Metabolic Heterogeneity in Human Lung Tumors.

Non-small cell lung cancer (NSCLC) is heterogeneous in the genetic and environmental parameters that influence cell metabolism in culture. Here, we assessed the impact of these factors on human NSCLC metabolism in vivo using intraoperative (13)C-glucose infusions in nine NSCLC patients to compare metabolism between tumors and benign lung. While enhanced glycolysis and glucose oxidation were common among these tumors, we observed evidence for oxidation of multiple nutrients in each of them, including lactate as a potential carbon source. Moreover, metabolically heterogeneous regions were identified within and between tumors, and surprisingly, our data suggested potential contributions of non-glucose nutrients in well-perfused tumor areas. Our findings not only demonstrate the heterogeneity in tumor metabolism in vivo but also highlight the strong influence of the microenvironment on this feature.

Real-time influence of intracellular acidification and Na+ /H+ exchanger inhibition on in-cell pyruvate metabolism in the perfused mouse heart: A 31 P-NMR and hyperpolarized 13 C-NMR study.

Disruption of acid-base balance is linked to various diseases and conditions. In the heart, intracellular acidification is associated with heart failure, maladaptive cardiac hypertrophy, and myocardial ischemia. Previously, we have reported that the ratio of the in-cell lactate dehydrogenase (LDH) to pyruvate dehydrogenase (PDH) activities is correlated with cardiac pH. To further characterize the basis for this correlation, these in-cell activities were investigated under induced intracellular acidification without and with Na+ /H+ exchanger (NHE1) inhibition by zoniporide. Male mouse hearts (n = 30) were isolated and perfused retrogradely. Intracellular acidification was performed in two ways: (1) with the NH4 Cl prepulse methodology; and (2) by combining the NH4 Cl prepulse with zoniporide. 31 P NMR spectroscopy was used to determine the intracellular cardiac pH and to quantify the adenosine triphosphate and phosphocreatine content. Hyperpolarized [1-13 C]pyruvate was obtained using dissolution dynamic nuclear polarization. 13 C NMR spectroscopy was used to monitor hyperpolarized [1-13 C]pyruvate metabolism and determine enzyme activities in real time at a temporal resolution of a few seconds using the product-selective saturating excitation approach. The intracellular acidification induced by the NH4 Cl prepulse led to reduced LDH and PDH activities (-16% and -39%, respectively). This finding is in line with previous evidence of reduced myocardial contraction and therefore reduced metabolic activity upon intracellular acidification. Concomitantly, the LDH/PDH activity ratio increased with the reduction in pH, as previously reported. Combining the NH4 Cl prepulse with zoniporide led to a greater reduction in LDH activity (-29%) and to increased PDH activity (+40%). These changes resulted in a surprising decrease in the LDH/PDH ratio, as opposed to previous predictions. Zoniporide alone (without intracellular acidification) did not change these enzyme activities. A possible explanation for the enzymatic changes observed during the combination of the NH4 Cl prepulse and NHE1 inhibition may be related to mitochondrial NHE1 inhibition, which likely negates the mitochondrial matrix acidification. This effect, combined with the increased acidity in the cytosol, would result in an enhanced H+ gradient across the mitochondrial membrane and a temporarily higher pyruvate transport into the mitochondria, thereby increasing the PDH activity at the expense of the cytosolic LDH activity. These findings demonstrate the complexity of in-cell cardiac metabolism and its dependence on intracellular acidification. This study demonstrates the capabilities and limitations of hyperpolarized [1-13 C]pyruvate in the characterization of intracellular acidification as regards cardiac pathologies.

Existing Scores Fail to Predict Bowel Ischemia in Patients With Adhesive Small Bowel Obstruction.

