Weeping sponge kidney: an unusual phenomenon that should be considered in cases of severe renal haemorrhage

AIM

To describe the clinical presentation, imaging evaluation, endovascular management, and outcomes of multifocal renal capsular haemorrhage, "weeping sponge kidney", and to identify associated risk factors and the pathophysiological mechanism behind this condition.

MATERIALS AND METHODS

This is a case series in which clinical information for each of the cases was collected retrospectively from electronic patient notes as well as the radiology information and picture archiving and communication systems.

RESULTS

Four consecutive cases were included in the series. All of the cases were treated successfully with embolisation. Three of the four patients had chronic renal failure with renal atrophy, which are patient factors that appear to be associated with multifocal renal capsular haemorrhage. Based on the procedural findings and the published literature, a pathophysiological mechanism is described to explain this condition and the relevance of the collateral arterial supply to the kidney in such cases is discussed.

CONCLUSION

Small subcapsular haematomas are usually self-limiting but in patients with renal failure, there may be an increased risk of developing a weeping sponge kidney, which can be life-threatening. The endovascular treatment for multifocal haemorrhage differs from that for a single bleeding point, especially if preservation of renal function is not a priority.

Human immunomodulatory ligand B7-1 mediates synaptic remodeling via the p75 neurotrophin receptor

Cell surface receptors, ligands, and adhesion molecules underlie development, circuit formation, and synaptic function of the central nervous system and represent important therapeutic targets for many neuropathologies. The functional contributions of interactions between cell surface proteins of neurons and nonneuronal cells have not been fully addressed. Using an unbiased protein-protein interaction screen, we showed that the human immunomodulatory ligand B7-1 (hB7-1) interacts with the p75 neurotrophin receptor (p75NTR) and that the B7-1:p75NTR interaction is a recent evolutionary adaptation present in humans and other primates, but absent in mice, rats, and other lower mammals. The surface of hB7-1 that engages p75NTR overlaps with the hB7-1 surface involved in CTLA-4/CD28 recognition, and these molecules directly compete for binding to p75NTR. Soluble or membrane-bound hB7-1 altered dendritic morphology of cultured hippocampal neurons, with loss of the postsynaptic protein PSD95 in a p75NTR-dependent manner. Abatacept, an FDA-approved therapeutic (CTLA-4-hFc fusion) inhibited these processes. In vivo injection of hB7-1 into the murine subiculum, a hippocampal region affected in Alzheimer's disease, resulted in p75NTR-dependent pruning of dendritic spines. Here, we report the biochemical interaction between B7-1 and p75NTR, describe biological effects on neuronal morphology, and identify a therapeutic opportunity for treatment of neuroinflammatory diseases.

High-resolution Compton spectroscopy using x-ray microcalorimeters

X-ray Compton spectroscopy is one of the few direct probes of the electron momentum distribution of bulk materials in ambient and operando environments. We report high-resolution inelastic x-ray scattering experiments with high momentum and energy transfer performed at a storage-ring-based high-energy x-ray light source facility using an x-ray transition-edge sensor (TES) microcalorimeter detector. The performance was compared with a silicon drift detector (SDD), an energy-resolving semiconductor detector, and Compton profiles were measured for lithium and cobalt oxide powders relevant to lithium-ion battery research. Spectroscopic analysis of the measured Compton profiles demonstrates the high-sensitivity to the low-Z elements and oxidation states. The line shape analysis of the measured Compton profiles in comparison with computed Hartree-Fock profiles is usually limited by the resolution of the semiconductor detector. We have characterized an x-ray TES microcalorimeter detector for high-resolution Compton scattering experiments using a bending magnet source at the Advanced Photon Source with a double crystal monochromator, providing monochromatic photon energies near 27.5 keV. The momentum resolution below 0.16 atomic units (a.u.) was measured, yielding an improvement of more than a factor of 7 over a state-of-the-art SDD for the same scattering geometry. Furthermore, the lineshapes of narrow valence and broad core electron profiles of sealed lithium metal were clearly resolved using an x-ray TES compared to smeared and broadened lineshapes observed when using the SDD. High-resolution Compton scattering using the energy-resolving area detector shown here presents new opportunities for spatial imaging of electron momentum distributions for a wide class of materials with applications ranging from electrochemistry to condensed matter physics.

