Evaluation of the basal ganglia in neurofibromatosis type 1.

PURPOSE: Alterations of the brain microstructure and metabolism have been identified in patients with neurofibromatosis type 1 (NF1). In this study, we analyzed the basal ganglia of NF1 subjects without cognitive delay throughout a combined approach with magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) in order to better define the metabolic and microstructural characteristics of these regions and, furthermore, to verify if metabolic and microstructural abnormalities may be present in normally developed NF1 patients. METHODS: A 3-T MRI with multivoxel MRS and DTI was performed in 14 NF1 patients and eight controls. N-acetyl-aspartate (NAA), choline (Cho), creatine (Cr) values and ratios, fractional anisotropy, and apparent diffusion coefficient (ADC) were calculated, for a total of four regions of interest (ROI) for each hemisphere. RESULTS: NF1 patients, compared to healthy controls, showed (a) decreased NAA in all the four ROI, (b) increased Cho and decreased Cr in three of the four ROI, (c) decreased NAA/Cho ratio in three ROI, and (d) increased ADC in all the four ROI. A trend of increased ADC was present in three of the four ROI of NF1 patients with unidentified bright objects (UBOs) and younger than 18 years. CONCLUSION: These data confirm the presence of neuroaxonal damage with myelin disturbances in NF1 patients. We showed that metabolic and microstructural anomalies can be present in the same time in NF1 patients without developmental delay or cognitive deficits. Relations between brain anomalies, UBOs, and cognitive functions need further studies.

[MRI of extraperitoneal rectal carcinoma]. / La diagnostica per immagini del carcinoma del retto sottoperitoneale.

Last years technological developments in imaging field have made a substantial contribution to diagnosis and staging of rectal cancer. Endorectal ultrasound and MRI with endorectal coil are very useful in rectal cancer initial staging thanks to their ability to distinguish between the rectal wall layers. Major ultrasound limitations are presence of inflammations, desmoplastic reaction and small field of view which limits evaluation of perirectal invasion. MRI with phased-array coils, instead, allows depiction of mesorectum and to assess the distance between tumor and mesorectal fascia. Unfortunately CT shows low accuracy compared to MRI in local staging because it fails to distinguish the rectal wall layers. The criterion used in assessing nodal involvement remains unfortunately still the dimensional one even if new contrast media based on nano-iron particles look promising in this regard On reassessment after chemo-radiotherapy treatment, MRI proved to be a very accurate tool thanks to its ability to detect tumor downstaging, disappearance of mesorectal fascia infiltration or even to show a complete response. The presence of recurrence can be studied by contrast enhanced perfusion-MRI or with good accuracy using PET which, however, presents major technical limitations at present.

Italian multicenter, prospective study to evaluate the negative predictive value of 16- and 64-slice MDCT imaging in patients scheduled for coronary angiography (NIMISCAD-Non Invasive Multicenter Italian Study for Coronary Artery Disease).

This was a prospective, multicenter study designed to evaluate the utility of MDCT in the diagnosis of coronary artery disease (CAD) in patients scheduled for elective coronary angiography (CA) using different MDCT systems from different manufacturers. Twenty national sites prospectively enrolled 367 patients between July 2004 and June 2006. Computed tomography (CT) was performed using a standardized/optimized scan protocol for each type of MDCT system (> or =16 slices) and compared with quantitative CA performed within 2 weeks of MDCT. A total of 284 patients (81%) were studied by 16-slice MDCT systems, while 66 patients (19%) by 64-slice MDCT scanners. The primary analysis was on-site/off-site evaluation of the negative predictive value (NPV) on a per-patient basis. Secondary analyses included on-site evaluation on a per-artery and per-segment basis. On-site evaluation included 327 patients (CAD prevalence 58%). NPV, positive predictive value (PPV), sensitivity, specificity, and diagnostic accuracy (DA) were 0.91 (95% CI 0.85-0.95), 0.91 (95% CI 0.86-0.95), 0.94 (95% CI 0.89-0.97), 0.88 (95% CI 0.81-0.93), and 0.91 (95% CI 0.88-0.94), respectively. Off-site analysis included 295 patients (CAD prevalence 56%). NPV, PPV, sensitivity, specificity, and DA were 0.73 (95% CI 0.65-0.79), 0.93 (95% CI 0.87-0.97), 0.73 (95% CI 0.65-0.79), 0.93 (95% CI 0.87-0.97), and 0.82 (95% CI 0.77-0.86), respectively. The results of this study demonstrate the utility of MDCT in excluding significant CAD even when conducted by centers with varying degrees of expertise and using different MDCT machines.

