Small colorectal liver metastases: Detection with SPIO-enhanced MRI in comparison with gadobenate dimeglumine-enhanced MRI and CT imaging

The aim of this prospective study was to compare the diagnostic role of superparamagnetic iron oxide (SPIO)-enhanced liver magnetic resonance imaging (MRI) versus gadobenate dimeglumine (GbD)-enhanced MRI and computed tomography (CT) investigations for detection of small (less than 1 cm) colorectal liver metastases (LMs) of colorectal cancer. Seventy-eight LMs in 16 patients were evaluated with dynamic CT imaging, GbD-enhanced dynamic MR imaging and SPIO-enhanced MR imaging. Two radiologists were reviewed the LMs seperately. Agreement between the readers and three algorithms was analyzed. Differences between the lesion detection ratios of the methods were analyzed by two proportion z test. Sensitivity values of each modality were also calculated. Interobserver agreement values with kappa analysis were found to be the best for three modalities and kappa values were 0.866, 0.843, and 1.0 respectively. For all 78 LMs, SPIO-enhanced MRI detected all lesions (100% sensitivity). This sensitivity value was higher than GbD-enhanced MRI, and there was a significant difference (p < 0.05). GbD-enhanced MRI depicted 71 lesions and this modality could not detected 7 lesions (91% sensitivity). This modality had moderate sensitivity, and this value is greater than CT imaging, so there was a significant difference also (p < 0.05). Dynamic triphasic CT imaging detected 64 (R1) and 65 (R2) LMs. This modality had the lowest sensitivity (R1: 0.82, R2: 0.83 respectively). Only SPIO-enhanced MRI was able to detect all LMs less than 1 cm. LMs were the best detected with SPIO-enhanced MRI. We recommend SPIO-enhanced MRI to be the primary alternative modality especially for diagnosis of small colorectal LMs.     

Comparison of FDG-PET, PET/CT and MRI for follow-up of colorectal liver metastases treated with radiofrequency ablation: initial results

PURPOSE: Morphologic imaging after radiofrequency ablation (RFA) of liver metastases is hampered by rim-like enhancement in the ablation margin, making the identification of local tumor progression (LTP) difficult. Follow-up with PET/CT is compared to follow-up with PET alone and MRI after RFA. METHODS AND MATERIALS: Sixteen patients showed 25 FDG-positive colorectal liver metastases in pre-interventional PET/CT. Post-interventional PET/CT was performed 24h after ablation and was repeated after 1, 3 and 6 months and then every 6 months. PET and PET/CT data were compared with MR data sets acquired within 14 days before or after these time points. Either histological proof by biopsy or resection, or a combination of contrast-enhanced CT at fixed time points and clinical data served as a reference. RESULTS: The 25 metastases showed a mean size of 20mm and were treated with 39 RFA sessions. Ten lesions which developed LTP received a second round of RFA; four lesions received three rounds of treatment. The mean follow-up time was 22 months. Seventy-two PET/CT and 57 MR examinations were performed for follow-up. The accuracy and sensitivity for tumor detection was 86% and 76% for PET alone, 91% and 83% for PET/CT and 92% and 75% for MRI, respectively. CONCLUSIONS: In comparison to PET alone, PET/CT was significantly better for detecting LTP after RFA. There were no significant differences between MRI and PET/CT. These preliminary results, however, need further verification.     

Non-invasive diagnostic imaging of colorectal liver metastases

Colorectal cancer is one of the few malignant tumors in which synchronous or metachronous liver metastases [colorectal liver metastases (CRLMs)] may be treated with surgery. It has been demonstrated that resection of CRLMs improves the long-term prognosis. On the other hand, patients with un-resectable CRLMs may benefit from chemotherapy alone or in addition to liver-directed therapies. The choice of the most appropriate therapeutic management of CRLMs depends mostly on the diagnostic imaging. Nowadays, multiple non-invasive imaging modalities are available and those have a pivotal role in the workup of patients with CRLMs. Although extensive research has been performed with regards to the diagnostic performance of ultrasonography, computed tomography, positron emission tomography and magnetic resonance for the detection of CRLMs, the optimal imaging strategies for staging and follow up are still to be established. This largely due to the progressive technological and pharmacological advances which are constantly improving the accuracy of each imaging modality. This review describes the non-invasive imaging approaches of CRLMs reporting the technical features, the clinical indications, the advantages and the potential limitations of each modality, as well as including some information on the development of new imaging modalities, the role of new contrast media and the feasibility of using parametric image analysis as diagnostic marker of presence of CRLMs.     

