Sensitivity of magnetic resonance imaging in the detection of colorectal liver metastases

An Unusual Case of Prostate Carcinoma With Metastasis to the Iliopsoas Muscle and Nerve Root Impingement

The majority of prostate cancer cases carry a favorable prognosis due to various screening protocols and the progression of surgical/medical techniques. Prostate cancers that metastasize to the skeletal system bear worse five-year survival rates as they are indicative of widespread dissemination. There are very few cases of prostate cancer invading the iliopsoas muscle described in the medical literature. Here, we present the case of a 61-year-old male who was diagnosed with prostate cancer with metastasis to the bones and iliopsoas muscle. Given the advanced presentation of his disease, the patient underwent a prostate biopsy. He was initiated on bicalutamide and transitioned to leuprolide and docetaxel with eventual radiation therapy.

Current role of intraoperative ultrasonography in hepatectomy

Hepatectomy had a high mortality rate in the previous decade because of inadequate techniques, intraoperative blood loss, liver function reserve misdiagnoses, and accompanying postoperative complications. However, the development of several modalities, including intraoperative ultrasonography (IOUS), has made hepatectomy safer. IOUS can provide real-time information regarding the tumor position and vascular anatomy of the portal and hepatic veins. Systematic subsegmentectomy, which leads to improved patient outcomes, can be performed by IOUS in open and laparoscopic hepatectomy. Although three-dimensional (3D) computed tomography and gadoxetic acid-enhanced magnetic resonance imaging have been widely used, IOUS and contrast-enhanced IOUS are important modalities for risk analyses and making decisions regarding resectability and operative procedures because of the vital anatomical information provided and high sensitivity for liver tumors, including "disappearing" liver metastases. Intraoperative color Doppler ultrasonography can be used to delineate the vascular anatomy and evaluate the blood flow volume and velocity in hepatectomy patients and recipients of deceased- and living-donor liver transplantation after vessel reconstruction and liver positioning. For liver surgeons, IOUS is an essential technique to perform highly curative hepatectomy safely, although recent advances have also been made in virtual modalities, such as real-time virtual sonography with 3D visualization.

Prognostic value of incidental hypervascular micronodules detected on cone-beam computed tomography angiography of patients with liver metastasis

PURPOSE

To determine the clinical relevance of incidentally-found hypervascular micronodules (IHM) on cone-beam computed tomography angiography (CBCTA) in patients with liver metastasis undergoing transarterial (chemo)embolization (TACE/TAE).

MATERIAL AND METHODS

This was a HIPAA-compliant institutional review board-approved single-institution retrospective review of 95 non-cirrhotic patients (52 men; mean age, 60 years) who underwent CBCTA prior to (chemo)embolic delivery. IHM were defined by the presence of innumerable subcentimetre hepatic parenchymal hypevascular foci not detected on pre-TACE/TAE contrast-enhanced cross-sectional imaging. Multivariate analysis was performed to compare time to tumour progression (TTP) between patients with and without IHM.

RESULTS

IHM were present in 21 (22%) patients. Patients with IHM had a significantly shorter intrahepatic TTP determined by a higher frequency of developing new liver metastasis (hazard ratio [HR]: 1.99; 95% confidence interval [CI] 1.08-3.67, P= 0.02). Patients with IHM trended towards a shorter TTP of the tumour(s) treated with TACE/TAE (HR: 1.72; 95% CI: 0.98-3.01, P= 0.056). Extrahepatic TTP was not significantly different between the two cohorts (P= 0.27).

CONCLUSION

Patients with IHM on CBCTA have worse prognosis due to a significantly higher risk of developing new hepatic tumours. Further work is needed to elucidate its underlying mechanisms of pathogenesis.

KEY POINTS

• 21% of liver metastasis patients undergoing TACE/TAE have IHM on CBTA. • IHM are associated with a high risk of developing new hepatic tumours. • IHA are also associated with a trend toward poorer response to TACE/TAE.

Future of the Renal Biopsy: Time to Change the Conventional Modality Using Nanotechnology

At the present time, imaging guided renal biopsy is used to provide diagnoses in most types of primary and secondary renal diseases. It has been claimed that renal biopsy can provide a link between diagnosis of renal disease and its pathological conditions. However, sometimes there is a considerable mismatch between patient renal outcome and pathological findings in renal biopsy. This is the time to address some new diagnostic methods to resolve the insufficiency of conventional percutaneous guided renal biopsy. Nanotechnology is still in its infancy in renal imaging; however, it seems that it is the next step in renal biopsy, providing solutions to the limitations of conventional modalities.

