A comparison of arterial spin labeling perfusion MRI and DCE-MRI in human prostate cancer.

Perfusion MRI has the potential to provide pathophysiological biomarkers for the evaluating, staging and therapy monitoring of prostate cancer. The objective of this study was to explore the feasibility of noninvasive arterial spin labeling (ASL) to detect prostate cancer in the peripheral zone and to investigate the correlation between the blood flow (BF) measured by ASL and the pharmacokinetic parameters K(trans) (forward volume transfer constant), kep (reverse reflux rate constant between extracellular space and plasma) and ve (the fractional volume of extracellular space per unit volume of tissue) measured by dynamic contrast-enhanced (DCE) MRI in patients with prostate cancer. Forty-three consecutive patients (ages ranging from 49 to 86 years, with a median age of 74 years) with pathologically confirmed prostate cancer were recruited. An ASL scan with four different inversion times (TI = 1000, 1200, 1400 and 1600 ms) and a DCE-MRI scan were performed on a clinical 3.0 T GE scanner. BF, K(trans), kep and ve maps were calculated. In order to determine whether the BF values in the cancerous area were statistically different from those in the noncancerous area, an independent t-test was performed. Spearman's bivariate correlation was used to assess the relationship between BF and the pharmacokinetic parameters K(trans), kep and ve. The mean BF values in the cancerous areas (97.1 ± 30.7, 114.7 ± 28.7, 102.3 ± 22.5, 91.2 ± 24.2 ml/100 g/min, respectively, for TI = 1000, 1200, 1400, 1600 ms) were significantly higher (p < 0.01 for all cases) than those in the noncancerous regions (35.8 ± 12.5, 42.2 ± 13.7, 53.5 ± 19.1, 48.5 ± 13.5 ml/100 g/min, respectively). Significant positive correlations (p < 0.01 for all cases) between BF and the pharmacokinetic parameters K(trans), kep and ve were also observed for all four TI values (r = 0.671, 0.407, 0.666 for TI = 1000 ms; 0.713, 0.424, 0.698 for TI = 1200 ms; 0.604, 0.402, 0.595 for TI = 1400 ms; 0.605, 0.422, 0.548 for TI = 1600 ms). It can be seen that the quantitative ASL measurements show significant differences between cancerous and benign tissues, and exhibit strong to moderate correlations with the parameters obtained using DCE-MRI. These results show the promise of ASL as a noninvasive alternative to DCE-MRI.

Measuring diagnostic accuracy of imaging parameters in pelvic lipomatosis.

OBJECTIVES: To study whether the individual radiological findings can help predict diagnosis of pelvic lipomatosis (PL) or, specifically appreciate its progression. METHODS: Data from 32 clinically proven cases of PL and 25 controls were collected. Two reviewers were recruited for a blinded evaluation, image features were recorded in terms of: (1) bladder shape; (2) bladder-rectosigmoid morphological indexes including ratio of superior-inferior to anterior-posterior length of bladder (SI/AP), angle between anterior and posterior wall (AAP), relative length of posterior urethra (rLPU), angle between bladder and seminal vesicle (ABS) and rectosigmoid morphological index (RMI); (3) secondary complications. Results were evaluated by an unpaired t test and ROC analysis. RESULTS: The sensitivity and specificity were 40.6% and 100% for pear and banana-shaped bladder, 62.5% and 100% for SI/AP, 40.6% and 100% for AAP, 62.5% and 100% for ABS, 78.1% and 72% for rLPU, 59.4% and 96% for RMI, respectively. These radiological findings partially correlated with the severity of disease weighted by hydronephrosis and treatment grade. Image analysis demonstrated high prevalence of glandular cystitis (100%) and hydronephrosis (73.4%). CONCLUSION: We conclude that PL is a progressive disease involving multiple pelvic organs with high prevalence of intractable cystitis and hydronephrosis. The imaging characteristics can help predict diagnosis and, specifically appreciate progression.

