Unconventional Strategies for Solid Organ Transplantation and Special Transplantation Scenarios.

Solid organ transplantation is the only long-term therapeutic option for patients with end-organ failure but cadaveric and living donor transplant pools are unable to meet the demand for organ transplantation. Newer techniques, innovative strategies and altruistic donors can help bridge this wide gap between the number of organ donors and recipients. Domino liver transplantation, paired organ donation, and ABO incompatible transplants are some of the ways to ensure increased transplant organ availability. Split liver transplantation and ex vivo liver resection and auto transplantation are considered surgically challenging but are being done at tertiary transplant centers.

Comprehensive Review of Serous Tumors of Tubo-Ovarian Origin: Clinical Behavior, Pathological Correlation, Current Molecular Updates, and Imaging Manifestations.

Ovarian cancer is the eighth most common women's cancer worldwide, with the highest mortality rate of any gynecologic malignancy. On a global scale, the World Health Organization (WHO) reports that ovarian cancer has approximately 225,000 new cases every year with approximately 145,000 deaths. According to the National Institute of Health, Surveillance Epidemiology and End Results program (SEER) database, 5-year survival for women with ovarian cancer in the United States is 49.1%. High-grade serous ovarian carcinoma typically presents at an advanced stage and accounts for the majority of these cancer deaths. Given their prevalence and the lack of a reliable method for screening, early and reliable diagnosis of serous cancers is of paramount importance. Early differentiation of borderline, low and high-grade lesions can assist in surgical planning and support challenging intraoperative diagnoses. The objective of this article is to provide a review of the pathogenesis, diagnosis, and treatment of serous ovarian tumors, with a specific focus on the imaging characteristics that help to preoperatively differentiate borderline, low-grade, and high-grade serous ovarian lesions.

Pancreatic Malakoplakia: A Rare Pathology Associated With Acute Pancreatitis.

Malakoplakia is a rare granulomatous tumor-like inflammatory condition, most frequently involving the genitourinary system and occurring in immunosuppressed patients. The gastrointestinal tract is the second most common site, where it is usually seen involving the colon. We report a case of malakoplakia presenting as a pancreatic mass. Imaging showed soft tissue along the pancreatic tail/greater curvature concerning for infiltrating tumor, but endoscopic ultrasound with biopsy showed malakoplakia. Our case discusses malakoplakia at an uncommon site, which was appropriately treated with antibiotics.

MRI as First Line Imaging for Suspected Acute Appendicitis during Pregnancy: Diagnostic Accuracy and level of Inter-Radiologist Agreement.

OBJECTIVE: Evaluation of acute appendicitis (AA) in pregnancy is supported with diagnostic imaging. Typically, ultrasound (US) is performed first, and then often followed by magnetic resonance imaging (MRI) due to continued diagnostic uncertainty. The purpose of our study was to evaluate the sensitivity, specificity, and accuracy of US as compared to MRI and to evaluate the inter-radiologist agreement amongst body Radiologists with varying levels of expertise. MATERIALS AND METHODS: We performed a retrospective study of 364 consecutive pregnant patients with clinical suspicion of AA at a single center over a 6-year period. Sensitivity, Specificity, accuracy, positive and negative predictive values were calculated for US and MRI. Inter Radiologist agreement was determined using Cohen's Kappa analysis between original interpreting Radiologist and retrospective review by expert Radiologist. RESULTS: Thirty-one of 364 patients (8.5%) underwent appendectomy based on preoperative diagnosis, with confirmation of acute appendicitis (AA) by pathology in 19. US was able to visualize the appendix in only 6 (1.65%), 5 of whom had appendicitis. 141 patients underwent MRI, and correctly diagnosed appendicitis in 9. No patient with a negative MRI diagnosis had AA. The sensitivity, and negative predictive value for diagnosing AA with MRI was 100%. The MRI inter-reader agreement for appendix visualization and overall accuracy were 87.9 and 98% with Cohen Kappa of 0.7 and 0.56 respectively. CONCLUSIONS: Our data suggests that MRI should be considered the first line imaging modality in pregnant patients suspected of having AA. Body Radiologists with varied levels of experience in MRI readouts had substantial agreement.

