Faisal Khosa

Ipilimumab and Stereotactic Radiosurgery Versus Stereotactic Radiosurgery Alone for Newly Diagnosed Melanoma Brain Metastases.

Background: We compared the safety and efficacy of ipilimumab and stereotactic radiosurgery (SRS) to SRS alone for newly diagnosed melanoma brain metastases (MBM). Materials and Methods: We reviewed records of newly diagnosed MBM patients treated with SRS from 2009 to 2013. The primary endpoint of overall survival (OS), and secondary endpoints of local control, distant intracranial failure, and radiation necrosis were compared using Kaplan-Meier method. Univariate and multivariate analysis were performed using the Cox proportional hazards method. Results: Fifty-four consecutive MBM patients were identified, with 20 (37.0%) receiving ipilimumab within 4 months of SRS. Ipilimumab-treated and non-ipilimumab–treated patients had similar baseline characteristics. No difference in symptomatic radiation necrosis or hemorrhage was identified between cohorts. Compared with patients in the nonipilimumab group, 1 year local control (71.4% vs. 92.3%, P=0.40) and intracranial control (12.7% vs. 29.1%, P=0.59) were also statistically similar. The ipilimumab cohort also had no difference in 1-year OS (37.1% vs. 38.5%, P=0.84). Patients administered ipilimumab within 14 days of SRS had higher 1-year (42.9%) and 2-year OS (42.9%) relative to ipilimumab delivered >14 days (33.8%, 16.9%) and SRS alone (38.5%, 25.7%) but these difference were not statistically significant. Univariate analysis and multivariate analysis both confirmed single brain metastasis, controlled primary, and active systemic disease as predictors for OS. Conclusions: Use of ipilimumab within 4 months of SRS seems to be safe, with no increase in radiation necrosis or hemorrhage; however, our retrospective institutional experience with this treatment regimen was not associated with improved outcomes.

Accuracy of dual-source CT in the characterisation of non-calcified plaque: use of a colour-coded analysis compared with virtual histology intravascular ultrasound.

Non-invasive assessment of plaque volume and composition is important for risk stratification and long-term studies of plaque stabilisation. Our aim was to evaluate dual-source computed tomography (DSCT) and colour-coded analysis in the quantification and classification of coronary atheroma. DSCT and virtual histology intravascular ultrasound (IVUS-VH) were prospectively performed in 14 patients. 22 lesions were compared in terms of plaque volume, maximal per cent vessel stenosis and percentages of fatty, fibrous or calcified components. Plaque characterisation was performed with software that automatically segments luminal or outer vessel boundaries and uses CT attenuation for a colour-coded plaque analysis. Good correlation was found for per cent vessel stenosis in DSCT (53+/-13%) and IVUS (51+/-14%; r(2) = 0.70). Mean volumes for entire plaque and non-calcified atheroma were 68.5+/-33 mm(3) and 56.7+/-30 mm(3), respectively, in DSCT and 60.8+/-29 mm(3) and 55.8+/-26 mm(3), respectively, in IVUS. Mean percentages of fatty, fibrous or calcified components were 28.2+/-6%, 53.2+/-9% and 18.7+/-13%, respectively, in DSCT and 29.9+/-5%, 55.3+/-12% and 14.4+/-9%, respectively, in IVUS-VH. Significant overestimation was present for the entire plaque and the volume of calcified plaque (p = 0.03; p = 0.0004). Although good correlation with IVUS was obtained for the entire plaque (r(2) = 0.76) and non-calcified plaque volume (r(2) = 0.84), correlation proved very poor and insignificant for percentage plaque composition. Interclass correlation coefficients for non-calcified plaque volume and percentages of fatty, fibrous or calcified components were 0.99, 0.99, 0.95 and 0.98, respectively, and intraclass coefficients were 0.98, 0.93, 0.98 and 0.99, respectively. We found that using Hounsfield unit-based analysis, DSCT allows for accurate quantification of non-calcified plaque. Although percentage plaque composition proves highly reproducible, it is not correlated with IVUS-VH.

