Quantitative susceptibility mapping using plug-and-play alternating direction method of multipliers

Quantitative susceptibility mapping employs regularization to reduce artifacts, yet many recent denoisers are unavailable for reconstruction. We developed a plug-and-play approach to QSM reconstruction (PnP QSM) and show its flexibility using several patch-based denoisers. We developed PnP QSM using alternating direction method of multiplier framework and applied collaborative filtering denoisers. We apply the technique to the 2016 QSM Challenge and in 10 glioblastoma multiforme datasets. We compared its performance with four published QSM techniques and a multi-orientation QSM method. We analyzed magnetic susceptibility accuracy using brain region-of-interest measurements, and image quality using global error metrics. Reconstructions on glioblastoma data were analyzed using ranked and semiquantitative image grading by three neuroradiologist observers to assess image quality (IQ) and sharpness (IS). PnP-BM4D QSM showed good correlation (β = 0.84, R² = 0.98, p < 0.05) with COSMOS and no significant bias (bias = 0.007 ± 0.012). PnP-BM4D QSM achieved excellent quality when assessed using structural similarity index metric (SSIM = 0.860), high frequency error norm (HFEN = 58.5), cross correlation (CC = 0.804), and mutual information (MI = 0.475) and also maintained good conspicuity of fine features. In glioblastoma datasets, PnP-BM4D QSM showed higher performance (IQ_Grade = 2.4 ± 0.4, IS_Grade = 2.7 ± 0.3, IQ_Rank = 3.7 ± 0.3, IS_Rank = 3.9 ± 0.3) compared to MEDI (IQ_Grade = 2.1 ± 0.5, IS_Grade = 2.1 ± 0.6, IQ_Rank = 2.4 ± 0.6, IS_Rank = 2.9 ± 0.2) and FANSI-TGV (IQ_Grade = 2.2 ± 0.6, IS_Grade = 2.1 ± 0.6, IQ_Rank = 2.7 ± 0.3, IS_Rank = 2.2 ± 0.2). We illustrated the modularity of PnP QSM by interchanging two additional patch-based denoisers. PnP QSM reconstruction was feasible, and its flexibility was shown using several patch-based denoisers. This technique may allow rapid prototyping and validation of new denoisers for QSM reconstruction for an array of useful clinical applications.

NIMG-18. [18F]FLUCICLOVINE PET TO DISTINGUISH PSEUDOPROGRESSION FROM TUMOR PROGRESSION IN POST-TREATMENT GLIOBLASTOMA

Differentiation of true tumor progression (TP) from pseudoprogression (PsP) is a major unmet need in patients with glioblastoma. [18F]Fluciclovine is a synthetic amino acid PET radiotracer that is FDA-approved in biochemical recurrence in prostate cancer. The study aim was to assess the value of [18F]Fluciclovine PET in differentiation of histologically confirmed (“true”) TP and PsP in post-treatment of glioblastoma. METHODS: 23 patients with glioblastoma with new contrast-enhancing lesions or lesions showing increased enhancement ( &gt; 25% increase) on standard MRI after completion of radiation underwent 60-minutes dynamic [18F]Fluciclovine PET imaging. Patients subsequently underwent resection of enhancing lesion and tumor percentage vs. treatment-related changes were quantified on histopathology. Patients were considered "true” TP if tumor represented ≥ 50% of the resected specimen, mixed TP-PsP if &lt; 50% and &gt; 10%, and PsP if tumor represented ≤ 10%. Summed 30- to 40-minute post-injection PET images were used to measure SUVpeak and SUVmax (g/mL units). RESULTS: 15 patients with “true” TP, 3 with mixed TP-PsP, and 5 with PsP were included. There was a positive correlation between SUVpeak by PET and tumor percentage by histology (Rho= 0.56, p= 0.006). Patients who demonstrated “true” TP had significantly higher SUVpeak compared to patients with histological PsP (4.8±1.6 vs 2.9± 1.0, p= 0.02, AUC= 0.91, n=20). SUVpeak cut-off of 3.3 provided 93% sensitivity, 80% specificity, and 90% accuracy for differentiation of “true” TP from PsP. Patients with “true” TP/mixed TP-PsP also had significantly higher SUVpeak than patients with PsP (4.6±1.5 vs 2.9± 1.0, p= 0.03, AUC= 0.88, n=23). SUVmax and partial volume-corrected SUVpeak and SUVmax exhibited similar performance. CONCLUSION: Our results indicated that [18F]Fluciclovine PET imaging can accurately differentiate “true” TP from PsP. Further studies are required to confirm these promising early results and determine optimal criteria for interpreting [18F]Fluciclovine PET to distinguish PsP from TP.

