Association of Maximal Extent of Resection of Contrast-Enhanced and Non-Contrast-Enhanced Tumor With Survival Within Molecular Subgroups of Patients With Newly Diagnosed Glioblastoma

Importance

Per the World Health Organization 2016 integrative classification, newly diagnosed glioblastomas are separated into isocitrate dehydrogenase gene 1 or 2 (IDH)-wild-type and IDH-mutant subtypes, with median patient survival of 1.2 and 3.6 years, respectively. Although maximal resection of contrast-enhanced (CE) tumor is associated with longer survival, the prognostic importance of maximal resection within molecular subgroups and the potential importance of resection of non-contrast-enhanced (NCE) disease is poorly understood.

Objective

To assess the association of resection of CE and NCE tumors in conjunction with molecular and clinical information to develop a new road map for cytoreductive surgery.

Design, Setting, and Participants

This retrospective, multicenter cohort study included a development cohort from the University of California, San Francisco (761 patients diagnosed from January 1, 1997, through December 31, 2017, with 9.6 years of follow-up) and validation cohorts from the Mayo Clinic (107 patients diagnosed from January 1, 2004, through December 31, 2014, with 5.7 years of follow-up) and the Ohio Brain Tumor Study (99 patients with data collected from January 1, 2008, through December 31, 2011, with a median follow-up of 10.9 months). Image accessors were blinded to patient groupings. Eligible patients underwent surgical resection for newly diagnosed glioblastoma and had available survival, molecular, and clinical data and preoperative and postoperative magnetic resonance images. Data were analyzed from November 15, 2018, to March 15, 2019.

Main Outcomes and Measures

Overall survival.

Results

Among the 761 patients included in the development cohort (468 [61.5%] men; median age, 60 [interquartile range, 51.6-67.7] years), younger patients with IDH-wild-type tumors and aggressive resection of CE and NCE tumors had survival similar to that of patients with IDH-mutant tumors (median overall survival [OS], 37.3 [95% CI, 31.6-70.7] months). Younger patients with IDH-wild-type tumors and reduction of CE tumor but residual NCE tumors fared worse (median OS, 16.5 [95% CI, 14.7-18.3] months). Older patients with IDH-wild-type tumors benefited from reduction of CE tumor (median OS, 12.4 [95% CI, 11.4-14.0] months). The results were validated in the 2 external cohorts. The association between aggressive CE and NCE in patients with IDH-wild-type tumors was not attenuated by the methylation status of the promoter region of the DNA repair enzyme O6-methylguanine-DNA methyltransferase.

Conclusions and Relevance

This study confirms an association between maximal resection of CE tumor and OS in patients with glioblastoma across all subgroups. In addition, maximal resection of NCE tumor was associated with longer OS in younger patients, regardless of IDH status, and among patients with IDH-wild-type glioblastoma regardless of the methylation status of the promoter region of the DNA repair enzyme O6-methylguanine-DNA methyltransferase. These conclusions may help reassess surgical strategies for individual patients with newly diagnosed glioblastoma.

Frontal lobe degeneration: clinical, neuropsychological, and SPECT characteristics

The clinical, neuropsychological, and cerebral blood flow characteristics of eight patients with frontal lobe degeneration (FLD) were studied. Social withdrawal and behavioral disinhibition were the earliest and most common clinical presentations, and psychiatric symptoms typically preceded the onset of dementia by several years. Neuropsychological testing showed selective impairment of frontal and memory tasks with relative sparing of attention, language, and visuospatial skills. Single-photon emission computerized tomography demonstrated frontal and temporal hypoperfusion with relative sparing of parietal and occipital blood flow. Previous studies suggest that the neuropathologic findings in patients with FLD are varied; some demonstrate frontal gliosis, neuronal loss, and Pick bodies while others show only gliosis and neuronal loss.

Regional xenon 133 cerebral blood flow and cerebral technetium 99m HMPAO uptake in unmedicated patients with obsessive-compulsive disorder and matched normal control subjects. Determination by high-resolution single-photon emission computed tomography

We measured regional cerebral blood flow (rCBF) with the xenon 133 (133Xe) inhalation method and with regional cerebral uptake of technetium 99m d,l-hexamethyl propyleneamine oxime (99mTc-HMPAO) by single-photon emission computed tomography in 10 adult male patients with obsessive-compulsive disorder (OCD) and in 10 age-matched adult male normal controls. With the 133Xe method, there were no significant differences in cortical or basal ganglia blood flow between the patients with OCD and their matched controls. In the patients, there was a positive relationship between rCBF and the severity of both obsessive and compulsive symptoms (average r = .48). These rCBF findings were consistent with those of earlier reports of increased rCBF in patients with OCD who were undergoing imaginal flooding and who had exacerbation of symptoms following m-CPP administration. 99mTc-HMPAO is a lipophilic molecule that crosses the blood-brain barrier and is converted to a hydrophilic form that is trapped in the brain. The amount that is trapped is determined primarily by blood flow, but also by membrane permeability and kinetics of conversion of the 99mTc-HMPAO to the hydrophilic form. Compared with their matched controls, the patients with OCD had significantly increased 99mTc-HMPAO uptake in the high dorsal parietal cortex bilaterally, in the left posterofrontal cortex, and in the orbital frontal cortex bilaterally. Possible explanations include (1) increased rCBF that was not detected with 133Xe, (2) increased permeability of the blood-brain barrier and/or cell membranes, and (3) increased conversion and trapping of the lipophilic, injected form of 99mTc-HMPAO in these regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Colonic motility and transit in health and ulcerative colitis