Unexpected Angiography Findings and Effects on Management

Despite progress in noninvasive imaging with computed tomography and magnetic resonance imaging, conventional angiography still contributes to the diagnostic workup of oncologic and other diseases. Arteriography can reveal tumors not evident on cross-sectional imaging, in addition to defining aberrant or unexpected arterial supply to targeted lesions. This additional and potentially unanticipated information can alter management decisions during interventional procedures.

Measurements of Hepatic Metastasis on MR Imaging:: Assessment of Interobserver and Intersequence Variability

RATIONALE AND OBJECTIVES

The purpose of the study was to investigate interobserver and intersequence variability in the measurement of hepatic metastasis on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

This retrospective study was conducted with an institutional review board-approved waiver of informed consent and was in compliance with the Health Insurance Portability and Accountability Act. We searched medical records at our institution for patients with histologically proven metastases to the liver who had undergone MRI from January 2008 to June 2010. We identified 20 patients with 30 measurable liver lesions. The liver lesions were measured on five different MRI sequences. A presenter radiologist selected and localized all metastatic lesions considered to be measurable according to the Response Evaluation Criteria in Solid Tumors, and these lesions were measured (Eisenhauer et al., 2009) by three radiologists independently. We calculated lesion-wise intraclass correlation coefficients (ICCs) to estimate interobserver and intersequence agreement in lesion diameter measurement. A Bland-Altman plot was used to estimate the limits of agreement between radiologists and MRI sequences.

RESULTS

There were 30 metastases, and almost all of which had regular and well-defined margins. Interobserver ICCs were greater than 0.95 for different MRI sequences except for the measurements in apparent diffusion coefficient images. Intersequence ICCs were greater than 0.92. Bland-Altman plots between physicians confirmed that reader measurements were closely tied together, with small differences in means.

CONCLUSIONS

MRI can reproducibly measure hepatic metastatic lesions without significant variability among interpreting radiologists or among MRI sequences, and is thus a reliable method for assessing the size of hepatic metastasis.

Non-invasive diagnostic imaging of colorectal liver metastases

Colorectal cancer is one of the few malignant tumors in which synchronous or metachronous liver metastases [colorectal liver metastases (CRLMs)] may be treated with surgery. It has been demonstrated that resection of CRLMs improves the long-term prognosis. On the other hand, patients with un-resectable CRLMs may benefit from chemotherapy alone or in addition to liver-directed therapies. The choice of the most appropriate therapeutic management of CRLMs depends mostly on the diagnostic imaging. Nowadays, multiple non-invasive imaging modalities are available and those have a pivotal role in the workup of patients with CRLMs. Although extensive research has been performed with regards to the diagnostic performance of ultrasonography, computed tomography, positron emission tomography and magnetic resonance for the detection of CRLMs, the optimal imaging strategies for staging and follow up are still to be established. This largely due to the progressive technological and pharmacological advances which are constantly improving the accuracy of each imaging modality. This review describes the non-invasive imaging approaches of CRLMs reporting the technical features, the clinical indications, the advantages and the potential limitations of each modality, as well as including some information on the development of new imaging modalities, the role of new contrast media and the feasibility of using parametric image analysis as diagnostic marker of presence of CRLMs.

Usefulness of intraoperative ultrasonography in liver resections due to colon cancer metastasis

INTRODUCTION

Intraoperative ultrasonography (IOUS) of the liver has been used both as an aid for intraoperative anatomical definition and for the detection of new lesions. The present study aimed to evaluate the impact of IOUS and to identify factors that can predict the detection of new lesions intraoperatively.

METHODS

In this observational and prospective study, with a cross-sectional design, patients with colorectal cancer metastases who underwent hepatectomy were selected. Abdominal computed tomography, magnetic resonance imaging, and positron emission tomography were the preoperative evaluation tests. All patients underwent IOUS performed by the same surgeon. The intraoperative findings were compared with the preoperative tests results.

