Prior Computed Tomography Scan Research Articles

Abstract 15627: Inferior Vena Cava Filter Strut Fracture and Migration to the Right Ventricle in Post-COVID Patient With Intractable Cough

Background: Inferior vena cava (IVC) filter fracture and migration of the fractured strut is a rare but potentially dangerous complication. We report a case of fractured IVC strut migrated to the right ventricle (RV) in a patient who was evaluated for persistent cough. Clinical Case: A 69-year-old male presented to his primary care physician for the evaluation of intractable cough and shortness of breath. Past medical history was significant for recurrent unprovoked deep vein thromboses treated with an IVC filter 15 years ago. He had COVID19 infection six months prior to current presentation. A computed tomography (CT) scan of the chest was ordered to screen for underlying pulmonary disease. CT scan showed no pulmonary process, but revealed a linear radiopaque foreign body in the RV of the heart. His cough was considered to be a sequela of his prior COIVD19 infection. Decision-making: To better characterize this foreign body in RV, a transesophageal echocardiogram was performed. This showed a prominent linear echo density on the tricuspid valve chord in the RV. On careful review of the CT scan of the chest and comparison with prior CT scans, it was found that one of the IVC filter strut at 9 o’ clock position was missing. The ‘foreign body’ in the RV had the same size as the remaining struts of the IVC filter. Given that the patient did not have any symptoms or complications from the incidentally found fractured strut, decision was made to not retrieve it with a percutaneous or surgical intervention. Conclusion: Significant variations in the intra-abdominal pressure may contribute to metal fatigue potentially leading to IVC filter strut fracture and migration to the RV. This underscores the importance of timely removal of IVC filters. Uncomplicated migrated IVC filter struts may be left unretrieved and patients can be followed clinically.

P-BN30 Retroperitoneal biloma: a case report of spontaneous retroperitoneal bike leak and collection

Abstract Background Retroperitoneal biloma is a rare complication of gallstone disease. Only a handful of cases have been reported in the literature with various mechanisms postulated. Here, we report a case of spontaneous retroperitoneal biloma arising from gallbladder perforation. Methods An 87-year-old female patient presented with right upper quadrant pain in the context of known gallstone disease. Inflammatory markers and liver function tests were deranged. Cross sectional imaging found acute cholecystitis and a gallbadder neck perforation with an impacted 2cm proximal common bile duct (CBD) stone. A cholecystostomy was placed and she improved clinically. However, inflammatory markers remained high, and a subsequent computed tomography (CT) found a large collection in the retroperitoneum. Results The retroperitoneal collection measured 14cm x 7cm, and there had been evidence on prior CT scans of retroperitoneal inflammation. It was urgently drained under ultrasound guidance and found to contain bilious content. Subsequent endoscopic retrograde cholangiopancreatography (ERCP) was unable to retrieve the CBD stone, but left stents either side of the stone. The patient clinically and biochemically improved. She was discharged and had an elective ERCP, which successfully retrieved the stone, with a plan for urgent elective laparoscopic cholecystectomy. Conclusions Here, we report an interesting case of retroperitoneal biloma successfully managed with ultrasound-guided drainage. Perforation of the distal CBD can result in retroperitoneal bile leak, but the proximal CBD stone in this case would have likely prevented passage of bile. A more likely cause is adhesion of the gallbladder neck to the posterior parietal peritoneum due to chronic inflammation, with subsequent perforation and release of bile into the retroperitoneum. This has previously been described in the literature. Regardless of mechanism, knowledge of the potential for this rare complication is important for anticipating and appropriately managing complications of gallbladder perforation.