Preprandial and postprandial colonic motility and transit (scintigraphy), with respect to the splenic flexure, were studied in 10 patients with ulcerative colitis and in 9 healthy subjects. The healthy subjects had a postprandial increase in intraluminal pressure that was significantly (P less than 0.03) greater in the descending colon than in other regions of the colon. In ulcerative colitis, the pressure was decreased in all regions compared with healthy subjects, with no significant pressure gradient among different regions. In normal subjects, transit was quiescent during fasting; eating stimulated both antegrade and retrograde transit. In ulcerative colitis, transit was variable before as well as after the meal. Both healthy subjects and patients with ulcerative colitis had more rapid emptying from the splenic flexure into the sigmoid than into the transverse colon. More frequent, low-amplitude, postprandial propagating contractions occurred in ulcerative colitis (P less than 0.05) than in healthy subjects. Propagating contractions were always antegrade and caused a rapid movement of the tracer into the sigmoid. In conclusion, ulcerative colitis is characterized by (a) decreased contractility, (b) increased low-amplitude propagating contractions, and (c) variable transit. These disturbances may accentuate the diarrhea in ulcerative colitis.

Cerebral perfusion and neuropsychological consequences of chronic cocaine use

Research indicates that cocaine significantly constricts the cerebral vasculature and can lead to ischemic brain infarction. Long-term effects of intermittent or casual cocaine use in patients without symptoms of stroke or transient ischemic attack were investigated. Single-photon emission computed tomography with xenon-133 and [99mTc]hexamethylpropyleneamine oxime, magnetic resonance imaging, and selected neuropsychological measures were used to study cerebral perfusion, brain morphology, and cognitive functioning. Patients were drug free for at least 6 months before evaluation. All showed regions of significant cerebral hypoperfusion in the frontal, periventricular, and/or temporal-parietal areas. Deficits in attention, concentration, new learning, visual and verbal memory, word production, and visuomotor integration were observed. This study indicates that long-term cocaine use may produce sustained brain perfusion deficits and persistent neuropsychological compromise in some subgroups of cocaine-abusing patients.

Federated learning enables big data for rare cancer boundary detection

Although machine learning (ML) has shown promise across disciplines, out-of-sample generalizability is concerning. This is currently addressed by sharing multi-site data, but such centralization is challenging/infeasible to scale due to various limitations. Federated ML (FL) provides an alternative paradigm for accurate and generalizable ML, by only sharing numerical model updates. Here we present the largest FL study to-date, involving data from 71 sites across 6 continents, to generate an automatic tumor boundary detector for the rare disease of glioblastoma, reporting the largest such dataset in the literature (n = 6, 314). We demonstrate a 33% delineation improvement for the surgically targetable tumor, and 23% for the complete tumor extent, over a publicly trained model. We anticipate our study to: 1) enable more healthcare studies informed by large diverse data, ensuring meaningful results for rare diseases and underrepresented populations, 2) facilitate further analyses for glioblastoma by releasing our consensus model, and 3) demonstrate the FL effectiveness at such scale and task-complexity as a paradigm shift for multi-site collaborations, alleviating the need for data-sharing.

Effect of eating on colonic motility and transit in patients with functional diarrhea. Simultaneous scintigraphic and manometric evaluations

The aim of this study was to correlate colonic motility with transit in 8 patients with functional diarrhea compared to 12 healthy subjects. Intraluminal pressure was measured with perfused catheter ports in the transverse colon, splenic flexure, and descending and sigmoid colons. Transit of the luminal contents was measured by following the movement of 99mTC-diethylenetriaminepentaacetic acid instilled as a bolus in the splenic flexure. In patients with diarrhea, the intraluminal marker moved in and out of the transverse and sigmoid colon regions of interest during fasting, unlike healthy subjects, in whom the marker remained in the splenic flexure. After eating, radioactivity immediately increased in both the transverse and sigmoid colons in healthy subjects. In the patients with diarrhea, eating did not alter the marker movement into the different regions of the colon compared with fasting. Within 100 minutes of eating, the intraluminal marker almost disappeared from the regions of interest in patients with diarrhea. Postprandial colonic nonpropagating contractions increased in each region of the colon in healthy subjects; there was only a small postprandial increase in colonic motility in patients with diarrhea. However, the numbers of fasting and postprandial propagating contractions were increased in patients with diarrhea compared with healthy subjects (P less than 0.02). Each propagating contraction moved more tracer in patients with diarrhea than in healthy subjects (P less than 0.05). These studies suggest that (a) in patients with diarrhea, the fluctuation of marker in both transverse and sigmoid colons during the fasting and postprandial periods is associated with decreased nonsegmenting contractions and frequent propagating contractions; and (b) in healthy subjects, the intraluminal marker moved after eating because of a pressure gradient caused by nonpropagating contractions.

