Repeat Computed Tomography Examination Research Articles

Ability of three-dimensional 3-Tesla ultrashort echo time magnetic resonance imaging to display the morphological characteristics of pulmonary nodules: a sensitivity analysis.

Radiation-free lung cancer screening will reduce/eliminate radiation exposure in the diagnosis and follow-up of patients with lung cancer. This was a prospective study. The participants were recruited using convenience sampling. A total of 36 patients with pulmonary nodules [patients with single or multiple pulmonary nodules >4 and <30 mm on their pulmonary computed tomography (CT) scans] who were admitted to Fudan University Zhongshan Hospital's Xiamen branch were enrolled; they underwent a CT scan and a free-breathing ultrashort time-of-echo (UTE) sequence scan using a 3-Tesla (T) magnetic resonance imaging (MRI) scanner. The CT examinations were regarded as the reference standard. Patients had an interval time of <3 days between their CT and MRI examinations. Two reviewers with more than 10 years' experience in the diagnosis of pulmonary nodules identified the numbers and morphological features of the pulmonary nodules. Among the 36 patients, 46 nodules were detected on CT images, 45 of which were also detected on UTE images (a detection rate of 97.6%). The detection rate for lobulation using UTE-MRI was 96.9%; however, the difference compared with the rate for the CT images was not statistically significant (P>0.05). In terms of confounding lesions (confounding lesions indicate that the patient has malignant tumours, benign nodules or inoperable nodules), the UTE-MRI method had a higher detection rate than the CT method, and the difference was significant (P<0.05). The probability of malignant lesions was found to be higher in confounding lesions than in homogeneous lesions. In terms of pleural traction, the UTE-MRI method demonstrated a higher detection rate (120%) than the CT method, but the difference was not statistically significant (P>0.05). In terms of spiculation, the UTE-MRI method demonstrated a lower detection rate (81.8%) than the CT method, although the difference was not statistically significant (P>0.05). Overall, 3-T UTE-MRI imaging has a high detection rate for pulmonary nodules >4 mm and is similar to that of conventional CT imaging. The method can be used for radiation-free lung cancer screening and follow-up examinations to reduce/eliminate both repeat CT examinations and radiation damage.

Trend and Factors Associated with Repeat Computed Tomography Examinations in Tertiary Hospitals: Linked Health Administrative Data in Western Australia

IntroductionComputed tomography (CT) has become an essential part of clinical practice. However, repeat CT scans has raised a concern about unnecessary exposure to ionising radiation and waste of health care resource. While substantial effort is underway to reduce inappropriate use of diagnostic imaging tests including CT, little evidence of any change in repeat CT use and its associated factors. Objectives and ApproachThis study aimed to measure trend in repeat CT use and identify factors associated with repeat CT use in tertiary hospitals in Western Australia (WA). This study used WA linked administrative records from hospital morbidity, emergency department presentations, and picture archiving and communication system datasets to capture all tertiary hospitalisations and number of CT use during the admission from 2003 to 2015. Multivariate logistic regression was used to examine trend and determine characteristics associated with repeat CT, for admissions with and without major surgery during hospitalisation. ResultsAmong 303,439 admissions with CT scan 11.9% had repeat CT scan in the same anatomic areas. While the probability of repeat CT among admission with surgery remained unchanged over the study period, its counterpart significantly reduced about 4% per year. Regardless of surgical status, repeat CT scanning was significantly lower among females, Indigenous and older age groups but higher among people living in rural and remote areas. We found that admissions for circulatory conditions, injuries, cancer or multimorbidity had significantly higher probability of having repeat CT. Conclusion / ImplicationsThis study indicates that clinical factors such as cancer, injury and multimorbidity are factors contributing to repeat CT. A reduction of repeat CT over the study period among admissions without surgical procedure suggests a potential reduction of unnecessary CT scan, although further study is needed to fully capture whether this is an actual change in practice.

