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PubMed1993

Fine needle aspiration cytology of submucosal nodules in patients with Zollinger-Ellison syndrome.

Submucosal nodules are often encountered during investigations of the upper gastrointestinal (GI) tract. This is particularly true in diseases resulting in chronic hypergastrinemia, such as Zollinger-Ellison syndrome (ZES), in which submucosal gastric and duodenal lesions can occur. Forceps biopsy of submucosal lesions often yields only normal mucosa; however, fine needle aspiration cytology (FNAC) has recently been described as having high diagnostic accuracy for submucosal tumors. Therefore, we prospectively studied the use of FNAC in 43 patients with ZES. Overall, 33% of patients with ZES had nodules. In patients with the sporadic form of ZES, submucosal nodules were found in 18%, whereas submucosal nodules were found in 80% of patients who had ZES in conjunction with multiple endocrine neoplasia type I (MEN-I). FNAC identified 11/12 (92%) of the neuroendocrine tumors, and identified another 8/9 as non-neuroendocrine. Jumbo forceps biopsy was performed on 18 nodules and diagnosed one neuroendocrine tumor. Subsequently, 11 of these nodules were found to possess neuroendocrine tumor; thus only 1/11 (9%) neuroendocrine tumors removed were accurately identified by jumbo forceps biopsy. Of the first 14 nodules, sufficient tissue was left after biopsy to permit snare polypectomy on 12 nodules. Four nodules were found to contain neuroendocrine tumor. Snare polypectomy resulted in a duodenal perforation that required surgery in one patient, and thus was not performed on the final seven nodules.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗

PubMed1996

Adrenocortical nodules in post-mortem series. Development, functional significance, and differentiation from adenomas.

In 498 consecutive autopsy cases, the adrenal glands were light microscopically and morphometrically studied. 265 (53.7%) patients showed single or multiples nodules, 25 (5.0%) adenomas. The diameter of nodules was between 0.3 to 8.0 mm and that of adenomas between 3.2 to 28.0 mm. Clinically, 265 (36.5%) patients revealed arterial hypertension. 283 (63.5%) were normotensive. For the diagnosis of adenomas, the architecture and the cell structure were more important than the size of the tumor. Normotensive patients showed more often (55.%) nodules than hypertensive patients (52.8%). Adenomas were more frequently found in hypertensive patients. There was no correlation between age, sex and nodules, but adenomas were more frequently found in females. Normotensive patients exhibited mainly one nodule, whereas multiple nodules were found in hypertensive patients. In patients with nodules arteriosclerosis with intima hyalinosis was present in 184 (56.3%) cases, in patients without nodules in 81 (47.4%) cases. Our study clearly demonstrates that no correlation exists between the occurrence of adrenocortical nodules and age or hypertension. The etiology of adrenal nodules should be considered together with the arteriopathy.

Adenoma↗

PubMed1997

[Detection of simulated lung nodules evaluated with various film/screen systems].

The imaging characteristics (contrast and noise) of x-ray film/screen combinations were examined for their suitability in the detection of faint nodules of lung cancer. Two hundred conventional chest radiographs of a human chest phantom were obtained with 5 mm or 10 mm spherically or hemispherically shaped simulated nodules placed on the posterior surface of an anthropomorphic chest phantom. Nodules were placed on several selected lung areas, and were overlain by the intercostal spaces, ribs or mediastinum. Five combinations of film/screen systems that differed in their contrast (characteristic curve) and noise were used to obtain the radiographs. The detectability of simulated nodules shown on the radiographs was evaluated based on the results obtained by an interpretive study by 6 observers utilizing receiver operating characteristic (ROC) analysis and calculating the average area under the ROC curve (Az). The system with standard contrast and improved noise reduction was favorable in detecting nodules of 5 mm in diameter. The system with latitude-type contrast was not suitable for the detection of nodules placed in the intercostal spaces. Systems with degraded noise or low contrast showed poor performance in detecting hemispheric nodules, since ill-defined nodules were overlain by the ribs. For the detection of nodules on the mediastinum or diaphragm, display of these regions with sufficient density and improved contrast appeared mandatory. The combination of a high contrast x-ray film, Iow noise x-ray film/screen combination, high voltage x-ray exposure, and the addition of a compensatory x-ray filter or screen appears suitable for improved recognition of a small, faint, lung nodules.

