Histology of Convergent Probing Appendages in Mormyridae.

Mormyridae is an early diverging family of Teleostean fishes that produce an electric field for navigation and communication using an electric organ. This clade has a diverse array of soft-tissue rostral appendages, such as the chin-swelling, the Schnauzenorgan, and the tubesnout combined with a Schnauzenorgan, that have evolved multiple times. Here we assess if macroscopically convergent, soft-tissue rostral appendages are also histologically convergent. Further, we investigate how the histology of these appendages can inform their function. We sampled independent gains of the chin-swelling and Schnauzenorgan to understand similarities and differences in their anatomies. We show that macroscopically convergent rostral appendages are also convergent at a histological level, and different types of rostral appendages share a similar anatomy; that said, minor differences likely relate to their specific functions. Based on a comparison of the skeletal muscle distribution and the differing attachment shapes of each appendage to the dentary, we conclude that the Schnauzenorgan is capable of a wider range of movements than the chin swelling. Furthermore, the anatomy suggests that these soft-tissue rostral appendages likely function as electrosensory foveas (i.e., an appendage that focuses a sensory system). Lastly, these histological data support the hypothesis that the chin swelling may be a precursor to the Schnauzenorgan.

ResumenMormyridae es una de las primeras familias divergentes de peces teleósteos que producen un campo eléctrico para la navegación y la comunicación mediante un órgano eléctrico. Este clado tiene una variedad diversa de apéndices rostrales de tejidos blandos, como el mentón hinchado, el Schnauzenorgan y el hocico tubular combinado con un Schnauzenorgan, que han evolucionado varias veces. Aquí evaluamos si los apéndices rostrales de tejido blando macroscópicamente convergentes también son histológicamente convergentes. Además, investigamos cómo la histología de estos apéndices puede informar sus funciones. Tomamos muestras de ganancias independientes del mentón hinchado y del Schnauzenorgan para comprender las similitudes y diferencias en sus anatomías. Mostramos que los apéndices rostrales macroscópicamente convergentes también lo son a nivel histológico, y diferentes tipos de apéndices rostrales comparten una anatomía similar; dicho esto, es probable que las diferencias menores se relacionen con sus funciones específicas. Con base en una comparación de la distribución del músculo esquelético y las diferentes formas de unión de cada apéndice al dentario, concluimos que el Schnauzenorgan es capaz de realizar una gama más amplia de movimientos que el mentón hinchado. Además, la anatomía sugiere que estos apéndices rostrales de tejido blando probablemente funcionen como fóveas electrosensoriales (es decir, un apéndice que enfoca un sistema sensorial). Por último, estos datos histológicos apoyan la hipótesis de que el mentón hinchado puede ser un precursor del Schnauzenorgan.

Distinguishing globally-driven changes from regional- and local-scale impacts: The case for long-term and broad-scale studies of recovery from pollution.

Marine ecosystems are subject to anthropogenic change at global, regional and local scales. Global drivers interact with regional- and local-scale impacts of both a chronic and acute nature. Natural fluctuations and those driven by climate change need to be understood to diagnose local- and regional-scale impacts, and to inform assessments of recovery. Three case studies are used to illustrate the need for long-term studies: (i) separation of the influence of fishing pressure from climate change on bottom fish in the English Channel; (ii) recovery of rocky shore assemblages from the Torrey Canyon oil spill in the southwest of England; (iii) interaction of climate change and chronic Tributyltin pollution affecting recovery of rocky shore populations following the Torrey Canyon oil spill. We emphasize that "baselines" or "reference states" are better viewed as envelopes that are dependent on the time window of observation. Recommendations are made for adaptive management in a rapidly changing world.

Hydrogel versus Bare Platinum Coils in Patients with Large or Recurrent Aneurysms Prone to Recurrence after Endovascular Treatment: A Randomized Controlled Trial.

