An Automated Brain Metastasis Detection and Segmentation System from MRI with a Large Multi-Institutional Dataset

PURPOSE/OBJECTIVE(S)

Developments of automated systems for brain metastasis (BM) detection and segmentation from MRI for assisting early detection and stereotactic radiosurgery (SRS) have been reported but most based upon relatively small datasets from single institutes. This work aims to develop and evaluate a system using a large multi-institutional dataset, and to improve both identification of small/subtle BMs and segmentation accuracy of large BMs.

MATERIALS/METHODS

A 3D U-Net system was trained and evaluated to detect and segment intraparenchymal BMs with a size > 2mm using 1856 MRI volumes from 1791 patients treated with SRS from seven institutions (1539 volumes for training, 183 for validation, and 134 for testing). All patients had 3D post-Gd T1w MRI scans pre-SRS. Gross tumor volumes (GTVs) of BMs for SRS were curated by each institute first. Then, additional efforts were spent to create GTVs for the untreated and/or uncontoured BMs, including central reviews by two radiologists, to improve accuracy of ground truth. The training dataset was augmented with synthetic BMs of 3773 MRIs using a 3D generative pipeline. Our system consists of two U-Nets with one using small 3D patches dedicated for detecting small BMs and another using large 3D patches for segmenting large BMs, and a random-forest based fusion module for combining the two network outputs. The first U-Net was trained with 3D patches containing at least one BM < 0.1 cm3. For detection performance, we measured BM-level sensitivity and case-level false-positive (FP) rate. For segmentation performance, we measured BM-level Dice similarity coefficient (DSC) and 95-percentile Hausdorff distance (HD95). We also stratified performances based upon BM sizes.

RESULTS

For 739 BMs in the 134 testing cases, the overall lesion-level sensitivity was 0.870 with an average case-level FP of 1.34±1.92 (95% CI: 1.02-1.67). The sensitivity was >0.969 for the BMs >0.1 cm3, but dropped to 0.755 for the BMs < 0.1 cm3 (Table 1). The average DSC and HD95 for all detected BMs were 0.786 and 1.35mm. The worse performance for BMs > 20 cm3 was caused by a case with 83 cm3 GTV and artifacts in the MRI volume.

CONCLUSION

We achieved excellent detection sensitivity and segmentation accuracy for BMs > 0.1 cm3, and promising performance for small BMs (<0.1cm3) with a controlled FP rate using a large multi-institutional dataset. Clinical utility for assisting early detection and SRS planning will be investigated. Table 1: Per-lesion detection and segmentation performance stratified by individual BM size. N is the number of BMs in each category.

RT-PCR negative COVID-19

Background

COVID-19 is a multi-system infection with emerging evidence-based antiviral and anti-inflammatory therapies to improve disease prognosis. However, a subset of patients with COVID-19 signs and symptoms have repeatedly negative RT-PCR tests, leading to treatment hesitancy. We used comparative serology early in the COVID-19 pandemic when background seroprevalence was low to estimate the likelihood of COVID-19 infection among RT-PCR negative patients with clinical signs and/or symptoms compatible with COVID-19.

Methods

Between April and October 2020, we conducted serologic testing of patients with (i) signs and symptoms of COVID-19 who were repeatedly negative by RT-PCR (‘Probables’; N = 20), (ii) signs and symptoms of COVID-19 but with a potential alternative diagnosis (‘Suspects’; N = 15), (iii) no signs and symptoms of COVID-19 (‘Non-suspects’; N = 43), (iv) RT-PCR confirmed COVID-19 patients (N = 40), and (v) pre-pandemic samples (N = 55).

Results

Probables had similar seropositivity and levels of IgG and IgM antibodies as propensity-score matched RT-PCR confirmed COVID-19 patients (60.0% vs 80.0% for IgG, p-value = 0.13; 50.0% vs 72.5% for IgM, p-value = 0.10), but multi-fold higher seropositivity rates than Suspects and matched Non-suspects (60.0% vs 13.3% and 11.6% for IgG; 50.0% vs 0% and 4.7% for IgM respectively; p-values < 0.01). However, Probables were half as likely to receive COVID-19 treatment than the RT-PCR confirmed COVID-19 patients with similar disease severity.

Conclusions

Findings from this study indicate a high likelihood of acute COVID-19 among RT-PCR negative with typical signs/symptoms, but a common omission of COVID-19 therapies among these patients. Clinically diagnosed COVID-19, independent of RT-PCR positivity, thus has a potential vital role in guiding treatment decisions.

Highly versatile antibody binding assay for the detection of SARS-CoV-2 infection and vaccination

Monitoring the burden and spread of infection with the new coronavirus SARS-CoV-2, whether within small communities or in large geographical settings, is of paramount importance for public health purposes. Serology, which detects the host antibody response to the infection, is the most appropriate tool for this task, since virus-derived markers are most reliably detected during the acute phase of infection. Here we show that our ELISA protocol, which is based on antibody binding to the Receptor Binding Domain (RBD) of the S1 subunit of the viral Spike protein expressed as a novel fusion protein, detects antibody responses to SARS-CoV-2 infection and vaccination. We also show that our ELISA is accurate and versatile. It compares favorably with commercial assays widely used in clinical practice to determine exposure to SARS-CoV-2. Moreover, our protocol accommodates use of various blood- and non-blood-derived biospecimens, such as breast milk, as well as dried blood obtained with microsampling cartridges that are appropriate for remote collection. As a result, our RBD-based ELISA protocols are well suited for seroepidemiology and other large-scale studies requiring parsimonious sample collection outside of healthcare settings.