Regional 133xenon cerebral blood flow and cerebral 99mTc-HMPAO uptake in patients with obsessive-compulsive disorder before and during treatment

We previously reported increased regional cerebral cortical uptake and decreased caudate nucleus uptake of 99mTc-HMPAO in patients with obsessive-compulsive disorder(OCD) before treatment compared to matched normal controls. In the present study, we determined whether or not these changes persisted during treatment. Single-photon emission computed tomography was used to measure regional cerebral blood flow (rCBF) by 133Xe inhalation and cerebral uptake of 99mTc-HMPAO in eight adult male OCD patients before and during treatment with chlomipramine, and in eight age-matched normal male controls. With 133Xe, there were no significant differences in rCBF between patients with OCD and their matched controls, and no significant differences in rCBF in the patients before and during treatment. Significantly increased HMPAO uptake in the orbital frontal cortex, posterofrontal cortex, and high dorsal parietal cortex bilaterally occurred in the OCD patients before treatment compared to their matched controls, and there were significant reductions of HMPAO uptake, into the normal range, in all these areas in the patients during treatment. Significantly reduced HMPAO uptake in the caudate nucleus bilaterally occurred in the patients before treatment compared to their matched controls, and these reductions persisted during treatment. This study provides additional support for the involvement of both the orbital frontal cortex and the caudate nuclei in the pathophysiology of OCD.

Association between postprandial changes in colonic intraluminal pressure and transit

The aim of this study was to correlate the movement of colonic luminal contents with the changes in intraluminal pressure. Studies were performed in 9 healthy volunteers. Intraluminal pressure was measured with perfused catheter ports in the transverse, splenic flexure, descending, and sigmoid colon. Movement of the luminal contents was measured by following the movement of technetium 99m-ethylenetriamine-pentaacetic acid that was instilled as a bolus in the splenic flexure. During fasting there was very little change in pressure or in the movement of intraluminal contents. After eating a 1000-kcal meal, the tracer moved from the splenic flexure into the transverse colon and the sigmoid colon. Nonpropagating colonic motor activity increased in all colonic segments immediately after eating the meal (p less than 0.05). The increase in motility was significantly greater in the descending colon than in the transverse and sigmoid colon (p less than 0.05). In one-half of the subjects propagating contractions occurred postprandially. The movement of the intraluminal tracer occurred during both types of motility. The nonpropagating contractions were associated with a gradual movement of the luminal contents. The direction of the movement of the contents was determined by the differences in pressure in the different segments of the colon. The propagating contractions were associated with a rapid movement of intraluminal contents. These studies suggest that (a) colonic motility and transit are quiescent during fasting and (b) the transverse colon acts as a mixing and storage area, as retrograde transit into the transverse colon is the characteristic postprandial pattern.

Cerebral abnormalities in myotonic dystrophy. Cerebral blood flow, magnetic resonance imaging, and neuropsychological tests

OBJECTIVE

To study cerebral abnormalities in myotonic dystrophy (MD) and determine the different patterns of cerebral function in patients with MD with maternal (mMD) vs paternal (pMD) inheritance.

DESIGN

Patients with MD and normal controls were studied with neuropsychological testing, magnetic resonance imaging, and single photon emission computed tomography.

SETTING

Studies were done at Harbor-UCLA Medical Center, Torrance, Calif.

PATIENTS AND OTHER PARTICIPANTS

Twenty-two consecutive-patients with MD, 11 of whom had pMD and eight mMD, and 10 normal controls were studied. Diagnoses were made on the basis of family history, electromyography, and clinical examinations. Normal subjects in the same age distribution were studied for comparisons.

RESULTS

We found significantly lower neuropsychological performance and cerebral blood flow in the patients with MD compared with the controls. Patients with mMD had statistically lower scores on IQ tests and more extensive cerebral hypoperfusion when compared with those with pMD. Changes in cerebral blood flow were most severe in the frontal and temporoparietal association cortex. Cerebral blood blow measures strongly correlated with IQ.

CONCLUSIONS

Patients with mMD had earlier onset of disease and lower IQs than the pMD group. The pattern of cerebral perfusion in the mMD group was consistent with a diffuse brain injury, while cerebral perfusion in pMD showed more minor changes. These findings emphasize the cognitive differences between mMD and pMD.

