Advances in computed tomography and magnetic resonance imaging of hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is the most common primary liver cancer.Imaging is important for establishing a diagnosis of HCC and early diagnosis is imperative as several potentially curative treatments are available when HCC is small.Hepatocarcinogenesis occurs in a stepwise manner on a background of chronic liver disease or cirrhosis wherein multiple genes are altered resulting in a range of cirrhosisassociated nodules.This progression is related to increased cellularity,neovascularity and size of the nodule.An understanding of the stepwise progression may aid in early diagnosis.Dynamic and multiphase contrast-enhanced computed tomography and magnetic resonance imaging still form the cornerstone in the diagnosis of HCC.An overview of the current diagnostic standards of HCC in accordance to the more common practicing guidelines and their differences will be reviewed.Ancillary features contribute to diagnostic confidence and has been incorporated into the more recent Liver Imaging Reporting and Data System.The use of hepatocyte-specific contrast agents is increasing and gradually changing the standard of diagnosis of HCC;the most significant benefit being the lack of uptake in the hepatocyte phase in the earlier stages of HCC progression.An outline of supplementary techniques in the imaging of HCC will also be reviewed.

Differential diagnosis of benign and malignant branch duct intraductal papillary mucinous neoplasm using contrastenhanced endoscopic ultrasonography

AIM: To elucidate the role of contrast-enhanced endoscopic ultrasonography(CE-EUS) in the diagnosis of branch duct intraductal papillary mucinous neoplasm(BD-IPMN).METHODS: A total of 50 patients diagnosed with BDIPMN by computed tomography(CT) and endoscopic ultrasonography(EUS) at our institute were included in this study. CE-EUS was performed when mural lesions were detected by EUS. The diagnostic accuracy for identifying mural nodules(MNs) was evaluated by CT, EUS, and EUS combined with CE-EUS. In the patients who underwent resection, the accuracy of measuring MN height with each imaging modality was compared. The cut-off values to diagnose malignant BD-IPMNs based on MN height for each imaging modality were determined using receiver operating characteristic curve analysis.RESULTS: Fifteen patients were diagnosed with BD-IPMN with MNs and underwent resection. The remaining 35 patients were diagnosed with BD-IPMN without MNs and underwent follow-up monitoring. The pathological findings revealed 14 cases with MNs and one case without. The accuracy for diagnosing MNs was 92% using CT and 72% using EUS; the diagnostic accuracy increased to 98% when EUS and CE-EUS were combined. The accuracy for measuring MN height significantly improved when using CE-EUS compared with using CT or EUS(median measurement error value, CT: 3.3 mm vs CE-EUS: 0.6 mm, P < 0.05; EUS: 2.1 mm vs CE-EUS: 0.6 mm, P < 0.01). A cut-off value of 8.8 mm for MN height as measured by CE-EUS improved the accuracy of diagnosing malignant BDIPMN to 93%. CONCLUSION: Using CE-EUS to measure MN height provides a highly accurate method for differentiating benign from malignant BD-IPMN.

Mesenteric panniculitis: Various presentations and treatment regimens

Mesenteric panniculitis is a rare, benign and chronic f ibrosing inflammatory disease that affects the adipose tissue of the mesentery of the small intestine and colon. The specific etiology of the disease is unknown. The diagnosis is suggested by computed tomography and is usually confirmed by surgical biopsies. Treatment is empirical and based on a few selected drugs. Surgical resection is sometimes attempted for def initive therapy, although the surgical approach is often limited. We report two cases of mesenteric panniculitis with two different presentations and subsequently varying treatment regimens. Adequate response was obtained in both patients. We present details of these cases as well as a literature review to compare various presentations, etiologies and potential treatment modalities.

