How Can We Identify Extraprostatic Extension (EPE) Before Surgery? The Use of a Preoperative Prostate MRI EPE Scoring System to Assess Postprostatectomy Locally Advanced Prostate Cancer

Background: Distinguishing between organ-confined disease and extraprostatic extension (EPE) is crucial for the treatment of patients with prostate cancer. EPE is associated with an increased risk of biochemical recurrence, positive surgical margins, and metastatic disease. An MRI-based EPE scoring system was developed by Mehralivand in 2019; however, it has not been adopted in the Urology community. The purpose of this study is to evaluate the association of MRI-based EPE scoring with the pathologic EPE (pEPE) after radical prostatectomy. Methods: We conducted a retrospective review on a prospectively collected database of male patients who underwent a prostate MRI with EPE scoring by a trained genitourinary radiologist and subsequent robotic radical prostatectomy at our institution from September 2020 to December 2022. The associations between MRI EPE (mEPE) score and the presence of EPE on surgical pathology (pEPE) were examined using multivariable logistic regression. Results: A total of 194 patients met inclusion criteria with a median age of 63 years and prostate specific antigen (PSA) 7 ng/mL. Among those with mEPE score 3, 96% had pEPE. Those patients with an mEPE score ≥2 had an increased risk of pEPE compared with those with mEPE score 0 (odds ratio 3.79; 95% confidence interval 1.28-11.3) Furthermore, those with an mEPE score 3 were significantly more likely to have pEPE compared with those with mEPE score 0, 1 and 2 independently. Conclusion: MRI EPE is a straightforward tool that strongly correlates with the presence of pEPE. If validated prospectively, this scoring system could assist in counseling patients regarding nerve-sparing approach.

A case report of a prostate cancer metastasis in the pancreas exhibiting vascular encasement

We report a patient who presented with a 4-month history of intermittent epigastric pain. Computed tomography (CT) angiography of the abdomen demonstrated a stenotic celiac trunk but also encasement of the common proper hepatic artery, gastroduodenal artery, and proper hepatic artery by an ill-defined hypoattenuating mass of the pancreatic head. Biopsy confirmed metastatic prostate cancer to the pancreas that occurred 4 years after radiation and androgen deprivation therapy. A follow-up staging study demonstrated an osseous metastasis at the T4 spinous process. This case demonstrates an unusual case of prostate metastasis to the pancreas with the involvement of a main abdominal vessel. With treatment improvements leading to longer survival rates from prostate cancer, radiologists should be aware of atypical metastases that may arise in the long term.

Characterizing Metabolic Heterogeneity of Hepatocellular Carcinoma with Hyperpolarized 13C Pyruvate MRI and Mass Spectrometry

Purpose To characterize the metabolomic profiles of two hepatocellular carcinoma (HCC) rat models, track evolution of these profiles to a stimulated tumor state, and assess their effect on lactate flux with hyperpolarized (HP) carbon 13 (13C) MRI. Materials and Methods Forty-three female adult Fischer rats were implanted with N1S1 or McA-RH7777 HCC tumors. In vivo lactate-to-pyruvate ratio (LPR) was measured with HP 13C MRI at 9.4 T. Ex vivo mass spectrometry was used to measure intratumoral metabolites, and Ki67 labeling was used to quantify proliferation. Tumors were first compared with three normal liver controls. The tumors were then compared with stimulated variants via off-target hepatic thermal ablation treatment. All comparisons were made using the Mann-Whitney test. Results HP 13C pyruvate MRI showed greater LPR in N1S1 tumors compared with normal liver (mean [SD], 0.564 ± 0.194 vs 0.311 ± 0.057; P < .001 [n = 9]), but not for McA-RH7777 (P = .44 [n = 8]). Mass spectrometry confirmed that the glycolysis pathway was increased in N1S1 tumors and decreased in McA-RH7777 tumors. The pentose phosphate pathway was also decreased only in McA-RH7777 tumors. Increased proliferation in stimulated N1S1 tumors corresponded to a net increase in LPR (six stimulated vs six nonstimulated, 0.269 ± 0.148 vs 0.027 ± 0.08; P = .009), but not in McA-RH7777 (eight stimulated vs six nonstimulated, P = .13), despite increased proliferation and metastases. Mass spectrometry demonstrated relatively increased lactate production with stimulation in N1S1 tumors only. Conclusion Two HCC subtypes showed divergent glycolytic dependency at baseline and during transformation to a high proliferation state. This metabolic heterogeneity in HCC should be considered with use of HP 13C MRI for diagnosis and tracking. Keywords: Molecular Imaging-Probe Development, Liver, Abdomen/GI, Oncology, Hepatocellular Carcinoma © RSNA, 2024 See also commentary by Ohliger in this issue.

Evaluation of Primary Lymphedema with Intranodal Lymphangiography

PURPOSE

There are limited existing data on the lymphatic anatomy of patients with primary lymphedema (LED), which is caused by aberrant development of lymphatic channels. In addition, there is a paucity of contemporary studies that use groin intranodal lymphangiography (IL) to evaluate LED anatomy. The purpose of this retrospective observational study was to better delineate the disease process and anatomy of primary LED using groin IL.

MATERIALS AND METHODS

We identified common groin IL findings in a cohort of 17 primary LED patients performed between 1/1/2017 and 1/31/2022 at a single institution. These patients were clinically determined to have primary lymphedema and demonstrated associated findings on lower extremity MR and lymphoscintigraphy.

RESULTS

Ten patients (59%) demonstrated irregular lymph node morphology or a paucity of lymph nodes on the more symptomatic laterality. Eight patients (47%) demonstrated lymphovenous shunting from pre-existing anastomoses between the lymphatic and venous systems. Eight patients (47%) demonstrated passage of contrast past midline to the contralateral lymphatics. Finally, 12 patients (71%) failed to opacify the cisterna chyli and thoracic duct on their initial lymphangiograms. Delayed computed tomography of 3 patients showed eventual central lymphatic opacification up to the renal veins, but none of these patients showed central lymphatic opacification to the thorax.

CONCLUSION

This descriptive, exploratory study demonstrates common central groin IL findings in primary LED to highlight patterns interventional radiologists should identify and report when addressing primary LED.

Percutaneous CT-Guided Cryoablation for Locally Recurrent Prostate Cancer: Technical Feasibility, Safety, and Effectiveness

PURPOSE

To assess the feasibility and safety of using computed tomography (CT) guidance for ablation of prostate cancer in the salvage setting.

MATERIALS AND METHODS

This institutional review board-approved retrospective study of consecutive patients who presented with prostate cancer recurrence and underwent percutaneous CT-guided cryoablation was conducted between July 2020 and September 2022. A total of 18 patients met the inclusion criteria, and a total of 19 procedures were performed. Demographic details; preablation and postablation urinary, rectal, and erectile function assessment; procedure details; and preoperative and postoperative imaging findings and prostate-specific antigen (PSA) values were recorded.

RESULTS

The mean treated tumor size was 15.7 mm ± 6.2. Technical success was achieved in 18 of the 19 procedures (94.7%), with 1 procedure aborted due to inability to obtain a safe plane. The mean follow-up time was 10.0 months (range, 2.3-26.7 months) at the time of manuscript preparation. The mean PSA before ablation was 8.1 ng/mL ± 9.3, and postablation PSA nadir was 2.6 ng/mL ± 4.0 (P = .002). Of the 18 patients who had postoperative imaging, 16 (88.9%) had a complete response (ie, no evidence of residual disease), and 2 (11.1%) patients had residual disease. Overall, 16 (88.9%) of the 18 treated patients demonstrated a PSA and/or imaging response to ablation. Mild adverse events occurred in 4 (22%) of the 18 cases.

CONCLUSIONS

CT-guided cryoablation appears to be a technically feasible, safe option for treating locally recurrent prostate cancer.

Edematous Dermal Thickening on Magnetic Resonance Imaging as a Biomarker for Lymphatic Surgical Outcomes

Background and Objectives: One of the surgical treatments for breast cancer-related lymphedema (BCRL) is debulking lipectomy. The aim of this study is to investigate whether dermal thickness could be utilized as an objective indicator of post-operative changes following debulking. Materials and Methods: A retrospective review of BCRL patients who underwent debulking lipectomy was conducted. MRI-based dermal thickness was measured by two separate trained readers at 16 regions of the upper extremity. Pre- and post-operative reduction in dermal thickness was compared across the affected and unaffected (control) arms for each patient. The Wilcoxon rank sum test was used to assess for significant change. Univariate linear regression was used to assess the relationship between dermal thickness reduction and changes to LYMPH-Q scores, L-Dex scores, and relative volume change. Results: Seventeen patients were included in our analysis. There was significant reduction in dermal thickness at 5/16 regions in the affected arm. Dermal thickness change was significantly correlated with LYMPH-Q scores, L-Dex scores, and relative volume change in 2/16 limb compartments. There was predominant dermal thickening in the dorsal compartment of the upper arm and in the ventral and ulnar compartments of the forearm. Conclusions: Dermal thickness shows promising utility in tracking post-operative debulking procedures for breast cancer-related lymphedema. Further studies with larger patient populations and a variety of imaging modalities are required to continue to develop a clinically objective and reproducible method of post-surgical lymphedema staging and monitoring.