INTRODUCTION: Early recognition of bowel ischemia is critical in patients suffering from acute adhesive small bowel obstruction (ASBO). Recent studies attempted to propose a score combining clinical and radiological factors to predict the risk of bowel ischemia in patients with ASBO. This study aimed to compare and validate the existing clinical scores with a cohort of surgical patients. METHODS: We conducted a retrospective study including all ASBO cases admitted to our institution between January 1, 2005 and December 31, 2019. Based on three existing clinical scores, we calculated the risk of bowel ischemia for each patient. We then divided the cohort into groups based on the risk for bowel ischemia. For each risk-based category, the proportion of patients who underwent surgical resection and were found to have evidence of ischemic bowel was calculated. RESULTS: A total of 160 patients presenting with 217 episodes of acute ASBO were included. One hundred seventy-one (78.8%) cases were managed nonoperatively while 46 cases (21.2%) required surgery. Sixteen patients (7.3%) were eventually found to have ischemic bowel while 13 required small bowel resection (5.9%). All three clinical scores showed correlation between the calculated risk of ischemia and the intraoperative finding of ischemia. However, all three scores overestimated ischemia rates in the high-risk groups, yielding a PPV of 8.3%-28.5% and a NPV of 93.3%-94.7%. CONCLUSIONS: Current clinical scores for predicting bowel ischemia in patients with ASBO are of high value in ruling out ischemia, yet are of extremely low sensitivity, warranting an overly aggressive and unnecessary surgical approach.

Effect of Magnetic Resonance Imaging on Acute Surgical Treatment of Pregnant Patients: A Single Institution Study.

BACKGROUND: Abdominal pathology in pregnant patients is a frequent challenge for emergency department physicians. Ultrasound is the imaging modality of choice but is inconclusive in approximately one-third of cases. Magnetic resonance imaging (MRI) is becoming increasingly available, even in acute settings. Multiple studies have defined the sensitivity and specificity of MRI in this population. OBJECTIVES: To evaluate the use of MRI findings in pregnant patients presenting with acute abdominal complaints to the emergency department. METHODS: This retrospective cohort study was conducted at a single institution. Data were collected on pregnant patients who underwent an MRI for acute abdominal complaints between 2010 and 2019 at a university center. Patient demographics, diagnosis at admission, ultrasound and MRI findings, and discharge diagnosis were recorded and evaluated. RESULTS: In total, 203 pregnant patients underwent an MRI for acute abdominal complaints during the study period. MRI was found without pathology in 138 cases (68%). In 65 cases (32%), the MRI showed findings that could explain the patient's clinical presentation. Patients presenting with long-standing abdominal pain (> 24 hours), fever, leukocytosis, or elevated C-reactive protein values were at a significantly increased risk of having an acute pathology. In 46 patients (22.6%), MRI findings changed the primary diagnosis and management while in 45 patients (22.1%) MRI findings improved characterization of the suspected pathology. CONCLUSIONS: MRI is helpful when clinical and sonographic findings are inconclusive, leading to changes in patient management in more than one-fifth of patients.

Accumulation of 3-aminopropylphosphonate in the ex vivo brain observed by phosphorus-31 nuclear magnetic resonance.

3-aminopropylphosphonate (3-APP) is known for its use as an exogenous indicator of extracellular volume and pH in phosphorus-31 nuclear magnetic resonance (31 P NMR) studies. We used 3-APP for estimating the extracellular volume in NMR studies of several ex vivo preparations including retrograde perfused mouse heart (n = 4), mouse liver slices (n = 2), xenograft breast cancer tumors (n = 7, MCF7), and rat brain slices (n = 4). In the former three preparations, the 3-APP signal was stable in lineshape and intensity for hours and the chemical shift of the signal in the presence of the biological sample was the same as in the perfusion medium without the biological sample. However, in studies of brain slices, the 3-APP signal appeared split into two, with an upfield component (0.7 ± 0.1 ppm to the left) increasing with time and showing a wider linewidth (66.7 ± 12.6 vs. 39.1 ± 7.6 Hz, the latter is of the perfusion medium signal). This finding suggests that 3-APP inadvertently accumulated in brain slices, most likely as a membrane bound form. This observation limits the use of 3-APP as an inert biochemical indicator in brain preparations and should be taken into account when using 3-APP in vivo.

Characterization and Evaluation of Injectable Biodegradable Polymer Multimodality Radiologic Markers in an In Vivo Murine Model.

