Follow-up Computed Tomography Studies Research Articles

Healing of Humeral Intracondylar Fissure Following Distal Ulnar Ostectomy to Treat Concurrent Elbow Joint Incongruity in a Dog

AbstractA 22-week-old female Labrador retriever presented with intermittent bilateral forelimb lameness. Computed tomography (CT) study interpretation revealed bilateral humeral intracondylar fissures (HIF) surrounded by sclerotic epiphyseal bone. Other changes included bilateral distal ulna retained cartilage core, secondary negative radioulnar incongruity (RUI), and medial coronoid process disease. The patient underwent bilateral dynamic distal ulnar ostectomies (DUO) in an attempt to address the elbow incongruity. Follow-up CT studies were performed at 2, 4, and 10 months postoperatively, which showed a bilateral improvement of elbow congruence and complete healing of HIF on the left side. The degree of congruence correction in the right elbow was possibly suboptimal, and following an initial improvement, a transcondylar screw was placed due to HIF progression.

Statin use, development of sarcopenia, and long-term survival after endovascular aortic repair

ObjectiveStatin therapy, associated with improved short-term survival after treatment of abdominal aortic aneurysms, may also predispose to muscle side effects. Evidence on statin-related sarcopenia is limited mainly to muscle function, and it is subject to several sources of bias. In the long term, postoperative development of sarcopenia is linked to mortality after endovascular repair (EVAR). We investigated statin use and long-term postoperative mortality after EVAR in relation to objective measurable markers of sarcopenia (psoas muscle surface area and density). MethodsAltogether 216 abdominal aortic aneurysm patients treated with EVAR between 2006 and 2014 at Tampere University Hospital (Finland) were retrospectively studied. Psoas muscle parameters at the L3 level were evaluated from baseline and mainly 1- to 3-year follow-up computed tomography studies. Cox regression was used to study the association between statin medication, psoas muscle changes, and all-cause mortality. ResultsThe majority of patients were male (87%), and the mean age was 77.7 years (standard deviation, 7.4). The median duration of follow-up was 6.3 years (interquartile range, 3.5) with a total mortality of 54.2% (n = 117). Regardless of a higher burden of comorbidities, statin users (n = 119) had lower mortality when compared with nonusers (multivariable hazard ratio [HR]: 0.69, 95% confidence interval: 0.48-0.99, P = .048). Furthermore, statin use was not associated with inferior muscle parameter values, and the relative change in psoas muscle area was actually lower in statin users compared with nonusers (−15.7% and −21.1%, P < .046). ConclusionsStatin use is associated with lower long-term mortality among patients undergoing EVAR without predisposing to increased sarcopenia.

Changes in tonsillolith characteristics detected in a follow-up CT study

BackgroundTonsilloliths are related clinically to halitosis and tonsillar abscess. However, the dynamics of tonsilloliths over time are unknown. The aim of the study was to evaluate change in the characteristics of tonsilloliths in a time-dependent fashion by follow-up computed tomography (CT).MethodsTonsilloliths were analyzed in 326 CT scan pair sets of initial and at least two follow-up CT examinations of patients with whole palatine tonsils and various diseases of the oral and maxillofacial regions.ResultsOver the follow-up period, 12.1% of tonsilloliths disappeared. Approximately 26.1% of tonsilloliths changed in size during follow-up, mostly increasing in size. In tonsilloliths that showed enlargement, the mean (± standard deviation) growth rate was 0.61 ± 0.41 mm per year. Approximately 37.3% of tonsilloliths changed position during the follow-up period; of these, movement was toward the respiratory tract in 92% at a mean rate of − 1.38 ± 1.59 mm per year. The calcification levels of almost all tonsilloliths showed dynamic change: HU number increased in 84.3% and decreased in 12.7% of tonsilloliths over the follow-up period. The mean rate of HU increase was 63.8 ± 96.3 HU/year, and the mean rate of HU decrease was − 38.4 ± 66.8 HU/year.ConclusionsThe calcification levels of all tonsilloliths showed dynamic fluctuation, and a tendency for excretion of tonsilloliths from the body. Their dynamics over time suggest that tonsilloliths may be in a permanently active phase which functions to remove foreign matter.

