Apparent Diffusion Coefficient Values of the Benign Central Zone of the Prostate: Comparison With Low- and High-Grade Prostate Cancer.

OBJECTIVE: The apparent diffusion coefficient (ADC) values for benign central zone (CZ) of the prostate were compared with ADC values of benign peripheral zone (PZ), benign transition zone (TZ), and prostate cancer, using histopathologic findings from radical prostatectomy as the reference standard. MATERIALS AND METHODS: The study included 27 patients with prostate cancer (mean [± SD] age, 60.0 ± 7.6 years) who had 3-T endorectal coil MRI of the prostate performed before undergoing prostatectomy with whole-mount histopathologic assessment. Mean ADC values were recorded from the ROI within the index tumor and within benign CZ, PZ, and TZ, with the use of histopathologic findings as the reference standard. ADC values of the groups were compared using paired t tests and ROC curve analysis. RESULTS: The ADC of benign CZ in the right (1138 ± 123 × 10(-6) mm(2)/s) and left (1166 ± 141 × 10(-6) mm(2)/s) lobes was not significantly different (p = 0.217). However, the ADC of benign CZ (1154 ± 129 × 10(-6) mm(2)/s) was significantly lower (p < 0.001) than the ADCs of benign PZ (1579 ± 197 × 10(-6) mm(2)/s) and benign TZ (1429 ± 180 × 10(-6) mm(2)/s). Although the ADC of index tumors (1042 ± 134 × 10(-6) mm(2)/s) was significantly lower (p = 0.002) than the ADC of benign CZ there was no significant difference (p = 0.225) between benign CZ and tumors with a Gleason score of 6 (1119 ± 87 × 10(-6) mm(2)/s). In 22.2% of patients (6/27), including five patients who had tumors with a Gleason score greater than 6, the ADC was lower in benign CZ than in the index tumor. The AUC of ADC for the differentiation of benign CZ from index tumors was 72.4% (sensitivity, 70.4%; specificity, 51.9%), and the AUC of ADC for differentiation from tumors with a Gleason score greater than 6 was 76.7% (sensitivity, 75.0%; specificity, 65.0%). CONCLUSION: The ADC of benign CZ is lower than the ADC of other zones of the prostate and overlaps with the ADC of prostate cancer tissue, including high-grade tumors. Awareness of this potential diagnostic pitfall is important to avoid misinterpreting the normal CZ as suspicious for tumor.

Detection of prostate cancer with multiparametric MRI (mpMRI): effect of dedicated reader education on accuracy and confidence of index and anterior cancer diagnosis.

PURPOSE: To evaluate the impact of dedicated reader education on accuracy/confidence of peripheral zone index cancer and anterior prostate cancer (PCa) diagnosis with mpMRI; secondary aim was to assess the ability of readers to differentiate low-grade cancer (Gleason 6 or below) from high-grade cancer (Gleason 7+). MATERIALS AND METHODS: Five blinded radiology fellows evaluated 31 total prostate mpMRIs in this IRB-approved, HIPAA-compliant, retrospective study for index lesion detection, confidence in lesion diagnosis (1-5 scale), and Gleason grade (Gleason 6 or lower vs. Gleason 7+). Following a dedicated education program, readers reinterpreted cases after a memory extinction period, blinded to initial reads. Reference standard was established combining whole mount histopathology with mpMRI findings by a board-certified radiologist with 5 years of prostate mpMRI experience. RESULTS: Index cancer detection: pre-education accuracy 74.2%; post-education accuracy 87.7% (p = 0.003). Confidence in index lesion diagnosis: pre-education 4.22 ± 1.04; post-education 3.75 ± 1.41 (p = 0.0004). Anterior PCa detection: pre-education accuracy 54.3%; post-education accuracy 94.3% (p = 0.001). Confidence in anterior PCa diagnosis: pre-education 3.22 ± 1.54; post-education 4.29 ± 0.83 (p = 0.0003). Gleason score accuracy: pre-education 54.8%; post-education 73.5% (p = 0.0005). CONCLUSIONS: A dedicated reader education program on PCa detection with mpMRI was associated with a statistically significant increase in diagnostic accuracy of index cancer and anterior cancer detection as well as Gleason grade identification as compared to pre-education values. This was also associated with a significant increase in reader diagnostic confidence. This suggests that substantial interobserver variability in mpMRI interpretation can potentially be reduced with a focus on education and that this can occur over a fellowship training year.

