Differentiation between fat-poor angiomyolipoma and clear cell renal cell carcinoma: qualitative and quantitative analysis using arterial spin labeling MR imaging.

PURPOSE: To assess the diagnostic effectiveness of arterial spin labeling (ASL) MR imaging in differentiating fat-poor AML from clear cell renal cell carcinoma (ccRCC). METHODS: In this prospective study, 29 ccRCC patients and 9 fat-poor AML patients underwent routine anatomical MRI and ASL at 3T before surgery after signing written informed consent form. For each tumor, tumor blood flow (TBF) was measured in a region of interest (ROI) which was positioned to outline the edge of the target lesions on ASL perfusion maps. Additionally, the mean TBF values were obtained by standardizing the TBF using a blood flow measurement in the reference ROI. Moreover, a cluster containing more than 10 voxels was chosen from the renal cortex and medulla area in normal contralateral kidney as a reference ROI to calculate tumor-to-cortex ratio and tumor-to-medulla ratio. Independent sample t test was used to examine the alteration among the groups of fat-poor AML and ccRCC. ASL images were together analyzed by two radiologists to assess the following characteristics of the renal mass: predominant SI in the tumor on ASL images was lower than, as same as, or higher than SI of the cortex. For qualitative variables, Fisher's exact test was employed to compare the proportions of these two groups. The sensitivity, specificity ,and accuracy required for discrimination of fat-poor AML from ccRCC were quantified using receiver operating characteristic (ROC) curve. The corresponding optimal cutoff value was obtained for each parameter as well. RESULTS: The TBF value was significantly higher in ccRCC group than that in fat-poor AML (270.49 ± 78.88 ml/100 g/min vs. 146.68 ± 47.21 ml/100 g/min; P < 0.01). Both tumor-to-cortex and tumor-to-medulla ratios were notably higher in ccRCC group compared with those in fat-poor AML group (1.22 ± 0.26 vs. 0.74 ± 0.14, 3.13 ± 0.94 vs. 1.77 ± 0.55; P < 0.05). The values of area under the ROC curve (AUC) for TBF, tumor-to-cortex ratio, and tumor-to-medulla ratio were 0.931, 0.964, and 0.900, respectively. No significant difference in AUC values among these three measurements was observed. For qualitative variables, the SI of fat-poor AML was equal to or slightly lower than that of renal medulla and the SI of ccRCC was found to be higher than renal cortex in ASL. CONCLUSION: ASL MRI performs well in differentiating fat-poor AML from ccRCC in both qualitative and quantitative analyses.

Quantitative Evaluation of Intravoxel Incoherent Motion and Diffusion Kurtosis Imaging in Assessment of Pathological Grade of Clear Cell Renal Cell Carcinoma.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic value of intravoxel incoherent motion and diffusion kurtosis imaging parameters for clear cell renal cell carcinoma (ccRCC) grading. MATERIALS AND METHODS: A total of 60 patients with pathologically proven ccRCC who underwent intravoxel incoherent motion and diffusion kurtosis imaging were retrospectively evaluated. The standard apparent diffusion coefficient (ADC), true diffusivity (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), mean kurtosis (MK), and mean diffusivity (MD) maps were calculated and compared between high-grade and low-grade ccRCC using Mann-Whitney U test. Receiver-operating characteristic analysis was performed for all parameters. RESULTS: ADC, D and MD values were significantly lower for high-grade ccRCC compared to low-grade ccRCC (p < 0.05). MK values were significantly higher in high-grade ccRCC compared to low-grade ccRCC (p < 0.05). However, D* and f were not significantly difference between the two groups (p > 0.05). MD had the largest area under the curve (AUC = 0.888), followed by ADC (AUC = 0.796), D (AUC = 0.780), MK (AUC = 0.736), f (AUC = 0.582), and D*(AUC = 0.533). CONCLUSION: Diffusion-related parameters (D, ADC, MD, and MK) were able to significantly distinguish between low- and high-grade ccRCC. However, perfusion-related parameters (D* and f) were unable to separate high- and low-grade ccRCC. MD may be the most promising parameter for grading ccRCC in the clinic.

Imaging of mixed epithelial and stromal tumor of the kidney: A case report and review of the literature.

