Initial Clinical Images From a Second-Generation Prototype Silicon-Based Photon-Counting Computed Tomography System

RATIONALE AND OBJECTIVES

To demonstrate the feasibility and potential of using a second-generation prototype photon-counting computed tomography (CT) system to provide simultaneous high spatial resolution images and high spectral resolution material information across a range of routine imaging tasks using clinical patient exposure levels.

MATERIALS AND METHODS

The photon-counting system employs an innovative silicon-based photon-counting detector to provide a balanced approach to ultra-high-resolution spectral CT imaging. An initial cohort of volunteer subjects was imaged using the prototype photon-counting system. Acquisition technique parameters and radiation dose exposures were guided by routine clinical exposure levels used at the institution. Images were reconstructed in native slice thickness using an early version of a spectral CT reconstruction algorithm Samples of images across a range of clinical tasks were selected and presented for review.

RESULTS

Clinical cases are presented across inner ear, carotid angiography, chest, and musculoskeletal imaging tasks. Initial reconstructed images illustrate ultra-high spatial resolution imaging. The fine detail of small structures and pathologies is clearly visualized, and structural boundaries are well delineated. The prototype system additionally provides concomitant spectral information with high spatial resolution.

CONCLUSION

This initial study demonstrates that routine imaging at clinically appropriate patient exposure levels is feasible using a novel deep-silicon photon-counting detector CT system. Furthermore, a deep-silicon detector may provide a balanced approach to photon-counting CT, providing high spatial resolution imaging with simultaneous high-fidelity spectral information.

Unveiling the Potential of Venn Diagrams as a Helpful Tool for Clinical Reasoning: An Illustrative Case-based Discussion

Venn diagrams graphically represent a cognitive approach that can assist in highlighting information shared by different data sets while eliminating nonoverlapping conditions. When applied to clinical reasoning, such an approach helps physicians visually focus on data pertaining to differential diagnoses. We present and discuss a 3-step reasoning pathway derived from a real-life case in which we used Venn diagrams to diagnose drug-related pneumonitis in a 67-year-old man with advanced bladder cancer and nodular lung findings at chest CT. This education paper supports using Venn diagrams in Radiology.

Cross-sectional imaging review of common to uncommon lung cancer mimickers in a tertiary care oncology center

Lung cancer is the most diagnosed cancer worldwide. Many non-malignant pulmonary lesions, such as tuberculosis, fungal infection, organizing pneumonia, inflammatory myofibroblastic tumor, and IgG4 disease, can mimic lung cancer due to their overlapping morphological appearance on imaging. These benign entities with minor differentiating imaging clues may go unnoticed in a high-volume cancer institution, leading to over-investigation that may result in repeated biopsies, pointless wedge resections, and related morbidities. However, with a thorough medical history, laboratory diagnostic work-up, and careful analysis of imaging findings, one can occasionally restrict the range of possible diagnoses or arrive at a definitive conclusion. When imaging features overlap, image-guided lung sampling is crucial since histopathological analysis is the gold standard.

Growth Rates of Pulmonary Carcinoid Tumors and Hamartomas

BACKGROUND

Pulmonary nodule growth is often measured by volume doubling time (VDT), which may guide management. Most malignant nodules have a VDT of 20 to 400 days, with longer VDTs typically observed in indolent nodules. We assessed the utility of VDT in differentiating pulmonary carcinoids and hamartomas.

METHODS

A review was performed from January 2012 to October 2021 to identify patients with pathologic diagnoses and at least 2 chest computed tomography scans obtained 6 or more months apart. Visualization software was used to segment nodules and calculate diameter and volume. Volume doubling time was calculated for scans with 1-mm slices. For the remainder, estimated nodule volume doubling time (eVDT) was calculated using nodule diameter. Volume doubling times/eVDTs were placed into growth categories: less than 400 days; 400-600 days; and more than 600 days.

RESULTS

Sixty nodules were identified, 35 carcinoids and 25 hamartomas. Carcinoids were larger than hamartomas (median diameter, 13.5 vs 11.5 mm; P = 0.05). For carcinoid tumors, median VDT (n = 15) was 1485 days, and median eVDT (n = 32) was 1309 days; for hamartomas, median VDT (n = 8) was 2040 days and median eVDT (n = 25) was 2253 days. Carcinoid tumor eVDT was significantly shorter than hamartomas ( P = 0.03). By growth category, 1 of 25 hamartomas and 5 of 35 carcinoids had eVDT less than 400 days and 24 of 25 hamartomas and 27 of 35 carcinoids had eVDT more than 600 days. Of 4 carcinoid tumors with metastases, 2 had eVDT less than 400 days and 2 had eVDT more than 600 days.