BACKGROUND AND PURPOSE: Some patients are at high risk of aneurysm recurrence after endovascular treatment: patients with large aneurysms (Patients Prone to Recurrence After Endovascular Treatment PRET-1) or with aneurysms that have previously recurred after coiling (PRET-2). We aimed to establish whether the use of hydrogel coils improved efficacy outcomes compared with bare platinum coils. MATERIALS AND METHODS: PRET was an investigator-led, pragmatic, multicenter, parallel, randomized (1:1) trial. Randomized allocation was performed separately for patients in PRET-1 and PRET-2, by using a Web-based platform ensuring concealed allocation. The primary outcome was a composite of a residual/recurrent aneurysm, adjudicated by a blinded core laboratory, or retreatment, intracranial bleeding, or mass effect during the 18-month follow-up. Secondary outcomes included adverse events, mortality, and morbidity (mRS > 2). The hypothesis was that hydrogel would decrease the primary outcome from 50% to 30% at 18 months, necessitating 125 patients per group (500 for PRET-1 and PRET-2). RESULTS: The trial was stopped once 250 patients in PRET-1 and 197 in PRET-2 had been recruited because of slow accrual. A poor primary outcome occurred in 44.4% (95% CI, 35.5%-53.2%) of those in PRET-1 allocated to platinum compared with 52.5% (95% CI, 43.4%-61.6%) of patients allocated to hydrogel (OR, 1.387; 95% CI, 0.838-2.295; P = .20) and in 49.0% (95% CI, 38.8%-59.1%) in PRET-2 allocated to platinum compared with 42.1% (95% CI, 32.0%-52.2%) allocated to hydrogel (OR, 0.959; 95% CI, 0.428-1.342; P = .34). Adverse events and morbidity were similar. There were 3.6% deaths (1.4% platinum, 5.9% hydrogel; P = .011). CONCLUSIONS: Coiling of large and recurrent aneurysms is safe but often poorly effective according to angiographic results. Hydrogel coiling was not shown to be better than platinum.

Direct comparison of Neuroform and Enterprise stents in the treatment of wide-necked intracranial aneurysms.

AIM: To compare the complications and outcomes of Neuroform and Enterprise stents in the treatment of unruptured wide-necked aneurysms. MATERIALS AND METHODS: Under the auspices of the institutional review board, a review of a prospectively collected patient log identified 130 patients who underwent elective stent-assisted coil embolization of a wide-necked aneurysm, including 53 patients treated with an Enterprise stent and 77 patients treated with a Neuroform stent. Immediate and long-term clinical and radiographic outcomes were recorded for all patients. All patient data were handled in accordance with Health Insurance Portability and Accountability Act of 1996 (HIPAA) regulations. RESULTS: The technical success rate was 94%. Overall morbidity was 15% with Enterprise stents and 3% with Neuroform stents (p = 0.020). However, the type of stent used was not predictive of clinical outcomes as measured by the modified Rankin scale. In a multivariate analysis, the use of a Neuroform stent was one of the predictors of retreatment (p = 0.034). CONCLUSION: Multivariate analyses identified the use of Neuroform stents as an independent predictor of the need for retreatment and the use of Enterprise stents as an independent predictor of morbidity. However, the type of stent was not predictive of clinical outcome as measured by the modified Rankin scale.

Vision outcomes and major complications after endovascular coil embolization of ophthalmic segment aneurysms.

BACKGROUND AND PURPOSE: As aneurysms arising from the ophthalmic segment of the internal carotid artery increase in size, they can compress the optic nerve, prompting patients to present with visual disturbances. The purpose of this article is to describe the clinical and angiographic results with an emphasis on visual outcomes following the endovascular treatment of ophthalmic segment ICA aneurysms. MATERIALS AND METHODS: The records of 1254 patients who presented for endovascular treatment of a cerebral aneurysm were retrospectively reviewed to identify 65 consecutive patients who underwent coil embolization of an ophthalmic segment ICA aneurysm. The clinical records, treatment reports, and imaging were reviewed with a focus on visual outcomes. RESULTS: Twenty-two of the 65 patients (34%) who presented for treatment of an ophthalmic aneurysm reported a visual disturbance at presentation. Fifteen of the 22 patients (68%) experienced an improvement in their symptoms after treatment. Overall, patients with visual symptoms were significantly more likely to benefit from treatment than to have a decline in vision (P = .03). The overall morbidity was 4%, and mortality was 0%. The retreatment rate was high at 30%, though this was disproportionately weighted by an 86% retreatment rate in patients with ruptured aneurysms. CONCLUSIONS: Patients with visual symptoms attributable to ophthalmic segment ICA aneurysms undergoing endovascular coil embolization were statistically more likely to experience an improvement in their vision than to have worsening or unchanged vision. Coiling was associated with a low morbidity rate, though an elevated retreatment rate.

Patients prone to recurrence after endovascular treatment: periprocedural results of the PRET randomized trial on large and recurrent aneurysms.

