Comparing Magnetic Resonance Imaging and Prostate-Specific Membrane Antigen-Positron Emission Tomography for Prediction of Extraprostatic Extension of Prostate Cancer and Surgical Guidance: A Prospective Nonrandomized Clinical Trial.

PURPOSE: Survivors of surgically managed prostate cancer may experience urinary incontinence and erectile dysfunction. Our aim was to determine if 68Ga-prostate-specific membrane antigen-11 positron emission tomography CT (PSMA-PET) in addition to multiparametric (mp) MRI scans improved surgical decision-making for nonnerve-sparing or nerve-sparing approach. MATERIALS AND METHODS: We prospectively enrolled 50 patients at risk for extraprostatic extension (EPE) who were scheduled for prostatectomy. After mpMRI and PSMA-PET images were read for EPE prediction, surgeons prospectively answered questionnaires based on mpMRI and PSMA-PET scans on the decision for nerve-sparing or nonnerve-sparing approach. Final whole-mount pathology was the reference standard. Sensitivity, specificity, positive predictive value, negative predictive value, and receiver operating characteristic curves were calculated and McNemar's test was used to compare imaging modalities. RESULTS: The median age and PSA were 61.5 years and 7.0 ng/dL. The sensitivity for EPE along the posterior neurovascular bundle was higher for PSMA-PET than mpMRI (86% vs 57%, P = .03). For MRI, the specificity, positive predictive value, negative predictive value, and area under the curve for the receiver operating characteristic curves were 77%, 40%, 87%, and 0.67, and for PSMA-PET were 73%, 46%, 95%, and 0.80. PSMA-PET and mpMRI reads differed on 27 nerve bundles, with PSMA-PET being correct in 20 cases and MRI being correct in 7 cases. Surgeons predicted correct nerve-sparing approach 74% of the time with PSMA-PET scan in addition to mpMRI compared to 65% with mpMRI alone (P = .01). CONCLUSIONS: PSMA-PET scan was more sensitive than mpMRI for EPE along the neurovascular bundles and improved surgical decisions for nerve-sparing approach. Further study of PSMA-PET for surgical guidance is warranted in the unfavorable intermediate-risk or worse populations. CLINICALTRIALS.GOV IDENTIFIER: NCT04936334.

Burden of fatty liver and hepatic fibrosis in persons with HIV: A diverse cross-sectional US multicenter study.

BACKGROUND AIMS: The current prevalence of fatty liver disease (FLD) due to alcohol-associated (AFLD) and nonalcoholic (NAFLD) origins in US persons with HIV (PWH) is not well defined. We prospectively evaluated the burden of FLD and hepatic fibrosis in a diverse cohort of PWH. APPROACH RESULTS: Consenting participants in outpatient HIV clinics in 3 centers in the US underwent detailed phenotyping, including liver ultrasound and vibration-controlled transient elastography for controlled attenuation parameter and liver stiffness measurement. The prevalence of AFLD, NAFLD, and clinically significant and advanced fibrosis was determined. Univariate and multivariate logistic regression models were used to evaluate factors associated with the risk of NAFLD. Of 342 participants, 95.6% were on antiretroviral therapy, 93.9% had adequate viral suppression, 48.7% (95% CI 43%-54%) had steatosis by ultrasound, and 50.6% (95% CI 45%-56%) had steatosis by controlled attenuation parameter ≥263 dB/m. NAFLD accounted for 90% of FLD. In multivariable analysis, old age, higher body mass index, diabetes, and higher alanine aminotransferase, but not antiretroviral therapy or CD4 + cell count, were independently associated with increased NAFLD risk. In all PWH with fatty liver, the frequency of liver stiffness measurement 8-12 kPa was 13.9% (95% CI 9%-20%) and ≥12 kPa 6.4% (95% CI 3%-11%), with a similar frequency of these liver stiffness measurement cutoffs in NAFLD. CONCLUSIONS: Nearly half of the virally-suppressed PWH have FLD, 90% of which is due to NAFLD. A fifth of the PWH with FLD has clinically significant fibrosis, and 6% have advanced fibrosis. These data lend support to systematic screening for high-risk NAFLD in PWH.

Direct comparison and reproducibility of two segmentation methods for multicompartment dosimetry: round robin study on radioembolization treatment planning in hepatocellular carcinoma.

