Intravoxel incoherent motion diffusion-weighted imaging in assessing bladder cancer invasiveness and cell proliferation.

BACKGROUND: Nonmuscle-invasive bladder cancer (NMIBC, Stage T1 or lower) is treated with transurethral resection (TUR), while muscle-invasive bladder cancer (MIBC, Stage T2 or more) requires neoadjuvant chemotherapy before radical cystectomy. Hence, preoperative differentiation is vital. PURPOSE: To investigate whether intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) can differentiate NMIBC from MIBC and to assess whether there were correlations between IVIM parameters and the Ki-67 labeling index (LI). STUDY TYPE: Retrospective. SUBJECTS: Thirty-six patients diagnosed with bladder cancer confirmed by histopathological findings. FIELD STRENGTH/SEQUENCE: 3.0T magnetic resonance imaging (MRI) DWI with eight b-values ranging from 0 to 1000 s/mm2 . ASSESSMENT: Molecular diffusion coefficient (D), perfusion-related diffusion coefficient (D*), perfusion fraction (f), and apparent diffusion coefficient (ADC) were calculated by biexponential and monoexponential models fits, respectively. STATISTICAL TESTS: Comparisons were made between the MIBC and NMIBC group, and differences were analyzed by comparing the areas under the receiver-operating characteristic curves (AUCs). The correlations between these parameters and Ki-67 LI were assessed by Spearman's rank correlation analysis. RESULTS: The ADC and D value were significantly lower in patients with MIBC compared to those with NMIBC (P < 0.01). No significant (P > 0.05) differences were observed in D* and f. The AUC of D value (0.894) was significantly (P < 0.05) larger than the ADC value (0.786), with sensitivities and specificities of 95% and 87.5% (D) and 80% and 68.7% (ADC), respectively. In addition, the D and ADC values were significantly correlated with Ki-67 LI (r = -0.785, r = -0.643, respectively; both P < 0.01). DATA CONCLUSION: The D value obtained from IVIM exhibited better performance than conventional DWI for distinguishing NMIBC from MIBC and may serve as a potential imaging biomarker for bladder cancer invasion. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1054-1060.

Investigation of diffusion kurtosis imaging for discriminating tumors from inflammatory lesions after treatment for bladder cancer.

BACKGROUND: The bladder wall may thicken resulting from chronic inflammation after initial treatment (transurethral resection [TUR] or neoadjuvant chemotherapy), which may mimic the feature of recurrent or residual bladder tumors (RBT). Therefore, it is critical to discriminate RBT from benign lesions after initial treatment. PURPOSE: To investigate whether diffusion kurtosis imaging (DKI) could discriminate RBT from post-therapy bladder inflammatory lesions. STUDY TYPE: Retrospective. SUBJECTS: Fifty patients diagnosed with bladder cancer underwent TUR or received neoadjuvant chemotherapy. FIELD STRENGTH/SEQUENCE: 3.0T MRI/conventional T1 -weighted imaging (T1 WI), T2 WI, and diffusion-weighted imaging (DWI) with nine b-values ranging from 0-2000 s/mm2 . ASSESSMENT: Mean diffusion coefficients (MDa , MDb , and MDc ) and mean kurtosis values (MKa , MKb , and MKc ) were obtained from three different measurement methods. The region of interest (ROI) was placed 1) to encompass the entire portion of the thickening bladder wall or to portions that were the most restricted, with a b-value of 2) 2000 s/mm2 or 3) 1000 s/mm2 . STATISTICAL TESTS: The independent-samples t-test was used to compare the differences between RBT and the inflammatory group. Differences in DKI parameters were analyzed by comparing the areas under the receiver-operator characteristic curves (AUCs). RESULTS: In patients with RBT, the MD (MDa , MDb , MDc ) values were significantly lower and the MK (MKa , MKb , MKc ) values were significantly higher than those in patients in the inflammatory lesions group (all P < 0.01). The AUC of MKb (0.934) was significantly larger than those of MDb , MKa , and MKc (0.793, P < 0.05; 0.694, P < 0.01; 0.719, P < 0.01, respectively). DATA CONCLUSION: MK obtained from DKI provided better performance than conventional DWI in distinguishing RBT from inflammatory lesions after bladder cancer treatment. MK calculated with high b-values setting provided better performance in differentiation. LEVEL OF EVIDENCE: 1 Technical Efficacy Stage 3 J. Magn. Reson. Imaging 2017.

Quantitative assessment of angiographic perfusion reduction using color-coded digital subtraction angiography during transarterial chemoembolization.