BACKGROUND AND PURPOSE: Some patients with large or recurrent aneurysms may be at increased risk of recurrence postcoiling. The Patients Prone to Recurrence after Endovascular Treatment (PRET) trial was designed to assess whether hydrogel coils were superior to platinum coils in these high-risk patients. This article reports periprocedural safety and operator-assessed angiographic results from the PRET trial. MATERIALS AND METHODS: PRET was a pragmatic, multicenter, randomized controlled trial. Patients had ≥10-mm aneurysms (PRET-1) or a major recurrence after coiling of an aneurysm of any size (PRET-2). Patients were randomly allocated to hydrogel or control arms (any platinum coil) by using concealed allocation with minimization. Assist devices could be used as clinically required. Aneurysms could be unruptured or recently ruptured. Analyses were on an intent-to-treat basis. RESULTS: Four hundred forty-seven patients were recruited (250 PRET-1; 197 PRET-2). Aneurysms were recently ruptured in 29% of PRET-1 and 4% of PRET-2 patients. Aneurysms were ≥10 mm in all PRET-1 and in 50% of PRET-2 patients. They were wide-neck (≥4 mm) in 70% and in the posterior circulation in 24% of patients. Stents were used in 28% of patients (35% in PRET-2). Coiling was successful in 98%. Adverse events occurred in 28 patients with hydrogel and 23 with platinum coils. Mortality (n=2, unrelated to treatment) and morbidity (defined as mRS>2 at 1 month) occurred in 25 patients (5.6%; 12 hydrogel, 13 platinum), related to treatment in 10 (4 hydrogel; 6 platinum) (or 2.3% of 444 treated patients). No difference was seen between hydrogel and platinum for any of the indices used to assess safety up to at least 30 days after treatment. At 1 month, 95% of patients were home with a good outcome (mRS≤2 or unchanged). Operator-assessed angiographic outcomes were satisfactory (complete occlusion or residual neck) in 339 of 447 or 76.4% of patients, with no significant difference between groups. CONCLUSIONS: Endovascular treatment of large and recurrent aneurysms can be performed safely with platinum or hydrogel coils.

Preoperative embolization of intracranial meningiomas: efficacy, technical considerations, and complications.

BACKGROUND AND PURPOSE: Preoperative embolization for intracranial meningiomas offers potential advantages for safer and more effective surgery. However, this treatment strategy has not been examined in a large comparative series. The purpose of this study was to review our experience using preoperative embolization to understand the efficacy, technical considerations and complications of this technique. MATERIALS AND METHODS: We performed a retrospective review of patients undergoing intracranial meningioma resection at our institution (March 2001 to December 2012). Comparisons were made between embolized and nonembolized patients, including patient and tumor characteristics, embolization method, operative blood loss, complications, and extent of resection. Logistic regression analyses were used to identify factors predictive of operative blood loss and extent of resection. RESULTS: Preoperatively, 224 patients were referred for embolization, of which 177 received embolization. No complications were seen in 97.1%. There were no significant differences in operative duration, extent of resection, or complications. Estimated blood loss was higher in the embolized group (410 versus 315 mL, P=.0074), but history of embolization was not a predictor of blood loss in multivariate analysis. Independent predictors of blood loss included decreasing degree of tumor embolization (P=.037), skull base location (P=.005), and male sex (P=.034). Embolization was not an independent predictor of gross total resection. CONCLUSIONS: Preoperative embolization is a safe option for selected meningiomas. In our series, embolization did not alter the operative duration, complications, or degree of resection, but the degree of embolization was an independent predictor of decreased operative blood loss.

What are the characteristics of breast cancers misclassified as benign by quantitative ultrasound shear wave elastography?

