Manisha Bahl

Liver steatosis: investigation of opposed-phase T1-weighted liver mr signal intensity loss and visceral fat measurement as biomarkers

PURPOSE To investigate if opposed-phase T1-weighted and fat-suppressed T2-weighted liver signal intensity (SI) loss and visceral fat measurement at magnetic resonance (MR) imaging and body mass index (BMI) are correlated with grade of liver steatosis in patients with nonalcoholic fatty liver disease (NAFLD) or hepatitis C virus (HCV) and human immunodeficiency virus (HIV)-related liver disease. MATERIALS AND METHODS Committee on Human Research approval and patient consent were obtained for this HIPAA-compliant study. Fifty-two patients (15 men, 37 women) with NAFLD (n = 29) or HCV and HIV-related liver disease (n = 23) underwent prospective contemporaneous MR imaging and liver biopsy. Liver SI loss was measured on opposed-phase T1-weighted and fat-suppressed T2-weighted MR images. Visceral fat area was measured at three levels on water-suppressed T1-weighted MR images (n = 44). Spearman rank correlation coefficients and recursive partitioning were used to examine correlations. RESULTS Histopathologic liver steatosis correlated well with liver SI loss on opposed-phase T1-weighted MR images (rho = 0.78), fat-suppressed T2-weighted MR images (rho = 0.75), and average visceral fat area (rho = 0.77) (all P < .01) but poorly with BMI (rho = 0.53, P < .01). Liver SI losses on opposed-phase T1-weighted MR imaging of less than 3%, at least 3% but less than 35%, at least 35% but less than 49%, and at least 49% corresponded to histopathologic steatosis grades of 0 (n = 16 of 17), 1 (n = 11 of 16), 2 (n = 7 of 13), and 3 (n = 5 of 6), respectively. A visceral fat area of greater than or equal to 73.8 cm(2) was associated with the presence of histopathologic steatosis in 41 of 44 patients. CONCLUSION Liver SI loss on opposed-phase T1-weighted MR images and visceral fat area may be used as biomarkers for the presence of liver steatosis and appear to be superior to BMI.

How to Perform Parathyroid 4D CT: Tips and Traps for Technique and Interpretation

Parathyroid four-dimensional (4D) computed tomography (CT) is an imaging technique for preoperative localization of parathyroid adenomas that involves multidetector CT image acquisition during two or more contrast enhancement phases. Four-dimensional CT offers an alternative or additional tool in the evaluation of primary hyperparathyroidism. The purpose of this article is to describe the 4D CT technique and provide a practical guide to the radiologist for imaging interpretation. The article will discuss the rationale for imaging, approach to interpretation, imaging findings, and pitfalls.

JOURNAL CLUB: Incidental Thyroid Nodules Detected at Imaging: Can Diagnostic Workup Be Reduced by Use of the Society of Radiologists in Ultrasound Recommendations and the Three-Tiered System?

OBJECTIVE The purpose of this study was to determine the number of thyroid nodule workups that could be eliminated and the number of malignant tumors that would be missed if the Society of Radiologists in Ultrasound (SRU) recommendations and the three-tiered system were applied to incidental thyroid nodules (ITN) detected at imaging. MATERIALS AND METHODS This retrospective study included ITN in 390 consecutively registered patients who underwent ultrasound-guided fine-needle aspiration of one or more thyroid nodules from July 2010 to June 2011. Images were reviewed, and nodules were categorized according to two workup criteria: ITN seen on ultrasound images were categorized according to SRU recommendations, and those seen on CT, MR, or PET/CT images were classified according to the three-tiered risk-categorization system. RESULTS In this study 114 of 390 (29%) patients had nodules first detected incidentally during imaging studies, and 107 patients met the inclusion criteria. These patients had 47 ITN seen at ultrasound and 60 ITN seen at either CT, MRI, or PET/CT. If the SRU recommendations had been applied, 14 of 47 (30%) patients with ITN on ultrasound images would not have received fine-needle aspiration and one of four cases of cancer would have been missed. The missed malignant tumor was a 14-mm localized papillary carcinoma. If the three-tiered system had been applied, 21 of 60 (35%) patients with ITN on CT, MR, or PET/CT images would not have received fine-needle aspiration, but none of the three malignancies would have been missed. Overall, 35 of 107 (33%) of patients with ITN did not meet the SRU recommendations or the three-tiered criteria. CONCLUSION Use of the SRU recommendations and three-tiered system can reduce the workup of ITN by one third compared with current practice without specific guidelines. One case of localized papillary carcinoma was missed when the SRU recommendations were used.

