Combined T2-weighted Imaging Research Articles

Detection of non-palpable breast cancer in asymptomatic women by using unenhanced diffusion-weighted and T2-weighted MR imaging: comparison with mammography and dynamic contrast-enhanced MR imaging

To compare the detectability of non-palpable breast cancer in asymptomatic women by using mammography (MMG), dynamic contrast-enhanced MR imaging (DCE-MRI) and unenhanced MR imaging with combined diffusion-weighted and T2-weighted images (DWI+T2WI). Forty-two lesions in 42 patients with non-palpable breast cancer in asymptomatic women were enrolled. For the reading test, we prepared a control including 13 normal and 8 benign cases. Each imaging set included biplane MMG, DCE-MRI and DWI+T2WI. Five readers were asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of cancer and the BI-RADS category. Confidence level results were used to construct receiver operating characteristic analysis. Sensitivity and specificity were calculated for each technique. DWI+T2WI showed higher observer performances (area under the curve, AUC, 0.73) and sensitivity (50%) for the detection of non-palpable breast cancer than MMG alone (AUC 0.64; sensitivity 40%) but lower than those of DCE-MRI (AUC 0.93; sensitivity 86%). A combination of MMG and DWI+T2WI exhibited higher sensitivity (69%) compared with that of MMG alone (40%). DWI+T2WI could be useful in screening breast cancer for patients who cannot receive contrast medium and could be used as a new screening technique for breast cancer.

Locally Recurrent Prostate Cancer after External Beam Radiation Therapy: Diagnostic Performance of 1.5-T Endorectal MR Imaging and MR Spectroscopic Imaging for Detection

To determine if performing magnetic resonance (MR) spectroscopic imaging, compared with performing T2-weighted MR imaging alone, improves the detection of locally recurrent prostate cancer after definitive external beam radiation therapy. This retrospective single-institution study was approved by the committee on human research, with a waiver of informed consent, and was compliant with HIPAA requirements. Sixty-four men who underwent endorectal MR imaging, MR spectroscopic imaging, and transrectal ultrasonographically guided biopsy for suspected local recurrence of prostate cancer after definitive external beam radiation therapy were retrospectively identified. Thirty-three patients had also received androgen therapy. Recurrent cancer was determined to be present or absent in the left and right sides of the prostate at T2-weighted MR imaging and MR spectroscopic imaging by a radiologist and a spectroscopist, respectively. Area under the receiver operating characteristic curve (A(Z)) was calculated for T2-weighted MR imaging alone and combined T2-weighted MR imaging and MR spectroscopic imaging by using generalized estimating equations and by using biopsy results as the reference standard. Recurrent prostate cancer was identified at biopsy in 37 (58%) of the 64 men. Recurrence was unilateral in 28 patients and bilateral in nine (total of 46 affected prostate sides). A(Z) analysis revealed that use of combined T2-weighted MR imaging and MR spectroscopic imaging (A(Z) = 0.79), as compared with T2-weighted MR imaging alone (A(Z) = 0.67), significantly improved the detection of local recurrence (P = .001). The addition of MR spectroscopic imaging to T2-weighted MR imaging significantly improves the diagnostic accuracy of endorectal MR imaging in the detection of locally recurrent prostate cancer after definitive external beam radiation therapy.

Prostate cancer detection with 3 T MRI: Comparison of diffusion‐weighted imaging and dynamic contrast‐enhanced MRI in combination with T2‐weighted imaging

To evaluate the diagnostic ability of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced imaging (DCEI) in combination with T2-weighted imaging (T2WI) for the detection of prostate cancer using 3 T magnetic resonance imaging (MRI) with a phased-array body coil. Fifty-three patients with elevated serum levels of prostate-specific antigen (PSA) were evaluated by T2WI, DWI, and DCEI prior to needle biopsy. The obtained data from T2WI alone (protocol A), a combination of T2WI and DWI (protocol B), a combination T2WI and DCEI (protocol C), and a combination of T2WI plus DWI and DCEI (protocol D) were subjected to receiver operating characteristic (ROC) curve analysis. The sensitivity, specificity, accuracy, and area under the ROC curve (Az) for region-based analysis were: 61%, 91%, 84%, and 0.8415, respectively, in protocol A; 76%, 94%, 90%, and 0.8931, respectively, in protocol B; 77%, 93%, 89%, and 0.8655, respectively, in protocol C; and 81%, 96%, 92%, and 0.8968, respectively in protocol D. ROC analysis revealed significant differences between protocols A and B (P = 0.0008) and between protocols A and D (P = 0.0004). In patients with elevated PSA levels the combination of T2WI, DWI, DCEI using 3 T MRI may be a reasonable approach for the detection of prostate cancer.

