Dynamic contrast-enhanced MR imaging in osteoid osteoma: relationships with clinical and CT characteristics.

OBJECTIVE: To correlate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) features to clinical and computed tomography (CT) morphological features of osteoid osteoma (OO). MATERIALS AND METHODS: Our institutional review board approved this retrospective study, waiving the need for informed consent. We included the 102 patients treated with interstitial laser ablation for histologically documented OO at our institution in 2008-2013. DCE-MRI variables were the time-enhancement pattern and rising slope (Sloperise) and CT variables were the bone and segment involved (OObone and OOsegment, respectively), OO location relative to the native cortex (OOcortex), nidus surface area, vessel sign, and largest neighboring-vessel diameter (Dmaxvessel). Descriptive statistics and correlations linking DCE-MRI findings to clinical and CT characteristics were computed. RESULTS: DCE-MRI showed early arterial peak enhancement in 95 (93%) cases, with a mean Sloperise of 9.30 ± 8.10. CT visualized a vessel sign in 84 (82%) cases with a mean Dmaxvessel of 1.10 ± 0.60 mm. By univariate analysis, Sloperise correlated significantly with pain duration and Dmaxvessel (r = 0.30, P = 0.003; and r = 0.22, P = 0.03; respectively). Analysis of variance showed that Sloperise correlated significantly with OObone (P < 0.001), with a steeper slope for OOs located in short or flat bones. CONCLUSION: This study suggests more abundant vascularization of OOs with long-lasting pain and location on short or flat bones.

Central element in liver masses, helpful, or pitfall?

A central element was first described in focal nodular hyperplasia (FNH) as a so-called "central scar," and is normally associated with this entity. However, many other liver masses may present with a central element. Depending on its appearance, and the lesion itself, central elements can be essential, helpful, or confusing for diagnosis. Indeed, nodules that develop on liver vascular disorders, fibrolamellar hepatocellular carcinoma, large hemangioma, peripheral cholangiocarcinoma, or epithelioid hemangioenthelioma often present with a central element, thus increasing the level of diagnostic confidence when present. On the other hand, central elements are rare or atypical in liver metastases, hepatocellular adenoma, or hepatocellular carcinoma. In this setting, the presence of a central element can lead to a misdiagnosis. The description and details of the imaging features of these different central elements, especially on MRI, as well as a thorough evaluation of the entire lesion, can improve the diagnostic performance in these cases.

Accuracy of water-enema multidetector computed tomography (WE-MDCT) in colon cancer staging: a prospective study.

PURPOSE: To assess the accuracy of water-enema multidetector computed tomography (WE-MDCT) in extra-rectal colon cancer staging. MATERIALS AND METHODS: Fifty-three patients (mean age 70 years) with extra-rectal colon cancer proven by colonoscopy and biopsy were prospectively evaluated by preoperative WE-MDCT. CT scans were both intraluminal (water enema or WE) and intravenous (iodinated) contrast enhanced (CE). All patients underwent surgery. Tumors were classified with the TNM staging system. Noted CT features were: tumor size and location; tumor form and edges; spread to the pericolic fat or neighboring organs; thickening of retroperitoneal fascia; number, size, and enhancement of the peritumoral lymph nodes. Tumors were classified on CT into 3 T-stage groups: T1/T2, T3, and T4. Lymph nodes were classified by their density after injection [positive over 100 Hounsfield units (HU)]. RESULTS: Tumor localization to the specific colon segment was correct in all the cases. The agreement between WE-MDCT staging and histopathology staging was good (k = 0.64). An irregular and bowl-shaped aspect of the external edges of tumor provided excellent sensitivity for T3/T4 inclusion (Se 97.7%, NPV 85.7%). Thickening of a fascia or the abdominal wall provided good specificity for T4 stage (Sp 88.1%, NPV 94.9%). Enhancement over 100 HU of at least one peritumoral lymph node was the best criterion of N+ staging (Sp 67.7%, NPV 87.5%). CONCLUSION: WE-MDCT permits good staging of colon cancer based on objective features.

[Dose reduction during CT coronary angiography]. / La réduction de dose en coroscanographie.

Dose delivery during CT coronary angiography with retrospective ECG gating is high especially due to the important slice overlapping. Optimization of the acquisition parameters is necessary to reduce patient exposure. First, the height of the scan field should be limited to the heart. Both kV and mA should be adjusted based on patient morphology. ECG gated exposure modulation with mA reduction during systole, a technique most applicable for patients with slow and regular heart rate, can result in a dose reduction up to 50%. The use of prospective ECG gating can also reduce patient dose. This technique also requires patients with slow and regular heart rate.

Non-traumatic calcifications/ossifications of the bone surface and soft tissues of the wrist, hand and fingers: a diagnostic approach.

In the absence of obvious trauma, the calcifications/ossifications of the bone surface and soft tissues of the wrist, hand and fingers can be challenging and may not be noticed or lead to unnecessary examinations and monitoring. Although these are usually benign conditions and despite a favorable spontaneous outcome, surgical resection may be required and recurrence may occur. In practice, only paraneoplastic syndromes such as secondary hypertrophic osteoarthropathy (Pierre Marie-Bamberger syndrome) may reveal a malignant tumor, most often pulmonary. We suggest a diagnostic approach based on the initial clinical presentation (acute pain, chronic pain, growth±pain) and the radiological features.

Appendicitis and diverticulitis of the colon: misleading forms.

Appendicitis and diverticulitis of the colon are the two main causes of febrile acute abdomen in adults. Diagnosis from imaging (ultrasound and CT) is usually easy. However, an imaging procedure which is not suitable for the clinical situation and an examination performed with the wrong protocol are sources of error and must be avoided. Anatomical variants, inflammatory cancers, complicated forms (perforation, secondary occlusion of the small intestine, peripheral abscesses, fistulae, pylephlebitis, liver abscesses) and associated signs related to a peritoneal inflammatory reaction (reflex ileus, reactive ileitis or salpingitis) can also lead to a wrong diagnosis.

Applications of phase-contrast velocimetry sequences in cardiovascular imaging.

AIMS: To describe and illustrate the main applications of phase-contrast flow quantification in cardiovascular imaging. CONCLUSION: Phase-contrast velocimetry sequences provide an accurate, reliable, reproducible and non-invasive study of blood flow, information which is sometimes not available from other investigation methods. The haemodynamic information obtained from these complement MRI angiography images. They appear to have a range of clinical applications, firstly improving pathophysiological understanding but also contributing to the treatment and follow-up strategy after surgical or endovascular treatment.