RESULTS

In total, 56 hepatectomies were evaluated. Half of the patients were men, with a mean age of 57 (30-85) years. New lesions were found intraoperatively in 12 patients (21.4% of cases) and were detected on both palpation and ultrasonography in 11 of these patients. Ultrasonography helped to revise the surgical plans by providing additional information in 35.7% of cases. On multivariate analysis, the presence of more than 4 preoperative nodules was predictive of the intraoperative occurrence of new lesions.

CONCLUSIONS

IOUS remains the only way to evaluate the relationships between tumors, liver vascular structures, and bile ducts intraoperatively. Alone, IOUS was not useful for identifying new lesions intraoperatively, as all new lesions were also detected on palpation. The number of lesions diagnosed on preoperative tests influenced the probability of identifying new lesions intraoperatively. There may be additional influential factors.

Recurrence and metastasis of lung cancer demonstrate decreased diffusion on diffusion-weighted magnetic resonance imaging

BACKGROUND

Diffusion-weighted magnetic resonance imaging (DWI) is reported to be useful for detecting malignant lesions. The purpose of this study is to clarify characteristics of imaging, detection rate and sensitivity of DWI for recurrence or metastasis of lung cancer.

METHODS

A total of 36 lung cancer patients with recurrence or metastasis were enrolled in this study. While 16 patients underwent magnetic resonance imaging (MRI), computed tomography (CT) and positron emission tomography-computed tomography (PET-CT), 17 underwent MRI and CT, and 3 underwent MRI and PET-CT.

RESULTS

Each recurrence or metastasis showed decreased diffusion, which was easily recognized in DWI. The detection rate for recurrence or metastasis was 100% (36/36) in DWI, 89% (17/19) in PET-CT and 82% (27/33) in CT. Detection rate of DWI was significantly higher than that of CT (p=0.0244) but not significantly higher than that of PET-CT (p=0.22). When the optimal cutoff value of the apparent diffusion coefficient value was set as 1.70?10-3 mm2/sec, the sensitivity of DWI for diagnosing recurrence or metastasis of lung cancer was 95.6%.

CONCLUSIONS

DWI is useful for detection of recurrence and metastasis of lung cancer.

Feasibility for detecting liver metastases in dogs using gadobenate dimeglumine-enhanced magnetic resonance imaging

Early detection of liver metastases may improve the prognosis for successful treatment in dogs with primary tumors. Hepatobiliary-specific contrast agents have been shown to allow an increase in magnetic resonance imaging (MRI) detection of liver metastases in humans. The purpose of this prospective study was to test the feasibility for using one of these agents, gadobenate dimeglumine, to detect liver metastases in dogs. Ten consecutive dogs known to have a primary tumor were recruited for inclusion in the study. All dogs were scanned using the same protocol that included a T2-weighted respiratory-triggered sequence, T1 VIBE, diffusion-weighted imaging, and 3D-FLASH before and after dynamic injection of gadobenate dimeglumine contrast medium. Delayed imaging was performed less than 30 min after injection and up to 60 min in two cases. Histological analysis of liver lesions identified in delayed phases was performed for each case and confirmed metastatic origin. In all cases, lesion number detected in hepatobiliary contrast-enhanced sequences was statistically higher than in other sequences. Optimal lesion detection occurred with a 3D-FLASH sequence acquired in the transverse plane and less than 30 min after injection. Findings indicated that gabobenate dimeglumine enhanced MRI is a feasible technique for detecting liver metastases in dogs.

Liver metastases: Contrast-enhanced ultrasound compared with computed tomography and magnetic resonance

The development of ultrasound contrast agents with excellent tolerance and safety profiles has notably improved liver evaluation with ultrasound (US) for several applications, especially for the detection of metastases. In particular, contrast enhanced ultrasonography (CEUS) allows the display of the parenchymal microvasculature, enabling the study and visualization of the enhancement patterns of liver lesions in real time and in a continuous manner in all vascular phases, which is similar to contrast-enhanced computed tomography (CT) and contrast-enhanced magnetic resonance imaging. Clinical studies have reported that the use of a contrast agent enables the visualization of more metastases with significantly improved sensitivity and specificity compared to baseline-US. Furthermore, studies have shown that CEUS yields sensitivities comparable to CT. In this review, we describe the state of the art of CEUS for detecting colorectal liver metastases, the imaging features, the literature reports of metastases in CEUS as well as its technique, its clinical role and its potential applications. Additionally, the updated international consensus panel guidelines are reported in this review with the inherent limitations of this technique and best practice experiences.