PURPOSE: The aim of this study was to develop a quantitative measurement of perfusion reduction using color-coded digital subtraction angiography (ccDSA) to monitor intra-procedural arterial stasis during TACE. MATERIALS AND METHODS: A total number of 35 patients with hepatocellular carcinoma who had undergone TACE were enrolled into the study. Pre- and post-two-dimensional digital subtraction angiography scans were conducted with same protocol and post-processed with ccDSA prototype software. Time-contrast-intensity (CI[t]) curve was obtained by region-of-interest (ROI) measurement on the generated ccDSA image. Quantitative 2D perfusion parameters time to peak, area under the curve (AUC), maximum upslope, and contrast intensity peak (CI-Peak) derived from the ROI-based CI[t] curve for pre- and post-TACE were evaluated to assess the reduction of antegrade blood flow and tumor blush. Relationships between 2D perfusion parameters, subjective angiographic chemoembolization endpoint (SACE) scale, and clinical outcomes were analyzed. RESULTS: Area normalized AUC and CI-Peak revealed significant reduction after the TACE (P < 0.0001). AUCnorm decreased from pre-procedure of 0.867 ± 0.242 to 0.421 ± 0.171 (P < 0.001) after completion of TACE. CI-Peaknorm was 0.739 ± 0.221 before TACE and 0.421 ± 0.174 (P < 0.001) after TACE. Tumor blood supply time slowed down obviously after embolization. A perfusion reduction either from AUCnorm or CI-Peaknorm ranging from 30% to 40% was associated with SACE level III and a reduction ranging from 60% to 70% was equivalent to SACE level IV. For intermediate reduction (SACE level III), better tumor response was found after TACE rather than a higher reduction (SACE level IV). CONCLUSION: ccDSA application provides an objective approach to quantify the perfusion reduction and subjectively evaluate the arterial stasis of antegrade blood flow and tumor blush caused by TACE.

Chest X-ray and CT findings of early H7N9 avian influenza cases.

BACKGROUND: The H7N9 strain of bird flu is a new type of avian flu that was identified at the end of March 2013. The disease is concerning because most patients have become severely ill. PURPOSE: To study the X-ray and computed tomography (CT) findings of early H7N9 avian influenza cases. MATERIAL AND METHODS: Chest radiography and CT were performed in six patients with H7N9 avian influenza within 1-20 days after onset. The CT examinations included conventional spiral CT and high-resolution CT. The findings on the radiography and CT images were analyzed. RESULTS: Abnormal X-ray and CT findings were present in all of the patients. All of the cases had acute onset. In the early stage, the right lung was more commonly affected (particularly in the right upper and middle lobes). The lesions rapidly expanded to the entire lungs and were characterized primarily by ground-glass opacities (GGOs) combined with consolidation. Diffuse GGO was observed in all six cases (1 was symmetric, and 5 were non-symmetric). Local consolidation was found in four cases, and lobar consolidation was found in two cases. Normal lung tissue was observed between the lesions. Pleural thickening was common and was combined with pleural/pericardial effusion or mediastinal lymph node enlargement. Reticular changes, centrilobular nodules, and the tree-in-bud sign were observed in some cases, but reticular changes, bronchial wall thickening, and hyperinflation were not found. CONCLUSION: Radiological changes associated with both acute pneumonia and acute interstitial inflammation were observed in early H7N9 avian influenza cases. Serial chest X-rays were useful for the diagnosis and severity assessment of the disease. CT may provide a more accurate assessment of the lung pathology.

Usefulness of dual-energy computed tomography imaging in the differential diagnosis of sellar meningiomas and pituitary adenomas: preliminary report.

OBJECTIVE: To quantitatively assess the imaging characteristics of sellar lesion in dual-energy computed tomography (CT) imaging for differentiation of sellar meningiomas and pituitary adenomas during the arterial phase (AP) and venous phase (VP). MATERIALS AND METHODS: 51 patients with sellar/parasellar tumors (33 macroadenomas and 18 meningiomas) were examined with CT spectral imaging during the AP and the VP. Iodine concentrations were derived from iodine-based material-decomposition CT images and normalized to the iodine concentration in the aorta. The difference in Normalized iodine concentrations (NICs), HU curve slope (λHU), and mean CT values of lesions between the AP and VP were calculated. The two-sample t test was performed to compare quantitative parameters between sellar meningiomas and pituitary adenomas. RESULTS: NICs, λHU, and mean CT values in patients with sellar meningiomas differed significantly from those in patients with pituitary adenomas: Mean NICs were 43.52 mg/mL±1.35 versus 9.23 mg/mL ±2.44, respectively, during the AP and 52.13 mg/mL ±1.04 versus 24.37 mg/mL ±2.23 respectively, during the VP. λHU were -3.03±3.42 versus -0.53±0.23, respectively, during the AP and -2.96±0.41 versus -0.47±0.25, respectively, during the VP. Mean CT values were 193.63±2.08 versus 63.98±2.85, respectively, during the AP and 203.98±0.18 versus 77.66±0.91, respectively, during the VP. The combination of NIC and Mean CT value during VP had highest sensitivity (90.9%) and specificity (100%) among all phases. CONCLUSION: Quantitative dual-energy CT imaging has promising potential for diagnostic differentiation of sellar meningiomas and pituitary adenomas.

