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Purpose To investigate the clinical practices of diagnosing multicystic cervical lesions as a means to develop a more appropriate diagnostic algorithm for gastric-type adenocarcinoma (GAS) and its precursors. Methods Clinical information for 159 surgically treated patients for multicystic disease of the uterine cervix was collected from 15 hospitals. We performed a central review of the MRI and pathological findings. The MRI findings were categorized into four types including two newly proposed imaging features based on the morphology and distribution of cysts, and the diagnosis accuracy was assessed. Among the four MRI types, types 1 and 2 were categorized as benign lesions that included LEGH; type 3 were precancerous lesions (with an assumption of atypical LEGH); and type 4 were malignant lesions. Results The central pathological review identified 56 cases of LEGH, seven with GAS, four with another form of carcinoma, and 92 with benign disease. In clinical practice, over-diagnosis of malignancy (suspicion of MDA) occurred for 12/19 cases (63.2%) and under-diagnosis of malignancy occurred for 4/11 (36%). Among the 118 patients who had a preoperative MRI and underwent a hysterectomy, type 3 or 4 MRI findings in conjunction with abnormal cytology were positively indicative of premalignancy or malignancy, with a sensitivity and specificity of 61.1% and 96.7%, respectively. Conclusions Although the correct preoperative diagnosis of cervical cancer with a multicystic lesion is challenging, the combination of cytology and MRI findings creates a more appropriate diagnostic algorithm that significantly improves the diagnostic accuracy for differentiating benign disease from premalignancy and malignancy.

Borderline epithelial ovarian tumors are a distinct pathologic entity characterized by increased epithelial proliferation and nuclear atypia, but without frank stromal invasion. Borderline tumor (BT) is now considered to represent an intermediate phase in the stepwise progression from benign to malignant ovarian epithelial tumor. Since BTs commonly manifest at early stages in women of reproductive age and are associated with a good prognosis, making the correct diagnosis is important in determining whether a patient is a candidate for fertility-sparing surgery. There are six histologic BT subtypes (serous, mucinous, seromucinous, endometrioid, clear cell, and Brenner), and each has different MRI features, reflecting their unique histologic architectures. Radiologists should be aware of the MRI features that can suggest BTs. These features include a hyperintense papillary architecture with hypointense internal branching, which can be observed with serous and seromucinous BTs on T2-weighted images; aggregates of microcysts that have hypointensity on T2-weighted images and reticular enhancement on contrast-enhanced T2-weighted images, which can be seen with mucinous BTs; and moderately high signal intensity on diffusion-weighted images along with relatively high apparent diffusion coefficient values, which can be observed regardless of the histologic subtype. Nevertheless, because the imaging features of BTs overlap with those of many benign lesions (eg, cystadenoma and cystadenofibroma, decidualized endometriosis, and polypoid endometriosis) and malignant tumors (ovarian cancers and metastases), histologic confirmation is required for the final diagnosis. Special emphasis is placed on the MRI features of BTs, pathologic correlation, and the challenges related to diagnosis.

Objectives To investigate neuroendocrine carcinoma (NEC) of the uterine cervix cases for MRI features and staging, as well as pathological correlations and survival. Results FIGO was I in 42, II in 14, III in 1, and IV in 5 patients. T2-weighted MRI showed homogeneous slightly high signal intensity and obvious restricted diffusion (ADC map, low intensity; DWI, high intensity) throughout the tumor in most cases, and mild enhancement in two-thirds. In 50 patients who underwent a radical hysterectomy and lymphadenectomy without neoadjuvant chemotherapy (NAC), intrapelvic T staging by MRI overall accuracy was 88.0% with reference to pathology staging, while patient-based sensitivity, specificity, and accuracy for metastatic pelvic lymph node detection was 38.5%, 100%, and 83.3%, respectively. During a mean follow-up period of 45.6 months (range 4.3-151.0 months), 28 patients (45.2%) experienced recurrence and 24 (38.7%) died. Three-year progression-free and overall survival rates for FIGO I, II, III, and IV were 64.3% and 80.9%, 50% and 64.3%, 0% and 0%, and 0% and 0%, respectively. Materials and methods Sixty-two patients with histologically surgery-proven uterine cervical NEC were enrolled. Twelve received NAC. Clinical data, pathological findings, and pretreatment pelvic MRI findings were retrospectively reviewed. Thirty-two tumors were pure NEC and 30 mixed with other histotypes. The NECs were small cell type (41), large cell type (18), or a mixture of both (3). Conclusions Homogeneous lesion texture with obvious restricted diffusion throughout the tumor are features suggestive of cervical NEC. Our findings show that MRI is reliable for T staging of cervical NEC.

Severe adverse drug reactions in response to intravascular contrast media used in computed tomography, although rare, are potentially life-threatening. This retrospective cohort study aimed to estimate the incidence rate of severe adverse drug reactions to nonionic contrast media at the National Hospital Organization Osaka National Hospital and to report individually on each fatality. In total, 42,501 relevant cases were obtained from the individual case safe reports of the Ministry of Health, Labour and Welfare and the reports of code blue from our hospital database for the period of January 2013 to December 2017. The cases were studied, and the rate of adverse drug reactions was calculated from these data. Severe adverse drug reactions occurred in 0.019% (8/42,501) of the patients, including two deaths. All eight of these patients presented with disturbance of consciousness. Additionally, one patient had dyspnea, five had distributive shock that recovered after treatment, and two died. However, a causal relationship to the contrast media could not be established in one death. When examining the medical histories, four patients were found to have renal dysfunction. Although the rate of severe adverse drug reactions in this study appears to be higher than expected, the sample size of 42,501 patients is insufficient to conclusively determine the incidence and mortality rates of adverse drug reactions, as these rates are extremely low. Further studies are required to estimate the countrywide prevalence of adverse drug reactions in response to contrast media.

This study aimed to assess the relationship between pancreatic fibrosis measured by the extracellular volume fraction (ECV) using contrast-enhanced computed tomography (CT) and the histologic pancreatic fibrosis fraction and investigate the relationship between pancreatic fibrosis and pancreatic cancer.The study included 88 consecutive patients (48 males, 40 females; median age, 69 years; range, 17-89 years); 47 had pancreatic cancer, and 41 had other diseases. Fifty-two cases were evaluated pathologically for pancreatic fibrosis. The histologic pancreatic fibrosis fraction was quantified using image analysis software in nontumorous pancreatic tissue at the resection stump using 2-µm-thick Azan-stained slides. Two board-certified radiologists measured ECV in the pancreatic parenchyma at an estimated transection line. The correlation between histologic pancreatic fibrosis fraction and ECV was investigated, and whether the ECV value could be used as a biomarker for pancreatic cancer was investigated.The histologic pancreatic fibrosis fraction was significantly correlated with the ECV (r = 0.64, P 0.01). Pancreatic fibrosis evaluated by ECV was higher in pancreatic cancer patients than in other patients (P 0.01). On receiver-operating characteristic curve analysis, the ECV had good diagnostic accuracy for the development of pancreatic cancer (cut-off value 32.8%; sensitivity 61.0%, specificity 85.1%). ECV was identified on multivariate analysis as an independent risk factor for pancreatic cancer (odds ratio 1.16; P 0.01).Extracellular volume fraction was strongly related to the histologic pancreatic fibrosis fraction, which was independently associated with pancreatic cancer. Thus, extracellular volume fraction is an imaging biomarker that reflects the progression of pancreatic fibrosis and may potentially help predict the development of pancreatic cancer, although further investigation will be needed.