PURPOSE: Investigate reproducibility of two segmentation methods for multicompartment dosimetry, including normal tissue absorbed dose (NTAD) and tumour absorbed dose (TAD), in hepatocellular carcinoma patients treated with yttrium-90 (90Y) glass microspheres. METHODS: TARGET was a retrospective investigation in 209 patients with < 10 tumours per lobe and at least one tumour ≥ 3 cm ± portal vein thrombosis. Dosimetry was compared using two distinct segmentation methods: anatomic (CT/MRI-based) and count threshold-based on pre-procedural 99mTc-MAA SPECT. In a round robin substudy in 20 patients with ≤ 5 unilobar tumours, the inter-observer reproducibility of eight reviewers was evaluated by computing reproducibility coefficient (RDC) of volume and absorbed dose for whole liver, whole liver normal tissue, perfused normal tissue, perfused liver, total perfused tumour, and target lesion. Intra-observer reproducibility was based on second assessments in 10 patients ≥ 2 weeks later. RESULTS: 99mTc-MAA segmentation calculated higher absorbed doses compared to anatomic segmentation (n = 209), 43.9% higher for TAD (95% limits of agreement [LoA]: - 49.0%, 306.2%) and 21.3% for NTAD (95% LoA: - 67.6%, 354.0%). For the round robin substudy (n = 20), inter-observer reproducibility was better for anatomic (RDC range: 1.17 to 3.53) than 99mTc-MAA SPECT segmentation (1.29 to 7.00) and similar between anatomic imaging modalities (CT: 1.09 to 3.56; MRI: 1.24 to 3.50). Inter-observer reproducibility was better for larger volumes. Perfused normal tissue volume RDC was 1.95 by anatomic and 3.19 by 99mTc-MAA SPECT, with corresponding absorbed dose RDC 1.46 and 1.75. Total perfused tumour volume RDC was higher, 2.92 for anatomic and 7.0 by 99mTc-MAA SPECT with corresponding absorbed dose RDC of 1.84 and 2.78. Intra-observer variability was lower for perfused NTAD (range: 14.3 to 19.7 Gy) than total perfused TAD (range: 42.8 to 121.4 Gy). CONCLUSION: Anatomic segmentation-based dosimetry, versus 99mTc-MAA segmentation, results in lower absorbed doses with superior reproducibility. Higher volume compartments, such as normal tissue versus tumour, exhibit improved reproducibility. TRIAL REGISTRATION: NCT03295006.

CT texture analysis of pancreatic cancer.

OBJECTIVES: We investigated the value of CT texture analysis (CTTA) in predicting prognosis of unresectable pancreatic cancer. METHODS: Sixty patients with unresectable pancreatic cancers at presentation were enrolled for post-processing with CTTA using commercially available software (TexRAD Ltd, Cambridge, UK). The largest cross-section of the tumour on axial CT was chosen to draw a region-of-interest. CTTA parameters (mean value of positive pixels (MPP), kurtosis, entropy, skewness), arterial and venous invasion, metastatic disease and tumour size were correlated with overall and progression-free survivals. RESULTS: The median overall and progression-free survivals of cohort were 13.3 and 7.8 months, respectively. On multivariate Cox proportional hazard regression analysis, presence of metastatic disease at presentation had the highest association with overall survival (p = 0.003-0.05) and progression-free survival (p < 0.001 to p = 0.004). MPP at medium spatial filter was significantly associated with poor overall survival (p = 0.04). On Kaplan-Meier survival analysis of CTTA parameters at medium spatial filter, MPP of more than 31.625 and kurtosis of more than 0.565 had significantly worse overall survival (p = 0.036 and 0.028, respectively). CONCLUSIONS: CTTA features were significantly associated with overall survival in pancreas cancer, particularly in patients with non-metastatic, locally advanced disease. KEY POINTS: • CT texture analysis is easy to perform on contrast-enhanced CT. • CT texture analysis can determine prognosis in patients with unresectable pancreas cancer. • The best predictors of poor prognosis were high kurtosis and MPP.

Contrast-enhanced ultrasound of the transplant pancreas in the post-operative setting.

