Hepatocellular cancer response to radiofrequency tumor ablation: contrast-enhanced ultrasound

Radiofrequency ablation (RFA) is increasingly being used as percutaneous treatment of choice for patients with early stage hepatocellular carcinoma (HCC). An accurate assessment of the RFA therapeutic response is of crucial importance, considering that a complete tumor ablation significantly increases patient survival, whereas residual unablated tumor calls for additional treatment. Imaging modalities play a pivotal role in accomplishing this task, but ultrasound (US) is not considered a reliable modality for the evaluation of the real extent of necrosis, even when color/power Doppler techniques are used. Recently, newer microbubble-based US contrast agents used in combination with grey-scale US techniques, which are very sensitive to non-linear behavior of microbubbles, have been introduced. These features have opened new prospects in liver ultrasound and may have a great impact on daily practice, including cost-effective assessment of therapeutic response of percutaneous ablative therapies. Technical evolution of CEUS focusing on findings after RFA are illustrated. These latter are detailed, cross-referenced with the literature and discussed on the basis of our personal experience. Timing of CEUS posttreatment assessment among with advantages and limitations of CEUS are also described with a perspective on further technologic refinement.

Inferomedial displacement of the meniscal free fragment: MR findings

PURPOSE

To define the accuracy of Magnetic Resonance (MR) in the diagnosis of inferomedial displacement of the meniscal fragment.

MATERIALS AND METHODS

The MR examinations of the knee performed between December 2002 and April 2004 on 676 patients (mean age 32 years) with knee trauma and subsequently subjected to arthroscopy were retrospectively reviewed to assess the presence of bucket-handle meniscal tear and inferomedial displacement of the meniscal free fragment. The MR examinations were performed using a superconductive 0.5 T MR unit with a transmitting/receiving coil dedicated for the extremities. The MR images were acquired with SE T1 and GE T2* sequences in the sagittal, coronal and axial planes with 3 mm thickness and 1 mm gap. The images were independently reviewed by two authors blinded to the arthroscopic findings. In case of disagreement, a third author, unaware of the arthroscopic findings, gave his judgment.

RESULTS

On MR images a bucket-handle meniscal tear was identified in 54/676 patients. In 6 out of 54 patients, an inferomedial meniscal fragment displacement of the medial meniscus with associated inflammatory synovial reaction around the fragment was detected. In one case an associated inflammatory bursal reaction with effusion around the distal insertion of the medial homolateral collateral ligament was detected. All cases were confirmed by arthroscopy and no statistical differences between the two authors were observed.

CONCLUSIONS

MR allows the detection of the inferomedial meniscal fragment displacement and a more correct planning of arthroscopy with a strong reduction of repeat interventions.

Virtual bronchoscopy in patients with central endobronchial stenosing lesions. Technique optimisation with single slice spiral CT

PURPOSE

To describe an original protocol for single slice spiral Computed Tomography (CT) virtual bronchoscopy in the evaluation of patients with central airway stenoses and compare the results with fibreoptic bronchoscopy.

MATERIALS AND METHODS

Ten patients (4 female and 6 male; age range 22-60 years; mean age 44 years) with endobronchial disease diagnosed by fibreoptic bronchoscopy (8 malignant tumours, 1 benign tumour and 1 fibroid stenosis) underwent virtual bronchoscopy with single slice spiral CT. A panoramic spiral CT scan of the whole chest was first obtained. Once the area of interest had been identified, a new contrast enhanced scan was performed, from bottom to top, with the following parameters: 2 mm slice thickness, 1 mm reconstruction index, 1.3 pitch, 120 Kvp, 80 mAs. Virtual bronchoscopy was generated with an upper threshold of -500 HU from the cross-sectional images of the second scan on a dedicated workstation. Axial, multiplanar reformations (MPR), and virtual endoscopy simulation were simultaneously visualised. Virtual CT bronchoscopy findings were compared with those of fibreoptic bronchoscopy.

RESULTS

The protocol we used to perform single slice spiral CT virtual bronchoscopy enabled us to obtain virtual bronchoscopy images that correlated well with fibreoptic bronchoscopy findings in all cases, as well as allowing the visualization of the airways beyond the stenoses. Information about tissues surrounding the tracheobronchial tree was also available from axial and MPR images. Only in 1 case were motion artefacts observed.

CONCLUSIONS

The set of the most appropriate parameters for performing virtual bronchoscopy by single slice spiral CT has not yet been standardized. In our opinion the appropriate selection of the protocol to adequately realize virtual bronchoscopic images is crucial when using CT devices such as the above, so as to achieve the correct balance between the quality of image definition and exposure dose.

Acute traumatic acromioclavicular joint lesions: role of ultrasound versus conventional radiography

PURPOSE

To assess the diagnostic potential of ultrasound as compared to conventional radiography in quantifying the anatomic and structural damage and determining the grade of acute traumatic lesions of the acromioclavicular (AC) joint.