MRI of Lymphedema

Lymphedema is a devastating disease that has no cure. Management of lymphedema has evolved rapidly over the past two decades with the advent of surgeries that can ameliorate symptoms. MRI has played an increasingly important role in the diagnosis and evaluation of lymphedema, as it provides high spatial resolution of the distribution and severity of soft tissue edema, characterizes diseased lymphatic channels, and assesses secondary effects such as fat hypertrophy. Many different MR techniques have been developed for the evaluation of lymphedema, and the modality can be tailored to suit the needs of a lymphatic clinic. In this review article we provide an overview of lymphedema, current management options, and the current role of MRI in lymphedema diagnosis and management. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 5.

Rate of Incidental Edema in the Contralateral Arm of Patients with Unilateral Postsurgical Secondary Upper Extremity Lymphedema

Background: Secondary upper extremity lymphedema occurs after an insult such as surgery. One theory suggests underlying lymphatic dysfunction predisposing certain patients into developing secondary lymphedema. We aim to determine the rate of incidental edema in the contralateral upper extremity of patients with secondary unilateral lymphedema. Methods and Results: MRI of the upper extremities were obtained in patients with lymphedema who were referred by a lymphedema clinic from 2017 to 2019. Axial short-tau inversion recovery MR images of the symptomatic and contralateral arms were retrospectively reviewed and edema severity was graded. Interobserver agreement was calculated. Indocyanine green (ICG) lymphography was compared against MRI stage in symptomatic and contralateral. Age, symptom duration, body mass index (BMI), and history of chemotherapy were compared between patients with and without contralateral limb lymphedema. ICG severity was compared against MRI stage. Seventy-eight patients were analyzed. The MRI stages of symptomatic versus contralateral arms were 1.7 ± 1.1 versus 0.1 ± 0.4 (p < 0.00001). Interobserver agreement was 0.86 (0.79-0.94). Of the patients with MRI Stage 1 or above in the symptomatic arm (n = 64), 55 (82.1%) patients demonstrated no abnormality in the contralateral arm. Nine patients (14.1%) demonstrated asymptomatic edema (MRI Stage 1). The mean ICG lymphography stage of symptomatic versus contralateral arms was 1.83 ± 0.96 versus 0.04 ± 0.25 (p < 0.00001). There was no difference in the age, symptom duration, BMI, or history of chemotherapy between patients with or without edema in the contralateral arm. Conclusion: Asymptomatic contralateral edema was detected in 14.1% of patients with unilateral secondary upper extremity lymphedema using MRI modality.

A Large-Scale Proteomics Resource of Circulating Extracellular Vesicles for Biomarker Discovery in Pancreatic Cancer

Pancreatic cancer has the worst prognosis of all common tumors. Earlier cancer diagnosis could increase survival rates and better assessment of metastatic disease could improve patient care. As such, there is an urgent need to develop biomarkers to diagnose this deadly malignancy earlier. Analyzing circulating extracellular vesicles (cEVs) using 'liquid biopsies' offers an attractive approach to diagnose and monitor disease status. However, it is important to differentiate EV-associated proteins enriched in patients with pancreatic ductal adenocarcinoma (PDAC) from those with benign pancreatic diseases such as chronic pancreatitis and intraductal papillary mucinous neoplasm (IPMN). To meet this need, we combined the novel EVtrap method for highly efficient isolation of EVs from plasma and conducted proteomics analysis of samples from 124 individuals, including patients with PDAC, benign pancreatic diseases and controls. On average, 912 EV proteins were identified per 100μL of plasma. EVs containing high levels of PDCD6IP, SERPINA12 and RUVBL2 were associated with PDAC compared to the benign diseases in both discovery and validation cohorts. EVs with PSMB4, RUVBL2 and ANKAR were associated with metastasis, and those with CRP, RALB and CD55 correlated with poor clinical prognosis. Finally, we validated a 7-EV protein PDAC signature against a background of benign pancreatic diseases that yielded an 89% prediction accuracy for the diagnosis of PDAC. To our knowledge, our study represents the largest proteomics profiling of circulating EVs ever conducted in pancreatic cancer and provides a valuable open-source atlas to the scientific community with a comprehensive catalogue of novel cEVs that may assist in the development of biomarkers and improve the outcomes of patients with PDAC.

Omental vascularized lymph node transplant for the treatment of breast lymphedema: A case report

Breast lymphedema is a type of breast cancer related lymphedema that leads to significant discomfort and negative impact on body image. Conservative therapy and lymphovenous bypass have been previously described as possible treatment methods for breast lymphedema, however, a unified approach to treatment is lacking. The current report describes a case of breast lymphedema successfully treated with vascularized lymph node transfer (VLNT) after failed attempt at management with conservative therapy. The patient is a 48-year-old female with right-sided breast cancer who underwent breast conservation therapy in 2015 and subsequently developed pain and swelling of the right breast. The diagnosis of breast lymphedema was supported by clinical evaluation as well as MRI, lymphoscintigraphy, and lymphography. In consultation with a breast surgeon, breast lymphedema was determined not to be an indication for mastectomy. The patient was offered and underwent an omental VLNT to the right breast. A 20 cm segment of omentum with associated gastroepiploic vessels and lymph nodes was harvested, transferred to the right axilla and gastroepiploic vessels were anastomosed to the recipient thoracodorsal vessels. The patient tolerated the procedure well and there were no complications. Additional donor sites were considered, such as the groin and submental regions, but an omental flap was favored in this case because of the lower risk of donor site lymphedema. In the years following, the patient reported significant improvement in symptoms as well as objective reduction of edema on MRI. We propose the consideration of VLNT for breast lymphedema refractory to other methods of management.

Comparative Effectiveness of Magnetic Resonance Imaging-Ultrasound Fusion Versus In-bore Magnetic Resonance Imaging-targeted Prostate Biopsy

OBJECTIVE

To examine the comparative effectiveness of magnetic resonance imaging-ultrasound (MRI-U/S) fusion biopsy and in-bore MRI-targeted biopsy.

METHODS

We identified men aged 18-89 with a diagnosis of elevated prostate specific antigen (PSA) or Gleason 6 prostate cancer on active surveillance who underwent MRI-U/S fusion prostate biopsy (12-core + targeted) in the office or in-bore MRI-targeted biopsy (MRI-IB; targeted only). The cancer detection rate (CDR; Gleason 6-10) and clinically significant CDR (csCDR; Gleason 7-10) were compared across biopsy techniques, adjusted for patient and radiographic features.

RESULTS

A total of 280 patients (346 lesions) were included, of whom 23.9% were on active surveillance for Gleason 6 prostate cancer. In the per-patient analyses, there was no statistically significant difference in adjusted overall CDR (64.1% vs 54.2%; P = .24) or csCDR (36.5% vs 37.9%; P = .85) between MRI-U/S and MRI-IB biopsy. In the per-lesion analyses, there was no statistically significant difference in adjusted overall CDR (45.7% vs 50.1%; P = .49) between MRI-U/S and MRI-IB biopsy, but MRI-IB biopsy was associated with a higher csCDR than MRI-U/S biopsy (32.8% vs 21.4%; P = .02).

CONCLUSION

We observed no statistically significant differences in cancer detection rates between MRI-U/S fusion biopsy and MRI-IB biopsy in per-patient analyses. However, MRI-IB biopsy was associated with higher csCDR when considering targeted biopsy cores only. These results suggest that systematic cores should be obtained when performing MRI-U/S fusion biopsy.

PFKFB3-mediated Pro-glycolytic Shift in Hepatocellular Carcinoma Proliferation

BACKGROUND & AIMS

Metabolic reprogramming, in particular, glycolytic regulation, supports abnormal survival and growth of hepatocellular carcinoma (HCC) and could serve as a therapeutic target. In this study, we sought to identify glycolytic regulators in HCC that could be inhibited to prevent tumor progression and could also be monitored in vivo, with the goal of providing a theragnostic alternative to existing therapies.

METHODS

An orthotopic HCC rat model was used. Tumors were stimulated into a high-proliferation state by use of off-target liver ablation and were compared with lower-proliferating controls. We measured in vivo metabolic alteration in tumors before and after stimulation, and between stimulated tumors and control tumors using hyperpolarized 13C magnetic resonance imaging (MRI) (h13C MRI). We compared metabolic alterations detected by h13C MRI to metabolite levels from ex vivo mass spectrometry, mRNA levels of key glycolytic regulators, and histopathology.