Background Endoscopic and transanal local resection without lymph node dissection are treatment options for patients with a low risk of lymph node metastasis; however, some patients might have undiagnosed lymph node metastases before surgery. This retrospective study aimed to evaluate the efficacy of preoperative PET/CT for diagnosing regional lymph node metastasis. Methods Patients who underwent curative resection with lymph node dissection for colorectal cancer at Osaka University between January 2012 and December 2015 were included. The cut-off values appropriate for diagnosing lymph node metastasis were calculated by way of a receiver operating characteristic (ROC) curves from maximum standard unit value (SUVmax) of main tumour, and lymph node short axis, and SUVmax of lymph node. The cut-off values of primary tumour SUVmax: 7, short-axis diameter of the lymph node at 7 mm, and lymph node SUVmax at 1.5 were set. Result A total of 541 patients were included. Regional lymph node metastases were confirmed in resected specimens from 187 patients (35 per cent). With a primary tumour SUVmax of 7 used as a cut-off value, the sensitivity and specificity of regional lymph node metastasis were 70.1 per cent and 45.5 per cent respectively. With a cut-off short-axis diameter of the regional lymph node of 7 mm, the sensitivity and specificity of regional lymph node metastasis were 75.2 per cent and 82.6 per cent respectively, and with a cut-off regional lymph node SUVmax of 1.5, the sensitivity and specificity of regional lymph node metastasis were 78.6 per cent and 96.8 per cent respectively. When the diagnostic criteria were defined by a lymph node short-axis diameter of 7 mm or SUVmax of 1.5, the sensitivity and specificity were 87.4 per cent and 81.8 per cent respectively. Conclusion Preoperative PET/CT is a useful modality for evaluating regional lymph node metastasis in patients with colorectal cancer.

This study aimed to evaluate the effects of deep learning (DL) reconstruction and a postprocessing sharpening filter on the image quality of single-shot fast spin-echo (SSFSE) T2-weighted imaging (T2WI) of the uterus.Fifty consecutive patients who underwent pelvic magnetic resonance imaging were included. Parasagittal T2WI with a slice thickness of 4 mm was obtained with the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) and SSFSE sequences (mean scan time, 204 and 22 seconds, respectively). The following 3 types of SSFSE images were reconstructed, and the signal-to-noise ratio (SNR) and tissue contrast were assessed: conventional reconstruction (SSFSE-C), DL reconstruction (SSFSE-DL), and DL with a sharpening filter (SSFSE-DLF). Three radiologists independently assessed image quality, and area under the visual grading characteristics curve (AUCVGC) analysis was performed to compare the SSFSE and PROPELLER images.Compared with that of the PROPELLER images, the SNR of the SSFSE-C, SSFSE-DL, and SSFSE-DLF images was significantly lower (P0.05), significantly higher (P0.05), and equivalent, respectively. The SSFSE-DL images exhibited significantly lower contrast between the junctional zone and myometrium than those obtained with the other sequences (P0.05). In qualitative comparisons with the PROPELLER images, all 3 SSFSE sequences, SSFSE-DL, and SSFSE-DLF demonstrated significantly higher scores for artifacts, noise, and sharpness, respectively (P0.01). The overall image quality of SSFSE-C (mean AUCVGC, 0.03; P0.01) and SSFSE-DL (mean AUCVGC, 0.23; P0.01) was rated as significantly inferior, whereas that of SSFSE-DLF (mean AUCVGC, 0.69) was equivalent or significantly higher (P0.01).Using a combination of DL and a sharpening filter markedly increases the image quality of SSFSE of the uterus to the level of the PROPELLER sequence.

TPS276 Background: Non-operative management (NOM) may enable more patients (pts) with a complete clinical response (cCR) or near-complete clinical response (nCR) after total neoadjuvant therapy (TNT) for locally advanced rectal cancer (LARC) to avoid subsequent radical surgery, possibly maintaining the anorectal function and quality of life (QoL). The PRODIGE-23 trial demonstrated that triplet regimen before chemoradiotherapy (CRT) significantly improved outcomes in comparison to CRT. However, there have been no prospective studies of consolidation triplet versus doublet regimens following short course radiotherapy (SCRT). This randomized phase III trial aimed to test the superiority of consolidation CAPOXIRI vs. CAPOX after SCRT as TNT in pts with LARC. Methods: Pts of >18 years of age, with an ECOG PS of 0-1, biopsy-proven newly diagnosed primary LARC (5 cm. The experimental treatment group receives SCRT (5 × 5 Gy) followed by six cycles of CAPOXIRI (capecitabine 800 mg/m2 [orally, twice daily, day 1-14], oxaliplatin 130 mg/m2 [intravenously, day 1] and irinotecan 200 mg/m2 [intravenously, day 1, q3wks]). The standard-of-care group receives SCRT (5 × 5 Gy) followed by six cycles of CAPOX (capecitabine 1000 mg/m2 [orally, twice daily, day 1-14], oxaliplatin 130 mg/m2 [intravenously, day 1, q3wks]). All patients will be restaged after completing TNT before radical surgery according to the Memorial Sloan Kettering Regression Schema; pts with an incomplete response (iCR) will undergo total mesorectal excision (TME), cCR pts will receive NOM, and nCR pts will undergo TME or NOM at the physician’s discretion under the recommendation of blind assessment by the designated NOM central committee. Pts will be followed by CT, MRI, colonoscopy and liquid biopsy every 4 months for 2 years, then every 6 months to 5 years. The primary endpoint is organ preservation-adapted disease-free survival (DFS) in the intention-to-treat population. To detect a decrease in 3-year cumulative probability of organ preservation-adapted DFS from 75.0% to 80.6%, corresponding to a target hazard ratio of 0.75, 608 pts (196 events) would achieve 70% power at a two-sided α of 0.05. Key secondary endpoints include DFS, overall survival, adverse events and QoL. Translational research includes genomic profiling with whole genome/transcriptome sequencing of tissue and blood samples, and the establishment of NOM predictor by deep learning. This study will start in October 2022. Clinical trial information: jRCTs031220342 .