BACKGROUND: Mixed epithelial and stromal tumors of the kidney (MESTKs) are a rare entity (about a hundred cases reported). They occur almost exclusively in postmenopausal women, with only seven cases reported in men. As this entity is very rare, little is known on its imaging features, especially magnetic resonance imaging (MRI) findings. In women, at MRI, the cystic component shows T1 hypointensity and T2 hyperintensity, while the solid component shows T1 hyperintensity and T2 hypointensity. CASE SUMMARY: We report the computed tomography (CT) and MRI findings of MESTK in a 19-year-old male adolescent. To our knowledge, this case report is the first report of MRI findings of MESTK in male adolescents. The patient was admitted to Subei People's Hospital (Jiangsu Province, China) in July 2017 after a renal mass on the left side was detected by ultrasound during a clinical examination. Blood tests were all normal. Non-enhanced CT showed a round, well-circumscribed complex mass, approximately 45 mm × 40 mm in size. MRI revealed a clear well-circumscribed mass with a mixed arrangement of solid and cystic components. On T2 weighted images, some hypointensities were found in the solid areas. After contrast enhancement, moderate or mild enhancement was found in the solid component, which increased with time. A radical left nephrectomy was performed. The pathology analysis revealed a mixed epithelial and stromal tumor. The patient had no imaging findings of recurrence or metastasis at 12 months following surgery. CONCLUSION: The possibility of MESTK should be considered in male adolescents. MRI can provide useful information for the preoperative diagnosis.

Comparative study of intestinal tuberculosis and primary small intestinal lymphoma.

AIM: To characterize the clinical, radiological, endoscopic and pathological features of intestinal tuberculosis (ITB) and primary small intestinal lymphoma (PSIL). METHODS: This was a retrospective study from February 2005 to October 2012 of patients with a diagnosis of ITB (n = 41) or PSIL (n = 37). All patients with ITB or PSIL underwent computed tomography (CT) and pathological examination. Thirty-five patients with ITB and 32 patients with PSIL underwent endoscopy. These patients were followed for a further 18 mo to ascertain that the diagnosis had not changed. Clinical, endoscopic, CT and pathological features were compared between ITB and PSIL patients. RESULTS: Night sweating, fever, pulmonary TB and ascites were discovered significantly more often in ITB than in PSIL patients (P < 0.05), however, abdominal mass, hematochezia and intestinal perforation were found significantly more frequently in PSIL than in ITB patients (P < 0.05). Ring-like and rodent-like ulcers occurred significantly more often in ITB than in PSIL patients (P < 0.05), however, enterorrhagia and raised lesions were significantly more frequent in PSIL than in ITB patients (P < 0.05). The rate of granuloma was significantly higher in ITB than in PSIL patients (87.8% vs 13.5%, χ(2) = 43.050, P < 0.05), and the incidence of confluent granulomas with caseous necrosis was significantly higher in ITB than in PSIL patients (47.2% vs 0.0%, χ(2) = 4.034, P < 0.05). Multi-segmental lesions, mural stratification, mural gas sign, and intestinal stricture were more frequent in ITB than in PSIL patients (P < 0.05), however, a single-layer thickening of bowel wall, single segmental lesions, and intussusception were more common in PSIL than in ITB patients (P < 0.05). Necrotic lymph nodes, comb sign and inflammatory mass were more frequent in ITB than in PSIL patients (P < 0.05). The bowel wall enhancement in ITB patients was greater than that in PSIL patients (P < 0.05), while the thickening and lymph node enlargement in PSIL patients were higher than those in ITB patients (P < 0.05). CONCLUSION: Combined evaluation of clinical, radiological, endoscopic and pathological features is the key to differentiation between ITB and PSIL.

[Assessment of the diagnostic value of CT and X-ray enterography for small intestinal Crohn disease].