Humans↗

PubMed2003

Is the effect of fine-needle aspiration biopsy on the thyroid nodule volume important to evaluate the effectiveness of suppression therapy?

Fine-needle aspiration biopsy (FNAB) is recommended for the initial evaluation of thyroid nodule. If a benign cytology is obtained, suppression therapy with levothyroxine is the first choice in the management of nodular goiter with a follow-up of nodule size with ultrasonography, but the effects of FNAB have not been taken into consideration in this approach. We aimed at evaluating the effect of FNAB on thyroid volume and other ultrasonographic dimensions by measurement of these parameters before and immediately after the procedure, and in later periods, and to clarify the necessity of regarding the effects of FNAB on thyroid. Forty-six patients (34 females, 12 males; mean age: 36.3+/-10.7 yr) with solitary thyroid nodules were included in the study. The nodules were solid in ultrasonography, thyroid function tests were normal and results of FNAB were found as benign cytology. Thyroid hormone suppression therapy was not initiated. Ultrasonographic measurements were made before FNAB, repeated immediately after FNAB, and 1 month and 6 months later. There were no statistically significant changes in the mean thyroid nodule volume, nodule area and circumference of patients before, immediately after FNAB, 1 month and 6 months later. Size differences and individual variability at each time period were analyzed. These parameters changed by more than 10% in a great majority (69.5-78.2%) of patients, and more than 50% change was observed in 17.3-26.0% of patients. Changes in thyroid dimensions were bi-directional, both increment and decrement being noticed. It was thought that this is the reason why there was no significant change in mean nodule volume, area and circumference. Evaluating the difference in nodule volume according to ultrasonographic parameters obtained before FNAB may be misleading because of the individual change in these parameters with FNAB. It may be useful to evaluate the nodule size and volume closely after FNAB to make a true correspondence of these parameters in the long term.

Adult↗

PubMed2006

Integrated multislice CT and Tc-99m Sestamibi SPECT-CT evaluation of solitary pulmonary nodules.

PURPOSE: The purpose of this study was to evaluate efficacy of multislice computed tomography (MSCT) and single photon emission computed tomography (SPECT)-CT with Tc-99m Sestamibi in the assessment of solitary pulmonary nodules of uncertain significance. Scintigraphy was performed using a 'hybrid' g-camera that allows simultaneous acquisition of SPECT and CT images, with interesting results in diagnostic oncology. MATERIALS AND METHODS: Between September 2003 and August 2004, 23 patients with a solitary pulmonary nodule detected on CT underwent SPECT-CT using Tc-99m Sestamibi as a radiotracer. Nodules with positive scintigraphy were immediately subjected to biopsy or surgical resection. Nodules with negative scintigraphy were followed up after 3-4 months by MSCT with automatic segmentation software (Advanced Lung Analysis, ALA) and histological characterisation. RESULTS: Of the 23 nodules (size range 0.8-2 cm) discovered with MSCT, 11 showed intense uptake of Tc-99m Sestamibi. Ten lesions were true positive: seven adenocarcinomas, one squamous cell carcinoma, one large cell carcinoma and one metastasis. The only false positive was histologically classified as a large cell granuloma. Twelve lesions had negative scintigraphy: five fibrous lesions, three hamartomas, three granulomas and one adenocarcinoma (false negative). Benign nodules without tracer uptake underwent another CT scan 3-4 months later, which confirmed stability of the nodule size. Correlation of Sestamibi SPECT with histology showed sensitivity (Se) of 90.9 %, specificity (Sp) of 91.6 %, diagnostic accuracy of 91.3 %, positive predictive value (PPV) of 90.9% and negative predictive value (NPV) of 91.6 %. CONCLUSIONS: The integrated use of MSCT and Tc-99m Sestamibi SPECT-CT could be very useful in the management of solitary pulmonary nodules (SPNs). In particular, in our preliminary study, scintigraphy provided significant diagnostic information to differentiate benign from suspicious pulmonary nodules. The use of scintigraphy could be helpful to anticipate histological assessment and surgical treatment of SPNs identified at CT.

