Faculty Bibliography

INTRODUCTION/UNASSIGNED:Tc-DTPA) tracer clearance is the gold standard for bilateral kidney function, involving extended clearance times and radioactivity. Imaging-derived total kidney volumes are functional proxies but do not probe tissue quality. METHODS/UNASSIGNED:tests. RESULTS/UNASSIGNED:= 0.880 and 0.700, respectively). In addition, MR metrics differentiated proteinuria status. DISCUSSION/UNASSIGNED:Advanced DW MRI metrics may provide surrogates of mGFR and proteinuria. Parameters from bipolar encoding in diastole (emphasizing tubular flow) and flow compensation in systole (emphasizing vascular flow) were often informative.

BACKGROUND AND OBJECTIVE/OBJECTIVE:Trimodality therapy (TMT) is an accepted bladder-preserving option for selected patients with muscle-invasive bladder cancer (MIBC). Pembrolizumab has demonstrated activity in MIBC and may enhance the effects of chemotherapy and radiation. We evaluated the safety and efficacy of adding pembrolizumab to TMT. METHODS:In this multicenter phase 2 trial, patients with MIBC received one dose of pembrolizumab followed by maximal transurethral resection, then definitive bladder radiation with concurrent low-dose gemcitabine and pembrolizumab every 3 wk for three doses. The primary end point was 2-yr bladder-intact disease-free survival (BIDFS). Secondary end points included safety, metastasis-free survival (MFS), and overall survival (OS). KEY FINDINGS AND LIMITATIONS/UNASSIGNED:Fifty-four patients were enrolled, including 48 in the efficacy cohort; 67% had clinical stage T2 disease. The 2-yr BIDFS was 60% (95% confidence interval [CI], 45-73). Two-yr MFS and OS were 81% (95% CI, 66-92) and 83% (95% CI, 69-91), respectively. Grade ≥3 treatment-related adverse events occurred in 25% of patients. Limitations include the single-arm design and modest sample size. CONCLUSIONS AND CLINICAL IMPLICATIONS/CONCLUSIONS:Pembrolizumab combined with gemcitabine-based chemoradiation was feasible and showed efficacy comparable to standard TMT. Ongoing phase 3 trials will further define its role in bladder preservation.

PURPOSE/OBJECTIVE:The aim of this study is to evaluate the treatment response of patients with osteoid osteoma (OO) following radiofrequency ablation (RFA) and identify factors influencing the time to complete pain relief post-treatment. MATERIALS AND METHODS/METHODS:This is a retrospective cohort study of patients who underwent RFA for OO between 2010 and 2023. Demographic, clinical data, and time between symptoms onset to diagnosis and RFA were recorded. CTs were reviewed for OO location (upper extremity, lower extremity, spine/pelvis), intra-articular versus extra-articular lesions, nidus size, degree of peripheral bone formation, and presence of vessel sign. Procedural related information included needle approach, RFA active tip length, and number of RFA cycles. Statistical analysis was made on factors and their correlation to complete pain relief. RESULTS:Out of 63 patients included in our study (mean age 19.3 ± 10.6), OO were located in the upper extremity (n = 7, 11%), lower extremity (n = 48, 76%), and pelvis/spine (n = 8, 13%). OO in the pelvis/spine achieved the quickest complete pain relief (14 days) compared to those in lower (25 days, 11 days longer) and upper extremity (54 days, 40 days longer) respectively (p = 0.04). Vessel sign had significant association with shorter time to complete pain relief (p = 0.03). Longer duration of symptoms until diagnosis or RFA, larger nidus, more bone formation, and extra-articular OO responded slower to RFA, though statistical significance was not reached. CONCLUSIONS:Anatomical location and certain imaging characteristics of OO may have association with time to complete pain relief following RFA. The findings can potentially help optimizing patient counseling with more realistic expectations and symptom management strategies prior to and following RFA.