前立腺癌の局在診断におけるＭＲＩ拡散強調像の有用性の検討―前立腺全摘標本との比較

The objective of our study was to compare T2-weighted magnetic resonance imaging (T2WI), combined T2-weighted and dynamic imaging (Dynamic), and combined T2-weighted and diffusion-weighted imaging (DWI) in the identification of the site of prostate cancer. Before radical prostatectomy, 85 patients with prostate cancer underwent magnetic resonance imaging using a 1.5-T endorectal coil; we excluded 3 patients treated with neoadjuvant hormonal therapy. The sites of prostate cancer in 82 patients were predicted by T2WI alone, T2WI + Dynamic, and T2WI + DWI, and the results were compared with the step-section analysis of radical prostatectomy specimens. The peripheral zone (PZ) and the transition zone (TZ) of the prostate were divided into left and right halves. Only tumors with a diameter of more than 5 mm were considered significant. The sensitivity, specificity, positive predictive value (PPV), and the area under the receiver operating characteristic (ROC) curve (Az) for the prediction of the site of prostate cancer in the PZ of the prostate were as follows: 42%, 94%, 93%, and 0.76 for T2WI alone; 48%, 96%, 96%, and 0.78 for T2WI + Dynamic; and 50%, 96%, 96%, and 0.81 for T2WI + DWI. The sensitivity, specificity, PPV, and Az for the prediction of the site of prostate cancer in the TZ of the prostate were as follows: 31%, 92%, 76%, and 0.66 for T2WI alone; 46%, 82%, 67%, and 0.65 for T2WI + Dynamic; and 48%, 94%, 85%, and 0.71 for T2WI + DWI. The Az value for the prediction of prostate cancer in the PZ and those in the TZ of the prostate was the highest for the combined T2WI and DWI approach.

Prostate tumor volume measurement with combined T2-weighted imaging and diffusion-weighted MR: correlation with pathologic tumor volume

Prostate tumor volume measurement with combined T2-weighted imaging and diffusion-weighted MR: correlation with pathologic tumor volume

Prostate Tumor Volume Measurement with Combined T2-weighted Imaging and Diffusion-weighted MR: Correlation with Pathologic Tumor Volume

To retrospectively determine the accuracy of diffusion-weighted (DW) magnetic resonance (MR) imaging for identifying cancer in the prostate peripheral zone (PZ) and to assess the accuracy of tumor volume measurements made with T2-weighted imaging and combined T2-weighted and DW MR imaging by using surgical pathologic examination as the reference standard. The institutional review board issued a waiver of informed consent for this HIPAA-compliant study. Forty-two patients underwent endorectal MR at 1.5 T before undergoing radical prostatectomy for prostate cancer and had at least one PZ tumor larger than 0.1 cm(3) at surgical pathologic examination. On T2-weighted images, an experienced radiologist outlined suspected PZ tumors. Two apparent diffusion coefficient (ADC) cutoff values were identified by using the Youden index and published literature. Image cluster analysis was performed on voxels within the suspected tumor regions. Associations between volume measurements from imaging and from pathologic examination were assessed by using concordance correlation coefficients (CCCs). The sensitivity and specificity of ADCs for identifying malignant PZ voxels were calculated. In identifying malignant voxels, respective ADC cutoff values of 0.0014 and 0.0016 mm(2)/sec yielded sensitivity of 82% and 95% and specificity of 85% and 65%, respectively. Sixty PZ cancer lesions larger than 0.1 cm(3) were found at pathologic examination; 43 were detected by the radiologist. CCCs between imaging and pathologic tumor volume measurements were 0.36 for T2-weighted imaging, and 0.46 and 0.60 for combined T2-weighted and DW MR imaging with ADC cutoffs of 0.0014 and 0.0016 mm(2)/sec, respectively; the CCC of combined T2-weighted and DW MR imaging (ADC cutoff, 0.0016 mm(2)/sec) was significantly higher (P = .006) than that of T2-weighted imaging alone. Adding DW MR to T2-weighted imaging can significantly improve the accuracy of prostate PZ tumor volume measurement. http://radiology.rsnajnls.org/cgi/content/full/252/2/449/DC1.