Full field-of-view, high-resolution, photon-counting detector CT: technical assessment and initial patient experience

We report a comprehensive evaluation of a full field-of-view (FOV) photon-counting detector (PCD) computed tomography (CT) system using phantoms, and qualitatively assess image quality in patient examples. A whole-body PCD-CT system with 50 cm FOV, 5.76 cm z-detector coverage and two acquisition modes (standard: 144 × 0.4 mm collimation and ultra-high resolution (UHR): 120 × 0.2 mm collimation) was used in this study. Phantoms were scanned to assess image uniformity, CT number accuracy, noise power spectrum, spatial resolution, material decomposition and virtual monoenergetic imaging (VMI) performance. Four patients were scanned on the PCD-CT system with matched or lower radiation dose than their prior clinical CT scans performed using energy-integrating detector (EID) CT, and the potential clinical impact of PCD-CT was qualitatively evaluated. Phantom results showed water CT numbers within ±5 HU, and image uniformity measured between peripheral and central regions-of-interests to be within ±5 HU. For the UHR mode using a dedicated sharp kernel, the cut-off spatial frequency was 40 line-pairs cm−1, which corresponds to a 125 μm limiting in-plane spatial resolution. The full-width-at-half-maximum for the section sensitivity profile was 0.33 mm for the smallest slice thickness (0.2 mm) using the UHR mode. Material decomposition in a multi-energy CT phantom showed accurate material classification, with a root-mean-squared-error of 0.3 mg cc−1 for iodine concentrations (2–15 mg cc−1) and 14.2 mg cc−1 for hydroxyapatite concentrations (200 and 400 mg cc−1). The average percent error for CT numbers corresponding to the iodine concentrations in VMI (40–70 keV) was 2.75%. Patient PCD-CT images demonstrated better delineation of anatomy for chest and temporal bone exams performed with the UHR mode, which allowed the use of very sharp kernels not possible with EID-CT. VMI and virtual non-contrast images generated from a patient head CT angiography exam using the standard acquisition mode demonstrated the multi-energy capability of the PCD-CT system.

Dosimetry Comparison of Palliative Radiation Plans Generated From Available Diagnostic CT Images Versus Dedicated CT Simulation for Inpatients.

IntroductionThe morbidity sequelae of advanced cancer are often irreversible. Early palliative radiation can prevent, delay, and even improve these consequences. Treatment may be delayed due to a packed computed tomography (CT) simulation schedule or other logistics, including the cost and burden of arranging ambulance transportation when radiation centers are off-site.ObjectivesThe primary objective was to determine the feasibility of using a recent diagnostic CT scan in lieu of a dedicated simulation CT to generate an adequate plan without sacrificing dosimetric goals and subsequent efficacy or tolerability. Secondary objectives included how much the lesion has grown, and how much earlier treatment could start if planned on a diagnostic CT scan.Materials/MethodsFor each inpatient treated with palliative radiation, a prior recent diagnostic CT scan was imported into the RayStation (RaySearch Laboratories, Stockholm, Sweden) planning system. From these diagnostic scans, planning treatment volumes (PTV) and organs at risk (OAR) were contoured using the same technique as the patient’s actual treatment. The primary outcome was to compare both the PTV coverage and OAR dose between the plan generated from the diagnostic CT compared to that from the simulation CT. Our secondary outcomes include the mean time between CT simulation and first treatment, change in tumor volume between diagnostic scan and CT simulation, and the hottest 1% of each plan (D1).ResultsBetween May and August 2019, a total of 22 inpatients were treated palliatively. Of those 22 patients, 10 patients (ages 32-92 years, median 64.5 years, 50% spine) met study criteria and had a diagnostic CT scan that was obtained within 14 days of simulation CT that was also compatible with our planning software. In the plans that were delivered, a mean of 98.8% (range 94.4-100%) of PTV was covered by at least 95% prescription dose. In the diagnostic CT plans, a mean of 95.4% (range 84.5-100%) of PTV was covered by at least 95% prescription dose. The difference between plans trended towards significance (p=0.061). When looking at patients receiving treatment to the spine or having a diagnostic CT within four days of the simulation CT, there was no statistically significant difference between the two plans (p=0.032 and 0.030, respectively). The OARs received, on average, 1.4% less mean radiation dose in the hypothetical plans (p=0.911). All OAR constraints were met in both groups. The mean time between diagnostic CT and CT simulation was 5.9 days and between CT simulation and first treatment was 1.9 days (range 0-5 days). The mean change in tumor volume was 22.64% smaller in the diagnostic CT scan plan. The D1 was an average 1% hotter in the hypothetical plans (p=0.16).ConclusionIn hospitalized patients with an indication for palliative radiation, treatment planning on a pre-existing recent diagnostic CT scan produces comparable dose distributions without increases in dose to OARs when compared to the use of CT simulation scans, particularly for the treatment of the spine or when a very recent diagnostic CT is available. Bypassing CT simulation in select cases allows for earlier delivery of radiation with less patient and logistical burden. In combination with daily image guidance, this may translate to more timely delivery of radiation, less cost and burden to critically ill patients, and improved palliative benefit.