Background: Strong correlation has been reported between tissue water diffusivity and tissue elasticity in the liver. The purpose of this study is to explore the capability of diffusion–based virtual MR elastography (VMRE) in the characterization of liver tumors by extending beyond liver fibrosis assessments. Methods: Fifty-four patients (56 liver tumors: hepatocellular carcinoma (HCC), 31, metastases, 25) who underwent MRE, diffusion-weighted imaging (DWI) (b: 0, 800 s/mm2), and VMRE (b: 200, 1500 s/mm2) were enrolled. The MRE shear modulus (µMRE), apparent diffusion coefficient (ADC), and shifted ADC (sADC) were obtained. Virtual stiffness (µdiff) was estimated from the relationship between µMRE and sADC. A linear discriminant analysis combining VMRE and MRE to classify HCC and metastases was performed in a training cohort (thirty-two patients) to estimate a classifier (C), and evaluate its accuracy in a testing cohort (twenty-two patients). Pearson’s correlations between µMRE, sADC, and ADC were evaluated. In addition to the discriminant analysis, a receiver operating characteristic (ROC) curve was used to assess the discrimination capability between HCC and metastases. Results: The correlations between µMRE and sADC were significant for liver, HCC, and metastases (r = 0.91, 0.68, 0.71, all p &lt, 0.05). Those between µMRE and ADC were weaker and significant only for metastases (r = 0.17, 0.20, 0.55). µdiff values were not significantly different between HCC and metastases (p = 0.56). Areas under the curves (AUC) to differentiate HCC from metastases were as follows: VMRE, 0.46, MRE alone, 0.89, MRE + VMRE, 0.96. The classifier C also provided better performance than MRE alone, in terms of sensitivity (100 vs. 93.5%, respectively) and specificity (92 vs. 76%, respectively, p = 0.046). Conclusions: The correlation between sADC and µMRE was strong both in the liver and in tumors. However, VMRE alone could not classify HCC and metastases. The combination of MRE and VMRE, however, allowed discriminant performance between HCC and metastases.

Purpose: To compare the accuracy of liver fibrosis staging with MR elastography and of staging with extracellular volume fraction (fECV) analysis using contrast-enhanced CT. Methods: This retrospective study included 60 patients who underwent both MR elastography and contrast-enhanced CT before liver surgery between October 2013 and July 2020. Two radiologists independently measured liver stiffness of MR elastography and fECV of CT images. Accuracy for liver fibrosis staging was assessed using receiver operating characteristic (ROC) analysis. Correlations between liver stiffness or fECV and liver fibrosis were also evaluated by means of the Spearman rank correlation coefficient. Results: The areas under the ROC curves for MR elastography for each stage differentiation of ≥F1 (0.85, 0.82 for the two radiologists), ≥F2 (0.88, 0.89), ≥F3 (0.87, 0.86), and F4 (0.84, 0.83) were greater than those for fECV analysis with CT (0.64, p = 0.06, 0.69, p = 0.2; 0.62, p < 0.005, 0.63, p < 0.005; 0.62, p < 0.005, 0.62, p < 0.01; and 0.70, p = 0.08, 0.71, p = 0.2, respectively). The correlation coefficients between liver stiffness and liver fibrosis in A0 (0.67, 0.69 for the two radiologists), A1 (0.64, 0.66) and A2 group (0.58, 0.51) were significantly higher than those between fECV and liver fibrosis (0.28, 0.30; 0.27, 0.31; and 0.23, 0.07; p < 0.05 for all comparisons). Conclusion: MR elastography allows for more accurate liver fibrosis staging compared with fECV analysis with CT. In addition, MR elastography may be less affected than fECV analysis by the inflammatory condition.

Approximately 90% of patients are thought to develop bowel dysfunction after low anterior resection (LAR). Although some prognostic factors have been reported, the volumes of defecation-related muscles have not been examined. This retrospective study investigated the association between the preoperative volume of defecation-related muscles and major LARS.Forty-six patients who underwent LAR for rectal cancer between 2013 and 2020 in our institution were analyzed. They had no local residual tumor or local recurrence at the time of the study and no problems with their defecation function pre-operatively. Defecation-related muscle volume measurements were made before surgery, and the patients answered a low anterior resection syndrome (LARS) score questionnaire after surgery. The muscle volume was adjusted by the patient's height squared.Twenty-seven patients (58.7%) developed major LARS. In the univariate analysis, sex, lateral lymph node dissection, and diverting ileostomy as well as muscle volume of the external anal sphincter, pubococcygeal + iliococcygeus muscle, and puborectal muscle were associated with major LARS. In a multivariate analysis, pubococcygeal + iliococcygeus muscle ( 5.96 ml/mMeasuring the volume of the defecation-related muscles may aid in predicting major LARS.

Background The presence of lateral pelvic lymph node (LLN) metastasis is an essential prognostic factor in rectal cancer patients. Thus, preoperative diagnosis of LLN metastasis is clinically important to determine the therapeutic strategy. The aim of this study was to evaluate the efficacy of preoperative positron emission tomography/computed tomography (PET/CT) in the diagnosis of LLN metastasis. Methods Eighty-four patients with rectal cancer who underwent LLN dissection at Osaka University were included in this study. The maximum standardized uptake value (SUVmax) of the primary tumor and LLN were preoperatively calculated using PET/CT. Simultaneously, the short axis of the lymph node was measured using multi-detector row computed tomography (MDCT). The presence of metastases was evaluated by postoperative pathological examination. Results Of the 84 patients, LLN metastases developed in the left, right, and both LLN regions in 6, 7, and 2 patients, respectively. The diagnosis of the metastases was predicted with a sensitivity of 82%, specificity of 93%, positive predictive value of 58%, negative predictive value of 98%, false positive value of 7%, and false negative value of 18% when the cutoff value of the LLN SUVmax was set at 1.5. The cutoff value of the short axis set at 7 mm on MDCT was most useful in diagnosing LLN metastases, but SUVmax was even more useful in terms of specificity. Conclusions The cutoff value of 1.5 for lymph node SUVmax in PET is a reasonable measure to predict the risk of preoperative LLN metastases in rectal cancer patients.