Patient deprivation and perceived scan burden negatively impact the quality of whole-body MRI

AIM

To evaluate the association between the image quality of cancer staging whole-body magnetic resonance imaging (WB-MRI) and patient demographics, distress, and perceived scan burden.

MATERIALS AND METHODS

A sample of patients recruited prospectively to multicentre trials comparing WB-MRI with standard scans for staging lung and colorectal cancer were invited to complete two questionnaires. The baseline questionnaire, administered at recruitment, collated data on demographics, distress and co-morbidity. The follow-up questionnaire, completed after staging investigations, measured perceived WB-MRI scan burden (scored 1 low to 7 high). WB-MRI anatomical coverage, and technical quality was graded by a radiographic technician and grading combined to categorise the scan as "optimal", "sub-optimal" or "degraded". A radiologist categorised 30 scans to test interobserver agreement. Data were analysed using the chi-square, Fisher's exact, t-tests, and multinomial regression.

RESULTS

One hundred and fourteen patients were included in the study (53 lung, 61 colorectal; average age 65.3 years, SD=11.8; 66 men [57.9%]). Overall, 45.6% (n=52), scans were classified as "optimal" quality, 39.5% (n=45) "sub-optimal", and 14.9% (n=17) as "degraded". In adjusted analyses, greater deprivation level and higher patient-reported scan burden were both associated with a higher likelihood of having a sub-optimal versus an optimal scan (odds ratio [OR]: 4.465, 95% confidence interval [CI]: 1.454 to 13.709, p=0.009; OR: 1.987, CI: 1.153 to 3.425, p=0.013, respectively). None of the variables predicted the likelihood of having a degraded scan.

CONCLUSIONS

Deprivation and patients' perceived experience of the WB-MRI are related to image quality. Tailored protocols and individualised patient management before and during WB-MRI may improve image quality.

Affective problems and decline in cognitive state in older adults: a systematic review and meta-analysis

Evidence suggests that affective problems, such as depression and anxiety, increase risk for late-life dementia. However, the extent to which affective problems influence cognitive decline, even many years prior to clinical diagnosis of dementia, is not clear. The present study systematically reviews and synthesises the evidence for the association between affective problems and decline in cognitive state (i.e., decline in non-specific cognitive function) in older adults. An electronic search of PubMed, PsycInfo, Cochrane, and ScienceDirect was conducted to identify studies of the association between depression and anxiety separately and decline in cognitive state. Key inclusion criteria were prospective, longitudinal designs with a minimum follow-up period of 1 year. Data extraction and methodological quality assessment using the STROBE checklist were conducted independently by two raters. A total of 34 studies (n = 71 244) met eligibility criteria, with 32 studies measuring depression (n = 68 793), and five measuring anxiety (n = 4698). A multi-level meta-analysis revealed that depression assessed as a binary predictor (OR 1.36, 95% CI 1.05-1.76, p = 0.02) or a continuous predictor (B = -0.008, 95% CI -0.015 to -0.002, p = 0.012; OR 0.992, 95% CI 0.985-0.998) was significantly associated with decline in cognitive state. The number of anxiety studies was insufficient for meta-analysis, and they are described in a narrative review. Results of the present study improve current understanding of the temporal nature of the association between affective problems and decline in cognitive state. They also suggest that cognitive function may need to be monitored closely in individuals with affective disorders, as these individuals may be at particular risk of greater cognitive decline.