Acute appendicitis following endoscopic mucosal resection of cecal adenoma

Endoscopic mucosal resection(EMR) allows the removal of flat or sessile lesions, laterally spreading tumors, and carcinoma of the colon or the rectum limited to the mucosa or the superficial submucosa. Acute appendicitis is the most common abdominal emergency requiring emergency surgery, and it is also a rare complication of diagnostic colonoscopy and therapeutic endoscopy, including EMR. In the case presented here, a 53-year-old female underwent colonoscopy due to a positive fecal occult blood test and was diagnosed with cecal adenoma. She was referred to our hospital and admitted for treatment. The patient had no other symptoms. EMR was performed, and 7 h after the surgery, the patient experienced right-lower abdominal pain. Laboratory tests performed the following day revealed a WBC count of 16000/mm3, a neutrophil count of 14144/mm3, and a C-reactive protein level of 2.20 mg/d L, indicating an inflammatory response. Computed tomography also revealed appendiceal wall thickening and swelling, so acute appendicitis following EMR was diagnosed. Antibiotics were initiated leading to total resolution of the symptoms, and the patient was discharged on the sixth post-operative day. Pathological analysis revealed a high-grade cecal tubular adenoma. Such acute appendicitis following EMR is extremely rare, and EMR of the cecum may be a rare cause of acute appendicitis.

Prediction of liver cirrhosis, using diagnostic imaging tools

Early diagnosis of liver cirrhosis is important. Ultrasoundguided liver biopsy is the gold standard for diagnosis of liver cirrhosis. However, its invasiveness and sampling bias limit the applicability of the method. Basic imaging for the diagnosis of liver cirrhosis has developed over the last few decades, enabling early detection of morphological changes of the liver by ultrasonography(US), computed tomography, and magnetic resonance imaging(MRI). They are also accurate diagnostic methods for advanced liver cirrhosis, for which early diagnosis is difficult. There are a number of ways to compensate for this difficulty, including texture analysis to more closely identify the homogeneity of hepatic parenchyma, elastography to measure the stiffness and elasticity of the liver, and perfusion studies to determine the blood flow volume, transit time, and velocity. Amongst these methods, elastography using US and MRI was found to be slightly easier, faster, and able to provide an accurate diagnosis. Early diagnosis of liver cirrhosis using MRI or US elastography is therefore a realistic alternative, but further research is still needed.

Current status of low dose multi-detector CT in the urinary tract

Over the past several years,advances in the technical domain of computed tomography(CT) have influenced the trend of imaging modalities used in the clinical evaluation of the urinary system.Renal collecting systems can be illustrated more precisely with the advent of multi-detector row CT through thinner slices,high speed acquisitions,and enhanced longitudinal spatial resolution resulting in improved reformatted coronal images.On the other hand,a significant increase in exposure to ionizing radiation,especially in the radiosensitive organs,such as the gonads,is a concern with the increased utilization of urinary tract CT.In this article,we discuss the strategies and techniques availablefor reducing radiation dose for a variety of urinary tractCT protocols with metabolic clinical examples.We also reviewed CT for hematuria evaluation and related scan parameter optimization such as,reducing the number of acquisition phases,CT angiography of renal donors and lowering tube potential,when possible.

Effect of Acupuncture Signal after Brachial Plexus Blockade on Cerebral Blood Perfusion and Brain Cell Function

Objective: Using single photon emission computed tomography (SPECT) to observe the influence of the up-transmitting of acupuncture signal into the brain in health volunteers whose nerve trunk was blocked by anesthetics. Methods: Thirty-one healthy volunteers were divided into two groups, the control group of 20 cases, and the brachial plexus blockade (BPB) group of 11 cases, with supraclavicular BPB route adopted. With the control group 2 acupoints were randomly selected (Hegu and Quchi of both sides), while with the BPB group Hegu and Quchi of anesthetic arm side were selected. Siemens ECAM/ ICON SPECT system was used to conduct brain imaging using double imaging assay before acupuncture and 99mTc-ECD imaging agent during acupuncture for cerebral perfusion. The data were quantitatively analyzed by blood functional changing rate (BFCR%) mathematics model. Results: Before acupuncture, the control and BPB groups showed insignificant change by SPECT, but after electro-acupuncture (EA), the control group displayed improved motor and sensory cortex excitability in basal nuclei, contra-lateral thal-amus, parietal and frontal lobe; while BPB group was characterized with reduction of the blood perfusion and cell function of contra-lateral thalamus of anesthetized arm. The difference between the two groups was significant (P<0.01) . Conclusion: (1) After BPB, the up-transmitting of the acupuncture signal via upper limb into the brain, and its strength was impaired or blocked; (2) After BPB, the effect of acupuncture on cerebral perfusion and brain cell function of contra-lateral thalamus was impaired or blocked.