BACKGROUND/OBJECTIVES: Vascular thrombosis is the most common cause of early graft loss after transplantation. Routine grayscale and Doppler ultrasound frequently fail to adequately visualize vascular compromise. Contrast-enhanced ultrasound is a novel approach to identifying these complications. METHODS: This was a prospective study of 22 consecutive patients who received pancreas transplant at our institution between 2017 and 2018. All allografts were implanted with systemic venous and enteric exocrine drainage. Perfusion was assessed in the immediate post-operative period using grayscale, Doppler, and contrast-enhanced ultrasound. Imaging findings were compared between those who required surgical re-intervention and those who did not in order to evaluate for differences in perfusion. RESULTS: Of the 22 transplants, 15 did not require surgical re-intervention and were considered normal. These allografts demonstrated prompt and uniform enhancement, with washout usually by 90 seconds. All patients who had abnormal CEUS underwent re-exploration. Perfusion was acceptable or restored in all cases. Two patients ultimately required allograft pancreatectomy. Two patients had normal glands, and the remaining 3 grafts were salvaged following intervention. CONCLUSIONS: Contrast-enhanced ultrasound provides rapid evaluation of allograft perfusion following pancreas transplantation. The differences in perfusion provide a novel way of evaluating for complications in the immediate post-transplant period.

Can functional parameters from hepatobiliary phase of gadoxetate MRI predict clinical outcomes in patients with cirrhosis?

OBJECTIVES: To determine the value of quantitative parameters of gadoxetate-enhanced magnetic resonance imaging (MRI) in predicting prognosis in patients with cirrhosis. METHODS: A cohort of 63 cirrhotic patients who had gadoxetate MRI and 2-year clinical follow-up was enrolled. Enhancement ratio (ER), contrast enhancement index (CEI) and contrast enhancement spleen index (CES) were calculated. The usefulness of these parameters and clinical scores, such as Child-Pugh score (CPS) and model for end stage liver disease (MELD), in predicting adverse outcomes, such as variceal bleeding (VB), hepatic encephalopathy (HE) and mortality at 2 years were evaluated. RESULTS: Fifteen, 31 and 27 patients, respectively, had VB, HE and mortality within 2 years. The ER at 15 min (ER 15) and CES at 20 min (CES 20) were found to be the best MRI predictors. Areas under the receiver operating characteristic curve (AUC) for predicting VB were 0.785, 0.729, 0.673, 0.714, respectively, for ER 15, CES 20, CPS and MELD scores. ER 15 of less than 48 had sensitivity of 96% and specificity of 84% for predicting onset of HE within 2 years. CONCLUSIONS: In patients with cirrhosis, ER 15 or CES 20 were equivalent or better predictors of major morbidity and mortality compared with commonly used clinical scores. KEY POINTS: • Gadoxetate parameters may identify cirrhotic patients at risk of adverse events. • Gadoxetate parameters usually show superior predictive values compared to clinical scores. • CES 20 score is associated with risk of mortality within 2 years.

Correlation of Technetium-99m Macroaggregated Albumin and Yttrium-90 Glass Microsphere Biodistribution in Hepatocellular Carcinoma: A Retrospective Review of Pretreatment Single Photon Emission CT and Posttreatment Positron Emission Tomography/CT.

PURPOSE: To evaluate whether technetium-99 (99mTc)-labeled macroaggregated albumin (MAA) can predict subsequent yttrium-90 (90Y) distribution and imaging response in patients with hepatocellular carcinoma (HCC). MATERIALS: Retrospective review was performed of records of 83 patients with HCC who underwent 90Y glass microsphere radioembolization with 99mTc-MAA single photon emission computed tomography (SPECT) and 90Y positron emission tomography (PET)/CT between January 2013 and December 2014. Images were fused to segment the whole liver normal tissue (WLNT) and the largest tumors. Fused images were reviewed and analyzed for comparison of absorbed dose (AD) to tumors and WLNT as calculated from 99mTc-MAA SPECT and from 90Y PET/CT, subjective imaging comparison of 99mTc-MAA SPECT and 90Y PET for tumors and WLNT, and correlation of tumoral AD with response on follow-up CT. RESULTS: Final analysis included 73 and 63 patients for WLNT and tumor 99mTc-MAA/90Y correlation, respectively, and 62 patients for AD vs response. 99mTc-MAA/90Y limit of agreement for each reviewer was viewed as clinically acceptable only for WLNT (-15 to 15 Gy). AD interreviewer variability was clinically acceptable for WLNT but was too broad for tumor. Mean tumor AD for objective response (78%) was 313 Gy vs 234 Gy for nonresponders. No threshold was found between tumor AD and response (P > .1). Catheter mismatch between 99mTc-MAA and 90Y had a direct impact on AD mismatch between the 2 image sets. CONCLUSIONS: 99mTc-MAA was found to be a poor surrogate to quantitatively predict subsequent 90Y AD to hepatocellular tumors. 99mTc-MAA distribution correlated with 90Y distribution in the normal hepatic parenchyma.