Biodegradable polymer clips as multidimensional soft tissue biopsy markers were developed with better biocompatibility and imaging features. Unlike the commercially available metallic biopsy markers, the developed polymer clips are temporary implants with similar efficacies as metal markers in imaging and detection and get absorbed within the body with time. Herein, we evaluate the degradation rate of three resorbable polymer-based marker compounds in an in vivo murine model. Three polymers, abbreviated as Polymer A (PLGA poly(lactic-co-glycolic acid)50:50), Polymer B (PLGA (poly(lactic-co-glycolic acid)) 75:25), and Polymer C (polycaprolactone (PCL)), mixed with 20% lipiodol and 0.2% iron oxide and a control polymer were implanted into nine mice, followed by CT and MRI imaging. Images were evaluated for conspicuity. Specimens were examined for tissue analysis of iodine and iron contents. Significant differences in polymer resorption and visualization on CT were noted, particularly at 8 weeks (p < 0.027). Polymers A, B, and C were visible by CT at 4, 6, and 8 weeks, respectively. All marker locations were detected on MRI (T1 and SWI) after 24 weeks, with tattooing of the surrounding soft tissue by iron deposits. CT and MR visible polymer markers can be constructed to possess variable resorption, with stability ranging between 4 and 14 weeks post placement, making this approach suitable for distinct clinical scenarios with varying time points.

Ultrasonographic features can predict outcome of conservative management of acute appendicitis in children.

PURPOSE: To determine whether specific ultrasonographic features can predict failure of conservative treatment of acute appendicitis. METHODS: A 2-year retrospective study was conducted on children admitted with acute appendicitis. Those with uncomplicated appendicitis diagnosed solely by ultrasound, and treated conservatively, were followed 18-24 m to assess treatment outcome. Management was considered successful if recurrent acute appendicitis was not observed during follow-up. Appendix diameter, wall thickness, presence of mucosal ulceration, hyperechogenic fat, free fluid, and lymph nodes were evaluated as potential discriminatory ultrasonographic predictors. T-tests, chi-square, sensitivity, specificity, and odds ratios were calculated. RESULTS: Out of 556 consecutive patients that were admitted with acute appendicitis, 180 (32%) managed conservatively. One hundred eleven (62%) imaged by US only. Ninety-two out of 111 (83%) were followed 18-24 m to assess treatment outcome, and 19/111 (17%) were lost to follow-up. Conservative management was successful in 72/92 (78.2%), with treatment failure in 20/92 (21.8%) (5/92 (5.4%) with recurrent acute appendicitis and 15/92 (16.3%) underwent appendectomy). Of the ultrasonographic features studied, mucosal ulceration demonstrated statistically significant predictive value. Fifteen out of 20 (75%) treatment failures had mucosal ulceration, compared to 21/72 (29.2%) of the patients with successful treatment (p < 0.001). This yielded a positive odds ratio of 7.3 (2.3-22.6, 95% CI), 70.8% (58.9-80.9, 95% CI) specificity, and 75% (50.9-91.3, 95% CI) sensitivity. Positive predictive value was 41.6% (31.5-52.5, 95% CI) while intact mucosa had negative predictive value of 91% (82.4-95.6, 95% CI) for conservative management success. CONCLUSION: The presence or absence of appendiceal mucosal ulceration at ultrasound can predict conservative management outcome in the setting of acute appendicitis, potentially improving pediatric patient selection for conservative management.

CT severity indices derived from low monoenergetic images at dual-energy CT may improve prediction of outcome in acute pancreatitis.