Diagnostic performance of contrast-enhanced CT-scan in sinusoidal obstruction syndrome induced by chemotherapy of colorectal liver metastases: Radio-pathological correlation

PurposeSinusoidal obstruction syndrome (SOS) is a likely side effect of colorectal liver metastases (CRLM) chemotherapy. This study aimed to assess computed tomography scan (CT-scan) performance for SOS diagnosis for patients receiving neoadjuvant chemotherapy (NC) prior to CRLM surgery, comparing obtained results with pathological gold standard.MethodsPreoperative CT-scans of 67 patients who had received a NC prior to liver resection for CRLM from 2011 to 2016 were retrospectively analysed. Positive diagnosis and severity of SOS were established after consensual review of the slides by three pathologists. Preoperative CT-scans were separately interpreted by two radiologists and evocative signs of SOS were sought, defined according to a literature review and operators experience. In order to identify SOS predictors, univariate analysis and multivariate logistic regression were used to study CT-scan signs and pathological results correlation.ResultsTwenty-nine patient (43%) had an SOS, 22 (33%) were low-grade and 7 (10%) were high-grade. All patient had received a median of 6 cures (3–27) containing Oxaliplatin for 53 (79%) of them. In univariate analysis, hepatic heterogeneity (p < 0.001), puddle-like or micronodular appearance (p < 0.001), peripheral distribution of heterogeneity (p = 0.085), clover-like sign (p = 0.02), splenomegaly (p = 0.0026), spleen volume increase ≥30% (p = 0.04) or splenic length increase ≥15% (p = 0.04), as well as the subjective impression of the observer (P < 0.001) were significantly associated with SOS diagnosis. In multivariate analysis, clover-like sign (OR 1.87, 95% CI 1.18–2.95, p = 0.0081), increase in spleen volume ≥30% (OR 1.29, 95% CI 1.01–1.64, p = 0.04), and the peripheral distribution of heterogeneity (OR 1.53, 95% CI 1.21–1.94, p < 0.001) were independent SOS predictors. The area under the ROC curve was 0.804. The inter-observer agreement for SOS diagnosis was moderate (Kappa = 0.546).ConclusionCT-scan can detect suggestive signs of SOS in patients receiving chemotherapy for CRLM. By integrating clinical and biological information into CT-scan data, it may be fruitful to create a positive diagnostic and severity score for chemotherapy-induced SOS.     

Tuberculous adenitis: comparison of CT and MRI findings with histopathological features

Our aim was to investigate the relationship between the various histopathological features and the CT and MRI findings in routinely submitted histopathological specimens for the diagnosis of tuberculous lymphadenopathy. Twelve formalin-fixed, paraffin-embedded tissue blocks from ten patients who were clinically suspected of having tuberculous lymphadenopathy were evaluated. We assessed the presence of histopathological features including granuloma formation, caseous necrosis, and presence of Langhans-type giant cells, calcifications, fibrosis or normal lymphoid tissue. We performed polymerase chain reaction (PCR)-based assay for mycobacterial DNA and Ziehl-Neelsen staining for acid-fast bacilli (AFB). Findings were compared with those of CT and MRI, including signal intensities on unenhanced MR images, lymph node homogeneity, attenuation values on contrast-enhanced CT and enhancement patterns on MRI. Based on CT and MRI findings, four lymph node types could be defined: (1) homogeneous nodes, visible on both pre- and post-contrast images and corresponding histopathologically to granulation tissue without or with minimal caseation necrosis (n = 2); (2) heterogeneous nodes, showing heterogeneous enhancement patterns with central non-enhancing areas and corresponding to minor or moderate intranodal caseation/liquefaction necrosis (n = 3); (3) nodes showing peripheral rim enhancement and corresponding to moderate or extensive intranodal caseation/liquefaction necrosis (n = 5); (4) heterogeneous nodes showing intranodal hyperdensities on CT and hypointense areas on T1- and T2-weighted images and corresponding to fibrosis and calcifications (n = 2). On CT and MRI, the findings reflect different stages of the tuberculous process. Imaging findings depend on the presence and the degree of granuloma formation, caseation/liquefaction necrosis, fibrosis and calcifications.     