The Presence of Portal Vein Thrombosis Alters the Classic Enhancement Associated with Diagnosis of Hepatocellular Carcinoma.

AIMS: To determine whether the presence of portal vein thrombosis (PVT) where venous flow within the liver may be altered may delay the diagnosis of HCC and be associated with more advanced disease. We characterized the incidence and imaging characteristics of patients diagnosed with hepatocellular carcinoma in a cohort of patients with PVT compared with those without PVT. METHODS: This is a single-center retrospective study of a subset of HCC patients who underwent dynamic imaging for HCC screening and were found to have PVT. Data abstracted included demographic data, TNM stage, number/type of scans, AFP level, MELD score, and time to diagnosis. RESULTS: Eighty-two patients newly diagnosed with HCC on screening were reviewed, of which 37 % (30/82) were found to have portal vein thrombosis. Patients with PVT had higher rates of atypical imaging associated with HCC compared with those without PVT (83 vs 56 %, p = 0.01) and had lower rates of portal venous washout (23 % vs 50 %, p = 0.018). Patients with PVT and HCC were also diagnosed at later TNM stage than those without PVT (70 vs 23 %, p < 0.001) and were significantly less likely to receive orthotopic liver transplant (3.6 vs 42 %, p < 0.001). Fourteen patients had preexisting PV clot without HCC; 16 developed PVT during screening or at diagnosis. Those with preexisting PVT were older (63. vs 55 years) and had higher rates of diagnosis of HCC using MRI (79 vs 21 % with CT, p = 0.01), compared with those without preexisting PVT. CONCLUSION: The presence of PVT found on dynamic imaging was associated with advanced stage of HCC at the time of diagnosis. Clinicians should have a high suspicion for HCC diagnosis in new liver lesions with atypical enhancement in the setting of PVT. In this setting, MRI was more frequently associated with HCC diagnosis.

Evaluation of 11C-acetate and 18F-FDG PET/CT in mouse multidrug resistance gene-2 deficient mouse model of hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) remains a global health problem with unique diagnostic and therapeutic challenges, including difficulties in identifying the highest risk patients. Previous work from our lab has established the murine multidrug resistance-2 mouse (MDR2) model of HCC as a reasonable preclinical model that parallels the changes seen in human inflammatory associated HCC. The purpose of this study is to evaluate modalities of PET/CT in MDR2(-/-) mice in order to facilitate therapeutic translational studies from bench to bedside. METHODS: 18F-FDG and 11C-acetate PET/CT was performed on 12 m MDR2(-/-) mice (n = 3/tracer) with HCC and 12 m MDR2(-/+) control mice (n = 3/tracer) without HCC. To compare PET/CT to biological markers of HCC and cellular function, serum alpha-fetoprotein (AFP), lysophosphatidic acid (LPA), cAMP and hepatic tumor necrosis factor α (TNFα) were quantified in 3-12 m MDR2(-/-) (n = 10) mice using commercially available ELISA analysis. To translate results in mice to patients 11C-acetate PET/CT was also performed in 8 patents suspected of HCC recurrence following treatment and currently on the liver transplant wait list. RESULTS: Hepatic18F-FDG metabolism was not significantly increased in MDR2(-/-) mice. In contrast, hepatic 11C-acetate metabolism was significantly elevated in MDR2(-/-) mice when compared to MDR2(-/+) controls. Serum AFP and LPA levels increased in MDR2(-/-) mice contemporaneous with the emergence of HCC. This was accompanied by a significant decrease in serum cAMP levels and an increase in hepatic TNFα. In patients suspected of HCC recurrence there were 5 true positives, 2 true negatives and 1 suspected false 11C-acetate negative. CONCLUSIONS: Hepatic 11C-acetate PET/CT tracks well with HCC in MDR2(-/-) mice and patients with underlying liver disease. Consequently 11C-acetate PET/CT is well suited to study (1) HCC emergence/progression in patients and (2) reduce animal numbers required to study new chemotherapeutics in murine models of HCC.

Value of magnetic resonance imaging in evaluating the pancreatic allograft transplant complications.