Quantitative iodine-based material decomposition images with spectral CT imaging for differentiating prostatic carcinoma from benign prostatic hyperplasia.

RATIONALE AND OBJECTIVES: To investigate the value of iodine-based material decomposition images produced via spectral computed tomography (CT) in differentiating prostate cancer (PCa) from benign prostate hyperplasia (BPH). MATERIALS AND METHODS: Fifty-six male patients underwent CT examination with spectral imaging during arterial phase (AP), venous phase (VP), and parenchymal phase (PP) of enhancement. Iodine concentrations of lesions were measured and normalized to that of the obturator internus muscle. Lesion CT values at 75 keV (corresponding to the energy of polychromatic images at 120 kVp) were measured and also normalized; their differences between AP and VP, VP and PP, and PP and AP were also obtained. The two-sample t-test was performed for comparisons. A receiver operating characteristic curve was generated to establish the threshold for normalized iodine concentration (NIC). RESULTS: Fifty-two peripheral lesions were found, which were confirmed by biopsy as 28 cases of PCa and 24 BPHs. The NICs of prostate cancers significantly differed from those of the BPHs: 2.38 ± 1.72 compared with 1.21 ± 0.72 in AP, respectively, and 2.67 ± 0.61 compared with 2.27 ± 0.77 in VP. Receiver operating characteristic analysis indicated that an NIC of 1.24 in the AP provided a sensitivity of 88% and a specificity of 71% for differentiating PCa from BPH. CONCLUSIONS: Spectral CT imaging enabled quantitative depiction of contrast medium uptake in prostatic lesions and improved sensitivity and specificity for differentiating PCa from BPH.

Low-dose hepatic computed tomography perfusion imaging and its preliminary study.

OBJECTIVE: Computed tomography perfusion imaging (CTPI) is a rapid and non-invasive functional imaging method that reflects hemodynamic changes of liver diseases. However, its large radiation dosage limits its clinical application. We aimed to evaluate the feasibility of low-dose CTPI in normal liver and its preliminary application in hepatocellular carcinoma (HCC). METHODS: CTPI was performed in 34 healthy volunteers randomly divided into three groups with different applications of tube current, including a conventional dose group, a median-dose group and a low-dose group. The perfusion parameters of each group were compared and a low-dose CTPI was performed in 13 patients with HCC. RESULTS: Relatively satisfying images and perfusion parameters of liver CTPI were acquired with the different tube currents. There were no significant differences between the parameters of the three groups (P>0.05). The effective dosage of conventional, median and low-dose liver CTPI were 19.62 mSv, 12.61 mSv, and 7.01 mSv, respectively. The radiation dosage of low-dose liver CTPI was reduced to 64.27% compared with that of the conventional group. The hepatic blood flow, hepatic blood volume and hepatic perfusion index of HCC were higher than background liver parenchyma and normal liver. CONCLUSIONS: Low-dose liver CTPI obtained similar perfusion parameters result to that of the conventional-dose, whereas the radiation dosage was reduced by 2/3. Low-dose liver CTPI can reflect the hemodynamic change of HCC. Low-dose liver CTPI has potential clinical value for diagnosis and differential diagnosis of liver diseases.

Pulmonary CT findings in relapsing polychondritis.

BACKGROUND: Relapsing polychondritis (RPC) is a rare rheumatic disease characterized by recurrent inflammation of cartilaginous structures, with airway involvement a major cause of morbidity and mortality. PURPOSE: To retrospectively evaluate airway and lung abnormalities in RPC with computed tomography (CT). MATERIAL AND METHODS: From January 2004 to May 2009, 21 patients with RPC (12 men, 9 women; 13-65 years old) underwent chest CT examinations. Two chest radiologists evaluated the CT images retrospectively. Abnormal findings, including airway stenosis, airway malacia, air trapping, and airway wall thickening with or without calcifications, were observed and noted. RESULTS: Major abnormal CT findings were observed in eight patients (38.1%), which included airway wall thickening (n=7), airway stenosis (n=6), airway malacia (n=6), airway wall calcification (n=8), and air trapping (n=3). Mediastinal lymph nodes were found in 12 patients. Lung infection was identified in four patients and interstitial lung disease in six patients. CONCLUSION: The CT findings in patients with RPC consisted mainly of airway wall thickening, airway stenosis, airway malacia, airway wall calcification, and air trapping.