Value of CT-guided core-needle biopsy in diagnosis and classification of malignant lymphomas using automated biopsy gun

AIM: To evaluate the value of CT-guided core-needle biopsy in diagnosis and classification of malignant lymphomas.METHODS: From January 1999 to October 2004, CT-guided core-needle biopsies were performed in 80 patients with suspected malignant lymphoma. Biopsies were performed with an 18-20 G biopsy-cut (CR Bard, Inc., Covington, GA,USA) needle driven by a spring-loaded Bard biopsy gun.RESULTS: A definite diagnosis and accurate histological subtype were obtained in 61 patients with a success rate of 76.25% (61/80). Surgical sampling was performed in 19 patients (23.75%) with non-diagnostic core-needle biopsies. The success rate of CT-guided core-needle biopsy varied with the histopathologic subtypes in our group.The relatively high success rates of core-needle biopsy were noted in diffuse large B-cell non-Hodgkin's lymphoma (NHL, 88.89%) and peripheral T-cell NHL (90%). However,the success rates were relatively low in anaplastic large cell (T/null cell) lymphoma (ALCL, 44.44%) and Hodgkin's disease (HD, 28.57%) in our group.CONCLUSION: CT-guided core-needle biopsy is a reliable means of diagnosing and classifying malignant lymphomas,and can be widely applied in the management of patients with suspected malignant lymphoma.

Hepatic portal venous gas after endoscopy in a patient with anastomotic obstruction

A 72-year-old male underwent a laparoscopic low anterior resection for advanced rectal cancer.A diverting loop ileostomy was constructed due to an anastomotic leak five days postoperatively.Nine months later,colonoscopy performed through the stoma showed complete anastomotic obstruction.The mucosa of the proximal sigmoid colon was atrophic and whitish.Ten days after the colonoscopy,the patient presented in shock with abdominal pain.Abdominal computed tomography scan showed hepatic portal venous gas(HPVG) and a dilated left colon.HPVG induced by obstructive colitis was diagnosed and a transverse colostomy performed emergently.His subsequent hospital course was unremarkable.Rectal anastomosis with diverting ileostomy is often performed in patients with low rectal cancers.In patients with anastomotic obstruction or severe stenosis,colonoscopy through diverting stoma should be avoided.Emergent operation to decompress the obstructed proximal colon is necessary in patients with a blind intestinal loop accompanied by HPVG.

Pitfalls in Positron Emission Tomography/Computed Tomography Imaging:Causes and Their Classifications

Objective To describe the pitfalls in positron emission tomography/computed tomography （PET/CT） imaging and classify them according to the principles of their generation. Methods We summarized retrospectively the ^18F-fluorodeoxyglucose （FDP） PET/CT imaging pitfalls through reviewing the PET/CT images of 872 patients. The pitfalls were divided into artifacts and infrequent physiological uptake, and the artifacts were further classified according to their causes. Meanwhile, we calculated the incidences of various pitfalls. Whether the PET/CT pitfalls influenced the diagnostic decision was analyzed. The appearances of pitfalls in PET were also described. Results Pitfalls could be found in PET/CT images of 684（78.4%） patients. Artifacts were found in 664 （76.15%） patients, and could be classified into self-factor artifacts and equipment-or technology-related artifacts. Among self-factor artifacts, respiratory motion （57.5%）, postprandial or hyperglycemia artifacts （2.41%）, and metal or high density matter artifacts （1.38%） were frequent. As for equipment-or tectmology-related factors, injection point outleakage or radiotracer contamination （13.88%） and truncation artifacts （1.83%） were most common ones. Infrequent physiological FDG uptakes, including fatty up-take, endometrial uptake, and bilateral breast feeding period uptake, were found in 20 （2.29%） patients. Among all pitfalls, the artifacts in 92 （13.4%） patients and infrequent physiological uptakes in 6 （0.88%） patients affected the diagnostic results. Artifact images in PET could be described as hot or cold area and the images of infrequent physiological uptake were always shown as hot area. Conclusions The incidence of pitfall in PET/CT imaging was high and the causes of pitfalls are various. Among all causes that artifacts generated, respiratory motion is the most common. Some pitfalls may disturb clinical physicians＇ decision, so it is important to recognize artifacts and physiological uptake, and distinguish them from pathological uptakes.