Structural and physico-chemical analysis of calcium/strontium substituted, near-invert phosphate based glasses for biomedical applications

Neutron diffraction, ²³Na and ³¹P NMR, and FTIR spectroscopy have been used to investigate the structural effects of substituting CaO with SrO in a 40P₂O₅·(16-x)CaO·20Na₂O·24MgO·xSrO glass, where x is 0, 4, 8, 12 and 16mol%. The ³¹P solid-state NMR results showed similar amounts of Q¹ and Q² units for all of the multicomponent glasses investigated, showing that the substitution of Sr for Ca has no effect on the phosphate network. The M-O coordinations (M=Mg, Ca, Sr, Na) were determined for binary alkali and alkaline earth metaphosphates using neutron diffraction and broad asymmetric distributions of bond length were observed, with coordination numbers that were smaller and bond lengths that were shorter than in corresponding crystals. The Mg-O coordination number was determined most reliably as 5.0(2). The neutron diffraction results for the multicomponent glasses are consistent with a structural model in which the coordination of Ca, Sr and Na is the same as in the binary metaphosphate glass, whereas there is a definite shift of Mg-O bonds to longer distance. There is also a small but consistent increase in the Mg-O coordination number and the width of the distribution of Mg-O bond lengths, as Sr substitutes for Ca. Functional properties, including glass transition temperatures, thermal processing windows, dissolution rates and ion release profiles were also investigated. Dissolution studies showed a decrease in dissolution rate with initial addition of 4mol% SrO, but further addition of SrO showed little change. The ion release profiles followed a similar trend to the observed dissolution rates. The limited changes in structure and dissolution rates observed for substitution of Ca with Sr in these fixed 40mol% P₂O₅ glasses were attributed to their similarities in terms of ionic size and charge.

STATEMENT OF SIGNIFICANCE

Phosphate based glasses are extremely well suited for the delivery of therapeutic ions in biomedical applications, and in particular strontium plays an important role in the treatment of osteoporosis. We show firstly that the substitution of strontium for calcium in bioactive phosphate glasses can be used to control the dissolution rate of the glass, and hence the rate at which therapeutic ions are delivered. We then go on to examine in detail the influence of Sr/Ca substitution on the atomic sites in the glass, using advanced structural probes, especially neutron diffraction. The environments of most cations in the glass are unaffected by the substitution, with the exception of Mg, which becomes more disordered.

The role of the defaecating pouchogram in the assessment of evacuation difficulty after restorative proctocolectomy and pouch-anal anastomosis

AIM

Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis (IPAA) is the most frequently performed operation for intractable ulcerative colitis (UC) and for many patients with familial adenomatous polyposis (FAP). It can be complicated by a functional evacuation difficulty, which is not well understood. We aimed to evaluate the role of defaecating pouchography in an attempt to assess the mechanism of evacuation difficulty in pouch patients.

METHOD

All RPC patients who had had a defaecating pouchogram for evacuation difficulty at one hospital between 2006 and 2014 were retrospectively reviewed. The findings and features were correlated with the symptoms. Demographic, clinical and radiological variables were analysed.

RESULTS

Eighty-seven [55 (63%) female] patients aged 47.6 ± 12.5 years (mean standard ± SD) were identified. Thirty-five had a mechanical outlet obstruction and 52 had no identified mechanical cause to explain the evacuation difficulty. The mean age of these 52 [33 (63%) female] patients was 48.2 ± 13 years. Of these 52 patients, significantly more used anti-diarrhoeal medication (P = 0.029), complained of a high frequency of defaecation (P = 0.005), experienced a longer time to the initiation of defaecation (P = 0.049) and underwent pouchoscopy (P = 0.003). Biofeedback appeared to improve the symptoms in 7 of 16 patients with a nonmechanical defaecatory difficulty. The most common findings on defaecating pouchography included residual barium of more than 33% after an attempted evacuation (46%, n = 24), slow evacuation (35%, n = 18) and mucosal irregularity (33%, n = 17). Correlation between radiological features and symptoms showed a statistically significant relationship between straining, anal pain, incontinence and urgency with patterns of anismus or pelvic floor descent or weakness seen on the defaecating pouchogram. Symptoms of incomplete evacuation, difficulty in the initiation of defaecation, high defaecatory frequency and abdominal pain were not correlated with the radiological features of the pouchogram.

CONCLUSION

Defaecating pouchography may be useful for identifying anismus and pelvic floor disorders in pouch patients who have symptoms of straining, anal pain or incontinence. In patients with a high frequency of defaecation and abdominal pain it does not provide clinically meaningful information. Patients who complain of straining, incontinence, anal pain or urgency and have anismus or pelvic floor disorders may benefit from behavioural therapy.