PURPOSE/OBJECTIVE:This prospective, non-randomized phase II single-arm pilot trial aimed to explore favorable mid-treatment nodal response (FMNR) through CT imaging to guide de-escalated chemoradiation therapy (CRT) in patients with favorable risk, node-positive HPV-associated oropharyngeal cancer (OPC). MATERIALS AND METHODS/METHODS:. At week 4, CT imaging evaluated nodal response: ≥40% reduction warranted de-escalation to 60 Gy, while <40% reduction continued standard CRT. Primary endpoint was 2-year PFS from initiation of dose de-escalated CRT. Tissue tumor modified viral (TTMV) HPV DNA samples and DW-MRI were collected at baseline and week 4. MDADI questionnaires were collected at baseline, 1, 3, 6, 12, and 24 months. RESULTS:Of 39 patients, 26 had FMNR and underwent de-escalated treatment. 13 pts had slow mid-treatment nodal shrinkage and received standard dose. At a median follow-up of 47.4 months, the 2-year PFS was 92.1% (95% CI: 0.72-0.98) for the deescalated dose group and 92.3% for the standard dose patients (95% CI: 0.57-0.99), p=0.96. With a median survival follow up of 48.9 months (range: 16.7-77.8 months), there were no deaths or distant failures. FMNR was associated with rapid TTMV HPV DNA clearance, reduced TTMV HPV DNA flare, lower baseline and week 4 MRI diffusivity, and higher baseline and week 4 MRI diffusional kurtosis. No differences in acute or late maximum grade 3-4 toxicity by patient were noted. MDADI composite scores showed minimal clinical important difference (MCID) in the de-escalated group at 1-month post-treatment while the standard group had MCID up to 1-year post-treatment. No patients required feeding tube placement. CONCLUSIONS:De-escalated CRT using CT-based mid-treatment nodal response in favorable risk, node-positive HPV-associated OPC achieved excellent 2-year PFS and OS rates and represents a potential approach in better selecting patients for treatment de-escalation.

The development of noninvasive MRI biomarkers as surrogates of histopathological features in kidney tissue requires detailed explorations of contrast. Therefore, we studied kidney diffusion kurtosis imaging (DKI) with a wide array of encodings, including flow compensation, variable directional sampling, and cardiac gating regimes. Twelve healthy volunteers underwent DKI at 5-10 diffusion weightings (b-values) ranging from 0 to 1200 smm^-2 with 12 or 30 directional samplings, bipolar or flow-compensated diffusion gradient waveforms, and at systolic or diastolic cardiac phases. DKI biomarkers, mean diffusivity (MD) and kurtosis (MK), were interrogated using a directionally robust fitting algorithm compared to conventional fits. The combination of flow compensation and cardiac triggering at the diastolic phase in the kidneys reduced flow effects on DKI. In systole, flow-compensated waveforms significantly reduced MD and MK for both cortex and medulla: cortex MD: 3.00 versus 2.55 μm² ms^-1, medulla MD: 2.80 versus 2.39 μm² ms^-1, cortex MK: 0.58 versus 0.45, and medulla MK: 0.60 versus 0.47 (all p < 0.05). Flow suppression alleviated requirements for processing the DKI at higher minimum b-values, as neither MD nor MK significantly differed at the diastolic phase for minimum b-values of 0 versus 200 smm^-2: cortex MD: 2.30 versus 2.28 μm² ms^-1, p = 0.278; medulla MD: 2.29 versus 2.28 μm² ms^-1, p = 0.437; cortex MK: 0.37 versus 0.36, p = 0.308; and medulla MK: 0.40 versus 0.40, p = 0.904. Flow-compensated waveforms mitigate cardiac and respiratory motion-related artifacts at higher diffusion encodings in addition to microcirculation effects. The robust fitting initially developed for brain DKI is highly applicable to the kidneys because it disentangles tissue-specific directional diffusion information from artifacts.

Purpose To evaluate intravoxel incoherent motion (IVIM) biomarkers across different MRI vendors and software programs for breast cancer characterization in a two-site study. Materials and Methods This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study included 106 patients (with 18 benign and 88 malignant lesions) who underwent bilateral diffusion-weighted imaging (DWI) between February 2009 and March 2013. DWI was performed using 1.5-T (n = 6) or 3-T MRI scanners from two vendors using single-shot spin-echo echo-planar imaging or twice-refocused, bipolar gradient single-shot turbo spin-echo readout with multiple b values between 0 and 1000 sec/mm². IVIM parameters tissue diffusivity (D_t