Diagnostic Value of FDG PET/MRI in Females With Pelvic Malignancy-A Systematic Review of the Literature.

Hybrid imaging with F-18 fludeoxyglucose positron emission tomography/magnetic resonance imaging (FDG PET/MRI) has increasing clinical applications supplementing conventional ultrasound, CT, and MRI imaging as well as hybrid PET/CT imaging in assessing cervical, endometrial, and ovarian cancer. This article summarizes the existing literature and discusses the emerging role of hybrid PET/MRI in gynecologic malignancies. Thus, far, the published literature on the applications of FDG PET/MRI shows that it can have a significant impact on patient management by improving the staging of the cancers compared with PET/CT, influencing clinical decision and treatment strategy. For disease restaging, current literature indicates that PET/MRI performs equivalently to PET/CT. There appears to be a mild-moderate inverse correlation between standard-uptake-value (SUV) and apparent-diffusion-coefficient (ADC) values, which could be used to predict tumor grading and risk stratification. It remains to be seen as to whether multi-parametric PET/MRI imaging could prove valuable for prognostication and outcome. PET/MRI provides the opportunity for reduced radiation exposure, which is particularly relevant for a young female in need of multiple scans for treatment monitoring and follow-up. Fast acquisition protocols and optimized methods for attenuation correction are still evolving. Major limitations of PET/MRI remains such as suboptimal detection of small pulmonary nodules and lack of utility for radiation treatment planning, which pose an impediment in making PET/MRI a viable one-stop-shop imaging option to compete with PET/CT.

18F-FDG PET/MRI Primary Staging of Cervical Cancer: A Pilot Study with PET/CT Comparison.

We report our PET/MRI experience from a pilot study that compared the diagnostic performance of 18F-FDG PET/MRI versus PET/CT in staging of cervical cancer. Methods: Six adults with newly diagnosed cervical cancer underwent a single 18F-FDG injection with a dual-imaging protocol: standard-of-care PET/CT followed by research PET/MRI. The diagnostic interpretation and SUVmax for the 2 modalities were compared. Results: Both modalities detected all primary tumors (median size, 3.9 cm) and all 4 metastases present in 2 of the 6 patients (median size, 0.9 cm). PET/MRI provided greater diagnostic confidence than PET/CT and upstaged the disease in 4 patients. On the basis of the imaging findings alone, the additional information from PET/MRI would have led to a change in clinical management in 3 of 6 patients. The primary lesion showed a median SUV of 12.8 on PET/CT and 18.2 on PET/MRI (P = 0.03). SUVs, however, correlated strongly between the 2 modalities (ρ = 0.96, P < 0.001). Conclusion: Our pilot study supports the notion that PET/MRI has the potential to impact clinical decisions and treatment strategies in women with cervical cancer. Further studies are, however, warranted to define the value that PET/MRI adds to PET/CT.

Enhancement pattern of hepatocellular adenoma (HCA) on MR imaging performed with Gd-EOB-DTPA versus other Gd-based contrast agents (GBCAs): An intraindividual comparison.

