Sabina Giusti

Ultrasound imaging of focal liver lesions with a second-generation contrast agent

For several years, the major diagnostic objective in using US contrast agents has been to detect flow in the circulation at a lower level than that otherwise possible in Doppler techniques. However, it turned out that enhanced color and power Doppler could provide fine details on small and deep vessels, but were not sensitive enough to detect contrast agents in the microcirculation. As a result, the usefulness of contrast agents in the field of liver imaging was limited to the evaluation of the vascular architecture of focal lesions. Recently, the development of new US techniques that produce images based on nonlinear acoustic effects of US interaction with microbubble contrast agents has opened new prospects for US imaging of the liver. These contrast-specific imaging techniques, in fact, can display microbubble enhancement in gray-scale, thus maximizing contrast and spatial resolution and enabling the analysis of the microcirculation. These techniques offer high sensitivity either to microbubble movement or to microbubble collapse independent of the level of the applied acoustic peak pressure. At low acoustic peak pressure levels grossly reflected by a low mechanical index (MI) the microbubble destruction can be reasonably neglected and the microbubble movement effect due to blood circulation is predominant. In contrast, when increasing the acoustic peak pressure levels (high MI), the destruction phenomena become the most important: the signal, in fact, is produced by microbubble collapse, and is related to microbubble concentration and not to blood flow velocity (1–3). We performed a pilot clinical study aimed at investigating the usefulness of both destructive (high MI) and non-destructive (low MI) gray-scale US techniques, in combination with a second-generation contrast agent, for the detection and characterization of focal liver lesions.

Preoperative rectal cancer staging with phased-array MR

BackgroundWe retrospectively reviewed magnetic resonance (MR) images of 96 patients with diagnosis of rectal cancer to evaluate tumour stage (T stage), involvement of mesorectal fascia (MRF), and nodal metastasis (N stage).Our gold standard was histopathology.MethodsAll studies were performed with 1.5-T MR system (Symphony; Siemens Medical System, Erlangen, Germany) by using a phased-array coil. Our population was subdivided into two groups: the first one, formed by patients at T1-T2-T3, N0, M0 stage, whose underwent MR before surgery; the second group included patients at Tx N1 M0 and T3-T4 Nx M0 stage, whose underwent preoperative MR before neoadjuvant chemoradiation therapy and again 4-6 wks after the end of the treatment for the re-staging of disease.Our gold standard was histopathology.ResultsMR showed 81% overall agreement with histological findings for T and N stage prediction; for T stage, this rate increased up to 95% for pts of group I (48/96), while for group II (48/96) it decreased to 75%.Preoperative MR prediction of histologically involved MRF resulted very accurate (sensitivity 100%; specificity 100%) also after chemoradiation (sensitivity 100%; specificity 67%).ConclusionsPhased-array MRI was able to clearly estimate the entire mesorectal fat and surrounding pelvic structures resulting the ideal technique for local preoperative rectal cancer staging.

CT Colonography: Role of a second reader CAD paradigm in the initial training of radiologists

PURPOSE To evaluate the influence of CAD for the evaluation of CT colonography (CTC) datasets by inexperienced readers during the attendance of a dedicated hands-on training course. METHOD AND MATERIALS Twenty-seven radiologists inexperienced in CTC (11 with no CTC training at all, 16 having previously reviewed no more than 10 CTC cases overall) attended a hands-on training course based on direct teaching on fifteen workstations (four Advantage Windows 4.4 with Colon VCAR software, GE; six CADCOLON, Im3D; five ColonScreen (Toshiba/Voxar) with ColonCAD™ API, Medicsight). During the course, readers were instructed to analyze 26 CTC cases including 38 colonic lesions obtained through low-dose MDCT acquisitions, consisting of 12 polyps sized less than 6 mm, 9 polyps sized between 6 and 10 mm, 12 polyps sized between 11 mm and 30 mm, and 5 colonic masses sized>3 cm. CTC images were reviewed by each reader both in 2D and 3D mode, respectively by direct evaluation of native axial images and MPR reconstructions, and virtual endoscopy or dissected views. Each reader had 15 min time for assessing each dataset without CAD, after which results were compared with those provided by CAD software. Global rater sensitivity for each lesion size before and after CAD usage was compared by means of two-tailed Students t test, while sensitivity of each single reader before and after CAD usage was assessed with the McNemar test. RESULTS For lesions sized<6 mm, global rater sensitivity was 0.1852±0.1656 (mean±SD) before CAD-assisted reading and 0.2345±0.1761 after CAD (p=0.0018). For lesions sized 6-9 mm, sensitivity was 0.2870±0.1016 before CAD-assisted reading and 0.3117±0.1099 after CAD (p=0.0027). For lesions sized 10-30 mm, sensitivity was 0.5308±0.2120 before CAD-assisted reading and 0.5637±0.2133 after CAD (p=0.0086), while for lesions sized>30 mm, sensitivity before CAD-assisted reading was 0.3556±0.3105 and did not change after CAD usage (p=1). Sensitivity of each single rater did not significantly differ before and after CAD for any lesion size category (McNemar test, p>0.05). Specificity was not significantly different before and after CAD for any lesion size (>96% for all size categories). CONCLUSION CAD usage led to increased overall sensitivity of inexperienced readers for all polyps sizes, except for lesions>30 mm, but sensitivity of individual raters was not significantly higher compared with CAD-unassisted reading.

Value of image fusion in the staging of prostatic carcinoma.