Adenocarcinoma↗

PubMedDate not supplied

CT evaluation of the equivocal pulmonary nodule.

In the setting of a questionable pulmonary nodule demonstrated by conventional radiographs, the place of CT in the diagnostic algorithm is not well established. We reviewed our experience in 50 consecutive patients referred to CT for a "possible pulmonary nodule." From the chest radiographs we noted nodule location, maximum dimension, presence on one or both views, and presence on a previous radiograph (greater than 1 year old), and nodules were categorized as "likely" or "unlikely" to be real parenchymal lesions based on radiographic appearance. Of a total of 56 questionable nodules, CT demonstrated no abnormality in 21 cases, parenchymal nodules in 16, scarring, atelectasis, or infiltrate in 11, and normal structural variants in 8. True pulmonary nodules were statistically significantly more frequently categorized as "likely" lesions than normal variants or no disease, but this was not of a magnitude to be clinically useful. Based on analysis of various radiographic features of equivocal nodules and their subsequent outcomes, we suggest a radiologic approach to the equivocal pulmonary nodule.

Humans↗

PubMed2000

The role of large-needle aspiration biopsy in the preoperative selection of palpable thyroid nodules: a summary of principal data.

This report summarizes clinical and pathologic data showing the role of preoperative large-needle aspiration biopsy (LNAB) histology for a better evaluation of the palpable thyroid nodules that were non-diagnostic or microfollicular at fine-needle aspiration (FNA) cytology. LNAB performed on 261 nodules with non-diagnostic cytology showed findings which were adequate for diagnosis in 130 (49.8%) and inadequate in 131 (50.2%) cases. Two hundred sixty nodules that were diagnosed as microfollicular at FNA were also examined by LNAB; inadequate specimens were obtained in 17% of cases; pure microfollicular structure was confirmed by aspiration needle biopsy in 35% of the nodules and LNAB showed the remaining 48% to contain a macrofollicular component suggesting a benign hyperplastic lesion. Seventeen nodules that were found to be microfollicular at FNA and micromacrofollicular at LNAB were excised and the postoperative result was benign in all cases. Twenty-five nodules diagnosed as microfollicular on both FNA and LNAB were excised and the postoperative diagnoses were benign (20 nodules) or malignant (five nodules). These data indicate that LNAB histology can be used for the preoperative selection of the palpable thyroid nodules that were non-diagnostic or microfollicular at FNA cytology.

Adolescent↗

PubMed2003

Effect of high sensitivity in a computerized scheme for detecting extremely subtle solitary pulmonary nodules in chest radiographs: observer performance study.

RATIONALES AND OBJECTIVES: This study investigated the effect of a high sensitivity in computer-aided diagnosis (CAD) for detecting lung nodules in chest radiographs when extremely subtle cases were presented to radiologists. MATERIAL AND METHODS: The chest radiographs used in this study consisted of 36 normal images and 54 abnormals containing solitary lung nodules, of which 25 were extremely subtle and 29 were very subtle. Receiver operating characteristic analysis for detecting lung nodules was performed without and with CAD. The levels of CAD output were simulated with a hypothetical ideal performance of 100% sensitivity, but with three or four false positives per image. Six radiologists participated in an observer study in which cases were interpreted first without and then with the use of CAD. RESULTS: The average A(z) values for radiologists without and with CAD were 0.682 and 0.808, respectively. The performance of radiologists was improved significantly when high sensitivity was used (P = .0003). However, the radiologists were not able to recognize some extremely subtle nodules (5 of 54 nodules by all radiologists), even with the correct CAD output; these nodules were then considered as non-actionable. None of 306 computer-false positives was incorrectly regarded as a nodule by all radiologists, but 63 false positives were incorrectly identified by one or more radiologists. CONCLUSION: The accuracy of radiologists in the detection of some extremely subtle solitary pulmonary nodules can be improved significantly when the sensitivity of a CAD scheme can be made to be at an extremely high level. However, all of the six radiologists failed to identify some nodules (about 10%), even with the correct output of the CAD.