Coronary plaque quantification by voxel analysis: dual-source MDCT angiography versus intravascular sonography.

OBJECTIVE The purpose of this study was to evaluate a voxel-based analytic technique for quantification of noncalcified coronary artery plaque with intravascular sonography as a standard of reference. SUBJECTS AND METHODS Intravascular sonography and dual-source MDCT angiography prospectively performed on 12 patients resulted in identification of 20 segments containing noncalcified plaque. Four of these segments were used to establish reference measurements of 0.6-mm proximal wall thickness with a 0-HU cutoff between the epicardial fat and outer wall and an individually adjusted threshold for the interface between the wall and lumen. With these data, consecutive circular layers of the outer wall were subtracted from a 3D volume to determine the plaque plus medial layer and the actual plaque volume in the other 16 segments. Accuracy of the voxel technique was assessed by comparing the results with intravascular sonographic findings. RESULTS Both the total plaque burden (plaque plus medial layer) and the actual plaque volume had good concordance with intravascular sonographic findings (49.6 +/- 20 mm (3) vs 56.7 +/- 23.6 mm (3), p = 0.076; 26.5 +/- 14.8 mm (3) vs 30.9 +/- 15.3 mm (3), p = 0.09). Corresponding correlation coefficients were r = 0.76 and r = 0.79. The method had good reproducibility, the an intraclass correlation coefficients being 0.93 for total plaque burden and 0.90 for actual plaque volume. CONCLUSION Voxel analysis can be used for accurate and reproducible quantification not only of plaque burden but also of actual plaque volume.

Assessment of In-Stent Restenosis Using 64-MDCT: Analysis of the CORE-64 Multicenter International Trial

OBJECTIVE Evaluations of stents by MDCT from studies performed at single centers have yielded variable results with a high proportion of unassessable stents. The purpose of this study was to evaluate the accuracy of 64-MDCT angiography (MDCTA) in identifying in-stent restenosis in a multicenter trial. MATERIALS AND METHODS The Coronary Evaluation Using Multidetector Spiral Computed Tomography Angiography Using 64 Detectors (CORE-64) Multicenter Trial and Registry evaluated the accuracy of 64-MDCTA in assessing 405 patients referred for coronary angiography. A total of 75 stents in 52 patients were assessed: 48 of 75 stents (64%) in 36 of 52 patients (69%) could be evaluated. The prevalence of in-stent restenosis by quantitative coronary angiography (QCA) in this subgroup was 23% (17/75). Eighty percent of the stents were <or=3.0 mm in diameter. RESULTS The overall sensitivity, specificity, positive predictive value, and negative predictive value to detect 50% in-stent stenosis visually using MDCT compared with QCA was 33.3%, 91.7%, 57.1%, and 80.5%, respectively, with an overall accuracy of 77.1% for the 48 assessable stents. The ability to evaluate stents on MDCTA varied by stent type: Thick-strut stents such as Bx Velocity were assessable in 50% of the cases; Cypher, 62.5% of the cases; and thinner-strut stents such as Taxus, 75% of the cases. We performed quantitative assessment of in-stent contrast attenuation in Hounsfield units and correlated that value with the quantitative percentage of stenosis by QCA. The correlation coefficient between the average attenuation decrease and >or=50% stenosis by QCA was 0.25 (p=0.073). Quantitative assessment failed to improve the accuracy of MDCT over qualitative assessment. CONCLUSION The results of our study showed that 64-MDCT has poor ability to detect in-stent restenosis in small-diameter stents. Evaluability and negative predictive value were better in large-diameter stents. Thus, 64-MDCT may be appropriate for stent assessment in only selected patients.

Pictorial review: magnetic resonance imaging of colonic diverticulitis.

Magnetic resonance imaging (MRI) is rapidly emerging as a useful imaging modality for the evaluation of the gastrointestinal tract. Increasingly rapid sequences and improving hardware have significantly improved the visualisation of diseases of the colon. MRI has a major advantage over CT in that there is no ionising radiation. In our institution, MRI has increasingly been used as a complimentary imaging modality to CT in the diagnosis and evaluation of diverticulitis and its complications. In this review article, we illustrate the emerging role of MRI in the diagnosis and evaluation of colonic diverticulitis.

