Consecutive Computed Tomography Research Articles

Evaluation of 126 Consecutive Stereotactic Procedures: Brain Biopsy, Diagnostic Yield, Accuracy, Non-Diagnostic Results, Complications and Follow-up.

A retrospective analysis of 126 consecutive computed tomography (CT)-guided, frame-based stereotactic procedures in 121 patients is presented to evaluate the diagnostic yield, accuracy, complications, management of non-diagnostic cases and followup. The medical records of the identified patients were investigated retrospectively. Age, sex, surgical procedures, histopathological diagnosis, diagnostic yield, accuracy, complications, management of non-diagnostic cases and follow-up were analyzed in 121 consecutive patients. Stereotactic procedures were performed by the author by using Leksell's stereotactic system, and stereotactic biopsies were conducted under local anesthesia except for those patients who were not able to tolerate this treatment. These patients had control CT scans two hours after the operation. Patient age ranged from 2 to 82 years (mean 48 years). Stereotactic biopsy was performed in 112 patients. Cyst and abscess aspiration, intracystic catheter replacement and tumor resection with stereotactic craniotomy were among the other procedures. The diagnostic yield was 93%, and the histological accuracy was 63% with no mortality. Craniotomy and hematoma evacuation were required in two cases. The patients were followed up from one month to 17 years. Frame-based stereotactic biopsy is a safe and efficacious method with acceptable complications. Experience is important, but not sufficient for preventing complications and performing procedures accurately. Necrosis and gliosis are the most common non-diagnostic findings. Empirical treatment with presumptive diagnoses based on clinical and radiological findings and close clinical follow-up may not affect patients adversely. The follow-up of patients through examination and imaging is important to allow the revision of treatment when necessary.

CT-based morphometric analysis of C1 laminar dimensions: C1 translaminar screw fixation is a feasible technique for salvage of atlantoaxial fusions.

Background:Translaminar screw fixation has become an alternative in the fixation of the axial and subaxial cervical spine. We report utilization of this approach in the atlas as a salvage technique for atlantoaxial stabilization when C1 lateral mass screws are precluded. To assess the feasibility of translaminar fixation at the atlas, we have characterized the dimensions of the C1 lamina in the general adult population using computed tomography (CT)-based morphometry.Methods:A 46-year-old male with symptomatic atlantoaxial instability secondary to os odontoideum underwent bilateral C1 and C2 translaminar screw/rod fixation as C1 lateral mass fixation was precluded by an anomalous vertebral artery. The follow-up evaluation 2½ years postoperatively revealed an asymptomatic patient without recurrent neck/shoulder pain or clinical signs of instability. To better assess the feasibility of utilizing this approach in the general population, we retrospectively analyzed 502 consecutive cervical CT scans performed over a 3-month period in patients aged over 18 years at a single institution. Measurements of C1 bicortical diameter, bilateral laminar length, height, and angulation were performed. Laminar and screw dimensions were compared to assess instrumentation feasibility.Results:Review of CT imaging found that 75.9% of C1 lamina had a sufficient bicortical diameter, and 63.7% of C1 lamina had sufficient height to accept bilateral translaminar screw placement.Conclusions:CT-based measurement of atlas morphology in the general population revealed that a majority of C1 lamina had sufficient dimensions to accept translaminar screw placement. Although these screws appear to be a feasible alternative when lateral mass screws are precluded, further research is required to determine if they provide comparable fixation strength versus traditional instrumentation methods.

Three-dimensional Computed Tomographic Reconstruction of the Carotid Artery: Identifying High Bifurcation