Parathyroid Adenomas and Hyperplasia on Four-dimensional CT Scans: Three Patterns of Enhancement Relative to the Thyroid Gland Justify a Three-Phase Protocol

PURPOSE To describe the prevalence of three relative enhancement patterns of parathyroid lesions on four-dimensional (4D) computed tomographic (CT) scans. MATERIALS AND METHODS The institutional review board approved this HIPAA-compliant study and waived the need for informed consent. The authors retrospectively reviewed preoperative 4D CT scans obtained from November 2012 to June 2014 in 94 patients with pathologically proven parathyroid adenomas or hyperplasia. Lesions were classified into one of three relative enhancement patterns. All patterns required lesions to be lower in attenuation than the thyroid on non-contrast material-enhanced images, but patterns differed in the two contrast-enhanced phases. Type A lesions were higher in attenuation than the thyroid in the arterial phase, type B lesions were not higher in attenuation than the thyroid in the arterial phase but were lower in attenuation than the thyroid in the delayed phase, and type C lesions were neither higher in attenuation than the thyroid in the arterial phase nor lower in attenuation than the thyroid in the delayed phase. The prevalence of the relative enhancement patterns was compared. The t test was used to compare mean attenuation differences in Hounsfield units between the relative enhancement patterns. RESULTS Ninety-four patients had 110 parathyroid lesions, including 11 patients with multigland disease. The sensitivity for single-gland disease was 94% (78 of 83) and that for multigland disease was 59% (16 of 27). Type B enhancement was most common, with a prevalence of 57% (54 of 94), followed by type C (22% [21 of 94]) and type A (20% [19 of 94]). Five lesions were interpreted incorrectly as parathyroid adenoma (false-positive), and all lesions had the type C pattern. Relative to the thyroid, lesions categorized as type A by readers had mean attenuation difference (± standard deviation) of 39 HU ± 13 in the arterial phase, and type B lesions had a difference of -58 HU ± 26 in the delayed phase. These values differed from the mean attenuation difference of lesions not in these categories (P < .001). CONCLUSION Parathyroid adenomas and hyperplasia can be grouped into three relative enhancement patterns based on a protocol with a non-contrast-enhanced and two contrast-enhanced phases. The type B pattern is most common and could be diagnosed with two contrast-enhanced phases. However, almost one quarter of lesions have the type C pattern and thus could be missed without the non-contrast-enhanced phase.

Prevalence of the Polar Vessel Sign in Parathyroid Adenomas on the Arterial Phase of 4D CT

BACKGROUND AND PURPOSE: The “polar vessel” sign has been previously described on sonography of parathyroid adenomas. We estimated the 4D CT prevalence of the polar vessel sign and determined features of parathyroid adenomas that are associated with this sign. MATERIALS AND METHODS: Twenty-eight consecutive patients with parathyroid adenomas underwent 4D CT between 2008 and 2012 at 2 institutions. 4D CT images were reviewed for the presence of the polar vessel sign and a second vascular finding of an enlarged ipsilateral inferior thyroid artery. The polar vessel sign was correlated with adenoma weight and size and arterial phase CT attenuation. RESULTS: Thirty-two parathyroid adenomas in 28 patients were studied, with a mean adenoma weight of 0.66 ± 0.65 g, a mean maximal CT diameter of 11.1 ± 4.9 mm, and a mean arterial attenuation of 148 ± 47 HU. The polar vessel sign was seen in 20/32 (63%) adenomas. Adenomas with a polar vessel had higher arterial phase attenuation than adenomas without a polar vessel (163 and 122 HU, respectively, P < .01). Size and weight were not significantly different for adenomas with and without polar vessels. An enlarged inferior thyroid artery was seen in only 2/28 (7%) patients with unilateral disease. CONCLUSIONS: The polar vessel sign was present in nearly two-thirds of parathyroid adenomas on 4D CT and was more likely to be present in adenomas that had greater arterial phase enhancement. This sign can be used along with enhancement characteristics to increase the radiologists confidence that a visualized lesion is a parathyroid adenoma rather than a thyroid nodule or lymph node.

