Impact of climate change and management strategies on water and salt balance of the polders and islands in the Ganges delta.

Enhancing crop production, particularly by growing a crop in the typically-fallow dry season is a key strategy for alleviating poverty in the Ganges delta region. We used a polder water and salt balance model to examine the impact of several crop management, salt management and climate change scenarios on salinity and crop evapotranspiration at Dacope and Amtali in Bangladesh and Gosaba in India. A key (and unsurprising) finding is that salt management is very important, particularly at the two drier sites, Dacope and Gosaba. Good salt management lowers salinity in the shallow groundwater, soil and water storage ponds, and leads to more irrigation. Climate change is projected to alter rainfall, and this in turn leads to modelled increases or decreases in runoff from the polders, and thence affect salt concentrations in the soil and ponds and canals. Thus, the main impacts of climate change are through the indirect impacts on salt concentrations, rather than the direct impacts of the amount of water supplied as rainfall. Management practices to remove salt from polders are therefore likely to be effective in combatting the impacts of projected climate change particularly at Dacope and Gosaba.

Assessing irrigated agriculture's surface water and groundwater consumption by combining satellite remote sensing and hydrologic modelling.

Globally, irrigation accounts for more than two thirds of freshwater demand. Recent regional and global assessments indicate that groundwater extraction (GWE) for irrigation has increased more rapidly than surface water extraction (SWE), potentially resulting in groundwater depletion. Irrigated agriculture in semi-arid and arid regions is usually from a combination of stored surface water and groundwater. This paper assesses the usefulness of remotely-sensed (RS) derived information on both irrigation dynamics and rates of actual evapotranspiration which are both input to a river-reach water balance model in order to quantify irrigation water use and water provenance (either surface water or groundwater). The assessment is implemented for the water-years 2004/05-2010/11 in five reaches of the Murray-Darling Basin (Australia); a heavily regulated basin with large irrigated areas and periodic droughts and floods. Irrigated area and water use are identified each water-year (from July to June) through a Random Forest model which uses RS vegetation phenology and actual evapotranspiration as predicting variables. Both irrigated areas and actual evapotranspiration from irrigated areas were compared against published estimates of irrigated areas and total water extraction (SWE+GWE).The river-reach model determines the irrigated area that can be serviced with stored surface water (SWE), and the remainder area (as determined by the Random Forest Model) is assumed to be supplemented by groundwater (GWE). Model results were evaluated against observed SWE and GWE. The modelled SWE generally captures the observed interannual patterns and to some extent the magnitudes, with Pearson's correlation coefficients >0.8 and normalised root-mean-square-error<30%. In terms of magnitude, the results were as accurate as or better than those of more traditional (i.e., using areas that fluctuate based on water resource availability and prescribed crop factors) irrigation modelling. The RS irrigated areas and actual evapotranspiration can be used to: (i) understand irrigation dynamics, (ii) constrain irrigation models in data scarce regions, as well as (iii) pinpointing areas that require better ground-based monitoring.

Computed tomography features associated with operative management for nonstrangulating small bowel obstruction.

BACKGROUND: The management of nonstrangulating small bowel obstruction (SBO) may require surgery, but the need for and timing of surgical intervention isn't always apparent. We sought to determine whether specific features on computed tomography (CT) can predict the necessity for operative management. METHODS: Two radiologists independently reviewed CT scans from all patients admitted to hospital with SBO between 2004 and 2006. We examined the association between radiographic features and operative management by univariate analysis using the χ(2) or Fisher exact test. Significant factors with high concordance between radiologists were entered into a multivariable stepwise logistic regression model. RESULTS: There were 228 patients with SBO, 63 of whom met our inclusion criteria and had CT scans available for review. Three CT features were frequently associated with operative management and had good concordance between radiologists: complete bowel obstruction, small bowel dilation greater than 4 cm and transition point. Transition point was the only significant factor predictive of operative management for SBO on multivariable logistic regression analysis (OR 19, 95% confidence interval 1.8-201, p = 0.014). CONCLUSION: In patients with nonstrangulating SBO, the presence of a transition point on CT scan should alert the surgeon to the increased likelihood that operative management may be required.