A comparison of diagnostic imaging modalities for colorectal liver metastases

AIMS

The aims of this study were to compare the diagnostic performance of CT scan, MR liver, PET-CT and intra-operative ultrasound (IOUS) for the detection of liver metastases against the histopathological findings, and to compare PET-CT with CT for the detection of distant disease in metastatic colorectal cancer patients eligible for surgical treatment.

METHODS

A prospective study was performed that measured concordance between the number and stage of metastatic lesions identified with various preoperative imaging modalities and histology of patients undergoing surgical treatment for CRLM.

RESULTS

Compared with histopathology, concordance for the number of metastatic liver lesions was moderate for CT scan (K = 0.477, 95% CI: 0.28-0.66), moderate for MR scan (K = 0.574, 95% CI: 0.39-0.75), good for FDG PET-CT (K = 0.703, 95% CI: 0.52-0.87) and very good for IOUS (K = 0.904, 95% CI: 0.81-0.99). Additional CRLM were identified intraoperatively in six patients (9.1%) with IOUS and in 7.5% of the cases surgical strategy was changed according to the new intraoperative findings. The diagnosis of intra abdominal lymph node metastatic disease was made with PET-CT only in nine patients (13.6%)

DISCUSSION

Our study supports the recent recommendations of the Oncosurg Multidisciplinary International Consensus regarding the importance of high quality CT and MR in the staging of CRLM but provides further evidence for the added value of PET-CT, especially in detecting extrahepatic intra-abdominal metastatic disease that may be amenable to potentially curative resection. Despite these advances in preoperative staging, there still remains a role for IOUS in detecting additional metastases at the time of surgery.

Targeted imaging of Ewing sarcoma in preclinical models using a 64Cu-labeled anti-CD99 antibody

PURPOSE

Ewing sarcoma is a tumor of the bone and soft tissue characterized by diffuse cell membrane expression of CD99 (MIC2). Single-site, surgically resectable disease is associated with an excellent 5-year event-free survival; conversely, patients with distant metastases have a poor prognosis. Noninvasive imaging is the standard approach to identifying sites of metastatic disease. We sought to develop a CD99-targeted imaging agent for staging Ewing sarcoma and other CD99-expressing tumors.

EXPERIMENTAL DESIGN

We identified a CD99 antibody with highly specific binding in vitro and labeled this antibody with (64)Cu. Mice with either subcutaneous Ewing sarcoma xenograft tumors or micrometastases were imaged with the (64)Cu-labeled anti-CD99 antibody and these results were compared with conventional MRI and 2[18F]fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) imaging.

RESULTS

(64)Cu-labeled anti-CD99 antibody demonstrated high avidity for the CD99-positive subcutaneous tumors, with a high tumor-to-background ratio, greater than that demonstrated with FDG-PET. Micrometastases, measuring 1 to 2 mm on MRI, were not detected with FDG-PET but were readily visualized with the (64)Cu-labeled anti-CD99 antibody. Probe biodistribution studies demonstrated high specificity of the probe for CD99-positive tumors.

CONCLUSIONS

(64)Cu-labeled anti-CD99 antibody can detect subcutaneous Ewing sarcoma tumors and metastatic sites with high sensitivity, outperforming FDG-PET in preclinical studies. This targeted radiotracer may have important implications for the diagnosis, surveillance, and treatment of Ewing sarcoma. Similarly, it may impact the management of other CD99 positive tumors.

The Preoperative Assessment of Hepatic Tumours: Evaluation of UK Regional Multidisciplinary Team Performance

Introduction. In the UK, patients where liver resection is contemplated are discussed at hepatobiliary multidisciplinary team (MDT) meetings. The aim was to assess MDT performance by identification of patients where radiological and pathological diagnoses differed. Materials and Methods. A retrospective review of a prospectively maintained database of all cases undergoing liver resection from March 2006 to January 2012 was performed. The presumed diagnosis as a result of radiological investigation and MDT discussion is recorded at the time of surgery. Imaging was reviewed by specialist gastrointestinal radiologists, and resultswereagreedonby consensus. Results. Four hundred and thirty-eight patients were studied. There was a significant increase in the use of preoperative imaging modalities (P ≤ 0.01) but no change in the rate of discrepant diagnosis over time. Forty-two individuals were identified whose final histological diagnosis was different to that following MDT discussion (9.6%). These included 30% of patients diagnosed preoperatively with hepatocellular carcinoma and 25% with cholangiocarcinoma of a major duct. Discussion. MDT assessment of patients preoperatively is accurate in terms of diagnosis. The highest rate of discrepancies occurred in patients with focal lesions without chronic liver disease or primary cancer, where hepatocellular carcinoma was overdiagnosed and peripheral cholangiocarcinoma underdiagnosed, where particular care should be taken. Additional care should be taken in these groups and preoperative multimodality imaging considered.