Time course study on the effects of iodinated contrast medium on intrarenal water transport function using diffusion-weighted MRI.

PURPOSE: To assess the effects of intravenous-injected iodinated contrast medium (CM) on intrarenal water diffusion using noninvasive diffusion-weighted MRI (DW-MRI). MATERIALS AND METHODS: Ten New Zealand White rabbits were randomized to receive a 6 mL/kg body weight intravenous injection of clinically used iopamidol-370 (n = 7) or an equivalent amount of 0.9% physiological saline (n = 3). A sequential DW-MRI was performed to estimate the intrarenal apparent diffusion coefficient (ADC) at 24 h before and 1 h, 24 h, 48 h, and 72 h after administration. RESULTS: Iopamidol produced a progressive ADC reduction in inner stripes of the renal outer medulla (IS) by 13.92% (P = 0.05) at 1 h, 17.52% (P = 0.02) at 24 h, 20.23% (P = 0.01) at 48 h and 16.31% (P = 0.04) at 72 h after injection. Cortical ADC was decreased by 14.14% (P = 0.01) at 48 h and 14.12% (P = 0.01) at 72 h after injection. Iopamidol produced slight decrease of ADCs in outer stripes of the outer medulla (OS) and inner medulla (IM) of kidney but without statistical difference. In control group, no significant ADC changes was observed in each anatomic compartment due to saline injection (P > 0.05). CONCLUSION: As demonstrated by DW-MRI, intravenous iopamidol injection resulted in a successive reduction of intrarenal water diffusion, particularly in IS of kidney. This MR technique may be used as a noninvasive tool to perform a time course study of the pathogenesis associated with contrast-induced nephropathy (CIN).

Preliminary study of whole-body diffusion-weighted imaging in detecting pulmonary metastatic lesions from clear cell renal cell carcinoma: comparison with CT.

BACKGROUND: Whole-body diffusion-weighted imaging (DWI) has been widely used in detecting malignant metastases, including pulmonary metastases. PURPOSE: To evaluate the possible utility of whole-body DWI in detecting pulmonary metastases of patients with clear cell renal cell carcinoma (ccRCC) and compare the exact differences between MR and CT in detecting pulmonary lesions. MATERIAL AND METHODS: Whole-body DWI and chest CT examinations were performed on nine consecutive patients (8 men and 1 woman) with histologically confirmed ccRCC and possible metastatic lesions before chemotherapy. RESULTS: CT and MR demonstrated pulmonary metastases in seven patients and no metastatic lesions in two patients. The numbers of pulmonary metastases detected on CT, DWI-only, T1WI-only and DWI in combination with T1WI were 83, 35, 34 and 39, respectively. Metastases with a diameter above 1.0 cm could all be detected by DWI and a diameter above 0.7 cm could all be detected by DWI in combination with T1WI. Significant differences were obtained both for correlationship between diameter and detection rates of DWI and T1WI by using Spearman rank correlation analysis. CONCLUSION: Although MR cannot be considered a replacement for CT in pulmonary metastases from ccRCC, whole-body DWI, with the combination of T1 dual echo, might be helpful for the evaluation of tumor response to chemotherapy in the follow-up of patients when the diameter of the pulmonary metastases is over 1.0 cm.

Blood oxygen level-dependent MRI for the monitoring of neoadjuvant chemotherapy in breast carcinoma: initial experience.