MATERIALS AND METHODS

From September 2001 to September 2002, 18 patients (16 men, 2 women; age range: 17-78 years) who came to our Emergency Service with clinically suspected acute traumatic AC joint lesion were examined by ultrasonography with a variable frequency linear-array transducer (7.5-12 Mhz). The morphology of the AC joint peri-articular ligaments and soft tissues, distance between the edge of the acromion and the lateral margin of the clavicle, distance between the superior edge of the coracoid and the inferior margin of the clavicle were evaluated. Conventional radiography was performed prior to ultrasound using routine antero-posterior (A-P), single-film stress and "outlet" projections. All patients subsequently underwent clinical follow-up for a mean period of six months.

RESULTS

On US examination, all patients presented AC ligament lesion associated with consistent intra- and extra-articular sero-haemorrhagic effusion. Six of the 18 patients had suffered indirect trauma. Diastasis of the AC joint with ligament lesion not associated with involvement of coracoclavicular (CC) joint and with ligament integrity was observed. Twelve of the 18 patients had direct trauma. Changes to AC and CC ligaments with consequent diastasis of both joints were observed. Measurements of AC and CC distance obtained on US examination corresponded to those obtained at conventional radiography in the A-P projection. At clinical follow-up, no variation in the previously established diagnosis was recorded in any patient.

CONCLUSIONS

If appropriate methodology and adequate transducers are used, ultrasound is an accurate and reliable technique for the evaluation of acute AC joint injuries, complementing and correlating well with conventional radiography.

[Bleeding renal angiomyolipomas. CT findings]

PURPOSE

To describe our experience in three cases of abdominal haemorrhage caused by bleeding renal angiomyolipomas, which were studied with Computed Tomography (CT).

MATERIALS AND METHODS

A retrospective study carried out at our archives identified 3 patients (aged 58.6 on average) with renal angiomyolipomas clinically manifested with acute abdomen and haemorrhage. The patients underwent an emergency CT scan of the abdomen. One patient also under-went a subsequent renal angiography. All patients had surgery and histological characterizations of the renal lesions.

RESULTS

The CT study on all three patients allowed detection of a lesion in the kidneys with inhomogeneous density due to haemorrhage. Areas with fat-density values (-60 -80 UH) were always observable within the lesions. The lesions, measuring 5-9 cm, were located in the right kidney in two patients and in the left kidney in one.

CONCLUSIONS

In 40% of patients, renal angiomyolipoma may account for a picture of hypovolemic shock, so a correct diagnostic approach is important to guide the surgical approach. CT allows detection of the angiomyolipoma as the cause of the haemorrhage in most cases. The diagnosis is relatively simple when the lesion has typical features such as adipose content, whereas it may be difficult with non-typical aspects. Furthermore the fat content may also be detected in varying quantities in other renal lesions responsible for bleeding.

Nocardial adrenal abscess: CT and MR findings

To our knowledge, four bacterial adrenal abscesses in adults have already been reported in the international literature, but an adrenal Nocardia abscess has never been described previously. In this report the CT and MR imaging appearances and the differential diagnosis of the entity are discussed. The mass could resemble a malignancy. The observation of a rapid growth and colliquation of the mass helped in distinguishing it from a malignancy. The associated pulmonary infection provided a further clue to the diagnosis. The diagnosis was confirmed by surgery.

Arrhythmogenic right ventricular dysplasia: MR features

Arrhythmogenic right ventricular dysplasia (ARVD) is a heart disease characterized by a total or partial fat replacement of the myocardium. A total of 30 patients were studied with a suspected diagnosis of ARVD. Clinical criteria used for evaluation of ARVD were: (a) ventricular origin arrhythmias with a left bundle branch block configuration, (b) T-wave inversion in the anterior precordial leads, (c) ventricular kinetic alterations observed using echocardiography and angiography and (d) cardiac failure when there are no pathologies attributable to other heart diseases. All patients had serial EKG and echocardiography tests. One third of patients underwent angiocardiography; 7 of 30 had Holter; 7 of 30 had exercise test just to evaluate the effectiveness of the anti-arrhythmic therapy. All patients underwent MRI examination. The following MRI criteria were used: (a) high-intensity areas indicating the fatty substitution of the myocardium, (b) ectasia of the right ventricular outflow tract, (c) dyskinetic bulges, (d) dilation of the right ventricle and (e) enlargement of the right atrium. The diagnosis of ARVD was classified as highly probable for patients manifesting at least three positive criteria, probable with two positive criteria, dubious with one and negative in the absence of all criteria. Highly probable diagnosis of ARVD was made in 8 patients, probable in 4, dubious in 7 and negative in 11. The MRI technique is very effective in the assessment of ARVD. The MRI criteria may be helpful in the diagnosis of this condition.