OBJECTIVE: To investigate the value of CT and X-ray enterography in the diagnosis of small intestinal Crohn disease(CD). METHODS: Data of 39 CD cases confirmed by surgery and pathology who underwent CT and X-ray enterography were analyzed retrospectively. All the patients had complete CT data, 28 cases had X-ray intestinal barium meal data, and 18 had sinus tract enterography. RESULTS: CT enterography showed mural thickening(>4 mm) in 34(87.2%) patients, mural gas in 7(17.9%), mural edema in 7(17.9%), mural fat in 4(10.3%), increased enhancement of bowel wall(>10 HU) in 37(94.9%), multiple segmental lesions in 33(84.6%), single segmental lesions in 6(15.4%), mesenteric lymphadenopathy(>5 mm) in 13(33.3%), vascular bundle thickening in 9(23.1%), cellulitis in 12(30.8%), peritoneal abscess in 10(25.6%), phlegmon in 8(20.5%), incomplete intestinal obstruction in 14(35.9%), seroperitoneum in 22(56.4%), and fistulization in 4(10.3%). CT enterography did not demonstrate the change of mucosa such as strip ulcer or cobblestone. Among the 28 cases of small bowel X-ray enterography, 23 cases(82.1%) presented with multiple segmental lesions, 5(17.9%) with single segmental lesions, 18(64.3%) with strip ulcer, 16(57.1%) with cobblestones, 4(14.3%) with intestinal fistula, while no bowel wall and extraintestinal complication of CD disease was observed. Among the 18 cases of sinus tract enterography, 13 cases (72.2%) presented with intestinal fistula, 12(66.7%) with peritoneal abscess, 8(44.4%) with sinus tract. CONCLUSIONS: CT enterography can demonstrate exactly the diseased bowel wall and extraintestinal complication of CD disease, which is important to evaluate the extent of CD and guide the treatment, however strip ulcer and cobblestone sign cannot be demonstrated. The X-ray enterography is available to demonstrate the characteristic changes of CD such as trip ulcers and cobblestones, but is difficult to show the bowel wall and extraintestinal inflammatory mass and abscesses. The sinus tract enterography is easy to demonstrate the intestinal fistula and intra-abdominal abscess. Combination of these methods is more beneficial to guild the diagnosis and treatment.

[Differential diagnosis of intestinal tuberculosis and primary small intestinal lymphoma using endoscopy and computerized tomography].

OBJECTIVE: To analyze the characteristics of intestinal tuberculosis(ITB) and primary small intestinal lymphoma(PSIL) in order to provide clue for the differential diagnosis. METHODS: Data of 24 cases of ITB and 23 cases of PSIL confirmed by surgery and pathology were retrospectively analyzed. The clinical features, endoscopic and CT scan were compared. All the patients had complete clinical and CT data. Twenty cases of ITB and 20 PSIL had complete endoscopic data. RESULTS: ITB was associated with significantly higher proportion of patients with fever(58.3% vs. 4.3%), night sweating(50.0% vs. 8.6%), pulmonary tuberculosis(54.2% vs. 4.3%) and ascites(54.2% vs. 21.7%) than PSIL(all P<0.05), and lower proportion of patients with abdominal mass (4.2% vs. 39.1%), hematochezia (8.3% vs. 47.8%), and perforation (0 vs. 39.1%)(all P<0.01). Endoscopic examination showed circumferential ulcer and rodent ulcer in 40% and 35% of the patients with ITB, and massive lesion and polypoid lesion in 55% of the patients with PSIL(P<0.05). Multi-segmental lesions, layered thickening, pneumatosis intestinalis, edematous ring, bowel lumen narrowing, hollow lymph nodes, and comb sign were more common in ITB(P<0.05), while single segmental lesions, eccentric thickening, and intussusception were more common in PSIL(P<0.05). The enhancement of intestinal wall of ITB were higher than that of PSIL(P<0.05), while the thickening and lymph nodes enlargement of PSIL were higher than that of ITB(P<0.05). CONCLUSION: The clinical characteristics differ between ITB and PSIL and the differential diagnosis can be made by combining endoscopy and CT.

[Multi-slice computed tomography diagnosis of collecting duct carcinoma].

OBJECTIVE: To explore the diagnostic features of collecting duct carcinoma (CDC). METHODS: A total of 7 CDC patients were retrospectively examined by multi-slice computed tomography (MSCT). The relevant diagnostic parameters were assessed. RESULTS: All lesions were located in renal medulla. Among them, infiltrations extended to renal calyx (n = 3) and cortex (n = 5). There were indistinct boundaries (capsule sign) on enhanced phase (n = 6) and pre-capsule (n = 1). On non-enhanced CT, CDC attenuation was greater than normal renal cortex or medulla (43.8 ± 5.3 vs 37.6 ± 5.1 or 32.6 ± 4.1, P < 0.05). The degree of enhancement was less than normal renal cortex and medulla during all enhanced phases (P < 0.05 or 0.01). Excellent consistency existed between CT appearances of CDC and pathological characteristics. CONCLUSION: Dynamic contrast enhanced-CT can show distinct imaging features of CDC correlated with pathological characteristics so as to allow a better differential diagnosis.