Anterior Versus Lateral Needle Decompression of Tension Pneumothorax: Comparison by Computed Tomography Chest Wall Measurement

OBJECTIVES Recent research describes failed needle decompression in the anterior position. It has been hypothesized that a lateral approach may be more successful. The aim of this study was to identify the optimal site for needle decompression. METHODS A retrospective study was conducted of emergency department (ED) patients who underwent computed tomography (CT) of the chest as part of their evaluation for blunt trauma. A convenience sample of 159 patients was formed by reviewing consecutive scans of eligible patients. Six measurements from the skin surface to the pleural surface were made for each patient: anterior second intercostal space, lateral fourth intercostal space, and lateral fifth intercostal space on the left and right sides. RESULTS The distance from skin to pleura at the anterior second intercostal space averaged 46.3 mm on the right and 45.2 mm on the left. The distance at the midaxillary line in the fourth intercostal space was 63.7 mm on the right and 62.1 mm on the left. In the fifth intercostal space the distance was 53.8 mm on the right and 52.9 mm on the left. The distance of the anterior approach was statistically less when compared to both intercostal spaces (p < 0.01). CONCLUSIONS With commonly available angiocatheters, the lateral approach is less likely to be successful than the anterior approach. The anterior approach may fail in many patients as well. Longer angiocatheters may increase the chances of decompression, but would also carry a higher risk of damage to surrounding vital structures.

Prospective Gating With 320-MDCT Angiography: Effect of Volume Scan Length on Radiation Dose

OBJECTIVE The purpose of this study was to evaluate the relation between radiation dose reduction and volume scan length for prospectively ECG-gated 320-MDCT angiography in the diagnosis of coronary artery disease. MATERIALS AND METHODS MDCT with prospective ECG gating was performed at one of the three volume scan lengths depending on heart length. Of 175 patients, 95 (55%; body mass index, 29 ± 5.9; mean heart rate, 59 ± 7 beats/min) underwent scanning at 160 mm; 46 (26%; body mass index, 30 ± 4.1; mean heart rate, 56 ± 5.74 beats/min) at 140 mm; and 34 (19%; body mass index, 30 ± 3.71; mean heart rate, 58 ± 3.96 beats/min) at 120 mm. RESULTS The median radiation doses were 6.5 mSv (95% CI, 6.03-7.2 mSv) for the 95 patients who underwent scanning at a volume scan length of 160 mm, 4.33 mSv (95% CI, 4.06-6.62 mSv) for the 46 patients who underwent scanning at 140 mm, and 3.47 mSv (95% CI, 3.15-3.62 mSv) for the 34 patients who underwent scanning at 120 mm. The reduction in scan length from 160 to 140 mm represented a reduction in scan length of 12.5% and the reduction to 120 mm a reduction of 25%. The median radiation dose was reduced 33% when volume scan length was changed to 140 mm and 47% when the length was changed to 120 mm. CONCLUSION Dose optimization remains an important concern in cardiac CT, and for 320-MDCT angiography, substantial dose reduction can be achieved by reducing volume scan length so that it is in concert with the patients heart length.

Prevalence of noncardiac findings on clinical cardiovascular MRI.