NIMG-12. MR SUSCEPTIBILITY IMAGING FOR DETECTION OF TUMOR-ASSOCIATED MACROPHAGES IN GLIOBLASTOMA

BACKGROUND

Tumor-associated macrophages (TAMs) are a key component of glioblastoma (GBM) tumor microenvironment. Considering the differential role of different TAM phenotypes in iron metabolism with the M1 phenotype storing intracellular iron, and M2 phenotype releasing iron in the tumor microenvironment, here we investigated non-invasive quantitative susceptibility mapping (QSM) and T2* MRI relaxometry to quantify iron as imaging biomarkers for TAMs in adult patients with GBM.

METHODS

In this prospective study, 21 adult patients with GBM were enrolled between 2016 to 2019. Patients underwent a 3D single echo gradient echo sequence in addition to standard anatomical sequences on a 3 Tesla MRI. QSM images were reconstructed using the morphology-enabled dipole inversion (MEDI) algorithm. In 3 subjects, ex vivo imaging of surgical specimens was performed on a Bruker 9.4 Tesla 8.9 cm vertical bore MR using 3D multi-echo GRE scans, and R2* (1/T2*) maps were generated by a pixel-wise monoexponential fitting. Each specimen was stained with hematoxylin and eosin, as well as with CD68, CD86, CD206, and L-Ferritin.

RESULTS

Significant positive correlation was observed between mean susceptibility for the tumor enhancing zone and the L-ferritin positivity percent (r =0.56, p=0.018) and the combination of tumor’s enhancing zone and necrotic core and the L-Ferritin positivity percent (r=0.72; p=0.001). Moreover, the mean susceptibility significantly correlated with positivity percent for CD68 (ρ=0.52, p=0.034) and CD86 (r=0.7 p=0.001), but not for CD206 (ρ=0.09; p=0.7). There was a positive correlation between mean R2* values and CD68 positive cell counts (r =0.6, p=0.016). Similarly, mean R2* values significantly correlated with CD86 (r=0.54, p=0.03) but not with CD206 (r=0.15, p=0.5). High mean susceptibility in the necrotic core was associated with inferior PFS (hazard ratio,4.5, p=0.016).

CONCLUSION

MR Susceptibility Imaging can quantify the iron content of GBM and provide a non-invasive method for TAM quantification and phenotyping.

Synergistic immunotherapy of glioblastoma by dual targeting of IL-6 and CD40

Immunologically-cold tumors including glioblastoma (GBM) are refractory to checkpoint blockade therapy, largely due to extensive infiltration of immunosuppressive macrophages (Mϕs). Consistent with a pro-tumor role of IL-6 in alternative Mϕs polarization, we here show that targeting IL-6 by genetic ablation or pharmacological inhibition moderately improves T-cell infiltration into GBM and enhances mouse survival; however, IL-6 inhibition does not synergize PD-1 and CTLA-4 checkpoint blockade. Interestingly, anti-IL-6 therapy reduces CD40 expression in GBM-associated Mϕs. We identify a Stat3/HIF-1α-mediated axis, through which IL-6 executes an anti-tumor role to induce CD40 expression in Mϕs. Combination of IL-6 inhibition with CD40 stimulation reverses Mϕ-mediated tumor immunosuppression, sensitizes tumors to checkpoint blockade, and extends animal survival in two syngeneic GBM models, particularly inducing complete regression of GL261 tumors after checkpoint blockade. Thus, antibody cocktail-based immunotherapy that combines checkpoint blockade with dual-targeting of IL-6 and CD40 may offer exciting opportunities for GBM and other solid tumors.