Purpose.We assessed the value of image fusion in the staging of prostatic cancer in a series of 32 patients who underwent preoperative evaluation with transrectal colour-Doppler ultrasonography (TRUS) and magnetic resonance imaging (MRI).Materials and methods.Colour-Doppler TRUS exams were performed using a 7.5-MHz biplanar probe. MRI exams were done with a scanner operating at 1.5 Tesla (T) using an endorectal coil. All patients underwent radical prostatectomy within 2 weeks from the imaging assessment. Whole-mount sections were prepared from the surgical specimens and were subsequently digitised by using a high-resolution scanner. The Digital Imaging and Communications in Medicine (DICOM) TRUS and MR images as well as the digitised pathological images were transferred to a graphic workstation to perform image fusion.Results.Image fusion was technically possible in 25/32 cases in which axial TRUS images were available. The following fusion images were obtained: TRUS + pathological sections; MRI + pathological sections; TRUS + MRI + pathological sections. The final pathological staging concerning the T status was: four pT2b, fourteen pT2c, three pT3a and four pT3b. The three types of image fusion led to the following results: TRUS + pathological sections, correct staging in 20/25 cases (accuracy 80%); MRI + pathological sections, correct staging in 22/25 cases (accuracy 88%); TRUS + MRI + pathological sections, correct staging in 23/25 cases (accuracy 92%).Conclusions.Our study suggests that by using image fusion between colour-Doppler TRUS and endorectal MRI, it is possible to improve the accuracy of pathological staging in patients who are candidates for radical prostatectomy.

Anatomical localization of deep infiltrating endometriosis: 3D MRI reconstructions

PurposeThe goal of this study was to determine the accuracy of three-dimensional (3D) MRI reconstructions obtained with segmentation technique in the preoperative assessment of deep infiltrating endometriosis (DIE) and in particular to evaluate rectosigmoid and bladder wall involvement.Materials and methodsInstitutional review board approval for this study was obtained, and each patient gave written informed consent. Fifty-seven consecutive patients with diagnosis of DIE who had undergone pelvic MRI at 1.5 T before surgery between 2007 and 2011, were retrospectively evaluated and 3D post-processed in order to obtain a detailed mapping of DIE. A blinded reader interpreted images. MRI results were compared with surgical findings and were scored by using a four-point scale (0_3 score).Results36/57 patients with symptomatic DIE underwent surgery: 18/36 had endometriotic nodules infiltrating the rectouterine pouch, 12/36 the vesicouterine pouch, and 6/36 the rectovaginal pouch. The sensitivity of MRI and 3D MRI vs. surgery was, respectively, 64% vs. 83%; diagnostic accuracy of 3D MRI respect to MRI alone was 86% vs. 67% for localization; 86% vs. 67% for dimension; 79% vs. 58% for rectosigmoid infiltration; 92% vs. 75% for bladder infiltration.ConclusionsIn this preliminary study, 3D MRI reconstructions obtained with semi-automatic method of segmentation provided encouraging results for staging DIE preoperatively. In fact, the addition of 3D MRI reconstructions improved diagnostic accuracy and staging of DIE providing the exact volume of the lesions and enabling a precise mapping of these before surgery.

Ileal invaginated Meckel's diverticulum: Imaging diagnosis (2004:9b)

We describe an uncommon case of severe anemia in an adult man. The patient was evaluated with esophagogastroduodenoscopy, colonoscopy, barium enema and abdominal US, which all proved normal. Abdominal CT showed a nonspecific intraluminal mass. Small-bowel follow-through revealed a polypoid mass with a club-like appearance typical for an invaginated Meckels diverticulum. Our diagnosis was confirmed by surgery.

Deep endometriosis with pericolic lymph node involvement: A case report and literature review

Deep infiltrating endometriosis is an often-painful disorder affecting women during their reproductive years that usually involves the structures of the pelvis and frequently the gastrointestinal tract. We present the case of a 37-year-old female patient with an endometrial growth on the sigmoid colon wall causing pain, diarrhea and the presence of blood in the feces. The histology of the removed specimen also revealed the involvement of the utero-vesical fold, the recto-vaginal septum and a pericolic lymph node, which are all quite uncommon findings. To identify the endometrial cells, we performed immunohistochemical staining for CD10 and the estrogen and progesterone receptors.

Inflammatory Bowel Diseases

The term inflammatory bowel disease covers a group of disorders of the gastrointestinal tract caused by an immune reaction to the intestinal wall, and the two major types are ulcerative colitis and Crohn’s disease. Ulcerative colitis is limited to the large bowel with primary mucosal involvement; meanwhile, in Crohn’s disease, any part of the gastrointestinal tract may be involved, with transmural lesions. Both are intermittent diseases, with periods of exacerbated symptoms, and periods that are relatively symptom-free.

I mezzi di contrasto in TC

Lo sviluppo dei mezzi di contrasto e iniziato poco dopo la scoperta dei raggi X, non appena ci si rese conto che molte strutture non erano visibili sulla semplice immagine radiografica, perche caratterizzate da una scarsa differenza di densita rispetto alle strutture circostanti. Tali strutture anatomiche non sarebbero state direttamente valutabili con le tecniche radiologiche se non fosse stato possibile ottenerne una variazione artificiale della densita mediante l’introduzione nell’organismo di sostanze dotate di un’attenuazione dei fotoni X notevolmente diversa da quella dei tessuti esaminati: i mezzi di contrasto.