PURPOSE: To determine the feasibility of using R2* map MRI for pretreatment diagnosis and monitoring of tumor response to neoadjuvant chemotherapy (NAC) in patients with breast cancer. MATERIAL AND METHODS: Twenty-eight women with breast cancer, as evidenced by pathology, underwent MR imaging prior to and after chemotherapy. All patients were examined by conventional MRI and R2* map imaging. Subjects were divided into major histological response (MHR) and non-major histological response (NMHR) groups. Mean R2* values of cancerous and normal glandular tissues were measured before and following NAC. Differences in R2* and ΔR2*% values between these two groups were compared with paired or independent t tests. The relationship between ΔR2*% and histological response was examined using Spearman's correlation test. RESULTS: Before NAC, the average R2* values in carcinoma were lower than in normal glandular tissue (P<.05). After two to four cycles of NAC, the R2* values in carcinoma were increased (P<.05 ), but this change was not significant in normal glandular tissue. After NAC, ΔR2*% was significantly higher in MHR as compared to NMHR (P<.05). The ΔR2*% correlated with the histological response (r=0.581, P<.01). CONCLUSION: In women undergoing NAC for breast cancer treatment, R2* and ΔR2*% appear to provide predictive information of tumor response which is probably associated with changes in tumor angiogenesis and tissue oxygenation. R2* map imaging of breasts may therefore be useful in monitoring tumor response to NAC.

[Small hepatocellular carcinoma in patients with hepatitis B-induced cirrhosis: a comparison between MRI and MDCT].

OBJECTIVE: To compare efficacy of plain and contrast enhancement MRI (1.5T or 3T) and dynamic contrast enhanced multidetector CT (MDCT, 16- or 64 -slice) for the detection of small hepatocellular carcinoma (HCC) in patients with hepatitis B-induced cirrhosis. METHODS: A total of 21 patients (18 men, 3 women; age range, 44-74 years) with 22 small HCC and liver cirrhosis were enrolled, all having undergone MDCT and MRI within one month. The diagnosis of small HCC was established at surgical resection (n=4), percutaneous biopsy (n=1), with positive tumor staining at intervention or from combined clinical data, typical imaging features and follow-up for a period of at least one year. Triple-phase or dual-phase dynamic contrast enhancement was performed on a 16- or 64-slice MDCT. MRI sequences included transverse T1-weighed images acquired as fast spoiled gradient (FSPGR) in-phase and out-of-phase dual-echo, transverse T2-weighed images with respiratory triggering acquired as fat-suppressed fast spin echo (FSE) or fast recovery fast spin echo (FRFSE), and breath-hold coronal T2-weighed images acquired as single shot fast spin echo (SSFSE) or fast imaging employing steady-state acquisition (FIESTA). CT and MRI observers independently analyzed each image in random order and marked each lesion detected with a score, ranking from 1 to 5 (1 definitely benign, 2 possibly benign, 3 undetermined, 4 possible HCC, and 5 definite HCC), then receiver operating characteristic (ROC) curve and Chi-square analysis were adopted to compare the efficacy for MDCT and MRI imaging. RESULTS: Although no significant difference was demonstrated at the comparison of sensitivity and specificity (sensitivity and specificity of MDCT: 70%, 50%; sensitivity and specificity of MRI 86.36%, 100%; sensitivity χ2=0.835, P=0.360; specificity χ2=1.379, P=0.240), the Az (area under the ROC curve) for MRI imaging (mean, 0.974) was much higher than that for MDCT (mean, 0.795) with significant difference (P<0.05). CONCLUSION: MRI imaging shows better diagnostic accuracy for the detection of small HCC in patients with hepatitis B-induced cirrhosis and is recommended to improve the detection and diagnosis.

Comparison of diffusion-weighted with T2-weighted Imaging for detection of small hepatocellular carcinoma in cirrhosis: preliminary quantitative study at 3-T.