RESULTS

Glycolytic lactate flux increased within HCC tumors 3 days after tumor stimulation, correlating positively with tumor proliferation as measured with Ki67. This was associated with a shift towards aerobic glycolysis and downregulation of the pentose phosphate pathway detected by mass spectrometry. MRI-measured lactate flux was most closely coupled with PFKFB3 expression and was suppressed with direct inhibition using PFK15.

CONCLUSIONS

Inhibition of PFKFB3 prevents glycolytic-mediated HCC proliferation, trackable by in vivo h13C MRI.

Real-time diagnosis and Gleason grading of prostate core needle biopsies using nonlinear microscopy

Rapid histologic assessment of fresh prostate biopsies may reduce patient anxiety, aid in biopsy sampling, and enable specimen triaging for molecular/genomic analyses and research that could benefit from fresh tissue analysis. Nonlinear microscopy (NLM) is a fluorescence microscopy technique that can produce high-resolution images of freshly excised tissue resembling formalin-fixed paraffin-embedded (FFPE) H&E. NLM enables evaluation of tissue up to ~100 µm below the surface, analogous to serial sectioning, but without requiring microtome sectioning. One hundred and seventy biopsies were collected from 63 patients who underwent in-bore MRI or MRI/ultrasound fusion biopsy procedures. Biopsies were stained in acridine orange and sulforhodamine 101, a nuclear and cytoplasmic/stromal fluorescent dye, for 45 s. Genitourinary pathologists evaluated the biopsies using NLM by translating the biopsies in real time to areas of interest and NLM images were recorded. After NLM evaluation, the biopsies were processed for standard FFPE H&E and similarities and differences between NLM and FFPE H&E were investigated. Accuracies of NLM diagnoses and Gleason scores were calculated using FFPE histology as the gold standard. Pathologists achieved a 92.4% sensitivity (85.0-96.9%, 95% confidence intervals) and 100.0% specificity (94.3-100.0%) for detecting carcinoma compared to FFPE histology. The agreement between the Grade Group determined by NLM versus FFPE histology had an unweighted Cohen's Kappa of 0.588. The average NLM evaluation time was 2.10 min per biopsy (3.08 min for the first 20 patients, decreasing to 1.54 min in subsequent patients). Further studies with larger patient populations, larger number of pathologists, and multiple institutions are warranted. NLM is a promising method for future rapid evaluation of prostate needle core biopsies.

Spectrum of MRI Features of Mucin-producing Neoplasms in the Abdomen and Pelvis

Mucin-producing neoplasms in the abdomen and pelvis are a distinct entity, separate from simple fluid-containing neoplasms and loculated fluid collections. Mucin is a thick gelatinous substance and-owing to its high water content-has imaging features that can be mistaken for those of simple fluid-containing neoplasms with multiple imaging modalities. However, mucin-producing neoplasms arise from specific organs in the abdomen and pelvis, with unique imaging appearances, knowledge of which is important to guide accurate diagnosis and management. With its large field of view and high soft-tissue resolution, MRI has advantages over other imaging modalities in characterizing these neoplasms. The authors focus on the spectrum of MRI features of such mucin-producing neoplasms and illustrate how-despite a varied organ origin-some of these neoplasms share similar MRI and histopathologic features, thereby helping narrow the differential diagnosis. One common finding in these tumors is that the presence of internal complexity and solid enhancing components increases as the degree of malignant transformation increases. Lack of internal complexity generally indicates benignity. These tumors have a varied range of prognosis; for example, a low-grade appendiceal mucinous neoplasm is indicative of a good prognosis, while a mucinous tumor of the rectum is known to manifest at an early age with aggressive behavior and poorer prognosis compared with its nonmucinous counterpart. Online supplemental material is available for this article. ^©RSNA, 2022.

Use of MRI and Ga-68 DOTATATE for the detection of neuroendocrine liver metastases

PURPOSE

To compare detection rates of NET liver metastases of MRI and Ga-68-DOTATATE PET/CT to provide more clarity when selecting diagnostic imaging tests for NET staging.

METHODS

In this IRB-approved single-institution retrospective study, all patients with pathology-proven NET who underwent Ga-68-DOTATATE and MRI scans within 8 weeks of each other (3/2017-2/2020) were reviewed. Number of metastases for each patient on diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI, and Ga-68 DOTATATE were recorded by two blinded radiologists, followed by consensus review with two separate blinded readers for MRI and nuclear medicine. Per-lesion and -modality scoring at each lesion location were then performed in consensus. Per-patient linear regression was performed comparing MRI and Ga-68 DOTATATE detection rates for each reader and in consensus, and per-lesion-matched pair difference means were used to compare detection frequency between modalities.

RESULTS

32 patients (mean age 59 years, 59.4% male) and 90 liver metastases were analyzed. Intraclass coefficients (ICC) [95% CI] between the two readers were 0.97 [0.95, 0.99], 0.89 [0.82, 0.94], and 0.98 [0.97, 0.99] for Ga-68 DOTATATE, DWI, and DCE, respectively. Matched per-lesion mean differences were + 0.17 ± 0.07 (p = 0.01) and + 0.22 ± 0.06 (p =  < 0.001) for DWI versus Ga-68 DOTATATE and DCE vs Ga-68 DOTATATE, respectively, favoring MRI. Case-based linear regressions estimate that DWI and DCE detect 1.28 [1.07, 1.49] and 1.33 [1.12, 1.54] lesions, respectively, for each one detected on Ga-68 DOTATATE.

CONCLUSION

MRI detects more hepatic NET metastasis in comparison to Ga-68 DOTATATE. Liver MRI should be performed in concert with Ga-68 DOTATATE in NET staging.

The Boston lymphatic center's early experience with lymph node transplantation to the upper extremity

Aim

Although vascularized lymph node transplantation (VLNT) has gained recognition as an effective treatment option for lymphedema, no consensus on the timing of transplant with other lymphatic procedures has been established. The aim of this study is to describe our institutional experience with VLNT, including our staged approach and report postoperative outcomes.

Methods

A retrospective review of patients who underwent VLNT for upper extremity lymphedema from May 2017 to April 2022 was conducted. Patients were divided into fat- or fluid-dominant phenotypes based on preoperative workup. Patients with a minimum of 12-month follow-up were included. Records were reviewed for demographic, intraoperative, and surveillance data.

Results

Twenty-three patients underwent VLNT of the upper extremity during the study period, of which eighteen met the study criteria. Nine patients had fluid-dominant disease and nine patients had fat-dominant disease and had undergone prior debulking at our institution. Fluid-dominant patients demonstrated slight reductions in limb volume and hours in compression, and improvement in quality-of-life scores at twelve months. Fat-dominant patients who underwent prior debulking had a slight increase in limb volume without a change in hours of compression, and demonstrated improvements in quality-of-life scores in nearly all subdomains. Overall, 17% of patients discontinued compression therapy entirely. Improvement in extremity edema was present in 83% of postoperative MRIs.

Conclusion

VLNT had varying effects on limb measurements while reliably improving quality-of-life and allowing for the potential of discontinuing compression. Utilizing a staged approach wherein debulking is performed upfront may be particularly beneficial for patients with fat-dominant disease.

Organoid Sensitivity Correlates with Therapeutic Response in Patients with Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) remains a significant health issue. For most patients there are no options for targeted therapy and existing treatments are limited by toxicity. The HOPE trial (Harnessing Organoids for PErsonalized Therapy) was a pilot feasibility trial aiming to prospectively generate patient derived organoids (PDOs) from patients with PDAC and test their drug sensitivity and correlation with clinical outcomes.

EXPERIMENTAL DESIGN

PDOs were established from a heterogeneous population of patients with PDAC including both basal and classical PDAC subtypes.

RESULTS

A method for classifying PDOs as sensitive or resistant to chemotherapy regimens was developed to predict the clinical outcome of study subjects. Drug sensitivity testing on PDOs correlated with clinical responses to treatment in individual patients.

CONCLUSION

These data support the investigation of PDOs to guide treatment in prospective interventional trials in PDAC.

Use of non-contrast MR in diagnosing secondary lymphedema of the upper extremities

PURPOSE

The purpose of the study is to determine if a combination of dermal thickening and subcutaneous fluid honeycombing on non-contrast MRI, termed the dermal rim sign (DRS), can be diagnostically analogous to dermal backflow seen on lymphoscintigraphy in patients with secondary upper extremity lymphedema.

MATERIALS AND METHODS

Upper extremity MRI and lymphoscintigraphy were performed on patients referred to a multidisciplinary lymphedema clinic for suspicion of secondary lymphedema. Sensitivity, specificity, and positive and negative predictive values of DRS on MRI in detecting dermal backflow on lymphoscintigraphy and the correlation between DRS, Indocyanine Green (ICG) lymphography, bioimpedence L-Dex® ratio and MRI Lymphedema Staging were calculated. Weighted interobserver agreements on the presence and location of DRS on MRI were calculated.