Endorectal and dynamic contrast-enhanced MRI for detection of local recurrence after radical prostatectomy.

OBJECTIVE: The objective of our study was to evaluate the sensitivity and specificity of endorectal MRI combined with dynamic contrast-enhanced MRI to detect local recurrence after radical prostatectomy. MATERIALS AND METHODS: A total of 51 patients who had undergone radical prostatectomy for prostatic adenocarcinoma 10 months to 6 years before underwent a combined endorectal coil MRI and dynamic gadolinium-enhanced MRI before endorectal sonographically guided biopsy of the prostatic fossa. The MRI combined with MR dynamic imaging results were correlated with the presence of recurrence defined as a positive biopsy result or reduction in prostate-specific antigen level after radiation therapy. RESULTS: Overall data of 46 (25 recurred, 21 nonrecurred) out of 51 evaluated patients were analyzed. All recurrences showed signal enhancement after gadolinium administration and, in particular, 22 of 24 patients (91%) showed rapid and early signal enhancement. The overall sensitivity and specificity of MR dynamic imaging was higher compared with MRI alone (88%, [95% CI] 69-98% and 100%, 84-100% compared with 48%, 28-69% and 52%, 30-74%). MRI combined with dynamic imaging allowed better identification of recurrences compared with MRI alone (McNemar test: chi-square(1) = 16.67; p = < 0.0001). CONCLUSION: MRI combined with dynamic contrast-enhanced MRI showed a higher sensitivity and specificity compared with MRI alone in detecting local recurrences after radical prostatectomy.

Imaging assessment of acute pancreatitis: a review.

Acute pancreatitis is one of the more commonly encountered etiologies in the emergency setting. While in the majority of cases it is a self-limiting disease which responds rapidly to conservative management, in some cases acute pancreatitis may present with a more pronounced, sometimes dramatic, clinical picture and requires immediate medical care to avoid fatal complication. In this context, imaging plays a significant role because it enables identification of the development of the disease and local/systemic complications. The purpose of this article is to offer an overview of the disease and a spectrum of imaging findings in patients with acute pancreatitis, emphasizing the role of ultrasound, computed tomography, and magnetic resonance imaging according to the appropriate clinical context and advantages and limitations of each imaging modality are examined.

Contribution of the MR spectroscopic imaging in the diagnosis of prostate cancer in the peripheral zone.

PURPOSE: To establish the additional value of 3D magnetic resonance spectroscopy (3D-MRS) imaging to endorectal MR imaging in the diagnosis of prostrate cancer in the peripheral zone. MATERIALS AND METHODS: MR imaging and MRS imaging were performed in 79 patients with suspicion of prostate cancer on the basis of digital rectal exploration, transrectal ultrasound and PSA level. All the examinations were performed with 1.5 T MR scan using an endorectal coil (transverse and coronal FSE T2-weighted sequences, axial SE T1-weighted and PRESS 3D CSI). MR examinations have been evaluated by two Radiologists blind of the clinical data in a "per patients" analysis. MR imaging and MRS imaging findings were compared with the result of histological data from radical prostatectomy in 53 patients and biopsy in 17 patients. RESULTS: Nine patients (11.4%) were excluded because of serious artefacts in the MR spectrum. The reported values of sensitivity, specificity, PPV and NPV for MR imaging alone were respectively 84%, 50%, 76% and 63% (LR+ 1.7; LR- 0.3). Instead the reported values of sensitivity, specificity, PPV and NPV for the combination of MR imaging to MRS imaging were respectively 89%, 79%, 89% and 79% (LR+ 4.28; LR- 0.14). We found an incremental benefit of MRS imaging to MR imaging for tumour diagnosis although these results did not show statistically significant differences. CONCLUSIONS: The MRS imaging improves the accuracy of the endorectal MR imaging in the diagnosis of prostate cancer.

Intramyocardial hemorrhage: an enigma for cardiac MRI?