Highly versatile antibody binding assay for the detection of SARS-CoV-2 infection

Monitoring the burden and spread of infection with the new coronavirus SARS-CoV-2, whether within small communities or in large geographical settings, is of paramount importance for public health purposes. Serology, which detects the host antibody response to the infection, is the most appropriate tool for this task, since virus-derived markers are most reliably detected during the acute phase of infection. Here we show that our ELISA protocol, which is based on antibody binding to the Receptor Binding Domain (RBD) of the S1 subunit of the viral Spike protein expressed as a novel fusion protein, detects antibody responses to SARS-CoV-2 infection and COVID-19 vaccination.

We also show that our ELISA is accurate and versatile. It compares favorably with commercial assays widely used in clinical practice to determine exposure to SARS-CoV-2. Moreover, our protocol accommodates use of various blood- and non-blood-derived biospecimens, such as breast milk, as well as dried blood obtained with microsampling cartridges that are appropriate for remote collection. As a result, our RBD-based ELISA protocols are well suited for seroepidemiology and other large-scale studies requiring parsimonious sample collection outside of healthcare settings.

Analytical performance of the Xpert MTB/XDR® assay for tuberculosis and expanded resistance detection

In a manufacturer-independent laboratory validation study, the Xpert MTB/XDR® assay demonstrated equivalent limit of detection to Xpert MTB/RIF®, detected 100% of tested resistance mutations and showed some utility for resistance detection in strain mixtures. The Xpert MTB/XDR assay is a reliable, sensitive assay for tuberculosis and expanded resistance detection.

A Pilot Study of Human Papillomavirus Detection in Urine Using a Novel Nucleic Acid Amplification Test

INTRODUCTION

Human papillomavirus (HPV) testing is the standard-of-care for cervical cancer screening globally. Urine is a promising alternative to collecting a cervical specimen during a pelvic exam for HPV testing. There are no studies to date of HPV testing of urine using the Xpert HPV test.

METHODS

We conducted a pilot study of 40 women; 30 women undergoing colposcopy because of a previous abnormality and 10 undergoing routine screening, to evaluate HPV detection in urine by the Xpert HPV test on the GeneXpert platform. Xpert HPV testing of urine was done according to the manufacturer's instructions for testing cervical specimens. These results were compared to a reference of combined results of 2 research HPV genotyping tests conducted on cervical specimens and to repeat Xpert HPV testing of urine.

RESULTS

Analytic sensitivity and specificity of Xpert testing of urine for any high-risk HPV versus the cervical sample, categorized as HPV positive if at least 1 test was positive, were 64.3% (95% confidence interval [95%CI]  = 42.1-76.1%) and 100% (97.5%CI = 71.5-100%), respectively. Analytic sensitivity and specificity of Xpert testing of urine for any high-risk HPV versus the cervical sample, categorized as positive if both tests were positive, were 66.7% (95%CI = 44.7-84.4%) and 86.7% (95%CI = 59.5-98.3%), respectively. Kappa values for first vs. second and first vs. third testing of urine by Xpert were 0.89 (95%CI = 0.79-1.00) and 0.90 (95%CI = 0.81-1.00), respectively.

DISCUSSION

Given the call for global elimination of cervical cancer and widespread availability of GeneXpert, optimizing Xpert HPV testing of urine may be warranted.

Mechanochemical synthesis of high coercivity Nd2(Fe,Co)14B magnetic particles

With increasing demand for magnets in energy conversion systems, the quest for the development and understanding of novel processing routes to produce permanent magnets has become urgent. We report a novel mechanochemical process for the synthesis of Nd₂(Fe,Co)₁₄B magnetic particles with a high coercivity of 12.4 kOe. This process involves the reduction of neodymium oxide, iron oxide, cobalt oxide and boron anhydride in the presence of a calcium reducing agent and a CaO diluent. The formation mechanism of Nd₂(Fe,Co)₁₄B changed with increasing CaO content, and the average crystal size of the Nd₂(Fe,Co)₁₄B particles also increased, resulting in an increase in the coercivity values. The reaction mechanism during milling was revealed through a study of the phase transformations as a function of milling time. It was found that unlike self-propagating reactions, this reduction reaction during milling requires continuous input of mechanical energy to reach a steady state.

Posterior Fossa Hypervascular Tumour Embolisation

Hemangioblastomas are histologically benign tumours that comprise 7–12% of all posterior fossa lesions. Treatment of these lesions is often complicated by the significant vascularity of the tumour and the difficult surgical resection in the sensitive neural tissue. In such situations, preoperative embolisation facilitates surgery by not only decreasing the intraoperative blood loss, but also by decreasing the total operative time and allowing a near complete resection of the tumour. Though infrequent, fatal complications can occur during preoperative embolisation procedures. We report two such cases in which the tumour bled during the procedure. In both cases, this was effectively managed by arterial pedicle occlusion with NBCA (N-Butyl Cyano acrylate). The early detection, immediate control and the possible causes of this complication is presented.