Humans↗

PubMed2006

Nonsurgical approaches to the management of thyroid nodules.

Epidemiologic studies have documented substantial increases in the frequency of nodular thyroid disease. This trend is largely due to the increasing detection of nodules by the routine use of sonography in clinical practice. Only a small percentage of the nodules currently being detected will prove to be malignant. The probability of malignancy is similar in nonpalpable and palpable nodules. Fine-needle aspiration cytology has a central role in identifying malignant nodules, which are generally treated with surgery. Most thyroid nodules are cytologically benign and can be managed nonsurgically. Nodules that are completely asymptomatic require follow-up without treatment. Cosmetic problems and/or compression-related symptoms may be indications for surgery. When surgery is contraindicated or refused, several nonsurgical approaches are available. These include levothyroxine therapy, radioiodine treatment, percutaneous ethanol injections, and the new technique of laser photocoagulation. Levothyroxine therapy is the most widely used approach, but its clinical efficacy and safety are controversial. Levothyroxine might, nonetheless, be appropriate in selected cases characterized by low risk for adverse effects and nodule characteristics associated with response to this type of therapy. Radioiodine is the therapy of choice for toxic nodules or for symptomatic nodular goiters when surgery is not possible. Percutaneous ethanol injection should be used, in our opinion, as the first-line therapy only for recurrent symptomatic cystic nodules. Laser therapy should be reserved for selected patients treated in experienced centers only. With these options, clinicians can personalize the management of nodular thyroid disease according to a careful cost-benefit analysis.

Humans↗

PubMed2004

[Flat-panel detector-based computed tomography: accuracy of experimental growth rate assessment in pulmonary nodules].

PURPOSE: To determine the performance of an a-Si/CsJ flat-panel detector-based volumetric computed tomography (VCT) prototype in volumetry of synthetic nodules in a pulmonary phantom, and to assess VCT accuracy in the assessment of hypothetic tumor growth rates based on predefined tumor doubling times. METHODS: The true volumes of 50 synthetic nodules (diameter range = 1.36 - 5.34 mm) were determined and VCT volumetry was performed before and after isovolumetric deformation of the nodules. The percent measurement error (PMF) was calculated as the percent difference of the measured from the true volume. Based on the PMF, the minimum interval between two scans was determined that would be needed to depict tumor growth corresponding to the minimum number of required follow-up days (FUDs). Based on predefined tumor doubling times (VDT) FUDs were determined before and after nodule deformation. RESULTS: Measured volumes of undeformed and deformed nodules of 0.99 - 20.05 mm (3) differed significantly from corresponding true volumes (p = 0.002 - 0.004). The PMFs of these nodules significantly exceeded the values measured in larger nodules (p = 0.0001 - 0.0029). In addition, PMFs were significantly lower before than after deformation (1.33 - 7.14 % and 0.61 - 11.09 %, respectively; p = 0.002). For theoretical VDTs of 177 and 396 days, the calculated FUDs for detection of tumor growth were 19.1 and 42.7 days before deformation, and 30.2 and 67.6 days after deformation for nodules < 2 mm, respectively. CONCLUSION: VCT allows for accurate volumetry of smallest pulmonary nodules and may become a valuable clinical tool for depiction of tumor growth of even small lesions within very short scan intervals.

Data Interpretation, Statistical↗

PubMed2002

High rate of recurrence after lobectomy for solitary thyroid nodule.

