTICAL TESTS: Spearman's rank correlation coefficient, Mann-Whitney U-test, and ROC curve analyses. RESULTS: For all 20 carcinomas, the MDP, ZDP, K, and ADC were 8.87 ± 0.37 µm, 82.0 ± 6.2 a.u., 74.3 ± 3.0 a.u., and 0.219 ± 0.040 × 10-3 mm2 /s, respectively. The MDP (r = -0.768; P < 0.001), ZDP (r = 0.768; P < 0.001), and K (r = 0.785; P < 0.001) were significantly correlated with the HG of CRC, but not the ADC (r = 0.088; P = 0.712). There were also significant differences in the MDP, ZDP, and K between metastatic and nonmetastatic LNs (all, P < 0.001), but not the ADC (P = 0.082). In the HG of CRC and LNM, the area under the curve was significantly greater for MDP, ZDP, and K than for ADC. DATA CONCLUSION: QSI provides useful diagnostic information to assess the HG and extent of LNM in CRC. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1059-1068.

Accuracy of CT Colonography for Detection of Polypoid and Nonpolypoid Neoplasia by Gastroenterologists and Radiologists: A Nationwide Multicenter Study in Japan.

OBJECTIVES: The objective of this study was to assess prospectively the diagnostic accuracy of computer-assisted computed tomographic colonography (CTC) in the detection of polypoid (pedunculated or sessile) and nonpolypoid neoplasms and compare the accuracy between gastroenterologists and radiologists. METHODS: This nationwide multicenter prospective controlled trial recruited 1,257 participants with average or high risk of colorectal cancer at 14 Japanese institutions. Participants had CTC and colonoscopy on the same day. CTC images were interpreted independently by trained gastroenterologists and radiologists. The main outcome was the accuracy of CTC in the detection of neoplasms ≥6 mm in diameter, with colonoscopy results as the reference standard. Detection sensitivities of polypoid vs. nonpolypoid lesions were also evaluated. RESULTS: Of the 1,257 participants, 1,177 were included in the final analysis: 42 (3.6%) were at average risk of colorectal cancer, 456 (38.7%) were at elevated risk, and 679 (57.7%) had recent positive immunochemical fecal occult blood tests. The overall per-participant sensitivity, specificity, and positive and negative predictive values for neoplasms ≥6 mm in diameter were 0.90, 0.93, 0.83, and 0.96, respectively, among gastroenterologists and 0.86, 0.90, 0.76, and 0.95 among radiologists (P<0.05 for gastroenterologists vs. radiologists). The sensitivity and specificity for neoplasms ≥10 mm in diameter were 0.93 and 0.99 among gastroenterologists and 0.91 and 0.98 among radiologists (not significant for gastroenterologists vs. radiologists). The CTC interpretation time by radiologists was shorter than that by gastroenterologists (9.97 vs. 15.8 min, P<0.05). Sensitivities for pedunculated and sessile lesions exceeded those for flat elevated lesions ≥10 mm in diameter in both groups (gastroenterologists 0.95, 0.92, and 0.68; radiologists: 0.94, 0.87, and 0.61; P<0.05 for polypoid vs. nonpolypoid), although not significant (P>0.05) for gastroenterologists vs. radiologists. CONCLUSIONS: CTC interpretation by gastroenterologists and radiologists was accurate for detection of polypoid neoplasms, but less so for nonpolypoid neoplasms. Gastroenterologists had a higher accuracy in the detection of neoplasms ≥6 mm than did radiologists, although their interpretation time was longer than that of radiologists.

Optimization of left adrenal vein sampling in primary aldosteronism: Coping with asymmetrical cortisol secretion.