Soft tissue recurrence of an osteoid osteoma: an exceptional observation

We report the observation of the soft tissue recurrence of an osteoid osteoma (OO) in a 26-year-old man initially complaining of post-traumatic pain and swelling of the right ankle. A first arthroscopic resection was performed after the misdiagnosis of "bone irregularities" observed on computed tomography (CT) and magnetic resonance imaging (MRI). The diagnosis of OO was made by histological analysis of the resection material. The patient became asymptomatic for 5years until the symptoms progressively recurred. Follow-up MRI and CT studies demonstrated a nodular bony focus within the periarticular soft tissues of the ankle. The lesion was removed, and histological analysis confirmed the diagnosis of a whole viable OO. This observation likely resulted from the displacement of the initial lesion during the initial arthroscopic procedure. This case report highlights the possibility of recurrence of OO in the soft tissues.

Ultrashort echo time imaging of the lungs under high-frequency noninvasive ventilation: A new approach to lung imaging.

BackgroundAlthough ultrashort echo time (UTE) sequences allow excellent assessment of lung parenchyma, image quality remains lower than that of computed tomography (CT).PurposeTo investigate a high‐frequency noninvasive ventilation (HF‐NIV) technique allowing a stabilized inspiration and to compare image quality with current dedicated MR sequences.Study TypeProspective.PopulationTen healthy volunteers.Field Strength/Sequence3D radial UTE sequence at 1.5T.AssessmentUTE‐HF‐NIV sequence was compared with UTE‐free‐breathing (UTE‐FB), reconstructed at end expiration (UTE‐Exp) and average (UTE‐Avg), and breath‐hold VIBE sequences. The distance from lung apex to the dome of the right hemidiaphragm was measured. Visual assessment of the visibility and sharpness of normal anatomical structures was carried out. Dedicated software also quantitatively evaluated vessel–lung and right lung–liver interface sharpness. Apparent signal ratio (Sr) and contrast ratios (Cr) were quantitatively evaluated.Statistical TestsWilcoxon signed rank test for visual scores, paired t‐test for continuous variables, significance at P < 0.05.ResultsThe distance between apex and the right hemidiaphragmatic dome was significantly larger (P < 0.001) with UTE‐HF‐NIV compared with UTE‐FB and VIBE acquisitions. Vessel and airway visibility had identical median visual scores with all UTE methods. Median visual scores for sharpness of vessels and airways were significantly higher (P < 0.001) with HF‐NIV (vessels = 3; airways = 2) than in UTE‐FB (vessels = 2; airways = 1) and VIBE (vessels = 1; airways = 1). Software‐based vessel sharpness evaluation resulted in larger values in 8/10 volunteers with UTE‐HF‐NIV (67.3 ± 9.8) compared with UTE‐Avg (62.3 ± 12.6) but the average difference was not significant (P = 0.28). The sharpness of the lung–liver interface was significantly higher (P < 0.001) with HF‐NIV (17.3 ± 5.3) compared with UTE‐Avg (14.1 ± 3.9). Significantly higher values (P < 0.01) of Sr and Cr were observed with UTE‐HF‐NIV compared with UTE‐FB and VIBE.Data ConclusionHF‐NIV allowing acquisition at full inspiration significantly improves image quality for lung imaging. This could offer the option to alternate some follow‐up CT studies by using this technique. Level of Evidence: 2 Technical Efficacy: Stage 1J. Magn. Reson. Imaging 2019;50:1789–1797.