To investigate variability in the level of bifurcation relative to other anatomical landmarks on computed tomography (CT) and to develop an objective and reproducible technique for identifying patients with a high carotid bifurcation who might therefore be at greater risk of operative complications. This was a retrospective cross-sectional, imaging study. A series of 86 nonselected consecutive CT carotid angiograms (172 arteries) were analysed. Using three-dimensional reconstructive software, the curved length (CL) of the internal carotid artery (ICA) and the straight-line distance (SLD) from the bifurcation to the base of skull was measured for 140 carotid arteries. The tortuosity index (TI) of each ICA was calculated by dividing CL by SLD. The relationship of the bifurcation to eight anatomical landmarks in the neck was assessed in order to identify a landmark that could act as a surrogate marker of high carotid bifurcation. The landmarks examined were the angle of mandible, greater horn of hyoid, body of hyoid, upper margin of thyroid cartilage, cervical vertebrae, mastoid process, sternoclavicular joint, and sternal notch. The median curved length of the ICA was 80.4mm (range 58.0-129.0mm). The median distance of bifurcation from the base of the skull was 72.7mm (range 58.1-98.1mm). There was excellent interobserver agreement in measuring SLD, with an intraclass correlation coefficient of 0.993 (p=.00). The median tortuosity index was 1.12 (range 1.01-1.64). Distance from the mastoid process had the greatest correlation with high bifurcation; Pearson's correlation coefficient of 0.894 (two-tailed p=.00). Bifurcations within 5cm of the mastoid process are likely to be in the highest quartile (82.9% sensitive, 80.1% specific). Measuring the distance of carotid bifurcation from the base of the skull (SLD), a measure previously not well defined, may be useful in predicting difficult neck dissection and endarterectomy. A distance from mastoid of ≤ 5cm may also alert the surgeon to potential difficulties.

Does the time between CT scan and chemotherapy increase the risk of acute adverse reactions to iodinated contrast media in cancer patients?

BackgroundCancer patients undergo routine computed-tomography (CT) scans and, therefore, iodinated contrast media (ICM) administration. It is not known whether a time-dependent correlation exists between chemotherapy administration, contrast enhanced CT and onset of acute ICM-related adverse reactions (ARs).MethodsAll consecutive contrast-enhanced CTs performed from 1 January 2010 to 31 December 2012 within 30 days of the last chemotherapy administration were retrospectively reviewed. Episodes of acute ICM-related ARs were reported to the pharmacovigilance officer. We analyzed time to CT evaluation calculated as the time elapsed from the date of the CT performed to the date of the last chemotherapy administration. Patients were classified into 4 groups based on the antineoplastic treatment: platinum-based, taxane-based, platinum plus taxane and other group.ResultsOut of 10,472 contrast-enhanced CTs performed, 3,945 carried out on 1,878 patients were considered for the study. Forty acute ICM-related ARs (1.01%; 95% CI, 0.70-1.33) were reported. No differences were seen among immediate (within 10 days of the last chemotherapy administration), early (11–20 days) and delayed (21–30 days) CTs. Median time to CT in patients who experienced an acute ICM-related AR by treatment group was not statistically different: 20 days (range 6–30), 17 days (range 5–22), 13 days (range 8–17), 13 days (range (2–29) for the platinum, taxane, platinum plus taxane and other group, respectively (P =0.251).ConclusionsOur results did not reveal any correlation between time to CT and risk of acute ICM-related ARs in cancer patients.

Effect of CT contrast on volumetric arc therapy planning (RapidArc and helical tomotherapy) for head and neck cancer

The objectives of the study were to evaluate the effect of intravenous contrast in the dosimetry of helical tomotherapy and RapidArc treatment for head and neck cancer and determine if it is acceptable during the computed tomography (CT) simulation to acquire only CT with contrast for treatment planning of head and neck cancer. Overall, 5 patients with head and neck cancer (4 men and 1 woman) treated on helical tomotherapy were analyzed retrospectively. For each patient, 2 consecutive CT scans were performed. The first CT set was scanned before the contrast injection and secondary study set was scanned 45 seconds after contrast. The 2 CTs were autoregistered using the same Digital Imaging and Communications in Medicine coordinates. Tomotherapy and RapidArc plans were generated on 1 CT data set and subsequently copied to the second CT set. Dose calculation was performed, and dose difference was analyzed to evaluate the influence of intravenous contrast media. The dose matrix used for comparison included mean, minimum and maximum doses of planning target volume (PTV), PTV dose coverage, and V45Gy, V30Gy, and V20Gy organ doses. Treatment planning on contrasted images generally showed a lower dose to both organs and target than plans on noncontrasted images. The doses for the points of interest placed in the organs and target rarely changed more than 2% in any patient. In conclusion, treatment planning using a contrasted image had insignificant effect on the dose to the organs and targets. In our opinion, only CT with contrast needs to be acquired during the CT simulation for head and neck cancer. Dose calculations performed on contrasted images can potentially underestimate the delivery dose slightly. However, the errors of planning on a contrasted image should not affect the result in clinically significant way.