Temozolomide-induced hypermutation is associated with distant recurrence and reduced survival after high-grade transformation of low-grade IDH-mutant gliomas

BACKGROUND

Chemotherapy improves overall survival after surgery and radiotherapy for newly diagnosed high-risk IDH-mutant low-grade gliomas, but a proportion of patients treated with temozolomide (TMZ) will develop recurrent tumors with TMZ-induced hypermutation. We aimed to determine the prevalence of TMZ-induced hypermutation at recurrence and prognostic implications.

METHODS

We sequenced recurrent tumors from 82 patients with initially low-grade IDH-mutant gliomas who underwent re-operation and correlated hypermutation status with grade at recurrence and subsequent clinical outcomes.

RESULTS

Hypermutation was associated with high-grade disease at the time of re-operation (OR 12.0 95% CI 2.5-115.5, p=0.002) and was identified at transformation in 57% of recurrent LGGs previously exposed to TMZ. After anaplastic (grade III) transformation, hypermutation was associated with shorter survival on univariate and multivariate analysis (HR 3.4, 95% CI 1.2-9.9, p=0.024), controlling for tumor grade, subtype, age, and prior radiotherapy. The effect of hypermutation on survival after transformation was validated in an independent, published dataset. Hypermutated (HM) tumors were more likely to develop discontiguous foci of disease in the brain and spine (p=0.003). To estimate the overall incidence of high-grade transformation among low-grade IDH-mutant tumors, data from a phase II trial of TMZ for LGG were analyzed. 8-year transformation-free survival was 53.8% (95% CI 42.8-69.2) and 61% of analyzed transformed cases were HM.

CONCLUSIONS

TMZ-induced hypermutation is a common event in transformed LGG previously treated with TMZ, and is associated with worse prognosis and development of discontiguous disease after recurrence. These findings impact tumor classification at recurrence, prognostication, and clinical trial design.

Comparison of thallium-201 and technetium-99m hexakis 2-methoxyisobutyl isonitrile single-photon emission computed tomography for estimating the extent of myocardial ischemia and infarction in coronary artery disease

Single-photon emission computed tomography (SPECT) using thallium-201 (Tl-201) was compared with technetium-99m hexakis 2-methoxyisobutyl isonitrile (Tc-99m MIBI) in 24 patients with coronary artery diseaes. Patients exercised to the same work load as each isotope was studied. Normal and hypoperfused left ventricular mass was determined with an automated method. Estimated total left ventricular mass was similar for both stress/redistribution Tl-201 and stress/rest Tc-99m MIBI images. The mean estimated defect size in the redistribution Tl-201 images was 32 +/- 34.7 vs 33 +/- 38.4 g in the resting Tc-99m MIBI studies (difference not significant). The individual determinations of defect mass were highly correlated (r = 0.93; p less than 0.0001). Estimated defect size in the stress Tl-201 images (52 +/- 46.2 g) was significantly larger than the exercise Tc-99m MIBI estimates of defect mass (42 +/- 39.9 g; p less than 0.05). A linear correlation existed between stress thallium and technetium estimates of defect size (r = 0.85) but 15 of 24 Tc-99m MIBI defects were smaller than the Tl-201 defects. Partial redistribution of Tc-99m MIBI could explain the discordance. Stress Tc-99m MIBI SPECT defect size determined by visual interpretation or by the use of isocount analysis may be smaller than what is seen with stress Tl-201 SPECT.

Cisapride in children with chronic intestinal pseudoobstruction. An acute, double-blind, crossover, placebo-controlled trial

To assess the effect of cisapride on gastrointestinal motility and gastric emptying in children with chronic intestinal pseudoobstruction, 20 children (mean age, 4.9 years; 14 female and 6 male) who required special means of alimentation or who had severe symptoms confirmed by diary during 2 weeks before the study were studied. A motility catheter with recording sites in the antrum and duodenum was placed on the first day of the study and remained in place until the end of the 5-day study. Cisapride (0.3 mg/kg PO t.i.d.) or placebo was given in double-blind randomized crossover fashion, with a 2-day "washout" interval. Antroduodenal motility was recorded on days 2 and 5. Recording consisted of 4 hours of fasting and 2 hours after a complex liquid meal labeled with 99mTc. Gastric emptying was assessed for 1 hour after the meal. Based on manometry, 16 patients had neuropathic and 4 patients had myopathic disorders. Cisapride had no effect on the discrete, qualitative abnormalities found in individual records. Cisapride increased the postprandial duodenal motility index from 1180 +/- 256 mm Hg/30 min after placebo to 2385 +/- 430 mm Hg/30 min (P less than 0.05) but had no significant effect on the antral motility index. Cisapride did not alter the profound delay in gastric emptying; time to reach 50% of initial activity (T1/2) was 105 +/- 20 vs. 93 +/- 19 minutes and percentage of retention after 60 minutes (R60) 56% +/- 4% vs. 58% +/- 4% in control vs. cisapride, respectively. In summary, in children with chronic intestinal pseudoobstruction, cisapride increased postprandial duodenal motility but did not improve gastric emptying.