The state of prostate MRI in 2013.

Compared with earlier prostate MRI techniques that suffered from relatively poor sensitivity and specificity for detecting prostate cancer because of their reliance predominantly on morphology, multiparametric prostate MRI (mpMRI) in 2013 provides a wealth of functional information that has made possible vastly improved detection and characterization of prostate cancer. Our aims in this article are to describe the various imaging sequences that comprise the mpMRI exam, as well as to review current literature on the strengths/weaknesses of these sequences; to delineate strategies for standardizing interpretation and reporting of MRI results; and finally, to expound on the role that prostate MRI currently does and potentially can play in clinical practice.

Characterization of human atherosclerosis by optical coherence tomography.

BACKGROUND: High-resolution visualization of atherosclerotic plaque morphology may be essential for identifying coronary plaques that cause acute coronary events. Optical coherence tomography (OCT) is an intravascular imaging modality capable of providing cross-sectional images of tissue with a resolution of 10 micro m. To date, OCT imaging has not been investigated in sufficient detail to assess its accuracy for characterizing atherosclerotic plaques. The aim of this study was to establish objective OCT image criteria for atherosclerotic plaque characterization in vitro. METHODS AND RESULTS: OCT images of 357 (diseased) atherosclerotic arterial segments obtained at autopsy were correlated with histology. OCT image criteria for 3 types of plaque were formulated by analysis of a subset (n=50) of arterial segments. OCT images of fibrous plaques were characterized by homogeneous, signal-rich regions; fibrocalcific plaques by well-delineated, signal-poor regions with sharp borders; and lipid-rich plaques by signal-poor regions with diffuse borders. Independent validation of these criteria by 2 OCT readers for the remaining segments (n=307) demonstrated a sensitivity and specificity ranging from 71% to 79% and 97% to 98% for fibrous plaques, 95% to 96% and 97% for fibrocalcific plaques, and 90% to 94% and 90% to 92% for lipid-rich plaques, respectively (overall agreement, kappa=0.83 to 0.84). The interobserver and intraobserver reliabilities of OCT assessment were high (kappa values of 0.88 and 0.91, respectively). CONCLUSIONS: Objective OCT criteria are highly sensitive and specific for characterizing different types of atherosclerotic plaques. These results represent an important step in validating this new intravascular imaging modality and will provide a basis for the interpretation of intracoronary OCT images obtained from patients.

Quantification of macrophage content in atherosclerotic plaques by optical coherence tomography.

BACKGROUND: Macrophage degradation of fibrous cap matrix is an important contributor to atherosclerotic plaque instability. An imaging technology capable of identifying macrophages in patients could provide valuable information for assessing plaque vulnerability. Optical coherence tomography (OCT) is a new intravascular imaging modality that allows cross-sectional imaging of tissue with a resolution of approximately 10 micro m. The aim of this study was to investigate the use of OCT for identifying macrophages in fibrous caps. METHODS AND RESULTS: OCT images of 26 lipid-rich atherosclerotic arterial segments obtained at autopsy were correlated with histology. Cap macrophage density was quantified morphometrically by immunoperoxidase staining with CD68 and smooth muscle actin and compared with the standard deviation of the OCT signal intensity at corresponding locations. There was a high degree of positive correlation between OCT and histological measurements of fibrous cap macrophage density (r=0.84, P<0.0001) and a negative correlation between OCT and histological measurements of smooth muscle actin density (r=-0.56, P<0.005). A range of OCT signal standard deviation thresholds (6.15% to 6.35%) yielded 100% sensitivity and specificity for identifying caps containing >10% CD68 staining. CONCLUSIONS: The high contrast and resolution of OCT enables the quantification of macrophages within fibrous caps. The unique capabilities of OCT for fibrous cap characterization suggest that this technology may be well suited for identifying vulnerable plaques in patients.