Hepatocellular carcinoma: surveillance CT schedule after hepatectomy based on risk stratification.

To evaluate alternative schedules for surveillance computed tomography (CT) for patients who underwent hepatectomy for hepatocellular carcinoma ( HCC hepatocellular carcinoma ) and to demonstrate an appropriate schedule on the basis of stratification for risk of recurrence. CT and pathologic reports for consecutive patients with HCC hepatocellular carcinoma who underwent hepatectomy at one institution were evaluated with institutional review board approval. Univariate and multivariate analyses were performed to identify risk factors for recurrence. Patients were categorized into risk groups on the basis of classification and regression tree analysis. Average recurrence detection rates ( RDR recurrence detection rate s) between consecutive CT scans were calculated for existing and alternative surveillance schedules for each risk group, and the difference in RDR recurrence detection rate was determined by using the Student t test. A P value of less than .05 was considered to indicate a significant difference. Expected delay in diagnosis was also computed for the alternative surveillance schedules for each risk group. Two hundred sixty patients (216 men; mean age, 56.0 years ± 22.5) underwent 2705 CT studies. Independent risk factors for recurrence were microvascular invasion (P = .001), cirrhosis (P = .007), and tumor multiplicity (P = .001). Three risk groups (low, intermediate, and high) were identified. For low- and intermediate-risk groups, average RDR recurrence detection rate was not significantly different in the first 2 years after hepatectomy when the interval was extended from 3 months (3.3% and 4.6%, respectively) to 4 months (4.3% [expected delay, 16 days] and 6.1% [expected delay, 18 days], respectively) or for the subsequent 3 years when the interval was extended from 6 months (1.3% and 3.5%, respectively) to 12 months (2.5% [expected delay, 72 days] and 7.0% [expected delay, 103 days], respectively). This alternative schedule included five (35.7%) fewer CT scans than the 14 in the original schedule, and a reduction in radiation dose and cost during the 5-year follow-up period. Posthepatectomy surveillance CT schedules may be tailored and optimized according to stratification by risk of recurrence to reduce the frequency of CT scans without compromising surveillance benefits.

Revisiting the surface anatomy of the sciatic nerve in the gluteal region.

The surface anatomy of the sciatic nerve (SN) in the gluteal region is clinically important (e.g., intramuscular injection). Anatomy texts describe the nerve in relation to the posterior superior iliac spine (PSIS), ischial tuberosity (IT), and greater trochanter (GT) but descriptions are inconsistent. The surface anatomy of the SN was determined in relation to these bony landmarks using computed tomography (CT) scans in living adults. One hundred consecutive adult pelvic CT scans (36 females, mean age 76 years) were available for dual consensus analysis. A further 19 adults (9 females, mean age 74 years) underwent pelvic CT scans in both prone and supine positions. The surface projection of the SN along a line between the PSIS and IT and between the IT and GT was measured. The SN was identified in 95% of scans at a mean of 5.2 ± 1.0 cm from the PSIS and 11.4 ± 1.1 cm from the IT. The SN was a mean of 5.8 ± 0.8 cm from the IT and 6.2 ± 1.0 cm from the GT. There were no significant differences in mean positions of the nerve between sides and sexes. A small but clinically irrelevant difference in the surface marking of the SN was found between supine and prone positions with respect to the GT and IT but not in relation to the PSIS and IT. In living adults, the SN lies approximately one-third of the way along a line between the PSIS and IT and half way between the GT and IT.