OBJECTIVES: To determine whether imaging features and severity indices using low monoenergetic DECT images improve diagnostic conspicuity and outcome prediction in acute pancreatitis compared to conventional images. METHODS: A retrospective study of patients with clinical and radiographic signs of acute pancreatitis who underwent 50 contrast-enhanced CT exams conducted on a single-source DECT was performed. Representative conventional and 50 keV-monoenergetic images were randomized and presented to four abdominal radiologists to determine preferred imaging for detecting fat stranding and parenchymal inflammation. Contrast and signal-to-noise ratios were constructed for necrotic, hypoattenuated, inflamed, and healthy parenchyma. These parameters and the CT severity index (CTSI) were compared between conventional and low monoenergetic images using paired t tests and correlated to clinical outcome. RESULTS: Although preference for conventional images was noted for subtle peri-pancreatic fat stranding (169/200 (85%) reads), there was clear preference for low monoenergetic images among all readers for pancreatic inflammation evaluation (188/200 (94%) reads). Moreover, identification of small, hypoattenuating inflammatory foci on monoenergetic images alone in 13/50 (26%) cases resulted in upstaged CTSI from mild to moderate in 7/50 (14%), associated with longer hospitalization (16 ± 17 days vs. 5 ± 2 days; p < 0.05), ICU admission, and drainage. Quantitatively, a twofold difference between normal and inflamed parenchyma attenuation was identified for monoenergetic (44.8 ± 27.6) vs. conventional (25.1 ± 14.7) images (p < 0.05). Significant increases were seen in the monoenergetic SNR and CNR compared to the conventional images (p < 0.05). CONCLUSIONS: DECT low monoenergetic images afford better tissue assessment and demarcation of inflamed pancreatic parenchyma. Additionally, they provide improved characterization of the extent parenchymal necrosis, enabling better classification that may better predict severe clinical outcomes. KEY POINTS: • DECT low monoenergetic images afford better tissue assessment and demarcation of inflamed pancreatic parenchyma and provide improved characterization of the extent parenchymal necrosis. • Qualitatively, low monoenergetic images were preferred over conventional DECT images for the evaluation of pancreatic inflammation; and quantitatively, there is a twofold difference between normal and inflamed parenchyma attenuation, SNR, and CNR between monoenergetic vs. conventional images. • Monoenergetic imaging identified additional small, hypoattenuating inflammatory foci in 26% resulting in an upstaged CT severity index in 14% associated with longer hospitalization, ICU admission, and drainage, thereby enabling better classification and better prediction of severe clinical outcomes.

Psoas Attenuation and Mortality of Elderly Patients Undergoing Nontraumatic Emergency Laparotomy.

BACKGROUND: Emergency laparotomy (EL) is an increasingly common procedure in the elderly. Factors associated with mortality in the subpopulation of frail patients have not been thoroughly investigated. Sarcopenia has been investigated as a surrogate for frailty and poor prognosis. Our primary aim was to evaluate the association between easily measured sarcopenia parameters and 30-day postoperative mortality in elderly patients undergoing EL. Length of stay (LOS) and admission to an intensive care unit were secondary end points. METHODS: We conducted a retrospective cohort study, over a 5-year period, of patients aged 65 y and older who underwent EL at a tertiary university hospital. Sarcopenia was evaluated on admission computed tomography scan by two methods, first by psoas muscle attenuation and second by the product of perpendicular cross-sectional diameters (PCSDs). The lowest quartile of PCSDs and attenuation were defined as sarcopenic and compared with the rest of the cohort. Attenuation was stratified for the use of contrast enhancement. Multivariant logistic regression was performed to determine independent risk factors. RESULTS: During the study period, 403 patients, older than 65 y, underwent EL. Of these, 283 fit the inclusion criteria and 65 (23%) patients died within 30 d of surgery. On bivariate analysis, psoas muscle attenuation, but not PCSDs, was found to be associated with 30-day mortality (OR = 2.43, 95% CI = 1.34-4.38, P = 0.003) and longer LOS (35.7 d versus 22.2 d, Δd 13.5, 95% CI = 6.4-20.7, P < 0.001). In a multivariate analysis, psoas muscle attenuation, but not PCSDs, was an independent risk factor for 30-day postoperative mortality (OR = 2.35, 95% CI = 1.16-4.76, P = 0.017) and longer LOS (Δd = 14.4, 95% CI = 7.7-21.0, P < 0.001). Neither of the sarcopenia parameters was associated with increased admission to an intensive care unit. DISCUSSION: Psoas muscle attenuation is an independent risk factor for 30-day postoperative mortality and LOS after EL in the elderly population. This measurement can inform clinicians about the operative risk and hospital resource utilization.

Hyperpolarized product selective saturating-excitations for determination of changes in metabolic reaction rates in real-time.