Cross-sectional analysis of follow-up chest MRI and chest CT scans in patients previously affected by COVID-19

PurposeThe aim of the study was to prospectively evaluate the agreement between chest magnetic resonance imaging (MRI) and computed tomography (CT) and to assess the diagnostic performance of chest MRI relative to that of CT during the follow-up of patients recovered from coronavirus disease 2019.Materials and methodsFifty-two patients underwent both follow-up chest CT and MRI scans, evaluated for ground-glass opacities (GGOs), consolidation, interlobular septal thickening, fibrosis, pleural indentation, vessel enlargement, bronchiolar ectasia, and changes compared to prior CT scans. DWI/ADC was evaluated for signal abnormalities suspicious for inflammation. Agreement between CT and MRI was assessed with Cohen’s k and weighted k. Measures of diagnostic accuracy of MRI were calculated.ResultsThe agreement between CT and MRI was almost perfect for consolidation (k = 1.00) and change from prior CT (k = 0.857); substantial for predominant pattern (k = 0.764) and interlobular septal thickening (k = 0.734); and poor for GGOs (k = 0.339), fibrosis (k = 0.224), pleural indentation (k = 0.231), and vessel enlargement (k = 0.339). Meanwhile, the sensitivity of MRI was high for GGOs (1.00), interlobular septal thickening (1.00), and consolidation (1.00) but poor for fibrotic changes (0.18), pleural indentation (0.23), and vessel enlargement (0.50) and the specificity was overall high. DWI was positive in 46.0% of cases.ConclusionsThe agreement between MRI and CT was overall good. MRI was very sensitive for GGOs, consolidation and interlobular septal thickening and overall specific for most findings. DWI could be a reputable imaging biomarker of inflammatory activity.

Pancreatic Fat Infiltration Is Associated with a Higher Risk of Pancreatic Ductal Adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC) has a poor survival rate, partly due to delayed diagnosis. Identifying high-risk individuals could lead to early detection and improve survival. A number of risk factors such as alcohol consumption and metabolic syndrome are associated with fatty infiltration of the pancreas. Experimental models show that a fatty pancreas promotes tissue inflammation and fibrosis, which could promote PDAC. Methods: We conducted a case-control study in a single-university tertiary hospital. Sixty-eight PDAC cases with recent non-contrast computed tomography (CT) and 235 controls were studied. The controls had no history of malignancy and underwent CT colonography for cancer screening in the same period. Pancreatic fat was estimated by calculating pancreatic (P) attenuation, corrected to splenic (S) attenuation, measured in three 1.0-cm² regions of the pancreas. The P.S100 value calculated was used to estimate fatty infiltration of the pancreas (FIP), with a lower P.S100 representing a higher FIP. Results: The PDAC patients had a lower BMI and a higher rate of type 2 diabetes mellitus. The P.S100 was lower in cases than in controls (86.452 vs. 92.414, p = 4.016e-06), suggesting that FIP is higher with PDAC. The risk of developing PDAC steadily increased significantly for the quartiles with a higher FIP compared to the low FIP quartile. No correlation between BMI and FIP (r = –0.1031179; 95% confidence interval [CI] –0.22267106 to 0.01949092) was found. Adjusting for confounders (age, sex, BMI, and DM), the risk of developing PDAC according to the FIP was estimated to be 3.75 (95% CI 1.9234408–7.993337; p = 0.000171). FIP was stable before and after the diagnosis of PDAC in 9 cases with prior CT scans when no pancreatic tumor was identifiable. Conclusion: Fatty pancreas is associated with an increased risk of pancreatic cancer. Once confirmed in larger-scale studies, these findings could help to identify at-risk individuals, particularly in high-risk groups such as chronic alcohol consumers