PURPOSE: To conduct an intraindividual comparison of the enhancement pattern of hepatocellular adenoma (HCA) on dynamic MRI study obtained following the injection of Gadoxetic acid (Gd-EOB-DTPA) and other gadolinium-based contrast agents (GBCAs). METHOD: This is a retrospective, Institutional Review Board-approved study conducted in a single institution. A search of medical records between 2008 and 2017 revealed 17 patients (all females) with at least one pathologically-proven HCA who underwent liver MRI with Gd-EOB-DTPA and another GBCA within 1 year. Enhancement of each lesion on hepatic arterial (HAP), portal venous (PVP), 2 min and 4-5 minutes phases was subjectively evaluated by two abdominal radiologists. Lesions were categorized as hyper-, iso- or hypointense compared to the surrounding liver parenchyma. The presence of a peripheral pseudocapsule was also recorded. The differences in lesion enhancement were assessed using the McNemar Test. A p-value <0.05 was considered statistically significant. RESULTS: The final population included 35 HCAs (83% inflammatory subtype). There was no significant difference in lesion size (P = 0.708) and enhancement on HAP (P = 0.625) or PVP (P = 0.125). HCAs showed more frequently hypointensity on 2 min (13/35 vs. 1/35, P < 0.001) and 4-5 minutes (P < 0.001) images obtained after injection of Gd-EOB-DTPA compared to those obtained after other GBCAs. A pseudocapsule was more frequently noted after administration of Gd-EOB-DTPA (13/35 vs 1/35, P = 0.002). CONCLUSIONS: Enhancement pattern of HCA differs significantly after the injection of Gd-EOB-DTPA compared to other GBCAs. Lesion hypointensity on 2 min and 4-5 minutes images is more frequent when using Gd-EOB-DTPA.

Magnetic resonance imaging response in patients treated with definitive radiation therapy for medically inoperable endometrial cancer-Does it predict treatment response?

PURPOSE: Many patients with endometrial cancer cannot undergo surgery and instead receive definitive radiation therapy (RT). We investigate the correlation between MRI response to RT and clinical outcomes. METHODS AND MATERIALS: Women with inoperable, clinical Stage I endometrial cancer were treated with definitive brachytherapy (BT) with/without pelvic RT (PRT). Patients underwent MRI with functional diffusion-weighted imaging before and after RT. A radiologist retrospectively classified cases as complete, partial, or indeterminate response (CR, PR, or IR, respectively) vs. disease progression. Local control was clinicopathologically defined. RESULTS: From 2007 to 2017, 50 women underwent definitive RT. Thirty-five (70%) received BT alone (median dose 37.5 Gy). For combined therapy, the median PRT and BT doses were 45 and 25 Gy, respectively. Median gross tumor volume and high-risk clinical target volume were 7.1 cc and 90.0 cc, respectively. Median followup among living patients was 20 months. All patients underwent post-RT MRI with T1/T2 sequencing at a median of 3.2 months after RT; 40 patients (80%) underwent functional diffusion-weighted imaging sequences. On initial post-RT MRI, CR was documented in 42 patients (84%), IR in 1 patient (2%), and PR in seven patients (14%). At median followup of 16.3 months, no CR patients had uterine failure. Among eight patients with initial PR/IR, all were found to be clinicopathologically no evidence of disease at the uterus on further evaluation. CONCLUSIONS: Definitive RT with BT or BT + PRT is associated with high response rates on MRI. Overall, initial CR predicted for excellent outcome with no infield failure.

Imaging and Pathologic findings of Hepatic Small Vessel Hemangioma.

Hepatic small vessel hemangioma represents a distinct yet very rare pathologic entity of the liver. The entity has also been in the past referred to as adult capillary hemangioma of the liver and congenital noninvoluting hemangioma. Imaging findings are not definitive and biopsy or resection is ultimately necessary. Pathologically these represent vasoformative abnormalities with infiltrative margins that can potentially mimic hepatic angiosarcoma. Immunohistochemistry can help differentiate hepatic small vessel hemangioma from angiosarcoma. Given the infiltrative growth pattern and unknown outcomes, resection and or close follow up has been recommended. Recently the term hepatic small vessel neoplasm has been coined in view of the unknown outcomes and some concerning findings on molecular analysis. We report 2 cases of this unusual entity and describe its imaging, gross pathologic, histopathologic, and immunohistochemical features.

Value of Texture Analysis on Gadoxetic Acid-Enhanced MRI for Differentiating Hepatocellular Adenoma From Focal Nodular Hyperplasia.