Detection and characterization of benign focal liver lesions with multislice CT

MDCT is a rapidly evolving technique that significantly improves CT imaging for several indications including depiction of focal benign lesions. Imaging mainly profits from improved longitudinal spatial resolution allowing high-quality non-axial reformations and 3D reconstructions and CT angiography as well as rapid accurate multiphase imaging with short breath-holding periods. This review provides an overview of the current status of MDCT with respect to liver imaging and the implications for characterizing benign focal liver lesions. MDCT currently allows the acquisition of thin slices in daily routine diagnostics providing an improved detection rate of small liver lesions. Whereas large benign focal liver lesions exhibit typical patterns of morphology, attenuation and perfusion, which also may be assessed with single-slice scanners, small lesions remain challenging even with MDCT, since the specific criteria for confident diagnosis become more ambiguous. Here, MR imaging provides more detailed information about tissue components and the availability of liver-specific contrast agents, adding further impact to this technique. With respect to dose considerations, the number of necessary multiphase scans as well as the application of very thin collimation should be strictly checked for each patient undergoing MDCT based on the individual clinical situation and question.     

Anterior mediastinal tumors: diagnostic accuracy of CT and MRI

Purpose

To compare the diagnostic accuracy for anterior mediastinal tumors among CT, MRI, and both CT and MRI, and to determine the optimal CT and MRI procedures for the diagnosis of anterior mediastinal tumors.

Materials and methods

Both CT and MRI were performed in 127 patients with pathologically diagnosed anterior mediastinal tumors. The patients included 48 cases of thymoma, 12 cases of thymic carcinoma, 12 cases of thymic cyst, 20 cases of mature teratoma, 13 cases of malignant germ cell tumor, and 22 cases of malignant lymphoma. The CT and MRI scans were assessed by two chest radiologists without knowledge of their clinical and pathologic data. The observers recorded various CT and MRI findings and their first choice of diagnosis.

Results

The two observers made a correct first-choice diagnosis in an average of 78 (61%) of 127 cases on CT, 71 (56%) of 127 cases on MRI, and 85.5 (67%) of 127 cases on both CT and MRI. These included 83% cases of thymoma on CT, 84% on MRI, and 85% on both CT and MRI; 38% cases of thymic carcinoma on CT and 13% on MRI, and 33% on both CT and MRI; 46% cases of thymic cyst on CT and 71% on MRI, and 63% on both CT and MRI; 58% cases of mature teratoma and 38% on MRI, and 78% on both CT and MRI; 35% cases of malignant germ cell tumor on CT and 27% on MRI, and 31% on both CT and MRI; and 55% cases of malignant lymphoma on CT and 43% on MRI, and 61% on both CT and MRI. There were significant differences between the diagnostic accuracy by CT and MRI in the cases with both thymic cysts and thymic carcinoma (p < 0.05).

Conclusion

CT is equal or superior to MRI in the diagnosis of anterior mediastinal tumors except for thymic cyst. CT should be considered the modality of choice following chest radiography, however, in certain circumstances, such as thymic cyst with hemorrhage or inflammation which mimic solid tumor despite low enhancement, MRI may be better in distinguishing anterior mediastinal tumors. For more helpful information in the diagnosis of mature teratoma after CT, MRI may follow.     