Radiation dose exposure in patients affected by lymphoma undergoing repeat CT examinations: how to manage the radiation dose variability.

To assess the variability of radiation dose exposure in patients affected by lymphoma undergoing repeat CT (computed tomography) examinations and to evaluate the influence of different scan parameters on the overall radiation dose. A series of 34 patients (12 men and 22 women with a median age of 34.4 years) with lymphoma, after the initial staging CT underwent repeat follow-up CT examinations. For each patient and each repeat examination, age, sex, use of AEC system (Automated Exposure Control, i.e. current modulation), scan length, kV value, number of acquired scans (i.e. number of phases), abdominal size diameter and dose length product (DLP) were recorded. The radiation dose of just one venous phase was singled out from the DLP of the entire examination. All scan data were retrieved by our PACS (Picture Archiving and Communication System) by means of a dose monitoring software. Among the variables we considered, no significant difference of radiation dose was observed among patients of different ages nor concerning tube voltage. On the contrary the dose delivered to the patients varied depending on sex, scan length and usage of AEC. No significant difference was observed depending on the behaviour of technologists, while radiologists' choices had indirectly an impact on the radiation dose due to the different number of scans requested by each of them. Our results demonstrate that patients affected by lymphoma who undergo repeat whole body CT scanning may receive unnecessary overexposure. We quantified and analyzed the most relevant variables in order to provide a useful tool to manage properly CT dose variability, estimating the amount of additional radiation dose for every single significant variable. Additional scans, incorrect scan length and incorrect usage of AEC system are the most relevant cause of patient radiation exposure.

Body composition indices and tissue loss in patients with resectable gastric adenocarcinoma

AbstractBackgroundBody composition analyses from computed tomography (CT) scans have been used to assess cachexia in cancer patients. We investigated body composition indices, tissue change and treatment outcome in patients with resectable gastric adenocarcinoma.MethodsA cohort analysis of all patients treated with curative intent for gastric adenocarcinoma in two Scandinavian university hospitals from 2008–2011 was performed (n=137). Body composition analyses were performed on CT images taken for routine diagnostics and staging. Both preoperative single scans and repeat CT examinations were analyzed.ResultsPerioperative chemotherapy was given to 58 (42.3%) patients. Forty patients (29.2%) suffered severe postoperative complications and 70 (51.1%) patients died within three years. There was a significant reduction in patients' lean tissue during neoadjuvant chemotherapy (p=0.001). There was no association between skeletal muscle tissue index and postoperative complications. Poorer survival was observed in patients with preoperative skeletal muscle tissue index within the lowermost quartile, independent of tumor characteristics and neoadjuvant treatment (HR=1.91, 95% CI 1.11–3.28, p=0.019).ConclusionsPatients lost lean tissue during neoadjuvant treatment for gastric adenocarcinoma. Low preoperative skeletal muscle index was not associated with postoperative complications, but strongly associated with poorer survival.

Quality control in Computed Tomography

Computed Tomography (CT) is considered as one of the most important imaging techniques of modern times. The introduction of multi-detector CT (MDCT) with sub second acquisition and CT fluoroscopy have further advanced CT applications by enabling interventional radiological (IR) procedures which were traditionally performed using C-arm machines. CT use is extended to CT fluoroscopy, angiography, cardiac CT, screening, multi-phase dynamic CT, urography and other applications. Due to the shorter MDCT scanning times, increasing number of patients receive repeat CT examinations especially in the oncology and emergency departments of hospitals. The development of hybrid systems such as PET/CT, SPECT/CT, CT simulators in radiotherapy and its incorporation in CT planning and dose delivery systems, progressed CT from the domain of diagnostic radiology to other specialities. Although vendors have invested time and exhausting efforts in development of radiation dose optimization techniques, contribution of CT to patient radiation dose continues to increase. Furthermore, growing number of adverse events related to excessive CT radiation exposure, as well as its relation to elevated risk of radiation induced cancer are reported in the media. All these clearly point to the critical need for ongoing quality control (QC) and cautious relation of radiation dose and image quality. An extensive review of the latest routine QC tests will be presented, based on the most recent publications, starting from more simple tests that can be easily performed by a radiation technologist to the more complex ones that must be executed and analysed by a medical physicist.