Diagnostic Value of Ultrasound in Female Patients With Nipple Discharge

OBJECTIVE The purpose of this study was to assess the contribution of ultrasound to the evaluation of patients with pathologic nipple discharge. MATERIALS AND METHODS A retrospective review was conducted of the records of females who presented with nipple discharge between January 1, 2009, and December 31, 2011. Pathologic nipple discharge was defined as discharge with one or more of the following features: unilateral, clear or bloody, and spontaneous. Patients underwent bilateral mammography followed by ultrasound directed at the subareolar portion of the affected breast. Radiologic findings and pathologic results were reviewed. RESULTS Over a 3-year period, 327 females (mean age, 48 years; range, 13-88 years) presented with nipple discharge. Among these patients, 273 (83%) underwent surgical excision or clinical or radiographic follow-up at least 2 years after presentation and composed the study population. Among the 273 patients, 262 (96%) underwent mammography and 246 (90%) underwent sonography. Among 252 patients who had at least one pathologic feature of nipple discharge and underwent surgical excision or at least 2 years of follow-up, a total of 20 (8%) cases of ductal carcinoma in situ (DCIS) or invasive adenocarcinoma were diagnosed. DCIS or invasive adenocarcinoma was diagnosed in eight patients with normal sonographic findings. For the detection of DCIS and invasive adenocarcinoma, the sensitivity and specificity of ultrasound were 56% (10/18) and 75% (170/228); the sensitivity and specificity of mammography were 15% (3/20) and 98% (237/242). CONCLUSION For females presenting with pathologic nipple discharge, ultrasound is a useful diagnostic tool and may be worth including in the routine evaluation.

Predictors of Multigland Disease in Primary Hyperparathyroidism: A Scoring System with 4D-CT Imaging and Biochemical Markers

BACKGROUND AND PURPOSE: Multigland disease represents a challenging group of patients with primary hyperparathyroidism. Additional lesions may be missed on imaging because they are not considered or are too small to be seen. The aim of this is study was to identify 4D-CT imaging and biochemical predictors of multigland disease. MATERIALS AND METHODS: This was a retrospective study of 155 patients who underwent 4D-CT and successful surgery with a biochemical cure that compared patients with multigland and single-gland disease. Variables studied included the size of the largest lesion on 4D-CT, the number of lesions prospectively identified on 4D-CT, serum calcium levels, serum parathyroid hormone levels, and the Wisconsin Index (the product of serum calcium and parathyroid hormone levels). Imaging findings and the Wisconsin Index were used to calculate a composite multigland disease scoring system. We evaluated the predictive value of individual variables and the scoring system for multigland disease. RESULTS: Thirty-six patients with multigland disease were compared with 119 patients with single-gland disease. Patients with multigland disease had significantly lower Wisconsin Index scores, smaller lesion size, and a higher likelihood of having either multiple or zero lesions identified on 4D-CT (P ≤ .01). Size cutoff of <7 mm had 85% specificity for multigland disease, but including other variables in the composite multigland disease score improved the specificity. Scores of ≥4, ≥5, and 6 had specificities of 81%, 93%, and 98%, respectively. CONCLUSIONS: The composite multigland disease scoring system based on 4D-CT imaging findings and biochemical data can identify patients with a high likelihood of multigland disease. Communicating the suspicion for multigland disease in the radiology report could influence surgical decision-making, particularly when considering re-exploration in a previously operated neck or initial limited neck exploration.

Parathyroid 4D CT and Scintigraphy: What Factors Contribute to Missed Parathyroid Lesions?

Objective To determine the prevalence of missed lesions for parathyroid 4-dimensional computed tomography (4D CT) and scintigraphy and to describe the factors leading to missed lesions for both modalities. Study Design Case series with chart review. Setting Single center, hospital based. Subjects and Methods Forty patients undergoing 4D CT and scintigraphy before parathyroidectomy between July 2009 and October 2013 were included. Radiology reports and imaging were reviewed and correlated with operative notes to identify cases with missed lesions and the reasons for those misses. All lesions were then classified according to the following factors: multigland disease, lesion size, patient body weight, and multinodular goiter. Results Of the 40 patients, 6 had multigland disease, resulting in 51 lesions; 12 and 29 lesions were missed on 4D CT and scintigraphy, respectively. The sensitivity for detection of all lesions was 76% for 4D CT and 43% for scintigraphy. Sensitivities for single-gland disease were 88% for 4D CT and 50% for scintigraphy. Sensitivities for multigland disease were 53% for 4D CT and 24% for scintigraphy. Rates of multigland disease in patients with missed lesions were 75% on 4D CT and 48% on scintigraphy, as compared with patients with detected lesions, 23% and 18%, respectively (P ≤ .04). Mean weight of lesions missed on 4D CT was 0.3 and 0.6 g in detected lesions (P = .15). Mean weight of lesions missed on scintigraphy was 0.4 and 0.8 g in detected lesions (P = .03). Conclusion 4D CT has higher sensitivity than scintigraphy. Missed lesions are more likely to occur with multigland disease for both modalities and in smaller lesions for scintigraphy.