Liver Transplantation After Downstagings of Ruptured Advanced Hepatocellular Carcinoma in Cirrhotic Liver: Is It Advisable? A Case Report

Spontaneous rupture of hepatocellular carcinoma (HCC), defined as T4 in TNM stage by the American Joint Committee on Cancer (eighth edition), is a serious life-threatening complication. Effective treatment remains challenging because of a high 1-month mortality, a short median survival, and the potential of peritoneal metastasis. We reported on a case that received a living related donor liver transplantation (LDLT) after successful consecutive downstaging therapies. A 63-year-old man with alcohol-related liver cirrhosis and multiple HCC developed spontaneous rupture and hemoperitoneum. He received 3 sessions of transcatheter hepatic arterial chemoembolization and target therapy with sorafenib. Computed tomography scans and magnetic resonance imaging after 11 months of treatment showed that the patient's HCCs fulfilled the Milan criteria and the University of California San Francisco criteria prior to LDLT. The perioperative course was rather smooth. After discharge, interval follow-up computed tomography studies of chest and liver and a whole-body bone scan showed no tumor recurrence or metastasis up to 20 months post-operation. Successful downstaging therapies of ruptured HCC to fulfill Milan criteria to receive liver transplantation is advisable in highly selected patients.

Diagnostic Analysis of Computed Tomography Patterns in Patients With Invasive Pulmonary Aspergillosis After Solid-Organ Transplantation.

The aim of this study was to assess initial and follow-up computed tomography findings of invasive pulmonary aspergillosis in solid-organ transplant recipients and to examine the most common computed tomography patterns during hospitalization. From January 2011 to September 2016, the total number of solid-organ transplant patients at our institution was 784. These patients consisted of 550 kidney, 164 liver, and 67 heart transplant recipients. Of these, 15 patients had a proven diagnosis of invasive pulmonary aspergillosis according to clinical and radiologic features with culture evidence of aspergillosis from bronchoalveolar lavage or lung biopsy. Computed tomography examinations were performed at initial diagnosis and at follow-up for evaluation of treatment. Computed tomography patterns were retrospectively evaluated by 2 experienced radiologists. Configurations and types of the largest lesions in each of the 15 patients were evaluated, and changes to lesions during treatment were recorded. Invasive pulmonary aspergillosis patterns were categorized into 6 main groups: ground-glass opacity, nodules, irregular nodules, patchy consolidation, cavity, and tree-in-bud patterns. The most common patterns were ground-glass opacity and irregular nodules, which were observed in 12 of 15 patients (80%), followed by regular nodules (73%), patchy consolidation and cavity (26%), and tree-in-bud pattern (20%). Long-term follow-up computed tomography studies showed that the regular nodules, tree-in-bud patterns, and groundglass opacity areas gradually reduced by 50% in 4 weeks. However, patchy consolidations and irregular nodules showed less regression than the other lesions over the 4-week period. Irregular nodules and ground-glass opacity were the most common computed tomography patterns in our solid-organ transplant recipients. Computed tomography patterns without irregular nodules and patchy consolidations may be associated with better prognosis due to their relatively rapid healing.

Transplantation After Successful Downstaging by Multimodal Treatments of American Joint Committee on Cancer Stage IIIB Hepatocellular Carcinoma With Portal Vein Thrombi: A Case Report

The effective treatment for hepatocellular carcinoma (HCC) with American Joint Committee on Cancer stage IIIB remains controversial and challenging because of the high recurrence rate after resection and low survival rate. The median survival of those with macroscopic portal vein tumor thrombus (PVTT) is short. We reported such a case which received liver transplantation (LT) after successful consecutive downstaging therapies. A 40-year-old man with alcohol related liver cirrhosis and repeated esophageal varices bleeding had HCC with tumor thrombi in right main portal vein and the second portal branch of segment VI (stage IIIB). The received percutaneous alcohol injection, radiofrequency ablation, 8 sessions of transcatheter hepatic arterial chemoembolization, radiotherapy, and target therapy with sorafenib. Computed tomography (CT) scan and magnetic resonance imaging after treatments showed no viable fragments in the tumor and revealed both the right main portal vein and V1 branch were patent. One month later, the patient received a deceased LT. The perioperative course was rather smooth. After discharge, the interval follow-up CT studies of the chest and liver and whole body bone scan showed no tumor recurrence or metastasis up to 20 months postoperation.