OBJECTIVE: To evaluate the long-term outcome of patients treated by lobectomy for solitary thyroid nodule. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: 83 patients admitted with a clinical diagnosis of solitary thyroid nodule. INTERVENTIONS: Preoperative ultrasonography showed a solitary nodule in 32 patients and this finding was confirmed intraoperatively in 24 cases (77%). 59 patients with multinodular goitres were treated by total thyroidectomy and 24 with solitary nodule by lobectomy. MAIN OUTCOME MEASURES: Postoperative complications and freedom from nodule recurrence and/or parenchymal irregularity. RESULTS: One patient after lobectomy and 3 after total thyroidectomy developed temporary recurrent laryngeal nerve injury. Postoperative temporary hypoparathyroidism occurred in 13 patients (22%) after total thyroidectomy and in no patient after lobectomy (p = 0.02). Neither permanent recurrent laryngeal nerve injury nor permanent hypoparathyroidism occurred after either procedure. Among patients who underwent lobectomy, 6 had an adenoma and 18 had a nodular hyperplasia. At 4-year follow-up, the freedom rate from any thyroid nodule recurrence or parenchymal irregularity was 44.7%, and the freedom rate from nodular recurrence was 74%. Men tended to have a 4-year freedom rate from nodular relapse poorer than women (48% vs. 87%. p = 0.07). Nodular recurrence occurred in one patient operated on for an adenoma, and all the other recurrences occurred in patients with nodular hyperplasia. CONCLUSIONS: The mid-term freedom rate from thyroid nodule recurrence or parenchymal irregularity after lobectomy for solitary nodule of the thyroid is unsatisfactory. This observation calls for a better evaluation of long-term results after lobectomy for this condition and identification of risk factors predictive of recurrence. This would enable a more appropriate preoperative selection of patients undergoing lobectomy, indicating total thyroidectomy for those patients with solitary nodule at high risk of recurrence.

Adolescent↗

PubMed1996

Percutaneous ethanol injection of large thyroid cystic nodules.

To evaluate the effect of percutaneous ethanol injection (PEI) in the treatment of large compressive thyroid cystic nodules (TCN), we studied 20 patients, potential candidates for surgery (tracheal displacement, nodule volume over 10 mL at ultrasonography) and not cured by aspiration alone: 14 experienced a recurrence after two complete evacuations of cystic fluid (watery nodules, WN); in six an aspiration was impossible because the cystic fluid was very thick (viscous nodules, VN). To exclude malignancy, both cytocentrifugate from WN and the smears from VN were examined. WN were treated with 1-4 sessions of conventional PEI; in VN a first PEI session was performed with the purpose of reducing the density of cystic fluid; then if cystic fluid was successfully aspirated, one or more PEI sessions were performed. Thyroid palpation, ultrasonography with nodule volume assessment, and assays for FT3, FT4, and TSH were performed 1 and 6 months after the last PEI. At month 6, 17 patients (85%) had volume reduction of more than 90% of the initial nodule volume; in 2 patients (10%) there was a reduction between 50 and 90%, and in one patient (5%) an appreciable swelling persisted after 3 injections. Nodule volume was significantly decreased below baseline at month 1 (10.9 +/- 13.3 vs 39 +/- 24 mL, p < 0.001), with a further reduction at month 6 (5 +/- 11.7 mL, p < 0.01 vs 1st month value). In most of the nodules the cystic portion completely disappeared; the residual tissue showed fibrous features, often with calcifications. In 11 patients follow-up was prolonged over the sixth month (15 +/- 4 months); the nodule volume did not significantly differ from the sixth month (3 +/- 2.2 mL) and the end of the follow-up (2.8 +/- 2.3 mL). In conclusion, we demonstrate that PEI may be a safe and effective procedure in the treatment of large TCN.

Adult↗

PubMed1999

Percutaneous ethanol injection may be a definitive treatment for symptomatic thyroid cystic nodules not treatable by surgery: five-year follow-up study.