Drosophila KASH-domain protein Klarsicht regulates microtubule stability and integrin receptor localization during collective cell migration

During collective migration of the Drosophila embryonic salivary gland, cells rearrange to form a tube of a distinct shape and size. Here, we report a novel role for the Drosophila Klarsicht-Anc-Syne Homology (KASH) domain protein Klarsicht (Klar) in the regulation of microtubule (MT) stability and integrin receptor localization during salivary gland migration. In wild-type salivary glands, MTs became progressively stabilized as gland migration progressed. In embryos specifically lacking the KASH domain containing isoforms of Klar, salivary gland cells failed to rearrange and migrate, and these defects were accompanied by decreased MT stability and altered integrin receptor localization. In muscles and photoreceptors, KASH isoforms of Klar work together with Klaroid (Koi), a SUN domain protein, to position nuclei; however, loss of Koi had no effect on salivary gland migration, suggesting that Klar controls gland migration through novel interactors. The disrupted cell rearrangement and integrin localization observed in klar mutants could be mimicked by overexpressing Spastin (Spas), a MT severing protein, in otherwise wild-type salivary glands. In turn, promoting MT stability by reducing spas gene dosage in klar mutant embryos rescued the integrin localization, cell rearrangement and gland migration defects. Klar genetically interacts with the Rho1 small GTPase in salivary gland migration and is required for the subcellular localization of Rho1. We also show that Klar binds tubulin directly in vitro. Our studies provide the first evidence that a KASH-domain protein regulates the MT cytoskeleton and integrin localization during collective cell migration.

Stage T3a renal cell carcinoma: staging accuracy of CT for sinus fat, perinephric fat or renal vein invasion

OBJECTIVE

To study the accuracy of CT for staging T3a (TNM 2009) renal cell carcinoma (RCC).

METHODS

Unenhanced and nephrographic phase CT studies of 117 patients (male:female = 82:35; age range, 21-86 years) with T1-T3a RCC were independently reviewed by 2 readers. The presence of sinus or perinephric fat, or renal vein invasion and tumour characteristics were noted.

RESULTS

Median (range) tumour size was 5.5 (0.9-19.0) cm; and 46 (39%), 16 (14%) and 55 (47%) tumours were pT1, pT2 and pT3a RCC, respectively. The sensitivity/specificity for sinus fat, perinephric fat and renal vein invasion were 71/79%, 83/76% and 59/93% (Reader 1) and 88/71%, 68/72% and 69/91% (Reader 2) with κ = 0.41, 0.43 and 0.61, respectively. Sinus fat invasion was seen in 47/55 (85%) cases with T3a RCC vs 16/55 (29%) and 33/55 (60%) for perinephric fat and renal vein invasion. Tumour necrosis, irregularity of tumour edge and direct tumour contact with perirenal fascia or sinus fat increased the odds of local invasion [odds ratio (OR), 2.5-3.7; p < 0.05; κ = 0.42-0.61]. Stage T3a tumours were centrally located (OR, 3.9; p = 0.0009).

CONCLUSION

Stage T3a RCC was identified with a sensitivity of 59-88% and specificity of 71-93% (κ = 0.41-0.61). Sinus fat invasion was the most common invasive feature.

ADVANCES IN KNOWLEDGE

Centrally situated renal tumours with an irregular tumour edge, inseparable from sinus structures or the perirenal fascia and CT features of tumour necrosis should alert the reader to the possibility of Stage T3a RCC (OR, 2.5-3.9).

Ureteral obstruction following renal transplantation: causes, diagnosis and management

Renal transplantation, first performed successfully in the 1950s, is the treatment of choice for most patients with end-stage renal failure. It confers longer term survival and a better quality of life than do both haemodialysis and peritoneal dialysis. The success of renal transplantation is dependent on the preservation of renal graft function and despite the many advances in surgical techniques, immunosuppressive regimens and supportive therapies, many challenges remain including post-operative ureteral obstruction. This complication can pose a risk to graft, and, occasionally, to patient survival. In this pictorial review, we describe the causes of ureteral obstruction following renal transplantation and illustrate the pivotal role of radiology in both diagnosing and managing these complications.