Ultrasound for Diagnosis of Appendicitis in a Community Hospital Emergency Department has a High Rate of Nondiagnostic Studies

BackgroundRadiation concerns are changing the way emergency physicians evaluate patients. This is especially prevalent in pediatrics, and exemplified by abdominal pain management. Large academic center-based studies suggest appendix ultrasound (U/S) is sensitive and specific for appendicitis, with low nondiagnostic rates. ObjectivesWe sought to determine the diagnostic rate of appendix U/S and incidence of follow-up computed tomography (CT) imaging for pediatric patients at a community hospital. MethodsDesign: Retrospective cohort. Setting: Emergency department with 85,000 annual visits. Population: Patients younger than 21 years old that had an appendix U/S over a 12-month period. U/S were performed by technicians and interpreted by radiologists. Investigators classified readings as “diagnostic” (“positive” and “negative”) or “non-diagnostic” (“borderline” and “appendix not visualized”) and identified follow-up CT studies and interpretations. ResultsThere were 441 pediatric appendix U/S performed; 26% were diagnostic (14% positive for appendicitis, 12% negative) and 74% nondiagnostic (5% borderline, 69% appendix not visualized). Follow-up CT scans were obtained in 19% of all patients, including 8% with positive U/S, 4% negative, 32% borderline, and 22% not visualized. Follow-up CT was nearly four times more likely in the nondiagnostic group than the diagnostic group (23% vs. 6%, p < 0.0001). ConclusionThe utility of U/S to diagnose appendicitis at a community hospital is limited by a high rate of nondiagnostic studies. Some patients with diagnostic U/S even had follow-up CT imaging. To minimize radiation exposure in children, improvements should be made in the performance and acceptance of U/S as the primary modality of abdominal pain imaging at community hospitals.

Organ Atrophy Induced by Sorafenib and Sunitinib – Quantitative Computed Tomography (CT) Evaluation of the Pancreas, Thyroid Gland and Spleen

SummaryBackgroundTo evaluate organ atrophy induced by sorafenib and sunitinib, we retrospectively reviewed the CT scans of renal cell carcinoma (RCC) patients receiving molecular targeted therapy (MTT) using sorafenib or sunitinib, and performed volumetric analysis of the pancreas, thyroid gland, and spleen.Material/MethodsThirteen RCC patients receiving MTT were assigned as the evaluation cases (MTT group), while thirteen additional RCC patients not receiving MTT were retrieved as the Control group. We evaluated the baseline and follow-up CT studies. The volume of the three organs estimated by CT volumetry was compared between the baseline and follow-up CTs. The atrophic ratio of the organ volume in the follow-up CT to that in the baseline CT was calculated, and compared between the MTT and Control groups.ResultsAll measured organs in the MTT group showed statistically significant volume loss, while no significant change was observed in the Control group. Mean atrophic ratio in the MTT group was 0.74, 0.58, and 0.82 for the pancreas, thyroid and spleen, respectively. The differences in atrophic ratios between both groups were all statistically significant (P<0.05).ConclusionsSingle-agent sorafenib or sunitinib therapy induced statistically significant atrophy in the pancreas, thyroid, and spleen.

CT and microbiologic follow-up in primary multidrug-resistant pulmonary tuberculosis.