PURPOSE: To retrospectively investigate the value of magnetic resonance imaging (MRI) in detecting complications following pancreas transplant. MATERIALS AND METHODS: Institutional review board approved this retrospective HIPAA-compliant study and waived informed patient consent. We identified all allograft pancreas transplant patients at our institution from 2001 to January 2014 who had all pertinent post-transplant imaging and clinical data available. Transplant type was documented. Patients were divided into two groups according to post-transplant period (group A; <12 months, group B; ≥12 months). We evaluated the parenchymal enhancement using contrast-enhanced MRI of the allograft and determined the mean percentage of parenchymal enhancement (MPPE) overall and in various abnormalities, the vessel patency, any peripancreatic fluid collection, and the ductal anatomy. We correlated these with clinical results using t test, χ (2), and Fisher's exact test; p < 0.05 was considered significant. RESULTS: 51 patients (34 male, mean age 43.7 years) were identified, 28 (55%) of whom had abnormal imaging findings; transplant rejection-related necrosis (n = 7), fluid collections (n = 7), vascular stenosis (n = 4), isolated venous thromboses (n = 3), acute pancreatitis (n = 3), pancreatic and peripancreatic abscesses (n = 2), pseudoaneurysm (n = 1), and small-bowel obstruction (n = 1). Pre vs. post-contrast pancreatic MPPE at 1 min was 120% in the normal allografts and 115% in the allografts with pancreatitis and without necrosis (p > 0.05). MPPE at 1 min was only 9% in the allografts rejections with necrosis/infarction. More complications were found in group A than group B (p < 0.05). CONCLUSIONS: Contrast-enhanced MRI is useful for the non-invasive assessment of pancreas transplant complications.

Microsphere localization and dose quantification using positron emission tomography/CT following hepatic intraarterial radioembolization with yttrium-90 in patients with advanced hepatocellular carcinoma.

PURPOSE: To characterize the distribution of absorbed radiation dose after glass microsphere radioembolization for hepatocellular carcinoma (HCC) using yttrium-90 ((90)Y) positron emission tomography/computed tomography (PET/CT). MATERIALS AND METHODS: In this retrospective study, 64 (90)Y PET/CT scans performed after treatment were evaluated following (90)Y glass-bead radioembolization in patients with advanced HCC. The intended dose to the target volume ranged from 83-129 Gy. Three-dimensional "dose maps" were created from reconstructed PET images using a voxel-based S-value transformation. Liver parenchyma and liver tumors were contoured on cross-sectional imaging and aligned with the created dose maps. RESULTS: There were 113 tumors examined as part of 64 lobar treatments. The average tumor size was 4.8 cm ± 4.0 with an average tumor dose of 173 Gy ± 109. The average dose to the nontumor parenchyma within the target volume was 93.4 Gy ± 32.6, with on average 50% of the parenchymal voxels receiving > 79 Gy ± 23 and 10% receiving > 173 Gy ± 55. The average and median tumor-to-parenchymal weighted dose ratios were 2.2 and 1.9, respectively. CONCLUSIONS: Using recommended dosimetry and administration techniques for lobar glass microsphere radioembolization, high doses to target tumors as well as background parenchyma were achieved on average with modest preferential uptake within tumors. There was wide variation in measured tumor and parenchymal doses after hepatic radioembolization for HCC, suggesting the need for continued development of patient-specific dosimetry.

The utility of secretin-enhanced MRCP in diagnosing congenital anomalies.

PURPOSE: To assess the additional value of secretin-enhanced MRCP (SMRCP) over conventional MRCP in diagnosing divisum. METHODS: Retrospective HIPAA-compliant and IRB-approved review found 140 patients with SMRCP and ERCP correlation within 6 months of each other. All studies were anonymized and the SMRCP images (SMRCP image set) were separated from 2D and 3D MRCP and axial and coronal T2-weighted images (conventional MRI image set). Each image set on each patient was assigned different and randomized case numbers. Two reviewers (R1 and R2) independently reviewed the image sets for divisum vs. no divisum, complete divisum vs. incomplete divisum, and the certainty of diagnosis (1 = definitely certain, 2 = moderately certain, and 3 = unsure). ERCP findings were taken as gold standard. RESULTS: There was no difference in age and gender between the divisum (n = 97, with 13 incomplete divisum) and no divisum (n = 43) groups. In diagnosing divisum anatomy, the sensitivity was higher for SMRCP compared to conventional MRI for R1 (84.5 vs. 72.2, p = 0.02) but not R2 (89.7 vs. 84.4, p = 0.25). The specificity was higher in SMRCP image set compared to conventional MRI (R1: 88.1 vs. 76.2, p = 0.01; R2: 81.4 vs. 65.1, p < 0.001). The mean area under ROC curve was higher for SMRCP image set (R1: 0.86 vs. 0.74, p = 0.01; R2: 0.87 vs. 0.74, p = 0.01). The certainty of diagnosis was higher in SMRCP image set compared to conventional MRI (p = 0.02 for both reviewers). SMRCP was not found to be superior in distinguishing incomplete from complete divisum. The main reasons for erroneous SMRCP diagnosis were the presence of an ansa loop in the main duct and ductal strictures due to chronic pancreatitis. CONCLUSION: Even though the reviewers had more sequences (axial and coronal) to evaluate in the non-secretin image set, there was some improvement in diagnosing divisum with SMRCP.