RESULTS

Of the 45 patients in the study, 91.1% (41/45) of patients had history of breast cancer. The average age was 58.4 ± 10.5 years, with a mean symptom duration of 4.7 ± 4.4 years. The mean BMI was 30.5 ± 7.0 kg/m². Interobserver agreement on the presence and the extent of DRS on MRI was 0.93 [95% confidence-interval: 0.80-1]. DRS was present in 97% (32/33) of patients who demonstrated dermal backflow on lymphoscintigraphy. Sensitivity, specificity, PPV, and NPV of DRS were 96.6% [81.7%-99.9%], and 75.0% [47.6%-92.7%], 87.5% [74.9%-94.3%], and 92.3% [63.1%-98.8%]. DRS was associated with severity on ICG lymphography and bioimpedance (both p < 0.001).

CONCLUSIONS

DRS on non-contrast MRI is highly predictive of dermal backflow and correlates with clinical measures of lymphedema severity. DRS may be used as an independent diagnostic biomarker to identify patients who would benefit from dedicated exams.

Role of the radiologist at HCC multidisciplinary conference and use of the LR-TR algorithm for improving workflow

Multidisciplinary conferences (MDCs) play a major role in management and care of oncology patients. Hepatocellular carcinoma (HCC) is a complex disease benefiting from multidisciplinary discussions to determine optimal patient management. A multitude of liver-directed locoregional therapies have emerged allowing for more options for treatment of HCC. A radiologist dedicated to HCC-MDC is an important member of the team contributing to patient care in multiple ways. The radiologist plays a key role in image interpretation guiding initial therapy discussions as well as interpreting post-treatment imaging following liver-directed therapy. Standardization of image interpretation can lead to more consistent treatment received by the patient as well as accurate assessment of transplant eligibility. The radiologist can facilitate this process using structured reporting that is also supported by stakeholders involved in interdisciplinary management of liver diseases. The Liver Imaging Reporting and Data System (LI-RADS), is a living document which offers a standardized reporting algorithm for consistent communication of radiologic findings for HCC screening and characterization of liver observations in patients at risk for HCC. The LI-RADS post-treatment algorithm (LR-TR algorithm) has been developed to standardize liver observations following liver-directed locoregional therapy. This review article focuses on the role of the radiologist at HCC-MDC and implementation of the LR-TR algorithm for improving workflow.

Abstract 2807: Variations in glycolytic activity of HCC subtypes as monitored by in vivo h 13C MRI

Hepatocellular carcinoma (HCC) is the 4th leading cause of cancer-related death worldwide. Despite therapeutic advancements, a significant proportion of patients progress, highlighting the need to improve diagnostic approaches to monitor therapy. Radiofrequency ablation (RFA), an accepted locoregional therapy for early HCC, can stimulate more aggressive tumor biology within under-treated or distant tumors. Increased glycolytic activity is a hallmark feature of cancer, but variations in metabolism and its link to tumor aggression can impact the sensitivity of HCC to therapies affecting these pathways. Tumor metabolic phenotypes can be characterized by hyperpolarized 13C MRI (h13C MRI), which can also be used to assess treatment response. In this study, we used orthotopic rat HCC models with two different cell lines N1S1 and MCA-RH7777, and analyzed their mRNA expression of glycolysis-related genes and in vivo glycolytic activity with h13C MRI. We then partially-treated tumors with radiofrequency ablation (RFA) and used h13C MRI to measure in vivo tumor metabolism before and 3 days after RFA to compare them to histologic and phenotypical measures of disease progression.

N1S1 tumors grew only as single lesions, while MCA-RH7777 rapidly produced intra-hepatic and distal metastases. Glycolysis-related genes including HK2, HK3, PFKFB3, and MCT4 were highly expressed in N1S1, but not in MCA-RH7777, while GPT1 was highly expressed in MCA-RH7777 but not in N1S1. In vivo h13C MRI demonstrated significantly increased 13C lactate flux in N1S1 tumor compared to the background normal liver, while 13C lactate flux in MCA-RH7777 rat model did not, consistent with mRNA expression patterns.

Tumor 13C lactate flux was significantly increased and 13C alanine flux was significantly decreased following partial RFA treatment to N1S1 tumors when compared to untreated tumors, which was associated with an increase in tumor Ki67 expression. However, no change was seen on h13C MRI between the RFA and control arms in MCA-RH7777 tumors, even though growth and total tumor burden progressed significantly more following RFA. In contrast to N1S1, there was also no difference between 13C lactate flux and 13C alanine flux within MCA-RH7777 tumors and the neighboring normal hepatic parenchyma, suggesting that glycolytic activity in these tumors did not drive RFA-stimulated progression. Targeting of glycolytic pathways as a potential therapy for HCC may therefore be limited to certain subtypes, and h13C MRI may be used to select for sensitivity.

Citation Format: Qianhui Dou, Aaron K. Grant, Cody Callahan, Muneeb Ahmed, Leo L. Tsai. Variations in glycolytic activity of HCC subtypes as monitored by in vivo h 13C MRI [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2807.

In vivo detection of distal tumor glycolytic flux stimulated by hepatic ablation in a breast cancer model using hyperpolarized 13C MRI

PURPOSE

Hepatic thermal ablation therapy can result in c-Met-mediated off-target stimulation of distal tumor growth. The purpose of this study was to determine if a similar effect on tumor metabolism could be detected in vivo with hyperpolarized ¹³C MRI.

MATERIALS AND METHODS

In this prospective study, female Fisher rats (n = 28, 120-150 g) were implanted with R3230 rat breast adenocarcinoma cells and assigned to either: sham surgery, hepatic radiofrequency ablation (RFA), or hepatic RFA + adjuvant c-Met inhibition with PHA-665752 (RFA + PHA). PHA-665752 was administered at 0.83 mg/kg at 24 h post-RFA. Tumor growth was measured daily. MRI was performed 24 h before and 72 h after treatment on 14 rats, and the conversion of ¹³C-pyruvate into ¹³C-lactate within each tumor was quantified as lactate:pyruvate ratio (LPR). Comparisons of tumor growth and LPR were performed using paired and unpaired t-tests.

RESULTS

Hepatic RFA alone resulted in increased growth of the distant tumor compared to sham treatment (0.50 ± 0.13 mm/day versus 0.11 ± 0.07 mm/day; p < 0.001), whereas RFA + PHA (0.06 ± 0.13 mm/day) resulted in no significant change from sham treatment (p = 0.28). A significant increase in LPR was seen following hepatic RFA (+0.016 ± 0.010, p = 0.02), while LPR was unchanged for sham treatment (-0.048 ± 0.051, p = 0.10) or RFA + PHA (0.003 ± 0.041, p = 0.90).

CONCLUSION

In vivo hyperpolarized ¹³C MRI can detect hepatic RFA-induced increase in lactate flux within a distant R3230 tumor, which correlates with increased tumor growth. Adjuvant inhibition of c-Met suppresses these off-target effects, supporting a role for the HGF/c-Met signaling axis in these tumorigenic responses.

Breast Cancer-Related Lymphedema: Magnetic Resonance Imaging Evidence of Sparing Centered Along the Cephalic Vein

BACKGROUND

 A distinct pattern of edema distribution is seen in breast cancer-related lymphedema. The area of edema sparing has not been characterized in relation to anatomy. Specifically, alternate lymphatic pathways are known to travel adjacent to the cephalic vein. Our study aims to define the location of edema sparing in the arm relative to the cephalic vein.

METHODS

 A retrospective review of patients who underwent magnetic resonance imaging (MRI) between March 2017 and September 2018 was performed. Variables including patient demographics, arm volumes, and MRI data were extracted. MRIs were reviewed to define the amount of sparing, or angle of sparing, and the deviation between the center of sparing and the cephalic vein, or angle of deviation.

RESULTS

 A total of 34 consecutive patients were included in the analysis. Five patients demonstrated circumferential edema (no sparing) and 29 patients demonstrated areas of edema sparing. Advanced age (69.7 vs. 57.6 years) and greater excess arm volume (40.4 vs. 20.8%) correlated with having circumferential edema without sparing (p = 0.003). In 29 patients with areas of edema sparing, the upper arm demonstrated the greatest angle of sparing (183.2 degrees) and the narrowest in the forearm (99.9 degrees; p = 0.0032). The mean angle of deviation to the cephalic vein measured 3.2, -0.1, and -5.2 degrees at the upper arm, elbow, and forearm, respectively.

CONCLUSION

 Our study found that the area of edema sparing, when present, is centered around the cephalic vein. This may be explained by the presence of the Mascagni-Sappey (M-S) pathway as it is located alongside the cephalic vein. Our findings represent a key springboard for additional research to better elucidate any trends between the presence of the M-S pathway, areas of sparing, and severity of lymphedema.