Little attention has been paid to the initial and follow-up computed tomography (CT) features in primary multi-drug resistant tuberculosis (pMDR-TB) setting. To describe serial CT findings and clinical course of pMDR-TB with antibiotic treatment. For the last 10 years, 340 MDR-TB patients were managed in a tertiary referral hospital. Among them, we included 44 (27 men, 17 women; mean age, 40 years; age range, 20-81 years) pMDR-TB patients; 37 treated with chemotherapy only and seven treated with medical therapy plus surgery. CT findings were evaluated regarding tree-in-bud sign, acinar nodule, peribronchial, segmental or lobar consolidation and cavity, and their extent. Sputum negative conversion rates and serial CT scores were assessed. To compare changes in disease extent between initial and follow-up CT studies, paired t-test was performed. Two most frequent patterns of lung abnormality were tree-in-bud sign (37 of 44, 84.1%) and acinar nodule (41 of 44, 93.2%). Among 37 patients treated with chemotherapy only, 36 showed negative sputum conversion within 3 months after second-line drug commencement, maintained for >12 months. The other seven undergoing surgery during medical treatment showed excellent outcome with negative conversion achieved within one month after surgery and maintained for >12 months. CT scores showed significant decrease on serial CT studies (P < 0.001) in all. In pMDR-TB, two most frequent abnormal CT patterns are tree-in-bud sign and acinar nodule. In 98% of patients, negative sputum conversion is achieved, and CT score also shows decrease in extent after TB chemotherapy.

Wire or Hook Traction for Reducing Zygomatic Fracture.

BackgroundVariable methods have been introduced for reduction of the zygomatic fractures. The Dingman elevator is used widely to reduce these fractures but is inappropriate in certain types of fractures which require atypical traction vectors. We introduce and examine an alternate method of reducing zygomatic fractures using wire and hook traction.MethodsA retrospective study was performed for all zygomatic fracture patients admitted between 2008 and 2014. Medially rotated fractures were reduced by using a wire looped through an intermaxillary screw secured on the medial side of the zygoma. Laterally rotated fractures were reduced using a hook introduced through an infrazygomatic skin incision.ResultsNo accidental bleeding or incomplete reduction was observed in any of the cases. Postoperative imaging demonstrated proper reduction immediately after the operation. Follow-up computed tomography study at 1 month after operation also demonstrated proper reduction and healthy union across the previous site of fracture.ConclusionThe hook and wire method allowed precise application of traction forces across zygomatic fractures. The fractured bone fragment could be pulled in the direction precisely opposite to the vector of impact at the time of trauma. Soft tissue damage due to dissection was minimized. In particular, this method was effective in reducing rotated bone fragments and can be an alternative option to using the zygoma elevator.

Computed tomography evaluation of aortic remodeling after endovascular treatment for complicated ulcer-like projection in patients with type B aortic intramural hematoma

The purpose was to investigate changes of the affected aorta after endovascular treatment for complicated ulcer-like projection (ULP), including aneurysmal change or rupture of ULP, or both, in patients with type B aortic intramural hematoma (IMH). The study evaluated 18 patients (nine men) undergoing thoracic endovascular aortic repair for progressive aneurysmal formation of ULP (n = 17), rupture of ULP (n = 5), or both. Patients were a median age of 72 years (range, 45-83 years). Regular follow-up computed tomography studies were performed after treatment (mean follow-up, 61.2 months). A workstation was used to calculate changes on computed tomography images in the size or volume of ULP, affected aorta, and IMH. The growth rate of the volume of the affected aorta and IMH was also calculated before and after treatment. We evaluated the data using the paired t-test. A stent graft was successfully deployed and ULPs disappeared in all patients. IMH disappeared in 16 or decreased in two after treatment. There were significant differences in the mean maximum aortic diameter (37.8 ± 5.2 vs 34.5 ± 5.2 mm; P = .0006), mean IMH volume (39.4 ± 12.1 vs 2.0 ± 6.0 mL; P < .0001), and total volume of the aorta with IMH (158.1 ± 40.2 vs 128.9 ± 28.0 mL; P < .0001) before and after treatment. Endovascular treatment is a useful treatment for complicated ULP in patients with IMH. Endovascular treatment also contributes to ideal remodeling of the affected aorta.

