High-intensity focused ultrasound (HIFU): effective and safe therapy for hepatocellular carcinoma adjacent to major hepatic veins

Hepatocellular carcinoma (HCC) is an especially frequent malignancy in China. Radiofrequency ablation, percutaneous ethanol injection, transarterial chemoembolization, cryoablation, microwave coagulation, and laser-induced interstitial thermotherapy all offer potential local tumor control and occasionally achieve long-term disease-free survival. High-intensity focused ultrasound (HIFU), as a noninvasive therapy, can be applied to treat tumors that are difficult to treat with other techniques. The preliminary results of HIFU in clinical studies are encouraging. The aims of this investigation were to assess the efficacy of the system in obtaining necrosis of the target tissue and to determine whether HIFU ablation is hazardous to adjacent major blood vessels. Over 7 years, thirty-nine patients with HCC were enrolled in this investigation. The inferior vena cava (IVC), main hepatic vein branches, and the portal vein and its main branches were evaluated. The distance between tumor and main blood vessel was less than 1 cm in all these enrolled patients. Contrast-enhanced MRI was used to evaluate the perfusion of tumors and major blood vessels. We conducted HIFU ablation for the treatment of 39 patients with 42 tumors, with each tumor measuring 7.4 ± 4.3 (1.5–22) cm in its greatest dimension. Among the 39 patients, 23 were males and 16 females. The average age was 53.2 years (range 25–77 years). Thirty-seven patients had a solitary lesion, one had two lesions, and the remaining one had three lesions. Nineteen lesions were located in the right lobe of liver, 18 in the left lobe, and 5 in both right and left lobes. Among the 42 tumors, 25 were adjacent to 1 blood vessel, 12 adjacent to 2 main vessels, 2 adjacent to 3 main vessels, and 1 adjacent to 4 main vessels. Twenty-one of the 42 tumors were completely ablated, while the rest of the tumors were ablated by more than 50% of lesion volume after one session of HIFU. No major blood vessel injury was observed in any subject after 23.8 ± 17.2 months follow-up. HIFU can achieve complete tumor necrosis even when the lesion is located adjacent to the major hepatic blood vessels. Short-term and long-term follow-up results show that HIFU can be safely used to ablate the tumors adjacent to major vessels. Lian Zhang and Hui Zhu contributed equally to this research, which was supported by the National Natural Science Foundation of China (grant no. 30171060).     

Low-fat angiomyolipoma of the liver studied with contrast-enhanced ultrasound and multidetector computed tomography

We report the case of a 30-year-old woman with persistent pain at the right hypochondrium, relapsing fever, and normal serum tests. Ultrasound showed a hyperechoic inhomogeneous mass; following sulfur hexafluoride injection, uniform enhancement at 14-16 s and rapid wash-out at 26 s was found. Multidetector computed tomography showed an inhomogeneously hypodense mass, with no detectable negative density values, characterized by inhomogeneous enhancement at the arterial phase and wash-out at the portal phase. Histopathology demonstrated a hepithelioid angiomyolipoma with a poor fatty component. This diagnosis should always be considered in the presence of a very rapid wash-out after intravenous contrast injection. However, a hepatocellular carcinoma cannot be excluded and the final diagnosis of low-fat angiomyolipoma must be pathologically proved based on immunohistochemistry.     

Effects of oxytocin on high intensity focused ultrasound (HIFU) ablation of adenomysis: A prospective study

Objective

To investigate the effects of oxytocin on high-intensity focused ultrasound (HIFU) ablation for the treatment of adenomyosis.

Materials and methods

Eighty-six patients with adenomyosis from three hospitals were randomly assigned to the oxytocin group or control group for HIFU treatment. During HIFU treatment, 80 units of oxytocin was added in 500 ml of 0.9% normal saline running at the rate of 2 ml/min (0.32 U/min) in the oxytocin group, while 0.9% normal saline was used in the control group. Both patients and HIFU operators were blinded to oxytocin or saline application. Treatment results, adverse effects were compared.

Results

When using oxytocin, the non-perfused volume (NPV) ratio was 80.7 ± 11.6%, the energy-efficiency factor (EEF) was 8.1 ± 9.9 J/mm³, and the sonication time required to ablate 1 cm³ was 30.0 ± 36.0 s/cm³. When not using oxytocin, the non-perfused volume ratio was 70.8 ± 16.7%, the EEF was 15.8 ± 19.6 J/mm³, and the sonication time required to ablate 1 cm³ was 58.2 ± 72.7 S/cm³. Significant difference in the NPV ratio, EEF, and the sonication time required to ablate 1 cm³ between the two groups was observed. No oxytocin related adverse effects occurred.

