Diagnostic accuracy of segmental enhancement inversion for the diagnosis of renal oncocytoma using biphasic computed tomography (CT) and multiphase contrast-enhanced magnetic resonance imaging (MRI)

Objectives

Segmental enhancement inversion (SEI) is a controversial imaging finding reportedly specific for the diagnosis of renal oncocytoma. The purpose of this study was to re-evaluate SEI using biphasic CT and multiphase MRI.

Methods

With research ethics board approval, a retrospective analysis of patients with resection or biopsy of oncocytoma or chromophobe renal cell carcinoma (Ch-RCC) between 2008-2012 was performed. Twenty-four patients with oncocytoma and 13 patients with Ch-RCC underwent CT, while 13 patients with oncocytoma and 10 patients with Ch-RCC underwent MRI. Two blinded radiologists reviewed the CT and MRI studies independently in separate sessions to assess for SEI. A third radiologist established consensus. Interobserver variability was calculated and diagnostic accuracy was compared using ROC and the Fisher exact test.

Results

There was no difference in detection of SEI between oncocytoma and Ch-RCC at CT [both readers (p?=?0.65, 0.5) and consensus review (p?=?0.29)] or MRI [both readers (p?=?0.64, 0.74) and consensus review (p?=?0.53)]. The interobserver variability at CT (K?=?0.28-0.33) and MRI (K?=?0.25-0.44) was fair. The sensitivity and specificity for diagnosis of oncocytoma were 21 % and 92 % at CT and 15 % and 90 % at MRI.

Conclusion

SEI is not useful for the diagnosis of renal oncocytoma with CT or MRI.

Key Points

? SEI was detected in a minority of renal oncocytomas and chromophobe RCC. ? Interobserver agreement for segmental enhancement inversion was only fair. ? SEI is not useful for diagnosing renal oncocytoma with CT or MRI.     

MSCT对肾脏嗜酸细胞瘤的诊断价值

目的：探讨肾脏嗜酸细胞瘤的CT表现,以提高对该病的认识和诊断水平。方法回顾分析13例经手术、病理证实的嗜酸细胞瘤的CT特征,并与病理结果进行对照。结果13例患者均为单发,7例位于右肾,6例位于左肾,10例向肾实质、肾盂方向生长,3例向肾外生长。CT平扫肿瘤主要呈等密度,2例可见钙化,增强主要表现为病灶明显强化,各期低于肾皮质但高于周围肌组织,强化特征呈“速升缓降”型;5例皮质期可见“轮辐状”强化,4例病灶内见低密度星状瘢痕影,3例可见囊状低密度影,1例病灶周围见出血。结论肾脏嗜酸细胞瘤的CT表现具有一定特征性,但特异性不高,最后诊断常需依靠病理证实。     

肾嗜酸细胞腺瘤与嫌色细胞癌的CT鉴别诊断

肾嗜酸细胞腺瘤与嫌色细胞癌均为少见的肾脏肿瘤,分别占肾细胞肿瘤的3％～7％和6％～11％[1].虽然两者生物学行为不同,由于其起源相同、形态学表现有重叠,导致影像学表现亦有所交叉.本文报告肾嗜酸细胞腺瘤、嫌色细胞癌各1例,回顾性分析其CT表现并结合国内外文献进行讨论,以提高对两种少见肿瘤的影像学认识.     

Diagnostic accuracy and tolerability of contrast enhanced CT colonoscopy in symptomatic patients with increased risk for colorectal cancer

Objective

We compared the accuracy and tolerability of intravenous contrast enhanced spiral computed tomography colonography (CTC) and optical colonoscopy (OC) for the detection of colorectal neoplasia in symptomatic patients for colorectal neoplasia.

Methods

A prospective study was performed in 48 patients with symptomatic patients with increased risk for colorectal cancer. Spiral CTC was performed in supine and prone positions after colonic cleansing. The axial, 2D MPR and virtual endoluminal views were analyzed. Results of spiral CTC were compared with OC which was done within 15 days. The psychometric tolerance test was asked to be performed for both CTC and colonoscopy after the procedure.

Results

Ten lesions in 9 of 48 patients were found in CTC and confirmed with OC. Two masses and eight polyps, consisted of 1 tubulovillous, 1 tubular, 2 villous adenoma, 4 adenomatous polyp, 4 adenocarcinoma, were identified. Lesion prevalence was 21%. Sensitivity, specificity, accuracy, positive and negative predictive values were found 100%, 87%, 89%, 67% and 100%, respectively. Psychometric tolerance test showed that CTC significantly more comfortable comparing with OC (p = 0.00). CTC was the preferred method in 37% while OC was preferred in 6% of patients. In both techniques, the most unpleasant part was bowel cleansing.