New CT criteria for nodal staging in non-small cell lung cancer

ObjectiveThe purpose of our study was to develop a simple noninvasive technique for nodal staging using routine preoperative computed tomography (CT). Materials and methodsThe institutional review board approved this retrospective study, and written informed consent to perform the initial and follow-up CT studies was obtained from all patients. Preoperative CT findings (n=218 patients with resectable non-small cell lung cancer) and pathological diagnoses after surgical resection were evaluated. Using CT images, lymph node section area, circumference, and lesion attenuation values (LAVs) were drawn freehand, and the short axis (SA) and long axis (LA) were measured using caliper software. Receiver operating characteristic (ROC) curves were then used to analyze the section area, circumference, and LAVs. ResultsBased on ROC curves, two cut-off values, lymph node section area >30 mm2 and circumference >25 mm, showed greater sensitivity for nodal staging than the conventional criterion of lymph node SA ≥10 mm or the LA, SA/LA ratio or LAVs. Using lymph node section area >30 mm2 for diagnosis, the sensitivity, specificity, and accuracy of nodal staging were 90.5%, 56.3%, and 58.3%, respectively. Using lymph node circumference >25 mm, the values were 76.2%, 70.4%, and 70.8%, respectively. ConclusionLymph node section area >30 mm2 and circumference >25 mm can serve as supportive criteria used by radiologists and surgeons to determine nodal staging. If these CT criteria are met, use of a more sensitive procedure such as positron emission tomography or mediastinoscopy is recommended. Concise abstractCT is used routinely during preoperative management of lung cancer. Based on ROC analyses, the cut-off values for surface area, circumference, the SA/LA ratio, and LAVs for diagnosis of lymph node metastasis were 30 mm2, 25 mm, 0.65, and 50 Hounsfield units, respectively. Our findings indicate that lymph node surface area >30 mm2 and circumference >25 mm are supportive criteria that can be used by radiologists and thoracic surgeons to determine nodal staging and surgical indications.

Complications of Celect, Günther Tulip, and Greenfield Inferior Vena Cava Filters on CT Follow-up: A Single-Institution Experience

PurposeTo evaluate and compare the rates of complications on follow-up computed tomography (CT) studies of patients with Celect, Günther Tulip, and Greenfield inferior vena cava (IVC) filters. Materials and MethodsRetrospective review of CT studies obtained 0–1,987 days after infrarenal placement of an IVC filter identified 255 Celect, 160 Tulip, and 50 Greenfield filters. Follow-up CT studies were independently evaluated by two observers for IVC perforation, contact with adjacent organs, and filter fracture. Multivariate analysis was performed to identify factors associated with higher rates of IVC perforation, including age, IVC diameter, sex, and history of malignancy. ResultsIVC perforation was observed in 126 of 255 Celect filters (49%) with a mean follow-up of 277 days, 69 of 160 Tulip filters (43%) with a mean follow-up of 437 days, and one of 50 Greenfield filters (2%) with a mean follow-up of 286 days. A significantly higher IVC perforation rate was observed in women (45.5%) compared with men (30.8%; P = .002) and in patients with a history of malignancy (43.7%) compared with patients with no history of malignancy (29.9%; P < .001). Filter fracture was rare, observed in two of 255 Celect filters (0.8%), one of 160 Tulip filters (0.6%), and none of 50 Greenfield filters. ConclusionsNo significant difference was observed in IVC perforation rate between Celect and Tulip filters. Greenfield filters had a significantly lower rate of IVC perforation than Celect and Tulip filters. Higher IVC perforation rates were observed in women and patients with a history of malignancy.