Interactive Effects of Molecular, Therapeutic, and Patient Factors on Outcome of Diffuse Low-Grade Glioma

PURPOSE

In patients with diffuse low-grade glioma (LGG), the extent of surgical tumor resection (EOR) has a controversial role, in part because a randomized clinical trial with different levels of EOR is not feasible.

METHODS

In a 20-year retrospective cohort of 392 patients with IDH-mutant grade 2 glioma, we analyzed the combined effects of volumetric EOR and molecular and clinical factors on overall survival (OS) and progression-free survival by recursive partitioning analysis. The OS results were validated in two external cohorts (n = 365). Propensity score analysis of the combined cohorts (n = 757) was used to mimic a randomized clinical trial with varying levels of EOR.

RESULTS

Recursive partitioning analysis identified three survival risk groups. Median OS was shortest in two subsets of patients with astrocytoma: those with postoperative tumor volume (TV) > 4.6 mL and those with preoperative TV > 43.1 mL and postoperative TV ≤ 4.6 mL. Intermediate OS was seen in patients with astrocytoma who had chemotherapy with preoperative TV ≤ 43.1 mL and postoperative TV ≤ 4.6 mL in addition to oligodendroglioma patients with either preoperative TV > 43.1 mL and residual TV ≤ 4.6 mL or postoperative residual volume > 4.6 mL. Longest OS was seen in astrocytoma patients with preoperative TV ≤ 43.1 mL and postoperative TV ≤ 4.6 mL who received no chemotherapy and oligodendroglioma patients with preoperative TV ≤ 43.1 mL and postoperative TV ≤ 4.6 mL. EOR ≥ 75% improved survival outcomes, as shown by propensity score analysis.

CONCLUSION

Across both subtypes of LGG, EOR beginning at 75% improves OS while beginning at 80% improves progression-free survival. Nonetheless, maximal resection with preservation of neurological function remains the treatment goal. Our findings have implications for surgical strategies for LGGs, particularly oligodendroglioma.

(99m)Tc sestamibi breast imaging for the examination of patients with dense and fatty breasts: multicenter study

PURPOSE

To evaluate the accuracy of scintimammography as an adjunct to physical examination and mammography in the detection of breast cancer in women with dense and fatty breasts.

MATERIALS AND METHODS

A total of 558 women were prospectively enrolled from 42 centers in North America. Images were interpreted by readers blinded to the subjects' clinical history, mammographic findings, and other test results. The Breast Imaging Reporting and Data System classification was used to describe breast density. Parenchymal patterns of "heterogeneously dense" and "extremely dense" were used to classify breasts as dense, whereas "almost entirely fat" and "numerous vague densities" defined fatty breasts. Between-group differences were evaluated with the 2 test for categorical variables and Student t test for continuous variables. Accuracy of scintimammography was assessed against the core laboratory histopathologic evaluation, the standard. The 95% CIs around point estimates of sensitivity, specificity, and positive and negative predictive values were calculated with the normal approximation to the binomial distribution.

RESULTS

The analyses were based on 580 breasts with an abnormality; 276 (48%) breasts were dense and 228 had a malignant lesion. Diagnostic properties for scintimammography of fatty versus dense breasts were, respectively, sensitivity, 72% versus 70%; specificity, 80% versus 78%; positive predictive value, 72% versus 67%; negative predictive value, 81% versus 81%; and accuracy, 77% versus 75% (all not significant). Scintimammography led to similar and significant changes in the posttest likelihood of cancer for both dense and fatty breasts.

CONCLUSION

The diagnostic accuracy of scintimammography is not affected by breast density.

Recovery of testicular blood flow following ligation of testicular vessels

To determine whether initial ligation of the testicular vessels of the high undescended testis followed by a delayed secondary orchiopexy is a viable alternative to the classical Fowler-Stephens procedure, a series of preliminary experiments were conducted in the rat in which testicular blood flow was measured by the 133xenon washout technique before, and 1 hour and 30 days after ligation of the vessels. In addition, testicular histology, and testis and sex-accessory tissue weights were measured in 6 control, 6 sham operated and 6 testicular vessel ligated rats 54 days after vessel ligation. The data demonstrate that ligation and division of the testicular blood vessels produce an 80 per cent decrease in testicular blood flow 1 hour after ligation of the vessels. However, 30 days later testis blood flow returns to the control and pre-treatment value. There were no significant changes in testis or sex-accessory tissue weights 54 days after vessel ligation. Histologically, 4 of the surgically operated testes demonstrated necrosis of less than 25 per cent of the seminiferous tubules while 1 testis demonstrated more than 75 per cent necrosis. The rest of the tubules in all 6 testes demonstrated normal spermatogenesis. From this study we conclude that initial testicular vessel ligation produces an immediate decrease in testicular blood flow but with time the collateral vessels are able to compensate and return the testis blood flow to its normal pre-treatment value. These preliminary observations lend support for the concept that initial ligation of the testicular vessels followed by a delayed secondary orchiopexy in patients with a high undescended testis may be a possible alternative to the classical Fowler-Stephens approach.