Primary retroperitoneal mucinous cystadenoma in a male patient: a case report

Primary retroperitoneal mucinous cystic neoplasms are very rare, especially in men. To our knowledge, only 13 cases of such neoplasms have been reported in men to date. The most common type is the primary retroperitoneal mucinous cystadenoma, which almost invariably affects females. Most patients present with non-specific symptoms. In this case report, we will describe a case of a 53 year old male patient who presented with raised CEA tumour marker and vague right sided abdominal discomfort. A computed tomography (CT) scan was performed, which revealed a 4.9 × 4.7 × 7.5 cm lobulated retroperitoneal cystic lesion abutting the posterior wall of the mid ascending colon. A laparoscopic excision was eventually performed with complete removal of the retroperitoneal cystic lesion. Subsequent histological assessment confirmed the diagnosis of a primary retroperitoneal mucinous cystadenoma with borderline malignancy. On comparison with a prior CT scan performed about seven and a half years earlier, we managed to derive a doubling rate of about 626 days, which is the first reported case in English literature to document the growth rate of such a tumour. The patient has since been discharged well, with no evidence of tumour recurrence on an interval CT scan.

Clinical profile of patients of acute aortic dissection presenting to the ED without chest pain

The aim of the study is to present the results in a consecutive series of patients affected by aortic abdominal aneurysm and to underline the aneurysmal growth and evolution in oncological patients submitted to dedicated oncological medical therapy.Between January 2010 and June 2016 we treated in our center 19 patients for coexisting aortic aneurysms (>3 cm) and malignancy. We observed patients undergoing oncological treatment and patients who did not undergo medical treatment. We studied computed tomography (CT) scan at the time when patients were addressed at our follow-up or treatment and we analyzed retrospectively prior CT scan at 6 and 12 months.Among those 19 patients, 7 patients were affected by colorectal cancer (36.8%), 6 by urinary tract cancer (31.6%), 4 by lymphoma (21%), and 2 by lung cancer (10.6%). In 8 patients who did not undergo oncological therapy, we did not observe any aortic growth; instead, in other 4 patients who underwent oncological medical therapy (3 abdominal aortic aneurysms and 1 thoracic aneurysm), we observed a mean sac growth of 2.9 cm in 6 months with 2 cases of aortic rupture treated in urgent fashion. The treatment was open surgery in 2 cases and endovascular in other cases.We observed that oncological drugs may play a role in aneurysm growth. Few case reports are found in the literature and more evidences are to be found. Those information may influence intention-to-treat small aneurysms in short life expectancy patients.

Evaluation of Small Adrenal Incidental Nodules: Is Imaging Follow-Up Necessary?

Low incidence of adrenal cortical carcinoma in the general adult population has prompted a reevaluation of current protocol for the assessment of adrenal incidentalomas. To determine whether follow-up imaging for small (≤ 4 cm) incidental adrenal nodules is necessary for patients without known cancer. We performed a retrospective analysis of all patients found to have an incidental adrenal nodule on abdominal computed tomography (CT) scan during a 27-month period. The electronic medical record was reviewed to determine clinical outcomes in all patients with a minimum of 3 years of follow-up (mean follow-up = 6.7 years). Patients with a known primary cancer were excluded from the analysis unless they had a prior CT scan that documented an incidental adrenal nodule. Unenhanced CT attenuation was measured for all nodules, if available. A total of 392 patients with an incidental adrenal nodule had a mean (standard deviation [SD]) clinical follow-up of 6.7 (2.7) years. There were 200 men and 192 women with a mean (SD) age of 66.0 (13.2) years. None of these patients developed primary adrenocortical carcinoma during the follow-up period.Two hundred forty of these patients also had a minimum 3 years of imaging follow-up (mean [SD], 6.4 [2.4] years; range, 3.1-13.6 years). There were 173 left-sided and 91 right-sided nodules on index CT scan. There was no significant difference in the mean (SD) rate of growth between left- and right-sided nodules (0.1 [0.8] mm/year vs 0.1 [0.8] mm/year, p = 0.58). Mean unenhanced CT attenuation of adrenal nodules did not affect the likelihood of adrenal malignancy during follow-up. Patients with small incidental adrenal nodules do not require additional imaging to exclude the possibility of adrenocortical carcinoma.