Conclusion

Contrast enhanced CTC is a highly accurate method in detecting colorectal lesions. Since the technique was found to be more comfortable and less time consuming compare to OE, it may be preferable in management of symptomatic patients with increased risk for colorectal cancer.     

肾脏嗜酸细胞腺瘤的CT征象分析与鉴别诊断

目的：探讨肾脏嗜酸细胞腺瘤（Renal Oncocytoma，RO）的CT表现，以提高对其诊断的准确性。方法：回顾性分析经病理证实的12例RO的CT资料，全部经MSCT多期检查，包括平扫、增强皮质期、髓质期和排泄期（5例）。结果：病灶全部单发，7例位于左肾，5例位于右肾，最大径2．0-11．6cm，平均5．8em，小于3．0cm者3例。皮质期，10例病灶明显强化，其中8例强化低于肾皮质，2例强化接近于肾皮质。髓质期，7例强化下降并低于肾脏髓质，3例持续强化但在排泄期见密度开始下降。2例在皮质期至排泄期表现为持续性强化。6例见星芒样瘢痕，8例见完整包膜，3例见钙化。结论：大部分RO为富血供。增强后实质部分均匀强化，囊变或坏死罕见，有助于与肾透明细胞癌及肾嫌色细胞癌等相鉴别。     

CT相对强化比值鉴别肾嗜酸性细胞瘤与肾透明细胞癌的应用价值

目的:探讨CT相对强化比值(病灶/肾皮质密度比值)鉴别肾嗜酸性细胞瘤(RO)与肾透明细胞癌(RCC)的应用价值.方法:回顾性分析经手术病理证实的14例RO和32例RCC的CT强化特征.分别测量两组病例CT增强各时相病灶强化区域及相邻肾皮质密度,比较各时相病灶CT值和病灶/肾皮质密度比值.采用独立样本t检验及卡方检验对测量结果进行统计学分析.结果:RCC于CT增强皮质期、髓质期和肾盂期测得的病灶CT绝对值均高于RO,但差异无统计学意义(P均＞0.05);27例RCC(27/32,占84％)皮质期病灶/肾皮质密度比值＞1,仅1例RO(1/14,占93％)病灶/肾皮质密度比值＞1,两者间差异具有统计学意义(P＜0.05);10例RO(10/14,占71％)髓质期病灶/肾皮质密度比值高于皮质期,呈“延迟强化”表现,仅1例RCC(1/32,占3％)髓质期病灶/肾皮质密度比值高于皮质期,呈“延迟强化”表现,两者间差异具有统计学意义(P＜0.05).以皮质期病灶/肾皮质密度比值＜1为标准,诊断RO的敏感度、特异度、阳性预测值、阴性预测值、准确性分别为93％、84％、72％、84％和87％;以髓质期病灶/肾皮质密度比值高于皮质期为标准,诊断RO的敏感度、特异度、阳性预测值、阴性预测值、准确性分别71％、97％、91％、91％和89％.结论:应用CT相对强化比值(病灶/肾皮质密度比值)分析法有助于鉴别RO与RCC.     

Diagnostic accuracy of low-dose and ultra-low-dose CT in detection of chest pathology: a systematic review

PurposeStudies have evaluated imaging modalities with a lower radiation dose than standard-dose CT (SD-CT) for chest examination. This systematic review aimed to summarize evidence on diagnostic accuracy of these modalities – low-dose and ultra-low-dose CT (LD- and ULD-CT) – for chest pathology.MethodOvid-MEDLINE, Ovid-EMBASE and the Cochrane Library were systematically searched April 29th–30th, 2019 and screened by two reviewers. Studies on diagnostic accuracy were included if they defined their index tests as ‘LD-CT’, ‘Reduced-dose CT’ or ‘ULD-CT’ and had SD-CT as reference standard. Risk of bias was evaluated on study level using the Quality Assessment of Diagnostic Accuracy Studies-2. A narrative synthesis was conducted to compare the diagnostic accuracy measurements.ResultsOf the 4257 studies identified, 18 were eligible for inclusion. SD-CT (3.17 ± 1.47 mSv) was used as reference standard in all studies to evaluate diagnostic accuracy of LD- (1.22 ± 0.34 mSv) and ULD-CT (0.22 ± 0.05 mSv), respectively. LD-CT had high sensitivities for detection of bronchiectasis (82–96%), honeycomb (75–100%), and varying sensitivities for nodules (63–99%) and ground glass opacities (GGO) (77–91%). ULD-CT had high sensitivities for GGO (93–100%), pneumothorax (100%), consolidations (90–100%), and varying sensitivities for nodules (60–100%) and emphysema (65–90%).ConclusionThe included studies found LD-CT to have high diagnostic accuracy in detection of honeycombing and bronchiectasis and ULD-CT to have high diagnostic accuracy for pneumothorax, consolidations and GGO. Summarizing evidence on diagnostic accuracy of LD- and ULD-CT for other chest pathology was not possible due to varying outcome measures, lack of precision estimates and heterogeneous study design and methodology.     