Acute pancreatitis: a comparison of intervention rates precipitated by early vs guideline CT scan timing

To assess whether computed tomography (CT) examination earlier in acute pancreatitis (AP) precipitates any surgical or radiological intervention. A single-centre retrospective cohort study comparing intervention rates in AP precipitated by early (<6 day of admission, n=100) and UK guideline (≥6 day of admission, n=103) CT examinations. No intervention was precipitated by performing CT before the sixth day of admission in AP. A statistically significant larger number of interventions were precipitated when CT was performed on the sixth day or later (p<0.05). Of note, this study was conducted using day of admission, rather than day of symptom onset. Six patients underwent repeat CT examination in the same admission after an early CT examination. Performing CT before the sixth day of admission does not lead to earlier intervention. Such early examinations waste resources and may offer false reassurance to clinicians.

Evaluation of Acute Abdominal Pain in the Emergency Setting Using Computed Tomography Without Oral Contrast in Patients With Body Mass Index Greater Than 25.

To evaluate the rate of delayed or missed diagnoses and need for additional computed tomography (CT) imaging in emergency department patients with abdominal pain who are imaged without oral contrast. The institutional review board approved this Health Insurance Portability and Accountability Act-compliant retrospective study; informed consent was waived. All consecutive adult patients with body mass index greater than 25 undergoing a CT abdomen/pelvis with intravenous contrast and without oral contrast with nontraumatic acute abdominal pain during a 16-month period at our academic tertiary care center were included. Medical records were reviewed, imaging findings on admission CT, use of repeat CT examinations within 4 weeks of the original examination, and clinical outcomes were recorded. In patients undergoing repeat imaging, an investigator determined whether repeat imaging was influenced by the lack of oral contrast on the original examination. As the most common cause of bowel-related positive CT scans, an analysis of acute appendicitis was performed. Of the 1992 patients included in this study, 4 patients (0.2%) underwent repeat CT studies directly related to the absence of oral contrast on the original examination. Of the 1992 CT scans, 1193(59.8%) were interpreted as negative, none of which required surgery or direct intervention. In patients with acute appendicitis, there was a sensitivity of CT in this patient population of 100% with a specificity of 99.5%. In patients with body mass index greater than 25 presenting to the ED with acute abdominal pain, CT examinations can be acquired without oral contrast without compromising the clinical efficacy of CT.

Variation in quantitative CT air trapping in heavy smokers on repeat CT examinations

ObjectivesTo determine the variation in quantitative computed tomography (CT) measures of air trapping in low-dose chest CTs of heavy smokers.MethodsWe analysed 45 subjects from a lung cancer screening trial, examined by CT twice within 3 months. Inspiratory and expiratory low-dose CT was obtained using breath hold instructions. CT air trapping was defined as the percentage of voxels in expiratory CT with an attenuation below −856 HU (EXP−856) and the expiratory to inspiratory ratio of mean lung density (E/I-ratioMLD). Variation was determined using limits of agreement, defined as 1.96 times the standard deviation of the mean difference. The effect of both lung volume correction and breath hold reproducibility was determined.ResultsThe limits of agreement for uncorrected CT air trapping measurements were −15.0 to 11.7 % (EXP−856) and −9.8 to 8.0 % (E/I-ratioMLD). Good breath hold reproducibility significantly narrowed the limits for EXP−856 (−10.7 to 7.5 %, P = 0.002), but not for E/I-ratioMLD (−9.2 to 7.9 %, P = 0.75). Statistical lung volume correction did not improve the limits for EXP−856 (−12.5 to 8.8 %, P = 0.12) and E/I-ratioMLD (−7.5 to 5.8 %, P = 0.17).ConclusionsQuantitative air trapping measures on low-dose CT of heavy smokers show considerable variation on repeat CT examinations, regardless of lung volume correction or reproducible breath holds.Key Points• Computed tomography quantitatively measures small airways disease in heavy smokers.• Measurements of air trapping vary considerably on repeat CT examinations.• Variation remains substantial even with reproducible breath holds and lung volume correction.