Feasibility of Ultrasound Imaging of Osteochondral Defects in the Ankle: A Clinical Pilot Study

Talar osteochondral defects (OCDs) are imaged using magnetic resonance imaging (MRI) or computed tomography (CT). For extensive follow-up, ultrasound might be a fast, non-invasive alternative that images both bone and cartilage. In this study the potential of ultrasound, as compared with CT, in the imaging and grading of OCDs is explored. On the basis of prior CT scans, nine ankles of patients without OCDs and nine ankles of patients with anterocentral OCDs were selected and classified using the Loomer CT classification. A blinded expert skeletal radiologist imaged all ankles with ultrasound and recorded the presence of OCDs. Similarly to CT, ultrasound revealed typical morphologic OCD features, for example, cortex irregularities and loose fragments. Cartilage disruptions, Loomer grades IV (displaced fragment) and V (cyst with fibrous roof), were visible as well. This study encourages further research on the use of ultrasound as a follow-up imaging modality for OCDs located anteriorly or centrally on the talar dome.

Utility of Repeated Abdominal CT Scans After Prior Negative CT Scans in Patients Presenting to ER with Nontraumatic Abdominal Pain

The purpose of this study was to analyze diagnostic yield of repeat computed tomography (CT) after negative initial CT versus yield of initial CT in patients presenting repeatedly to emergency room (ER) for nontraumatic abdominal pain. Medical costs and radiation exposure from repeat CT could be reduced if repeat CT after negative initial CT has a low diagnostic yield. Patients included consecutive adults presenting to William Beaumont Hospital, from 2007 to 2010, undergoing abdominal CT for nontraumatic abdominal pain retrospectively identified by medical diagnostic and CT procedural codes. Exclusion criteria were prior abdominal trauma, recent abdominal surgery, and known chronic gastrointestinal disease. The CT was labeled "positive" if findings explained patient's abdominal pain or was clinically significant. Positivity rate was compared for repeat versus initial CT. Among 200 consecutive patients undergoing (659) multiple CTs (mean age = 45.7 years, 74 % female), positivity rate for initial CT (22.5 %) was significantly higher than positivity rates for CT#2 (8.4 %, p = 0.002), for CT#3 (4.9 %, p = 0.005), and for CT ≥ #4 (5.9 %, p = 0.006). Generally, CT positivity rate declined with increasing number of prior negative CTs. CT positivity rate was significantly higher in 100 patients undergoing single CT versus 155 patients undergoing repeat CTs (46.5 vs. 6.5 %, p = 0.0001). Positive repeat CT findings included intestinal mural thickening/mass (7), colitis (5), appendicitis (4), and other (14). Among 15 analyzed clinical parameters, two significantly predicted repeat CT positivity, namely, leukocytosis (p = 0.03) and APACHE-II-score >5 (p = 0.01). Repeat CTs constituted 47 % of all CTs. Repeat abdominal CT after initially negative CT(s) performed for nontraumatic abdominal pain has a low diagnostic yield. Leukocytosis and APACHE-II score might help predict CT scan positivity. Data suggest restricted abdominal CT utilization in ER patients with multiple prior negative CTs. Findings warrant confirmation in prospective studies.