Comparison of three software systems for semi-automatic volumetry of pulmonary nodules on baseline and follow-up CT examinations

Early diagnosis of lung cancer in a treatable stage is the main purpose of lung cancer screening by computed tomography (CT). Accurate three-dimensional size and growth measurements are essential to assess the risk of malignancy. Nodule volumes can be calculated by using semi-automated volumetric software. Systematic differences in volume measurements between packages could influence nodule categorization and management decisions. To compare volumetric measurements of solid pulmonary nodules on baseline and follow-up CT scans as well as the volume doubling time (VDT) for three software packages. From a Lung Cancer Screening study (NELSON), 50 participants were randomly selected from the baseline round. The study population comprised participants with at least one pulmonary nodule at the baseline and consecutive CT examination. The volume of each nodule was determined for both time points using three semi-automated software packages (P1, P2, and P3). Manual modification was performed when automated assessment was visually inaccurate. VDT was calculated to evaluate nodule growth. Volume, VDT, and nodule management were compared for the three software packages, using P1 as the reference standard. In 25 participants, 147 nodules were present on both examinations (volume: 12.0-436.6 mm(3)). Initial segmentation at baseline was evaluated to be satisfactory in 93.9% of nodules for P1, 84.4 % for P2, and 88.4% for P3. Significant difference was found in measured volume between P1 and the other two packages (P < 0.001). P2 overestimated the volume by 38 ± 24%, and P3 by 50 ± 22%. At baseline, there was consensus on nodule size categorization in 80% for P1&P2 and 74% for P1&P3. At follow-up, consensus on VDT categorization was present in 47% for P1&P2 and 44% for P1&P3. Software packages for lung nodule evaluation yield significant differences in volumetric measurements and VDT. This variation affects the classification of lung nodules, especially in follow-up examinations.

Appropriateness of selection criteria for CT examinations performed at an emergency department.

In the diagnosis of traumatic and nontraumatic emergencies, computed tomography (CT) is the most frequently performed procedure. The aims of this study were to find out whether CT report results can be used as a reliable tool for the diagnosis and management of patients at an emergency department and to evaluate the appropriateness of the selection criteria for CT examinations. For this reason, we analysed the emergency CT procedures according to the diagnostic hypothesis written on CT request forms, the results of the CT reports and the final diagnosis of the patients. One thousand consecutive CT procedures in the emergency department of a research hospital were retrospectively analysed. When the CT reports and the final diagnosis were evaluated, the sensitivity and specifity of the CT were found to be 0.81 and 0.85. According to the analysis of the CT reports, 55.8% of all the patients were reported to be normal. When the patient files were examined for the final diagnosis of the patients, 55.7% of the patients did not receive a final diagnosis related to the diagnostic hypothesis. The lowest correlation was found between the diagnostic hypothesis, the CT reports and the final diagnosis of the patients who underwent cranial CT procedure for trauma. The results of the CT reports can be used as a reliable parameter for the diagnosis and management of the patients at emergency departments. On the other hand, a high negative rate of CT reports was noted especially for the cranial CT examinations. CT selection criteria for the head trauma patients should be reconsidered. Since CT is a procedure involving ionising radiation, it is important that it is performed with the correct indications and the relevant clinical information is specified on the CT request forms.

Prevalence of idiopathic cuneate gyrus herniation based on emergency room CT examinations

Idiopathic brain herniation caused by a focal dural defect can be confused for a mass or post-traumatic herniation. The prevalence of idiopathic brain herniation has never been described. We sought to ascertain the prevalence of idiopathic cuneate gyrus herniation in a general emergency room (ER) population on computed tomography (CT) imaging. The purpose of this study is to elucidate cuneate gyrus herniation and differentiate it from other pathologic conditions such as mass or traumatic herniation and to provide its anatomical prevalence in an ER population. Consecutive emergency room CT scans of the brain were evaluated prospectively for cuneate gyrus herniation over a 1 year period by a neuroradiologist. Of 1,500 brain CT scans evaluated, 11 patients demonstrated idiopathic cuneus gyrus herniation. The prevalence was 0.73 %. CT manifestations are normal brain tissue herniating into the superior cerebellar cistern. Idiopathic brain herniation can be mistaken for a pathologic process. We found the prevalence of one such idiopathic brain herniation, involving the cuneus gyrus, to be exceedingly rare. CT imaging demonstrates normal brain tissue herniating beyond the dural boundary.