We evaluated the influence of catheter sampling position and size on left adrenal venous sampling (AVS) in patients with primary aldosteronism (PA) and analyzed their relationship to cortisol secretion. This retrospective study included 111 patients with a diagnosis of primary aldosteronism who underwent tetracosactide-stimulated AVS. Left AVS was obtained from two catheter positions - the central adrenal vein (CAV) and the common trunk. For common trunk sampling, 5-French catheters were used in 51 patients, and microcatheters were used in 60 patients. Autonomous cortisol secretion was evaluated with a low-dose dexamethasone suppression test in 87 patients. The adrenal/inferior vena cava cortisol concentration ratio [selectivity index (SI)] was significantly lower in samples from the left common trunk than those of the left CAV and right adrenal veins, but this difference was reduced when a microcatheter was used for common trunk sampling. Sample dilution in the common trunk of the left adrenal vein can be decreased by limiting sampling speed with the use of a microcatheter. Meanwhile, there was no significant difference in SI between the left CAV and right adrenal veins. Laterality, determined according to aldosterone/cortisol ratio (A/C ratio) based criteria, showed good reproducibility regardless of sampling position, unlike the absolute aldosterone value based criteria. However, in 11 cases with autonomous cortisol co-secretion, the cortisol hypersecreting side tended to be underestimated when using A/C ratio based criteria. Left CAV sampling enables symmetrical sampling, and may be essential when using absolute aldosterone value based criteria in cases where symmetrical cortisol secretion is uncertain.

Predicting Retear after Repair of Full-Thickness Rotator Cuff Tear: Two-Point Dixon MR Imaging Quantification of Fatty Muscle Degeneration-Initial Experience with 1-year Follow-up.

Purpose To determine the degree of preoperative fatty degeneration within muscles, postoperative longitudinal changes in fatty degeneration, and differences in fatty degeneration between patients with full-thickness supraspinatus tears who do and those who do not experience a retear after surgery. Materials and Methods This prospective study had institutional review board approval and was conducted in accordance with the Committee for Human Research. Informed consent was obtained. Fifty patients with full-thickness supraspinatus tears (18 men, 32 women; mean age, 67.0 years ± 8.0; age range, 41-91 years) were recruited. The degrees of preoperative and postoperative fatty degeneration were quantified by using a two-point Dixon magnetic resonance (MR) imaging sequence; two radiologists measured the mean signal intensity on in-phase [S(In)] and fat [S(Fat)] images. Estimates of fatty degeneration were calculated with "fat fraction" values by using the formula S(Fat)/S(In) within the supraspinatus, infraspinatus, and subscapularis muscles at baseline preoperative and at postoperative 1-year follow-up MR imaging. Preoperative fat fractions in the failed-repair group and the intact-repair group were compared by using the Mann-Whitney U test. Results The preoperative fat fractions in the supraspinatus muscle were significantly higher in the failed-repair group than in the intact-repair group (37.0% vs 19.5%, P < .001). Fatty degeneration of the supraspinatus muscle tended to progress at 1 year postoperatively in only the failed-repair group. Conclusion MR imaging quantification of preoperative fat fractions by using a two-point Dixon sequence within the rotator cuff muscles may be a viable method for predicting postoperative retear. (©) RSNA, 2016.

Hepatocellular Carcinoma Histological Grade Prediction: A Quantitative Comparison of Diffusion-Weighted, T2-Weighted, and Hepatobiliary-Phase Magnetic Resonance Imaging.

OBJECTIVES: This study aimed to compare quantitative assessments for predicting hepatocellular carcinoma (HCC) histological grades using magnetic resonance imaging. METHODS: We retrospectively reviewed magnetic resonance imaging data from 49 patients with 54 surgically resected HCCs (11 well differentiated, 29 moderately differentiated, and 14 poorly differentiated). We measured the lesion-to-liver relative contrast ratio (RCR) on diffusion-weighted (DW), T2-weighted (T2W), and ethoxybenzyl-hepatobiliary images. We also evaluated contrast-to-noise ratio (CNR) on DW images, and the apparent diffusion coefficient. We compared the feasibility of these parameters in predicting HCC histological grade. RESULTS: Areas under the receiver operating characteristic curves of both the DW RCR (97%) and DW CNR (97%) were significantly greater compared with those of the apparent diffusion coefficient (79%), T2W RCR (81%), and ethoxybenzyl-hepatobiliary RCR (80%) (P < 0.05, 0.001, and 0.001, respectively). CONCLUSIONS: The DW RCR and DW CNR might represent accurate predictors of HCC histological grade.

Cervical ultrasound and computed tomography of Kawasaki disease: Comparison with lymphadenitis.