Diagnostic accuracy of computed tomography and ultrasound for the diagnosis of acute appendicitis: A systematic review and meta-analysis

IntroductionThe diagnosis of acute appendicitis remains challenging. This review determined the current diagnostic accuracy of CT and ultrasound for suspected acute appendicitis in adults.MethodsThis systematic review adhered to the PRISMA for diagnostic test accuracy guidelines. A systematic search was undertaken in appropriate databases. Screening of potential titles and abstracts, full-text retrieval, methodological quality assessment using QUADAS, and data extraction was performed. Meta-analyses were performed for relevant subgroups, and sensitivity analysis was completed to account for outliers. GRADE was utilized to assess the certainty of findings.Results31 studies evaluating CT, 10 evaluating US, and six evaluating both were included. Pooled sensitivity and specificity for CT was 0.972 [0.958, 0.981] and 0.956 [0.941, 0.967] respectively, and 0.821 [0.738, 0.882] and 0.859 [0.727, 0.933] for US, respectively. When analyzing subgroups based on the use of contrast enhancement, sensitivity and specificity was highest for CT with intravenous and oral contrast (0.992 [0.965, 0.998], 0.974 [0.936, 0.99]), compared to CT with intravenous contrast (0.955 [0.922, 0.974], 0.942 [0.916, 0.960]). Low-Dose CT produced comparable values (0.934 [0.885,0.963], 0.937 [0.911, 0.955]) relative to these subgroups and standard dose non-contrast CT (0.877 [0.774,0.937], 0.914 [0.827, 0.959]). US studies which excluded equivocal findings demonstrated significantly greater values than the remainder of US studies (p < 0.0001).ConclusionThe updated diagnostic test accuracies of CT, US and relevant subgroups should be implemented in light of factors such as dose, cost, and timing.Implications for practiceFor diagnosis of adult acute appendicitis:? CT with intravenous plus oral contrast enhancement yields statistically significantly greater diagnostic accuracy than CT with intravenous contrast alone.? Low-dose CT yields comparable sensitivity and specificity to standard-dose CT.? Ultrasound studies which exclude equivocal results may overinflate sensitivity and specificity.     

CT平扫与增强扫描对梗阻性黄疸的诊断价值

目的探讨CT对梗阻性黄疸的诊断价值。方法对38例经手术病理证实的梗阻性黄疸进行回顾性分析。其中，胆管癌9例，胰腺癌12例，胆总管结石16例，胆总管炎性狭窄1例。结果胆管癌中7例位于胆总管，2例位于肝门区胆管，均表现为梗阻上方胆管扩张。胰腺癌中8例表现为胰头增大，4例胰头增大不明显，增强扫描可见小结节状强化。胆总管结石中14例为阳性结石，表现为高密度影，2例为阴性结石，表现为低密度影。胆总管炎性狭窄1例，表现为肝内外胆管扩张，胆囊扩大，胆总管渐进性狭窄。结论CT除可以确定梗阻性黄疸的诊断以外，还能明确梗阻部位以及判断梗阻原因。     

Diagnostic accuracy of Magnetic Resonance Imaging using liver tissue specific contrast agents and contrast enhanced Multi Detector Computed Tomography: A systematic review of diagnostic test in Hepatocellular Carcinoma (HCC)

ObjectivesThe aim of this systematic review is to investigate diagnostic accuracy of Magnetic Resonance Imaging (MRI) scans using liver specific tissue contrast media over contrast enhanced Multi Detector CT (MDCT) in diagnoses of Hepatocellular Carcinoma (HCC) in patients with chronic liver disease.Key findingsA total of 8 diagnostic studies were identified and generally considered of high quality. The studies reported sufficient evidence on sensitivity and specificity, which was synthesised and summarised providing an overview of the evidence. Findings indicate that MRI scans using liver specific tissue contrast have a better diagnostic performance compared to contrast enhanced MDCT in diagnostic work-up of HCC in patients with chronic liver disease.ConclusionThe current review identified sufficient high quality studies reporting statistical difference (P < 0.05), to establish the superiority of gadoxetetic acid enhanced MRI for sensitivity and specificity in comparison to MDCT in the diagnosis of HCC in chronic liver disease.     

