Faculty Bibliography

OBJECTIVES: We compared the image quality and diagnostic performance of 2 fat-suppression methods for black-blood T2-weighted fast spin-echo (FSE), which are as follows: (a) short T1 inversion recovery (STIR; FSE-STIR) and (b) spectral adiabatic inversion recovery (SPAIR; FSE-SPAIR), for detection of acute myocardial injury. BACKGROUND: Edema-sensitive T2-weighted FSE cardiac magnetic resonance (CMR) imaging is useful in detecting acute myocardial injury but may experience reduced myocardial signal and signal dropout. The SPAIR pulse aims to eliminate artifacts associated with the STIR pulse. MATERIALS AND METHODS: A total of 65 consecutive patients referred for CMR evaluation of myocardial structure and function underwent FSE-STIR and FSE-SPAIR, in addition to cine and late gadolinium enhancement (LGE) CMR. T2-weighted FSE images were independently evaluated by 2 readers for image quality and artifacts (Likert scale of 1-5; best-worst) and presence of increased myocardial signal suggestive of edema. In addition, clinical CMR interpretation, incorporating all CMR sequences available, was recorded for comparison. Diagnostic performance of each T2-weighted sequence was measured using recent (<30 days) troponin elevation greater than 2 times the upper limit of normal as the reference standard for acute myocardial injury. RESULTS: Of the 65 patients, there were 21 (32%) with acute myocardial injury. Image quality and artifact scores were significantly better with FSE-SPAIR compared with FSE-STIR (2.15 vs 2.68, P < 0.01; 2.62 vs 3.05, P < 0.01, respectively). The sensitivity, specificity, positive predictive value, and negative predictive value for acute myocardial injury were as follows: 29%, 93%, 67%, and 73% for FSE-SPAIR; 38%, 91%, 67%, and 75% for FSE-STIR; 71%, 98%, 94%, and 88% for clinical interpretation including LGE, T2, and wall motion. There was a statistically significant difference in sensitivity between the clinical interpretation and each of the T2-weighted sequences but not between each T2-weighted sequence. CONCLUSIONS: Although FSE-SPAIR demonstrated significantly improved image quality and decreased artifacts, isolated interpretations of each T2-weighted technique demonstrated high specificity but overall low sensitivity for the detection of myocardial injury, with no difference in accuracy between the techniques. However, real-world interpretation in combination with cine and LGE CMR methods significantly improves the overall sensitivity and diagnostic performance.

OBJECTIVE: The objectives of this study were to develop a new method for free-breathing contrast-enhanced multiphase liver magnetic resonance imaging (MRI) using a combination of compressed sensing, parallel imaging, and radial k-space sampling and to demonstrate the feasibility of this method by performing image quality comparison with breath-hold cartesian T1-weighted (conventional) postcontrast acquisitions in healthy participants. MATERIALS AND METHODS: This Health Insurance Portability and Accountability Act-compliant prospective study received approval from the institutional review board. Eight participants underwent 3 separate contrast-enhanced fat-saturated T1-weighted gradient-echo MRI examinations with matching imaging parameters: conventional breath-hold examination with cartesian k-space sampling volumetric interpolate breath hold examination (BH-VIBE) and free-breathing acquisitions with interleaved angle-bisection and continuous golden-angle radial sampling schemes. Interleaved angle-bisection and golden-angle data from each 100 consecutive spokes were reconstructed using a combination of compressed sensing and parallel imaging (interleaved-angle radial sparse parallel [IARASP] and golden-angle radial sparse parallel [GRASP]) to generate multiple postcontrast phases.Arterial- and venous-phase BH-VIBE, IARASP, and GRASP reconstructions were evaluated by 2 radiologists in a blinded fashion. The readers independently assessed quality of enhancement (QE), overall image quality (IQ), and other parameters of image quality on a 5-point scale, with the highest score indicating the most desirable examination. Mixed model analysis of variance was used to compare each measure of image quality. RESULTS: Images of BH-VIBE and GRASP had significantly higher QE and IQ values compared with IARASP for both phases (P < 0.05). The differences in QE between BH-VIBE and GRASP for the arterial and venous phases were not significant (P > 0.05). Although GRASP had lower IQ score compared with BH-VIBE for the arterial (3.9 vs 4.8; P < 0.0001) and venous (4.2 vs 4.8; P = 0.005) phases, GRASP received IQ scores of 3 or more in all participants, which was consistent with acceptable or better diagnostic image quality. CONCLUSION: Contrast-enhanced multiphase liver MRI of diagnostic quality can be performed during free breathing using a combination of compressed sensing, parallel imaging, and golden-angle radial sampling.