Data-Driven Quantitative Susceptibility Mapping Using Loss Adaptive Dipole Inversion (LADI)

BACKGROUND

Quantitative susceptibility mapping (QSM) uses prior information to reconstruct maps, but prior information may not show pathology and introduce inconsistencies with susceptibility maps, degrade image quality and inadvertently smoothing image features.

PURPOSE

To develop a local field data-driven QSM reconstruction that does not depend on spatial edge prior information.

STUDY TYPE

Retrospective.

SUBJECTS, ANIMAL MODELS

A dataset from 2016 ISMRM QSM Challenge, 11 patients with glioblastoma, a patient with microbleeds and porcine heart.

SEQUENCE/FIELD STRENGTH

3D gradient echo sequence on 3T and 7T scanners.

ASSESSMENT

Accuracy was compared to Calculation of Susceptibility through Multiple Orientation Sampling (COSMOS), and several published techniques using region of interest (ROI) measurements, root-mean-squared error (RMSE), structural similarity index metric (SSIM), and high-frequency error norm (HFEN). Numerical ranking and semiquantitative image grading was performed by three expert observers to assess overall image quality (IQ) and image sharpness (IS).

STATISTICAL TESTS

Bland-Altman, Friedman test, and Conover multiple comparisons.

RESULTS

Loss adaptive dipole inversion (LADI) (β = 0.82, R² = 0.96), morphology-enabled dipole inversion (MEDI) (β = 0.91, R² = 0.97), and fast nonlinear susceptibility inversion (FANSI) (β = 0.81, R² = 0.98) had excellent correlation with COSMOS and no bias was detected (bias = 0.006 ± 0.014, P < 0.05). In glioblastoma patients, LADI showed consistently better performance (IQ_Grade = 2.6 ± 0.4, IS_Grade = 2.6 ± 0.3, IQ_Rank = 3.5 ± 0.4, IS_Rank = 3.9 ± 0.2) compared with MEDI (IQ_Grade = 2.1 ± 0.3, IS_Grade = 2 ± 0.5, IQ_Rank = 2.4 ± 0.5, IS_Rank = 2.8 ± 0.2) and FANSI (IQ_Grade = 2.2 ± 0.5, IS_Grade = 2 ± 0.4, IQ_Rank = 2.8 ± 0.3, IS_Rank = 2.1 ± 0.2). Dark artifact visible near the infarcted region in MEDI (Inf_MEDI = -0.27 ± 0.06 ppm) was better mitigated by FANSI (Inf_FANSI-TGV = -0.17 ± 0.05 ppm) and LADI (Inf_LADI = -0.18 ± 0.05 ppm).

CONCLUSION

For neuroimaging applications, LADI preserved image sharpness and fine features in glioblastoma and microbleed patients. LADI performed better at mitigating artifacts in cardiac QSM.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY STAGE: 1 J. Magn. Reson. Imaging 2020;52:823-835.

Clinical Utility of Plasma Cell-Free DNA in Adult Patients with Newly Diagnosed Glioblastoma: A Pilot Prospective Study

PURPOSE

The clinical utility of plasma cell-free DNA (cfDNA) has not been assessed prospectively in patients with glioblastoma (GBM). We aimed to determine the prognostic impact of plasma cfDNA in GBM, as well as its role as a surrogate of tumor burden and substrate for next-generation sequencing (NGS).

EXPERIMENTAL DESIGN

We conducted a prospective cohort study of 42 patients with newly diagnosed GBM. Plasma cfDNA was quantified at baseline prior to initial tumor resection and longitudinally during chemoradiotherapy. Plasma cfDNA was assessed for its association with progression-free survival (PFS) and overall survival (OS), correlated with radiographic tumor burden, and subjected to a targeted NGS panel.