Use of ring-enhancement and focal necrosis to differentiate pancreatic adenosquamous carcinoma from pancreatic ductal adenocarcinoma on CT and MRI

PURPOSE

To assess the ability of the ring-enhancing sign and focal necrosis to diagnose adenosquamous carcinoma (ASqC), a variant of pancreatic ductal adenocarcinoma (PDAC), on MRI and CT.

METHODS

The following features of ASqC and conventional PDAC were evaluated on CT and MRI: tumor size, location, margins, borders (non-exophytic, exophytic), and T1 signal intensity. Two readers, blinded to histopathology results, rated their confidence in detecting ring-enhancement and focal necrosis (FN) on a 5-point Likert scale on both MRI and CT. Inter-reader agreement was assessed with Cohen's kappa (k).

RESULTS

A total of 24 patients were included: eight patients with treatment naïve and histologically proven ASqC (six women, mean age: 63, range: 40-75) and 16 patients with PDAC (eight women, mean age: 67, range: 47-83). Statistically significant differences between ASqC and PDAC were seen in tumor size, location, presence of FN, and ring enhancement (p = 0.01-0.037). The readers were more confident in depicting the key differentiating feature ring-enhancement in ASqC on MRI compared to CT (confidence 1.71 ± 0.49 vs. 0.88 ± 0.35, p = 0.017) with moderate inter-reader agreement (k = 0.46 and 0.5, respectively). FN showed substantial inter-reader agreement on MR and moderate agreement on CT (k = 0.67 and 0.5, respectively).

CONCLUSIONS

Compared to CT, MRI depicts ring-enhancement in ASqC with greater reader confidence and FN in ASqC with higher inter-reader agreement. The concurrent presence of these two imaging features should raise high suspicion for ASqC.

Arterial Spin Labeled Perfusion MRI for the Evaluation of Response to Tyrosine Kinase Inhibition Therapy in Metastatic Renal Cell Carcinoma

Background Tumor perfusion may inform therapeutic response and resistance in metastatic renal cell carcinoma (RCC) treated with antiangiogenic therapy. Purpose To determine if arterial spin labeled (ASL) MRI perfusion changes are associated with tumor response and disease progression in metastatic RCC treated with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs). Materials and Methods In this prospective study (ClinicalTrials.gov identifier: NCT00749320), metastatic RCC perfusion was measured with ASL MRI before and during sunitinib or pazopanib therapy between October 2008 and March 2014. Objective response rate (ORR) and progression-free survival (PFS) were calculated. Perfusion was compared between responders and nonresponders at baseline, at week 2, after cycle 2 (12 weeks), after cycle 4 (24 weeks), and at disease progression and compared with the ORR by using the Wilcoxon rank sum test and with PFS by using the log-rank test. Results Seventeen participants received sunitinib (mean age, 59 years ± 7.0 [standard deviation]; 11 men); 11 participants received pazopanib (mean age, 63 years ± 6.6; eight men). Responders had higher baseline tumor perfusion than nonresponders (mean, 404 mL/100 g/min ± 213 vs 199 mL/100 g/min ± 136; P = .02). Perfusion decreased from baseline to week 2 (-53 mL/100 g/min ± 31; P < .001), after cycle 2 (-65 mL/100 g/min ± 25; P < .001), and after cycle 4 (-79 mL/100 g/min ± 15; P = .008). Interval reduction in perfusion at those three time points was not associated with ORR (P = .63, .29, and .27, respectively) or PFS (P = .28, .27, and .32). Perfusion increased from cycle 4 to disease progression (51% ± 11; P < .001). Conclusion Arterial spin labeled perfusion MRI may assist in identifying responders to vascular endothelial growth factor receptor tyrosine kinase inhibitors and may help detect early evidence of disease progression in patients with metastatic renal cell carcinoma. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Goh and De Vita in this issue.

Characterizing T2 iso- and hypo-intense renal masses on MRI: Can templated algorithms improve accuracy?

PURPOSE

To assess if a templated algorithm can improve the diagnostic performance of MRI for characterization of T2 isointense and hypointense renal masses.

METHODS

In this retrospective study, 60 renal masses with histopathologic diagnoses that were also confirmed as T2 iso- or hypointense on MRI were identified (mean ± standard deviation, range: 3.9 ± 2.5, 1.0-13.7 cm). Two semi-quantitative diagnostic algorithms were created based on MRI features of renal masses reported in the literature. Three body-MRI trained radiologists provided clinical diagnoses based on their experience and separately provided semiquantitative data for each components of the two algorithms. The algorithms were applied separately by a radiology trainee without additional interpretive input. Logistic regression was used to compare the accuracy of the three methods in distinguishing malignant versus benign lesions and in diagnosing the exact histopathology. Inter-reader agreement for each method was calculated using Fleiss' kappa statistics.

RESULTS

The accuracy of the two algorithms and clinical experience were similar (70%, 69%, and 64%, respectively, p = 0.22-0.32), with fair to moderate inter-reader agreement (Fleiss's kappa: r = 0.375, r = 0.308, r = 0.375, respectively, all p < 0.0001). The accuracy of the two algorithms and clinical experience in diagnosing specific histopathology were also no different from each other (34%, 29%, and 32%, respectively, p = 0.49-0.74), with fair to moderate inter-reader agreement (Fleiss's kappa: r = 0.20, r = 0.28, r = 0.375, respectively, all p < 0.0001).

CONCLUSION

Semi-quantitative templated algorithms based on MRI features of renal masses did not improve the ability to diagnose T2 iso- and hypointense renal masses when compared to unassisted interpretation by body MR trained subspecialists.

MRI characterization of focal liver lesions in non-cirrhotic patients: assessment of added value of gadoxetic acid-enhanced hepatobiliary phase imaging

Background

To evaluate the added value of the hepatobiliary (HPB) phase in gadoxetic acid-enhanced magnetic resonance imaging (MRI) in characterizing newly discovered indeterminate focal liver lesions in non-cirrhotic patients.

Results

One-hundred and twenty-five non-cirrhotic patients (median age, 46 years; range, 20–85 years; 100 females) underwent gadoxetic acid-enhanced MRI, including the 20-min delayed HPB phase, for characterization of newly discovered focal liver lesions. Images were independently evaluated by two blinded, board-certified abdominal radiologists (R1 and R2) who characterized liver lesions without and with assessment of the HPB phase images in two separate readout sessions. Confidence in diagnosis was scored on a scale from 0 to 3. Inter-observer agreement was assessed using Cohen κ statistics. Change in diagnosis and confidence in diagnosis were evaluated by Wilcoxon signed rank test. There was no significant change in diagnosis before and after evaluation of the HPB phase for both readers (p = 1.0 for R1; p = 0.34 for R2). Confidence in diagnosis decreased from average 2.8 ± 0.45 to 2.6 ± 0.59 for R1 and increased from 2.6 ± 0.83 to 2.8 ± 0.46 for R2. Change in confidence was only statistically significant for R1 (p = 0.003) but not significant for R2 (p = 0.49). Inter-reader agreement in diagnosis was good without (k = 0.66) and with (k = 0.75) inclusion of the HPB phase images.

Conclusions

The added information obtained from the HPB phase of gadoxetic acid-enhanced MRI does not change the diagnosis or increase confidence in diagnosis when evaluating new indeterminate focal liver lesions in non-cirrhotic patients.

Abstract 2785: 13C-MRI detects increased lactate flux in HCC following hepatic thermal A\ablation and correlates with PFKFB3 Expression