OBJECTIVE The purpose of our study was to determine the prevalence and significance of noncardiac findings on clinical cardiovascular MRI and to identify the cardiovascular MRI sequences that most frequently depict noncardiac findings. MATERIALS AND METHODS Images from 495 clinical cardiovascular MRI studies performed during 2006 were reviewed specifically for noncardiac findings by a cardiovascular imaging fellowship-trained radiologist without knowledge of the prior study interpretation. Noncardiac findings were classified as benign (e.g., gynecomastia), indeterminate (e.g., pleural effusion), or worrisome (e.g., lung nodule). The cardiovascular MRI sequences depicting the noncardiac finding were recorded. RESULTS On image review, 295 noncardiac findings were identified in 212 (43%) of 495 studies, including 148 benign, 133 indeterminate, and 14 worrisome noncardiac findings. Of these, 47% of indeterminate and 57% of worrisome noncardiac findings were not previously known. Cardiovascular MRI sequences that most frequently showed noncardiac findings included the single-shot fast steady-state free precession (SSFP) scout images (63% of all noncardiac findings) and axial T1-weighted fast spin-echo thoracic images (60% of all noncardiac findings), with 99% of management-changing noncardiac findings visualized on one of these two sequences. CONCLUSION Noncardiac findings on clinical cardiovascular MRI are common. Although only a small minority of studies contain management-changing noncardiac findings, the vast majority of management-changing noncardiac findings are seen on thoracic SSFP scout and axial T1-weighted thoracic fast spin-echo images.

Comparison of Radiation Dose and Image Quality: 320-MDCT Versus 64-MDCT Coronary Angiography

OBJECTIVE The purpose of this study was to compare radiation dose and image quality of 320- and 64-MDCT angiography using prospective gating. MATERIALS AND METHODS One hundred seventy-four patients underwent 320-MDCT, and 95 patients underwent 64-MDCT. The scan parameters for 320-MDCT were 120 kVp, 400 mA, and gantry rotation of 350 milliseconds; the parameters for 64-MDCT were 120 kVp, 600 mA, and gantry rotation of 350 milliseconds. Effective dose (ED) was calculated from the dose-length product and a conversion factor (k = 0.014 mSv / mGy × cm). Two observers independently assessed image quality using a 3-point scale, where 3 denotes excellent quality and 1 denotes nondiagnostic quality, using a 16-segment model. Discrepancies were settled by consensus. RESULTS The ED was significantly lower in patients undergoing 320-MDCT angiography, with a median ED of 4.4 mSv (interquartile range [IQR], 3.4-6.2 mSv), compared with 64-MDCT angiography, with a median ED of 6.2 mSv (IQR, 5.5-6.9 mSv) (p = 0.0001). In patients with a heart rate of 65 beats/min or less (92%), the median radiation dose using 320-MDCT was 4.1 mSv (IQR, 3.2-6.1 mSv), and that for 64-MDCT angiography was 6.2 mSv (IQR, 5.8-6.9 mSv) (p = 0.0001). In patients with heart rate greater than 65 beats/min (8%), the median dose was higher with 320-MDCT (8.7 mSv; IQR, 5.9-14.3 mSv) than with 64-MDCT (5.8 mSv; IQR, 5.3-6.7 mSv) (p = 0.02). Segmental image quality was significantly better for 320-MDCT (excellent or good quality, 96.66%; nondiagnostic quality, 0.1%) than for 64-MDCT angiography (excellent or good quality, 86%; nondiagnostic quality, 3.33%) (all p < 0.0001). CONCLUSION Image quality was good for both 320- and 64-MDCT angiography. Overall radiation dose was significantly lower in 320-MDCT angiography when the heart rate was 65 beats/min or less. Every effort should be made to control heart rate to minimize radiation dose.

Surgical and radiological significance of variants of Bühler's anastomotic artery: a report of three cases.

Abstract Arterial anastomoses between the celiac trunk (CT) and superior mesenteric artery (SMA) include three variants. 1) The main anastomosis is the gastroduodenal artery (GDA), which is an important branch of the common hepatic artery and anastomoses with branches of the inferior pancreatic duodenal artery, a branch of the SMA. 2) The dorsal pancreatic artery (DPA) is usually a branch of the splenic artery, which anastomoses with the anterior and posterior pancreaticoduodenal arcades via a right transverse branch of the DPA (Kirk’s arcade). 3) A less well known and rarely reported arterial anastomosis between the CT and SMA described by Buhler (1904). Three patients in whom variants of this anastomosis were present on retrospective analysis of three hundred consecutive combined CT and SMA arteriograms are reported. The embryological basis of its development, the surgical and radiological significance of the anastomotic artery are discussed.