Effect of Distraction Technique During Immunization to Reduce Behaviour Response Score (FLACC) to Pain in Toddlers

Introduction: Distraction techniques are important non pharmacological tools to reduce pain in infants and children. Few data are available regarding their effectiveness in toddlers. We have assessed effectiveness of audio-visual distraction techniques in toddlers during and after vaccination. Materials and Methods: The study used a quasi experimental three group pretest post test design. For all the three groups, the injections were administered by same staff nurse. Group- 1 (120 Patient) was encouraged to see and play with light and sound producing toy. Group- 2 (120 Patient) children were encouraged to see cartoon movie and children of control group- 3 (110 patient) were immunized without any distraction technique. A question form was used to determine the infant’s characteristics and the Face, Leg, Activity, Cry, Consolability (FLACC) Pain Scale was used to assess the level of pain. Data was collected between 1st April 2012 and 30th September 2012. Results: The mean pain score of test group during procedure (Group-1: 2.30 & Group-2: 3.65) were lower than the score of control group (Group-3: 5.30). Similarly after procedure Score (Group-1: 4.62 & Group-2: 2.79) were lower than the score of control group (Group-3: 6.20). Conclusion: The lower pain score in response to vaccination in test group indicates that distraction technique i.e. light & sound producing toys and cartoon movies are practical way to reduce pain during routine medical interventions in toddler. DOI: http://dx.doi.org/10.3126/jnps.v33i1.7017 J Nepal Paediatr Soc. 2013;33(1):25-30

Can MRI replace CT in evaluating semicircular canal dehiscence?

BACKGROUND AND PURPOSE

Patients with symptoms of semicircular canal dehiscence often undergo both CT and MR imaging. We assessed whether FIESTA can replace temporal bone CT in evaluating patients for SC dehiscence.

MATERIALS AND METHODS

We retrospectively reviewed 112 consecutive patients (224 ears) with vestibulocochlear symptoms who underwent concurrent MR imaging and CT of the temporal bones between 2007 and 2009. MR imaging protocol included a FIESTA sequence covering the temporal bone (axial 0.8-mm section thickness, 0.4-mm spacing, coronal/oblique reformations; 41 patients at 1.5T, 71 patients at 3T). CT was performed on a 64-row multidetector row scanner (0.625-mm axial acquisition, with coronal/oblique reformations). Both ears of each patient were evaluated for dehiscence of the superior and posterior semicircular canals in consensual fashion by 2 neuroradiologists. Analysis of the FIESTA sequence and reformations was performed first for the MR imaging evaluation. CT evaluation was performed at least 2 weeks after the MR imaging review, resulting in a blinded comparison of CT with MR imaging. CT was used as the reference standard to evaluate the MR imaging results.

RESULTS

For SSC dehiscence, MR imaging sensitivity was 100%, specificity was 96.5%, positive predictive value was 61.1%, and negative predictive value was 100% in comparison with CT. For PSC dehiscence, MR imaging sensitivity was 100%, specificity was 99.1%, positive predictive value was 33.3%, and negative predictive value was 100% in comparison with CT.

CONCLUSIONS

MR imaging, with a sensitivity and negative predictive value of 100%, conclusively excludes SSC or PSC dehiscence. Negative findings on MR imaging preclude the need for CT to detect SC dehiscence. Only patients with positive findings on MR imaging should undergo CT evaluation.

Radiofrequency ablation of large renal angiomyolipoma: median-term follow-up

PURPOSE

To study the feasibility of percutaneous radiofrequency ablation (RFA) of large angiomyolipomas (AMLs) using saline-cooled electrodes.

MATERIALS AND METHODS

Institutional Review Board approval for the study was received. Four patients (all female, age range 33-67 years) with large AMLs (maximal axis 6.1-32.4 cm) not suitable for embolotherapy or surgery consented to a trial of RFA. Procedures were performed under computerized tomographic guidance using 14G saline-infused electrodes. Two ablations (diameter 4-7 cm) were undertaken in each patient. Variables studied were technical success, treatment safety, alteration of tumor consistency, tumor size, effect on renal function, and medium-term freedom from haemorrhage.