Comparison of MRI (including SS SE-EPI and SPIO-enhanced MRI) and FDG-PET/CT for the detection of colorectal liver metastases

Fluoro-18-deoxyglucose positron emission tomography computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI), including unenhanced single-shot spin-echo echo planar imaging (SS SE-EPI) and small paramagnetic iron oxide (SPIO) enhancement, were compared prospectively for detecting colorectal liver metastases. Twenty-four consecutive patients suspected for metastases underwent MRI and FDG-PET/CT. Fourteen patients (58%) had previously received chemotherapy, including seven patients whose chemotherapy was still continuing to within 1 month of the PET/CT study. The mean interval between PET/CT and MRI was 10.2 ± 5.2 days. Histopathology (n = 18) or follow-up imaging (n = 6) were used as reference. Seventy-seven metastases were detected. In nine patients, MRI and PET/CT gave concordant results. Sensitivities for unenhanced SS SE-EPI, MRI without SS SE-EPI and FDG-PET/CT were, respectively, 100% (p = 9 × 10⁻¹⁰ vs PET, p = 8 × 10⁻³ vs MRI without SS SE-EPI), 90% (p = 2 × 10⁻⁷ vs PET) and 60%. PET/CT sensitivity dropped significantly with decreasing size, from 100% in lesions larger than 20 mm (identical to MRI), over 54% in lesions between 10 and 20 mm (p = 3 × 10⁵ versus unenhanced SS SE-EPI), to 32% in lesions under 10 mm (p = 6 × 10⁻⁵ versus unenhanced SS SE-EPI). Positive predictive value of PET was 100% (identical to MRI). MRI, particularly unenhanced SS SE-EPI, has good sensitivity and positive predictive value for detecting liver metastases from colorectal carcinoma. Its sensitivity is better than that of FDG-PET/CT, especially for small lesions.     

Comparison of unenhanced and contrast-enhanced spiral CT for assessing interval change in patients with colorectal liver metastases

RATIONALE AND OBJECTIVES: The purpose of this study was to determine whether the interval change in hepatic colorectal metastases as assessed with serial computed tomographic (CT) scans without contrast material enhancement differs from that as assessed using serial, portal dominant phase, contrast-enhanced CT scans. MATERIALS AND METHODS: Unenhanced and contrast-enhanced abdominal CT scans were obtained in 28 patients. Three radiologists separately reviewed serial unenhanced and contrast-enhanced studies to assess the interval change in liver metastases. These radiologists recorded total number of lesions, bidimensional measurements of the largest lesions (as many as three), and overall impressions regarding the interval change (none, worse, or better). RESULTS: Among the 84 judgments (28 patients x 3 radiologists), comparisons of unenhanced and contrast-enhanced CT studies were concordant in 60 assessments (71%). Nineteen (23%) showed mild disagreement. Of these, contrast-enhanced CT studies demonstrated disease stability when unenhanced CT studies demonstrated otherwise in 11 judgments, whereas unenhanced CT studies demonstrated stability when contrast-enhanced CT studies demonstrated otherwise in eight assessments. Furthermore, of the five marked disagreements, two resulted from a conclusion of interval improvement on unenhanced CT studies and a conclusion of interval worsening on contrast-enhanced CT studies, whereas three demonstrated the opposite. Neither set of serial CT studies systematically resulted in under- or overestimation of disease progression (McNemar Q test, P < .25). CONCLUSION: The authors found no consistent pattern to demonstrate that serial unenhanced or contrast-enhanced CT studies resulted in over- or underestimation of disease progression.     

肝转移瘤高场MRI诊断

目的:探讨高场MRI在肝转移瘤(HMs)中的检出、诊断与鉴别诊断价值。方法:收集经临床、影像证实的HMs 43例,所有病例均进行高场MRI平扫和动脉期、门脉期、延迟期扫描,其中23例尚做螺旋CT平扫、动脉期、门脉期扫描,分析记录HMs螺旋CT、高场MRI平扫及多期增强扫描特征。结果:共计174枚瘤灶在MRI平扫上呈长T2长T1信号,动脉期122枚瘤灶不强化,门脉期174枚瘤灶均呈环状强化,延迟期108枚瘤灶呈向心性充填;23例79枚瘤灶螺旋CT平扫均呈低密度,动脉期49枚瘤灶不强化,30枚呈环状强化,门脉期73枚呈环状强化,4枚呈向心性充填;43例HMs高场MRI均准确诊断,螺旋CT漏检2例,误诊7例。结论:高场MRI对HMs的检出、诊断与鉴别诊断具重要价值,可作为HMs的首选检查方法。     