Clinical significance of small airway obstruction markers in patients with asthma

BACKGROUND

The role of small airway obstruction in the clinical expression of asthma is incompletely understood.

OBJECTIVE

We tested the hypotheses that markers of small airway obstruction are associated with (i) increased asthma severity, (ii) impaired asthma control and quality of life and (iii) frequent exacerbations.

METHODS

Seventy-four adults with asthma and 18 healthy control subjects underwent impulse oscillometry (IOS), multiple breath inert gas washout (MBW), body plethysmography, single-breath determination of carbon monoxide uptake and spirometry. Patients completed the six-point Asthma Control Questionnaire (ACQ-6) and standardized Asthma Quality of Life Questionnaire [AQLQ(S)]. Asthma severity was classified according to the Global Initiative for Asthma (GINA) treatment steps.

RESULTS

The putative small airway obstruction markers Sacin , resistance at 5 Hz minus resistance at 20 Hz (R5-R20) and reactance area (AX) were not independently associated with asthma severity, control, quality of life or exacerbations. In contrast, markers of total (R5) and mean airway resistance of large and small airways (R20) were significantly higher in the severe asthma group compared with the mild-moderate group (0.47 vs. 0.37, P < 0.05 for R5; 0.39 vs. 0.31, P < 0.01 for R20). The strongest independent contributors to ACQ-6 score were R20 and forced expiratory volume in one second (% pred.), and the strongest independent contributors to AQLQ(S) score were R20 and forced vital capacity (% pred.). A history of one or more exacerbations within the previous year was independently associated with R20.

CONCLUSIONS AND CLINICAL RELEVANCE

Previously reported markers of small airway obstruction do not appear to be independently associated with asthma disease expression. In contrast, the IOS parameter R20, a marker of mean airway resistance of both large and small airways, appears to have independent clinical significance. These observations require confirmation in prospective longitudinal studies.

Raise the bar and lower the dose: current and future strategies for radiation dose reduction in head and neck imaging

SUMMARY

Technologic advances in CT have generated a dramatic increase in the number of CT studies, with a resultant increase in the radiation dose related to CT scanning. Such increase in radiation dose is becoming a concern for the radiology community, especially with increasing public awareness of the dose burden related to examinations. To cope with the increase in CT-related radiation exposure, it is becoming necessary to optimize CT imaging protocols and apply radiation dose reduction techniques to ensure the best imaging with the lowest radiation dose.

Abstract PD1-3: Ph1b study of the PI3K inhibitor GDC-0032 in combination with fulvestrant in patients with hormone receptor-positive advanced breast cancer

Background: GDC-0032 is a next-generation PI3K inhibitor with increased anti-tumor activity against PIK3CA mutant cancers. GDC-0032 is an orally bioavailable, potent, and selective inhibitor of Class I PI3K alpha, delta, and gamma isoforms, with 30-fold less inhibition of the PI3K beta isoform relative to the PI3K alpha isoform. Preclinical data show that GDC-0032 has enhanced activity against PI3K alpha isoform (PIK3CA) mutant breast cancer cell lines. Preclinical data also show enhanced antitumor activity when GDC-0032 is combined with fulvestrant.

Material and Methods: A Phase 1b dose escalation study was conducted with evaluation of GDC-0032 doses ranging from 6-9 mg QD in combination with fulvestrant 500mg q4wk (with loading dose of 500mg at day 1, 14 and 28) in a modified 3+3 design. A dose expansion cohort was conducted at the recommended Phase 2 dose of 6 mg QD. Safety and tolerability of GDC-0032 was assessed, as well as pharmacokinetics (PK), pharmacodynamic (PD) assessment of PI3K pathway inhibition by paired tumor biopsies and by FDG-PET, and anti-tumor activity by RECIST.

Results: As of 1 Mar 2013, 17 patients were enrolled onto this study with the completion of dose escalation. No dose limiting toxicities (DLTs) were observed at either the 6 mg or 9 mg dose levels. Adverse events (AEs) assessed by the investigator as related to GDC-0032 in ≥10% of patients, were diarrhea, hyperglycemia, stomatitis, fatigue, asthenia, decreased appetite, nausea, mucosal inflammation and rash. No observed apparent PK interactions were observed between GDC-0032 and fulvestrant. The median number of prior systemic therapies was 6. Metabolic partial responses via FDG-PET (≥ 20% decrease in mSUVmax) were observed in 8 out of 11 patients assessed (73%). Confirmed partial responses by RECIST have been observed at both the 6mg and 9mg GDC-0032 dose levels. These include patients who have had prior treatment with fulvestrant. As of 29 May 2013, enrollment onto the dose escalation and expansion cohort has been completed (n = 27). Updated data on safety, pharmacodynamics, efficacy, and biomarker correlates will be presented.

Conclusions: The combination of GDC-0032 and fulvestrant is a well-tolerated regimen with promising preliminary efficacy. GDC-0032 is being further investigated in combination with fulvestrant for patients with hormone receptor-positive advanced breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD1-3.