We present a prospective study on the long-term efficacy of percutaneous ethanol injection (PEI) treatment for thyroid cystic nodules. Among patients referred for symptomatic thyroid cystic nodules who had relapsed after two aspirations or whose nodules could not be aspirated due to the thickness of the cystic fluid, PEI was given when surgery was either refused or contraindicated. Forty-three patients were treated; the mean basal volume of the cysts was 38.4 mL. The purpose of the study was to evaluate long-term efficacy of PEI treatment on: (1) amelioration of symptoms and signs of local compression and (2) nodule volume reduction. In three subjects (7%), PEI failed to induce a significant (>50%) nodule reduction, so that surgical treatment was performed. In 40 patients (93%), an impressive nodule shrinkage was observed, reaching a plateau after 24 months (volume reduction = 91.9%+/-11.4%). A new PEI session was needed in two patients in whom a recurrence was noted within the first 6 months. After 6 months, no significant (> or =1 mL volume) nodule regrowth was observed up to 60 months. Both symptoms and tracheal displacement rapidly (within 1 month) and significantly (p<0.01) improved. After PEI, mild pain was the only side effect observed. No suspicious cytology was observed in any residual nodule greater than 1 mL 6 and 24 months after the last PEI session. Our data suggest that PEI is a first-line safe, effective, probably definitive, treatment for cystic thyroid nodules for which surgery is either refused or contraindicated.

Adult↗

PubMed1992

The usefulness of the dynamic phase in pertechnetate thyroid imaging for solitary hypofunctioning nodules.

One hundred patients, each with a solitary thyroid nodule detected by clinical palpation, underwent three-phase Tc-99m pertechnetate thyroid imaging. The degree of perfusion of the thyroid nodule was classified as hypo-perfused, euperfused, or hyperperfused compared to the remainder of the gland by a consensus of three nuclear medicine physicians. The nodules were subsequently biopsied, and the degree of perfusion of the nodules was correlated with their histologic diagnosis. Twenty-two nodules were classified as hyperperfused, 64 as euperfused, and 14 as hypoperfused. Malignancy rates of the hyperperfused, euperfused, and hypoperfused nodules were 36%, 31% and 0%, respectively. This seems to indicate that malignant thyroid nodules demonstrate a degree of perfusion at least equal to or greater than the rest of the thyroid gland. Conversely, none of the hypoperfused nodules was found to be malignant. The perfusion phase of thyroid imaging may provide useful clinical information regarding possible malignancy of a thyroid nodule.

Adenocarcinoma↗

PubMed1995

Radionuclide angiography in evaluation of cold solitary thyroid nodules. Improved diagnostic accuracy using flow and washout analysis.

Radionuclide thyroid angiography was performed in 252 patients with hypofunctioning thyroid nodules to evaluate differences in vascular flow and washout patterns in benign and malignant disease. Time activity curves of Tc-99m pertechnetate flow through the cold nodules were generated using region of interest software. Retention ratios of counts in the nodule at 2 minutes after radionuclide administration versus those at peak activity were derived. Patients subsequently underwent surgical excision and histopathologic examination. One hundred forty-four of the 204 benign nodules were avascular with absent radionuclide flow through the nodule. Fifty-six benign nodules were vascular with a prolonged radionuclide washout pattern with retention ratios ranging from 0.62-0.92. Forty-six of the 48 malignant nodules displayed increased perfusion with rapid radionuclide washout with retention ratios ranging from 0.28-0.48. Four benign nodules exhibited a similar flow and washout pattern. Radionuclide thyroid angiography with vascular flow and washout analysis appears to be a useful technique to differentiate between benign and malignant thyroid nodules with a high degree of sensitivity and specificity.

Adolescent↗

PubMed1997

Clinical application of Tc-99m tetrofosmin scintigraphy in patients with cold thyroid nodules. Comparison with color Doppler sonography.