Partial splenic embolization for cancer patients with thrombocytopenia requiring systemic chemotherapy.

BACKGROUND: Partial splenic embolization (PSE) has been used to improve hematologic parameters related to hypersplenism. The purpose of this study was to review our institutional experience with PSE for cancer patients with thrombocytopenia because of splenic sequestration precluding the administration of systemic therapy (ST). METHODS: A retrospective review of cancer patients undergoing PSE was undertaken. Twenty-eight patients underwent PSE to correct thrombocytopenia to facilitate the initiation or resumption of ST. Primary and secondary endpoints of the current study included a platelet count increase > 150 K/UL and the initiation of ST, respectively. Periprocedural laboratory values and adverse events were recorded. RESULTS: Thirty PSEs were performed in 28 patients. Two patients underwent repeat PSE because of recurrent thrombocytopenia after the successful initiation of ST. For procedures with adequate follow-up, primary and secondary endpoints were achieved in 96.3% (26 of 27 patients) and 95.7% (22 of 23 patients) of patients, respectively. The mean platelet count was 81 K/UL immediately before PSE and peaked at 293 K/UL after PSE. For 23 patients with frequent laboratory follow-up, the mean time to a platelet count > 150 K/UL was 10 days. The mean hospital stay was 4.5 days. Postprocedure abdominal pain occurred in all patients. Fever was documented in 16 patients and pulmonary consolidation/atelectasis or effusion was documented in 10 patients; 9 patients received empiric antibiotic coverage. The median overall survival was 9.40 months (95% confidence interval, 8.2-10.7 months) among the 28 patients after PSE. CONCLUSIONS: PSE is a safe and effective means of managing thrombocytopenia secondary to hypersplenism to facilitate the administration of ST in patients with cancer.

Focal and multi-focal plaque macrophage distributions in patients with acute and stable presentations of coronary artery disease.

OBJECTIVES: This study was designed to utilize optical coherence tomography (OCT) images of coronary atherosclerotic plaque macrophages to investigate the relationship between macrophage distributions and clinical syndrome. BACKGROUND: The relative significance of focal macrophage infiltration and generalized coronary inflammation for predicting acute coronary events is a currently a source of considerable controversy in cardiology. Lack of a high-resolution cross-sectional imaging modality has limited macrophage evaluation in vivo. METHODS: Intracoronary OCT imaging was performed at culprit and non-culprit plaques in patients presenting with stable angina pectoris, unstable angina pectoris,and ST-segment elevation myocardial infarction. Macrophage densities were quantified from these images and analyzed with respect to the clinical presentations of the patients under investigation. RESULTS: A significantly greater macrophage density was found in unstable patients, both for fibrous and lipid-rich plaques (p = 0.025 and p = 0.002, respectively). Within each patient, the macrophage densities at culprit and non-culprit lesions correlated significantly (r = 0.66, y = 0.88x + 0.43, p = 0.01). Sites of plaque rupture demonstrated a greater macrophage density than non-ruptured sites (6.95 +/- 1.60%, 5.29 +/- 1.17%; p = 0.002). Surface macrophage infiltration was a stronger predictor of unstable clinical presentation than subsurface infiltration for culprit lesions (p = 0.035) but not for remote lesions (p = 0.80). CONCLUSIONS: Our results demonstrate that increases in both multi-focal and focal macrophage densities are highly correlated with symptom severity. By providing a means of detecting increases in plaque macrophage content before an acute event, this technique may aid in determining prognosis and guiding preventive therapy.