OCEANS: A randomized, double-blinded, placebo-controlled phase III trial of chemotherapy with or without bevacizumab (BEV) in patients with platinum-sensitive recurrent epithelial ovarian (EOC), primary peritoneal (PPC), or fallopian tube cancer (FTC)

LBA5007

Background: BEV, a humanized anti-VEGF monoclonal antibody, has shown a progression-free survival (PFS) benefit in 2 frontline phase III trials in patients with EOC, PPC and FTC. The therapeutic impact of BEV in combination with carboplatin (C) and gemcitabine (G) followed by single agent BEV to disease progression (PD) was evaluated in this phase III trial in the platinum-sensitive recurrent setting. Methods: Patients had recurrent, platinum-sensitive EOC, PPC or FTC, 1 prior regimen, no prior BEV, ECOG performance status 0-1, measurable disease. Subjects were randomized to: Arm A: [IV C (AUC 4, Day (D) 1) + G (1,000 mg/m2 D1 and 8) + placebo (PL) D1] q21D x 6 cycles (c) → PL q21D until PD or unacceptable toxicity (tox) Arm B: [CG + BEV (15 mg/kg) D1] q21D x 6 c → BEV q21D until PD or tox primary endpoint was investigator assessed PFS (RECIST). Secondary endpoints included objective response (OR), overall survival (OS), duration of response and safety. The design provided 80% power to detect a 27% reduction in the hazard of progression or death in Arm B vs A, limiting the overall type I error of 5%. Results: OCEANS enrolled 484 patients (242 per arm) from 4/07 - 1/10, median follow up of 24 months. BEV plus CG followed by single agent BEV to PD significantly increased PFS compared to CG alone (HR=0.484, p<0.0001). OR increased by 21% (p<0.0001). OS data is immature with only 29% of patients having had an event. The safety profile was consistent with other BEV trials. Conclusions: Results show a statistically significant and clinically relevant benefit when bevacizumab is added to chemotherapy in patients with recurrent, platinum sensitive EOC, PPC, and FTC. This is the first phase III trial of an antiangiogenic to demonstrate a clinical benefit to these patients.

[Table: see text]

SABRE-B: an evaluation of paclitaxel and bevacizumab with or without sunitinib as first-line treatment of metastatic breast cancer

BACKGROUND

The vascular endothelial growth factor (VEGF) pathway can be targeted through VEGF neutralization or VEGF receptor (VEGFR) blockade using tyrosine kinase inhibition. Because laboratory models suggest that combining these approaches might be synergistic, we sought to evaluate the feasibility and efficacy of combining sunitinib with paclitaxel + bevacizumab (PB).

METHODS

Patients with human epidermal growth factor receptor 2 (HER2)-negative, metastatic breast cancer receiving first-line chemotherapy were randomized to PB or PB with sunitinib (PBS), with planned escalation of the sunitinib dose.

RESULTS

Forty-six patients were randomized to PB or PBS with sunitinib dosed at 25 mg p.o. daily. Patients receiving PBS encountered substantial toxicity that precluded adequate treatment. The percentage of patients with grade ≥3 adverse events was greater in the PBS arm than the PB arm (83% versus 57%), and sunitinib dosing was modified in 78% of patients, most often due to neutropenia, febrile neutropenia, and fatigue. In addition, 44% of patients had sunitinib dose reduction to 12.5 mg, and 39% required discontinuation. Patients receiving PBS had more bevacizumab treatment interruptions and discontinuations because of toxicity. Median treatment duration was longer in the PB arm compared with the PBS arm (14.1 versus 11.1 weeks), reflecting early treatment discontinuation of PBS. Because of poor tolerability of the addition of sunitinib to PB, the planned sunitinib dose escalation was halted and the study accrual was terminated.

CONCLUSION

Adding sunitinib to standard doses of bevacizumab plus paclitaxel for metastatic breast cancer is not feasible. Different strategies will be required to evaluate whether there is additional clinical benefit to combining VEGF/VEGFR-targeted agents.

Intraosseous haemangioma of the proximal femur: imaging findings

Haemangiomas of bone are uncommon lesions, accounting for approximately 1% of all primary bone tumours. The most frequent sites of involvement are the calvaria and the vertebral column. When haemangiomas involve long tubular bones, they are usually found in the diaphysis or metadiaphysis. Juxta-articular or epiphyseal location for a long bone haemangioma is rare. We present the imaging findings in a case of a histopathologically proven juxta-articular intraosseous haemangioma of the proximal femur. We believe ours is the first report of a haemangioma involving the proximal end of the femur.

Early experiences with diffusion tensor imaging and magnetic resonance tractography in stroke patients

INTRODUCTION

Recent advances in magnetic resonance (MR) diffusion tensor imaging technique enable evaluation of the anisotropy of white matter tracts in-vivo, as well as the integrity of fibre tracts and their orientation. We describe our initial experiences with diffusion tensor imaging and MR tractography techniques to evaluate the structural degeneration of white matter tracts following stroke.

METHODS

Diffusion tensor imaging data were acquired in 11 cases with stroke on a 3T MR imaging scanner, with three-dimensional diffusion tensor imaging-based colour maps and MR tractography performed offline. We evaluated the spatial relationships of the eloquent white matter tracts to the infarcts and areas of haemorrhage, and classified therewith the tracts as either disrupted or displaced. We compared these with the clinical severity of the neurological deficits and prognosis.

RESULTS

A good correlation was found between tractography findings and patient's clinical recovery. All the patients with disruption of white matter tracts had residual deficits on clinical follow-up, whereas the patients with displaced tracts had near complete neurological recovery.