Seminal vesicle invasion in prostate cancer: prediction with combined T2-weighted and diffusion-weighted MR imaging

The aim of this study was to evaluate the usefulness of diffusion-weighted imaging (DWI) in detecting seminal vesicle invasion (SVI). A total of 283 patients underwent conventional MRI and DWI before prostate cancer surgery. The apparent diffusion coefficient (ADC) values of all PCa foci, SVI and seminal vesicle were measured. T2 images alone and then T2 images combined with DWI were scored for the likelihood of SVI. The area under the receiver operating characteristic curve (AUC) was used to assess accuracy. Statistical significance was inferred at P < 0.05. On pathological analysis, 39 patients had SVI. The ADC values of SVI were significantly lower than those of SV. The AUC for T2-weighted imaging plus DW imaging (0.897) was significantly larger (P < 0.05) than that for T2-weighted imaging alone (0.779). T2 images combined with DWI shows significantly higher accuracy than T2-weighted imaging alone in the detection of SVI.

Combined use of T2-weighted and diffusion-weighted 3-T MR imaging for differentiating uterine sarcomas from benign leiomyomas

The objective of our study was to compare diffusion-weighted imaging (DWI) alone and DWI combined with T2-weighted MRI for the differentiation of uterine sarcomas from benign leiomyomas. T2-weighted imaging and DWI were performed in 103 patients with 103 myometrial tumours, including 8 uterine sarcomas and 95 benign leiomyomas on 3-T MR imaging. The signal intensity (SI) of the tumour on T2-weighted images was quantified as the tumour-myometrium contrast ratio (TCR) by using the following formula: (SI(tumour)-SI(myometrium))/SI(myometrium). The TCR or apparent diffusion coefficient (ADC) value alone and then the ADC value combined with T2-weighted imaging were evaluated for differentiation between sarcomas and leiomyomas. The mean ADC value of sarcomas was 0.86 +/- 0.11 x 10(-3) m(2)/s, which was significantly lower than that of leiomyomas 1.18 +/- 0.24 x 10(-3) m(2)/s; however, there was a substantial overlap. The mean TCR of sarcomas was 0.66 +/- 0.71, which was significantly higher than that of the leiomyomas, -0.37 +/- 0.34; however, again, there was a considerable overlap. When ADC was less than 1.05 x 10(-3) mm(2)/s and TCR was greater than 0 this condition was considered to confirm a sarcoma; a combination of ADC and TCR achieved a significant improvement without any overlap between sarcomas and leiomyomas (sensitivity 100%, specificity 100%). Our preliminary results indicate that combined DWI and T2-weighted MR imaging is better than DWI alone in the differentiation of uterine sarcomas from benign leiomyomas.

Usefulness of Diffusion-Weighted Imaging in the Localization of Prostate Cancer

Advances in high-precision radiation therapy techniques for patients with prostate cancer permit selective escalation of the radiation dose delivered to the dominant intraprostatic lesion and improve the therapeutic ratio. We evaluated the value of diffusion-weighted imaging (DWI) for dominant intraprostatic lesion assessment. The study population consisted of 23 patients with early prostate cancer. Before undergoing total prostatectomy, they were evaluated by means of magnetic resonance imaging, including DWI. T2-weighted imaging (T2WI) with and without DWI were retrospectively assessed by six independent observers. Imaging findings were compared with pathologic results from whole prostate specimens on a lesion-by-lesion basis. Pathologic study identified 43 lesions in 23 patients. On magnetic resonance imaging, the six observers correctly identified 11-22 of 43 lesions (sensitivity, 26-51%) on T2WI alone and 20-31 (sensitivity, 47-72%) on T2WI plus DWI. Positive predictive values were 42-73% on T2WI alone and 58-80% on T2WI plus DWI. For all observers, detection was higher on combined T2WI and DWI than on T2WI alone. Because the addition of DWI to T2WI improves the detectability of prostate cancer, DWI may offer a promising new approach for radiation therapy planning.