Interstitial lung diseases in a lung cancer screening trial

We assessed the prevalence of interstitial lung disease (ILD) in a cohort of smokers included in a lung cancer screening trial. Two observers independently reviewed, for the presence of findings consistent with ILD, the computed tomography (CT) examinations of 692 heavy smokers recruited by the Multicentric Italian Lung Detection (MILD) trial. Four CT patterns were considered: usual interstitial pneumonia (UIP), other chronic interstitial pneumonia (OCIP), respiratory bronchiolitis (RB) and indeterminate. Subsequently, the evolution of ILD in those subjects who had undergone a repeat CT examination after 3 yrs was assessed. The UIP pattern and the OCIP pattern were identified in two (0.3%) out of 692 and 26 (3.8%) out of 692 patients, respectively; 109 (15.7%) out of 692 patients showed CT abnormalities consistent with RB, while an indeterminate CT pattern was reported in 21 out of 692 (3%) patients. Age, male sex and current smoking status were factors associated with the presence of OCIP and UIP (combined) pattern, although the relationship did not attain statistical significance. A progression of the disease was observed in three (25%) out of 12 subjects with OCIP who underwent repeat CT after 3 yrs. Thin-section CT features of ILD, probably representing smoking-related ILD, are not uncommon in a lung cancer screening population and should not be overlooked.

Evaluation of Bowel and Mesenteric Blunt Trauma with Multidetector CT

Bowel and mesenteric injuries are detected in 5% of blunt abdominal trauma patients at laparotomy. Computed tomography (CT) has been shown to be accurate for the diagnosis of bowel and mesenteric injuries and is the diagnostic test of choice in the evaluation of blunt abdominal trauma in hemodynamically stable patients. Specific CT findings of bowel and mesenteric injuries include bowel wall defect, intraperitoneal and mesenteric air, intraperitoneal extraluminal contrast material, extravasation of contrast material from mesenteric vessels, and evidence of bowel infarct. Specific signs of mesenteric injury are vascular beading and abrupt termination of mesenteric vessels. Less specific signs of bowel and mesenteric injuries include focal bowel wall thickening, mesenteric fat stranding with focal fluid and hematoma, and intraperitoneal or retroperitoneal fluid. When only nonspecific signs of bowel and mesenteric injuries are seen on CT images, correlation of CT features with clinical findings is necessary. A repeat CT examination after 6-8 hours if the patient's condition is stable may help determine the significance of these nonspecific findings.

Mastoid effusion associated with dural sinus thrombosis

Sir, We read with great interest the excellent review by Agid and Farb [1] describing the association between the development of mastoid air cell effusions with dural sinus thrombosis. The authors pointed out that it was likely that a mastoid effusion was a secondary rather than a primary event due primarily to occlusion of the emissary vein draining the mastoid sinus. We would like to add supportive evidence to their theory by means of an unusual sequence of imaging events that we recently encountered at our institution. A 23-year-old woman with a history of migraine underwent computed tomography (CT) of the head to exclude a space-occupying lesion as a cause of her headaches. Her CT scan was normal. In particular, there was no evidence at this stage of a dural sinus thrombosis. Of note, her mastoid air cells showed no abnormality (Fig. 1). Lumbar puncture and other investigations were all normal at this stage. She had no other medical problems, but was taking the combined oral contraceptive pill. The patient was discharged with a diagnosis of migraine, but re-presented with a recurrent headache and vomiting 10 days later. A repeat CT examination at this stage demonstrated clear evidence of a dural sinus thrombosis as well as a newly developed ipsilateral mastoid effusion (Fig. 2). Magnetic resonance venography (MRV) further confirmed thrombosis of the lateral and superior saggital sinus (Fig. 3). The patient was anticoagulated andwas discharged 10 days following admission. The aetiology of the dural sinus thrombosis in this case was felt to be related to a combination of the oral contraceptive pill and dehydration from excessive vomiting. It is likely that the development of the lateral sinus component of the thrombus occluded the emissary vein from the mastoid sinus, resulting in the effusion. The presence of an initial normal CT indicated either the lack of a dural thrombus at this stage or possibly the presence of a small or early undetectable dural thrombus. In either case, the