Cardiovascular magnetic resonance (CMR) is a useful noninvasive technique for determining the presence of microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH), frequently occurring in patients after reperfused myocardial infarction (MI). MVO, or the so-called no-reflow phenomenon, is associated with adverse ventricular remodeling and a poor prognosis during follow-up. Similarly, IMH is considered a severe damage after revascularization by percutaneous primary coronary intervention (PPCI) or fibrinolysis, which represents a worse prognosis. However, the pathophysiology of IMH is not fully understood and imaging modalities might help to better understand that phenomenon. While, during the past decade, several studies examined the distribution patterns of late gadolinium enhancement with different CMR sequences, the standardized CMR protocol for assessment of IMH is not yet well established. The aim of this review is to evaluate the available literature on this issue, with particular regard to CMR sequences. New techniques, such as positron emission tomography/magnetic resonance imaging (PET/MRI), could be useful tools to explore molecular mechanisms of the myocardial infarction healing process.

Imaging of the small bowel: Crohn's disease in paediatric patients.

In more than 20% of all patients, the Crohn's disease presents before the age of 18years. The diagnosis and management of Crohn's disease in children has changed dramatically over the last decade, mainly due to increased awareness, availability of newer diagnostic modalities such as magnetic resonance imaging (MRI) and newer, more powerful treatments such as biologics. Imaging of the small bowel is needed for diagnosis, management, follow-up and also evaluation of the disease in terms of location, extent, activity and complications. We review all the methods (barium examinations, ultrasonography, computed tomography, MR, and computed tomography- positron emission tomography) commonly used for imaging the small bowel in paediatric patients with Crohn's disease analyzing the advantages and disadvantages of each modality, with particular emphasis on MR imaging.

Multi-modal imaging technologies in cardiovascular risk assessment.

Atherosclerotic plaques can be responsible for life-threatening cardiovascular and cerebrovascular events. Some features of the plaque, such as a thin fibrous cap, large necrotic core, macrophage infiltration, neovascularization, and intraplaque hemorrhage, are associated with a major risk of such events and so their assessment is fundamental. Novel imaging techniques, each one with its own strength and drawbacks, can help in the evaluation and quantification of atherosclerosis. An analysis of the recent literature was carried out. The different techniques were compared by evaluating the accuracy of each one in the detection and assessment of the atherosclerotic plaque's features named above.

Effectiveness of clinical guidelines in the management of acute sigmoid diverticulitis. Results of a prospective diagnostic and therapeutic clinical trial.

BACKGROUND: Evidence-based criteria in the therapeutic choice for sigmoid acute diverticulitis (AD) are lacking. It is necessary to differentiate an acute episode of diverticular disease, not complicated (NCAD) and complicated (CAD) because these stages of diverticular disease needs different approach. METHODS: In a prospective study on 377 consecutive patients admitted for AD, 265 had NCAD and 112 CAD diagnosed with CT scan. Thirty-six of 265 with NCAD were operated on due to two or more previous episodes of AD. On 188 patients with NCAD followed-up, 35 had further episodes of NCAD and 2 had CAD. On 112 CAD patients, 61 had Hinchey I and were submitted to colonic resection. Twenty-three of 24 patients with Hinchey II were treated with percutaneous drainage. All Hinchey II patients were operated on. All the 13 patients with Hinchey III and IV had emergency surgery. RESULTS: We had no mortality and respectively 9.8% and 30% morbidity in Hinchey I and II patients. In Hinchey II patients percutaneous drainage was successful in 21 on 23 (91.3%). In 13 Hinchey III and IV patients the mortality rate was 25%. The comparison of CT findings and pathological results showed a sensitivity of 100% and predictive positive value of respectively 94.4, 96.7, 100 and 100% for NCAD, Hinchey I, Hinchey II and Hinchey III-IV. CONCLUSIONS: The therapeutic approach of diverticular disease needs to differentiate among an acute episode, NCAD and CAD. Evidence-based therapeutic choices can be reached only by homogeneous diagnostic criteria obtained by CT scan.

Prostate cancer: value of magnetic resonance spectroscopy 3D chemical shift imaging.