Control of oxidative reactions of hemoglobin in the design of blood substitutes: role of the ascorbate-glutathione antioxidant system

Uncontrolled oxidative reactions of hemoglobin (Hb) are still the main unresolved problem for Hb-based blood substitute developers. Spontaneous oxidation of acellular ferrous Hb into a nonfunctional ferric Hb generates superoxide anion. Hydrogen peroxide, formed after superoxide anion dismutation, may react with ferrous/ferric Hb to produce toxic ferryl Hb, fluorescent heme degradation products, and/or protein-based free radicals. In the presence of free iron released from heme, superoxide anion and hydrogen peroxide might react via the Haber-Weiss and Fenton reactions to generate the hydroxyl radical. These highly reactive oxygen and heme species may not only be involved in shifting the cellular redox balance to the oxidized state that facilitates signal transduction and pro-inflammatory gene expression, but could also be involved in cellular and organ injury, and generation of vasoactive compounds such as isoprostanes and angiotensins. It is believed that these toxic species may be formed after administration of Hb-based blood substitutes, particularly in ischemic patients with a diminished ability to control oxidative reactions. Although varieties of antioxidant strategies have been suggested, this in vitro study examined the ability of the ascorbate-glutathione antioxidant system in preventing Hb oxidation and formation of its ferryl intermediate. The results suggest that although ascorbate is effective in reducing the formation of ferryl Hb, glutathione protects heme against excessive oxidation. Ascorbate without glutathione failed to protect the red blood cell membranes against Hb/hydrogen peroxide-mediated peroxidation. This study provides evidence that the ascorbate-glutathione antioxidant system is essential in attenuation of the pro-oxidant potential of redox active acellular Hbs, and superior to either ascorbate or glutathione alone.

Hepatic perfusion before and after the transjugular intrahepatic portosystemic shunt procedure: impact on survival

PURPOSE

This study correlates transjugular intrahepatic portosystemic shunt (TIPS) mortality with flow patterns in the cirrhotic liver.

MATERIALS AND METHODS

Twenty-seven TIPS patients and 10 control subjects were used for this study. The authors evaluated hepatic perfusion with venous injections of Tc-99m pertechnetate before and after TIPS. Hepatic time-activity curves were analyzed for type and amount of liver perfusion. These parameters were correlated with survival for a mean follow-up of 18 months.

RESULTS

The mean arterial contribution to liver blood flow was 25.4% in the normal control patients, 39.9% in patients prior to TIPS, and increased to 48.3% after TIPS. Although the proportion of arterial supply to the cirrhotic liver varied widely, TIPS mortality did not correlate with the preprocedure hepatic artery/portal venous perfusion ratio. However, patients with both an "arterialized" flow pattern and low total hepatic perfusion had higher mortality, with a mean survival of 2 months compared to patients with a more favorable perfusion profile (mean survival, 28.4 months).

CONCLUSIONS

The proportion of arterial perfusion to the liver before TIPS did not affect survival. However, patients with a combination of reduced total hepatic perfusion and an arterial flow pattern had poorer survival, suggesting that both the quantity and quality of hepatic perfusion predicts TIPS outcome.

Upfront Biology-Guided Therapy in Diffuse Intrinsic Pontine Glioma: Therapeutic, Molecular, and Biomarker Outcomes from PNOC003

PURPOSE

PNOC003 is a multicenter precision medicine trial for children and young adults with newly diagnosed diffuse intrinsic pontine glioma (DIPG).

PATIENTS AND METHODS

Patients (3-25 years) were enrolled on the basis of imaging consistent with DIPG. Biopsy tissue was collected for whole-exome and mRNA sequencing. After radiotherapy (RT), patients were assigned up to four FDA-approved drugs based on molecular tumor board recommendations. H3K27M-mutant circulating tumor DNA (ctDNA) was longitudinally measured. Tumor tissue and matched primary cell lines were characterized using whole-genome sequencing and DNA methylation profiling. When applicable, results were verified in an independent cohort from the Children's Brain Tumor Network (CBTN).

RESULTS

Of 38 patients enrolled, 28 patients (median 6 years, 10 females) were reviewed by the molecular tumor board. Of those, 19 followed treatment recommendations. Median overall survival (OS) was 13.1 months [95% confidence interval (CI), 11.2-18.4] with no difference between patients who followed recommendations and those who did not. H3K27M-mutant ctDNA was detected at baseline in 60% of cases tested and associated with response to RT and survival. Eleven cell lines were established, showing 100% fidelity of key somatic driver gene alterations in the primary tumor. In H3K27-altered DIPGs, TP53 mutations were associated with worse OS (TP53mut 11.1 mo; 95% CI, 8.7-14; TP53wt 13.3 mo; 95% CI, 11.8-NA; P = 3.4e-2), genome instability (P = 3.1e-3), and RT resistance (P = 6.4e-4). The CBTN cohort confirmed an association between TP53 mutation status, genome instability, and clinical outcome.

