MDCT of benign liver tumors and metastases

Spontaneous internal hemorrhage of a giant hepatic hemangioma with infection: a case report and literature review

Spontaneous internal hemorrhage from a hepatic hemangioma is rare. This case describes a 59-year-old woman who was hospitalized with recurrent cough and fever for 6 months. The doctor thought that she had pneumonia, but other infectious diseases could not be ruled out. Therefore, related tests were performed and strong antibiotics were used, but the symptom of fever was persistent and recurred. Enhanced computed tomography (CT) findings showed a right hepatic giant hemangioma with hemorrhage, while tuberculosis, liver abscess, and immune disease were excluded by the physician. Because the patient’s fever was associated with a large hepatic hemangioma, the patient was transferred to surgery. During treatment, the amount of bleeding increased, so she underwent a right hepatic hemangioma resection in the emergency department. Her postoperative fever symptoms subsequently resolved. Pathological examination confirmed hemorrhagic necrosis with infection in hepatic hemangioma. Follow-up showed that the patient was afebrile.

Optimising the scan delay for arterial phase imaging of the liver using the bolus tracking technique

Objective:

To optimize the delay time before the initiation of arterial phase scan in the detection of focal liver lesions in contrast enhanced 5 phase liver CT using the bolus tracking technique.

Patients and Methods:

Delay - the interval between threshold enhancement of 100 hounsfield unit (HU) in the abdominal aorta and commencement of the first arterial phase scan. Using a 16 slice CT scanner, a plain CT of the liver was done followed by an intravenous bolus of 120 ml nonionic iodinated contrast media (370 mg I/ml) at the rate of 4 mL/s. The second phase scan started immediately after the first phase scan. The portal venous and delay phases were obtained at a fixed delay of 60 s and 90 s from the beginning of contrast injection. Contrast enhancement index (CEI) and subjective visual conspicuity scores for each lesion were compared among the three groups.

Results:

84 lesions (11 hepatocellular carcinomas, 17 hemangiomas, 39 other hypervascular lesions and 45 cysts) were evaluated. CEI for hepatocellular carcinomas appears to be higher during the first arterial phase in the 6 seconds delay group. No significant difference in CEI and mean conspicuity scores among the three groups for hemangioma, other hypervascular lesions and cysts.

Conclusion:

The conspicuity of hepatocellular carcinomas appeared better during the early arterial phase using a bolus tracking technique with a scan delay of 6 seconds from the 100 HU threshold in the abdominal aorta.

Management of an incidental liver mass

The increased use of sensitive imaging modalities has led to increased identification of the incidental liver mass (ILM). A combination of careful consideration of patient factors and imaging characteristics of the ILM enables clinicians to recommend a safe and efficient course of action. Using an algorithmic approach, this article includes pertinent clinical factors and the specific radiologic criteria of ILMs and discusses the indications for potential procedures. It is the aim of this article to assist with the development of an individualized strategy for each patient with an ILM.

Detection and characterization of benign focal liver lesions with multislice CT

MDCT is a rapidly evolving technique that significantly improves CT imaging for several indications including depiction of focal benign lesions. Imaging mainly profits from improved longitudinal spatial resolution allowing high-quality non-axial reformations and 3D reconstructions and CT angiography as well as rapid accurate multiphase imaging with short breath-holding periods. This review provides an overview of the current status of MDCT with respect to liver imaging and the implications for characterizing benign focal liver lesions. MDCT currently allows the acquisition of thin slices in daily routine diagnostics providing an improved detection rate of small liver lesions. Whereas large benign focal liver lesions exhibit typical patterns of morphology, attenuation and perfusion, which also may be assessed with single-slice scanners, small lesions remain challenging even with MDCT, since the specific criteria for confident diagnosis become more ambiguous. Here, MR imaging provides more detailed information about tissue components and the availability of liver-specific contrast agents, adding further impact to this technique. With respect to dose considerations, the number of necessary multiphase scans as well as the application of very thin collimation should be strictly checked for each patient undergoing MDCT based on the individual clinical situation and question.

Detection of liver metastases under 2 cm: comparison of different acquisition protocols in four row multidetector-CT (MDCT)

This study compared different acquisition protocols performance to detect small liver metastases (<2 cm). Thirty consecutive patients with histologically proven hepatic metastases were explored by MDCT at the liver equilibrium phase by four successive acquisitions. We compared the following protocols (1-4): 5/30/1.5 (section thickness/table speed/pitch); 5/15/0.75; 5/11.25/0.75; and 2.5/15/1.5 with the same X-ray dose. The gold standard was based on patient radiological follow-up. Evolutive lesions were considered as true positive (TP). The described lesions, not found on the follow-up exams despite tumoral progression, were considered as false positive (FP). Stable lesions could not be considered as metastasis and were eliminated. One hundred and seventy-six lesions were detected: 61 TP and 91 FP. Twenty-four lesions were eliminated. The mean kappa values for protocols 1, 2, 3 and 4 were, respectively, 0.43, 0.68, 0.73 and 0.51 (0.61-0.80: substantial agreement) and the mean areas under the ROC curve were, respectively, 0.76, 0.87, 0.86 and 0.80. The results of protocols 2 and 3 were significantly superior to those of protocols 1 and 4. MDCT protocols using thin sections or an increased table speed are less efficient in detecting small metastases.

The diagnosis and management of benign hepatic tumors

Benign hepatic tumors include a broad spectrum of regenerative and true neoplastic processes. Because of advances in imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI) as well as progress in immunohistochemistry, accurate diagnosis can now be made in a large percentage of patients without surgical laparotomy or resection. This article will focus on the pathogenesis, diagnosis, and management of focal benign lesions of the liver. Many of these tumors present with typical features in various imaging studies. On occasions, biopsies are required and/or surgical removal is needed. The most common benign hepatic tumors include cavernous hemangioma, focal nodular hyperplasia, hepatic adenoma, and nodular regenerative hyperplasia. In the majority of cases of benign hepatic tumors, patients are asymptomatic, and no treatment is indicated. The main indication for treatment is the presence of significant clinical symptoms or suspicion of malignancy or fear of malignant transformation.

Abdominal Imaging with Multidetector Computed Tomography

This article is based on lectures which were given at the Multidetector Computed Tomography Conference in Washington, D.C. on September 13-14, 2003. Specifically, this article summarizes the Abdominal Imaging Section of this meeting. It is not an exhaustive review, but it rather attempts to highlight key points related to preoperative MDCT of the liver, MDCT of pancreas, MDCT urography and MDCT of thoracoabdominal and spinal trauma.

[Ultrasound imaging of focal liver lesions with contrast agents: which clinical applications?]

The contrast-enhanced ultrasonography is a promising technique for the diagnosis of focal liver lesion with an increased sensitivity for the tumour detection and a direct visualization of the tumour vascularity. The future applications of this technique will probably depend on the clinical context: in case of suspicion of benign tumour, contrast injection should be able to facilitate the characterization of hemangiomas and focal nodular hyperplasia, when hepatic metastases are researched, it may improve the detection of small lesions in cirrhotic patients, it may facilitate the detection of small hepatocellular carcinomas and find a place in the systematic screening for these tumours. The recently published data are encouraging, but a confirmation of the clinical interest of this technique, and its place within the imaging diagnostic strategies still have to be performed.