Thermal ablation (TA) is an accepted therapy for early HCC and hepatic metastases from colorectal and breast cancers. However, suboptimal TA is a risk factor for early HCC recurrence and has been associated with a reduction in overall survival. This effect has been attributed to hypoxic response in periablative tissue mediated by HIF-1. Malignant transformation leads to increased anaerobic glycolysis even under normoxic conditions. This process is detectable by hyperpolarized 13C MRI (h13C MRI), which enables real-time high-resolution imaging of the conversion from pyruvate to lactate and may be used as a potential predictor for therapeutic response in HCC. We have identified two potential metabolic regulators and therapeutic targets with a direct link to lactate flux which may be monitored with h13C MRI. PFKFB3 has been identified as a crucial metabolic factor in several cancer types, encoding for inducible 6-phosphofructo-2-kinase and enhancing production of F2,6P2, consequently activating PK1 and glycolysis. Expression levels of PFKFB3 have been found to be higher in malignancies than in normal tissues, attributed to loss of glycolytic control and accelerating neoplastic activity. Hexokinase 3 (HK3), a key catalyst in the first committed steps in glucose metabolism, is also a key promoter involved in epithelial-mesenchymal transition. When we exposed an HCC rat cell line, N1S1, to heat stress, simulating the marginal zone of TA therapy, 20%-90% of cells survived at 40°C-50°C and there was no survival by 55°C. 5-8 days following this treatment, cell proliferation and mRNA expression of glycolysis-related genes were analyzed. Cellular proliferation rate was significantly higher in the heat-treated groups. mRNA expression of PFKFB3 was increased after thermal treatment, while HK3 expression was significantly decreased. We then developed an in vivo orthotopic rat model of a solitary N1S1 HCC and used h13C MRI to measure in vivo tumor lactate flux in response to radiofrequency ablation (RFA), a type of thermal ablation, of adjacent normal hepatic tissue, simulating local treatment of a distant lesion. h13C MRI demonstrated significantly increased tumor 13C lactate flux in the RFA arm relative to the control group (change in lactate-to-pyruvate ratio of 0.236±0.278 vs -0.035±0.107, p=0.0465, n=6), while background liver lactate flux was unchanged. We found that this correlated with mRNA expression of PFKFB3 and HK3, which was statistically significantly greater within tumors from the RFA group compared to control tumors (PFKFB3, 1.052±0.091 vs 0.655±0.294, p=0.0004, n=6; HK3, 0.751±0.130 vs 0.501±0.163, p=0.0036, n=6). The PFKFB3 expression patterns were concordant between in vitro and in vivo experiments. Our data shows that PFKFB3 may be an attractive treatment target for HCC, and h13C MRI may be a noninvasive technique well-suited to monitor treatment response.

Citation Format: Qianhui Dou, Aaron K. Grant, Cody Callahan, David Mwin, Muneeb Ahmed, Leo L. Tsai. 13C-MRI detects increased lactate flux in HCC following hepatic thermal A\ablation and correlates with PFKFB3 Expression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2785.

MRI staging of upper extremity secondary lymphedema: correlation with clinical measurements

OBJECTIVES

Staging of upper extremity lymphedema is needed to guide surgical management, but is not standardized due to lack of accessible, quantitative, or precise measures. Here, we established an MRI-based staging system for lymphedema and validate it against existing clinical measures.

METHODS

Bilateral upper extremity MRI and lymphoscintigraphy were performed on 45 patients with unilateral secondary lymphedema, due to surgical intervention, who were referred to our multidisciplinary lymphedema clinic between March 2017 and October 2018. MRI short-tau inversion recovery (STIR) images were retrospectively reviewed. A grading system was established based on the cross-sectional circumferential extent of subcutaneous fluid infiltration at three locations, labeled MRI stage 0-3, and was compared to L-Dex®, ICG lymphography, volume, lymphedema quality of life (LYMQOL), International Society of Lymphology (ISL) stage, and lymphoscintigraphy. Linear weighted Cohen's kappa was calculated to compare MRI staging by two readers.

RESULTS

STIR images on MRI revealed a predictable pattern of fluid infiltration centered on the elbow and extending along the posterior aspect of the upper arm and the ulnar side of the forearm. Patients with higher MRI stage were more likely to be in ISL stage 2 (p = 0.002) or to demonstrate dermal backflow on lymphoscintigraphy (p = 0.0002). No correlation was found between MRI stages and LYMQOL. Higher MRI stage correlated with abnormal ICG lymphography pattern (r_s = 0.63, p < 0.0001), larger % difference in limb volume (r_s = 0.68, p < 0.0001), and higher L-Dex® ratio (r_s = 0.84, p < 0.0001). Cohen's kappa was 0.92 (95% CI, 0.85-1.00).

CONCLUSION

An MRI staging system for upper extremity lymphedema offers an improved non-invasive precision marker for lymphedema for therapeutic planning.

KEY POINTS

• Diagnosis and staging of patients with secondary upper extremity lymphedema may be performed with non-contrast MRI, which is non-invasive and more readily accessible compared to lymphoscintigraphy and evaluation by lymphedema specialists. • MRI-based staging of secondary upper extremity lymphedema is highly reproducible and could be used for long-term follow-up of patients. • In patients with borderline clinical measurements, MRI can be used to identify patients with early-stage lymphedema.

Differentiation of pancreatic head ductal adenocarcinoma from inflammatory pancreatic pseudomass by MR cholangio-pancreatography: utility of the duct-interrupted, corona, and attraction signs

PURPOSE

To determine sensitivity and specificity of the "duct-interrupted," "corona," and "attraction" signs on MR cholangio-pancreatography (MRCP) in distinguishing pancreatic head ductal adenocarcinoma (PDAC) from inflammatory pancreatic pseudomass (IPP).

MATERIALS AND METHODS

This study included 53 adults (33 men and 20 women, mean age, 55 years; range, 17-87 years) with a pancreatic head mass who underwent MRCP. Three blinded radiologists independently reviewed each MRCP exam and three signs were assessed: (1) the "duct-interrupted" sign, deemed positive for PDAC if the duct within the mass demonstrated complete interruption with upstream dilation; (2) the "corona" sign, considered positive for PDAC if dilated side-branches were located exclusively outside the mass; and (3) the "attraction" sign, deemed positive for IPP if the dilated common bile duct showed attraction and angulation towards the mass. Sensitivity, specificity, and positive and negative predictive values of the signs were calculated, as well as interobserver agreement.

RESULTS

Out of 53 masses, 17 (32%) were PDAC and 36 (68%) were IPP. Sensitivity, specificity, and positive and negative predictive values of the "duct-interrupted" sign to differentiate between PDAC from IPP for the three readers were 29-53%, 89-95%, 56-82% and 73-81%, respectively (κ = 0.41); for the "corona" sign, they were 29-53%, 81-100%, 56-100%, and 75-78%, respectively (κ = 0.4), and for the "attraction" sign, they were 20-25%, 71-82%, 64-75%, and 31-34%, respectively (κ = 0.54).

CONCLUSION

The "duct-interrupted" and "corona" MRCP signs have high specificity for diagnosing PDAC, while the "attraction" sign has good specificity for identifying IPP.

Flow-through Omental Flap for Vascularized Lymph Node Transfer: A Novel Surgical Approach for Delayed Lymphatic Reconstruction

The vascularized omental free flap has been described as a reliable option for the treatment of peripheral lymphedema. However, the flap has been associated with venous hypertension which may require venous supercharging or intra-flap arteriovenous fistula creation to offload the arterial inflow. The aim of this study is to introduce and present our experience using a flow-through omental flap as a novel approach to optimize flap hemodynamics. A retrospective review of a prospectively maintained quality improvement database was performed. Seven consecutive patients with unilateral breast cancer-related lymphedema (BCRL) who underwent delayed lymphatic reconstruction using a flow-through omental free flap were identified. In all patients, the right gastroepiploic artery and vein were anastomosed to the proximal end of the radial artery and to one venae comitante, respectively. An anastomosis of the distal end of the radial artery to the left gastroepiploic artery was performed. The flap was then supercharged by anastomosing the left gastroepiploic vein to the cephalic or basilic vein. There were no flap losses or other surgical complications. A distinct advantage of this inset includes the ability to moderate the arterial in-flow to the omental flap to avoid an inflow-outflow mismatch and alleviate venous hypertension. Further study is needed to validate this technique in a larger study sample with longer follow-up.

Pancreatic perfusion modulation following glucose stimulation assessed by noninvasive arterial spin labeling (ASL) MRI

BACKGROUND

More than 100 million adults in the US suffer from prediabetes or type-2 diabetes. Noninvasive imaging of pancreas endocrine function might provide a surrogate marker of β-cell functional integrity loss linked to this disease.

PURPOSE

To noninvasively assess pancreatic blood-flow modulation following a glucose challenge using arterial spin labeling (ASL) MRI.

STUDY TYPE

Prospective.

SUBJECTS

Fourteen adults (30 ± 7 years old, 3M/11F, body mass index [BMI] = 24 ± 3 kg.m^-2 ).

FIELD STRENGTH/SEQUENCE

3T MRI / background-suppressed pseudocontinuous PCASL preparation with single-shot fast-spin-echo (FSE) readout before and after an oral glucose challenge using either fruit juice (n = 7) or over-the-counter glucose gel (n = 7).

ASSESSMENT

Subjects were fasting prior to initiation of oral stimulation, then dynamic perfusion measurements were performed every 2 minutes for 30 minutes. We quantified absolute blood flow at each timepoint.

STATISTICAL TESTS

Repeated-measures analysis of variance (ANOVA) followed by paired t-tests to assess for a significant effect of glucose challenge on measured perfusion.

RESULTS

Measured basal blood flow was 187 ± 53 mL/100g/min. A significant blood flow increase of +38 ± 26% was observed 10 minutes poststimulation (P < 0.05) and continuing until the end of the experiment. The gel stimulation provided the most consistent results, with an early rise followed by an additional later increase consistent with the known pancreatic insulin response to elevated blood glucose. Across-subject variations in blood flow increase were partially attributable to basal flow, with a negative correlation of r = -0.84 between basal and maximal relative flow increase in the gel group.