CONCLUSION

Diffusion tensor imaging and MR tractography provide a novel and useful method to directly visualise changes in the white matter tracts in stroke. This can potentially allow clinical-imaging correlation with prognostic potential.

Normal variants of the intracranial circulation demonstrated by MR angiography at 3T

Magnetic resonance angiography (MRA) at 3T offers increased signal to noise ratio with better background suppression, leading to exquisite depiction of the intracranial circulation. We present a pictorial review of the normal variations and anomalies of the intracranial circulation detected on MRA performed on a high field 3T clinical scanner using parallel imaging techniques. The salient imaging features of these anomalies and normal variations are discussed with relevance to clinical practice.

Female genital tuberculosis: hysterosalpingographic appearances

Genital tuberculosis is an important cause of infertility in developing countries and hysterosalpingography (HSG) is the initial procedure performed for the evaluation. Reviewing 37 cases of female genital tuberculosis, we encountered various appearances on HSG. Of 579 HSGs performed over a period of 4 years, 492 (85%) were performed as part of infertility work up. Genital tuberculosis was found in 6.3% of all the patients who underwent HSGs and 7.5% of all patients investigated for infertility. The various features of proven tuberculosis cases are illustrated in this pictorial review. We briefly discuss the pathology and these appearances along with radiopathological correlation.

Magnetic resonance arthrography in recurrent anterior shoulder instability as compared to arthroscopy: a prospective comparative study

AIM

To evaluate the accuracy of magnetic resonance (MR) arthrographic imaging in the diagnosis of glenoid labral and ligament tears in recurrent shoulder instability.

SETTINGS AND DESIGN

Prospective, comparative study at a tertiary care centre.

MATERIAL AND METHODS

Patients with three or more episodes of anterior shoulder dislocation were enrolled in the study. They were subjected to magnetic resonance arthrography (MRA) for delineation of abnormalities. The findings obtained at MRA were compared with those found at arthroscopy and surgical exploration.

RESULTS

MRA detected glenoid tears in all 22 patients with 20 (90%) patients having antero-inferior tears, 3 (14%) patients had superior labral involvement and 2 (10%) patients had posterior labral abnormality. On arthroscopy, antero-inferior, superior and posterior labral tear were found in 21 (95%), 5 (22%) and 7 (32%) patients respectively. MRA showed a sensitivity of 95%, and a specificity of 100% for the detection of the antero-inferior labral tears. The sensitivity of MRA for the detection of superior, middle and inferior glenohumeral ligament tear was 83%, 80% and 86% with a specificity of 100%, 71% and 93% respectively. MRA was 100% sensitive for the detection of rotator cuff injuries and detection of bony lesions like Hill-Sach's and bony Bankart's lesion.

CONCLUSIONS

MRA is a sensitive and specific modality for evaluation of anterior shoulder instability.

Subcutaneous rupture of hepatic hydatid cyst

Hepatic hydatid cysts are common entities. We present an unusual case of a hepatic hydatid cyst which had ruptured into the subcutaneous tissues of the anterior abdominal wall. The possible causes, imaging features and recent literature are reviewed.

MR imaging in intramedullary cysticercosis

Although intramedullary spinal cord cysticercosis (IMC) is uncommon, its presence is being increasingly recognised by magnetic resonance imaging. We studied six patients from an endemic region and present the MRI features and clinical correlation of IMC. Six patients who presented with para- or quadriplegia were studied by contrast enhanced spinal MRI. Prompted by the spinal lesions, all patients underwent brain MRI. Clinical data and laboratory studies were reviewed in all patients. Definite diagnosis was established in the form of response to drug therapy (n = 4) and histopathology (n = 2). Follow-up MRI studies of spine and brain were obtained in four patients 2 months after they started medical treatment, regardless of surgery. Five patients showed fusiform and focal enlargement of the spinal cord (cervical 2, thoracic 3). Well-defined cysts with a slightly hyperintense mural nodule were identified in five patients in Ti-weighted images (T1WI). All cysts were hyperintense on T2WI and merged with the surrounding oedema. Oedema extended one to three vertebral levels above or below the cyst. Post-contrast T1WI showed well-defined, ring enhancing lesions with smooth walls in all patients. Symptoms in all patients correlated with the level of the lesions. Brain studies demonstrated lesions in just two patients. Histopathological confirmation was obtained in two patients. Follow-up spinal MRI was normal in two patients, following 2 months of treatment while residual and smaller lesions were seen in two patients. Two patients were asymptomatic and denied follow-up MRI. MRI of spinal cysticercosis were typical of and similar to those seen in cerebral lesions in our patients and corresponded to the level of symptoms. All cysts were surrounded by oedema. Two of four patients showed residual lesions after 2 months of therapy and 33 % of patients showed concomitant intracranial lesions.

An enhancer sequence directs LacZ expression to developing pharyngeal endoderm in transgenic mice

The murine Hoxc-6 homeobox gene comprises three exons with two distinct promoters (PRI and PRII) located 9 kb apart. To characterise the PRII promoter, a region 3 kb upstream of the transcription start site was sequenced, and an Antananapedia-like consensus binding sequence was found (Coletta et al., 1991). A LacZ reporter gene construct, containing three copies of this sequence, directs highly specific expression in cells forming pharyngeal endoderm in transgenic mice. Expression was first detected in a few individual anterior endoderm cells at E7.5, which increase in number up to E9.5, where expression was clearly visible in the pharyngeal endoderm. Expression of the endodermal genes HNF3beta, Pax-9, Shh, and Nkx2.5 showed colocalization with the LacZ-positive cells in the foregut and pharyngeal endoderm. This novel enhancer provides a means of tracking the morphogenetic movement of endodermal cells fated to form the foregut.