Comparison of tracer kinetic models for 68Ga-PSMA-11 PET in intermediate-risk primary prostate cancer patients.

BACKGROUND: 68Ga-PSMA-11 positron emission tomography enables the detection of primary, recurrent, and metastatic prostate cancer. Regional radiopharmaceutical uptake is generally evaluated in static images and quantified as standard uptake values (SUVs) for clinical decision-making. However, analysis of dynamic images characterizing both tracer uptake and pharmacokinetics may offer added insights into the underlying tissue pathophysiology. This study was undertaken to evaluate the suitability of various kinetic models for 68Ga-PSMA-11 PET analysis. Twenty-three lesions in 18 patients were included in a retrospective kinetic evaluation of 55-min dynamic 68Ga-PSMA-11 pre-prostatectomy PET scans from patients with biopsy-demonstrated intermediate- to high-risk prostate cancer. Three kinetic models-a reversible one-tissue compartment model, an irreversible two-tissue compartment model, and a reversible two-tissue compartment model, were evaluated for their goodness of fit to lesion and normal reference prostate time-activity curves. Kinetic parameters obtained through graphical analysis and tracer kinetic modeling techniques were compared for reference prostate tissue and lesion regions of interest. RESULTS: Supported by goodness of fit and information loss criteria, the irreversible two-tissue compartment model optimally fit the time-activity curves. Lesions exhibited significant differences in kinetic rate constants (K1, k2, k3, Ki) and semiquantitative measures (SUV and %ID/kg) when compared with reference prostatic tissue. The two-tissue irreversible tracer kinetic model was consistently appropriate across prostatic zones. CONCLUSIONS: An irreversible tracer kinetic model is appropriate for dynamic analysis of 68Ga-PSMA-11 PET images. Kinetic parameters estimated by Patlak graphical analysis or full compartmental analysis can distinguish tumor from normal prostate tissue.

Use of diffusion-weighted MRI to differentiate chronic pancreatitis from pancreatic cancer.

OBJECTIVE: The purpose of this study was to compare diffusion-weighted MRI (DWI) and conventional (non-DWI) MRI sequences in differentiating mass-forming chronic pancreatitis from pancreatic cancer. MATERIALS AND METHODS: A retrospective cohort study included 36 patients who underwent pancreatic resection for pancreatic cancer (n = 13) and chronic pancreatitis (n = 23) after preoperative MRI with DWI. Two independent reviewers assessed the DW images for signal intensity and apparent diffusion coefficient (ADC) values. Four weeks later, they reviewed the other MR images for size of mass, double-duct sign, pancreatic duct cutoff, and perivascular soft-tissue cuffing. A score for conventional MRI was given with 1 meaning definitely benign and 5 meaning definitely malignant. Univariate and multivariate analyses and receiver operating characteristic (ROC) curve analysis were performed with surgical pathologic examination as the reference standard. RESULTS: The only finding that differentiated the two groups was the presence of a well-defined mass, favoring the diagnosis of cancer (p = 0.02, p < 0.01). There was no significant difference between the two groups in signal intensity on DW images (p = 0.82, p = 0.85) or ADC (p = 0.51, p = 0.76). Double-duct sign, pancreatic duct cutoff, and perivascular soft-tissue cuffing were not useful in differentiating the two groups. The areas under the ROC curve were 0.873 and 0.878 for the conventional MRI scores, compared with 0.602 and 0.552 for ADC measurements (p = 0.02, p = 0.008). CONCLUSION: The addition of DWI to conventional MRI does not facilitate differentiation of pancreatic cancer from chronic pancreatitis.

Usefulness of conventional MRI sequences and diffusion-weighted imaging in differentiating malignant from benign portal vein thrombus in cirrhotic patients.