The introduction of molecularly targeted drugs, including imatinib, has greatly improved the prognosis of gastrointestinal stromal tumor (GIST), and based on the different response image, the methods of response evaluation have been established for GISTs. Furthrmore, the best response evaluation using them has been reported to be associated with progression-free survival (PFS) in imatinib treatment. However, since it is more important to predict the clinical outcomes of imatinib treatment in “early treatment phase”, new predicting factor in earlier stage is desired to work out the whole strategy of each patient. Early morphological change (EMC) was previously reported as a predictive marker for molecularly targeted drugs in metastatic colorectal cancer. The purpose of the present study was to verify the efficacy of EMC in predicting the outcome in patients with GIST receiving imatinib at early evaluation. We retrospectively reviewed 66 patients. EMC in computed tomography (CT) image was evaluated, and the patients were categorized into two groups: active MR (morphological response) (+) group and active MR (−) group. We investigated the association between the presence of active MR and clinical outcomes. Forty-five patients had active MR ( +). The median progression-free survival (PFS) in patients with/without active MR was 49/23 months (P = 0.0039). The evaluation criteria based on EMC could be a sensitive method to predict the clinical outcome of imatinib treatment for patients with unresectable GIST.

To evaluate prescan findings of uterine position and intrapelvic motions that predict the non-diagnostic image quality of three-dimensional T2-weighted MRI (3D-T2WI) of the uterus.This retrospective study included 287 women who underwent pelvic MRI including 3D-T2WI and short prescans consisting of 2D-T2WI and cine imaging. One radiologist classified 3D-T2WI of the uterus as being of diagnostic or non-diagnostic image quality and evaluated the prescans regarding uterine position and intrapelvic motions. Multivariate logistic regression analysis was performed to identify predictors of non-diagnostic 3D-T2WI. The predictive ability of the prescans was verified by two independent MRI technologists.Non-diagnostic 3D T2WI was found in 42 patients (14.6 %) and was significantly associated with severe motions of urinary flow in the bladder (p0.001), small bowel (p = 0.039), and respiration (p0.001). In the multivariate analysis of uterine position and intrapelvic motions, risk factors for the non-diagnostic image quality were prominent urinary flow when the uterus contacted the bladder (p0.001, adjusted odds ratio = 35.1) and severe respiratory and small bowel motions when the uterus was surrounded by the bowel (p0.001, adjusted odds ratio = 68.4). No risk factors were found for the uterus contacting the vertebrae. With these predictors, the prescans demonstrated a sensitivity of 82.9 and 68.3 %, and specificity of 88.2 and 93.9 % for the non-diagnostic 3D-T2WI by the two technologists, respectively.Intrapelvic motions have a different effect on the image quality of 3D-T2WI depending on the uterine position, and short prescans may be useful in predicting time-consuming non-diagnostic 3D-T2WI of the uterus.

A newly developed Adaptive Image Receive (AIR) coil is designed to be more flexible to conform to the human body habitus, and may improve image quality by reducing the distance between the coil element and the imaging subject. This study evaluated the AIR coil's usefulness for liver MR imaging at 3.0 T in comparison with that of a conventional coil retrospectively.The study population comprised 50 consecutive patients, who underwent follow-up liver MR examinations with a 3.0-T MR system using both an AIR coil and a conventional coil to evaluate hepatocellular carcinoma. Three-dimensional fat-suppressed T1-weighted gradient-echo images before and after injection of an MRI contrast agent, T2-weighted single-shot fast spin-echo (SSFSE) images, and diffusion-weighted (DW) images obtained with the AIR coil were compared with corresponding images obtained with the conventional coil. One radiologist measured signal-to-noise ratios (SNRs), while two other radiologists used a 3-point scale to independently assess subjective image noise, artifacts, signal uniformity, and overall image quality.SNRs for the AIR coil were significantly higher than those for the conventional coil (P .05). Subjective image noise for the AIR coil on pre- and postcontrast T1-weighted and DW images was lower than for the conventional coil for both readers (P .05). Overall image quality on pre- and postcontrast T1-weighted and DW images for the AIR coil was better than that for the conventional coil for at least one reader (P .05).In comparison with the conventional coil, AIR coil improved SNR and image quality of liver MR imaging.

We report the imaging findings of three ovarian dysgerminomas that coexisted with other germ cell tumors or gonadoblastomas, focusing on the distribution of tumor nests and vascular architecture, which might provide information about the pathogenesis of dysgerminomas. In a 14-year-old female with dysgerminoma and coexisting gonadoblastomas, contrast-enhanced magnetic resonance imaging (MRI) demonstrated a solid mass in the right ovary, which presented as hyperintense lobules on diffusion-weighted imaging separated by fibrovascular septa. Some small nodules were found to exist separately from the lobules (multiplicity) and to include pathological remnants of gonadoblastoma. Large tumor vessels were present at the center of the mass (central blood vessels), which were in direct contact with the ovarian veins and radiated peripherally through the fibrovascular septa. In a 35-year-old female, a mixed germ cell tumor, which was mainly composed of dysgerminoma and yolk sac tumor foci, exhibited the same vascular architecture pattern as the first dysgerminoma on contrast-enhanced computed tomography. In a 10-year-old female with a mixed germ cell tumor, contrast-enhanced MRI revealed an enlarged left ovary, which contained a large heterogeneous mass and multiple tiny nodules (multiplicity). Microscopically, the former corresponded to a yolk sac tumor, and the latter corresponded to a dysgerminoma containing remnants of gonadoblastoma. Based on these cases, the presence of tumor nest multiplicity and central blood vessels might aid the diagnosis of dysgerminoma, and these imaging findings might be indicative of the synchronous development of multiple dysgerminomas from primordial germ cells or gonadoblastomas.

Objectives The aim of this study was to evaluate the diagnostic ability of magnetic resonance imaging (MRI) in premenopausal women with G1 endometrial carcinoma. Methods Twenty-six patients underwent T2W, diffusion weighted, and dynamic contrast-enhanced 3-T MRI. The degree of myometrial invasion was pathologically classified into no invasion, shallow (3 mm or less), and more. Two radiologists assessed myometrial invasion on MRI. Diagnostic accuracy, sensitivity, specificity, positive and negative predictive values, AUC, and interobserver agreement were analyzed. Results For assessing myometrial invasion, mean accuracy, sensitivity, specificity, positive predictive values, negative predictive values, and AUC, respectively, were as follows: 63%, 42%, 85%, 79%, 47%, and 0.75. Mean interobserver agreement was fair (k = 0.36). Shallow invasions were underestimated as no invasion on MRI in all 6 cases. Conclusions Magnetic resonance imaging produced false-negative result on half of patients. The misjudgments tended to happen in patients with shallow invasion.