2297 SUBMILISIEVERT COMPUTED TOMOGRAPHY FOR THE EVALUATION OF UROLITHIASIS

You have accessJournal of UrologyStone Disease: Basic Research II1 Apr 20122297 SUBMILISIEVERT COMPUTED TOMOGRAPHY FOR THE EVALUATION OF UROLITHIASIS Brian Eisner, Naveen Kulkarni, Daniella Pinho, Raul Uppot, Guarav Desai, and Dushyant Sahani Brian EisnerBrian Eisner Boston, MA More articles by this author , Naveen KulkarniNaveen Kulkarni Boston, MA More articles by this author , Daniella PinhoDaniella Pinho Boston, MA More articles by this author , Raul UppotRaul Uppot Boston, MA More articles by this author , Guarav DesaiGuarav Desai Boston, MA More articles by this author , and Dushyant SahaniDushyant Sahani Boston, MA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2477AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES We evaluated feasibility of submillisievert computed tomography (CT) examinations reconstructed with iterative reconstruction (IR) techniques in patients with urolithiasis. METHODS 26 patients (mean age-38 yrs) with diagnosed urolithiasis, treated and on follow up underwent submillisievert dose unenhanced scan on 64 MDCT (Discovery CT750 HDCT, GE Healthcare) and 128 MDCT (Somatom Definition Flash, Siemens Health care). The scan protocol included 80 kV, auto mA 75-150 or Ref mA - 80, slice thickness 5mm for < 200 lbs and 100 kV, auto mA 75-150 or Ref mA - 80, slice thickness 5mm for > 200 lbs. Images were reconstructed using filtered back projection (FBP) and IR [ASIR(GE) 60% & 80% and IRIS (Siemens)]. All images were reviewed for image quality (scale 1-5), noise (scale 1-3), number and size of calculi and reader confidence on PACS work station. Comparison was made with the prior low dose FBP baseline CT scan. RESULTS All 34 stones mean size (6.4mm, range 4-15 mm) was confidently diagnosed by two readers, yielding 100% sensitivity and accuracy. In 8 patients, stones had passed/resolved after treatment. In giving a differential diagnosis IR images were rated better than FBP (2.8 vs 1.7). The mean CTDI, DLP and mSv for submillisievert protocol was 1.2, 65.3 and 0.86 in comparison to 10.6, 363.4, and 5.4 for our baseline low dose exam with 82-88% dose reduction (p-0.0013). CONCLUSIONS Submillisievert unenhanced CT is a clinically feasible for diagnosis of urolithiasis with 82-88% dose reduction compared with standard non-contrast CT. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e927 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Brian Eisner Boston, MA More articles by this author Naveen Kulkarni Boston, MA More articles by this author Daniella Pinho Boston, MA More articles by this author Raul Uppot Boston, MA More articles by this author Guarav Desai Boston, MA More articles by this author Dushyant Sahani Boston, MA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Computed Tomography Appearance of Early Radiation Injury to the Lung: Correlation With Clinical and Dosimetric Factors

To systematically assess the spectrum of radiologic changes in the lung after radiation therapy for non-small-cell lung cancer. We reviewed the cases of 146 patients treated with radical radiotherapy at our institution. All patients had computed tomography (CT) scans performed 3 months after completion of therapy. Radiographic appearances were categorized using a standard grading system. The association of these abnormalities with pretreatment factors and clinical radiation pneumonitis (RP) was investigated. New intrapulmonary abnormalities were seen in 92 patients (63%). These were ground-glass opacity in 16 (11%), patchy consolidation in 19 (13%), and diffuse consolidation in 57 (39%). Twenty-five patients (17%) developed clinical symptoms of RP. Although 80% of the patients with RP had areas of consolidation seen on the posttreatment CT scan, the majority (74%) of patients with such radiographic changes were asymptomatic. For patients with lung infiltrates, the minimum isodose encompassing the volume of radiologic abnormality was usually ≥27 Gy. Traditional dose-volume metrics, pulmonary function tests, and the coadministration of angiotensin converting enzyme inhibitors (ACE-I) were all strongly correlated with the presence of radiologic injury on univariate analysis (p≤0.002). There was also an inverse correlation between prior smoking history and CT scan changes (p=0.02). On multivariate analysis, dosimetric parameters and the use of ACE-I retained significance (p=0.005). Our findings suggest that there is substantial interindividual variation in lung radiosensitivity. ACE-I prevented the radiologic changes seen after high-dose radiation therapy, and their role as radioprotectants warrants further investigation.

How Often are Previously Undetected Radiographic Abnormalities Detected at the Time of CT Simulation for Breast Cancer Patients?