肝脏孤立性坏死结节的MRI表现

目的 总结肝脏孤立性坏死结节(SNN)平扫和动态增强MRI特征性表现.方法 回顾性分析经手术病理证实的15例SNN的MRI征象,对病灶数目、形状、大小、部位、边界、平扫和增强后信号及强化方式进行评价.结果 病灶单发14例,另1例有2个病灶.平扫T1WI及T2WI各发现15和14个病灶,增强扫描发现16个病灶.14个病灶最大径≤3 cm.平扫T1WI病灶呈低信号5个,略低信号9个,1个呈等信号伴有周边低信号包膜及内部点状低信号.在T2WI病灶呈高信号5个,略高信号4个,略低信号3个,明显低信号2个,其中2个病灶内见点状或细线样极高信号.16例在增强扫描后各期均呈低信号,尤其在门静脉期及延迟期呈明显低信号,边界及形态显示清楚.12个病灶形状不规则,4个病灶呈圆形或卵圆形.增强后病灶内部均未见强化,3个病灶在门静脉期及延迟期可见细环状轻度强化的包膜.结论 SNN特征性MRI表现有助于与肝脏其他肿瘤鉴别.     

肝脏肺吸虫病变综合影像特征与病理对照分析

目的：研究肝脏肺吸虫病变的ＭＲＩ、ＣＴ和超声（ＵＳ）检查的影像特征及其病理组织学基础。材料与方法：回顾性分析了经病理证实的７例直径３ｃｍ以下肝脏肺吸虫病变的ＭＲＩ、ＣＴ和ＵＳ征象，并与病理结果进行了对照研究。结果：７例均为单发病变。ＵＳ均表现为低回声，彩色多普勒示病变内未见血流频谱；ＣＴ上６例呈低密度，１例为等密度，注射造影剂后病变内大部分无强化，周边轻度强化；ＭＲＩ上４例呈稍长Ｔ１、稍短Ｔ２信号，３例呈稍长Ｔ１、等和稍长Ｔ２信号；５例注射Ｇｄ－ＤＴＰＡ，病变周边均可见轻或中度强化，病变内大部分无强化。大体标本上病变呈边界清楚的灰黄或灰白色结节，４例呈多结节融合状，有部分或完整的纤维包裹；大体和组织切片示：病变内有含凝固坏死物的多房性小囊腔或穴道形成及较多的夏科雷登结晶和嗜酸粒细胞。结论：稍短Ｔ２信号是肝脏肺吸虫病变的重要征象。稍短Ｔ２信号的病理基础为凝固坏死。凝固坏死多呈稍长Ｔ１、稍短Ｔ２信号，也可呈稍长Ｔ１、稍长Ｔ２信号。     

Therapy evaluation of neuroendocrine liver metastases with contrast-enhanced MRI

Seventeen patients with neuroendocrine liver metastases, 14 of whom were treated with interferon, were examined with MRI before and after contrast administration to evaluate whether there were signal characteristics, differences in homogeneity and/or contrast enhancement patterns that indicated response to or failure of treatment. Of the treated patients 6 objectively responded to treatment (OR), 3 had progressive disease (PD) and 5 had stable disease (SD). A significant difference was found between the SD, untreated (UT) and OR groups of patients in terms of T1 (P = 0.01) and contrast enhancement (P = 0.02). The signal intensity ratio (SIR) in T2-weighted images between tumour and liver was significantly different (P = 0.05) between the OR and PD groups. This indicates that MRI may be used in therapy monitoring of patients with neuroendocrine metastases. Neuroendocrine metastases in the OR group had the same T1 and SIR values as those reported for haemangiomas, while patients in the PD, SD and UT groups had SIR values similar to those for colorectal metastases. Correspondence to: A. Elvin     