CONTEXTE: La prise en charge de l'occlusion du grêle sans étranglement peut nécessiter une chirurgie, mais il n'y a pas de règles claires pour déterminer le bien-fondé et le moment de l'intervention. Nous avons voulu déterminer si certaines caractéristiques spécifiques observées à la tomodensitométrie (TDM) permettent de prédire la nécessité d'une prise en charge chirurgicale. MÉTHODES: Deux radiologistes ont passé en revue de manière indépendante les TDM de tous les patients hospitalisés pour obstruction du grêle entre 2004 et 2006. Nous avons analysé le lien entre les caractéristiques radiographiques et la prise en charge chirurgicale par analyse univariée à l'aide du test du χ2 ou du test exact de Fisher. Les facteurs importants assortis d'une étroite concordance entre les radiologistes ont été intégrés à un modèle de régression logistique multivariée séquentielle. RÉSULTATS: On a dénombré 228 patients atteints d'une occlusion du grêle, dont 63 répondaient à nos critères d'inclusion et pour lesquels on disposait de résultats de TDM à soumettre à l'examen des radiologistes. Trois caractéristiques à la TDM ont fréquemment été associées à la prise en charge chirurgicale, en plus de faire l'objet d'une bonne concordance entre les radiologistes : obstruction intestinale complète, dilatation du grêle de plus de 4 cm et point de transition (ou saut de calibre). Le point de transition a été le seul facteur prédictif important à l'égard de la prise en charge chirurgicale de l'occlusion du grêle à l'analyse de régression logistique multivariée (rapport de cotes 19; intervalle de confiance de 95 %, 1,8­201; p = 0,014). CONCLUSION: Chez les patients qui présentent une occlusion du grêle sans étranglement, la présence d'un point de transition à la TDM devrait indiquer au chirurgien une plus grande probabilité de traitement chirurgical nécessaire.

Linguistic history of posterior reversible encephalopathy syndrome: mirror of developing knowledge.

BACKGROUND: the term posterior reversible encephalopathy syndrome (PRES) was first proposed in 2000. Since then, the acronym PRES has become very popular in imaging and clinical literature as it is short, easy to say and remember, and neatly couples the frequent localization of neuroimaging findings along with the typical outcome of this syndrome. Another possible reason for the popularity of this acronym in clinical circles is the connotation of PRES with (elevated blood) PRESsure, as a majority of cases are believed to be associated with hypertension. However, problems exist with the interpretation and common understanding of PRES, questioning the appropriateness of "P" and "R" in the acronym. The linguistic issues related to the acronym of PRES are interesting. OBJECTIVES: the aim of this work is to analyze the controversies related to the acronym of PRES. RESULTS: in 2006, modifying the meaning of the acronym was suggested, renaming it Potentially Reversible Encephalopathy Syndrome in order to adjust to the cases when posterior involvement is not prominent and emphasize that the reversibility is not spontaneous. This meant the creation of a backronym, where the new phrase is constructed by starting with an existing acronym. CONCLUSION: this new backronym indicates that the original acronym of PRES has become a misnomer.

Displacement of the temporomandibular joint disk: correlation between clinical findings and MRI characteristics.

BACKGROUND AND OBJECTIVE: Disk displacement frequently causes dysfunction of the temporomandibular joint (TMJ). Magnetic resonance imaging (MRI) of the TMJ is 95% accurate in the assessment of disk position and form. Various restorative procedures are used for treatment of disk displacement. However, several authors have noted a lack of correlation between MRI findings of disk displacement and the extent of pain and dysfunction of the TMJ. The purpose of this study was to evaluate whether MRI findings of various degrees of disk displacement could be correlated with the presence of clinical signs and symptoms in patients with a clinical disorder of the TMJ. MATERIALS AND METHODS: One hundred and forty-four TMJs (in 72 patients) were imaged. Displacement of the posterior band in relation to the condyle was quantified as mild or significant. RESULTS: Disk displacement was found in 45 (54%) of the 84 symptomatic joints and 13 (22%) of the 60 asymptomatic joints. Among the 84 symptomatic joints, 31 (37%) had disk displacement with reduction and 14 (17%) had disk displacement without reduction. In the latter group, 11 (79%) of the 14 joints had significant displacement of the posterior band (8 or 9 o'clock) and 21% had mild displacement of the posterior band (10 o'clock). Of the 60 clinically asymptomatic joints, 47 (78%) had no signs of disk displacement on MRI, whereas 13 (22%) had disk displacement with reduction. None of the asymptomatic joints had disk displacement without reduction. The difference in occurrence of disk displacement between symptomatic and asymptomatic joints was statistically significant (54% vs. 22%; p < 0.001). However, the difference in occurrence of disk displacement with reduction of the disk on mouth opening was not statistically significant (37% vs. 22%; p = 0.06). CONCLUSIONS: Disk displacement on MRI correlated well with clinical symptoms in cases of significant disk displacement and in cases of disk displacement without reduction. When disk displacement with reduction was mild, there was no statistically significant difference between symptomatic and asymptomatic joints, which suggests that other causes should be considered.

Can CT replace MRI in preoperative assessment of the circumferential resection margin in rectal cancer?