Increased risk of second malignancy in pancreatic intraductal papillary mucinous tumors: Review of the literature

AIM: To analyze the available evidence about the risk of extrapancreatic malignancies and pancreatic ductal adenocarcinoma associated to pancreatic intraductal papillary mucinous tumors(IPMNs).METHODS: A systematic search of literature was undertaken using MEDLINE, EMBASE, Cochrane and Web-of-Science libraries. No limitations for year of publication were considered; preference was given to English papers. All references in selected articles were further screened for additional publications. Both clinical series and Literature reviews were selected. For all eligible studies, a standard data extraction form was filled in and the following data were extracted: study design, number of patients, prevalence of pancreatic cancer and extrapancreatic malignancies in IPMN patients and control groups, if available.RESULTS: A total of 805 abstracts were selected and read; 25 articles were considered pertinent and 17 were chosen for the present systematic review. Eleven monocentric series, 1 multicentric series, 1 casecontrol study, 1 population-based study and 3 case report were included. A total of 2881 patients were globally analyzed as study group, and the incidence of pancreatic cancer and/or extrapancreatic malignancies ranged from 5% to 52%, with a mean of 28.71%.When a control group was analyzed(6 papers), the same incidence was as low as 9.4%.CONCLUSION: The available Literature is unanimous in claiming IPMNs to be strongly associated with pancreatic and extrapancreatic malignancies. The consequences in IPMNs management are herein discussed.

What is a reliable CT scan for diagnosing splenosis under emergency conditions?

Splenosis is a condition in which splenic tissue is present in a non-anatomical position. Implants of splenic tissue can mimic neoplasms and only specific examinations can confirm the correct diagnosis. Here we report a case of a 23-year-old male patient with a history of surgical splenectomy during childhood after trauma. He was admitted to the emergency department with acute bowel obstruction. An abdominalpelvic computed tomography (CT) scan revealed small bowel obstruction and the presence of two rounded, solid masses located in the rectal-vescical pouch. Quantitative analyses of the different density values in the arterial phase and early portal venous phase demonstrated that these lesions were highly vascularised (92 and 97 Hounsfield Units, respectively). The hypothesis of an ectopic splenic mass was made after evaluation of the CT images and clinical history. The acute bowel obstruction caused by adhesive intestinal syndrome was resolved by surgical adhesiolysis. The smallest mass adherent to the rectum was removed. Histopathologic examination confirmed the benign nature of the lesion, which consisted of splenic tissue.

Diagnosis of gastric duplication cyst by positron emission tomography/computed tomography: A case report

BACKGROUND Gastric duplication cysts(GDCs)are extremely uncommon lesions and the definitive diagnosis of GDCs is challenging for gastrointestinal specialists.It is important that a differential diagnosis is performed to rule out the possibility of other diseases,mainly malignancies with a cystic component.Despite the use of multiple diagnostic modalities including endoscopy,the preoperative diagnosis of GDCs is challenging.CASE SUMMARY A 53-year-old female patient with a GDC was confirmed by positron emission tomography/computed tomography(PET/CT)instead of more conventional procedures such as endoscopic ultrasonography-guided fine needle aspiration(EUS-FNA).We propose that 18F-FDG-PET/CT has higher accuracy than EUSFNA and may be an effective technique for the characterization of duplication cysts.CONCLUSION Preoperative diagnosis of GDCs in adults is difficult largely due to their rarity and the absence of characteristic findings.In addition,few endoscopists include GDCs in the differential diagnosis when they encounter a lesion with cystic characteristics.18F-FDG-PET/CT with additional imaging data,may complement EUS-FNA in the diagnosis of GDCs.

螺旋CT诊断支气管扩张

目的 :评价螺旋CT高分辨率扫描对支气管扩张诊断的可靠性 方法 :回顾和分析我院本年度经CT扫描确诊的支气管扩张的 2 0例病例 ,均采用螺旋CT高分辨率扫描 ,骨算法重建图像 结果 :支气管扩张的三种类型均得以很好显示 结论

Difference of dilation resistance to coronary stenting between fibrous plaques and lipid-rich plaques

Background Dilation resistance to stenting in non-calcified coronary plaques was compared in patients with percutaneous coronary intervention （PCI） in order to confirm the clinical usefulness of multislice computed tomography in examining coronary plaque type and to provide information pertaining to the effects of plaque type on dilatation resistance.