BACKGROUND: Differentiating Kawasaki disease (KD) from cervical lymphadenitis (CL) is clinically difficult but essential given that treatment and outcome differ significantly. Research on differentiation between KD and CL using ultrasound (US) and computed tomography (CT) is limited. The purpose of this study was to identify cervical US and CT findings that may differentiate KD from CL. METHODS: We retrospectively reviewed cervical US of 25 KD patients and 25 CL patients, and CT of 14 KD patients, and 14 CL patients. Two radiologists analyzed specific imaging features on US (lymph node size, shape, echogenicity, margins, laterality, necrosis, and presence of normal hilum) and on CT (size and location of enlarged nodes, laterality, perinodal infiltration, and retropharyngeal edema). RESULTS: On US, patients with KD more frequently had lymph nodes with a "cluster of grapes" appearance (KD vs CL: 64% vs 32%, P < 0.05) and less frequently had poorly circumscribed margins (0% vs 36%, P < 0.01), necrosis (0% vs 32%, P < 0.01), or non-visualization of the hilum (4% vs 36%, P < 0.01). On CT, KD patients more frequently had retropharyngeal edema (100% vs 29%, P < 0.001) and less frequently had level 4 lymphadenopathy (14% vs 79%, P < 0.01) than CL patients. CONCLUSIONS: Ultrasound is mainly useful for excluding purulent lymphadenopathy while CT is a useful diagnostic tool for differentiating KD from CL, especially in patients with incomplete KD, who present with prominent cervical lymphadenopathy and other equivocal principal findings.

Quantification of Fatty Degeneration Within the Supraspinatus Muscle by Using a 2-Point Dixon Method on 3-T MRI.

OBJECTIVE: The objective of this study was to quantify fatty degeneration of the supraspinatus muscle by using a 2-point Dixon technique on 3-T MRI and to evaluate the correlation of muscular atrophy and fat fraction values among different severities of rotator cuff tears across differing ages and sexes. SUBJECTS AND METHODS: Patients with shoulder pain (n = 359) were evaluated by shoulder MRI on a 3-T unit, including a 2-point Dixon sequence for quantification of muscle atrophy and fatty degeneration within the supraspinatus muscle. Two board-certified musculoskeletal radiologists evaluated the degree of rotator cuff tears in three groups: full-thickness tear (n = 63), partial tear (n = 54), and no tear (n = 242). In quantitative analysis, we measured signal intensity values of in-phase images (SIn) and fat images (SFat) within the supraspinatus muscle, and the fat fraction was calculated as SFat/SIn. The Thomazeau occupation ratio was used as a quantitative index of muscular atrophy. Fat fraction and muscle atrophy were evaluated among these groups. RESULTS: Fat fraction values were changed with the degree of rotator cuff tears and were (mean ± SD) 0.258 ± 0.123 among patients with full-thickness tears, 0.166 ± 0.067 among patients with partial tears, and 0.128 ± 0.061 among patients with no tears, with statistically significant differences (p < 0.001). The values were higher in female than in male patients in all groups. The Pearson correlation coefficient was 0.348 between age and fat fraction value, and 0.664 between muscular atrophy rate and fat fraction value. CONCLUSION: An increase in supraspinatus fatty degeneration was statistically significantly correlated with severity of supraspinatus tears and moderately correlated with muscular atrophy. Fatty degeneration tends to progress more rapidly than muscular atrophy in female patients, with statistically significant sex differences.

MRI findings of the shoulder and hip joint in patients with polymyalgia rheumatica.

OBJECTIVES: The purpose of this study is to evaluate magnetic resonance imaging (MRI) findings of the shoulder and hip joint in patients with polymyalgia rheumatica (PMR). METHODS: MR images of a total of 25 PMR patients (23 shoulders and 6 hips), 43 rheumatoid arthritis (RA) patients (22 shoulders and 22 hips), and 50 control patients (25 shoulders and 25 hips) were examined. The following MRI findings were evaluated: In the shoulder, thickness and abnormalities of the supraspinatus tendon, effusion around the glenohumeral joint, subacromial-subdeltoid bursa, and the biceps tendon; In the hip, effusion around the acetabulofemoral joint, iliopsoas bursa, and trochanteric bursa. Periarticular soft-tissue edema and bone findings were also analyzed. RESULTS: The supraspinatus tendon was significantly thicker in PMR patients than in RA patients and control patients (p < 0.05). Severe rotator cuff tendinopathy was frequently observed in PMR patients (p = 0.002). The scores for the amount of effusions (joint, bursa, and tendon sheath in the shoulder and bursa in the hip) were much higher in PMR patients (p < 0.05). Periarticular soft tissue edema was detected more frequently in PMR patients than in RA patients and control patients (p < 0.05). CONCLUSIONS: Thick supraspinatus tendon, severe rotator cuff tendinopathy, effusion around the joints, and periarticular soft tissue edema can be good indicators for the diagnosis of PMR.