RESULTS

Prior to initial surgery, GBM patients had higher plasma cfDNA concentration than age-matched healthy controls (mean 13.4 vs. 6.7 ng/mL, P < 0.001). Plasma cfDNA concentration was correlated with radiographic tumor burden on patients' first post-radiation magnetic resonance imaging scan (ρ = 0.77, P = 0.003) and tended to rise prior to or concurrently with radiographic tumor progression. Preoperative plasma cfDNA concentration above the mean (>13.4 ng/mL) was associated with inferior PFS (median 4.9 vs. 9.5 months, P = 0.038). Detection of ≥1 somatic mutation in plasma cfDNA occurred in 55% of patients and was associated with nonstatistically significant decreases in PFS (median 6.0 vs. 8.7 months, P = 0.093) and OS (median 5.5 vs. 9.2 months, P = 0.053).

CONCLUSIONS

Plasma cfDNA may be an effective prognostic tool and surrogate of tumor burden in newly diagnosed GBM. Detection of somatic alterations in plasma is feasible when samples are obtained prior to initial surgical resection.

18F-Fluciclovine PET to distinguish treatment-related effects from disease progression in recurrent glioblastoma: PET fusion with MRI guides neurosurgical sampling

Differentiation of true tumor progression from treatment-related effects remains a major unmet need in caring for patients with glioblastoma. Here, we report how the intraoperative combination of MRI with¹⁸F-fluciclovine PET guided surgical sampling in 2 patients with recurrent glioblastoma.¹⁸F-Fluciclovine PET is FDA approved for use in prostate cancer and carries an orphan drug designation in glioma. To investigate its utility in recurrent glioblastoma, we fused PET and MRI images using 2 different surgical navigation systems and performed targeted stereotactic biopsies from the areas of high (“hot”) and low (“cold”) radiotracer uptake. Concordant histopathologic and imaging findings suggest that a combined¹⁸F-fluciclovine PET-MRI–guided approach can guide neurosurgical resection of viable recurrent glioblastoma in the background of treatment-related effects, which can otherwise look similar on MRI.

Lack of choline elevation on proton magnetic resonance spectroscopy in grade I-III gliomas

Elevated levels of choline are generally emphasized as marker of increased cellularity and cell membrane turnover in gliomas. In this study, we investigated the incidence rate of lack of choline/creatine and choline/water elevation in a population of grade I-III gliomas. A cohort of 41 patients with histopathologically confirmed gliomas underwent multi-voxel proton magnetic resonance spectroscopy on a 3 T magnetic resonance system prior to treatment. Peak areas for choline and myoinositol were measured from all voxels that exhibited hyperintensity on fluid-attenuated inversion recovery images and were normalized to creatine and unsuppressed water from each voxel. The average metabolite/creatine and metabolite/water ratios from these voxels were then computed. Similarly, average metabolite ratios were computed from normal brain parenchyma. Gliomas were considered for lack of choline elevation when choline/creatine and choline/water ratios from neoplastic regions were less than those from normal brain parenchyma regions. Six of 41 (14.6%) grade I-III gliomas showed lack of elevation for choline/creatine and choline/water ratios compared to normal brain parenchyma. Four of these six gliomas also demonstrated elevated levels of myoinositol/creatine ratio. All other gliomas (n = 35) had elevated choline levels from neoplastic regions relative to normal parenchyma. The sensitivity of choline/creatine or choline/water in determining a grade I-III glioma was 85.4%. These findings suggest that a lack of choline/creatine or choline/water elevation may be seen in some gliomas and low choline levels should not prevent us from considering the possibility of a grade I-III glioma.

Metabolic Changes of Brain Developmental Venous Anomalies on 18F-FDG-PET

RATIONALE AND OBJECTIVES

To determine the metabolic effects of developmental venous anomalies (DVAs) and to correlate those effects with conventional magnetic resonance imaging (MRI) findings.