Isolated symmetrical mediastinal lipomatosis

Symmetrical mediatinal lipomatosis is a rare benign condition characterized by deposition of a large amount of mature adipose tissue within the mediastinum. Usually secondary to exogenous obesity, administration of steroids and Cushing's disease, it is more common in middle-aged males and is associated with alcohol abuse. Various other associations have been reported. CT and MRI can decisively diagnose this benign condition, which also helps in deciding treatment options. We present a case of a young female with a bizarre appearance on chest radiographs. Isolated, bilaterally symmetrical mediastinal lipomatosis was diagnosed on CT and MRI. The patient was thin and did not consume alcohol or steroids. Cushing's disease and other known associations were excluded.

Intrasacral meningocele with tethered cord syndrome

We present a 65 year old, relatively asymptomatic man, who was found to have an intrasacral meningocele with tethered cord syndrome on Magnetic Resonance Imaging (MRI). Incidental detection of this entity at such an old age is very unusual.

Cytoskeletal microdifferentiation: a mechanism for organizing morphological plasticity in dendrites

Experimental evidence suggests that microfilaments and microtubules play contrasting roles in regulating the balance between motility and stability in neuronal structures. Actin-containing microfilaments are associated with structural plasticity, both during development when their dynamic activity drives the exploratory activity of growth cones and after circuit formation when the actin-rich dendritic spines of excitatory synapses retain a capacity for rapid changes in morphology. By contrast, microtubules predominate in axonal and dendritic processes, which appear to be morphologically relatively more stable. To compare the cytoplasmic distributions and dynamics of microfilaments and microtubules we made time-lapse recordings of actin or the microtubule-associated protein 2 tagged with green fluorescent protein in neurons growing in dispersed culture or in tissue slices from transgenic mice. The results complement existing evidence indicating that the high concentrations of actin present in dendritic spines is a specialization for morphological plasticity. By contrast, microtubule-associated protein 2 is limited to the shafts of dendrites where time-lapse recordings show little evidence for dynamic activity. A parallel exists between the partitioning of microfilaments and microtubules in motile and stable domains of growing processes during development and between dendrite shafts and spines at excitatory synapses in established neuronal circuits. These data thus suggest a mechanism, conserved through development and adulthood, in which the differential dynamics of actin and microtubules determine the plasticity of neuronal structures.

Arachnoiditis associated with arachnoid cyst formation and cord tethering following myelography: magnetic resonance features

The reported incidence of clinically significant arachnoiditis following oil-based contrast media myelography is approximately 1%. The incidence of arachnoiditis in the dorsal spine is even more rare. Acquired arachnoid cyst formation can occur with arachnoiditis of various aetiologies. A case is presented of a patient with chronic backache, radiculopathy, weakness and muscle wasting, who had undergone myelography with oil-based contrast media about 28 years ago. There was no history of spinal surgery, spinal canal stenosis, disc disease or trauma, all of which are known to increase the risk of arachnoiditis. Magnetic resonance imaging features are presented in this case of arachnoiditis with arachnoid cyst formation, and cord tethering.

Cystic lumbar nerve sheath tumours: MRI features in five patients

Intraspinal cystic lumbar nerve sheath tumours constitute an uncommon subset of tumours with distinct clinico-biological behaviour. The MRI findings in five such cases are presented. Four of these were cystic schwannomas and one was a cystic neurofibroma. The pathology, MRI findings and the differential diagnosis of these rare tumours are analysed.

Imaging findings in rabies encephalitis

SUMMARY

Rabies encephalitis is perhaps one of the few infectious diseases that command attention and fear not only from the layman but also from physicians. The unique mode of transmission, the virtually exclusive neurotransmission shown by the agent, and the complete hopelessness of the established disease sets rabies apart from other zoonoses transmitted to man. Rabies encephalitis is a fatal disease and its diagnosis is usually based on the clinical presentations and findings. Hence, imaging in rabies is seldom done, and imaging findings in rabies encephalitis have rarely been described. We present the imaging findings in two confirmed cases of rabies encephalitis in which antemortem diagnosis was obtained by corneal impression smears showing the presence of viral antigens. The differential diagnosis of the imaging findings as well as the role and the relevance of imaging in the diagnosis of this disease are discussed. The current literature on the subject is also reviewed.