In most institutions, planning computed tomography (CT) scans are not interpreted by diagnostic radiologists. The purpose of this analysis was to determine the percentage of cases in which a previously undetected radiographic finding was found on review of CT simulation images by diagnostic radiology. At the Henry Ford West Bloomfield Center, CT simulations are prospectively interpreted by diagnostic radiologists and a formal report is generated. CT simulation scan reports of 332 consecutive breast cancer patients from 2000 to 2006 were reviewed. The percentage of these reports in which a previously undetected abnormality was noted on the planning CT was determined. Prior and subsequent diagnostic CT scans were also reviewed to determine the clinical relevance of these diagnostic abnormalities. Of 332 patients with CT simulations for breast cancer treatment planning, 52 patients (16%) had a newly detected abnormality noted. Of these, 31 patients (or 60% of the abnormal findings) were deemed by diagnostic radiology to have potentially significant findings (e.g., "can not exclude metastatic disease"), and a follow-up CT or magnetic resonance imaging scan was recommended. Abnormalities in this category included previously undetected lung nodules, liver lesions, kidney/adrenal lesions, and sclerotic bony lesions. On follow-up, however, to date, these findings have demonstrated no clinical significance, although further follow-up is needed in many patients. In this study, a significant proportion of breast cancer patients undergoing CT planning studies were diagnosed with potential abnormalities for which follow-up was recommended by diagnostic radiology. To date, these findings have not been clinically relevant, though further follow-up is needed in many of the patients. Thus, in cases of clinical uncertainty, a diagnostic radiologist should be consulted and follow-up imaging obtained if necessary.

Torsion of Renal Transplant 10 Years After Simultaneous Kidney-Pancreas Transplantation: Imaging as a Diagnostic Tool

Renal transplant torsion around its pedicle is a rare technical complication of intraperitoneal renal transplantation. Intraperitoneal placement allows more transplant mobility, which increases the risk of torsion. The length of the vascular pedicle, excess ureteral length, and paucity of adhesion secondary to steroid administration are factors that also contribute to the abnormal mobility of the kidney (1). One of the diagnostic difficulties of renal torsion is its lack of specific clinical features. A high level of suspicion is needed to diagnose renal transplant torsion because it may mimic rejection and venous thrombosis. Therefore, imaging studies play a crucial role in renal torsion diagnosis. We report a case of a 48-year-old woman, with simultaneous kidney-pancreas transplant (SKPT), who developed torsion of the transplanted kidney 10 years after transplantation. She had SKPT in 1997 after developing end-stage renal disease secondary to type 1 diabetes mellitus. She was on prednisone, cyclosporine, and mycophenolic acid. Her baseline serum creatinine level was 1.1 mg/dL. Ten years later, she presented with a 3 days history of nausea, vomiting, loose stool, and anuria. On physical examination, she was markedly hypotensive and severely dehydrated, and she had mild left lower quadrant abdominal tenderness. On admission, her serum creatinine level was 6.2 mg/dL, blood glucose 93 mg/dL, serum amylase 38 mg/dL, and a trough cyclosporine was 81 ng/mL. A renal ultrasound scan showed mild pelvicaliectasis with no apparent change from a study 2 years prior. Doppler sonography showed normal arterial waveforms. Patient was aggressively resuscitated with crystalloids with no improvement in her urine output or serum creatinine level. A renal biopsy was performed, which did not show any significant pathologic changes. There was no evidence of rejection on the biopsy. A computed tomography (CT) scan of the transplanted kidney showed moderate degree of hydronephrosis and swelling around the transplanted kidney (Fig. 1b vs. a). An antegrade nephrostogram demonstrated a corkscrew-like configuration of the proximal ureter with neither opacification of the more distal ureter nor the urinary bladder. A percutaneous nephrostomy tube was placed and a copious amount of urine returned.FIGURE 1.: Pelvic renal transplant (b) shows moderate changes of hydronephrosis and dilatation of the renal collecting system compared with prior computed tomography scan (a).The patient was taken to the operating room. At laparotomy, the kidney was found twisted 180° around its pedicle with no compromise to the vascular structures. However, it was apparent that the “volvulized” transplant kidney had induced a rotational obstruction of the transplant ureter at the insertion of the bladder. The torsion was straightened, and a nephropexy of the kidney to the left colon and the anterior abdominal wall was performed. Postoperatively her serum creatinine level decreased to 0.9 mg/dL, and she was discharged home in stable condition. CT scan is more sensitive than renal ultrasound in detecting torsion of the transplanted kidney. CT imaging may show changes in renal orientation as well as secondary changes such as swelling, hydronephrosis, or abnormal enhancement (2). The most suggestive imaging sign of renal transplant torsion is the change in the axis of the transplanted kidney, which can be facilitated by comparison with baseline scans as demonstrated in our case. To our knowledge, this is the first case report of SKPT recipient who developed torsion of the transplanted kidney 10 years after transplantation. Samir Nangia Department of Internal Medicine Medical College of Wisconsin Milwaukee, WI Ehab R. Saad Division of Nephrology Medical College of Wisconsin Milwaukee, WI