CT findings of gastric and intestinal anisakiasis.

PURPOSE: To illustrate the CT findings of gastrointestinal anisakiasis. SUBJECTS AND METHODS: The Institutional Review Board approving this retrospective study waived the requirement for informed consent. Review of our emergency department's clinical records from September 2008 to January 2012 identified 41 consecutive patients who were diagnosed with gastrointestinal anisakiasis. 20 patients were diagnosed with gastric anisakiasis with endoscopically proven Anisakis larvae, and 21 patients were diagnosed with intestinal anisakiasis with positive test results for anti-anisakidae antibody and the presence of intestinal lesions on CT. Two radiologists retrospectively assessed the CT findings. RESULTS: The mean time delay from raw fish ingestion to symptom onset was 5.2 h (range 0.5-24 h) in gastric anisakiasis and 39 h (range 12-120 h) in intestinal anisakiasis. Gastric anisakiasis showed marked submucosal edema of the gastric wall (20/20 patients, 100%), increased attenuation of adjacent fat (19/20, 95%), and ascites (14/20, 70%) on CT. Intestinal anisakiasis showed marked submucosal edema of the intestine (21/21 patients, 100%) without showing complete intraluminal occlusion, ascites (21/21, 100%), increased attenuation of adjacent fat (19/21, 90%), and fluid collection in the distal segment of the constricted small intestine (13/21, 62%) on CT. CONCLUSION: Severe submucosal edema with ascites is a characteristic finding of gastrointestinal anisakiasis when compared with other forms of gastroenteritis. When CT shows the typical findings of gastrointestinal anisakiasis, radiologists may suggest the possibility of clinically undiagnosed anisakiasis, especially in intestinal anisakiasis as the diagnosis is sometimes difficult due to the long interval between food intake and symptom onset.

Human papillomavirus-associated plantar epidermoid cysts: MR and US imaging appearance.

Epidermoid cysts are epithelial cysts that present as slow-growing intradermal or subcutaneous lesions. While recent epidemiological studies have isolated human papillomavirus (HPV) from plantar epidermoid cysts, imaging findings in HPV-associated epidermoid cysts have not been previously reported. We describe imaging findings in two patients with HPV-associated plantar epidermoid cysts. Magnetic resonance (MR) imaging and ultrasonography (US) showed linear arrangement of several adjacent globular cysts. This appearance is hypothesized to result from HPV-associated eccrine duct metaplasia leading to cyst formation and later traumatic rupture leading to formation of multiple adjacent cystic components. It may be useful to suggest assessing the presence of HPV antigen in plantar lesions having these imaging findings.

Contrast-enhanced MRI for detecting intravertebral cleft formation: relation to the time since onset of vertebral fracture.

OBJECTIVE: The purpose of this study was to investigate the advantages of contrast-enhanced MRI (CE-MRI) for detecting intravertebral clefts over unenhanced MRI in relation to the time since onset of vertebral fracture. MATERIALS AND METHODS: In this retrospective study, a total of 115 patients (88 women, 27 men; mean age, 77.1 years) who underwent percutaneous vertebroplasty for a single-level compression fracture within 7 days of preprocedural MRI were enrolled. Two radiologists evaluated preprocedural unenhanced MRI (T1-weighted and STIR) and CE-MRI examinations for intravertebral clefts on separate days by consensus. The time from the onset of fracture to MRI was classified into three groups: early phase fractures (< 1 month), late phase fractures (1-3 months), and chronic phase fractures (≥ 3 months). The cement distribution during percutaneous vertebroplasty was used as a reference standard, and detectability of clefts was compared between unenhanced MRI and CE-MRI in relation to the time frame. An analog of the McNemar test was used for analyses. RESULTS: There were 104 patients (90.4%) with and 11 patients (9.6%) without a cleft. The sensitivities of unenhanced MRI and CE-MRI, respectively, for detecting clefts were 60.9% and 91.3% for early phase fractures (p = 0.02); 78.6% and 100% for late phase fractures (p = 0.014); and 92.5% and 94.3% for chronic phase fractures (p = 0.3). The specificities were the same for both groups (100% for each time frame). CONCLUSION: CE-MRI is more sensitive than unenhanced MRI for detecting intravertebral clefts in patents with benign compression fractures less than 3 months old.