OBJECTIVES: Shear wave elastography (SWE) is a promising adjunct to greyscale ultrasound in differentiating benign from malignant breast masses. The purpose of this study was to characterise breast cancers which are not stiff on quantitative SWE, to elucidate potential sources of error in clinical application of SWE to evaluation of breast masses. METHODS: Three hundred and two consecutive patients examined by SWE who underwent immediate surgery for breast cancer were included. Characteristics of 280 lesions with suspicious SWE values (mean stiffness >50 kPa) were compared with 22 lesions with benign SWE values (<50 kPa). Statistical significance of the differences was assessed using non-parametric goodness-of-fit tests. RESULTS: Pure ductal carcinoma in situ (DCIS) masses were more often soft on SWE than masses representing invasive breast cancer. Invasive cancers that were soft were more frequently: histological grade 1, tubular subtype, ≤10 mm invasive size and detected at screening mammography. No significant differences were found with respect to the presence of invasive lobular cancer, vascular invasion, hormone and HER-2 receptor status. Lymph node positivity was less common in soft cancers. CONCLUSION: Malignant breast masses classified as benign by quantitative SWE tend to have better prognostic features than those correctly classified as malignant. KEY POINTS: • Over 90 % of cancers assessable with ultrasound have a mean stiffness >50 kPa. • 'Soft' invasive cancers are frequently small (≤10 mm), low grade and screen-detected. • Pure DCIS masses are more often soft than invasive cancers (>40 %). • Large symptomatic masses are better evaluated with SWE than small clinically occult lesions. • When assessing small lesions, 'softness' should not raise the threshold for biopsy.

Pattern of brain metastatic disease according to HER-2 and ER receptor status in breast cancer patients.

AIMS: To document the type, location, extent, and complications of brain metastases in patients with breast cancer and identify associations with oestrogen receptor (ER) negative and human epidermal growth factor receptor 2 (HER-2) receptor expression. MATERIALS AND METHODS: Breast cancer patients with known brain metastases were included in this retrospective study, if cross-sectional imaging of the brain [computed tomography (CT)] was available to review and HER-2 and ER status was known. Two neuroradiologists, who were blinded to the receptor status, separately and for each patient, documented on a proforma the location, number, and dimensions of the deposits and the presence or absence of hydrocephalus. Adjudication was sought where there was discrepancy between the two reports. ER status, HER-2 receptor status, and patient age were also documented. The results were analysed using two-sided Fisher's exact tests with Lancaster's mid-P correction and associations were sought between the tumour characteristics and the pattern of brain disease. RESULTS: Sixty patients were included in the study. There was an association between young age (<40 years) and HER-2 positivity [10 of 24 (41.7%) versus three of 36 (8.3%); p = 0.002]. In ER-negative women, HER-2 positivity was found to be associated with a larger number (six or more) of metastases [11 of 18 (61%) versus nine of 25 (36%); p = 0.049], more brain stem metastases [11 of 18 (61%) versus three of 26 (11.5%); p = 0.035], more frequent occurrence of hydrocephalus [7 of 12 (36.8%) versus three of 26 (11.5%); p = 0.049], and a higher incidence of occipital metastases [12 of 18 (66.7%) versus eight of 26 (30.8%); p = 0.029]. CONCLUSION: ER-negative HER-2-positive women are more likely to present with a larger number of lesions, more brain stem/occipital metastases, and hydrocephalus, which may predispose them to unfavourable outcomes following treatment.

miRNA profiling in metastatic renal cell carcinoma reveals a tumour-suppressor effect for miR-215.

BACKGROUND: Renal cell carcinoma (RCC) is the most common neoplasm of the adult kidney. Metastatic RCC is difficult to treat. The 5-year survival rate for metastatic RCC is ≤10%. Recently, microRNAs (miRNAs) have been shown to have a role in cancer metastasis and potential as prognostic biomarkers in cancer. METHOD: We performed a miRNA microarray to identify a miRNA signature characteristic of metastatic compared with primary RCCs. We validated our results by quantitative real-time PCR. We performed experimental and bioinformatic analyses to explore the involvement of miR-215 in RCC progression and metastasis. RESULTS: We identified 65 miRNAs that were significantly altered in metastatic compared with primary RCCs. We validated our results by examining the expression of miR-10b, miR-126, miR-196a, miR-204 and miR-215, in two independent cohorts of patients. We showed that overexpression of miR-215 decreased cellular migration and invasion in an RCC cell line model. In addition, through gene expression profiling, we identified direct and indirect targets of miR-215 that can contribute to tumour metastasis. CONCLUSION: Our analysis showed that miRNAs are altered in metastatic RCCs and can contribute to kidney cancer metastasis through different biological processes. Dysregulated miRNAs represent potential prognostic biomarkers and may have therapeutic applications in kidney cancer.

Pathological and mammographic prognostic factors for screen detected cancers in a multi-centre randomised, controlled trial of mammographic screening in women from age 40 to 48 years.