Diffuse liver disease: MRI with Gd-DTPA versus CT and ultrasound

Twenty-nine patients with diffuse liver disease were examined by ultrasound, CT and MRI. MRI was performed using T1- and T2-weighted spin-echo sequences as well as fast gradient-echo-sequences. The paramagnetic contrast agent Gd-DTPA was applied intravenously (0.1 mmol/kg). in patients with hepatitis, MRI could be used in guiding liver biopsies as inflammatory changes were clearly delineated. CT and ultrasound were superior to MRI in the detection of focal or diffuse fatty degeneration. On the other hand MRI was more helpful in differentiating fatty changes and neoplasm. In liver cirrhosis, fibrotic changes were most clearly demonstrated by MRI. In patients suffering from hemochromatosis MRI offers advantages over CT and ultrasound in the diagnosis and follow up due to the paramagnetic properties of iron, resulting in a reduction in signal intensity. In patients with Wilson's disease a characteristic pattern of parenchymal changes was seen. Administration of Gd- DTPA contributes additional information about perfusion conditions in the liver parenchyma, however this information was not of diagnostic relevance in the cases we studied. Correspondence to: T.J. Vogl     

Planning transarterial radioembolization of colorectal liver metastases with Yttrium 90 microspheres: evaluation of a sequential diagnostic approach using radiologic and nuclear medicine imaging techniques

The purpose of the study was to establish a diagnostic approach to the preparation of patients with colorectal liver metastases considered for transarterial radioembolization (RE). Twenty-two patients sequentially underwent computed tomography (CT; thorax/abdomen), magnetic resonance imaging (MRI; liver; hepatocyte-specific contrast), positron emission tomography (PET/PET-CT; F18-fluoro-desoxy-glucose), and angiography with perfusion scintigraphy [planar imaging; tomography with integrated CT (SPECT-CT)]. The algorithm was continued when no contraindication or alternative treatment option was found. The impact of each test on the therapy decision and RE management was recorded. Patient evaluation using CT revealed contraindications for RE in 4/22 patients (18%). Of the remaining 18 patients, 2 were excluded and 3 were assigned to locally ablative treatment based on MRI and PET results (28%). The remaining 13 patients entered the planning algorithm: SPECT-CT revealed gastrointestinal tracer accumulations in 4 (31%) patients [SPECT, 2 (15%)], making a modified application necessary. In five patients (38%), planar scintigraphy revealed relevant hepatopulmonary shunting. Therapy was finally administered to all 13 patients without therapy-related pulmonary or gastrointestinal morbidity. Each part of the diagnostic algorithm showed a relevant impact on patient management. The sequential approach appears to be suitable and keeps the number of unnecessary treatments and therapy risks to a minimum.     

Uncommon adrenal masses: CT and MRI features with histopathologic correlation

Adrenal glands are common sites of diseases. With dramatically increased use of computed tomography (CT) and magnetic resonance (MR) imaging, more and more uncommon adrenal masses have been detected incidentally at abdominal examinations performed for other purposes. In this article, uncommon adrenal masses are classified as cystic masses (endothelial cysts, epithelial cysts, parasitic cysts, and pseudocysts), solid masses (ganglioneuroma, ganglioneuroblastoma, extramedullary plasmacytoma (EMP), neurilemmoma, and lymphoma), fat-containing masses (myelolipoma, teratoma), and infectious masses (tuberculoma), and the imaging features of these uncommon masses are demonstrated. Although most of these lesions do not have specific imaging features, some fat-containing masses and cystic lesions present with characteristic appearances, such as myelolipoma, teratoma, and hydatid. Combination with histopathologic characteristic of these uncommon masses of adrenal gland, radiological features of these lesions on CT and MR imaging can be accurately understood with more confidences. Moreover, CT and MRI are highly accurate in localization of uncommon adrenal masses, and useful to guide surgical treatments.     

Response assessment of colorectal liver metastases with contrast enhanced CT/18F-FDG PET

Purpose

Evaluate the diagnostic performance of contrast enhanced CT/PET (ceCT/PET) in the response assessment of patients with colorectal cancer liver metastases.