Use of CT to Evaluate Pleural Invasion in Non–Small Cell Lung Cancer: Measurement of the Ratio of the Interface between Tumor and Neighboring Structures to Maximum Tumor Diameter

To develop a simple noninvasive technique for evaluating pleural invasion by using routine preoperative computed tomography (CT). The institutional review board approved this retrospective study, and written informed consent was obtained for performing the initial and follow-up CT studies. Preoperative CT findings (169 patients with possible pleural invasion) and pathologic diagnoses after surgical resection were evaluated. The length of the interface between the primary tumor and neighboring structures (arch distance) and the maximum tumor diameter were measured on CT images, after which arch distance-to-maximum tumor diameter ratios were calculated. Receiver operating characteristic (ROC) curves were used to analyze the ratios. Median arch distance-to-maximum tumor diameter ratios for pleural invasion categories (pl1, pl2, pl3) assessed by using the Union Internationale Contre le Cancer TNM staging system were as follows: pl1, 0.206 (25th-75th percentile, 0-0.486); pl2, 0.638 (25th-75th percentile, 0.385-0.830); and pl3, 1.092 (25th-75th percentile, 1.045-1.214) (P < .001 between groups). On the basis of the ROC curves, the cut-off value for invasion was an arch distance-to-maximum tumor diameter ratio of 0.9. When the ratio was greater than 0.9, the sensitivity and specificity for thoracic invasion and area under the ROC curve were 89.7%, 96.0%, and 0.976, respectively, which represents an improvement over values obtained by using conventional criteria (radiologists A and B: 46.7% and 74.2% and 91.3% and 84.8%, respectively). When diagnosing T3 or T4 lung cancer based on arch distance-to-maximum tumor diameter ratios, a higher performance level was achieved than that with use of conventional criteria. Measurement of the ratios is a simple noninvasive technique for evaluating pleural invasion at CT.

Workflow-centred evaluation of an automatic lesion tracking software for chemotherapy monitoring by CT

In chemotherapy monitoring, an estimation of the change in tumour size is an important criterion for the assessment of treatment success. This requires a comparison between corresponding lesions in the baseline and follow-up computed tomography (CT) examinations. We evaluate the clinical benefits of an automatic lesion tracking tool that identifies the target lesions in the follow-up CT study and pre-computes the lesion volumes. Four radiologists performed volumetric follow-up examinations for 52 patients with and without lesion tracking. In total, 139 lung nodules, liver metastases and lymph nodes were given as target lesions. We measured reading time, inter-reader variability in lesion identification and volume measurements, and the amount of manual adjustments of the segmentation results. With lesion tracking, target lesion assessment time decreased by 38 % or 22 s per lesion. Relative volume difference between readers was reduced from 0.171 to 0.1. Segmentation quality was comparable with and without lesion tracking. Our automatic lesion tracking tool can make interpretation of follow-up CT examinations quicker and provide results that are less reader-dependent. Computed tomography is widely used to follow-up lesions in oncological patients. Novel software automatically identifies and measures target lesions in oncological follow-up examinations. This enables a reduction of target lesion assessment. The automated measurements are less reader-dependent.

Three-Section Expiratory CT: Insufficient for Trapped Air Assessment in Patients with Cystic Fibrosis?