CONCLUSIONS

Upfront treatment-naïve biopsy provides insight into clinically relevant molecular alterations and prognostic biomarkers for H3K27-altered DIPGs.

Denoising of hyperpolarized 13 C MR images of the human brain using patch-based higher-order singular value decomposition

PURPOSE

To improve hyperpolarized ¹³ C (HP-¹³ C) MRI by image denoising with a new approach, patch-based higher-order singular value decomposition (HOSVD).

METHODS

The benefit of using a patch-based HOSVD method to denoise dynamic HP-¹³ C MR imaging data was investigated. Image quality and the accuracy of quantitative analyses following denoising were evaluated first using simulated data of [1-¹³ C]pyruvate and its metabolic product, [1-¹³ C]lactate, and compared the results to a global HOSVD method. The patch-based HOSVD method was then applied to healthy volunteer HP [1-¹³ C]pyruvate EPI studies. Voxel-wise kinetic modeling was performed on both non-denoised and denoised data to compare the number of voxels quantifiable based on SNR criteria and fitting error.

RESULTS

Simulation results demonstrated an 8-fold increase in the calculated SNR of [1-¹³ C]pyruvate and [1-¹³ C]lactate with the patch-based HOSVD denoising. The voxel-wise quantification of k_PL (pyruvate-to-lactate conversion rate) showed a 9-fold decrease in standard errors for the fitted k_PL after denoising. The patch-based denoising performed superior to the global denoising in recovering k_PL information. In volunteer data sets, [1-¹³ C]lactate and [¹³ C]bicarbonate signals became distinguishable from noise across captured time points with over a 5-fold apparent SNR gain. This resulted in >3-fold increase in the number of voxels quantifiable for mapping k_PB (pyruvate-to-bicarbonate conversion rate) and whole brain coverage for mapping k_PL .

CONCLUSIONS

Sensitivity enhancement provided by this denoising significantly improved quantification of metabolite dynamics and could benefit future studies by improving image quality, enabling higher spatial resolution, and facilitating the extraction of metabolic information for clinical research.

Neuropsychiatric effects of cocaine: SPECT measurements

Cocaine causes serious neurologic and neuropsychiatric complications. Cocaine-induced seizures are common and appear to be due to the local anaesthetic actions of this compound. Cocaine induced stroke has varied mechanisms. With ischemic stroke there is severe vasospasm induced by rises in brain catecholamines. These changes can persist for many weeks and can be demonstrated using single-photon emission computerized tomography (SPECT). In many patients with psychiatric symptoms such as psychosis or mania, SPECT demonstrates similar changes in cerebral blood flow. In fact, some of the psychiatric symptoms induced by cocaine may be due to decreases in cerebral blood flow. In cocaine abuse, treatment strategies based on decreasing cerebral vasospasm need to be developed.

Spectrum of Clinical Presentations, Imaging Findings, and HLA Types in Immune Checkpoint Inhibitor-Induced Hypophysitis

Context

Hypophysitis is a known immune-related adverse event (irAE) of immune checkpoint inhibitors (CPIs), commonly associated with CTLA-4 inhibitors and less often with PD-1/PD-L1 inhibitors.

Objective

We aimed to determine clinical, imaging, and HLA characteristics of CPI-induced hypophysitis (CPI-hypophysitis).

Methods

We examined the clinical and biochemical characteristics, magnetic resonance imaging (MRI) of the pituitary, and association with HLA type in patients with CPI-hypophysitis.

Results

Forty-nine patients were identified. Mean age was 61.3 years, 61.2% were men, 81.6% were Caucasian, 38.8% had melanoma, and 44.5% received PD-1/PD-L1 inhibitor monotherapy while the remainder received CTLA-4 inhibitor monotherapy or CTLA-4/PD-1 inhibitor combination therapy. A comparison of CTLA-4 inhibitor exposure vs PD-1/PD-L1 inhibitor monotherapy revealed faster time to CPI-hypophysitis (median 84 vs 185 days, P < .01) and abnormal pituitary appearance on MRI (odds ratio 7.00, P = .03). We observed effect modification by sex in the association between CPI type and time to CPI-hypophysitis. In particular, anti-CTLA-4 exposed men had a shorter time to onset than women. MRI changes of the pituitary were most common at the time of hypophysitis diagnosis (55.6% enlarged, 37.0% normal, 7.4% empty or partially empty) but persisted in follow-up (23.8% enlarged, 57.1% normal, 19.1% empty or partially empty). HLA typing was done on 55 subjects; HLA type DQ0602 was over-represented in CPI-hypophysitis relative to the Caucasian American population (39.4% vs 21.5%, P = 0.01) and CPI population.