A longitudinal analysis of cytotoxic T lymphocyte precursor frequencies to the hepatitis B virus in chronically infected patients

Individuals with acute hepatitis B virus (HBV) infection characteristically mount a strong, multispecific cytotoxic T lymphocyte (CTL) response that is effective in eradicating virus. In contrast, this response in chronic carriers is usually weak or undetectable. Since it is generally acknowledged that HBV pathogenesis is immune-mediated, the occurrence of episodes of active liver disease in many carriers suggests that these individuals can mount active CTL responses to HBV. To see whether the detection of circulating CTLs is related to these flare episodes, we have determined the CTL precursor (CTLp) frequencies to HLA-A2-restricted viral peptides in seven patients over a 12-24-month period of their disease. Limiting dilution analyses (LDA) were performed longitudinally to five epitopes comprising the viral capsid (HBc), envelope (HBs) and polymerase (pol) proteins. Assays were performed against a mixture of peptides, or against each individual peptide, to measure overall CTL activity and the multispecificity of the responses, respectively. Since two of the patients were treated with recombinant human interleukin-12 (rHuIL-12) at the time, with one individual achieving complete disease remission a year later after being treated with interferon-alpha, we were also able to examine the effects of these cytokines on HBV cytotoxicity. Our results indicate that weak but detectable CTL responses do occur in chronic carriers which are generally associated with disease flares, although CTLps were also seen occasionally during minimal disease activity. The range of specificities varied between individuals and within each individual during the course of the disease. Finally, we also provide evidence that CTL reactivity is stimulated following treatment with certain cytokines, but is dependent on the time of administration.

Intramedullary tuberculomas. MR findings in seven patients

PURPOSE

To describe the MR findings in intramedullary tuberculomas and to discuss the usefulness of MR in the management of this pathology.

MATERIAL AND METHODS

A retrospective study of 7 patients from 21 to 60 years of age with clinical and radiological evidence of intramedullary tuberculomas was undertaken. Both T1- and T2-weighted images (WI) were obtained along with postcontrast T1WI. Signal intensities (SIs) of the granulomas were compared with SIs of the normal spinal cord.

RESULTS

Six patients showed focus of tuberculosis elsewhere in the body. Six out of 7 showed fusiform swelling of the cord. Ill-defined iso-intensity (in 4 patients) to hyperintensity (in 3 patients) was seen at the site of granuloma on T1WI. On T2WI, 2 patients revealed a hypointense area (with disc enhancement). An iso-hypointense rim was seen surrounding a hyperintense centre in 5 patients (with rim enhancement). Adjacent oedema was seen in all patients. In 2 patients meningeal enhancement was also seen. In 2 patients the histopathology following surgical biopsy confirmed the diagnosis. In the remaining 5 patients, another known focus of tuberculosis elsewhere in the body and a marked response to antitubercular treatment was considered confirmatory for tuberculomas.

CONCLUSION

Hypo- or iso-intensity on T2WI within the spinal cord with surrounding hyperintense oedema is suggestive of intramedullary tuberculomas. Central hyperintensities are also detected at times due to a variable amount of caseous necrosis with liquefaction. On T1WI, fusiform swelling of the cord is seen along with iso- to hyperintense foci, surrounded by hypointense oedema of the cord. Such findings should prompt a contrast-enhanced study, which may show single or conglomerate disc- or ring-enhancing lesions. MR thus plays an important role not only in detection and diagnosis, but also in deciding the treatment options and in the follow-up of those patients.

Tuberculosis of the sternum and clavicle: imaging findings in 15 patients

OBJECTIVE

To describe the imaging findings in sterno-clavicular tubercular involvement.

DESIGN AND PATIENTS

Fifteen patients with pathologically proven tuberculosis of the sternum and clavicle were retrospectively evaluated. Routine radiography, computed tomography (CT) and magnetic resonance imaging (MRI) were used in some or all of the patients. Clinical information and imaging features were evaluated in each case.

RESULTS

Eight patients had sternoclavicular joint (SCJ) involvement, five had isolated sternal involvement and two had isolated clavicular involvement. Seven patients were evaluated with only CT, six with only MRI and two with both. There were eight male and seven female patients, varying in age between 16 and 78 years. Fever, swelling and pain were common presenting symptoms. Two patients were HIV positive. Radiographs were positive in only eight patients. Destruction and signal intensity (SI) changes of the sternum and clavicle, destruction of the cartilage, soft tissue changes representing granulation tissue/abscess, displacement of the adjacent structures (vessels, trachea, etc.) and inflammatory changes in the adjacent structures in the form of cellulitis and myositis were common imaging features.

CONCLUSIONS

All imaging methods can provide complementary information regarding sterno-clavicular tubercular involvement that is helpful for determination of the therapy. MRI is useful in determining the extent of the lesion, particularly marrow involvement and soft tissue extent.

Imaging findings in a giant hepatic artery aneurysm

A rare case of relatively asymptomatic giant hepatic artery aneurysm of atherosclerotic aetiology is presented. The importance of imaging findings in the diagnosis of this condition and the differential diagnosis including the pertinent literature on the topic is discussed.

Activity-regulated, cytoskeleton-associated protein (Arc) is essential for visceral endoderm organization during early embryogenesis

Activity-regulated, cytoskeleton-associated protein (Arc) was first identified as an immediate-early gene regulated by synaptic activity. We have studied its functional role in vivo using a gene-targeting approach. We found that Arc is encoded by a single exon, and Arc mRNA is ubiquitously expressed in early mouse embryos. Homozygous Arc mutants are severely growth-retarded, fail to gastrulate and subsequently die before day 8.5 of embryogenesis. Further analysis revealed severe disorganization of visceral endoderm formation, and total separation and ectopic location of embryonic and extraembryonic structure. These findings demonstrate that Arc function is essential for early embryo development and patterning in mice, and support the hypothesis that signaling from visceral endoderm is essential for normal patterning of the extraembryonic and embryonic structure.