Ipsilateral arcuate foramen and high-riding vertebral artery: implication on C1–C2 instrumentation

Background contextSeveral methods for C1–C2 stabilization have been described in the literature. These include C1–C2 transarticular and C1 lateral mass screws. In patients with aberrant anatomy such as a high-riding vertebral artery (VA) or the presence of an arcuate foramen at C1, there exists a higher risk of VA injury. This may lead to excessive bleeding, stroke, and possibly death. There have been several studies determining the incidence of arcuate foramen and high-riding VA occurring individually in the general population, but none have determined their occurrence simultaneously. PurposeTo determine the prevalence of ponticulus posticus and high-riding VA occurring simultaneously in the general population. Study designRadiological study. MethodsOne hundred consecutive computed tomography (CT) scans of the cervical spine were reviewed. Scans that contained an arcuate foramen were identified, and it was indicated whether the foramen was right sided, left sided, or bilateral. In the same group, the thickness of the isthmus and the internal height of the lateral mass of C2 were measured. The VA was considered high riding if the isthmus thickness was less than 5 mm or the isthmus internal height was less than 2 mm. ResultsFourteen out of one hundred (14%) patients had a fully formed arcuate foramen. Of these, six were left sided, three were right sided, and five were bilateral. In addition, there were 24 (24%) patients with partially formed ponticulus posticus. Thirty-two (32%) patients were identified to have a high-riding VA. Of these, 13 were left sided, 9 were right sided, and 10 were bilateral. Five (5%) had an ipsilateral arcuate foramen and high-riding VA. ConclusionsThe arcuate foramen and high-riding VA are common anomalies that are often not recognized. Although ipsilateral high-riding VA and arcuate foramen rarely occur in the general population, proper identification of these anomalies on preoperative CT scan facilitates planning the safest technique for C1–C2 instrumentation.

Pure and Part-Solid Pulmonary Ground-Glass Nodules: Measurement Variability of Volume and Mass in Nodules with a Solid Portion Less than or Equal to 5 mm

To prospectively assess and compare the measurement variability of volume and mass for pure and part-solid ground-glass nodules (GGNs) with solid portions less than or equal to 5 mm by using a commercially available volumetric software program. This prospective study was approved by the institutional review board. Written informed consent was obtained. From November 2011 to June 2012, 73 patients (26 men and 47 women) with 94 GGNs (>5 mm and <20 mm; 72 pure and 22 part-solid GGNs) were prospectively enrolled and underwent two consecutive computed tomographic (CT) examinations. Both the volume and mass of GGNs were measured with volumetric software by two radiologists. Intraobserver, interobserver, and interscan variability were analyzed and compared by using the Bland-Altman method and coefficients of variation. The influence of the solid portion of GGNs and GGN size on interscan variability was investigated with multiple linear regression analysis and analysis of variance. Nodule segmentation was successful in 420 of 438 (95.9%) segmentations. As for volume measurement, interscan variability ranged from -17.3% to 18.5%, while intraobserver and interobserver variability ranged from -7.6% to 8.5% and from -11.7% to 18.1%, respectively. Interscan variability in mass measurement ranged from -17.7% to 18.6%, while intraobserver and interobserver variability ranged from -8.4% to 9.4% and from -17.5% to 11.8%, respectively. In the coefficient of variation comparison, there were no significant differences in volume and mass measurements for intraobserver, interscan, and interobserver variability. Measurement variability of volume and mass was not significantly influenced by the presence of a solid portion, solid portion size, or GGN size. Mass measurement of GGNs showed measurement variability from -17.7% to 18.6% and may be a useful method in the follow-up of GGNs with solid portions less than or equal to 5 mm.