Conclusion

Oxytocin could significantly decrease the energy for ablating adenomyosis with HIFU, safely enhance the treatment efficiency.     

Evaluation of the therapeutic efficacy of high-intensity focused ultrasound ablation of hepatocellular carcinoma by three-dimensional sonography with a perflubutane-based contrast agent

Objective

We performed contrast-enhanced three-dimensional sonography (CE 3D US) with a perflubutane-based contrast agent to immediately evaluate the completeness of ablation of small hepatocellular carcinoma (HCC) lesions by extracorporeal high-intensity focused ultrasound (HIFU).

Subjects and methods

Twenty-one HCC lesions were treated by a single ultrasound-guided HIFU ablation session, and CE 3D US was performed before, immediately after, and 1 week, and 1 month after HIFU, and contrast-enhanced CT (CE CT) or contrast-enhanced MRI (CE MRI) was performed before HIFU, 1 week and 1 month after HIFU, and during the follow-up period.

Results

Immediately and 1 month after HIFU, 17 lesions were evaluated as adequately ablated by CE 3D US, and the other 4 lesions as residual tumors. One month after HIFU, 18 were evaluated as adequately ablated by CE CT or CE MRI, and the other 3 as residual tumors. The evaluation by CE 3D US immediately after HIFU and by CE CT or CE MRI 1 month after HIFU was concordant with 20 lesions. The kappa value for agreement between the findings of CE 3D US and other modalities by two blinded observers was 0.83. When the 1-month CE CT or CE MRI findings were used as the reference standard, the sensitivity, specificity, and accuracy of CE 3D US immediately after HIFU for the diagnosis of the adequate ablation were 100%, 75%, and 95%, respectively.

Conclusion

CE 3D US appears to be a useful method for immediate evaluation of therapeutic efficacy of HIFU ablation of HCC lesions.     

Preoperative staging of renal cell carcinoma using triphasic helical computed tomography

Objective

To determine if staging of renal cell carcinoma (RCC) can be predicted from preoperative triphasic helical computed tomography (CT) findings.

Patients and methods

We reviewed the triphasic helical CT scans of 48 consecutive patients with pathologic diagnosis RCCs. All tumors were staged according to the 2002 version of TNM staging system. The preoperative radiologic staging was compared with postoperative pathologic staging. Agreement between the two staging systems was determined using the kappa test.

Results

Comparison between triphasic helical CT staging and pathologic staging showed harmony in all lesions in stage T1a, and T1b. Triphasic helical CT over diagnosed two cases of stage T1b regarded as stage T3a while agreement was noted in all cases of stage T2. Harmony was noted between triphasic helical CT and pathologic staging in two lesions stage T3a, four lesions in stage T3b, and two lesions stage T4. The agreement between triphasic helical CT and pathologic T stages was perfect (K = 0.941). Forty-two cases were staged N0, one case was N1, and five cases were staged N2 by triphasic CT. Three cases were over staged, and six cases were under staged while, 39 were correctly N staged. The agreement between triphasic helical CT and pathologic N staging was poor (K = 0.33).

Conclusion

The agreement between the preoperative triphasic helical CT staging and postoperative pathologic T staging is perfect, while agreement in N stages is poor. So T staging of RCC can be predicted from triphasic helical CT findings while N staging cannot be predicted preoperatively.     

Multi-detector computed tomography angiography of the hepatic artery in liver transplant recipients

Purpose: To evaluate the ability of multi-detector row computed tomography angiography (CTA) in detecting hepatic artery complications in the follow-up of liver transplant patients, performing volume-rendering as reconstruction technique.

Material and Methods: The anatomy of hepatic artery was studied in 27 liver transplant recipients with a four-row CT scanner using the following parameters: collimation, 1 mm; slice width, 1 mm; table feed, 6-8 mm/s; spiral reconstruction time, 0.5 s; reconstruction interval, 0.5 mm; mAs, 160; kVp, 120. Before the study, the patients received 1000 ml of water as oral contrast agent to produce negative contrast in the stomach and the small bowel. A non-ionic contrast medium was infused intravenously at a rate of 5 ml/s with a bolus tracking system. Volume-rendering of hepatic artery was performed with the 3D Virtuoso software.