Manejo atual das metástases hepáticas de câncer colorretal: recomendações do Clube do Fígado de São Paulo

Aproximadamente metade dos pacientes portadores de câncer colorretal apresenta metástases hepáticas durante a evolução de sua doença que afetam diretamente o prognóstico e são diretamente responsáveis por 2/3 dos óbitos relacionados à doença. Nas últimas duas décadas o tratamento das metástases hepáticas de câncer colorretal (MHCCR) proporcionou ganho expressivo na sobrevida quando todas as opções terapêuticas são colocadas à disposição do paciente. Nesse contexto, o tratamento cirúrgico persiste como a única possibilidade de cura com índices de sobrevida em cinco anos de 25 a 58%. No entanto, apenas 1/4 dos pacientes tem doença ressecável ao diagnóstico. Por essa razão, um dos pontos fundamentais no manejo atual dos pacientes com MHCCR é o desenvolvimento de estratégias que possibilitem a ressecção completa das lesões hepáticas. O advento e aperfeiçoamento dos métodos ablativos expandiram as possibilidades da terapêutica cirúrgica, além disto, o surgimento de novos esquemas quimioterápicos e a introdução das terapias-alvo proporcionou altas taxas de resposta e alteraram definitivamente o manejo destes pacientes. O tratamento multimodal e a utilização da experiência de diversas especialidades médicas permitiram que o tratamento das MHCCR se aproximasse cada vez mais do tratamento ideal, ou seja, individualizado. Baseado em uma extensa revisão da literatura e na experiência de alguns dos centros especializados mais importantes do Brasil, o Clube do Fígado de São Paulo iniciou um trabalho de discussão multi-institucional que resultou nas recomendações que se seguem. Essas recomendações, no entanto, não visam ser absolutas, mas sim ferramentas úteis no processo de decisão terapêutica desse grupo complexo de pacientes.

Preoperative evaluation of colorectal liver metastases: comparison between gadoxetic acid-enhanced 3.0-T MRI and contrast-enhanced MDCT with histopathological correlation

OBJECTIVES

The aim of this prospective study was to compare the diagnostic performance of 64-row MDCT and gadoxetic-acid-enhanced MRI at 3.0 T in patients with colorectal liver metastases in correlation with histopathological findings.

METHODS

Lesions detected at MDCT and MRI were interpreted by three blinded readers and compared with histopathological workup as the term of reference. Two subgroups of lesions were additionally evaluated: (1) metastases smaller than 10 mm and (2) lesions in patients with and without steatosis of the liver, assessed histopathologically.

RESULTS

Surgery and histopathological workup revealed 81 colorectal liver metastases in 35 patients and diffuse metastatic involvement in 3 patients. In a lesion-by-lesion analysis, significant sensitivity differences could only be found for reader 1 (P = 0.035) and reader 3 (P = 0.003). For segment-based evaluation, MRI was more sensitive only for reader 3 (P = 0.012). The number of false-positive results ranged from 3 to 12 for MDCT and 8 to 11 for MRI evaluation. In the group of small lesions, the sensitivity differed significantly between both methods (P = 0.003). In patients with hepatic steatosis, MRI showed a trend toward better performance than MDCT, but without statistical performance.

CONCLUSIONS

The 3.0-T MRI with liver-specific contrast agents is the preferred investigation in the preoperative setting, especially for the assessment of small colorectal liver metastases.

KEY POINTS

• Potential surgical treatment requires accurate radiological assessment of colorectal liver metastases • Magnetic resonance imaging with gadoxetic acid is the preferred imaging investigation. • MRI is better than multidetector CT for detecting small liver metastases.

Simultaneous surgery for primary colorectal cancer and metastatic lesions?