OBJECTIVE The aim of this study was to compare power versus manual injection in bolus shape and image quality on contrast-enhanced magnetic resonance angiography (CE-MRA). MATERIALS AND METHODS Three types of CE-MRA (head-neck 3-dimensional [3D] MRA with a test-bolus technique, thoracic-abdominal 3D MRA with a bolus-tracking technique, and thoracic-abdominal time-resolved 4-dimensional [4D] MRA) were performed after power and manual injection of gadobutrol (0.1 mmol/kg) at 2 mL/s in 12 pigs (6 sets of power and manual injections for each type of CE-MRA). For the quantitative analysis, the signal-to-noise ratio was measured on ascending aorta, descending aorta, brachiocephalic trunk, common carotid artery, and external carotid artery on the 6 sets of head-neck 3D MRA, and on ascending aorta, descending aorta, brachiocephalic trunk, abdominal aorta, celiac trunk, and renal artery on the 6 sets of thoracic-abdominal 3D MRA. Bolus shapes were evaluated on the 6 sets each of test-bolus scans and 4D MRA. For the qualitative analysis, arterial enhancement, superimposition of nontargeted enhancement, and overall image quality were evaluated on 3D MRA. Visibility of bolus transition was assessed on 4D MRA. Intraindividual comparison between power and manual injection was made by paired t test, Wilcoxon rank sum test, and analysis of variance by ranks. RESULTS Signal-to-noise ratio on 3D MRA was statistically higher with power injection than with manual injection (P < 0.001). Bolus shapes (test-bolus, 4D MRA) were represented by a characteristic standard bolus curve (sharp first-pass peak followed by a gentle recirculation peak) in all the 12 scans with power injection, but only in 1 of the 12 scans with manual injection. Standard deviations of time-to-peak enhancement were smaller in power injection than in manual injection. Qualitatively, although both injection methods achieved diagnostic quality on 3D MRA, power injection exhibited significantly higher image quality than manual injection (P = 0.001) due to significantly higher arterial enhancement (P = 0.031) and less superimposition of nontargeted enhancement (P = 0.001). Visibility of bolus transition on 4D MRA was significantly better with power injection than with manual injection (P = 0.031). CONCLUSIONS Compared with manual injection, power injection provides more standardized bolus shapes and higher image quality due to higher arterial enhancement and less superimposition of nontargeted vessels.

This study was conducted in order to evaluate the feasibility of a newly developed half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence for T2-weighted MRI of the female pelvis, in which scanning and post-processing filtering techniques were optimized to minimize blurring and the resultant reduction in signal-to-noise ratio (SNR) was compensated by signal averaging of multiple excitations (multi-NEX), and to compare its image quality with that of a conventional turbo spin echo (TSE) sequence. Fifty females with gynecological disease were prospectively enrolled. They underwent pelvic MRI including sagittal T2-weighted imaging obtained with multi-NEX HASTE (mHASTE) and TSE with acquisition times of 1 m 9 s and 3 m 26 s, respectively. At the prospective reading, mHASTE was reviewed first, and any changes in the image interpretation detected during the subsequent TSE reading were recorded. The SNR and tissue contrast were quantitatively measured. Two radiologists independently assessed tissue conspicuity and overall image quality considering noise, artifacts, and blurring, and visual grading characteristics (VGC) analysis was performed to compare the two sequences. Adding TSE to mHASTE did not change image interpretations in any case. mHASTE produced an equivalent SNR and significantly higher contrast between the myometrium and junctional zone (p

Rapid injection of gadoxetic acid has been shown not to increase tumor enhancement in arterial phase liver MRI for unknown reasons. This study aimed to investigate the effect of injection durations on peak contrast concentration in tumors and to correlate it with signal enhancement in gadoxetic acid-enhanced arterial phase MRI.Gadoxetic acid-enhanced arterial phase MRI was obtained using a bolus-tracking technique with injection durations of 1, 3, and 6s in six rabbits with VX2 liver tumors. The peak concentration of gadoxetic acid in the aorta and tumor was estimated by iopromide-enhanced time-resolved CT using the same injection volume and durations with those for MRI. Signal enhancement on MRI and peak enhancement on CT were compared and correlated.There was no significant difference in MR signal enhancement of tumors among the 3 injection durations (p = 0.87). In CT, shorter injection durations significantly increased peak contrast concentration in the aorta (p0.01) but produced equivalent peak contrast concentration in tumors (p = 0.24). The longer injections resulted in the stronger correlation between peak contrast concentration in CT and MR signal enhancement in tumors (r = 0.31, 0.43, and 0.86 with 1s-, 3s-, and 6s-injection, respectively) with a statistical significance only found with 6s-injection (p = 0.03).Estimation of contrast concentration by CT demonstrated that shorter injections did not increase peak contrast concentration in tumors despite increased peak concentration in the aorta. Furthermore, tumor signal enhancement in gadoxetic acid-enhanced arterial phase MRI was less correlated with the peak contrast concentration with shorter injections.

To evaluate the diagnostic value of dual-phase cone beam CT during hepatic arteriography (CBCTHA) for hepatocellular carcinoma (HCC).Thirty seven patients with unresectable HCC underwent the dual-phase CBCTHA prior to transarterial chemoembolization (TACE). Three blinded observers independently reviewed and compared the first phase CBCTHA images alone and the dual phase CBCTHA images. Diagnostic accuracy was evaluated by the alternative free-response receiver operating characteristic method (Area under the curve: Az value). Sensitivities were analyzed with the paired t test. The analysis was performed for overall HCCs, HCCs up to 1 cm and those larger than 1 cm.For all HCCs and HCCs up to 1 cm, Az value and sensitivity showed no significant difference between the first-phase CBCTHA alone and the dual-phase CBCTHA (Az: 0.81 vs 0.88, P = .07, 0.79 and 0.85, P = .14, sensitivity: 0.61 and 0.73, P = .11, 0.41 and 0.52, P = .33, respectively). For HCCs larger than 1 cm, the mean Az value and sensitivity for the dual-phase CBCTHA were significantly higher than those for the first phase CBCTHA alone (Az: 0.96 vs 0.92, P = .008, sensitivity: 0.85 vs 0.75, P = .013, respectively).The diagnostic accuracy of the dual-phase CBCTHA was superior to that of the first phase CBCTHA alone in the diagnosis of HCC larger than 1 cm.

To evaluate the image quality of upper abdominal CT images reconstructed with model-based iterative reconstruction (MBIR) in comparison with filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) on scans acquired with various radiation exposure dose protocols.This prospective study was approved by our institutional review board, and informed consent was obtained from all 90 patients who underwent both control-dose (CD) and reduced-dose (RD) CT of the upper abdomen (unenhanced: n=45, contrast-enhanced: n=45). The RD scan protocol was randomly selected from three protocols; Protocol A: 12.5% dose, Protocol B: 25% dose, Protocol C: 50% dose. Objective image noise, signal-to-noise (SNR) ratio for the liver parenchyma, visual image score and lesion conspicuity were compared among CD images of FBP and RD images of FBP, ASIR and MBIR.RD images of MBIR yielded significantly lower objective image noise and higher SNR compared with RD images of FBP and ASIR for all protocols (P.01) and CD images of FBP for Protocol C (P.05). Although the subjective image quality of RD images of MBIR was almost acceptable for Protocol C, it was inferior to that of CD images of FBP for Protocols A and B (P.0083). The conspicuity of the small lesions in RD images of MBIR tended to be superior to that in RD images of FBP and ASIR and inferior to that in CD images for Protocols A and B, although the differences were not significant (P.0083).Although 12.5%-dose MBIR images (mean size-specific dose estimates [SSDE] of 1.13mGy) yielded objective image noise and SNR comparable to CD-FBP images, at least a 50% dose (mean SSDE of 4.63mGy) would be needed to maintain the subjective image quality and the lesion conspicuity.