AIM: To assess pathological and radiological prognostic factors for cancers detected by screening within a multi-centre RCT trial of mammographic screening of younger women. METHOD: The survival of 232 women with screen detected invasive cancer was ascertained. Data on invasive cancer size, histological grade, nodal status, vascular invasion, mammographic spiculation, comedo calcification and mammographic background were assessed. Kaplan-Meier and Cox proportional hazards methods were used to examine survival. RESULTS: Univariate analysis indicated that women with cancers with the following features had poorer survival; ≥ 30 mm, histologically grade 3, heavily node positive (4 or more positive nodes), vascular invasion positive and displaying mammographic comedo calcification. In a multivariate model survival remained poorer in women with four or more nodes positive (HR 8.36, 95% CI 2.31, 30.17) and in those with comedo calcification (HR 3.00,95% CI 1.13, 7.99). CONCLUSION: Nodal status and the presence of mammographic comedo calcification have independent prognostic significance in young women with screen detected cancer.

Frequency and patterns of metastatic disease in locally advanced inflammatory and non-inflammatory breast cancer.

AIMS: To determine the frequency and pattern of metastatic disease as detected by staging computed tomography in patients presenting with locally advanced primary breast cancer, comparing non-inflammatory and inflammatory subtypes. MATERIALS AND METHODS: Patients who underwent staging computed tomography for locally advanced breast cancer were identified from the hospital's computerised radiology system. The computed tomography scans, breast imaging and pathology were reviewed. RESULTS: Over a 29 month period, 97 patients underwent staging computed tomography for locally advanced primary breast cancer. Sixteen patients (16%) were found to have metastatic disease at presentation. Thirty-eight patients (39%) presented with the inflammatory subtype and 59 patients (61%) with the non-inflammatory subtype. Metastases were significantly more likely in patients with the inflammatory subtype, with 10 patients (26%) having metastases at presentation compared with six patients (10%) with the non-inflammatory subtype (P=0.034). Metastases to the lung and the pleura were the most commonly encountered sites, with pleural-based metastases more likely in patients with the inflammatory subtype (P=0.05). CONCLUSION: Routine computed tomography staging of patients with locally advanced breast cancer is worthwhile with the inflammatory subtype of locally advanced disease having the higher risk of metastatic disease at presentation. Pleural-based metastatic disease is more likely in patients with the inflammatory subtype.

Topographical analysis of telomere length and correlation with genomic instability in whole mount prostatectomies.

BACKGROUND: Many critical events in prostatic carcinogenesis appear to relate to the emergence of genomic instability. Characteristic genomic abnormalities such as 8p loss, 8q gain, trisomy 7, and PTEN microdeletions may provide selective advantages to increase neoplastic transformation. Evidence suggests that telomere dysfunction is a plausible mechanism for some of these abnormalities on the basis of the break-fusion-bridge cycle that can lead to manifestations of genomic instability. METHODS: In this study, we correlate telomere length measured by quantitative FISH in various prostatic histologies with markers of genomic instability and immunohistochemical measures of proliferation and oxidative stress. RESULTS: We find that telomere shortening is correlated with abnormalities on chromosome 8, but not with trisomy 7 or abnormalities of the PTEN locus. There are associations with C-MYC aberrations in stroma with greater proximity to cancer and a correlation between telomere length in a number of prostatic histologies and the adjacent stroma, suggesting the importance of microenvironmental effects on telomere maintenance in the prostate. This finding was also supported by the finding of the correlation between telomere attrition and the levels of oxidative stress as measured by malondialdehyde staining in HPIN lesions close to cancer. CONCLUSIONS: Telomere attrition in the prostate gland is associated with particular genomic aberrations that contribute to the genomic instability characteristic of prostatic carcinogenesis. Correlations between various histologies and adjacent stroma telomere length suggest it is also may reveal microenvironmental effects within the prostate gland. Oxidative stress may contribute to telomere attrition in HPIN close to cancer.

The efficacy of endovascular stenting in the treatment of supraclinoid internal carotid artery blister aneurysms using a stent-in-stent technique.