Results: The celiac trunk, the hepatic artery, and the right and left hepatic arteries were successfully displayed in high detail in all patients. Side branches, including small collaterals, and hepatic artery anastomosis could also be readily visualized. Volume-rendered CTA detected six hepatic artery stenoses, two hepatic artery thromboses, and two intrahepatic pseudoaneurysms. In two cases, CT detected hepatic artery stenosis with a diameter reduction of less than 50%, while digital subtraction angiography showed a normal artery.

Conclusion: Volume-rendered multi-detector CTA is a promising non-invasive technique, since it allows images of high quality to be generated with excellent anatomical visualization of the hepatic artery and its complications in liver transplant recipients.     

MRI对TAE联合HIFU治疗肝癌的评价

目的探讨TAE联合高强度超声聚焦刀(HIFU)治疗肝癌的疗效及MRI对其的评价。方法随机选择肝癌20例,其中原发肝癌12例,转移癌8例,行肝动脉栓塞化疗后行HIFU治疗,治疗前后MRI平扫及增强扫描了解疗效。结果TAE联合HIFU治疗2周后,16例MRI显示肿瘤区完全无强化,肿瘤血供阻断呈凝固性坏死;4例肿瘤区周边少许血供强化,追加HIFU治疗后肿瘤完全无强化,肿瘤血供完全阻断。1个月后复查肿瘤缩小1/3者10例,完全坏死液化4例,稳定无明显缩小6例,未见肿瘤增大或扩散转移。结论TAE联合HIFU治疗肝癌是一种微创、安全的,有望达到介入性根治目的的治疗方法。     

Operation of bolus tracking system for prediction of aortic peak enhancement at multidetector row computed tomography: pharmacokinetic analysis and clinical study

PURPOSE: The present study was performed to identify the theoretical background for optimal use of the bolus tracking system by analyzing the changes in the initial slope of the aortic time-enhancement curve (TEC). MATERIALS AND METHODS: We calculated the contrast medium aortic arrival time (TAR), the time to reach the trigger threshold (effective TAR), the slope of the linear equation of the enhancement unit (enhancement rate), and the time to peak aortic enhancement from the TECs of the pharmacokinetic analysis and retrospective clinical study. RESULTS: In the pharmacokinetic analysis, the enhancement rate-simulated under conditions of injection duration 30 s and iodine load per body weight 500 mg/kg-was 27.1 HU/s. In the clinical study, the enhancement rate was 27.9 +/- 3.0 HU/s. A correlation was found between the TAR and the enhancement rate, indicating that enhancement rates decrease with increasing TAR. It took 22.7 +/- 0.5 s to reach maximum enhancement of the aorta from the trigger threshold of an increase of 100 HU and injection duration at 30 s. CONCLUSION: We found that cardiac output differences are strongly dependent on the TAR and that most of the differences disappeared during the phase until effective TAR.     

Role of multidetector computed tomography (MDCT) in diagnosis of subhepatic appendicitis

Background

Acute appendicitis is a common surgical condition that is usually managed with early surgery, and is associated with low morbidity and mortality. However, some patients may have atypical symptoms and physical findings that may lead to a delay in diagnosis and increased complications.Ascending subhepatic appendicitis presenting with right upper abdominal pain may be clinically indistinguishable from acute pathology in the gallbladder, liver, biliary tree, right kidney and right urinary tract.

Aim of the work

To study the role of multidetector computed tomography in diagnosis of subhepatic appendicitis.

Subjects & methods

In the current study, we included fifteen patients diagnosed radiologically and confirmed surgically as subhepatic appendicitis.Ultrasonography followed by multidetector computed tomographic examination were performed to all patients before surgery.

Results

The clinical diagnosis of the patients included in this study at presentation was acute cholecystitis in four patients, pyelonephritis in three, and ureteric colic in three. Five patients were referred with uncertain diagnosis.The presence of subhepatic appendicitis was confirmed sonographically only in two patients. Computed tomography (CT) identified correctly subhepatic appendicitis in all cases.

Conclusion

Our study indicates the usefulness of multidetector CT in diagnosing atypical ascending subhepatic appendicitis.     

Diagnosis of spinal dural arteriovenous fistula with multidetector row computed tomography: a case report

Spinal dural arteriovenous fistulas are a rare cause of myelopathy. Nonspecific symptoms may delay the diagnosis. Magnetic resonance imaging and spinal angiography are routinely used to establish the diagnosis. In our case abnormalities on magnetic resonance imaging only suggested spinal dural arteriovenous fistulas. Multidetector row computed tomography (MRCT) led to the diagnosis which was confirmed by angiography.     