RESULTS

All four patients underwent successful RFA without any intraprocedural complications. There has been no haemorrhage, or new renal specific symptom, during a minimum 48-month period, and normal renal function has been normal. On follow-up radiological imaging, the tumors have become fattier with involution of the soft-tissue elements (soft tissue-to-total tumor ratio decreased mean [range] of 0.26 [0.14-0.48] to 0.17 [0.04-0.34] U; p = 0.04 [paired Student t test]). Further evidence of treatment effect was the development of a capsule around the ablation zone, but there was no change in overall tumor volume (mean [range] 1,120 [118-2,845] to 1150 [90-3,013] ml; p = 1 [paired Student t test]).

CONCLUSION

RFA of large AMLs is technically feasible using saline-infused electrodes. The soft-tissue elements decreased in volume; the tumors become fattier; and there has been no renal haemorrhage during a 48-month period.

Investigation of erectile dysfunction

Erectile dysfunction (ED) represents a common and debilitating condition with a wide range of organic and non-organic causes. Physical aetiologies can be divided into disorders affecting arterial inflow, the venous occlusion mechanism or the penile structure itself. Various imaging modalities can be utilised to investigate the physical causes of ED, but penile Doppler sonography (PDS) is the most informative technique, indicated in those patients with ED who do not respond to oral pharmacological agents (e.g. phosphodiesterase type 5 inhibitors). This review will examine the anatomical and physiological basis of penile erection, the method for performing PDS and features of specific causes of ED, and will also consider the alternative imaging modalities available.

Priapism: pathophysiology and the role of the radiologist

Priapism is defined as a penile erection that persists for 4 h or longer and is unrelated to sexual activity. Its identification is important as lack of timely treatment (particularly of the low flow/ischaemic subgroup) can result in persisting erectile dysfunction as a consequence of irreversible corporal fibrosis. This review describes the physiology and anatomy of the normal erection, the aetiology and pathophysiology of the different types of priapism, and the role of the radiologist in the management of the condition. The treatment of iatrogenic priapism following intracavernosal injection of pharmacostimulant is discussed.

Applications of transrectal ultrasound in prostate cancer

Transrectal ultrasound (TRUS) was first developed in the 1970s. TRUS-guided biopsy, under local anaesthetic and prophylactic antibiotics, is now the most widely accepted method to diagnose prostate cancer. However, the sensitivity and specificity of greyscale TRUS in the detection of prostate cancer is low. Prostate cancer most commonly appears as a hypoechoic focal lesion in the peripheral zone on TRUS but the appearances are variable with considerable overlap with benign lesions. Because of the low accuracy of greyscale TRUS, TRUS-guided biopsies have become established in the acquisition of systematic biopsies from standard locations. The number of systematic biopsies has increased over the years, with 10-12 cores currently accepted as the minimum standard. This article describes the technique of TRUS and biopsy and its complications. Novel modalities including contrast-enhanced modes and elastography as well as fusion techniques for increasing the sensitivity of TRUS-guided prostate-targeted biopsies are discussed along with their role in the diagnosis and management of prostate cancer.

Transparent conducting films from NbSe3 nanowires

We have developed methods to disperse and partially size separate NbSe(3) nanowires in aqueous surfactant solutions. These dispersions can easily be formed into thin films. Optical and electrical studies show these films to display sheet resistances and transmittances ranging from (460 Ω/□, 22%) to (12 kΩ/□, 79%) depending on thickness. For thicker films, we measured the transparent conducting figure of merit to be σ(DC, B)/σ(Op) = 0.32, similar to graphene networks. Thickness measurements gave individual values of σ(Op) = 17,800 S m(-1) and σ(DC, B) = 5700 S m(-1). Films thinner than ∼ 70 nm displayed reduced DC conductivity due to percolative effects.