Purpose: Various endpoints of embolization have been advocated by investigators during uterine artery embolization (UAE) for the treatment of symptomatic uterine fibroids. Described endpoints are based on angiographic appearance. Our intent is to objectively define a non-imaging endpoint of embolization in patients undergoing UAE. Materials and Methods: 55 consecutive patients with symptomatic uterine fibroids underwent UAE using an outer 5- and inner 3-Fr. catheters. Prior to and following embolization, systolic, diastolic, and mean intra-arterial blood pressures (BP) were measured within the ipsilateral internal iliac and the uterine (UA) arteries. For uniformity, the fluoroscopic endpoint was defined as the clearing of contrast within the main UA in or after 5 cardiac cycles. The mean+/-standard deviation of the within-subject percentage change in BPs from pre- to post-embolization were measured. p values, statistically significant at <=0.05, were assigned from a paired sampled t and Wilcoxon matched-pairs signed rank tests to assess whether the percentage change in BP was relevant. Results: Mean changes (pre- and post-embolization) in systolic, diastolic, and mean left UA BP measurements were: 17.74+/-17.87, 9.15+/-12.39, and 13.24+/-12.98, respectively. In the right UA, 29.76+/-24.05, 13.44+/-11.33, and 20.88+/-15.66. All assigned p values were <0.0001. Conclusion: In this study, parametric differences in uterine artery blood pressures before and after UAE were shown to correlate to an accepted angiographic endpoint. UA BP measurements can be used as an equivalent parametric non-imaging endpoint to UAE. A non-angiographic endpoint may lead to the reduction of radiation dosage to the patient and the interventional radiologist when performing UAE. (Table Presented)

Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Some studies have evaluated preoperative and intraoperative examination for inguinal hernias and their repair, noting a decrease in the rate of post-prostatectomy hernias. However, this did not eradicate post-prostatectomy hernias, indicating that this method probably missed subclinical hernias. Other studies looked at prophylactic procedures to prevent the formation of inguinal hernias at the time of prostatectomy and showed a decrease in the rate of postoperative hernias. To our knowledge this is the only series evaluating a multi-modal approach with magnetic resonance imaging, ultrasonography and examination to identify all clinical and subclinical hernias and repair them at the time of prostatectomy. This approach only subjects those patients at risk for symptomatic hernias to an additional procedure and decreases the post-prostatectomy hernia rate to <1%. OBJECTIVE: * To assess if a comprehensive evaluation to diagnose clinical and subclinical hernias and repair of these hernias at the time of open radical retropubic prostatectomy (ORRP) decreases the incidence of clinical inguinal hernias (IHs) after ORRP. PATIENTS AND METHODS: * Between 1 July 2007 and 31 July 2010, 281 consecutive men underwent ORRP by a single surgeon. * Of these men, 207 (74%) underwent comprehensive preoperative screening for IH, which included physical examination, upstanding ultrasonography and magnetic resonance imaging. * Between 12 and 24 months after ORRP, 178 (86%) of these men completed a questionnaire designed to capture development of clinical IHs. RESULTS: * Of the 178 evaluable patients, 92 (52%) were diagnosed preoperatively with IH by at least one diagnostic modality. * Forty-one and 51 of the men had bilateral or unilateral IHs, respectively for a total of 133 IHs. * No preoperative factor was significantly associated with the presence of an IH before prostatectomy. * No groin subjected to IH repair (IHR) at the time of ORRP developed a clinical IH compared with four of the 21 patients with postoperative IHs who did not undergo repair of their preoperatively diagnosed IH at the time of ORRP (P= 0.024). * Only one (0.4%) clinical IH developed in a groin that had no evidence of IH by physical examination, upstanding ultrasonography and magnetic resonance imaging before prostatectomy. CONCLUSIONS: * Our comprehensive evaluation increases the detection of IHs before ORRP. * Repair of these IHs at the time of ORRP significantly decreases the risk of developing post-prostatectomy clinical IHs.