Prostate Cancer: Relationships between Postbiopsy Hemorrhage and Tumor Detectability at MR Diagnosis

To retrospectively evaluate the influence of postbiopsy hemorrhage on the accuracy of tumor detection at T2-weighted magnetic resonance (MR) imaging, dynamic contrast material-enhanced MR imaging, and diffusion-weighted (DW) MR imaging of prostate cancer, with histologic findings as the reference standard. The institutional review board approved this study and waived the requirement for informed consent. Forty male patients aged 62-84 years (mean age, 71 years) who had prostate cancer underwent MR imaging of the prostate gland after ultrasonographically (US) guided systematic 12-core-specimen biopsy. The mean time between biopsy and MR imaging was 24 days (range, 6-54 days). T1-weighted, T2-weighted, dynamic contrast-enhanced, and DW imaging examinations were performed at 1.5 T. The prostate was divided, according to the biopsy sites, into eight regions on the MR images. Three reviewers in consensus evaluated each region for hemorrhage and prostate cancer. Statistical evaluations were performed with Mann-Whitney U, Ryan, and Spearman rank correlation tests. Intraglandular hemorrhage was observed in 38 (95%) patients and significantly more often in the peripheral zone (PZ) than in the transition zone (TZ) (P < .001). Degree of hemorrhage did not correlate significantly (P = .536) with time between biopsy and MR imaging. The sensitivity, specificity, and accuracy of combined T2-weighted, dynamic contrast-enhanced, and DW imaging in the diagnosis of prostate cancer were 69%, 85%, and 78%, respectively. Sensitivity and specificity were lower for the TZ than for the PZ. Degree of hemorrhage was significantly lower in regions of positive biopsy findings than in regions of negative biopsy findings (P = .001) and correlated negatively with tumor size (P = .043). Interpretation of combined T2-weighted, dynamic contrast-enhanced, and DW MR image findings can yield reasonable diagnostic accuracy in both the PZ (80% [191 of 240 regions]) and the TZ (74% [59 of 80 regions]).

Prostate cancer detection: comparison of t2-weighted imaging, diffusion-weighted imaging, proton magnetic resonance spectroscopic imaging, and the three techniques combined

Magnetic resonance (MR) imaging has been established as the best imaging modality for the detection, localization, and staging of prostate cancer on account of its high resolution of soft tissue and the possibilities of multiplanar and multiparameter scanning. To evaluate T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), MR spectroscopy (MRS), and the combination of these three MR techniques in the diagnosis of prostate cancer, as correlated to histopathologic findings. MR imaging, including T2WI, DWI, and MRS, was performed at 1.5T with a body coil combined with a spine coil in 42 cases. Diagnosis was confirmed by histopathology through systematic transrectal prostate biopsy. Apparent diffusion coefficient (ADC) maps were obtained with two b values (0 and 1000 s/mm(2)). The metabolic maps of 3D-MRS imaging were analyzed for the ratio of (Cho+Cre)/Cit in each sextant. All cases were evaluated by T2WI, DWI, and MRS, and then by the three methods combined. The statistical indicators and the receiver operating characteristic (ROC) curve analysis of each method were compared to the results of histopathology obtained by transrectal prostate biopsy. 15 of 42 cases were confirmed to be cancerous, and 27 of 42 cases were noncancerous. All the 252 sextants were confirmed by biopsies, including 201 benign sextants and 51 malignant sextants. The sensitivity and the specificity for the detection of prostate cancer were 88.2% and 67.2% for T2WI, as the cutoff was 3; 82.4% and 81.6% for DWI, as the cutoff was 4; 84.3% and 98.0% for MRS, as the cutoff was 5; and 96.1% and 96.5% for the combined T2WI+DWI+MRS, as the cutoff was 4. In the ROC analysis, the correlative areas under the ROC curves (Az) were 0.848+/-0.030, 0.860+/-0.033, and 0.961+/-0.016 for T2WI, DWI, and MRS, respectively, and 0.978+/-0.009 for the combination of T2WI+DWI+MRS. The accuracy of the detection of prostate cancer is increased through a combination of the three techniques. Moreover, MRS demonstrated higher accuracy compared with T2WI or DWI.