Imaging-Detected Incidental Thyroid Nodules that Undergo Surgery: A Single-Center Experience Over 1 Year

The authors describe the imaging and pathology results of 47 patients who underwent surgery for incidentally found thyroid nodules. All patients had biopsies before surgery but only 4% of these showed benign processes. Surgery eventually demonstrated that 51% of nodules were benign and when malignant the most common histology was papillary type. BACKGROUND AND PURPOSE: Incidental thyroid nodules are commonly seen on imaging, and their work-up can ultimately lead to surgery. We describe characteristics and pathology results of imaging-detected incidental thyroid nodules that underwent surgery. MATERIALS AND METHODS: A retrospective review was performed of 303 patients who underwent thyroid surgery over a 1-year period to identify patients who presented with incidental thyroid nodules on imaging. Medical records were reviewed for the types of imaging studies that led to detection, nodule characteristics, and surgical pathology. RESULTS: Of 303 patients, 208 patients (69%) had surgery for thyroid nodules. Forty-seven of 208 patients (23%) had incidental thyroid nodules detected on imaging. The most common technique leading to detection was CT (47%). All patients underwent biopsy before surgery. The cytology results were nondiagnostic (6%), benign (4%), atypia of undetermined significance or follicular neoplasm of undetermined significance (23%), follicular neoplasm or suspicious for follicular neoplasm (19%), suspicious for malignancy (17%), and diagnostic of malignancy (30%). Surgical pathology was benign in 24 of 47 (51%) cases of incidental thyroid nodules. In the 23 incidental cancers, the most common histologic type was papillary (87%), the mean size was 1.4 cm, and nodal metastases were present in 7 of 23 cases (30%). No incidental cancers on imaging had distant metastases. CONCLUSIONS: Imaging-detected incidental thyroid nodules led to nearly one-fourth of surgeries for thyroid nodules, and almost half were initially detected on CT. Despite indeterminate or suspicious cytology results that lead to surgery, more than half were benign on final pathology. Guidelines for work-up of incidental thyroid nodules detected on CT could help reduce unnecessary investigations and surgery.

Thyroid Cancers Incidentally Detected at Imaging in a 10-year Period: How Many Cancers Would Be Missed with Use of the Recommendations from the Society of Radiologists in Ultrasound?

PURPOSE To estimate the prevalence of incidental thyroid cancer (ITC) among patients undergoing thyroid surgery and to apply the Society of Radiologists in Ultrasound (SRU) guidelines to ITC. MATERIALS AND METHODS This HIPAA-compliant study was approved by the institutional review board, with waiver of the need to obtain informed consent. A retrospective review of data in patients who underwent thyroid surgery between January 1, 2003, and December 31, 2012, was performed. Imaging studies and reports were reviewed for ITCs that were first detected at either ultrasonography (US) or a different imaging modality and that included US as part of the work-up. ITCs were categorized by using the SRU guidelines to determine the characteristics of SRU criteria-positive and SRU criteria-negative malignancies. Patient demographic data, tumor histologic findings, tumor size, and tumor stage were compared for the SRU criteria-positive and SRU criteria-negative cancers by using the unpaired t test and the χ(2) test. RESULTS Among 2090 patients who underwent thyroid surgery, 680 had thyroid cancer; of these patients, 101 (15%) had imaging-detected ITC. The SRU recommendations were applied to the findings in 90 of the 101 patients who had undergone US with images or had reports available for review. Sixteen (18%) of the 90 patients had SRU criteria-negative tumors, which represented 2% (16 of 680) of all thyroid cancers. SRU criteria-negative tumors were smaller than SRU criteria-positive tumors (mean, 1.1 cm [range, 0.9-1.4 cm] vs mean, 2.5 cm [range, 1.0-7.6 cm]; P < .001) and were more likely to be stage I (15 [94%] of 16 vs 47 [64%] of 74; P = .02). CONCLUSION Imaging-detected ITCs are uncommon. Two percent (16 of 680) of malignancies would not undergo fine-needle aspiration biopsy or surgery if the SRU guidelines were used for work-up of incidental thyroid nodules. SRU criteria-negative tumors are lower in stage than SRU criteria-positive tumors.