双能CT双期增强扫描结合虚拟平扫对肾脏透明细胞癌的诊断价值

目的 探讨双能CT双期增强结合虚拟平扫对肾脏透明细胞癌的诊断价值.方法 对60例临床怀疑肾脏透明细胞癌的患者进行前瞻性研究,进行双能CT的单能平扫及双能皮髓交界早期、实质期增强扫描,采用虚拟平扫后处理软件生成虚拟平扫图像,分别根据虚拟平扫结合双期增强及单纯双期增强图像进行诊断,以病理结果为标准,计算两者诊断肾脏透明细胞癌的准确率,并以x2检验比较;以Wilcoxon秩和检验比较常规平扫和虚拟平扫图像对肿瘤的显示;以配对样本t检验比较患者所接受的单期X线辐射剂量和总辐射剂量差异、常规平扫与虚拟平扫图像肿瘤的CT值差异.结果 虚拟平扫结合双能CT双期增强图像对透明细胞癌的诊断准确率高于单纯双期增强[分别为93.3％ (56/60)和78.3％ (47/60);x2=5.6,P＜0.05].常规平扫显示42例肾透明细胞癌病灶,对肿瘤显示优、良、一般和差的分别为22、12、4和4例,虚拟平扫分别为26、10、3和3例,差异无统计学意义(Z=0.00,P=1.00).虚拟平扫的单期CTDIvol(8.85±1.28) mGy、DLP剂量(196.45±21.12) mGy·cm和总的CTDIvol( 17.69±2.35) mGy、DLP剂量(392.90±42.25) mGy·cm均低于常规平扫[分别为(10.20±1.44)mGy、(218.29±29.60) mGy·cm、(30.61±3.27) mGy和(654.86±88.81)mGy·cm],t值分别为4.21、3.58、23.63、16.12,P值均＜0.05.常规平扫和虚拟平扫的CT值分别为(34.94±7.00)和(39.37±6.35)HU,差异有统计学意义(t=-14.39,P＜0.05).结论 双能CT皮髓交界早期及实质期双期增强结合虚拟平扫对肾脏透明细胞癌的诊断价值较大,对多数患者可以做出准确诊断,并明显降低辐射剂量.     

多层螺旋CT增强检查对乳腺病变的诊断价值

目的:探讨多层螺旋CT(MSCT)增强检查对乳腺疾病的鉴别诊断价值。方法:经手术病理证实的84位患者,共检出93例乳腺病变,其中浸润性导管癌57例,粘液癌4例,纤维腺瘤13例,导管内乳头状瘤4例,其他良性病变15例。CT检查先平扫,而后分别于静脉注射对比剂后28s、90s时进行二期增强扫描。对照手术病理结果,分析所有乳腺病变的CT表现。结果:乳腺良、恶性病变的平扫密度之间的差异无统计意义(P>0.05)。乳腺良、恶性病变的形状、边缘及强化形式之间的差异有统计意义(P=1.57×10-4;P=1.75×10-28;P=1.78×10-2)。以25HU为分界点,本组乳腺良、恶性病变动脉期强化程度之间的差别有高度统计意义(P<0.001)。MSCT诊断本组乳腺病变的敏感性为96.7%,特异性为90.6%,阳性预测值为95.2%,阴性预测值为93.5%。MSCT对61例乳腺癌腋窝淋巴结转移的术前检出率为88.8%。结论:多层螺旋CT增强检查在鉴别乳腺良恶性病变方面具有较高的诊断价值。     

Diagnostic accuracy of integrated FDG-PET/contrast-enhanced CT in staging ovarian cancer: comparison with enhanced CT