Experimental demonstration of noninvasive transskull adaptive focusing based on prior computed tomography scans.

Developing minimally invasive brain surgery by high-intensity focused ultrasound beams is of great interest in cancer therapy. However, the skull induces strong aberrations both in phase and amplitude, resulting in a severe degradation of the beam shape. Thus, an efficient brain tumor therapy would require an adaptive focusing, taking into account the effects of the skull. In this paper, we will show that the acoustic properties of the skull can be deduced from high resolution CT scans and used to achieve a noninvasive adaptive focusing. Simulations have been performed with a full 3-D finite differences code, taking into account all the heterogeneities inside the skull. The set of signals to be emitted in order to focus through the skull can thus be computed. The complete adaptive focusing procedure based on prior CT scans has been experimentally validated. This could have promising applications in brain tumor hyperthermia but also in transcranial ultrasonic imaging.

Consultant views on the use of aspirin in acute cerebrovascular disease: implications for clinical trials

A questionnaire was sent to all 155 consultant physicians and geriatricians in the Yorkshire region who routinely admit patients with acute stroke in order to ascertain: (a) current opinion regarding the prescription of aspirin to patients with various manifestations of cerebrovascular disease, in particular the timing of initial treatment; and (b) the perceived role of computed tomography (CT) scans in relation to such therapy. The response rate was 81% (126/155). Aspirin was reported to be prescribed routinely by 75% (95/126) of physicians for patients with completed stroke. Amongst those prescribing aspirin, treatment was reported to be initiated routinely within 48 hours of the onset of symptoms by 63% (60/95). Only 10% (6/60) of these physicians reported that they would withhold aspirin therapy until the result of a cranial CT scan was known, although 43% (26/60) thought a CT scan was desirable. Our survey, which for logistical reasons is one of opinion rather than actual practice, suggests that aspirin is probably being prescribed acutely (less than 48 hours) after stroke to a significant number of patients and often without a pretreatment CT scan. As with patients who have had a CT scan, the balance of risks and benefits of this practice are unknown. We conclude that it would be ethical for acute treatment trials to allow randomization to aspirin without prior CT scan.

Small capsular hemorrhages. Clinical-computed tomographic correlations.

Ten patients' hemorrhagic capsular lesions were detected by computed tomography (CT). Nine of these ten patients had systemic arterial hypertension. Two patients had prior transient ischemic episodes that were of the same nature and suggested the same vascular territory as the subsequent capsular hemorrhage. All of the patients had the sudden onset of maximal neurologic deficit and none showed progressive worsening. Seven patients had pure motor hemiparesis and three had motor weakness with mild sensory impairment. The CT showed capsular hemorrhage in all cases without extension into the thalamus or basal ganglia. None of the hemorrhages caused mass effect or showed surrounding hypodense rim. In nine cases there was a rapid and complete neurologic improvement and in only one case did the patient show mild residual neurologic deficit. These ten cases emphasize the potential dangers of anticoagulation in patients who have not had a prior CT scan.