Conclusion

The association of CPI-hypophysitis with HLA DQ0602 suggests a genetic risk for its development. The clinical phenotype of hypophysitis appears heterogenous, with differences in timing of onset, changes in thyroid function tests, MRI changes, and possibly sex related to CPI type. These factors may play an important role in our mechanistic understanding of CPI-hypophysitis.

Correlations between SPECT regional cerebral blood flow and psychometric testing in patients with Alzheimer's disease

Thirty-nine patients with probable Alzheimer's disease (AD) were studied with [99mTc]HMPAO SPECT and a standardized neuropsychological battery testing intellect, memory, attention, language, motor and praxis functions, and depression. Spearman rank correlations and multivariate regression analyses were performed to correlate quantitative regional perfusion deficits to these tests. Patients were found to have decreased perfusion of left frontal, parietal, and temporal regions relative to right. WAB repetition scores and bilateral temporal flow were significantly correlated (P < 0.01). Correlations between visual memory and bilateral temporal flow and those between Mini-Mental State/ Geriatric Depression Scale scores and bihemispheric flow approached significance. Although in this study regional cerebral blood flow was relatively insensitive to neuroanatomical abnormalities underlying specific cognitive deficits, it may have some specificity for identifying the language disorder in AD.

Long-term effects of prepubertal testicular vessel ligation on testicular function in the rat

To determine the effects of unilateral testicular vein and artery ligation in the immature rat on the function and final location of the testis at adulthood, 10-day-old male rats underwent either a sham operation or unilateral ligation of these vessels of the still undescended testis. Testicular location, blood flow, size and histology as well as ventral prostate weights were measured 50 days later at adulthood. At age 60 days, it was determined that all testes were descended into the scrotum, and there were no differences in testis and ventral prostate weights, intratesticular sperm counts and mean seminiferous tubular area between the control and sham operated animals. However, there was an 18% reduction in testicular blood flow (ml. per 100 gm. per minute +/- standard error of mean) in the operated animals when compared to the sham (20.43 +/- 1.10 versus 16.69 +/- 0.74, p less than 0.02). These data indicate that although there is a slight but significant reduction in testicular blood flow at adulthood when the testicular artery and vein are ligated early in life, this diminution is not sufficient to alter the ultimate location, testicular weight and spermatogenic function of the testis. This would suggest that after ligation of the main testicular vessels to the immature testis, the collateral blood supply is able to compensate with time to allow normal growth and development of the testis. These experimental observations provide additional support for the 2-staged approach to the high undescended testis whereby the testicular vessels are initially ligated and a subsequent procedure is performed to place the undescended testis into the scrotum.

Association of partial T2-FLAIR mismatch sign and isocitrate dehydrogenase mutation in WHO grade 4 gliomas: results from the ReSPOND consortium

PURPOSE

While the T2-FLAIR mismatch sign is highly specific for isocitrate dehydrogenase (IDH)-mutant, 1p/19q-noncodeleted astrocytomas among lower-grade gliomas, its utility in WHO grade 4 gliomas is not well-studied. We derived the partial T2-FLAIR mismatch sign as an imaging biomarker for IDH mutation in WHO grade 4 gliomas.

METHODS

Preoperative MRI scans of adult WHO grade 4 glioma patients (n = 2165) from the multi-institutional ReSPOND (Radiomics Signatures for PrecisiON Diagnostics) consortium were analyzed. Diagnostic performance of the partial T2-FLAIR mismatch sign was evaluated. Subset analyses were performed to assess associations of imaging markers with overall survival (OS).

RESULTS

One hundred twenty-one (5.6%) of 2165 grade 4 gliomas were IDH-mutant. Partial T2-FLAIR mismatch was present in 40 (1.8%) cases, 32 of which were IDH-mutant, yielding 26.4% sensitivity, 99.6% specificity, 80.0% positive predictive value, and 95.8% negative predictive value. Multivariate logistic regression demonstrated IDH mutation was significantly associated with partial T2-FLAIR mismatch (odds ratio [OR] 5.715, 95% CI [1.896, 17.221], p = 0.002), younger age (OR 0.911 [0.895, 0.927], p < 0.001), tumor centered in frontal lobe (OR 3.842, [2.361, 6.251], p < 0.001), absence of multicentricity (OR 0.173, [0.049, 0.612], p = 0.007), and presence of cystic (OR 6.596, [3.023, 14.391], p < 0.001) or non-enhancing solid components (OR 6.069, [3.371, 10.928], p < 0.001). Multivariate Cox analysis demonstrated cystic components (p = 0.024) and non-enhancing solid components (p = 0.003) were associated with longer OS, while older age (p < 0.001), frontal lobe center (p = 0.008), multifocality (p < 0.001), and multicentricity (p < 0.001) were associated with shorter OS.

CONCLUSION

Partial T2-FLAIR mismatch sign is highly specific for IDH mutation in WHO grade 4 gliomas.