OBJECTIVE: The objective of our study was to determine the value of diffusion-weighted imaging (DWI) and conventional MRI (non-DWI sequences) in differentiating benign portal vein thrombus (PVT) from malignant PVT in cirrhotic patients. MATERIALS AND METHODS: A retrospective search of the department of radiology's MRI database of examinations performed from October 2006 through December 2010 for "portal vein thrombosis" and "cirrhosis" and "hepatocellular cancer" was performed. Patients who underwent diagnostic DWI and had thrombus shown to be rapidly (< 3 months) increasing in size despite anticoagulation therapy were considered to have malignant PVT (n = 16 cases) and patients with MRI findings showing stability or reduction in the extent of thrombus over a 12-month follow-up were considered to have benign PVT (n = 20 cases). Two blinded and independent reviewers analyzed the DW images and conventional MR images. RESULTS: There was no difference in the distribution of patients by age (p = 0.25) or sex (p = 0.68) between the benign and malignant PVT groups. On multivariate analysis, the only parameter to predict the type of PVT was the size of HCC (p = 0.05); other parameters were excluded from the model. There was substantial overlap in apparent diffusion coefficient (ADC) values and PVT/liver ADC ratios of benign PVT and malignant PVT. The presence of at least two of the three following MRI findings had a sensitivity of 100% and specificity of 90% for the diagnosis of malignant PVT: distance from tumor to PVT of less than 2 cm, HCC size of greater than 5 cm, and arterial enhancement of PVT. CONCLUSION: Signal-intensity characteristics on DWI and measured ADC values do not reliably differentiate benign PVT from malignant PVT. On the other hand, careful assessment of conventional MRI findings may allow this distinction, thus obviating biopsy.

Response criteria in oncologic imaging: review of traditional and new criteria.

There has been a proliferation and divergence of imaging-based tumor-specific response criteria over the past 3 decades whose purpose is to achieve objective assessment of treatment response in oncologic clinical trials. The World Health Organization (WHO) criteria, published in 1981, were the first response criteria and made use of bidimensional measurements of tumors. The Response Evaluation Criteria in Solid Tumors (RECIST) were created in 2000 and revised in 2009. The RECIST criteria made use of unidimensional measurements and addressed several pitfalls and limitations of the original WHO criteria. Both the WHO and RECIST criteria were developed during the era of cytotoxic chemotherapeutic agents and are still widely used. However, treatment strategies changed over the past decade, and the limitations of using tumor size alone in patients undergoing targeted therapy (including arbitrarily determined cutoff values to categorize tumor response and progression, lack of information about changes in tumor attenuation, inability to help distinguish viable tumor from nonviable components, and inconsistency of size measurements) necessitated revision of these criteria. More recent criteria that are used for targeted therapies include the Choi response criteria for gastrointestinal stromal tumor, modified RECIST criteria for hepatocellular carcinoma, and Immune-related Response Criteria for melanoma. The Cheson criteria and Positron Emission Tomography Response Criteria in Solid Tumors make use of positron emission tomography to provide functional information and thereby help determine tumor viability. As newer therapeutic agents and approaches become available, it may be necessary to further modify existing anatomy-based response-assessment methodologies, verify promising functional imaging methods in large prospective trials, and investigate new quantitative imaging technologies.

Comparison of Tracer Kinetic Models for 68Ga-PSMA-11 PET in Intermediate Risk Primary Prostate Cancer Patients.

BACKGROUND: 68Ga-PSMA-11 positron emission tomography enables the detection of primary, recurrent, and metastatic prostate cancer. Regional radiopharmaceutical uptake is generally evaluated in static images and quantified as standard uptake values (SUV) for clinical decision-making. However, analysis of dynamic images characterizing both tracer uptake and pharmacokinetics may offer added insights into the underlying tissue pathophysiology. This study was undertaken to evaluate the suitability of various kinetic models for 68Ga-PSMA-11 PET analysis. Twenty-three lesions in 18 patients were included in a retrospective kinetic evaluation of 55-minute dynamic 68Ga-PSMA-11 pre-prostatectomy PET scans from patients with biopsy-demonstrated intermediate to high-risk prostate cancer. A reversible one-tissue compartment model, irreversible two-tissue compartment model, and a reversible two-tissue compartment model were evaluated for their goodness-of-fit to lesion and normal reference prostate time-activity curves. Kinetic parameters obtained through graphical analysis and tracer kinetic modeling techniques were compared for reference prostate tissue and lesion regions of interest. RESULTS: Supported by goodness-of-fit and information loss criteria, the irreversible two-tissue compartment model was selected as optimally fitting the time-activity curves. Lesions exhibited significant differences in kinetic rate constants (K1, k2, k3, Ki) and semiquantitative measures (SUV) when compared with reference prostatic tissue. The two-tissue irreversible tracer kinetic model was consistently appropriate across prostatic zones. CONCLUSIONS: An irreversible tracer kinetic model is appropriate for dynamic analysis of 68Ga-PSMA-11 PET images. Kinetic parameters estimated by Patlak graphical analysis or full compartmental analysis can distinguish tumor from normal prostate tissue.