Prevalence and imaging characteristics of detectable tonsilloliths on 482 pairs of consecutive CT and panoramic radiographs

BackgroundRecent studies suggest that tonsilloliths are clinically related to halitosis and tonsillar abscess. Based on our empirical knowledge, tonsilloliths are relatively commonly encountered in daily clinical practice. It has been reported that the detection rate of tonsilloliths was under 24% in previous reports, although experience suggests otherwise. The purpose of the study was to evaluate the prevalence and characteristics of tonsilloliths using computed tomography (CT). In addition, the possible causes of low detection rates on panoramic radiographs were evaluated based on comparisons between CT images and panoramic radiographs in order to elucidate the limitations of visualizing the area around the palatine tonsils on panoramic radiographs.Methods482 pairs of CT images and panoramic radiographs were retrospectively assessed with respect to the presence and characteristics of tonsilloliths. In addition, the causes in cases of disagreement between the two modalities were analyzed.ResultsThe detection rate of tonsilloliths was 46.1% using CT scans, unlike previous reports. The characteristics of tonsillolith were dot-like figures with about 300-500 Hounsfield units within the palatine tonsil under the soft palate. The most common length of tonsilloliths was about 3 or 4 mm. As the subjects aged, the detection rate increased gradually. A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001). However, the detection rate of tonsilloliths was only 7.3% on panoramic radiographs. A significant correlation was observed between the detection rate of tonsilloliths on panoramic radiographs and CT number (Spearman r = 0.429), size, (Spearman r = 0.318), and number of tonsilloliths (Spearman r = 0.333).ConclusionThe present results suggest that tonsilloliths are relatively more common than previously suggested. However, panoramic radiographs detect only a small percentage of palatine tonsilloliths. The low detection rates on panoramic radiographs might be related to the degree of calcification, size, and number of tonsilloliths.

Computed tomography for pulmonary embolism: assessment of a 1-year cohort and estimated cancer risk associated with diagnostic irradiation

The principal concern of any radiation exposure in computed tomography (CT) is the induction of stochastic risks of developing a radiation-induced cancer. The results given in this manuscript will allow to (re-)calculate yield of chest CT. To demonstrate a method to evaluate the lifetime attributable risk (LAR) of cancer incidence/mortality due to a single diagnostic investigation in a 1-year cohort of consecutive chest CT for suspected pulmonary embolism (PE). A 1-year cohort of consecutive chest CT for suspected PE using a standard scan protocol was analyzed retrospectively (691 patients, 352 men, 339 women). Normalized patient-specific estimations of the radiation doses received by individual organs were correlated with age- and sex-specific mean predicted cancer incidence and age- and sex-specific predicted cancer mortality based on the BEIR VII results. Additional correlation was provided for natural occurring risks. LAR of cancer incidence/mortality following one chest CT was calculated for cancer of the stomach, colon, liver, lung, breast, uterus, ovaries, bladder, thyroid, and for leukemia. LAR remains very low for all age and sex categories, being highest for cancer of the lungs and breasts in 20-year-old women (0.61% and 0.4%, respectively). Summation of all cancer sites analyzed raised the cumulative relative LAR up to 2.76% in 20-year-old women. Using the method presented in this work, LAR of cancer incidence and cancer mortality for a single chest CT for PE seems very low for all age groups and both sexes, but being highest for young patients. Hence the risk for radiation-induced organ cancers must be outweighed with the potential benefit or a treatment and the potential risks of a missed and therefore untreated PE.

Radiologic Measurement of Submandibular Gland Ptosis

Ptosis of the submandibular glands is a well-recognized yet poorly quantified element of the aging face and neck. The goal of this study is to describe and quantify the rate and extent of age-related submandibular gland ptosis. A novel grading system is proposed to quantify the degree of descent of the submandibular gland in relation to the inferior border of the mandible. Implications for facial rejuvenation surgery are discussed. Retrospective review. Consecutive computed tomography (CT) imaging studies performed at a university-affiliated hospital were selected for review. Using cross-referenced images in the coronal and axial planes, distance measurements were obtained from the bottom of the submandibular gland to the plane of the inferior border of the mandible. These data points were plotted against subject age for statistical analysis. The position of the submandibular gland was then categorized as grade I when distance below the mandible was < 20 mm, grade II for 20 to 25 mm, grade III for 25 to 30 mm, and grade IV for > 30 mm. Volumetric analysis was performed in a subset of subjects to assess for the possibility of age-related submandibular gland volume changes as a potential confounding factor in distance measurements. One hundred consecutive CT imaging studies were selected for review (50 men, 50 women). A statistically significant linear relationship was identified between subject age and ptosis of the submandibular gland (r = 0.52, p < 0.001), as measured by the distance from the bottom of the submandibular gland from the plane of the inferior border of the mandible. The average rate of descent was 0.17 mm per year. Overall, the position of the submandibular gland was categorized as grade I in 18% of patients, grade II in 27% of patients, grade III in 32% of patients, and grade IV in 23% of patients. No statistically significant gender differences were identified in any of the data points. Volumetric analysis did not demonstrate any age-related changes in submandibular gland volume, and as such, this was excluded as a potential confounding factor in distance measurements. A linear relationship exists between patient age and submandibular gland ptosis, as measured by the distance of the gland from the inferior border of the mandible. To our knowledge, this is the first quantification of the rate and extent of submandibular gland ptosis. A novel grading system for submandibular gland ptosis has been proposed.