OBJECTIVE: The objective of our study was to assess the diagnostic performance of texture analysis (TA) on gadoxetic acid-enhanced MR images for differentiation of hepatocellular adenoma (HCA) from focal nodular hyperplasia (FNH). MATERIALS AND METHODS: This study included 40 patients (39 women and one man) with 51 HCAs and 28 patients (27 women and one man) with 32 FNH lesions. All lesions were histologically proven with preoperative MRI performed with gadoxetic acid. Two readers reviewed all the imaging sequences to assess the qualitative MRI characteristics. The T2-weighted fast spin-echo, hepatic arterial phase (HAP), and hepatobiliary phase (HBP) sequences were used for TA. Textural features were extracted using commercially available software (TexRAD). The differences in distributions of TA parameters of FNHs and HCAs were assessed using the Mann-Whitney U test. Area under the ROC curve (AUROC) values were calculated for statistically significant features. A logistic regression analysis was conducted to explore the added value of TA. A p value < 0.002 was considered statistically significant after Bonferroni correction for multiple comparisons. RESULTS: Multiple TA parameters showed a statistically different distribution in HCA and FNH including skewness on T2-weighted imaging, skewness on HAP imaging, skewness on HBP imaging, and entropy on HBP imaging (p < 0.001). Skewness on HBP imaging showed the largest AUROC (0.869; 95% CI, 0.777-0.933). A skewness value on HBP imaging of greater than -0.06 had a sensitivity of 72.5% and a specificity of 90.6% for the diagnosis of HCA. Six of 51 (11.8%) HCAs lacked hypointensity on HBP imaging. A binary logistic regression analysis including hypointensity on HBP imaging and the statistically significant TA parameters yielded an AUROC of 0.979 for the diagnosis of HCA and correctly predicted 96.4% of the lesions. CONCLUSION: TA may be of added value for the diagnosis of atypical HCA presenting without hypointensity on HBP imaging.

Use of Functional Magnetic Resonance Imaging in Cervical Cancer Patients With Incomplete Response on Positron Emission Tomography/Computed Tomography After Image-Based High-Dose-Rate Brachytherapy.

PURPOSE: To investigate the correlation between positron emission tomography/computed tomography (PET/CT) response and outcome in the era of magnetic resonance imaging (MRI)-based planning and to assess whether the addition of diffusion-weighted MRI (DW-MRI) could more accurately classify treatment response and prognosis. METHODS AND MATERIALS: A retrospective chart review identified 244 consecutive patients with International Federation of Gynecology and Obstetrics stage IB1-IVA cervical cancer treated with concurrent chemoradiation, including high-dose-rate image-based brachytherapy, between 2007 and 2016. Image-based brachytherapy was delivered with 5 intracavitary/interstitial fractions, each 5 to 6 Gy per fraction. RESULTS: An complete response on posttreatment PET/CT (PET-CR) was discovered in 50 of 244 patients (20%) at a median interval of 3.3 months (range, 2.1-7.7 months) after treatment. After a median follow-up of 27 months, 2-year overall survival was 83% in all patients. Metabolic response significantly impacted 2-year overall survival (94% complete response on posttreatment PET/ CT vs 62.4% PET-IR, P < .001). Of those with a PET-IR, 16 of 50 patients (32%) suffered a local recurrence. A total of 27 of 50 patients with a PET-IR underwent DW-MRI; 11 of 27 posttreatment DW-MRI scans (40%) were interpreted as positive by central review (median apparent diffusion coefficient of 0.973 × 10-3 mm2/s). Of the DW-MRI-positive patients, 9 of 11 (81.8%) suffered a histologically confirmed local recurrence, and 2 of 11 patients are without evidence of disease. Additionally, 16 of 27 DW-MRI studies were interpreted as negative, and 2 of 16 (12.5%) of these patients suffered a local recurrence. Diffusion-weighted MRI findings significantly impacted 2-year overall survival (83% negative DW-MRI vs 36% positive DW-MRI, P = .049). CONCLUSION: Incomplete PET/CT response was documented in 20% of patients after image-based brachytherapy for locally advanced cervical cancer. Integration of DW-MRI helped accurately identify patients at risk for persistent disease and worse long-term outcome. The value of DW-MRI requires further validation in a large prospective dataset as this modality may allow earlier evaluation and salvage treatment in those with PET-IR.