Added diagnostic value of T2-weighted MR imaging to gadolinium-enhanced three-dimensional dynamic MR imaging for the detection of small hepatocellular carcinomas

Purpose To assess the added value of T2-weighted MRI to gadolinium-enhanced dynamic MRI for detection of HCCs. Materials and methods Two readers retrospectively analyzed MRIs of 115 patients with 131 HCCs (size; 0.6–2.0 cm) that had been diagnosed by histology ( n = 41) or imaging findings ( n = 90). Two separate blind image analyses of the gadolinium set and the combined T2-weighted imaging and gadolinium sets were performed. Diagnostic accuracy was evaluated using the alternative-free response receiver operating characteristic method with four-point scale. Sensitivity and positive predictive value were also calculated. Results For both observers, the Az values and sensitivities with the combined T2-weighed imaging and gadolinium set (mean Az 0.806, sensitivity 84.7) were significantly higher than those with the gadolinium set (mean Az 0.660, sensitivity 59.9) ( p < 0.05). The addition of T2-weighted imaging led to a change in diagnosis for 27 lesions by both observers, which at gadolinium set were assigned a confidence level of 1 or 2 but at additional reading of T2-weighted imaging were assigned a confidence level of 3 or 4. For the positive predictive values, each image set showed a similar value for each observer. Conclusion The addition of T2-weighted imaging to gadolinium-enhanced 3D dynamic imaging could be helpful in the detection of HCC by increasing reader confidence for HCCs with equivocal findings on gadolinium-enhanced MRIs.

Small hepatic lesions found on single‐phase helical CT in patients with malignancy: Diagnostic capability of breath‐hold, multisection fluid‐attenuated inversion‐recovery (FLAIR) MR imaging using a half‐fourier acquisition single‐shot turbo spin‐echo (HASTE) sequence

To evaluate the diagnostic capability of breath-hold, multisection fluid-attenuated inversion-recovery (FLAIR) imaging using a half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence in combination with T2-weighted fast spin-echo (FSE) magnetic resonance (MR) sequences for small hepatic lesions found on CT in patients with malignancy. This study included 48 patients with extrahepatic malignancy who underwent both CT and MR examinations. There were a total of 112 small hepatic lesions (73 cysts and 39 liver metastases, <2 cm in diameter) that showed low attenuation on enhanced CT. Three radiologists independently reviewed the CT and MR (FLAIR-HASTE and T2-weighted FSE) images and assigned a confidence level to their evaluation (cyst or metastasis) on a five-point scale. All three reviewers were significantly better able (P < 0.05) to differentiate small hepatic cyst from liver metastasis with combined FLAIR-HASTE and T2-weighted FSE images (Az values = 0.997-0.999) than with CT (0.917-0.932). The mean values of sensitivity, specificity, and accuracy were significantly higher (P < 0.001) for T2-weighted FSE with FLAIR-HASTE (96.6%, 96.8%, and 96.7%, respectively) than for CT (76.9%, 61.6%, and 67.3%, respectively). A confident diagnosis was rendered in 12 of 112 lesions (10.7%) on the basis of CT, and this rate increased to 83 of 112 (74.1%) on the basis of T2-weighted FSE and FLAIR-HASTE imaging. FLAIR-HASTE is considered to be an effective sequence for differentiating hepatic cysts from liver metastases without the use of a contrast agent. With FLAIR-HASTE one can confidently diagnose small hepatic lesions found on CT in patients with a malignancy.