RATIONALE AND OBJECTIVES: To compare diffusion-weighted (DW) with standard T2-weighted imaging for quantitative evaluation of small hepatocellular carcinoma (HCC) in cirrhosis. MATERIALS AND METHODS: Fourteen patients (all men; mean age, 58.6 years; age range, 45-69 years) with 22 small HCCs (<3 cm and >1 cm in diameter) in cirrhosis were included in the study. DW imaging with breath-hold single-shot echo planar imaging (b = 0, 800 seconds/mm(2)) and T2-weighted imaging with respiratory triggering fat-suppressed fast spin-echo sequence were performed on a 3-T magnetic resonance unit using an eight-channel torso phased-array coil. The signal intensity (SI) of HCC and liver were measured at workstation. Contrast-to-noise ratio (CNR), contrast ratio (CR, SI(lesion)/SI(liver)), and apparent diffusion coefficient (ADC) values were calculated. CNRs and CRs obtained with DW and T2-weighted images, and ADCs of HCC and liver were compared using nonparametric tests. RESULTS: Two lesions were excluded because of artifacts on DW images. Thus 20 lesions were analyzed. The CNRs obtained with T2-weighted images (27.12 + or - 21.12) were significantly higher (P = .02) than those with DW images (17.52 + or - 13.50). There were no significant difference between the CRs obtained with T2-weighted images (1.83 + or - 0.56) and DW images (2.01 + or - 0.67). There were no significant difference between the mean ADCs of HCC (1.22 x 10(-3) mm(2)/second + or - 0.24) and the cirrhotic liver (1.17 x 10(-3) mm(2)/second + or - 0.17), either. CONCLUSION: DW imaging with high b value was not superior to standard T2-weighted imaging in terms of lesion conspicuity of small HCC in cirrhosis.

[Analysis of the clinical information of 1,066 cases undergoing prostate magnetic resonance examination].

OBJECTIVE: To evaluate the variation of clinical data and referred purpose of prostate magnetic resonance (MR) examination in the past 12 years in Peking University First Hospital. METHODS: One thousand and sixty-six patients underwent prostate MR examination (1,296 exams) from May 1992 to Sept. 2004. The clinical data of the patients were retrospectively analyzed. The number of patients was counted and three groups were classified (diagnosing group, staging group and follow-up group) according to the purpose of prostate MR examination per year. For the diagnosing group, the clinical data of patient's age, symptom, level of serum prostate specific antigen (PSA), and the result of ultrasound or digital rectal examination (DRE) were evaluated. RESULTS: (1)The number of patients increased year by year in the past 12 years, and the majority of the increased patients required differential diagnosis. (2) Diagnosing group: the percentage of patients with the symptom of BPH increased year by year. The average level of serum PSA dropped and the percentage of patients with elevated PSA or with nodules detected by ultrasound or DRE referred for detection of prostate cancer or with the symptom of metastasis decreased. CONCLUSION: With the widespread screening of prostate cancer, more patients of early prostate carcinoma and non-tumoral lesion in prostate gland are examined by MR imaging.

[Localized Castleman disease with paraneoplastic pemphigus and pulmonary involvement: clinical features and histopathology].

OBJECTIVE: To investigate the clinical, histopathologic and CT features of localized Castleman disease complicated with paraneoplastic pemphigus (PNP) and pulmonary involvement. METHODS: The clinical, laboratory, histopathologic records and data of computed tomographic (CT) images of 4 patients of Castleman disease with PNP were reviewed. RESULTS: All of the four patients presented with PNP which was confirmed by pathological and immunological studies and also developed lung abnormalities, including bronchiolitis obliterans (n = 3), lung abscess (n = 1) and multiple lung infarction (n = 1), 2 to 5 months after the onset of PNP. Castleman's tumor, which was found incidentally during routine examination, manifested as a solitary and huge mass (5 to 14 cm in size) which markedly enhanced homogeneously on CT in the retroperitoneum (n = 3) and mediastinum (n = 1). Histologically, three cases were of hyaline-vascular type and the other one was of mixed type. Complete remission of PNP occurred 2 weeks to 8 months after surgical resection of the tumor. The condition of two patients with bronchiolitis obliterans failed to be improved. They had been presenting dyspnea and irritable cough 3 to 15 months after surgery. CONCLUSION: PNP and lung abnormalities are rare and severe complications of localized Castleman's disease. Early diagnosis and surgery are very important for prognosis.