Management of acute lumbar disk herniation initially presenting as mechanical low back pain

Objective: To describe the clinical management with spinal manipulation of a male patient with risk factors for lumbar disk herniation initially suffering from what appeared to be mechanical low back pain that evolved into radiculopathy; also to review issues pertinent to chiropractic/manipulative management of disk herniation. Clinical Features: The patient initially suffered from unilateral low back pain and nonradicular/nonlancinating referral to the ipsilateral lower extremity. Intervention and Outcome: Disk herniation-in-evolution was included in the differential diagnosis, which was discussed with the patient, who then gave verbal informed consent for manipulative management. A day or so after the initial manipulation the presentation evolved to include S1 radiculopathy. Computed tomography, just after onset of radiculopathy, confirmed the clinical diagnosis of lumbosacral disk herniation. The patient continued with manipulative management and repeat computed tomography examination after clinical resolution about 2 months later revealed reduction in size of the apparently clinically significant herniation. Conclusion: Risk factors for the development of disk herniation should be considered when assessing patients suffering from what appears to be mechanical low back pain. The role played by manipulation in the development of disk herniation in this case was believed to be circumstantial rather than causal. Manipulation was used in the treatment of this patient over a period of approximately 2 months; after this time, clinical and partial computed tomography imaging resolution was evident. Ongoing clinical (neurologic) evaluation of patients with manifest or suspected disk herniation is an important aspect of management. Good-quality trials of manipulation for patients with disk herniation are imperative for the chiropractic profession. (J Manipulative Physiol Ther 1999;22:235–44)

Is the standardized helmet technique adequate for irradiation of the brain and the cranial meninges?

Purpose : To evaluate whether the standardized helmet technique is adequate to reliably cover the clinical target volume (whole brain including cranial meninges) during treatment planning and treatment delivery. Methods and Materials : In 21 patients undergoing irradiation of the brain in acute lymphoblastic leukemia or primary cerebral lymphoma, the coverage of the clinical target volume was checked with a repeat computed tomography (CT) in the treatment position (head fixation with face mask). The accuracy of field alignment was quantitatively assessed with sequential verification films. For each patient, linear and rotational discrepancies were measured between the simulation and first check film, and between five consecutive verification films. Results : Coverage of clinical target volume. In 11 cases (52%), the CT examinations showed that parts of the subfrontal region and midcranial fossa were not included by the field assigned under simulation. Accuracy of field alignment. For the total group of patients, all deviations were normally distributed with mean values between –1.2 mm and 1.5 mm and standard deviations of 2.9 mm to 3.7 mm for linear discrepancies, and 0.3 degrees ± 3.2 degrees for rotational discrepancies. For all patients, deviations were similar for the transition from simulation to the treatment machine and for subsequent treatment delivery, with 50% and 95% of absolute differences being less than 2.0 mm and 6.5 mm, respectively. Maximum linear deviations were less than 9.5 mm. Conclusions : The currently used helmet technique is inadequate to cover the clinical target volume. Repeat CT examinations are a useful method to delineate the clinical target volume on an individual patient basis. In addition, statistical fluctuations of field displacements up to 1.0 cm have to be considered when prescribing safety margins for reliable coverage of the clinical target volume during treatment planning and delivery.