Pure and Part-Solid Pulmonary Ground-Glass Nodules: Measurement Variability of Volume and Mass in Nodules with a Solid Portion Less than or Equal to 5 mm

To prospectively assess and compare the measurement variability of volume and mass for pure and part-solid ground-glass nodules (GGNs) with solid portions less than or equal to 5 mm by using a commercially available volumetric software program. This prospective study was approved by the institutional review board. Written informed consent was obtained. From November 2011 to June 2012, 73 patients (26 men and 47 women) with 94 GGNs (>5 mm and <20 mm; 72 pure and 22 part-solid GGNs) were prospectively enrolled and underwent two consecutive computed tomographic (CT) examinations. Both the volume and mass of GGNs were measured with volumetric software by two radiologists. Intraobserver, interobserver, and interscan variability were analyzed and compared by using the Bland-Altman method and coefficients of variation. The influence of the solid portion of GGNs and GGN size on interscan variability was investigated with multiple linear regression analysis and analysis of variance. Nodule segmentation was successful in 420 of 438 (95.9%) segmentations. As for volume measurement, interscan variability ranged from -17.3% to 18.5%, while intraobserver and interobserver variability ranged from -7.6% to 8.5% and from -11.7% to 18.1%, respectively. Interscan variability in mass measurement ranged from -17.7% to 18.6%, while intraobserver and interobserver variability ranged from -8.4% to 9.4% and from -17.5% to 11.8%, respectively. In the coefficient of variation comparison, there were no significant differences in volume and mass measurements for intraobserver, interscan, and interobserver variability. Measurement variability of volume and mass was not significantly influenced by the presence of a solid portion, solid portion size, or GGN size. Mass measurement of GGNs showed measurement variability from -17.7% to 18.6% and may be a useful method in the follow-up of GGNs with solid portions less than or equal to 5 mm.

Prevalence of radiologic superior canal dehiscence in normal ears and ears with chronic otitis media

Although labyrinth fistulae are caused mostly by cholesteatoma, they can occur in long-standing chronic otitis media (COM) without cholesteatoma. We aimed to compare the prevalence of radiologic SCD on computed tomography (CT) between normal ears and contralateral COM ears in patients with unilateral COM and to assess the prevalence of superior canal dehiscence (SCD) according to the age. Case series with comparison performed at a tertiary care academic referral center. We retrospectively reviewed consecutive temporal bone CT scans of 759 patients with unilateral COM between 2009 and 2011. The mean (± standard deviation) age was 48 years (±14 years). Images were independently evaluated by two otologists, and the bone overlying the superior canal was characterized as normal, suspicious, or definite SCD. The prevalence (3.4%) of definite SCD in COM ears was significantly higher than that (0.3%) in normal ears. The prevalence (6.6%) of suspicious or definite SCD in COM ears was also higher than that (1.2%) in normal ears. There was no correlation between the prevalence of SCD and age in either normal or COM ears. All of the normal ears with suspicious or definite SCD also showed contralateral suspicious or definite SCD (bilateral involvement). Our present findings suggest that the COM is related to the presence of SCD. The roof of the temporal bone may become thin by the failure of postnatal bone development and susceptible to chronic brain pulsation and pressure exerted by the temporal lobe in COM ears.

Left ventricular fat deposition on CT in patients without proven myocardial disease.