Methods

33 ce CT/PET studies of 19 patients with colorectal liver metastases were prospectively evaluated. All of them, 13 (68.4%) were males and 6 (31.6%) females. Mean age and range were 63 [42–78]. All patients were treated with neoadjuvant chemotherapy. In all cases post-therapy diagnostic confirmation of liver lesions was obtained. A ce CT PET/was obtained 1 h after the injection of 370 MBq of 18F-FDG.Metabolic and morphologic studies were evaluated by two blinded nuclear physicians and radiologists respectively to assess the location, size and suspected diagnosis of lesions (benign or malignant). A combined assessment of both techniques was performed.The final diagnosis was established by histopathology or clinical/radiological follow-up greater than 6 months.

Results

A total of 120 liver lesions were identified, 115 were malignant and 5 benign.From the malignant lesions, 105 were identified with the ceCT, 44 with the PET and 109 with ceCT/PET. All of the benign lesions were correctly classified with any of the three imaging techniques.The sensitivity of PET, ceCT and ceCT/PET were of 38%, 91% and 95% respectively and the specificity was 100% in all three of the diagnostic studies.

Conclusion

Administration of intravenous contrast in the PET/CT is mandatory to evaluate treatment response rate of liver metastases due to the limitations of isolated metabolic images in these cases.     

CT与MRI低张力检查对消化道疾病的诊断价值

目的 :探讨低张力消化道CT与MR成像诊断胃肠道病变的临床价值。材料和方法 :用低张力检查诊断 42 8例消化道 ,并与 10 12例普通扫描进行了对比研究 ,病变者均经临床随访证实。　结果 :(1)低张组明显提高了解剖显示能力(P <0 0 5 ) ;(2 )低张组提高了消化道病灶的定位准确性 (CT提高 2 8 7%、MR提高 19 2 % ;P <0 0 1) ;(3 )低张组显著提高了消化管病灶的定性可靠程度 (P <0 0 1) ;(4 )有助于消化道毗邻结构的显示 (P <0 0 5 ) ;(5 )仅 9 6%有轻中度低张药物反应 ,无需处理。结论 :低张力消化道的CT与MR影像诊断具有重要意义 ,且安全、易行 ,应予肯定和推广。     

Preoperative evaluation of colorectal liver metastases: comparison between gadoxetic acid-enhanced 3.0-T MRI and contrast-enhanced MDCT with histopathological correlation

Objectives

The aim of this prospective study was to compare the diagnostic performance of 64-row MDCT and gadoxetic-acid-enhanced MRI at 3.0 T in patients with colorectal liver metastases in correlation with histopathological findings.

Methods

Lesions detected at MDCT and MRI were interpreted by three blinded readers and compared with histopathological workup as the term of reference. Two subgroups of lesions were additionally evaluated: (1) metastases smaller than 10 mm and (2) lesions in patients with and without steatosis of the liver, assessed histopathologically.

Results

Surgery and histopathological workup revealed 81 colorectal liver metastases in 35 patients and diffuse metastatic involvement in 3 patients. In a lesion-by-lesion analysis, significant sensitivity differences could only be found for reader 1 (P?=?0.035) and reader 3 (P?=?0.003). For segment-based evaluation, MRI was more sensitive only for reader 3 (P?=?0.012). The number of false-positive results ranged from 3 to 12 for MDCT and 8 to 11 for MRI evaluation. In the group of small lesions, the sensitivity differed significantly between both methods (P?=?0.003). In patients with hepatic steatosis, MRI showed a trend toward better performance than MDCT, but without statistical performance.

Conclusions

The 3.0-T MRI with liver-specific contrast agents is the preferred investigation in the preoperative setting, especially for the assessment of small colorectal liver metastases.

Key Points

? Potential surgical treatment requires accurate radiological assessment of colorectal liver metastases ? Magnetic resonance imaging with gadoxetic acid is the preferred imaging investigation. ? MRI is better than multidetector CT for detecting small liver metastases.