BACKGROUND AND PURPOSE: Blister aneurysms of the supraclinoid ICA represent a rare but well-documented cause of subarachnoid hemorrhage. These aneurysms are difficult to detect, and their surgical treatment is challenging, with high morbidity and mortality rates. The reports currently in the literature that describe the surgical and endovascular treatment of these aneurysms offer no clear consensus on the optimal treatment. We describe a staged endovascular treatment entailing stenting using a stent-in-stent technique, as well as planned but delayed embolization as the aneurysm increases in size to allow the introduction of coils. MATERIALS AND METHODS: We performed a retrospective review of all cerebral angiograms performed at our institution over an 8-month period for evaluation of subarachnoid hemorrhage, identifying 6 ICA blister aneurysms. RESULTS: All 6 blister aneurysms were located in the supraclinoid ICA. The stent-in-stent technique was used for the initial treatment of all patients. Three patients had no residual or recurrent aneurysm following initial treatment. Three patients required retreatment with coils after continued growth of the aneurysm, identified on follow-up angiography. Five patients had good recovery (average mRS score of 1), and 1 patient had poor neurologic recovery (mRS score of 3) due to a large hemorrhagic infarction. CONCLUSIONS: Our case series suggests that staged endovascular treatment entailing the use of a stent-in-stent technique, augmented with subsequent coil embolization as necessary for progressive disease, is a viable endovascular option for treating ruptured supraclinoid blister aneurysms, allowing for parent artery preservation.

Utility of CT angiography in the identification and characterization of supraclinoid internal carotid artery blister aneurysms.

BACKGROUND AND PURPOSE: Blister aneurysms of the supraclinoid ICA represent a rare but potentially catastrophic cause of SAH, often presenting both diagnostic and therapeutic dilemmas. We explore the utility of CTA in the identification and characterization of ICA blister aneurysms. MATERIALS AND METHODS: We performed a retrospective review of catheter cerebral angiograms obtained at our institution over a 12-month period for evaluation of SAH, identifying 6 cases of ICA blister aneurysms. All patients underwent CTA and DSA for evaluation of SAH. The reports from the CTA and DSA studies were reviewed to identify aneurysms correctly diagnosed prospectively. Retrospective review of the CTA and DSA images was also performed. Review of the interpretations and images was performed for any follow-up studies. RESULTS: All 6 patients presented with SAH, diagnosed by head CT. All patients subsequently underwent CTA prior to DSA evaluation. All 6 aneurysms were identified prospectively on initial DSA imaging. Of the 6 blister aneurysms, 4 (67%) were identified prospectively; and 5 (83%), retrospectively on CTA. All 6 patients underwent endovascular treatment with stent placement. Four of the 6 aneurysms underwent follow-up CTA (range, 9-22 days), including the 2 aneurysms that had been unidentifiable preprocedurally. All 4 blister aneurysms were seen postprocedurally by DSA. Three of these 4 (75%) residual aneurysms were detected by CTA (both prospectively and retrospectively). CONCLUSIONS: In the presence of SAH and otherwise negative findings on CTA, a catheter cerebral angiogram should be performed to absolutely exclude an ICA blister aneurysm.

Concurrent stenting of multiple cerebrovascular stenotic lesions: technical note.

INTRODUCTION: Until recently, the treatment of intracranial atherosclerosis has remained limited. Due to advances in endovascular technology and technique, angioplasty and stenting has become an accepted treatment for medically-refractory intracranial atherosclerosis. Patients with intracranial atherosclerosis frequently have multiple lesions, however, the clinical significance of each individual lesion is not always evident. In these instances the treating physician must decide which lesions should be managed conservatively, and which should be treated. TECHNIQUE: Emphasizing decision-making, we describe a patient in whom 3 separate atherosclerotic lesions in the same vascular territory underwent endovascular treatment in one treatment session. Each of the lesions was treated with angioplasty and stent placement. CONCLUSION: This may be a relatively safe and efficacious technique that allows for the treatment of multiple lesions without the risks associated with multiple cerebral angiograms.

Unsupervised segmentation of the prostate using MR images based on level set with a shape prior.

Prostate cancer is the second leading cause of cancer death in American men. Current prostate MRI can benefit from automated tumor localization to help guide biopsy, radiotherapy and surgical planning. An important step of automated prostate cancer localization is the segmentation of the prostate. In this paper, we propose a fully automatic method for the segmentation of the prostate. We firstly apply a deformable ellipse model to find an ellipse that best fits the prostate shape. Then, this ellipse is used to initiate the level set and constrain the level set evolution with a shape penalty term. Finally, certain post processing methods are applied to refine the prostate boundaries. We apply the proposed method to real diffusion-weighted (DWI) MRI images data to test the performance. Our results show that accurate segmentation can be obtained with the proposed method compared to human readers.