MATERIALS AND METHODS

We conducted a retrospective review of MRI and brain 18F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET) examinations in subjects with DVAs. Conventional MRI was used to determine DVA number, location, size, and associated parenchymal findings such as atrophy, hemorrhage, cavernoma, capillary telangiectasia, cortical dysplasia/polymicrogyria, and white matter signal abnormality. Qualitative and quantitative measures of relative metabolism in the drainage territory of the DVA were measured on ¹⁸F-FDG-PET.

RESULTS

Fifty-four subjects with 57 DVAs were included in the analysis. 38% were associated with qualitative and quantitative metabolic abnormalities on ¹⁸F-FDG-PET, with decreased metabolism in the parenchyma surrounding all but one of these DVAs. DVAs draining gray matter were significantly more likely to be hypometabolic than those draining only white matter, suggesting that the metabolic effects of DVAs may be underestimated on ¹⁸F-FDG-PET.

CONCLUSION

Altered metabolism is seen in the drainage territory of a significant proportion of DVAs, suggesting that these anomalies are vascular lesions with abnormal physiologic features.

Reversible Dilation of the Superior Ophthalmic Vein in Intubated Patients

BACKGROUND AND PURPOSE

Superior ophthalmic vein enlargement has typically been associated with increased intracranial or orbital pressure. This study evaluates the incidence of superior ophthalmic vein enlargement in intubated patients without pre-existing intracranial or intraorbital pathologies.

MATERIALS AND METHODS

Two cohorts (patients with trauma and epilepsy patients undergoing stereotactic intracranial lead placement) who underwent CT while intubated and shortly following extubation and a cohort of 30 outpatients with a history of headache and normal head CT findings (healthy controls) were included. The superior ophthalmic vein diameter was measured on all scans.

RESULTS

Seventy patients intubated for trauma and 45 patients with intraoperative CT were included (n = 115). While intubated, 66% of the total sample had at least unilateral superior ophthalmic vein dilation of >2.5 mm and 48% had bilateral dilation. Fifty-seven percent of patients with trauma and 84% of intraoperative patients with dilated superior ophthalmic veins showed reversal of mean superior ophthalmic vein dilation to <2.5 mm on postextubation CT. The mean superior ophthalmic vein diameter decreased an average of 1.2 mm following extubation. Changes in superior ophthalmic vein diameter between intubated and extubated states were statistically significant (P < .001). Differences between the control group and the extubated subjects were not statistically significant (P = .21).

CONCLUSIONS

Bilateral dilation of the superior ophthalmic vein is common in intubated patients and usually reverses following extubation. In the appropriate clinical setting, this knowledge will prevent misinterpretation of prominent superior ophthalmic veins as automatically indicative of an underlying pathology.

Reversible dilatation of lumbar epidural venous plexus secondary to pelvic venous compression: mimicker of pathology

Radiculopathy from dilated epidural varices is a rarely recognized phenomenon, and engorged varices may mimic a disc herniation, fistula or mass. We report a case of a distended bladder causing reversible pelvic venous congestion and resultant epidural venous plexus engorgement. We show marked engorgement of the epidural venous plexus and crowding of the cauda equina from a markedly distended bladder with resolution of these findings following bladder decompression. Familiarity with this clinical entity is crucial to avoid misdiagnosis and to prevent potential unnecessary surgical intervention.

Correlating Cognitive Decline with White Matter Lesion and Brain Atrophy Magnetic Resonance Imaging Measurements in Alzheimer's Disease

BACKGROUND

Vascular risk factors are increasingly recognized as risks factors for Alzheimer's disease (AD) and early conversion from mild cognitive impairment (MCI) to dementia. While neuroimaging research in AD has focused on brain atrophy, metabolic function, or amyloid deposition, little attention has been paid to the effect of cerebrovascular disease to cognitive decline.

OBJECTIVE

To investigate the correlation of brain atrophy and white matter lesions with cognitive decline in AD, MCI, and control subjects.

METHODS

Patients with AD and MCI, and healthy subjects were included in this study. Subjects had a baseline MRI scan, and baseline and follow-up neuropsychological battery (CERAD). Regional volumes were measured, and white matter lesion segmentation was performed. Correlations between rate of CERAD score decline and white matter lesion load and brain structure volume were evaluated. In addition, voxel-based correlations between baseline CERAD scores and atrophy and white matter lesion measures were computed.