Effect of contrast-enhanced computed tomography on diagnosis and management of acute abdomen in adults

AIM: To determine the impact of computed tomography (CT) on the diagnosis and treatment plan in patients with acute abdominal pain. MATERIALS AND METHODS: A prospective study was undertaken in 125 adult patients presenting with acute abdominal pain (74 men and 51 women; 40.2 +/- 19.3 years; range, 18-92). Changes in diagnosis, gain in percentage diagnostic certainty and changes of treatment plan of the surgeons in the emergency department before and after CT were evaluated. Pre- and post-CT diagnoses were compared with the final diagnoses. RESULTS: CT findings changed the initial diagnosis in 40 (32.0%) patients. The diagnostic certainty was 58.3 +/- 22.9% before CT, and its gain after CT was 21.9 +/- 18.5 points (P < 0.0001). Post-CT diagnoses were consistent with the final diagnosis in 116 patients (92.8%), while pre-CT diagnoses were correct in 89 patients (71.2%; P < 0.0001). Initial treatment plans were changed in 31 (24.8%) patients after CT. In 57 (45.6%) patients, CT information changed diagnoses and/or treatment plans. No significant differences were observed in the diagnosis, diagnostic certainty and treatment plan among four surgeons. CONCLUSION: Contrast-enhanced CT frequently changed the clinical diagnoses with increased diagnostic certainty and the initial treatment plans.     

Improving mass measurement of coronary artery calcification using threshold correction and thin collimation in multi-detector row computed tomography: in vitro experiment

RATIONALE AND OBJECTIVES: This in vitro study was designed to improve the accuracy of coronary calcium mass measurement from computed tomography (CT) images by developing threshold-based calcium CT number correction and thin-slice spiral techniques. MATERIALS AND METHODS: A cardiac CT phantom containing simulated calcified cylinders of known calcium density was scanned with sequential 4 x 2.5-, spiral 16 x 1.5-, and spiral 16 x 0.75-mm collimation on 4- and 16-detector row CT scanners. The images obtained from the spiral scans were reconstructed in various slice widths. The calcified cylinders were imaged and their mean CT number and size were measured at thresholds ranging from 50 to 390 Hounsfield unit. The calcium mass measured was compared with the actual value to determine errors, and threshold-based correction factors were derived to minimize the errors. RESULTS: The minimum amount of measurable calcium in 1-mm cylinder was 0.3 mg at the 16 X 1.5-mm protocol and 0.2 mg at the 16 x 0.75-mm protocol. Compared with 2.5-mm sequential protocol, thin-slice spiral protocols yielded a higher radiation exposure and lower or similar image noise levels. The error in calcium mass after correction was significantly smaller than that in measured mass (P < .0001) and was consistent between the imaging protocols (P = .49). The accuracy of mass measurements was clearly improved by using thin-slice imaging protocols especially in 200-mg/cm3 calcium density (P < .0001). CONCLUSION: The accuracy of calcium mass CT measurement can be improved by threshold-based calcium CT number correction and thin collimation spiral techniques.     

镇静止痛条件下聚焦超声治疗实体肿瘤的初步临床研究

目的初步评价镇静止痛条件下采用高强度聚焦超声(HIFU)对良性和晚期恶性肿瘤患者实施消融和姑息性消融治疗的安全性和有效性。方法静脉应用芬太尼(1μg/kg)及咪唑安定(0.03mg/kg)创建镇静止痛条件,应用JC型HIFU治疗系统对23例良性和58例晚期恶性肿瘤患者实施消融和姑息性消融治疗,观察镇静止痛药物及HIFU消融治疗的近期疗效、不良反应。结果在镇静止痛条件下,81例患者共进行112例次HIFU消融手术,其中23例良性肿瘤患者治疗26例次,58例恶性肿瘤患者姑息性治疗86例次,共治疗153个病灶。在可评价的疗效中,病灶体积消融率达到50%以上的病灶占81%(89/110),其中恶性肿瘤为72.2%(52/72),良性肿瘤为97.4%(37/38)。恶性肿瘤患者中81.3%(13/16)的患者肿瘤标志物下降>50%;肿瘤相关症状缓解率77%(30/39)。镇静止痛药物不良反应包括恶心、呼吸频率过缓、幻视等,HIFU治疗的主要副反应包括,治疗区疼痛及肿胀等。未出现三度以上镇静止痛药物或HIFU治疗的相关并发症。结论在镇静止痛条件下,HIFU消融治疗实体肿瘤具有较好的安全性、有效性和可操作性。     