Investigation of hyperpolarized substrate metabolism has been showing utility in real-time determination of in-cell and in vivo enzymatic activities. Intracellular reaction rates may vary during the course of a measurement, even on the very short time scales of visibility on hyperpolarized MR, due to many factors such as the availability of the substrate and co-factors in the intracellular space. Despite this potential variation, the kinetic analysis of hyperpolarized signals typically assumes that the same rate constant (and in many cases, the same rate) applies throughout the course of the reaction as observed via the build-up and decay of the hyperpolarized signals. We demonstrate here an acquisition approach that can null the need for such an assumption and enable the detection of instantaneous changes in the rate of the reaction during an ex vivo hyperpolarized investigation, (i.e. in the course of the decay of one hyperpolarized substrate dose administered to a viable tissue sample ex vivo). This approach utilizes hyperpolarized product selective saturating-excitation pulses. Similar pulses have been previously utilized in vivo for spectroscopic imaging. However, we show here favorable consequences to kinetic rate determinations in the preparations used. We implement this acquisition strategy for studies on perfused tissue slices and develop a theory that explains why this particular approach enables the determination of changes in enzymatic rates that are monitored via the chemical conversions of hyperpolarized substrates. Real-time changes in intracellular reaction rates are demonstrated in perfused brain, liver, and xenograft breast cancer tissue slices and provide another potential differentiation parameter for tissue characterization.

Clinical and Radiologic Characteristics of Intra-Abdominal Fistulizing Crohn's Disease.

BACKGROUND: Few studies describe the radiological and laboratory characteristics of patients with Crohn's disease (CD) with intra-abdominal fistulae. OBJECTIVES: We aimed to describe a cohort of CD patients with intra-abdominal fistulae and determine characteristics associated with complex fistulae. METHODS: Data were gathered from medical records and imaging studies of patients. Evaluation included type of fistula, number of fistulae, and radiological characteristics. RESULTS: A total of 205 fistulae in 132 patients were identified with an average patient age of 31 (±12) years. The average time from CD diagnosis to fistula development was 7 years. The most common type of fistula was entero-enteric (53%). Patients with an extra-intestinal fistula presented with an average of 1.96 fistulae, compared with an average of 1.28 fistulae for those with a fistula limited to the bowel (p =0.01). Except for the number of fistula no other significant differences were observed in radiological characteristics of patients who were diagnosed with a fistula at time of CD diagnosis compared to those diagnosed with a fistula later. CONCLUSIONS: The most common CD-associated intra-abdominal fistulae are entero-enteric and entero-colonic fistulae. An extra-intestinal fistula and diagnosis of a fistula subsequent to diagnosis of CD were associated with an increased number of fistulae per patient.

VHL-Related Neuroendocrine Neoplasms And Beyond: An Israeli Specialized Center Real-Life Report.

OBJECTIVE: Von Hippel-Lindau (VHL) syndrome is a rare and complex disease. In 1996, we described a 3 generation VHL 2A kindred with 11 mutation carriers. We aim to share our experience regarding the long-term follow-up of this family and the management of all our other VHL patients focusing on frequently encountered neuroendocrine neoplasms: pheochromocytoma/paraganglioma and pancreatic neuroendocrine neoplasms (PNEN). METHODS: All VHL patients in follow-up at our tertiary center from 1980 to 2019 were identified. Clinical, laboratory, imaging, and therapeutic characteristics were retrospectively analyzed. RESULTS: We identified 32 VHL patients in 16 different families, 7/16 were classified as VHL 2 subtype. In the previously described family, the 4 initially asymptomatic carriers developed a neuroendocrine tumor; 7 new children were born, 3 of them being mutation carriers; 2 patients died, 1 due to metastatic PNEN-related liver failure. Pheochromocytoma was frequent (22/32), bilateral (13/22;59%), often diagnosed in early childhood when active screening was timely performed, associated with paraganglioma in 5/22, rarely malignant (1/22), and recurred after surgery in some cases after more than 20 years. PNEN occurred in 8/32 patients (25%), and was metastatic in 3 patients. Surgery and palliative therapy allowed relatively satisfactory outcomes. Severe disabling morbidities due to central-nervous system and ophthalmologic hemangiomas, and other rare tumors as chondrosarcoma in 2 patients and polycythemia in 1 patient were observed. CONCLUSION: A multidisciplinary approach and long-term follow-up is mandatory in VHL patients to manage the multiple debilitating morbidities and delay mortality in these complex patients.

In search of a genetic explanation for LDLc variability in an FH family: common SNPs and a rare mutation in MTTP explain only part of LDL variability in an FH family.