RESULTS

CERAD rate of decline was most significantly associated with lesion loads located in the fornices. Several temporal lobe ROI volumes were significantly associated with CERAD decline. Voxel-based analysis demonstrated strong correlation between baseline CERAD scores and atrophy measures in the anterior temporal lobes. Correlation of baseline CERAD scores with white matter lesion volumes achieved significance in multilobar subcortical white matter.

CONCLUSION

Both baseline and declines in CERAD scores correlate with white matter lesion load and gray matter atrophy. Results of this study highlight the dominant effect of volume loss, and underscore the importance of small vessel disease as a contributor to cognitive decline in the elderly.

Intracranial aneurysms in sickle cell anemia: clinical and imaging findings

BACKGROUND

Cerebral aneurysm formation is one of the cerebrovascular complications of sickle cell disease.

OBJECTIVE

To report the clinical and imaging findings of intracerebral aneurysms and their treatment in pediatric and adult patients with sickle cell disease.

METHODS

Review of clinical data via chart abstraction and radiologic features at the University of Pennsylvania and Children's Hospital of Philadelphia from 2000 to 2014 and review of the literature since 1942.

RESULTS

Nineteen patients with aneurysms (2.7%) were found in 709 imaged patients, including 1.2% of imaged children and 10.8% of adults. A total of 44 aneurysms were detected (52.6% with multiple aneurysms, overall 2.3 per patient), 35 (79.5%) in the anterior circulation and 9 in the posterior circulation (20.4%). Thirty-eight unruptured aneurysms ranging in size from 2 to 6 mm and six ruptured aneurysms ranging in size from 3 to 9 mm in diameter were found. Of the patients with ruptured aneurysms, two were treated by stent-assisted coiling, two by clipping, and one patient with coiling. In the group without a rupture, one patient was treated by coil embolization and one patient with a peripheral middle cerebral artery aneurysm was treated by aneurysmectomy. Three pediatric patients with a previously normal MR angiogram demonstrated new aneurysm formation during the study.

CONCLUSIONS

Adult patients with sickle cell disease have a high prevalence of aneurysm formation. Both pediatric and adult patients with sickle cell disease tend to develop multiple aneurysms with frequent involvement of atypical locations, in both anterior and posterior circulations.

Correlation of prenatal and postnatal MRI findings in schizencephaly

BACKGROUND AND PURPOSE

Schizencephaly is a rare malformation of the brain characterized by a gray matter-lined defect extending from the pial surface to the lateral ventricles. The purpose of this study was to correlate imaging findings of schizencephaly and associated anomalies on fetal and postnatal MR imaging and assess possible changes that may occur from the prenatal-to-postnatal state.

MATERIALS AND METHODS

A retrospective review of subjects with schizencephaly who had both pre- and postnatal MR imaging was performed. Subject age, cleft type, number, location, and features of the defects and associated anomalies were recorded. Normalized dimensions of the defect and ipsilateral ventricle were measured and correlated to changes in the clefts between pre- and postnatal imaging.

RESULTS

Ten subjects with 18 clefts (8 bilateral) were included. Most defects (83%) were open on prenatal MR imaging, but 47% of those were found to have subsequently closed on postnatal imaging. Evidence of prior hemorrhage was seen in 83%. Prenatal MR imaging detected all cases of an absent septum pellucidum but detected a fraction of gross polymicrogyria and missed all cases of optic nerve hypoplasia. The normalized ipsilateral ventricular and inner and middle width dimensions of the defects were significantly decreased at postnatal imaging (P < .05). The widths of the defects, ventricular width, and presence of hemorrhage were not predictors of closure of prenatally diagnosed open defects (P > .05).

CONCLUSIONS

In our series, nearly half of prenatally open schizencephaly defects had closed on postnatal imaging. Prenatal MR imaging was only able to demonstrate some of the associated anomalies.