Assessing extra-prostatic extension for surgical guidance in prostate cancer: Comparing two PSMA-PET tracers with the standard-of-care.

BACKGROUND: Incontinence and impotence occur following radical prostatectomy due to injury to nerves and sphincter muscle. Preserving nerves and muscle adjacent to prostate cancer risks positive surgical margins. Advanced imaging with MRI has improved cancer localization but limitations exist. OBJECTIVE: To measure the accuracy for assessing extra-prostatic extension at nerve bundles for 2 PSMA-PET tracers and to compare the PET accuracy to standard-of-care predictors including MRI and biopsy results. MATERIALS AND METHODS: We studied men with PSMA-targeted PET imaging, performed prior to prostatectomy in men largely with intermediate to high-risk prostate cancer, and retrospectively evaluated for assessment of extra-prostatic extension with whole-mount analysis as reference standard. Two different PSMA-PET tracers were included: 68Ga-PSMA-11 and 68Ga-P16-093. Blinded reviews of the PET and MRI scans were performed to assess extra-prostatic extension (EPE). Sensitivity and specificity for extra-prostatic extension were compared using McNemar's Chi2. RESULTS: Pre-operative PSMA-PET imaging was available for 71 patients with either 68Ga-P16-093 (n = 25) or 68Ga-PSMA-11 (n = 46). There were 24 (34%) with pT3a (EPE) and 16 (23%) with pT3b (SVI). EPE Sensitivity (87% vs. 92%), Specificity (77% vs. 76%), and ROC area (0.82 vs. 0.84) were similar between P16-093 and PSMA-11, respectively (P = 0.87). MRI (available in only 45) found high specificity (83%) but low sensitivity (60%) for EPE when using a published grading system. MRI sensitivity was significantly lower than the PSMA-PET (60% vs. 90%, P = 0.02), but similar to PET when using a >5 mm capsular contact (76% vs. 90%, P = 0.38). A treatment change to "nerve sparing" was recommended in 21 of 71 (30%) patients based on PSMA-PET imaging. CONCLUSIONS: Presurgical PSMA-PET appeared useful as a tool for surgical planning, changing treatment plans in men with ≥4+3 or multi-core 3+4 prostate cancer resulting in preservation of nerve-bundles.

Non-alcoholic fatty liver disease is not associated with impairment in health-related quality of life in virally suppressed persons with human immune deficiency virus.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in persons with HIV (PWH) (HIV-NAFLD). It is unknown if HIV-NAFLD is associated with impairment in health-related quality of life (HRQOL). We examined HRQOL in PWH with and without NAFLD, compared HRQOL in HIV- versus primary NAFLD, and determined factors associated with HRQOL in these groups. Prospectively enrolled 200 PWH and 474 participants with primary NAFLD completed the Rand SF-36 assessment which measures 8 domains of HRQOL. Individual domain scores were used to create composite physical and mental component summary scores. Univariate and multivariate analyses determined variables associated with HRQOL in PWH and in HIV- and primary NAFLD. In PWH, 48% had HIV-NAFLD, 10.2% had clinically significant fibrosis, 99.5% were on antiretroviral therapy, and 96.5% had HIV RNA <200 copies/ml. There was no difference in HRQOL in PWH with or without NAFLD. Diabetes, non-Hispanic ethnicity, and nadir CD4 counts were independently associated with impaired HRQOL in PWH. In HIV-NAFLD, HRQOL did not differ between participants with or without clinically significant fibrosis. Participants with HIV-NAFLD compared to those with primary NAFLD were less frequently cisgender females, White, more frequently Hispanic, had lower BMI and lower frequency of obesity and diabetes. HRQOL of individuals with HIV-NAFLD was not significantly different from those with primary NAFLD. In conclusion, in virally suppressed PWH, HRQOL is not different between participants with or without HIV-NAFLD. HRQOL is not different between HIV-NAFLD and primary NAFLD.