We previously identified a highly consanguineous familial hypercholesterolemia (FH) family demonstrating segregation of the JD Bari mutation in the LDL receptor as well as a putative cholesterol-lowering trait. We aimed to identify genes related to the latter effect. LDL cholesterol (LDLc) values were normalized for FH affectation status, age, and gender. Using genome-wide SNP data, we examined whether known SNPs gleaned from a genome-wide association study could explain the variation observed in LDLc. Four individuals with markedly reduced LDL levels underwent whole exome sequencing. After prioritizing all potential mutations, we identified the most promising candidate genes and tested them for segregation with the lowering trait. We transfected a plasmid carrying the top candidate mutation, microsomal triglyceride transfer protein (MTTP) R634C, into COS-7 cells to test enzymatic activity. The SNP score explained 3% of the observed variability. MTTP R634C showed reduced activity (49.1 nmol/ml) compared with the WT allele (185.8 nmol/ml) (P = 0.0012) and was marginally associated with reduced LDLc in FH patients (P = 0.05). Phenotypic variability in a FH pedigree can only partially be explained by a combination of common SNPs and a rare mutation and a rare variant in the MTTP gene. LDLc variability in FH patients may have nongenetic causes.

Real-time ALT and LDH activities determined in viable precision-cut mouse liver slices using hyperpolarized [1-13 C]pyruvate-Implications for studies on biopsied liver tissues.

Precision-cut liver slices (PCLS) are widely used in liver research as they provide a liver model with all liver cell types in their natural architecture. The purpose of this study was to demonstrate the use of PCLS for hyperpolarized metabolic investigation in a mouse model, for potential future application in liver biopsy cores. Fresh normal liver was harvested from six mice. 500 µm PCLS were prepared and placed in a 10 mm NMR tube in an NMR spectrometer and perfused continuously. 31 P spectra were acquired to evaluate the presence of adenosine triphosphate (ATP) and validate viability in all samples. Hyperpolarized [1-13 C]pyruvate was flushed into the NMR tube in the spectrometer. Consecutive 13 C NMR spectra were acquired immediately after the injection using both non-selective (five injections, two livers) and selective RF excitation (six injections, three livers). The 31 P spectra showed the characteristic signals of ATP, confirming the viability of the PCLS for more than 2.5 h in the spectrometer. After each of the [1-13 C]pyruvate injections, both [1-13 C]lactate and [1-13 C]alanine signals were detected. Selective RF excitation aimed at both [1-13 C]lactate and [1-13 C]alanine enabled better visualization and quantification of the metabolic activity. Using this acquisition approach only the newly formed metabolites are observed upon excitation, and their intensities relative to those of hyperpolarized pyruvate enable quantification of metabolite production rates. This rate of lactate and alanine production appeared to be constant throughout the measurement time, with alanine production about 2.3 times higher than lactate. In summary, the viability of PCLS in an NMR spectrometer was demonstrated and hyperpolarized [1-13 C]pyruvate metabolism was recorded. This study opens up the possibility of evaluating alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) activities in human liver biopsies, while preserving the tissue architecture and viability. In healthy, well-perfused liver slices the ratio of ALT to LDH activity is about 2.3.

In-cell determination of Lactate Dehydrogenase Activity in a Luminal Breast Cancer Model ⁻ ex vivo Investigation of Excised Xenograft Tumor Slices Using dDNP Hyperpolarized [1-13C]pyruvate.

[1-13C]pyruvate, the most widely used compound in dissolution-dynamic nuclear polarization (dDNP) magnetic resonance (MR), enables the visualization of lactate dehydrogenase (LDH) activity. This activity had been demonstrated in a wide variety of cancer models, ranging from cultured cells, to xenograft models, to human tumors in situ. Here we quantified the LDH activity in precision cut tumor slices (PCTS) of breast cancer xenografts. The Michigan Cancer Foundation-7 (MCF7) cell-line was chosen as a model for the luminal breast cancer type which is hormone responsive and is highly prevalent. The LDH activity, which was manifested as [1-13C]lactate production in the tumor slices, ranged between 3.8 and 6.1 nmole/nmole adenosine tri-phosphate (ATP) in 1 min (average 4.6 ± 1.0) on three different experimental set-ups consisting of arrested vs. continuous perfusion and non-selective and selective RF pulsation schemes and combinations thereof. This rate was converted to an expected LDH activity in a mass ranging between 3.3 and 5.2 µmole/g in 1 min, using the ATP level of these tumors. This indicated the likely utility of this approach in clinical dDNP of the human breast and may be useful as guidance for treatment response assessment in a large number of tumor types and therapies ex vivo.