The results of recent studies of magnetic resonance imaging (MRI) combined with three-dimensional magnetic resonance spectroscopic imaging (3D-MRSI) demonstrate that the MRI/3D-MRSI exam is a unique method by which to noninvasively study the cellular metabolism and anatomy of the prostate. 3D-MRSI is emerging as the most specificity tool for non-invasive evaluation of the prostate cancer. The results of current MRI/3D-MRSI studies also provide evidence that the magnitude of metabolic changes in regions of cancer before therapy, as well as the extent of the time course of metabolic changes after therapy, may improve our understanding of cancer aggressiveness. Assessment of cancer spread outside the prostate can be significantly improved by combining MRI findings with estimates of metabolic abnormalities provided by 3D-MRSI. Clinically, combined MRI/3D-MRSI has already demonstrated a potential for improved diagnosis, staging, and treatment planning for patients with prostate cancer. This article reviewed the value of 3D-MRS imaging for the diagnosis, localization, staging, aggressiveness, and treatment planning of prostate cancer.

Steady state evaluation of aortic dissections: A feasibility study.

PURPOSE: One the main reasons for the limited use of MRI in the evaluation of aortic dissection in emergency conditions is its long execution time. The authors report their experience regarding a new MRI sequence that reduces execution time and avoids the use of contrast medium. MATERIALS AND METHODS: Eighteen haemodynamically stable patients with suspected (16 cases, 3 with confirmed diagnosis of aneurysm) or known aortic dissection (2 cases) underwent in emergency conditions 1.5T MRI with Steady-State sequence (Fast Imaging Employing Steady-State Acquisition: GRE 2D; TR 3.5, TE 1.6; Flip Angle 45, bandwidth 125, matrix 224x224, NEX 1, acquisition time per slice 7 s, thickness 6-8 mm, FOV 38; 2D-GE breath-hold sequence requiring cardiac triggering). The results obtained were compared in terms of diagnostic accuracy and execution time with those of classical MRI examination (black blood T1, FSE T2 and 3D MR-angiography) or multislice CT. RESULTS: The diagnostic accuracy of MRI, both with Steady-State sequence and the ''classical'' technique, and multislice CT in the diagnosis of dissection or aneurysm is equal (100%), whereas execution time is 6, 25 and 6 minutes, respectively. Multislice CT proved to be more accurate than Steady-State MRI in evaluating the renal parenchyma and the extension of the dissection to the renal arteries. CONCLUSIONS: The Steady-State MRI sequence provides a diagnosis of aortic dissection or aneurysmal dilatation in a short time and may represent a valuable alternative to CT in emergency settings, especially in patients with reported contraindications to iodinated contrast media.

Prostate cancer: evaluation with endorectal MR imaging and three-dimensional proton MR spectroscopic imaging.

PURPOSE: To establish the additional value of MR Spectroscopy (3D CSI MRS Three-dimensional Chemical Shift Imaging Magnetic Resonance Spectroscopy) to endorectal MR in the diagnosis and grading of prostate cancer. MATERIALS AND METHODS: MR and 3D CSI MR spectroscopy were performed in 53 patients with suspicion of prostate cancer on the basis of rectal exploration and/or transrectal ultrasound and/or the PSA levels. All the examinations were performed with a 1.5 T imager using an endorectal coil. We acquired axial and coronal T2-weighted FSE sequences, axial T1-weighted SE sequences and PRESS 3D CSI (Point Resolved Spectroscopy 3D Chemical Shift Imaging) sequences localized on the axial T2 images so as to include the prostatic gland while excluding the periprostatic fat. The MR examinations were evaluated by two radiologists unaware of the clinical data, transrectal ultrasound findings, PSA levels and histological findings. The MR and 3D CSI MRS findings were compared with the biopsy findings in 22 cases and with material obtained from laparoscopic prostatectomy in 31 cases. RESULTS: The histological examination revealed adenocarcinoma in 37 cases, prostatitis in 2 cases and no alterations in the remaining 14 cases. The morphologic MR scan showed a sensitivity of 76%, a specificity of 56%, an accuracy of 70%, a PPV of 80% and a NPV of 50%. By combining MR and 3D CSI MRS we obtained a sensitivity of 95%, a specificity of 81%, an accuracy of 91%, a PPV of 92% and a NPV of 87%. Elevated choline concentrations were found both in tumours with a low Gleason score (18 cases) and in those with a high Gleason score (19 cases); instead we found markedly reduced (n=9) or absent (n=4) citrate only in the tumours with a high Gleason score, while we found normal citrate levels in the 18 tumours with a low Gleason score. CONCLUSIONS: The 3D CSI MRS improved the reliability of endorectal MR in the diagnosis and characterisation of prostatic cancer. Moreover, the 3D CSI MRS findings demonstrated a linear correlation with tumour grade.