DATA CONCLUSION

ASL can be used to measure pancreatic flow in response to a glucose challenge, which could be linked to insulin release and secretion. This paradigm might be useful to characterize disorders of glucose regulation.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:854-860.

Vaginal spindle cell epithelioma: A first complete MRI and histopathologic description

Spindle cell epithelioma of the vagina is a benign entity with fewer than sixty cases described in the literature, and only two with limited imaging findings, since the early 1950s. Early pathology literature suggested the lesions were mixed tumors of myoepithelial origin, but subsequent studies have found relatively few immunohistochemical characteristics in common with other mixed cell tumors. More recently, Mullerian, urogenital sinus epithelial, and pluripotential cell origins have been proposed. Given lesion rarity and a typical lack of imaging before excision, the imaging appearance of vaginal spindle cell epitheliomas has not been fully described in the radiology literature, and without comprehensive pathology correlation. The authors describe a case of spindle cell epithelioma in a 54-year-old woman which was incidentally discovered on MRI performed for uterine fibroid embolization planning. Pathology and immunohistochemistry confirmed the diagnosis.

A Practical Guide to MR Imaging Safety: What Radiologists Need to Know

Magnetic resonance (MR) imaging can provide critical diagnostic and anatomic information while avoiding the use of ionizing radiation, but it has a unique set of safety risks associated with its reliance on large static and changing magnetic fields, high-powered radiofrequency coil systems, and exogenous contrast agents. It is crucial for radiologists to understand these risks and how to mitigate them to protect themselves, their colleagues, and their patients from avoidable harm and to comply with safety regulations at MR imaging sites. Basic knowledge of MR imaging physics and hardware is necessary for radiologists to understand the origin of safety regulations and to avoid common misconceptions that could compromise safety. Each of the components of the MR imaging unit can be a factor in injuries to patients and personnel. Safety risks include translational force and torque, projectile injury, excessive specific absorption rate, burns, peripheral neurostimulation, interactions with active implants and devices, and acoustic injury. Standards for MR imaging device safety terminology were first issued in 2005 and are required by the U.S. Food and Drug Administration, with devices labeled as "MR safe," "MR unsafe," or "MR conditional." MR imaging contrast agent safety is also discussed. Additional technical and safety policies relate to pediatric, unconscious, incapacitated, or pregnant patients and pregnant imaging personnel. Division of the MR imaging environment into four distinct, clearly labeled zones--with progressive restriction of entry and increased supervision for higher zones--is a mandatory and key aspect in avoidance of MR imaging-related accidents. All MR imaging facilities should have a documented plan to handle emergencies within zone IV, including cardiac arrest or code, magnet quench, and fires. Policies from the authors' own practice are provided for additional reference. Online supplemental material is available for this article.

Gallbladder splenosis: a hereto unreported mimicker of a gallbladder neoplasm

Splenosis is a completely benign entity that can mimic a primary mass or metastasis. Herein we report the first known case of gallbladder splenosis in a 49-year-old woman with an extensive surgical and medical history. Cross-sectional computed tomography and MRI demonstrated a single mass arising from the gallbladder fundus. Revelation of splenectomy, confirmed to be traumatic from medical records, raised the suspicion for splenosis. The diagnosis was confirmed with a Technecium-99m-labeled heat-damaged blood cell scan, considered the gold-standard for detection of ectopic splenic tissue.

Resident iPad use: has it really changed the game?

PURPOSE

The purpose of this study was to assess residents' usage patterns and opinions of the iPad as a tool for radiology education and clinical practice at an academic medical center.

METHODS

All 38 radiology residents in our radiology program (postgraduate years 2 to 5) were provided with iPad 2 tablets and subscriptions to e-Anatomy and STATdx. After 6 months of device use, residents were surveyed to assess their opinions regarding the technology as a tool for education and clinical practice.

RESULTS

A total of 36 residents (95%) completed the survey. Eighty-six percent reported daily iPad use. Radiology-specific applications, particularly e-Anatomy, were used weekly or daily by 88% of respondents. Most preferred to read journal articles on the iPad (70%), but the number of respondents preferring to read textbooks on the iPad (48.5%) compared with the traditional bound form (48.5%) was evenly divided. Residents were also divided on the clinical utility of the iPad. Most had not used the iPad to view radiologic examinations (75%). Fewer than half (47%) used their iPads during readout. Finally, only 12% had used the iPad to edit dictated reports.

CONCLUSIONS

The iPad has generated excitement within the radiology community, particularly among resident educators, who are increasingly recognizing the unique needs of "millennial learners." This study showed that the majority of residents at the authors' institution have incorporated the iPad as an educational tool and use it as a learning aid. Incorporation of the iPad into clinical workflow has been less pronounced.

[18F]-Fluorodeoxyglucose positron emission tomography in children with neurofibromatosis type 1 and plexiform neurofibromas: correlation with malignant transformation

The objective of this study was to investigate the predictive value of [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) in detecting malignant transformation of plexiform neurofibromas in children with neurofibromatosis type 1 (NF1). An electronic search of the medical records was performed to determine patients with NF1 who had undergone FDG-PET for plexiform neurofibroma between 2000 and 2011. All clinical, radiologic, pathology information and operative reports were reviewed. Relationship between histologic diagnosis, radiologic features and FDG-PET maximum standardized uptake value (SUV(max)) was evaluated. This study was approved by the Institutional Review Board of our institution. 1,450 individual patients were evaluated in our Multidisciplinary Neurofibromatosis Program, of whom 35 patients underwent FDG-PET for suspected MPNST based on change or progression of clinical symptoms, or MRI findings suggesting increased tumor size. Twenty patients had concurrent pathologic specimens from biopsy/excision of 27 distinct lesions (mean age 14.9 years). Pathologic interpretation of these specimens revealed plexiform and atypical plexiform neurofibromas (n = 8 each), low grade MPNST (n = 2), intermediate grade MPNST (n = 4), high grade MPNST (n = 2), GIST (n = 1) and non-ossifying fibroma (n = 1). SUV(max) of plexiform neurofibromas (including typical and atypical) was significantly different from MPNST (2.49 (SD = 1.50) vs. 7.63 (SD = 2.96), p < 0.001). A cutoff SUV(max) value of 4.0 had high sensitivity and specificity of 1.0 and 0.94 to distinguish between PN and MPNST. FDG-PET can be helpful in predicting malignant transformation in children with plexiform neurofibromas and determining the need for biopsy and/or surgical resection.

Posture-dependent human 3He lung imaging in an open-access MRI system: initial results

RATIONALE AND OBJECTIVES

The human lung and its functions are extremely sensitive to orientation and posture, and debate continues as to the role of gravity and the surrounding anatomy in determining lung function and heterogeneity of perfusion and ventilation. However, study of these effects is difficult. The conventional high-field magnets used for most hyperpolarized (3)He magnetic resonance imaging (MRI) of the human lung, and most other common radiologic imaging modalities including positron emission tomography and computed tomography, restrict subjects to lying horizontally, minimizing most gravitational effects.

MATERIALS AND METHODS

In this article, we review the motivation for posture-dependent studies of human lung function and present initial imaging results of human lungs in the supine and vertical body orientations using inhaled hyperpolarized (3)He gas and an open-access MRI instrument. The open geometry of this MRI system features a "walk-in" capability that permits subjects to be imaged in vertical and horizontal positions and potentially allows for complete rotation of the orientation of the imaging subject in a two-dimensional plane.

RESULTS

Initial results include two-dimensional lung images acquired with approximately 4 x 8 mm in-plane resolution and three-dimensional images with approximately 2-cm slice thickness.

CONCLUSIONS

Effects of posture variation are observed, including posture-related effects of the diaphragm and distension of the lungs while vertical.

Interstitial gas and density segregation of vertically vibrated granular media

We report experimental studies of the effect of interstitial gas on mass-density segregation in a vertically vibrated mixture of equal-sized bronze and glass spheres. Sufficiently strong vibration in the presence of interstitial gas induces vertical segregation into sharply separated bronze and glass layers. We find that the segregated steady state (i.e., bronze or glass layer on top) is a sensitive function of gas pressure and viscosity, as well as vibration frequency and amplitude. In particular, we identify distinct regimes of behavior that characterize the change from bronze-on-top to glass-on-top steady state.

A System for Open-Access He Human Lung Imaging at Very Low Field

We describe a prototype system built to allow open-access very-low-field MRI of human lungs using laser-polarized (3)He gas. The system employs an open four-coil electromagnet with an operational B(0) field of 4 mT, and planar gradient coils that generate gradient fields up to 0.18 G/cm in the x and y direction and 0.41 G/cm in the z direction. This system was used to obtain (1)H and (3)He phantom images and supine and upright (3)He images of human lungs. We include discussion on challenges unique to imaging at 50 -200 kHz, including noise filtering and compensation for narrow-bandwidth coils.