Implementation of an institutional protocol to improve inferior vena cava utilization and outcomes.

To evaluate the impact of an institutional protocol on patterns of use and outcomes of inferior vena cava filters (IVCF). Following a multidisciplinary effort, an institutional protocol involving dedicated follow-up of patients receiving IVCF and a physician education program regarding IVCF utilization, was established. We prospectively collected data of patients who received IVCF during 2015-2016, following protocol implementation (POST group). For comparison, we reviewed records of patients who received IVCF during 2009-2014, before implementation of the institutional protocol (PRE group). In the PRE and POST groups, 76 and 38 IVCF per year were inserted respectively, with an overall decrease of 50%. IVCF were more likely to be placed for therapeutic rather than prophylactic indications in the POST compared to the PRE group (P = 0.003). Follow-up rates at our coagulation clinic were significantly higher in the POST than the PRE group (100 vs. 22.9%, P < 0.0001), as were rates of attempted retrieval: 60.5% (23/38) vs. 16.7% (76/455), P < 0.0001. Failed retrieval occurred at similar rates: 15.8% (12/76) vs. 18.2% (4/22), P = 0.75. There was a trend towards a lower thrombotic complication rate in the POST than the PRE group: 2.6 vs. 11.2%, P = 0.16. Implementation of an institutional protocol significantly decreased the use of IVCF and increased the retrieval rate. Such intervention could potentially lead to lower rates of IVCF-related complications in the future.

A Phase I Dose-Escalation Trial of Single-Fraction Stereotactic Radiation Therapy for Liver Metastases.

BACKGROUND: There is significant interest in the use of stereotactic ablative radiotherapy (SABR) as a treatment modality for liver metastases. A variety of SABR fractionation schemes are in clinical use. We conducted a phase I dose-escalation study to determine the maximum tolerated dose of single-fraction liver SABR. METHODS: Patients with liver metastases from solid tumors, for whom a critical volume dose constraint could be met, were treated with single-fraction SABR. Seven patients were enrolled to the first group, with a prescription dose of 35 Gy. Dose was then escalated to 40 Gy in a single fraction, and seven more patients were treated at this dose level. Patients were followed for toxicity and underwent serial imaging to assess lesion response and local control. RESULTS: Fourteen patients with 17 liver metastases were treated. There were no dose-limiting toxicities observed at either dose level. Nine of the 13 lesions assessable for treatment response showed a complete radiographic response to treatment; the remainder showed partial response. Local control of irradiated lesions was 100 % at a median imaging follow-up of 2.5 years. Two-year overall survival for all patients was 78 %. CONCLUSIONS: For selected patients with liver metastases, single-fraction SABR at doses of 35 and 40 Gy is tolerable and shows promising signs of efficacy at intermediate follow-up.

MC3DU-Net: a multisequence cascaded pipeline for the detection and segmentation of pancreatic cysts in MRI.

PURPOSE: Radiological detection and follow-up of pancreatic cysts in multisequence MRI studies are required to assess the likelihood of their malignancy and to determine their treatment. The evaluation requires expertise and has not been automated. This paper presents MC3DU-Net, a novel multisequence cascaded pipeline for the detection and segmentation of pancreatic cysts in MRI studies consisting of coronal MRCP and axial TSE MRI sequences. METHODS: MC3DU-Net leverages the information in both sequences by computing a pancreas Region of Interest (ROI) segmentation in the TSE MRI scan, transferring it to MRCP scan, and then detecting and segmenting the cysts in the ROI of the MRCP scan. Both the voxel-level ROI of the pancreas and the segmentation of the cysts are performed with 3D U-Nets trained with Hard Negative Patch Mining, a new technique for class imbalance correction and for the reduction in false positives. RESULTS: MC3DU-Net was evaluated on a dataset of 158 MRI patient studies with a training/validation/testing split of 118/17/23. Ground truth segmentations of a total of 840 cysts were manually obtained by expert clinicians. MC3DU-Net achieves a mean recall of 0.80 ± 0.19, a mean precision of 0.75 ± 0.26, a mean Dice score of 0.80 ± 0.19 and a mean ASSD of 0.60 ± 0.53 for pancreatic cysts of diameter > 5 mm, which is the clinically relevant endpoint. CONCLUSION: MC3DU-Net is the first fully automatic method for detection and segmentation of pancreatic cysts in MRI. Automatic detection and segmentation of pancreatic cysts in MRI can be performed accurately and reliably. It may provide a method for precise disease evaluation and may serve as a second expert reader.