Approximately 20-25% of patients with colorectal cancer present with liver metastases at the time of diagnosis. Traditionally, resection of the primary tumor has been advocated in order to prevent complications of the primary tumor colorectal cancer in patients with synchronous liver metastases. The published data concerning long-term prognosis in this group of patients are discordant. Although some of the reports show survival benefits from resection of the primary tumor, these studies are retrospective with small number of patients and using single drug chemotherapy. For patients with resectable liver metastases, new studies indicate that progression-free survival is best in patients receiving perioperative chemotherapy. In patients with synchronous nonresectable liver metastases and colorectal cancer, there is no published prospective randomized study comparing initial surgery of the primary tumor with neoadjuvant chemotherapy. However, recent publications show that in patients receiving chemotherapy based on oxaliplatin or irinotecan combined with targeted treatments, the complications associated with the primary tumor are less than 10%. The conclusion should be that today prophylactic surgery of asymptomatic primary colorectal cancer in patients with liver metastases cannot be recommended.

Visualisation of liver tumours using hand-held real-time strain imaging: results of animal experiments

OBJECTIVE

Surgical resection is the only curative option for colorectal hepatic metastases. Intra-operative localisation of these metastases during hepatic resection is performed by intra-operative B-mode imaging and palpation. Because liver metastases are stiffer than normal tissues, elastography may be a useful complement to B-mode imaging. This paper reports quantitative measures of the image quality attained during intra-operative real-time elastographic visualisation of liver metastasis.

METHODS

VX2 tumours were implanted in the liver of eight rabbits and were scanned in vivo. Measurements of the tumour dimensions obtained via elastography were compared with those obtained using B-mode imaging and with gross pathology.

RESULTS

Measurements of tumour diameters were similar when obtained by intra-operative elastography and pathological measurement methods (mean difference±standard deviation, 0.1±0.9 mm). The contrast between tumours and normal tissues was significantly higher (p<0.05) in elastograms (26±10 dB contrast) than in sonograms (1±1 dB contrast). Sensitivity and specificity for detecting tumours using intra-operative elastography were 100% and 88%, respectively, and positive and negative predictive values were 89% and 100%, respectively. In two cases elastograms were able to detect a tumour that was ambiguous in B-mode images.

CONCLUSION

Combined hand-held B-mode/strain imaging may provide additional information that is relevant for detection of liver metastases that may be missed by standard B-mode imaging alone, such as small and/or isoechoic tumours.

Is neoadjuvant chemotherapy necessary for patients with initially resectable colorectal liver metastases in the era of effective chemotherapy?

Backgrounds/Aims

Hepatic resection has only guaranteed long-term survival in patients with colorectal liver metastasis (CRLM) even in the era of effective chemotherapy. The definite role of neoadjuvant chemotherapy (NCT) is to improve outcomes of unresectable CRLMs, but it its role has not been defined for initially resectable CRLMs (IR-CRLMs).

Methods

We reviewed the medical records of 226 patients, who had been diagnosed and treated for IR-CRLM between 2003 and 2008; the patients had the following pathologies: 10% had more than 4 nodules, 11% had tumors larger than 5 cm, and 61% had synchronous CRMLs. Among these patients, 20 patients (Group Y) were treated with NCT, and 206 (Group N) did not receive NCT according to their physician's preference. The median follow-up time was 34.1 months.

Results

The initial surgical plans were changed after NCT to further resection in 20% and to limited resection in 10% of 20 patients. Complication rates of Groups Y (30%) were indifferent from Group N (23%) (p=0.233), but intraoperative transfusions were more frequent in Group N (15%) than in Group Y (5%) (p=0.006). There was one case of hospital mortality (0.44%). Disease-free survival rates in Groups Y and N were 23% and 39%, respectively, and patient survival rates were 42% and 66% (p>0.05). By multivariate analysis, old age (≥60 years), differentiation of primary tumor (poorly/mucinous), resection margin involvement, and no adjuvant chemotherapy were associated with poor patient survival; the number of CRLMs (≥4) was associated with poor disease-free survival.

Conclusions

NCT had neither a positive impact nor a negative impact on survival, even with intraoperative transfusion, as observed on operative outcomes for patients with IR-CRLM. Further study is required to elucidate the role of NCT for treatment of patient with IR-CRLMs.