We prospectively studied 26 patients with cold thyroid nodules (five malignant and 21 benign nodules) on Tc-99m pertechnetate scintigraphy to investigate the diagnostic value of Tc-99m tetrofosmin scintigraphy and color-Doppler sonography in differentiating malignant from benign thyroid nodules. In each patient, Tc-99m Tetrofosmin uptake in the nodule and intranodule vascularity were assessed semiquantatively. Both the uptake and vascularity were classified as low, Iso or high. Eight out of 26 nodules showed high Tc-99m tetrofosmin uptake; five of them were malignant. Eight (including four malignant tumors) out of 26 nodules showed increased vascularity compared with normal thyroid tissue on color-Doppler sonography. In six out of eight patients with high uptake of Tc99m-tetrofosmin, increased vascularity was observed. The sensitivity, specificity, negative predictive value, and positive predictive value of Tc-99m tetrofosmin scintigraphy and color-Doppler sonography were determined to be 100% and 80%, 85% and 80%, 62% and 50%, and 100% and 94%, respectively. We conclude that color-Doppler sonography seems to have limited value in the detection of malignant thyroid nodules. However, Tc-99m tetrofosmin scintigraphy is a sensitive method to use in diagnosing malignant nodules, although it is not specific for the detection of malignant nodules.

Adenocarcinoma, Follicular↗

PubMed1994

Computerized detection of pulmonary nodules in computed tomography images.

RATIONALE AND OBJECTIVES: Interpretation of computed tomographic (CT) scans of the lungs is a time-consuming task that involves visual correlation of possible nodules in one section with those in contiguous sections to distinguish actual nodules from blood vessels. Thus, the authors are developing automated methods to detect nodules on CT images of the thorax. METHODS: The computerized technique uses various computer-vision techniques and a priori information of the morphologic characteristics of pulmonary nodules. In each section, the external thoracic wall and lung boundaries are detected, and the features within the lung boundaries are subjected to gray-level thresholding operations. By analyzing the relationships between features arising at different threshold levels with respect to their shape, size, and location, each feature is assigned a likelihood of being a nodule or a vessel. Features in adjacent sections are compared to resolve ambiguous features. Detected nodule candidates are displayed in three dimensions within the lung. RESULTS: The system provided a sensitivity of 94% for nodule detection and an average of 1.25 false-positive results per case. CONCLUSIONS: Continued development of an automated method for detecting pulmonary nodules in CT scans is expected to aid radiologists in the task of locating nodules in three dimensions.

Artificial Intelligence↗

PubMed1999

Computed tomography halo sign in pulmonary nodules: frequency and diagnostic value.

On computed tomography (CT) scanning, a ground-glass opacity zone surrounding a pulmonary nodule has been named the computed tomography (CT) halo sign. To investigate the frequency and diagnostic value of the CT halo sign, the authors reviewed the CT examinations of 305 patients with proven diseases producing solitary or multiple nodules. The CT halo sign was seen in 22 patients (7%). Eleven patients had a solitary nodule; five patients had multiple nodules; and six patients had nodules associated with areas of pulmonary consolidation, or ground-glass opacity, or both. Solitary nodules were the result of bronchioloalveolar carcinoma (n = 5), tuberculoma (n = 2), squamous cell carcinoma, non-Hodgkin lymphoma, myxovirus infection, and metastasis (n = 1 each). Multiple nodules were the result of metastasis (n = 2), Kaposi sarcoma (n = 2), and Wegener granulomatosis (n = 1). Nodules associated with areas of consolidation or ground-glass opacity were the result of metastasis (n = 2), bronchioloalveolar carcinoma, bronchiolitis obliterans organizing pneumonia, eosinophilic pneumonia, and invasive pulmonary aspergillosis (n = 1 each). The data showed that the CT halo sign is a nonspecific finding. It is known that in immunocompromised patients the CT halo sign should suggest invasive pulmonary aspergillosis, Kaposi sarcoma, and lymphoproliferative pulmonary disorders. However, in immunocompetent patients, the authors found that a solitary nodule with the CT halo sign and pseudocavitations has a high likelihood of being a bronchioloalveolar carcinoma.

Humans↗