Background Rapid injection of gadoxetic acid is reported to produce more frequent artifacts and lower vascular enhancement on arterial phase liver magnetic resonance imaging (MRI). However, its effect on tumor enhancement and the mechanism of the artifacts remain unclear. Purpose To evaluate the effect of rapid injection of gadoxetic acid on artifacts and tumor enhancement during arterial phase liver MRI, and on arterial blood gases (ABGs) which may explain the cause of the artifacts. Material and Methods ABG analysis was performed in 13 free-breathing rabbits after rapid injection (1 mL/s; injection time = 0.6–0.8 s) of gadoxetic acid (0.025 mmol/kg). Dynamic liver MRI was performed in six anesthetized rabbits with VX2 tumors under a ventilation stoppage after rapid and slow injection (0.25 mL/s; injection time = 2.4–3.2 s) of gadoxetic acid. Artifacts and signal enhancement on arterial phase imaging were compared with those obtained after rapid injection of gadopentetic acid (Gd-DTPA, 0.1 mmol/kg) using a Friedman test or Kruskal–Wallis test. Results ABG analysis did not find any significant changes. Artifacts were not related to injection protocols ( P = 0.95). Aortic enhancement with slow injection of gadoxetic acid was significantly higher than that with rapid injection ( P Conclusion Rapid injection of gadoxetic acid did not affect ABGs and may not be the cause of the artifacts. It lowered vascular enhancement but not arterial tumor enhancement.

Purpose The purpose of this study was to investigate the clinical potential of 2-deoxy-2-[18F]fluoro- d -glucose positron emission tomography/computed tomography (FDG PET/CT) to evaluate histopathologic effects of preoperative chemoradiotherapy (CRT) in pancreatic adenocarcinoma, with particular focus on volumetric PET/CT parameters. Material and methods This study included 25 patients with pancreatic adenocarcinoma who underwent radical surgery after gemcitabine- and S-1-based preoperative-CRT. The extent of residual tumor was graded using the Evans grading systems, and patients with more than 50% destruction of tumor cells were defined as responder. Peak SUV corrected for lean body mass (SULpeak), metabolic tumor volume (MTV) with a threshold of SUV = 2.0, total lesion glycolysis (TLG) of pre- and post-CRT, and reduction rates of SULpeak in those parameters were assessed by PET/CT. These parameters were compared using the student's t-test between responder and non-responder. The treatment effect was also assessed by contingency table analysis divided with median value of each parameter using chi-square tests. Results Eight patients (32%) showed histopathologic poor response (Evans grade I), 11 cases (44%) had mild response (Evans grade IIa), and six cases (24%) had moderate response (Evans grade IIb); therefore, six cases (24%) were assigned to responders and others 19 cases (76%) were non-responders. With regards to volumetric PET parameters, post-CRT SULpeak of responders was significantly lower than that of non-responders (p = 0.013). Post-CRT MTV and TLG were negative for all six cases of responders. There were significant differences between responder and non-responder on the contingency table analysis of post-CRT MTV and TLG status (p = 0.014 for both). Conclusions This study demonstrated that the volumetric PET/CT parameters, higher post-treatment SULpeak and positive MTV/TLG could predict the unfavorable histopathological effects of CRT in patients with pancreatic adenocarcinoma.

To compare the image quality and diagnostic performance of reduced field-of-view (rFOV) versus conventional full field-of-view (fFOV) diffusion-weighted (DW) imaging of endometrial cancer. Fifty women with endometrial cancer underwent preoperative rFOV and fFOV DW imaging. Two radiologists compared the image qualities of both techniques, and five radiologists assessed superficial and deep myometrial invasion using both techniques. The statistical analysis included the Wilcoxon signed-rank test and paired t-test for comparisons of image quality and mean diagnostic values. Distortion, tumour delineation, and overall image quality were significantly better with rFOV DW imaging, compared to fFOV DW imaging (P < 0.05); however, the former was inferior in noise (P < 0.05). Regarding superficial invasion, the mean accuracies of the techniques did not differ statistically (rFOV, 58.0% versus fFOV, 56.0%; P = 0.30). Regarding deep myometrial invasion, rFOV DW imaging yielded significantly better mean accuracy, specificity, and positive predictive values (88.4%, 97.8%, and 91.7%, respectively), compared with fFOV DW imaging (84.8%, 94.1%, and 77.4%, respectively; P = 0.009, 0.005, and 0.011, respectively). Compared with fFOV DW imaging, rFOV DW imaging yielded less distortion, improved image quality and, consequently, better diagnostic performance for deep myometrial invasion of endometrial cancer. • rFOV DWI yields better assessment of deep myometrial invasion in endometrial cancer. • rFOV DWI could not sufficiently evaluate superficial invasion in endometrial cancer. • Distortion, tumour delineation, and overall image quality were improved with rFOV DWI.

Objectives To evaluate the interobserver reliability and value of diffusional kurtosis imaging (DKI) in the assessment of uterine tumors compared with those of conventional diffusion-weighted imaging (DWI). Methods This retrospective study was approved by our institutional review board, which waived the requirement for informed consent. Fifty-eight women (mean age: 55.0 ± 13.6 years; range: 30–89 years) with suspected malignant uterine tumors underwent 3-T magnetic resonance imaging using DKI and DWI. Twelve had coexisting leiomyoma. Two observers analyzed region-of-interest measurements of diffusivity (D), kurtosis (K), and the apparent diffusion coefficient (ADC) of uterine lesions and healthy adjacent tissues. Interobserver agreement was evaluated using the intra-class correlation coefficient (ICC). The mean values were compared using one-way analysis of variance with a post-hoc Tukey’s honestly significant difference test. The diagnostic accuracy of D and ADC in differentiating malignant tumors from benign leiomyomas was analyzed using receiver operating characteristic (ROC) analysis. Results The ICCs between the two observers in evaluating D, K, and the ADC of the malignant tumors were higher than 0.84, suggesting excellent interobserver agreements. The mean D (×10−3 mm2/s) of uterine cancers (1.05 ± 0.41 and 1.09 ± 0.40 for observers 1 and 2, respectively) were significantly lower than those of leiomyoma (1.40 ± 0.37 and 1.56 ± 0.33, respectively; P < 0.05), healthy myometrium (1.72 ± 0.27 and 1.69 ± 0.30, respectively; P < 0.001), and healthy endometrium (1.53 ± 0.35 and 1.42 ± 0.37, respectively; P < 0.005). There was no significant difference in the area under the ROC curve between D and ADC. The mean K of uterine cancers (0.88 ± 0.28 and 0.90 ± 0.23, respectively) were higher than those of myometrium (0.72 ± 0.10 and 0.73 ± 0.10, respectively; P < 0.001), healthy endometrium (0.65 ± 0.13 and 0.60 ± 0.18, respectively; P < 0.001), and leiomyoma (0.76 ± 0.14 and 0.77 ± 0.16, respectively; not significant, P > 0.1). Conclusions Interobserver agreements in evaluating D, K, and ADC were moderate to excellent. D performed equally to conventional DWI in differentiating between benign and malignant uterine lesions. The mean K of malignant uterine lesions was significantly higher than that of non-tumorous myometrium or endometrium.