Imaging diagnosis of colorectal liver metastases

Rapid advances in imaging technology have improved the detection, characterization and staging of colorectal liver metastases. Multi-modality imaging approach is usually the more useful in diagnosis colorectal liver metastases. It is well established that hepatic resection improves the long-term prognosis of many patients with liver metastases. However, incomplete resection does not prolong survival, so knowledge of the exact extent of intra-hepatic disease is crucially important in determining patient management and outcome. The diagnosis of liver metastases relies first and totally on imaging to decide which patients may be surgical candidates. This review will discuss the imaging options and their appropriate indications. Imaging and evaluating of colorectal liver metastases (CRLM) have been performed with contrast-enhanced ultrasound, multi-detector computed tomography, magnetic resonance imaging (MRI) with extra-cellular contrast media and liver-specific contrast media MRI, and positron emission tomography/computed tomography. This review will concentrate on the imaging approach of CRLM, and also discuss certain characteristics of some liver lesions. We aim to highlight the advantages of each imaging technique, as well as underscoring potential pitfalls and limitations.

Vascular profile characterization of liver tumors by magnetic resonance imaging using hemodynamic response imaging in mice

Recently, we have demonstrated the feasibility of using hemodynamic response imaging (HRI), a functional magnetic resonance imaging (MRI) method combined with hypercapnia and hyperoxia, for monitoring vascular changes during liver pathologies without the need of contrast material. In this study, we evaluated HRI ability to assess changes in liver tumor vasculature during tumor establishment, progression, and antiangiogenic therapy. Colorectal adenocarcinoma cells were injected intrasplenically to model colorectal liver metastasis (CRLM) and the Mdr2 knockout mice were used to model primary hepatic tumors. Hepatic perfusion parameters were evaluated using the HRI protocol and were compared with contrast-enhanced (CE) MRI. The hypovascularity and the increased arterial blood supply in well-defined CRLM were demonstrated by HRI. In CRLM-bearing mice, the entire liver perfusion was attenuated as the HRI maps were significantly reduced by 35%. This study demonstrates that the HRI method showed enhanced sensitivity for small CRLM (1-2 mm) detection compared with CE-MRI (82% versus 38%, respectively). In addition, HRI could demonstrate the vasculature alteration during CRLM progression (arborized vessels), which was further confirmed by histology. Moreover, HRI revealed the vascular changes induced by rapamycin treatment. Finally, HRI facilitates primary hepatic tumor characterization with good correlation to the pathologic differentiation. The HRI method is highly sensitive to subtle hemodynamic changes induced by CRLM and, hence, can function as an imaging tool for understanding the hemodynamic changes occurring during CRLM establishment, progression, and antiangiogenic treatment. In addition, this method facilitated the differentiation between different types of hepatic lesions based on their vascular profile noninvasively.

A Lower-Cost High-Resolution LYSO Detector Development for Positron Emission Mammography (PEM)

In photomultiplier-quadrant-sharing (PQS) geometry for positron emission tomography applications, each PMT is shared by four blocks and each detector block is optically coupled to four round PMTs. Although this design reduces the cost of high-resolution PET systems, when the camera consists of detector panels that are made up of square blocks, half of the PMT's sensitive window remains unused at the detector panel edge. Our goal was to develop a LYSO detector panel which minimizes the unused portion of the PMTs for a low-cost, high-resolution, and high-sensitivity positron emission mammography (PEM) camera. We modified the PQS design by using elongated blocks at panel edges and square blocks in the inner area. For elongated blocks, symmetric and asymmetrical reflector patterns were developed and PQS and PMT-half-sharing (PHS) arrangements were implemented in order to obtain a suitable decoding. The packing fraction was 96.3% for asymmetric block and 95.5% for symmetric block. Both of the blocks have excellent decoding capability with all crystals clearly identified, 156 for asymmetric and 144 for symmetric and peak-to-valley ratio of 3.0 and 2.3 respectively. The average energy resolution was 14.2% for the asymmetric block and 13.1% for the symmetric block. Using a modified PQS geometry and asymmetric block design, we reduced the unused PMT region at detector panel edges, thereby increased the field-of-view and the overall detection sensitivity and minimized the undetected breast region near the chest wall. This detector design and using regular round PMT allowed building a lower-cost, high-resolution and high-sensitivity PEM camera.