To estimate the effect of the number of computed tomography (CT) sections on trapped air (TA) assessment in patients with cystic fibrosis (CF) by using an established scoring system and a new quantitative scoring system and to compare CT and pulmonary function test (PFT) estimates of TA in a cross-sectional and longitudinal study. In this institutional review board-approved pilot study, 20 subjects aged 6-20 years (12 female and eight male; median age, 12.6 years) contributed two expiratory CT studies (three-section baseline CT, volumetric follow-up CT) and two PFT studies over 2 years after parental informed consent was obtained. From follow-up CT studies, seven sets were composed: Set 1 was volumetric. Sets 2, 3, 4, and 5, had spacing of 2.4, 4.8, 9.6, and 20.4 mm, respectively, between sections. Sets 6 and 7 contained five and three sections, respectively. Longitudinal follow-up was performed with three sections. All images were deidentified and randomized, and TA was scored with the Brody II system and a new quantitative system. Statistical analysis included the Wilcoxon signed rank test, calculation of Spearman and intraclass correlation coefficients, and use of three-section and linear mixed models. For the Brody II system, the intraclass correlation coefficient for set 1 versus those for sets 2 through 7 was 0.75 versus 0.87; however, mean scores from sets 6 and 7 were significantly lower than the mean score from set 1 (P = .01 and P < .001, respectively). For the quantitative system, the number of sections did not affect TA assessment (intraclass correlation coefficient range, 0.82-0.88; P > .13 for all). CT and PFT estimates were not correlated (r(s) = 20.19 to 0.09, P = .43-.93). No change in TA over time was found for CT or PFT (P > .16 for all). The number of sections affected Brody II estimates, suggesting that three-section protocols lead to underestimation of TA assessment in patients with CF when using the Brody II system; CT and PFT estimates of TA showed no correlation and no significant change over time.

A Case of Embolism due to a Floating Thrombus Migrating from the Left Atrial Appendage to the Ostium of the Celiac Artery

The present case was a 70 year-old dialysis patient who had experienced a prior cerebral infarction following atrial fibrillation. Her shunt suddenly occluded during dialysis, and she was transferred to our hospital. Transesophageal echocardiography revealed a floating, ball-like thrombus in the left atrial appendage (LAA). After thrombectomy in the shunt, acute thrombi were extracted. Despite anticoagulant therapy, the ball-like thrombus in the LAA did not dissipate and instead continued to enlarge. We planned surgical intervention involving a left atrial appendectomy without cardiopulmonary bypass through a left thoracotomy. However, her thrombus disappeared out of the LAA when she was intubated in the operating room. Her surgery was, therefore, stopped, and extubation was carried out. A computed tomography (CT) scan showed that the embolism had moved to the ostium of the celiac artery. Incidentally, this celiac artery had already been obstructed, and her inferior mesenteric artery had been the main supply of blood flow to the intestine, explaining why she had not developed intestinal ischemia. We continued anticoagulant therapy with warfarin. Follow-up CT studies were conducted at the outpatient clinic. However, the patient died due to a wide cerebral infarction before the 6-month checkup.

Characterization of Contrast Enhancement in the Ablation Zone Immediately after Radiofrequency Ablation of Renal Tumors

To characterize the degree of contrast enhancement within the ablation zone immediately after radiofrequency (RF) ablation of renal tumors. Patients with renal tumors treated with percutaneous RF ablation at one institution between January 2004 and October 2007 were retrospectively reviewed. For each tumor, computed tomography (CT) density measurements were made at four phases (noncontrast, arterial phase, parenchymal phase, and excretory phase) in each of four CT examinations (before ablation, day 0, 1 month, and 6 months). A total of 36 renal tumors in 34 patients were treated with CT-guided RF ablation in 35 sessions. Before RF ablation, all tumors exhibited enhancement after intravenous administration of contrast material. The peak density was reached during the parenchymal phase, with a partial washout of contrast agent in the excretory phase. On CT images acquired immediately after RF ablation (day 0), 28 of the 36 ablated tumors (78%) exhibited clinically significant homogeneous enhancement (ie, density change >10 HU) within the ablation zone. However, contrast-enhanced CT studies performed at 1 and 6 months revealed no clinically significant enhancements in any of the 36 treated tumors (mean density changes of 4 HU at 1 month and 3 HU at 6 months). Contrast-enhanced CT studies revealed a mild, temporary homogenous contrast enhancement of the ablation zone immediately after RF ablation of renal tumors, which should not be mistaken for a residual, unablated tumor. This enhancement in the ablation zone eventually disappears in follow-up contrast-enhanced CT studies.