OBJECTIVE To prospectively evaluate the ability of CT urography with a low-dose multi-phasic excretory phase for opacification of the urinary system. MATERIALS AND METHODS Thirty-two patients underwent CT urography with low-dose multi-phasic s using adaptive iterative dose reduction 3D acquired at 5-, 10-, and 15-minute delays. Opacification scores of the upper urinary tracts and the urinary bladder were assigned for each excretory phase by two radiologists, who recorded whether adequate (>75%) or complete (100%) opacification of the upper urinary tract and urinary bladder was achieved in each patient. Adequate and complete opacification rates of the upper urinary tracts and the urinary bladder were compared among three excretory phases and among combined multi-phasic excretory phases using Cochran's Q test. RESULTS There was no significant difference among three excretory phases with 5-, 10-, and 15-minute delays in adequate (56.3, 43.8, and 63.5%, respectively; P = 0.174) and complete opacification rates (9.3, 15.6, and 18.7%, respectively; P = 0.417) of the upper urinary tracts. Combined tri-phasic excretory phases significantly improved adequate and complete opacification rates to 84.4% and 43.8%, respectively (P = 0.002). In contrast, there were significant differences among three excretory phases for the rate of adequate (31.3, 84.4, and 93.8%, respectively; P

To investigate the validity of determining the contrast medium dose based on body surface area (BSA) for the abdominal contrast-enhanced multi-detector row CT comparing with determining based on body weight (BW).Institutional review committee approval was obtained. In this retrospective study, 191 patients those underwent abdominal contrast-enhanced multi-detector row CT were enrolled. All patients received 96 mL of 320 mg I/mL contrast medium at the rate of 3.2 mL. The iodine dose required to enhance 1 HU of the aorta at the arterial phase and that of liver parenchyma at portal venous phase per BSA were calculated (EUBSA) and evaluated the relationship with BSA. Those per BW were also calculated (EUBW) and evaluated. Estimated enhancement values (EEVs) of the aorta and liver parenchyma with two protocols for dose decision based on BSA and BW were calculated and patient-to-patient variability was compared between two protocols using the Levene test.The mean of EUBSA and EUBW were 0.0621 g I/m2/HU and 0.00178 g I/kg/HU for the aorta, and 0.342 g I/m2/HU and 0.00978 g I/kg/HU for the liver parenchyma, respectively. In the aortic enhancement, EUBSA was almost constant regardless of BSA, and the mean absolute deviation of the EEV with the BSA protocol was significantly lower than that with the BW protocol (P.001), although there was no significant difference between two protocols in the hepatic parenchymal enhancement (P=.92).For the aortic enhancement, determining the contrast medium dose based on BSA was considered to improve patient-to-patient enhancement variability.

This study was aimed to compare the accuracy, sensitivity, and positive predictive value of C-arm CT (CACT) during selective transcatheter angiography with those of multidetector CT (MDCT) in the detection of hepatocellular carcinoma (HCC).In this prospective study, 30 patients (mean age, 73 years) with unresectable HCC were examined with CACT before chemoembolisation. Images of a combination of CACT during arterial portography (CACTAP) and dual-phase CACT during hepatic arteriography (CACTHA) was obtained and images of intravenous contrast-enhanced, biphasic, dynamic, MDCT was also obtained beforehand. Three blinded observers independently reviewed CACT and MDCT. Diagnostic accuracy was evaluated by the alternative free-response receiver operating characteristic (AFROC) method. Sensitivities and positive predictive values (PPV) were analyzed with the paired t-test.In the mean area under the AFROC curve (Az), there was no significant difference between MDCT and CACT (MDCT, mean Az value, 0.83; CACT, 0.85, respectively) (P = 0.32). There was also no significant difference between the two techniques in sensitivity (MDCT, mean 0.65; CACT, 0.60) and PPV (MDCT, mean 0.98; CACT, 0.97) (P = 0.40, P = 0.68, respectively).The diagnostic accuracy of CACT was equivalent to that of biphasic CT in the diagnosis of HCC.C-arm CT helps detection of hepatocellular carcinoma (HCC) during interventional (TACE) treatment. C-arm CT for HCC seemed just as accurate as biphasic CT. TACE can be performed with greater confidence using C-arm CT.

To retrospectively compare the accuracy of detection of hypervascular hepatocellular carcinoma (HCC) by multiphasic multidetector CT and by gadoxetate disodium-enhanced MR imaging. After ethical approval, we analysed a total of 73 hypervascular HCC lesions from 31 patients suspected of having HCC, who underwent both gadoxetate disodium-enhanced MR imaging and multiphasic multidetector CT. Five blinded observers independently reviewed CT images, as well as dynamic MR images alone and combined with hepatobiliary phase MR images. Diagnostic accuracy (Az values), sensitivities and positive predictive values were compared by using the Scheffe post hoc test. The mean Az value for dynamic and hepatobiliary phase MR combined (0.81) or dynamic MR images alone (0.78) was significantly higher than that for CT images (0.67, P

To prospectively evaluate the efficacy of a new three-dimensional gradient-echo sequence (Turbo LAVA) that uses undersampled k-space acquisition combined with a two-dimensional parallel imaging technique for hepatobiliary MRI.Sixty patients underwent T1-weighted gadoxetic acid-enhanced hepatobiliary axial MRI during a single breath-hold using both Turbo LAVA (thickness/interval=1.6/0.8mm) and conventional three-dimensional gradient-echo (4/2mm; LAVA) sequences at 3T. Axial 4-mm-thick reformation was performed from Turbo LAVA images. Portal vein-to-liver contrast (PLC), bile duct-to-liver contrast (BLC), and lesion-to-liver contrast (LLC) were compared. Two radiologists independently assessed image quality using a five-point scale. Sagittal 4-mm-thick multiplanar reconstructions (MPR) were performed from both sequences and assessed together with directly obtained 4-mm-thick sagittal LAVA images in terms of sharpness. The paired t-test was used to compare PLC, BLC, and LLC. The Wilcoxon signed rank test was used to compare five-point scales.The mean PLC (P0.001), BLC (P0.001), and LLC (P0.005) were significantly higher for Turbo LAVA than for LAVA; the scores for image noise and sharpness were inferior (P=0.000 and 0.005) and superior (0.005 and 0.157) for Turbo LAVA. There were no significant differences in the scores for bile duct visualization, artifacts, fat suppression quality, overall quality, and focal lesion conspicuity. For sagittal images, MPR Turbo LAVA showed significantly better sharpness than MPR LAVA but showed significantly worse sharpness compared with directly obtained LAVA.High-spatial-resolution single-breath-hold hepatobiliary MRI using Turbo LAVA was feasible. Diagnostic-quality MPR images can be obtained using this sequence.