Optimal CT windowing on low-monoenergetic images using a simplex algorithm-based approach for abdominal inflammatory processes.

BACKGROUND: OBJECTIVES: To determine optimal window settings for conspicuity of abdominal inflammatory processes on 50 keV low-monoenergetic images derived from dual-energy spectral CT (DECT). METHODS: A retrospective study of 30 patients with clinically proven pancreatitis (15/30) or pyelonephritis (15/30) with inflammatory lesions visible on DECT scans were selected to serve as reference populations. 50 keV low-monoenergetic images in the portal venous phase were iteratively evaluated by 6 abdominal radiologists in twenty-one different windows (7-350HU center; 120-580HU width), selected using a simplex optimization algorithm. Each reader graded the conspicuity of the parenchymal hypodense lesions and image background quality. Three-dimensional contour maps expressing the relationship between overall reader grade and window center and width were constructed and used to find the ideal window for inflammatory pancreatic and renal processes and the image background quality. Finally, 15 appendicitis cases were reviewed on optimal pancreas and kidney windows and the manufacturer recommended conventional abdominal window settings for conventional imaging. RESULTS: Convergence to optimal windowing was achieved based upon a total of 3,780 reads (21 window settings × 6 readers × 15 cases for pancreas and kidney). Highest conspicuity grade (>4.5 ± 0.0) for pancreas inflammatory lesions was seen at 116HU/430HU, whereas hypodense pyelonephritis had highest conspicuity at 290HU/570HU. This rendered an ideal "compromise" window (>4 ± 0.2) of 150HU/450HU which differed substantially from conventional manufacturer recommended settings of 50HU/380HU (2.1 ± 1.0, p = 0.00001). Appendix mucosal enhancement was best visualized at manufacturer settings. CONCLUSIONS: Optimal visualization of inflammatory processes in abdominal organs on 50 keV low-monoenergetic images may require tailored refinement of window settings.

Dual-energy CT in acute cholecystitis- features predicting culture-positive bile and outcome.

PURPOSE: Low mono-energetic CT has been shown to improve visualization of acute abdominal inflammatory processes. We aimed to determine its utility in patients with acute cholecystitis and potential added value in clinical decision making. METHODS: Sixty-seven consecutive patients with radiological signs of cholecystitis on contrast-enhanced dual-layer CT imaging were retrospectively identified over a four-year period (2/17-8/21). A ranked Likert scale was created for imaging findings present in acute cholecystitis, including gallbladder mucosal integrity and enhancement and pericholecystic liver parenchymal enhancement. These rankings were correlated with laboratory data, followed by sensitivity, specificity, and odds-ratios calculations. RESULTS: Mucosal integrity and pericholecystic liver enhancement were better seen on low-energetic images by unanimous consensus. Presence of pericholecystic liver enhancement and poorer mucosal wall integrity correlated with positive bile cultures (sensitivity: 93.8 % and 96.9 %, specificity: 37.5 and 50.0 %; odds-ratio: 9.0[1.1-68.1 95 %CI] and 31.0 [2.7-350.7 95 %CI], p = 0.017 and p ≤ 0.001) in patients undergoing cholecystostomy (n = 40/67). Moreover, binary regression modeling showed that the strongest predictor variable for bile culture positivity was the score for pericholecystic liver enhancement (Exp(B) = 0.6, P = 0.022). By contrast, other laboratory markers and other imaging findings (such as GB wall thickness) showed lower sensitivities (76-82 %), specificities (16-21 %) and odds ratios (0.2-4.4) for the prediction of infected bile. CONCLUSIONS: Pericholecystic liver enhancement and gallbladder wall integrity are better visualized on low-DECT images. These findings also potentially predict bile culture positivity in patients with cholecystitis, which may influence clinical management including the need for intervention.