Syndromes associated with vascular tumors and malformations: a pictorial review.

Use of the International Society for the Study of Vascular Anomalies (ISSVA) classification system has been strongly recommended in recent years because of the need for separate therapeutic measures for patients with vascular tumors and malformations. In the ISSVA classification system, vascular tumors, which are neoplastic, are distinguished from vascular malformations, which are caused by vascular structural anomalies and are not neoplastic, on the basis of the presence or absence of neoplastic proliferation of vascular endothelial cells. It is important that radiologists be familiar with the development, diagnosis, and treatment of vascular tumors and malformations, especially the imaging features of low- and high-flow vascular malformations. Some vascular tumors and malformations develop in isolation, whereas others develop within the phenotype of a syndrome. Syndromes that are associated with vascular tumors include PHACE syndrome. Syndromes that are associated with vascular malformations include Sturge-Weber, Klippel-Trénaunay, Proteus, blue rubber bleb nevus, Maffucci, and Gorham-Stout syndromes, all of which demonstrate low flow, and Rendu-Osler-Weber, Cobb, Wyburn-Mason, and Parkes Weber syndromes, all of which demonstrate high flow. Because imaging findings may help identify such syndromes as systemic, it is important that radiologists familiarize themselves with these conditions.

Magnetic resonance imaging for extramammary Paget's disease: radiological and pathological correlations.

Extramammary Paget's disease (EMPD) is a rare cutaneous neoplasm that is thought to represent intraepithelial adenocarcinoma developing in an area rich in apocrine glands. Magnetic resonance imaging (MRI) findings for this disease are not well established. We report three cases of pathologically confirmed EMPD in which MRI was performed before surgery. The lesions were widespread in the epidermis and the dermis. Lesions were sharply well enhanced on gadolinium-enhanced T1-weighted imaging and appeared hyperintense on diffusion-weighted imaging in all cases. Areas with enhancement in depth corresponded well with the pathological lesion. In addition, different malignant legions were found on the same images from MRI in two cases, indicating potential associations with other malignancies. We describe the MRI findings and their pathological correlation. MRI could be useful for preoperative evaluation of disease spread and detection of associated malignancies.

Significance of size and location of appendicoliths as exacerbating factor of acute appendicitis.

The aim of the present study was to investigate the significance of appendicoliths as an exacerbating factor of acute appendicitis using multivariate analysis. A total of 254 patients with pathologically proved acute appendicitis were enrolled in this retrospective study (male, 51 %; mean age, 40.1 years; range, 15-91 years). Two radiologists performed a consensus evaluation of preoperative CT images for the presence of appendicoliths in consensus. When there were appendicoliths, they assessed the number and location of appendicoliths, and measured the longest diameter of the largest appendicolith. Pathological diagnosis was used for the reference standard. The relationships of appendicoliths to gangrenous appendicitis and to perforated appendicitis were each assessed with multiple logistic regression models, which were adjusted for demographic and clinical characteristics of patients. Significant relationships were identified between gangrenous appendicitis and the presence of appendicoliths (OR, 2.2; 95 % CI, 1.2-4.0), the largest appendicolith more than 5 mm in the longest (OR, 3.0; 95 % CI, 1.6-5.7), and location of an appendicolith at the root of the appendix (OR, 2.0; 95 % CI, 1.1-3.8). Among the CT characteristics, the location of an appendicolith at the root of the appendix only showed significant relationship with perforated appendicitis (OR, 4.5; 95 % CI, 1.4-15.4). Size of the largest appendicolith and location of appendicoliths at the root of the appendix are exacerbating factors of acute appendicitis.