PURPOSE: This study tested the hypothesis that topical Toll-like receptor (TLR) 7 agonist imiquimod promotes antitumor immunity and synergizes with other treatments in a model of skin-involving breast cancer. EXPERIMENTAL DESIGN: TSA mouse breast carcinoma cells were injected s.c. into syngeneic mice. Imiquimod 5% or placebo cream was applied topically on the shaved skin overlying tumors three times/wk. In some experiments, local ionizing radiation therapy (RT) was delivered to the tumor in three fractions of 8 Gy, given on consecutive days. Cyclophosphamide was given intraperitoneally (i.p.) in one dose of 2 mg/mouse. Mice were followed for tumor growth and survival. RESULTS: Treatment with imiquimod significantly inhibited tumor growth, an effect that was associated with increased tumor infiltration by CD11c(+), CD4(+), and CD8(+) cells, and abolished by depletion of CD8(+) cells. Administration of imiquimod in combination with RT enhanced significantly tumor response compared with either treatment alone (P < 0.005), and 11% to 66% of irradiated tumors completely regressed. Importantly, the addition of topical imiquimod also resulted in growth inhibition of a secondary tumor outside of the radiation field. Low-dose cyclophosphamide given before start of treatment with imiquimod and RT further improved tumor inhibition and reduced tumor recurrence. Mice that remained tumor-free rejected a tumorigenic inoculum of TSA cells, showing long-term immunologic memory. CONCLUSIONS: Topical imiquimod inhibits tumor growth and synergizes with RT. Addition of cyclophosphamide further increases the therapeutic effect and induces protective immunologic memory, suggesting that this combination is a promising strategy for cutaneous breast cancer metastases. Clin Cancer Res; 18(24); 6668-78. (c)2012 AACR.

N-acetylaspartate (NAA) is an index of neuronal integrity. We hypothesized that in healthy subjects its whole brain concentration (WBNAA) may be related to formal educational attainment, a common proxy for cognitive reserve. To test this hypothesis, 97 middle aged to elderly subjects (51-89 years old, 38% women) underwent brain magnetic resonance imaging and non-localizing proton spectroscopy. Their WBNAA was obtained by dividing their whole-head NAA amount by the brain volume. Intracranial volume and fractional brain volume, a metric of brain atrophy, were also determined. Each subject's educational attainment was the sum of his/her years of formal education. In the entire group higher education was associated with larger intracranial volume. The relationship between WBNAA and education was observed only in younger (51-70 years old) participants. In this group, education explained 21% of the variance in WBNAA. More WBNAA was related to more years of formal education in adults and younger elders. Prospective studies can determine whether this relationship reflects a true advantage from years of training versus innate characteristics predisposing a subject to higher achievements later in life. We propose that late-life WBNAA may be more affected by other factors acting at midlife and later.

Purpose: To compare histogram analysis of voxel-based whole-lesion (WL) enhancement to qualitative assessment and region-of-interest (ROI)-based enhancement analysis in discriminating the renal cell cancer (RCC) subtype clear cell RCC (ccRCC) from papillary RCC (pRCC). Materials and Methods: In this institutional review board-approved, HIPAA-compliant retrospective study, 73 patients underwent magnetic resonance (MR) imaging prior to surgery for RCC between January 2007 and January 2010. Three-dimensional fat-suppressed T1-weighted gradient-echo corticomedullary phase acquisitions, obtained before and after contrast agent administration, were transferred to a workstation at which automated registration followed by semiautomated segmentation of the RCC was performed. Percent enhancement was computed on a per-voxel basis: (SI(post) - SI(pre))/SI(pre) .100, where SI(pre) and SI(post) indicate signal intensity before and after contrast enhancement, respectively. The WL quantitative parameters of mean, median, and third quartile enhancement and histogram distribution parameters kurtosis and skewness were computed for each lesion. WL enhancement parameters were compared with ROI-based analysis and qualitative assessment with regards to diagnostic accuracy and interreader agreement in differentiating ccRCC from pRCC. Results: There were 19 pRCCs and 55 ccRCCs at pathologic examination. ccRCC had significantly higher WL mean, median, and third quartile enhancement compared with pRCC and hade significantly lower kurtosis and skewness (all P < .001). Third quartile enhancement had the highest accuracy (94.6%; area under the curve, 0.980) in discriminating ccRCC from pRCC, which was significantly higher than the accuracy of qualitative assessment (86.0%; P = .04) but not significantly higher than that of ROI enhancement (89.2%; P = .52). WL enhancement parameters had higher interreader agreement (kappa = 0.91-1.0) compared with ROI enhancement or qualitative assessment (kappa = 0.83 and 0.7, respectively) in discriminating ccRCC from pRCC. Conclusion: WL enhancement histogram analysis is feasible and can potentially be used to differentiate ccRCC from pRCC with high accuracy. (c) RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111281/-/DC1.