UNLABELLED: The surgical circumferential resection margin in total mesorectal excision surgery is defined by the relationship of the tumor to the mesorectal fascia. Patients with anticipated tumor invasion of the mesorectal fascia receive neoadjuvant therapy to downstage/downsize the tumor and to obtain tumor-free resection margins.Tumor relationship to the mesorectal fascia is accurately determined by MRI. Compared with MRI, multidetector-row computed tomography is more widely available, faster, less costly, and provides the ability to simultaneously assess the liver, peritoneum, and retroperitoneum for metastases. PURPOSE: The objective of this study was to compare the accuracy of multidetector-row CT with conventional MRI in diagnosis of rectal cancer invasion of the mesorectal fascial envelope. MATERIALS AND METHODS: During a 2-year period, all patients were enrolled in this study who had biopsy-proven rectal carcinoma and were referred, as a part of the routine preoperative staging workup, for a CT scan of the abdomen and pelvis and also an MRI of the pelvis.All examinations were reviewed independently by 2 radiologists who were blinded from one another, from the findings of the other modality, and from clinical information. Both observers were dedicated abdominal radiologists who are experienced in reading pelvic CT and MRI. Categorical agreement between MRI and multidetector-row CT for all the evaluated parameters of the tumor position, mesorectal fascia, and lymph nodes, as well as the interobserver agreement between CT and MRI, was determined by the intraclass correlation weighted kappa statistic to measure the data set's consistency. RESULTS: Among the study's 92 patients, the tumor characteristics suggested by multidetector-row CT agreed with those of MRI, with a weighted kappa ranging from 0.488 to 0.748 for the first reader and 0.577 to 0.800 for the second reader. Interobserver agreement ranged from 0.506 to 0.746.Agreement regarding mesorectal fascia characteristics differed significantly between multidetector-row CT and MRI, depending on the level of assessment. In the distal rectum, agreement was 0.207 for the first reader and 0.385 for the second reader. In the mid rectum, agreement was 0.420 and 0.527, respectively, and in the proximal rectum agreement was 0.508 and 0.520. Interobserver agreement was 0.737 at the distal level and 0.700 at the mid and proximal levels. Agreement regarding measurement of the distance from the tumor to the mesorectal fascia was 0.425 for the first reader and 0.723 for the second reader, with interobserver agreement of 0.766. Agreement in assessment of the number of lymph nodes ranged from 0.743 to 0.787 for the first reader and 0.754 to 0.840 for the second reader. Interobserver agreement ranged from 0.779 to 0.841. Agreement in assessment of the size of the lymph nodes ranged from 0.540 to 0.830 for the first reader and 0.850 to 0.940 for the second reader. Interobserver agreement ranged from 0.900 to 0.920. Agreement in assessment of the distance from nodes to the mesorectal fascia was 0.320 for the first reader and 0.401 for the second reader, with interobserver agreement of 0.950. CONCLUSION: The results of this study differ from previously published data by demonstrating substantial agreement between readers in multidetector-row CT assessment of the tumor, mesorectal fascia, and lymph nodes. With the exceptions of mesorectal fascia in the distal rectum and the distance from the nodes to mesorectal fascia, other evaluated parameters were assessed with moderate and substantial agreement between multidetector-row CT and MRI. However, our findings suggest that multidetector-row CT does not correlate well enough with MRI findings to replace it in rectal cancer staging.

Arterial embolization for primary postpartum hemorrhage.

PURPOSE: To evaluate the efficacy and safety of arterial embolization (AE) for treatment of primary postpartum hemorrhage (PPH), and the factors associated with clinical success. MATERIAL AND METHODS: A retrospective analysis of all patients undergoing AE for primary PPH at three institutions (N = 43) from 1996 through 2007 was conducted. Patients with an antepartum diagnosis of invasive placenta were excluded from the study. Mean patient age was 31 years +/- 5 (range, 21-40 y). Eighteen women (42%) were primiparous. Delivery details, transfusion requirements, hematology and coagulation results, embolization details, and clinical outcomes were collected. Clinical success was defined as cessation of bleeding without the need for repeat embolization, laparotomy, or hysterectomy after embolization; or death. The Fisher exact test was used to analyze nonparametric data. RESULTS: The clinical success rate was 79% (n = 34). Four patients underwent successful repeat embolization. Two of 35 patients who had not undergone hysterectomy before embolization underwent hysterectomy for continued bleeding (without repeat embolization). One underwent hysterectomy 2 weeks after AE for uterine necrosis. One of eight patients who had undergone hysterectomy before AE required a laparotomy for a large retroperitoneal hematoma, and one patient died from cerebral anoxia secondary to hypotension despite repeat embolization. Clinical success was not related to mode of delivery, cause of PPH, transfusion requirements, time from delivery to embolization, or hysterectomy before AE (P > .05). Patients with active extravasation visualized angiographically were more likely to require repeat embolization (five of 13 [38%] vs 0 of 30 without extravasation; P < .01). CONCLUSIONS: AE for primary PPH is safe and effective. Repeat embolization may be necessary in patients with active extravasation on angiography.