Diagnostic accuracy and value of magnetic resonance imaging (MRI) in planning exenterative pelvic surgery for advanced colorectal pelvic cancer

370

Background: Exenterative pelvic surgery is challenging and has been used in colorectal surgery to manage patients with advanced colorectal pelvic cancer. Resection of the tumor needs to be performed en-bloc and if feasible, without exposing the tumor, since this can compromise resection margins. This can only be performed through careful pre-operative staging. This study aimed to assess the diagnostic accuracy of MRI in detecting colorectal tumor invasion into seven intrapelvic compartments and its value in planning exenterative pelvic surgery.

Methods: Sixty four consecutive patients underwent preoperative MRI planning for exenterative surgery, for locally advanced (n= 23) and recurrent (n= 41) pelvic colorectal cancer. Two radiologists reported tumor invasion for each of the seven anatomic surgical resection compartments and were blinded to histopathology and intraoperative reference standards. Sensitivity, specificity and predictive values were calculated for each compartments. Kaplan-Meier methodology was used to calculate survival rates. Interobserver agreement was assessed using Cohen's Kappa coefficient (k).

Results: The sensitivity of MRI was ≥93.3% in all except for the lateral compartment where it was 89.3%. Its specificity for the posterior (82.2%), anterior below (86.4%) the peritoneal reflection compartments was lower compared to the rest of the compartments. MRI diagnosis of lateral (OR= 11.41, p= 0.033), anterior compartment above the peritoneal reflection (OR= 3.14, p= 0.005) and multicompartmental involvement (OR= 1.99, p<0.001) was associated with higher risk of incomplete resection which was subsequently found to be significant factor in predicting overall and disease free survival (p<0.05). The agreement between the two radiologists was found to be either good or very good for all the compartments (k>0.72).

Conclusions: MRI is highly accurate in predicting tumor invasion within the intrapelvic compartments and it should be the pre-operative staging modality of choice when considering exenterative surgery for patients with locally advanced colorectal pelvic cancer.

[Table: see text]

The added value of diffusion-weighted magnetic resonance imaging (DW-MRI) in the local staging of advanced colorectal pelvic cancer

378

Background: Surgeons rely on imaging to plan exenterative pelvic surgery for locally advanced primary and recurrent rectal cancer. Accurate local staging is vital in this process, as it provides information about the extent of the disease, facilitating the planning of the operation required to achieve complete resection. DW-MR imaging is a functional radiological modality that can provide indirect informationabout the water proton mobility within biologic tissue, without the need of a contrast agent. The aim of the present study was to assess the diagnostic accuracy and added value of diffusion DW-MRI in detecting colorectal tumor invasion into seven intrapelvic compartments for planning exenterative pelvic surgery.

Methods: Thirty three consecutive patients were preoperatively staged using DW-MRI to undergo exenterative surgery for locally advanced primary (n=12) and recurrent (n=21) colorectal pelvic cancer. Two radiologists reported tumor invasion for each of the seven anatomic surgical resection compartments and were blinded to histopathology and intraoperative reference standards. Accuracy, sensitivity, specificity and predictive values were calculated for the seven intrapelvic compartments. Interobserver agreement was assessed using Cohen's Kappa (k) coefficient for each compartment.

Results: The sensitivity of DW-MRI when used alone was low for all the compartments except the central (92%). Its specificity was very high for all the compartment (≥89.5%). Combining DW-MRI with conventional MRI increased the sensitivity for the lateral compartment by 8.3% to 100% and the specificity for the anterior compartment below the peritoneal reflection by 9.1% to 90.9%. The overall incremental value for the lateral compartment was 3%. The interobserver agreement was either good or very good (k≥0.669; p<0001) for all the compartments.

Conclusions: DW-MRI can improve the diagnostic accuracy of conventional MRI when staging patients with advanced colorectal pelvic cancer. Diffusion images are cheap and easy to obtain. Therefore DW-MRI should always be used in combination with conventional MRI when considering patients for exenterative pelvic surgery.

No significant financial relationships to disclose.