Phase I trial of subcutaneous recombinant human interleukin-12 in patients with advanced renal cell carcinoma

Patients with advanced renal cell carcinoma were treated in a Phase I trial with escalating doses of recombinant human interleukin-12 (rHuIL-12) given on days 1, 8, and 15 of each 28-day cycle. Treatment in the initial dose scheme consisted of a fixed dose with dose levels of 0.1, 0.5, and 1.0 microg/kg given to cohorts composed of three or six patients. On the basis of the toxicity profile, a second scheme (up-titration) was undertaken wherein rHuIL-12 was escalated for each patient from week 1 to week 2, to a target dose given week 3 and thereafter; cohort target dose levels were 0.5, 0.75, 1.0, 1.25, and 1.5 microg/kg. Fifty-one patients were treated: 32 (63%) had prior cytokine therapy and 19 (37%) had received no prior systemic therapy. The maximum tolerated dose for the fixed dose scheme was 1.0 microg/kg. Dose-limiting toxicities included increase in transaminase concentration, pulmonary toxicity, and leukopenia. The most severe toxicities occurred with the first injection and were milder upon further treatment. With the up-titration dose scheme, the maximum tolerated dose was reached at 1.5 microg/kg, and dose-limiting toxicity consisted of an increase in serum transaminase levels. At the maximum tolerated dose of 1.5 microg/kg, serum IL-12 levels increased to a mean peak level of 706 pg/ml. Serum levels of IFN-gamma increased to a mean peak level of about 200 pg/ml at 24 h after the first maintenance dose of 1.5 microg/kg. The best responses were as follows: one patient had complete response, 34 patients were stable, 14 patients showed progression, and 1 patient was inevaluable. In conclusion, rHuIL-12 was relatively well tolerated when administered by s.c. injection. The recommended dose according to the up-titration schedule of rHuIL-12 (microg/kg) for Phase II trials was as follows: cycle 1, 0.1 (day 1), 0.5 (day 8), 1.25 (day 15); cycle 2 onwards, 1.25. Phase II trials of rHuIL-12 were initiated in previously untreated patients with renal cell carcinoma and in patients with melanoma.

Autophor cementless total hip arthroplasty for osteoarthrosis secondary to congenital hip dysplasia

The authors present a consecutive series of 38 arthroplasties for osteoarthrosis secondary to hip dysplasia. All arthroplasties were performed by a single surgeon using Mittelmeier II (Autophor, Osteo AG, Selzach, Switzerland) ceramic cementless components. Crowe grades of subluxation were 60% grade I, 16% grade II, 12% grade III, and 12% grade IV. In all cases, the acetabular component was seated in the true acetabulum. The mean follow-up period was 75 months (range, 40-122 months). By the time of review, six hips (16%) had required revision for aseptic loosening, mainly of the femoral component. Good or excellent results were achieved in only 63% of the patients. In the group of surviving arthroplasties, the median Charnley hip scores before surgery were: pain, 2; movement, 3; and walking, 3. After surgery, the scores were: pain, 5; movement, 5; and walking, 6. All improvements were significant. The mean postoperative Harris hip score was 84. Poor scores were associated with contralateral hip disease (2 cases) and spina bifida (2 cases), significantly affecting function. The Autophor prosthesis can produce satisfactory results in some of these young patients with hip dysplasia. However, femoral loosening is a major problem and because of this, the authors have since changed to a newer stem design.

Prednimustine (Sterecyt) versus cyclophosphamide both in combination with methotrexate and 5-fluorouracil in the treatment of advanced breast cancer

153 women with advanced breast cancer were randomly allocated for treatment with SMF [prednimustine (Sterecyt) + methotrexate + 5-fluorouracil, 83 patients] or CMF (cyclophosphamide+methotrexate+5-fluorouracil, 70 patients). Prednimustine was administered orally 100 mg/m2 daily, for 5 days, and cyclophosphamide was administered orally 100 mg/m2, for 14 days, each, every 4 weeks. Methotrexate was given at a dose of 40 mg/m2 and 5-fluorouracil at 600 mg/m2 on day 1 and 8, every 4 weeks. Leucovorin was used in 39 patients to alleviate mucositis. The two treatment groups were balanced in terms of age, performance status, lymph node status, histology, menopausal status and previous therapy. Response was evaluated in 140 patients. Of 76 patients treated with SMF, 4 had a complete and 21 a partial response (CR+PR = 33%), 40 had no change (NC) and 11 had progressive disease (PD). Of 64 patients treated with CMF, 3 had a complete and 18 a partial response (CR+PR = 33%), 30 had no change (NC) and 13 had progressive disease (PD). Time to treatment failure and survival were similar in both groups. A relationship between haematological and gastrointestinal toxicity and therapeutic efficacy was demonstrated with a superior survival and response rate recorded for patients with such toxicity than in patients without. Haematological toxicity was, in general, mild to moderate with no difference between the two groups. Alopecia (P = 0.008), nausea/vomiting (P = 0.02) and euphoria (P = 0.03) were more common in the CMF-treated group. Diarrhoea was more common in the SMF group (P = 0.03). In conclusion, SMF seems to be as efficient as CMF with regard to response rate, time to treatment failure and survival. However, SMF was tolerated better than CMF.