The objective of this study was to characterize MRI findings of inverted urothelial papilloma of the bladder.Data pertaining to 16 patients with 18 pathologically proven inverted urothelial papillomas of the bladder who had undergone MRI were retrospectively collected from seven institutions. The shape and surface characteristics of the tumors were evaluated using T2-weighted MR images. In addition, the signal intensity of inverted urothelial papillomas was visually assessed on T1-weighted, T2-weighted, and DW images and on early and delayed phase contrast-enhanced images.The shape of the 18 inverted urothelial papillomas of the bladder was classified as polypoid with a stalk for 16 tumors (89%) and polypoid without a stalk for two tumors (11%). All stalks were surrounded by urine in the bladder. A total of 15 of the tumor surfaces (83%) were nonpapillary and three (17%) were papillary. All 12 of the inverted urothelial papillomas for which evaluable T1-weighted images were available were isointense with the bladder wall. The lesions had a slightly higher signal intensity than the bladder wall in 15 of the patients (83%) and showed isointensity with the bladder wall in three patients (17%). A total of three patients (17%) had tiny hyperintense foci noted on T2-weighted images. All 16 of the inverted urothelial papillomas examined by DWI had very high signal intensity. All 13 of the lesions for which early phase images were obtained using dynamic contrast-enhanced MRI showed strong enhancement. When compared with early phase images, delayed phase images of the same 13 lesions showed that enhancement was stronger in two lesions (15%), similar in six lesions (46%), and weaker in five lesions (38%).On MRI, the typical appearance of inverted urothelial papillomas of the bladder is a polypoid shape with a nonpapillary surface and a thin short stalk surrounded by urine. Cystic foci are also occasionally seen within the tumor.

Transcatheter embolotherapy (TCE), a common procedure for interventional radiologists, comprises transcatheter delivery of embolic agents into target vessels in order to eliminate lesions or lesion-associated symptoms. Good knowledge of delivery catheters and embolic agents is essential to optimize embolization techniques and to obtain the desired therapeutic outcomes. In this review, we describe the principles and techniques of TCE for peripheral arterial and venous lesions featuring visceral aneurysms, peripheral and pulmonary arteriovenous malformations (AVMs), and varicoceles.

ObjectiveTo evaluate the image quality and radiation dose reduction in pelvic computed tomography (CT) achieved with an adaptive iterative dose reduction 3-dimensional (AIDR 3D) algorithm using a phantom model.MethodsTwo phantoms were scanned using a 320-detector row CT scanner with 8 tube current levels, and the images were reconstructed with a standard filtered back projection (FBP) algorithm and with an AIDR 3D algorithm.ResultsCompared with FBP, AIDR 3D reduced image noise and improved contrast-to-noise ratios. The diagnostic performance for detection of low-contrast targets of AIDR 3D images obtained with 100 mA at 120 kVp was almost as good as that of the FBP images obtained with 200 mA.ConclusionsThe AIDR 3D algorithm substantially reduced image noise and improved the image quality of pelvic CT images compared with those obtained with the FBP algorithm and can thus be considered a promising technique for low-dose pelvic CT examinations.

Gastric-type adenocarcinoma (GAS) of the uterine cervix is a recently defined subtype of mucinous adenocarcinoma. GAS is proposed to include minimal deviation adenocarcinoma (MDA) as a very well-differentiated form and has been suggested to arise from lobular endocervical glandular hyperplasia (LEGH). We report the magnetic resonance imaging (MRI) findings of a GAS associated with LEGH. On MRI, the LEGH component was detected as multiple cystic lesions arranged in a "cosmos pattern", while the GAS was depicted as a predominantly solid lesion containing obvious adenocarcinoma and MDA components, which appeared as mass-like and infiltrative components, respectively. The GAS exhibited tiny cysts on three-dimensional T2-weighted images, high intensity on diffusion-weighted images mostly due to T2 shine-through effect according to apparent diffusion coefficient (ADC) map, and reticular enhancement on dynamic contrast-enhanced MRI, which reflected numerous dilated glandular structures of the tumor. Low ADC was only observed at the deepest invasion front of the obvious adenocarcinoma component. Our case suggests that the MRI features of GAS vary depending on the tumor's histological components, and it is important to be aware of these imaging features when evaluating LEGH on MRI.

OBJECTIVES This article describes magnetic resonance imaging (MRI) findings in 3 cases of atypical polypoid adenomyoma (APAM). METHODS Clinical and MRI manifestations of 3 patients with APAM were evaluated. High b value diffusion-weighted and dynamic contrast-enhanced images were performed. The size, shape, site of origin, and signal intensity (SI) of MRI findings were evaluated. RESULTS All patients (age range, 37-47 years; mean age, 40 years) had a chief complaint of atypical genital bleeding with no history of pregnancy. In 2 cases, cytology of the endometrium was positive, and pathological analysis of curettage specimens indicated endometrioid adenocarcinoma. The MRI revealed an endometrial polypoid mass arising from the upper corpus (50%) or lower uterine segment (50%). Except for 1 tumor that seemed to invade the myometrium of the uterine wall due to its irregular margin, all tumors were well circumscribed. On T2-weighted MRI scans, the SI of the tumor was homogenous and marginally hyperintense, and contained markedly hyperintense cystic foci. On T1-weighted images, all the tumors were isointense relative to the myometrium, and in 1 case, a number of cystic foci showed high SIs. In a dynamic contrast-enhanced study, solid portions other than the cystic foci showed contrast enhancement in the arterial phase and demonstrated a washout pattern or plateau pattern in the late phase. All tumors demonstrated high SIs on diffusion-weighted images. CONCLUSIONS Differentiating APAM from other malignant polypoid uterine endometrial tumors may still pose difficulties, especially when the tumor seems to invade the myometrium on MRI. Comprehensive clinical information about the patient including age, pathological assessment of the endometrium, and MRI findings should be essential to provide indication for a diagnosis of APAM.