The prevalence of simple renal and hepatic cysts detected by spiral computed tomography

AIM: To provide a definitive evaluation of the prevalence of simple renal and hepatic cysts using spiral computed tomography (CT). PATIENTS AND METHODS: Contrast-enhanced abdominal CT studies from 617 patients (295 women, 322 men) attending for investigations unrelated to renal or hepatic pathology were included. The number of renal cysts, their location and the diameter of the largest cyst were recorded. Hepatic cysts were recorded as being either present or absent. RESULTS: Two hundred and fifty-four patients (41%) were found to have simple renal cysts and 110 patients were found to have simple hepatic cysts (18%). Both renal and hepatic cysts became more common with age. Renal cysts were significantly more common at all ages in men (p=0.001), and increased in both size (p=0.02) and number (p<0.05) with age. CONCLUSION: A major discrepancy has, until now, existed between autopsy prevalence of renal cysts and prevalence as reported by in-vivo third-generation CT or sonography studies. Using newer spiral CT machines, we have generated prevalence data closer to post-mortem findings. We have also shown a significant, but age dependent, association between the presence of simple hepatic and simple renal cysts (p=0.001)     

Hepatocellular carcinoma treated with radio frequency ablation: an early evaluation with magnetic resonance imaging

PURPOSE: To determine the usefulness of nonenhanced T1-weighted spoiled gradient-recalled acquisition in the steady-state (SPGR) MRI in the early assessment of the efficacy of radio frequency (RF) therapy for hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A total of 23 patients with 28 HCC nodules treated with percutaneous RF ablation underwent nonenhanced MRI within two days after the RF procedure and contrast-enhanced computed tomography (CT) one week after. MR assessment of ablation efficacy according to the concentric zonal pattern on T1-weighted SPGR imaging was compared with the one-week CT and presence of local recurrence by means of follow-up study for 12 months or more. RESULTS: In 18 of 28 ablated nodules, SPGR images revealed a central hyperintense zone covering the entire tumor, CT showed a nonenhanced area covering the entire tumor, and no local recurrence was demonstrated in the follow-up studies. In nine of 28 nodules, the central hyperintense zone did not cover the entire tumor; and local recurrence was demonstrated in three nodules. In the remaining one nodule, no signal change was seen in the treated area on SPGR images and CT showed the presence of residual viable tumor. CONCLUSION: Nonenhanced T1-weighted MRI was considered useful for early assessment of the efficacy of RF therapy for HCC.     

Central lower attenuating lesion in the ablation zone on immediate follow-up CT after percutaneous radiofrequency ablation for hepatocellular carcinoma: Incidence and clinical significance

Purpose

The purpose of this study was to evaluate the incidence of central lower attenuating (CLA) lesion in the ablation zone seen on immediate follow-up CT images after percutaneous radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC), and the correlation of CLA lesions and local tumor progression (LTP).

Subjects and methods

The study group included 146 patients with 167 ablation zones that had undergone follow-up CT examinations for more than 12 months after percutaneous RFA. CLA lesions corresponding to index tumors and ablative margins (safety margins) were evaluated in the ablation zones seen on immediate follow-up CT including coronal and sagittal multiplanar reformatted (MPR) images with narrow window width settings.

Results

CLA lesions were depicted on 48 of 167 ablation zones (28.7%) on immediate follow-up CT images. Among the 48 ablation zones with CLA lesions, 27 (56.3%, 27/48) had ablative margins on all three of the orthogonal MPR images and they showed no LTP (0%) on follow-up CT examinations. Three of the ablation zones with CLA lesions (6.3%, 3/48) having an ablative margin on one plane only also showed no LTP (0%). LTP was observed in 2 of 18 ablation zones (11.1%) that had CLA lesions without ablative margins on all three planes. In the remaining 119 ablation zones without CLA lesions, 5 (4.2%, 5/119) showed LTP.

Conclusion

CLA lesions in ablation zones were occasionally (28.7%) seen on immediate follow-up CT images after RFA for HCCs. The presence of CLA lesions with ablative margins might be a negative predictor of LTP.     