Magnetoresistance anisotropy of a one-dimensional superconducting niobium strip

We investigated confinement effects on the resistive anisotropy of a superconducting niobium strip with a rectangular cross section. When its transverse dimensions are comparable to the superconducting coherence length, the angle dependent magnetoresistances at a fixed temperature can be scaled as R(theta,H) = R(H/Hctheta) where Hctheta =Hc0(cos2theta + gamma(-2)sin2theta)(-1/2) is the angular dependent critical field, gamma is the width to thickness ratio, and Hc0 is the critical field in the thickness direction at theta=0 degrees . The results can be understood in terms of the anisotropic diamagnetic energy for a given field in a one-dimensional superconductor.

Systematic review of CT and MR perfusion imaging for assessment of acute cerebrovascular disease

BACKGROUND AND PURPOSE

Perfusion imaging sequences are an important part of imaging studies designed to provide information to guide therapy for treatment of cerebrovascular disease. The purpose of this study was to perform a meta-analysis of the medical literature on perfusion imaging to determine its role in clinical decision making for patients with acute cerebral ischemia.

MATERIALS AND METHODS

We searched MEDLINE by using a strategy that combined terms related to perfusion imaging with terms related to acute cerebral ischemia and brain tumors. We identified 658 perfusion imaging articles and classified them according to the clinical usefulness criteria of Thornbury and Fryback. We found 59 articles with promise of indicating usefulness in clinical decision making. We devised and implemented a clinical decision making scoring scale more appropriate to the topic of acute cerebral ischemia.

RESULTS

Several articles provided important insights into the physiologic processes underlying acute cerebral ischemia by correlation of initial perfusion imaging deficits with clinical outcome or ultimate size of the infarct. However, most articles showed relatively low relevance to influencing decisions in implementing treatment.

CONCLUSION

Most perfusion imaging articles are oriented toward important topics such as optimization of imaging parameters, determination of ischemia penumbra, and prediction of outcome. However, information as to the role of perfusion imaging in clinical decision making is lacking. Studies are needed to demonstrate that use of perfusion imaging changes outcome of patients with acute cerebral ischemia.

Hormonal factors concerned with liver regeneration

Hepatic regeneration in partially hepatectomized, eviscerated rats, and survival in mice infected with lethal doses of murine hepatitis virus, are both strikingly promoted by combined administration of insulin and glucagon. These two hormones, although potent promotors, fail as initiators of hepatocyte proliferation in animals with intact liver, which suggests a requirement for additional factors, probably derived from non-portal-splanchnic organs. We now find that continous intraperitoneal infusion of epidermal growth factor (EGF) initiates DNA synthesis, as determined by incorporation of [3H] thymidine, in livers of adult rats in vivo. The rise in DNA labelling, which is small with EGF alone, is augmented by addition to the infusion of either glucagon or insulin. This is in agreement with reports on adult hepatocytes in culture. Whether EGF has a physiological role in regulating liver growth under normal conditions in vivo remains to be determined.

A non-invasive method for detecting the metabolic stress response in rodents: characterization and disruption of the circadian corticosterone rhythm

Plasma corticosterone (CORT) measures are a common procedure to detect stress responses in rodents. However, the procedure is invasive and can influence CORT levels, making it less than ideal for monitoring CORT circadian rhythms. In the current paper, we examined the applicability of a non-invasive fecal CORT metabolite measure to assess the circadian rhythm. We compared fecal CORT metabolite levels to circulating CORT levels, and analyzed change in the fecal circadian rhythm following an acute stressor (i.e. blood sampling by tail veil catheter). Fecal and blood samples were collected from male adolescent rats and analyzed for CORT metabolites and circulating CORT respectively. Fecal samples were collected hourly for 24 h before and after blood draw. On average, peak fecal CORT metabolite values occurred 7-9 h after the plasma CORT peak and time-matched fecal CORT values were well correlated with plasma CORT. As a result of the rapid blood draw, fecal production and CORT levels were altered the next day. These results indicate fecal CORT metabolite measures can be used to assess conditions that disrupt the circadian CORT rhythm, and provide a method to measure long-term changes in CORT production. This can benefit research that requires long-term glucocorticoid assessment (e.g. stress mechanisms underlying health).