CT and MRI of pediatric skull lesions with fluid-fluid levels

Fluid-fluid levels can occur whenever different fluid densities are contained within a cystic or compartmentalized lesion, usually related to the evolution of hematoma or necrosis. Review of the literature demonstrated that throughout the skeletal system, the most common etiology for fluid-fluid levels is aneurysmal bone cyst, but there are no dedicated studies of the pediatric calvaria, to our knowledge. In this report, we present clinicopathologic characteristics and CT and MR imaging of 11 patients with pediatric skull mass lesions demonstrating fluid-fluid levels. MR imaging demonstrated more fluid-fluid levels compared with CT in all cases. The etiologies of skull lesions with fluid-fluid levels were Langerhans cell histiocytosis in 4 (36.6%), aneurysmal bone cysts in 3 (27.2%), cephalohematoma in 3 (27.2%), and metastatic neuroblastoma in 1 (9%). Radiologists should be aware of the other etiologies of calvarial lesions with fluid-fluid levels in the pediatric skull.

Retroesophageal aortic arch in a patient with pulmonary embolism

The authors report an interesting case of right retroesophageal aortic arch (REAA) with pulmonary embolism that presented like the dissection of the aortic aneurysm but eventually diagnosed by means of spiral CT. Right REAA should be considered as a rare cause of mediastinal widening in the patients in whom significant difference between the blood pressure and pulse intensity of both extremities is evident to prevent the erroneous diagnosis and treatment.

Foley catheter entrapment resulting from the formation of a true knot in a female infant: sonographic findings

One of the rarest complications of bladder Foley catheter insertion is knotting of the catheter. We present a case of Foley entrapment secondary to formation of a true knot at the proximal end of the catheter in a 6-month-old female infant who was referred to our center for voiding cystourethrograthy. Sonography of the bladder revealed the knotted catheter in the urinary bladder.

Percutaneous transhepatic venous angioplasty and stenting in a 9-month-old patient with hepatic vein obstruction after partial liver transplantation

Hepatic venous outflow obstruction is a rare but serious complication after liver transplantation. We report ultrasound-guided percutaneous transhepatic stent placement in a 9-month-old infant with a left lateral split liver transplantation with near-complete hepatic vein obstruction.

Methanol poisoning: acute MR and CT findings in nine patients

INTRODUCTION

Methanol poisoning is an uncommon but potent central nervous system toxin. We describe here the CT and MR findings in nine patients following an outbreak of methanol poisoning.

METHODS

Five patients with a typical clinical presentation and elevated anion and osmolar gaps underwent conventional brain MRI with a 1.5-T Gyroscan Interna scanner. In addition nonenhanced CT was performed in another three patients with more severe toxicity.

RESULTS

Bilateral hemorrhagic or nonhemorrhagic necrosis of the putamina, diffuse white matter necrosis, and subarachnoid hemorrhage were among the radiological findings. Various patterns of enhancement of basal ganglial lesions were found including no enhancement, strong enhancement and rim enhancement.

CONCLUSION

A good knowledge of the radiological findings in methanol poisoning seems to be necessary for radiologists. The present study is unique in that it enables us to include in a single report most of the radiological findings that have been reported previously.

Anthrax: pathological aspects in autopsy cases in Shiraz, Islamic Republic of Iran, 1960-2001

Anthrax, like tuberculosis, shows a new epidemic spread in industrialized countries, revealing some ambiguous aspects to the disease and providing new challenges to medicine. Shiraz University of Medical Sciences has records of 7130 autopsies performed in the past 40 years, 33 of which are anthrax cases. We reviewed all the pathology slides of these cases and classified the organs involved in a search for unrecognized microscopic findings. The most common cause of death was sepsis, caused by organ involvement and direct cytotoxicity of Bacillus anthracis, in addition to its exotoxin production. Novel findings included hyaline membrane formation in respiratory system cases that is similar to acute (adult) respiratory distress syndrome and evidence of primary gastrointestinal involvement, showing the ability of the organism to pass the gastric barrier.