Abdominal manifestations of systemic lupus erythematosus: spectrum of imaging findings.

Systemic lupus erythematosus is an immune-mediated syndrome in which the immune response is to non-organ-specific antigens, and virtually every organ in the abdominal cavity may become involved. Only renal involvement forms part of the diagnostic criteria, however, a combination of typically nonspecific findings, including peritoneal surface, enteric, renal, renal tract, pancreatic, adrenal, hepatobiliary, and splenic manifestations, should be looked for in patients with known lupus or other connective tissue disease who are undergoing abdominal imaging and may suggest the diagnosis in patients presenting with an acute abdomen. Our work presents the spectrum of imaging findings of abdominal manifestations of systemic lupus erythematosus.

Hurthle cell neoplasms of the thyroid: sonographic appearance and histologic characteristics.

OBJECTIVE: The purpose of this study was to determine the sonographic features of Hürthle cell neoplasms (HCNs) of the thyroid. METHODS: We retrospectively analyzed the sonographic appearance of 15 histologically proven HCNs in 15 patients aged 16 to 70 years (mean age, 44 years). Sonographic features that were reviewed included the size and echogenicity of the tumors, the presence of cystic areas or calcifications, and detectable blood flow on color Doppler imaging. Correlation of sonographic findings with pathologic results was performed. RESULTS: The tumors ranged from 0.4 to 7 cm in diameter, but most were less than 3 cm in diameter. Four (27%) of the 15 tumors were homogeneously hypoechoic. Two tumors (13%) were predominantly hypoechoic with isoechoic areas to thyroid parenchyma. Two (13%) neoplasms were isoechoic to thyroid parenchyma. Four (27%) tumors were predominantly isoechoic, containing hypoechoic areas, and 3 (20%) tumors were hyperechoic. Three neoplasms contained cystic components. None of the tumors contained calcifications. One tumor was avascular on Doppler examination. One neoplasm showed only peripheral blood flow. Thirteen tumors showed internal vascularity, 7 of them with peripheral blood flow. Twelve HCNs were benign, and 3 were malignant on pathologic examination. CONCLUSIONS: Hürthle cell neoplasms show a spectrum of sonographic appearances from predominantly hypoechoic to hyperechoic lesions and from peripheral blood flow with no internal flow to extensively vascularized lesions. Pathologic criteria differentiating benign and malignant HCNs (absence or presence of a capsular breach, vascular or extrathyroidal tissue invasion, nodal involvement, and distant metastasis) are beyond the resolution of sonography and fine-needle aspiration biopsy and require removal of the entire lesion. This precludes diagnosis and characterization of HCNs by sonography.

Vascular complications of pancreatitis: imaging and intervention.

The objective of this study was to highlight technical challenges and potential pitfalls of diagnostic imaging, intervention, and postintervention follow-up of vascular complications of pancreatitis. Diagnostic and interventional radiology imaging from patients with pancreatitis from 2002 to 2006 was reviewed. We conclude that biphasic CT is the diagnostic modality of choice. Catheter angiography may (still) be required to diagnose small pseudoaneurysms. Endovascular coiling is the treatment of choice for pseudoaneurysms. Close clinical follow-up is required, as patients may rebleed/develop aneurysms elsewhere.

Computed tomography angiography in abdominal aortic endoleaks: what is the optimal protocol?

OBJECTIVE: To evaluate the roles of noncontrast and delayed phases of computed tomography angiography (CTA) for optimization of the CTA protocol in endoleak detection. METHODS: CTAs of patients who underwent abdominal aortic endovascular stent-graft placement were retrospectively reviewed. CTA comprised noncontrast, arterial, and delayed phase (2 minutes postcontrast). The arterial phase was compared with a combined arterial and delayed phase and followed by the noncontrast phase to see whether additional information was obtained. RESULTS: Thirty-eight CTA studies demonstrated endoleak. In 30 studies (79%; 95%CI 64% to 89%), endoleak was detected in the arterial phase. Eight studies (21%; 95%CI 11% to 36%) demonstrated an endoleak only in the delayed phase. No additional information was obtained in the noncontrast phase when compared with a combined reading of the arterial and delayed phases (95%CI 0% to 9%). CONCLUSION: Delayed-phase imaging is necessary for endoleak detection and obviates a noncontrast phase. Identical parameters should be used for arterial and delayed phases.