3He lung imaging in an open access, very-low-field human magnetic resonance imaging system

The human lung and its functions are extremely sensitive to gravity; however, the conventional high-field magnets used for most laser-polarized (3)He MRI of the human lung restrict subjects to lying horizontally. Imaging of human lungs using inhaled laser-polarized (3)He gas is demonstrated in an open-access very-low-magnetic-field (<5 mT) MRI instrument. This prototype device employs a simple, low-cost electromagnet, with an open geometry that allows variation of the orientation of the imaging subject in a two-dimensional plane. As a demonstration, two-dimensional lung images were acquired with 4-mm in-plane resolution from a subject in two orientations: lying supine and sitting in a vertical position with one arm raised. Experience with this prototype device will guide optimization of a second-generation very-low-field imager to enable studies of human pulmonary physiology as a function of subject orientation.

Interaction between light-dark cycles and circadian rhythm on sleep and wakefulness in albino rats

This study investigated the role of the circadian phase in modulating the effect of short light-dark cycles (LDc) on sleep and wakefulness. Six male albino rats of the Sprague-Dawley strain were implanted with electrodes for standard electrophysiological recordings performed during baseline (12 - 12 h LDc), short LDc treatment, and recovery (12 - 12 h LDc) for 4 days each. In the short LDc treatment, 15 - 15 min LDc were applied, respectively, in mid-periods of inactive and active phases to maintain an entrained circadian rhythm. The results showed that the 15 - 15 min LD ratio of both non-rapid eye movement sleep (NREM) and paradoxical sleep (PS) did not vary with the circadian phase. In contrast, changes in both the NREM and PS amounts in the short LDc treatment varied with the circadian phase. It is argued in the Discussion section that the circadian phase-related changes in the sleep amount did not result from the circadian rhythm effect but from the interactions between the habitual 24 h lighting schedule and the habitual LD distribution of the sleep and wakefulness amounts. On the other hand, this study found that both waking (W) and PS response to short LDc varied with time courses. The 15 min dark period strongly enhanced the W time only when it occurred for the first time in the inactive phase while it consistently facilitated PS across the remaining time periods in both the active and inactive phases. Furthermore, a residual effect of short LDc on PS was revealed in this study. Compared to the baseline, the 12 - 12 h LD ratio of PS was significantly decreased during recovery compared to the short LDc treatment.

Selection of valid and reliable EEG features for predicting auditory and visual alertness levels

A selection procedure with three rules, high efficiency, low individual variability, and low redundancy, was developed to screen electroencephalogram (EEG) features for predicting behavioral alertness levels. A total of 24 EEG features were derived from temporal, frequency spectral, and statistical analyses. Behavioral alertness levels were quantified by correct rates of performance on an auditory and a visual vigilance task, separately. In the auditory task study, a subset of three EEG features, the relative spectral amplitudes in the alpha (alpha%, 8-13 Hz) and theta (theta%, 4-8 Hz) bands, and the mean frequency of the EEG spectrum (MF), was found to be the best combination for predicting the auditory alertness level. In the visual task study, the mean frequency of the beta band (Fbeta, 13-32 Hz) was the only EEG feature selected. The application of an averaging subwindow procedure within a moving time window to EEG analysis increased the predictive power of EEG features and decreased the disturbing effect of movement artifacts on the EEG data.

Staurosporine inhibits the proliferation, alters the cell cycle distribution and induces apoptosis in HT-29 human colon adenocarcinoma cells

Staurosporine (ST), a potent inhibitor of protein kinase C (PKC), was evaluated for its effect on the proliferation of HT-29 colon adenocarcinoma cells; PKC is associated with increased colon cell proliferation. ST inhibited cell proliferation in a time- and concentration-dependent manner by up to 90%. It also blocked the G2/M phase of the cell cycle and induced classical apoptosis (sub-diploid peak on flow cytometry, DNA ladder, and typical morphological changes). The kinetics of these changes suggest that low ST concentrations (2-20 nM) may act via a different mechanism from higher (100-1000 nM) ones. The role of ST, which is currently evaluated as an antitumor agent, in colon cancer requires further evaluation.

The anti-proliferative effect of sulindac and sulindac sulfide on HT-29 colon cancer cells: alterations in tumor suppressor and cell cycle-regulatory proteins

Nonsteroidal anti-inflammatory drugs lower the incidence of and mortality from colon cancer. Sulindac reduces the number and size of polyps in patients with familial adenomatous polyposis. We have shown that sulindac and sulindac sulfide reversibly reduce the proliferation rate of HT-29 colon cancer cells, alter their morphology, induce them to accumulate in the G0/G1 phase of the cell cycle, and sulindac sulfide induces cell death by apoptosis. In this study we confirmed that sulindac and sulindac sulfide prevent HT-29 cells from progressing from the G0/G1 into the S phase. This block in cell cycle progression is associated with an initial rise, then an abrupt decrease in the levels of p34cdc2 protein. Sulindac and sulindac sulfide decrease the levels of mitotic cyclins, induce the levels of p21WAF-1/cip1, and reduce the total levels of pRB, with a relative increase in the amount of the underphosphorylated form of pRB in a time- and concentration-dependent manner. In addition, these compounds reduce the levels of mutant p53. These responses are not associated with intestinal cell differentiation and occur independent of the ability of these compounds to induce apoptosis. We conclude that sulindac and sulindac sulfide reduce the levels of major components of the molecular cell cycle machinery and alter the levels of several tumor suppressor proteins in a manner consistent with cell cycle quiescence. These mechanisms may be operative in vivo to account, in part, for the anti-neoplastic effects of these compounds.

Sleep deprivation in the rat: XX. Differences in wake and sleep temperatures during recovery

We examined the relationship between wake and sleep peritoneal temperature (T(ip)) during recovery from short-term (five rats, 5 days of deprivation) and long-term (nine rats, 14-21 days) total sleep deprivation (TSD). Mammalian body temperature normally declines in the passage from wakefulness to sleep. Recovery from TSD featured reductions of the typical wake-sleep T(ip) differences. Previous studies from our laboratory have shown that chronic TSD in the rat produces a progressive rise in energy production and an initial rise in wake T(ip), followed by a later fall in T(ip) to below baseline that becomes more acute as death becomes imminent. During recovery from both short-term TSD (wherein pre-recovery wake T(ip) was still above baseline) and long-term TSD (wherein pre-recovery wake T(ip) had fallen to below baseline), wake T(ip) and energy production quickly returned towards baseline. On the first recovery day, both short- and long-term TSD rats showed mean non-rapid eye movement (NREM) and paradoxical sleep (PS) T(ip) values that were slightly, although not significantly, above mean wake T(ip). In short-term TSD rats, wake-NREM and wake-PS T(ip) differences were reduced from baseline significantly (p < 0.0025) on the first recovery day and nonsignificantly on the remaining three recovery days. In long-term TSD rats, wake-NREM and wake-PS T(ip) differences were significantly (p < 0.001) reduced from baseline on the first four recovery day block. On the last four recovery day block, wake-sleep T(ip) differences tended to return toward baseline. Hypothalamic wake-sleep temperature differences in long-term TSD rats showed similar reductions during recovery. The reduction of wake-sleep temperature differences in recovery does not support either energy reduction or cooling functions for sleep.

Sulindac sulfide, an aspirin-like compound, inhibits proliferation, causes cell cycle quiescence, and induces apoptosis in HT-29 colon adenocarcinoma cells

Nonsteroidal antiinflammatory drugs (NSAIDs), have cancer preventive and tumor regressive effects in the human colon. They lower the incidence of and mortality from colorectal cancer and sulindac reduces the number and size of polyps in patients with familial adenomatous polyposis. We studied the effect of sulindac, and its metabolite sulindac sulfide, on the proliferation of HT-29 colon adenocarcinoma cells. Both compounds reduced the proliferation rate of these cells, changed their morphology, and caused them to accumulate in the G0/G1 phase of the cell cycle. These responses were time- and concentration-dependent and reversible. In addition, these compounds reduced the level and activity of several cyclin-dependent kinases (cdks), which regulate cell cycle progression. Sulindac and sulindac sulfide also induced apoptosis in these cells at concentrations that affected their proliferation, morphology, and cell cycle phase distribution. Sulindac sulfide was approximately sixfold more potent than sulindac in inducing these cellular responses. Our results indicate that inhibition of cell cycle progression and induction of apoptotic cell death contribute to the anti-proliferative effects of sulindac and sulindac sulfide in HT-29 cells. These findings may be relevant to the cancer preventive and tumor regressive effects of these compounds in humans.