Assessment of cardiac volumes by multidetector computed tomography

Quantitative evaluation of cardiac ventricular and atrial chamber sizes, ventricular function, and left ventricular mass is important for prognosis and management. The most common methods for quantitative evaluation have been echocardiography and cardiac magnetic resonance imaging. Recently, multidetector cardiac computed tomography (CCT) technology has evolved to permit imaging of cardiac structure, function, volume, and mass. Potential advantages of CCT over existing methods include 3-dimensional volumetric assessment of cardiac chambers which are free of geometric assumptions and the ability to obtain true, on-axis imaging planes with double-oblique orientations.     

Whole tumour first-pass perfusion using a low-dose method with 64-section multidetector row computed tomography in oesophageal squamous cell carcinoma

Purpose

To propose a low-dose method at tube current-time product of 50 mAs for whole tumour first-pass perfusion of oesophageal squamous cell carcinoma using 64-section multidetector row computed tomography (MDCT), and to assess the original image quality and accuracy of perfusion parameters.

Materials and methods

Fifty-nine consecutive patients with confirmed oesophageal squamous cell carcinomas were enrolled into our study, and underwent whole tumour first-pass perfusion scan with 64-section MDCT at 50 mAs. Image data were statistically reviewed focusing on original image quality demonstrated by image-quality scores and signal-to-noise (S/N) ratios; and perfusion parameters including perfusion (PF, in ml/min/ml), peak enhanced density (PED, in HU), time to peak (TTP, in seconds) and blood volume (BV, in ml/100 g) for the tumour. To test the interobserver agreement of perfusion measurements, perfusion analyses were repeatedly performed.

Results

Original image-quality scores were 4.71 ± 0.49 whereas S/N ratios were 5.21 ± 2.05, and the scores were correlated with the S/N ratios (r = 0.465, p < 0.0001). Mean values for PF, PED, TTP and BV of the tumour were 33.27 ± 24.15 ml/min/ml, 24.06 ± 9.87 HU, 29.42 ± 8.61 s, and 12.45 ± 12.22 ml/100 g, respectively. Intraclass correlation coefficient between the replicated measurements of each perfusion parameter was greater than 0.99, and mean difference of the replicated measurements of each parameter was close to zero.

Conclusion

Whole tumour first-pass perfusion with 64-section MDCT at low-dose radiation could be reproducible to assess microcirculation in oesophageal squamous cell carcinoma without compromising subjective original image quality of the tumour.     

Low-high and high-low biphasic injection forms in computed tomography examinations of the upper abdomen

Purpose: To analyze the influence of different biphasic and monophasic injection rate protocols in abdominal computed tomography (CT).

Material and Methods: A randomized, consecutive, parallel group study was designed and conducted in 60 patients studied with the same CT helical protocol. Patients were randomly distributed into three groups: (A) monophasic (120 ml at 2.5 ml/s); (B) low-high biphasic (120 ml, first 60 ml at a rate of 2 ml/s, the other 60 ml at 2.5 ml/s); and (C) high-low biphasic (120 ml, first 60 ml at a rate of 2.5 ml/s, the other 60 ml at 2 ml/s). All patients were injected with 300 mg I/ml non-ionic contrast media at a fixed delay time of 55 s. Contrast enhancement efficacy was evaluated by attenuation coefficient measurements.

Results: Although non-significant, monophasic protocol enhancements were higher than biphasic protocol enhancements in all measurements except aortic bifurcation (p = 0.003). At this level, biphasic protocols obtained an increased mean enhancement from 7.6% to 2.5% compared to monophasic protocols.

Conclusion: Monophasic contrast agent injection in helical CT of the upper abdomen produces a higher enhancement of parenchymal and venous structures. No significant difference was observed between low-high and high-low biphasic protocols.     

Multidetector row computed tomography in bowel obstruction. Part 1. Small bowel obstruction

Multidetector row computed tomography (MDCT) has the potential to provide high-resolution multiplanar imaging that can help in accurate diagnosis of small bowel obstruction. Reformatted multiplanar images can increase diagnostic confidence in identifying transition points causing obstruction and also allow accurate delineation of various pathological conditions. Accurate and early diagnosis of complications associated with small bowel obstruction can also help in the clinical management of patients. In appropriate clinical scenarios MDCT angiograms may also be performed. Furthermore the rapid acquisition of images within one breath-hold reduces misregistration artefacts than can occur in critically ill or uncooperative patients. The following is a review of common and unusual diseases causing small bowel obstruction as revealed on MDCT.