To analyze computed tomography (CT) characteristics of left ventricle (LV) fat deposition in patients without proven myocardial disease and to correlate these CT findings with electrocardiogram (ECG) and echocardiography data. We retrospectively searched our database of 14,470 consecutive coronary CT scans performed in the past 4years for LV fat deposition in patients without proven myocardial disease. In total, we identified 25 patients (0.2%; 10 males, 15 females; mean age 63years) involving 91 cardiac segments. Pattern and location of LV fat deposition on CT were analyzed and compared to ECG and echocardiographic data. LV fat deposition can be categorized into 3 patterns: fat deposits in an apical cap (pattern I, n=14), localized fat accumulation (pattern II, n=12), and diffuse linear accumulation (pattern III, n=6). Both patterns I and II were seen in 7 patients. The most common locations were apical segments (40%) and the mid-myocardial layer (70%). No patients had ECG findings positive for left-dominant arrhythmogenic dysplasia. Regional wall-motion abnormalities and decreased LV function (ejection fraction<50%) were only observed in 33% of pattern III cases. LV fat deposition on CT can be seen in patients without proven myocardial disease. LV fat depositions were most commonly seen in the mid-myocardial location and apical segments. Diffuse linear fat deposition in the LV may correlates with decreased regional and global function.

Template-Driven Computed Tomography Radiation Dose Reporting: Implementation of a Radiology Housestaff Quality Improvement Project

Radiation exposure from medical imaging has received increasing attention in recent years. Ongoing calls to report radiation doses received during radiology studies as a means of recording cumulative exposure and identifying rare over-exposures have culminated in the State of California passing a mandatory reporting requirement effective July 1, 2012. Herein we describe a radiology housestaff-led quality improvement project to track radiation dose reporting a full year prior to state reporting mandates using a template-driven reporting system and our results over the first 12 months of its implementation. Effective July 2011, all radiology trainees were instructed to use a standard computed tomography (CT) report template that included a CT dose measurement derived from dose information routinely displayed on our picture archiving and communication system. Consecutive reports from July 1, 2011, to June 30, 2012, of patients who underwent CT examinations at our institution were then retrospectively reviewed. Compliance of each study with the reporting requirement was assessed based on the presence or absence of a radiation dose statement within the finalized report. A total of 36,217 eligible consecutive CT reports were identified within the review period. Of these, 91.9% reported the radiation dose for the examination, greatly exceeding the initial goal of 80% compliance with the dose reporting requirement. Successful reporting of CT radiation doses resulted from template-driven reporting, readily accessible calculation tools to facilitate dose calculation, and minimization of reporting burden on the radiologist a full year prior to state regulatory mandates.

Improving Accuracy in Reporting CT Scans of Oncology Patients: Assessing the Effect of Education and Feedback Interventions on the Application of the Response Evaluation Criteria in Solid Tumors (RECIST) Criteria

In February 2010, our radiology department adopted the use of the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria for newly diagnosed oncology patients. Prior to staff used RECIST 1.1, we hypothesized that education and feedback interventions could help clarify differences between RECIST 1.0 and the newly adopted RECIST 1.1 guidelines and result in appropriate and accurate utilization of both reporting systems. This study evaluates the effect of education and feedback interventions on the accuracy of computed tomography (CT) reporting using RECIST criteria. Consecutive CT scan reports and images were retrospectively reviewed during three different periods to assess for compliance and adherence to RECIST guidelines. Data collected included interpreting faculty, resident, type, and total number of errors per report. Significance testing of differences between cohorts was performed using an unequal variance t-test. Group 1 (baseline): RECIST 1.0 used; prior to adoption of RECIST 1.1 criteria. Group 2 (post distributed educational materials): Following adoption of RECIST 1.1 criteria and distribution of educational materials. Group 3 (post audit and feedback): Following the audit and feedback intervention. The percentage of reports with errors decreased from 30% (baseline) to 28% (group 2) to 22% (group 3). Only the difference in error rate between the baseline and group 3 was significant (P = .03). The combination of distributed educational materials and audit and feedback interventions improved the quality of radiology reports requiring RECIST criteria by reducing the number of studies with errors.