Purpose  The purpose of the study is to evaluate the accuracy of integrated positron emission tomography and computed tomography (PET/CT) with ¹⁸F-fluorodeoxyglucose (FDG) with IV contrast for preoperative staging of ovarian cancer, in comparison with enhanced CT, using surgical and histopathological findings as the reference standard. Materials and methods  Forty patients with ovarian cancer underwent FDG-PET/contrast-enhanced CT scans for staging before primary debulking surgery. PET/CT and the CT component separately, were interpreted by two experienced radiologists by consensus for each investigation. Status with regard to lesion inside and outside the pelvis was determined on the basis of histopathology. The significance of differences between the two imaging modalities was determined using the McNemar test. Results  Staging revealed stage I in 18 patients (IA, n = 9; IB, n = 3; IC, n = 6), stage II in seven (IIA, n = 2; IIB, n = 3; IIC, n = 2), stage III in 14 (IIIA, n = 1; IIIB, n = 3; IIIC, n = 10), and stage IV in one. The results of CT and PET/CT were concordant with the final pathological staging in 22 out of 40 (55%) and 30 out of 40 (75%) cases, respectively. The overall lesion-based sensitivity improved from 37.6% (32 out of 85) to 69.4% (59 out of 85), specificity from 97.1% (578 out of 595) to 97.5% (580 out of 595), and accuracy from 89.7% (610 out of 680) to 94.0% (639 out of 680) between CT and PET/CT. There were significant differences in sensitivity and accuracy, with p values of 5.6 × 10⁻⁷ and 1.2 × 10⁻⁷, respectively. Conclusion  Integrated FDG-PET/contrast-enhanced CT is a more accurate imaging modality for staging ovarian cancer and useful for selecting appropriate treatment than enhanced CT.     

Pulmonary embolism: prospective comparison of iso-osmolar and low-osmolarity nonionic contrast agents for contrast enhancement at CT angiography

PURPOSE: To prospectively evaluate contrast enhancement on pulmonary computed tomographic (CT) angiograms obtained by using an iso-osmolar versus a low-osmolarity contrast agent to exclude pulmonary embolism. MATERIALS AND METHODS: Written patient consent was obtained on a form approved by the institutional review board, and the board approved the study. This prospective, randomized, double-blinded clinical trial included 47 patients referred for multi-detector row CT angiography to exclude pulmonary embolism over a 5-month period. Patients received either iohexol or iodixanol as an intravenous contrast agent. Three radiologists independently evaluated enhancement homogeneity and quality in designated pulmonary artery branches at four consecutive levels in the lower lobe of the left lung from lobar to subsegmental arteries. This evaluation was performed at a workstation separately for homogeneity and quality with two different three-level scales established with consensus. Percentages of each given score were compared with the chi2 test. The mean attenuation (expressed in Hounsfield units) for each contrast agent was compared with Student t test, and interobserver agreement (kappa value) was calculated. RESULTS: The percentages of arteries graded as excellent or not diagnostic were not statistically different (P >.05), with comparison of the two contrast agents at all levels. The intensity of enhancement (quantitative evaluation of enhancement by using mean attenuation of vessel lumen) was similar (P >.05) in the two groups. The kappa values varied from 0.35 to 0.56 among readers. CONCLUSION: Use of an iso-osmolar contrast agent at multi-detector row CT angiography to exclude pulmonary embolism did not significantly improve enhancement quality when this feature was compared with that of a low-osmolarity contrast agent.     

Late contrast enhancement in the CT diagnosis of herniated lumbar disk

Summary Twenty-five patients clinically suspected of herniated lumbar disk have undergone a CT examination before and 40 min after contrast enhancement. In every case, 13 of which were surgically verified, significant contrast enhancement of herniated disks was seen; there was only one false positive case. The authors conclude that late contrast enhancement really improves the CT diagnosis of herniated lumbar disk, particularly in cases with a doubtful or negative precontrast scan. The mechanism of the late contrast enhancement is discussed.     

The role of contrast enhanced ultrasound in the differential diagnosis of segmental testicular infarction

A 43-year-old male presented to the emergency department with acute left testicular pain. Physical exam showed a tender left testicle and epididymis with mild swelling. Doppler and contrast enhanced ultrasound revealed a heterogeneous, avascular lesion with hyper vascularized surrounding. Follow-up contrast enhanced ultrasound performed a few days later showed persistence of the sparsely vascularized lesion with more hypoechoic echo structure.Despite the tumor markers being negative, a necrotic tumor could not be ruled out and a left orchiectomy was performed. Pathology report described an extensive segmental testicular infarction with no evidence of malignant tissue.We present the ultrasound and pathology findings, differential diagnostic pearls and clinical perspective of segmental testicular infarction.