CT Intensity Distribution Curve (Histogram) Analysis of Patients Undergoing Antiangiogenic Therapy for Metastatic Renal Cell Carcinoma.

OBJECTIVE: The purpose of this study was to evaluate the median versus mean attenuation obtained from histograms in the response assessment of renal cell carcinoma (RCC) target lesions in patients treated with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors. MATERIALS AND METHODS: Imaging findings of 19 patients with RCC and treated with a VEGFR tyrosine kinase inhibitor that included a baseline study and at least two follow-up studies were retrospectively analyzed. Histograms of target lesions were created from ROI measurements, and mean and median lesion attenuation were obtained. Shift of mean and median was used to classify response of lesions between baseline CT and the first follow-up examination according to the Choi criteria; morphology, attenuation, size, and structure (MASS) criteria; and the Response Evaluation Criteria in Solid Tumors (RECIST). RECIST classification of the last follow-up CT examination was considered the reference standard. RESULTS: Among the 19 patients (six women, 13 men; mean age, 60 ± 8 [SD] years; body mass index, 24.5 ± 4.6 kg/m2), three (16%) had evidence of disease progression; nine (47%), partial response; and seven (37%), stable disease. Temporal change in the shape of the histograms from or to gaussian occurred in 11 of the 19 (58%) lesions, which accounted for a significant difference between mean (64.3 ± 38.5 HU) and median (71.0 ± 36.5 HU) lesion attenuation (p < 0.001). According to the shift of median for outcome analysis, the number of properly classified lesions increased from 12 of 19 (63%) to 13 of 19 (68%) for the Choi criteria and from 14 of 19 (74%) to 15 of 19 (79%) for the MASS criteria. CONCLUSION: Mean and median attenuation of RCC target lesions differed significantly. Use of shift of median rather than shift of mean increased the number of accurate classifications of lesions at the first follow-up CT examination.

A novel mutation in the succinate dehydrogenase subunit D gene in siblings with the hereditary paraganglioma-pheochromocytoma syndrome.

Germline mutations in the succinate dehydrogenase complex subunit D gene are now known to be associated with hereditary paraganglioma-pheochromocytoma syndromes. Since the initial succinate dehydrogenase complex subunit D gene mutation was identified about a decade ago, more than 131 unique variants have been reported. We report the case of two siblings presenting with multiple paragangliomas and pheochromocytomas; they were both found to carry a mutation in the succinate dehydrogenase complex subunit D gene involving a substitution of thymine to guanine at nucleotide 236 in exon 3. This particular mutation of the succinate dehydrogenase complex subunit D gene has only been reported in one previous patient in Japan; this is, therefore, the first report of this pathogenic mutation in siblings and the first report of this mutation in North America. With continued screening of more individuals, we will be able to create a robust mutation database that can help us understand disease patterns associated with particular variants and may be a starting point in the development of new therapies for familial paraganglioma syndromes.

Improvement in the detection of locoregional recurrence in head and neck malignancies: F-18 fluorodeoxyglucose-positron emission tomography/computed tomography compared to high-resolution contrast-enhanced computed tomography and endoscopic examination.

OBJECTIVES/HYPOTHESIS: To compare the diagnostic efficacy of positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG-PET)/computed tomography (CT) to that of contrast-enhanced high-resolution CT (HRCT) and assess the value of a combinatorial approach in detection of recurrent squamous cell cancer of the head and neck (HNC) and to assess the efficacy of FDG-PET/CT with and without HRCT in comparison to standard-of-care follow-up--physical examination (PE) and endoscopy (E)--in determination of locally recurrent HNC. STUDY DESIGN: Retrospective study. METHODS: A total of 103 patients with HNC underwent FDG-PET/CT and neck HRCT. There were two groups of patients: Group A had an FDG-PET study acquired with low-dose CT, and group B had an FDG-PET study acquired with HRCT. The PET data obtained with or without HRCT were compared on a lesion and patient basis with the results of the PE/E. RESULTS: On a lesion basis, both groups combined had higher sensitivity and negative predictive value (NPV) than the HRCT. Specificity and positive predictive value (PPV) for group B were higher than for group A. On a patient basis, both groups combined had a higher sensitivity and NPV than PE/E, respectively, although specificity of PE/E was higher than that of either group. PET data obtained with either protocol directly influenced treatment. CONCLUSIONS: HRCT increases the specificity and PPV of PET/CT when acquired simultaneously with PET. FDG-PET/CT acquired with either LDCT or HRCT has higher accuracy than HRCT alone and increases the sensitivity and NPV of PE/E.

The optimized evaluation of diabetic foot infection by dual isotope SPECT/CT imaging protocol.

Sequential Tc-99m hydroxymethylene-diphosphonate (HDP) 3-phase bone (BS) and In-111 leukocyte scanning (WBCS) have been frequently used to evaluate the diabetic foot, as nonosteomyelitis BS uptake is repeatedly observed and osteomyelitis (OM) in WBCS is often uncertain without BS correlation. Additionally, both modalities are limited in lesion localization because of low resolution and lack of anatomic details. We investigated a method that combined BS/WBCS, and if needed, WBCS/bone marrow scanning (BMS) using SPECT/CT to accurately diagnose/localize infection in a practical protocol. Blood flow/pool images were obtained followed by WBC reinjection and next day dual isotope (DI) BS/WBCS planar and SPECT/CT. BMS/WBCS SPECT/CT (step 2 DI) was obtained on the following day when images were suspicious for mid/hindfoot OM. Diagnosis accuracy and confidence were judged for the various imaging combinations. Diagnosis was classified as OM, soft tissue infection (STI), both OM/STI, and other/no bony pathology by microbiology/pathology or follow-up. Distinction between various diagnostic categories and overall OM diagnostic accuracy in 213 patients were higher for DI than WBCS or BS alone, and for DI SPECT/CT than DI planar or SPECT only. Diagnostic confidence/lesion site was significantly higher for DI SPECT/CT than other comparative imaging methods. In a group of 97 patients with confirmed microbiologic/pathologic diagnosis, similar results were attained. Step 2 DI SPECT/CT performed in 67 patients further improved diagnostic accuracy/confidence. DI SPECT/CT is a highly accurate modality that considerably improves detection and discrimination of STI and OM while providing precise anatomic localization in the diabetic foot. This combined imaging technique promises to beneficially impact diabetic patient care.

Correlation of positron emission tomography standard uptake value and pathologic specimen size in cancer of the head and neck.

PURPOSE: To correlate positron emission tomography (PET) standard uptake value (SUV) with pathologic specimen size in patients with head-and-neck cancers. METHODS AND MATERIALS: Eighteen patients with Stage II-IVB head-and-neck cancer with 27 tumors who underwent PET and computed tomography (CT) imaging of the head and neck followed by surgical resection were selected for this study. Various SUV thresholds were examined, including the software default (SUV(def)), narrowing the window by 1 standard deviation (SD) of the maximum (SUV-1SD), and SUV cutoff values of 2.5 or greater (SUV2.5) and 40% or greater maximum (SUV40). Volumetric pathologic data were available for 12 patients. Tumor volumes based on pathologic examination (gold standard), CT, SUV(def), SUV-1SD, SUV2.5, and SUV40 were analyzed. RESULTS: PET identified five tumors not seen on CT. The sensitivity of PET for identifying primary tumors was 94% (17 of 18). The Sensitivity of PET for staging the neck was 90% (9 of 10), whereas the specificity was 78% (7 of 9). The SUV2.5 method was most likely to overestimate tumor volume, whereas SUV(def) and SUV-1SD were most likely to underestimate tumor volume. CONCLUSIONS: The PET scan provides more accurate staging of primary tumors and nodal metastases for patients with advanced head-and-neck cancer than CT alone. Compared with the gold standard, significant variability exists in volumes obtained by using various SUV thresholds. A combination of clinical, CT, and PET data should continue to be used for optimal treatment planning. The SUV40 method appears to offer the best compromise between accuracy and reducing the risk of underestimating tumor extent.