CONCLUSIONS

Growth rate was not a reliable differentiator of pulmonary hamartomas and carcinoids. Slow growing carcinoids can metastasize. Radiologists should be cautious when discontinuing computed tomography follow-up based on growth rates alone.

Adenosquamous carcinoma lung radiologically mimicking pneumonia: A potentially disastrous diagnostic challenge in an unusual malignancy

Lung cancer is among the most frequently diagnosed cancers and the world's leading cause of cancer-related death. Radiology remains the mainstay for timely diagnosis; however, atypical radiologic patterns are known, and these may be misdiagnosed as infectious or inflammatory pathology, particularly in the absence of smoking history. We report herein an account of an older male nonsmoker who presented radiologically with bilateral diffuse pulmonary infiltrates, simulating pneumonia, but was eventually diagnosed with adenosquamous lung carcinoma. The delay in diagnosis and subsequent unfortunate rapid deterioration of our patient serves as a reminder for clinicians to consider lung cancer in patients with clinical/radiologic findings suggestive of pneumonia, especially in nonsmokers or cases refractory to antibiotic therapy.

Outcomes for Elective Open and Thoracoscopic Surgical Lung Biopsies in the United States and Temporal Trends

Objective

To elucidate the outcomes of surgical lung biopsies (SLBs) performed for indications other than interstitial lung disease (ILD) and stratify outcomes according to procedural approach (open vs thoracoscopic).

Patients and Methods

Using the Nationwide Inpatient Sample database (January 1, 2008, through December 31, 2014), we identified elective hospitalizations with International Classification of Diseases, Ninth Revision, Clinical Modification codes for open (33.28) and thoracoscopic (33.20) SLB. We stratified cases by the presence/absence of ILD. Our primary outcome was in-hospital mortality.

Results

There were 47,469 hospitalizations for elective SLB (26,540 [55.9%] thoracoscopic) during the study period; 23,930 patients (50.5%) were women, 17,019 (35.9%) had ILD, and the mean ± SD age was 62.6±13.0 years. Over the study period, thoracoscopic increasingly replaced open SLB, and in-hospital mortality declined (3.5% [308 of 8678] in 2008 vs 2.5% [130 of 5215] in 2014; P<.001). Mortality following thoracoscopic SLB was 2.1% (550 of 26,519; 1.9% [214 of 11,513] in ILD and 2.2% [336 of 15,006] in non-ILD), and mean ± SD length of stay was 5.1±6.9 days. Open SLBs had worse outcomes; mortality was 3.7% (782 of 20,914; 3.9% [214 of 5487] in ILD and 3.7% [568 of 15,427] in non-ILD), and mean ± SD length of stay was 8.2±12 days. On multivariable analysis, male sex, advanced age, ILD, and higher comorbidity index correlated with higher mortality. Conversely, lower mortality was observed among individuals with obesity (odds ratio, 0.73; 95% CI, 0.60-0.88) and those who had their thoracoscopic SLBs performed at high-volume centers (top quartile) (odds ratio, 0.73; 95% CI, 0.57-0.94).

Conclusion

Surgical lung biopsy is more often performed for non-ILD indications. Interstitial lung disease was an independent predictor of poor outcomes, but the unadjusted outcomes were worse in the non-ILD cohort due to differences in patient characteristics. Thoracoscopic SLBs performed at high-volume centers had superior outcomes.

Cocaine-induced pulmonary complications: A diagnosis of waiting and watching

Pulmonary complications of cocaine among users are common. Manifestations include lung congestion, intra-alveolar edema, and diffuse alveolar hemorrhage (DAH). Direct cellular toxicity, eosinophilia, barotrauma, and vasoactive effects of cocaine are believed to induce DAH. We present a rare case of cocaine-associated focal alveolar hemorrhage mimicking malignancy on imaging. Initially contemplated biopsy was avoided based on rapid growth of concerning lung lesion, with subsequent near resolution on follow-up. This case illustrates the importance of epidemiologic and temporal multimodality correlation when evaluating indeterminate lung lesions.

Rare pulmonary tumors and carcinoma mimickers; experience from an interventional radiology unit with radiologic-pathologic correlation-A pictoral essay

BACKGROUND

Although imaging findings along with patients' clinical history may give clue for the etiology of a pulmonary lesion, the differentiation of benign pulmonary lesions from lung cancer could be challenging.

OBJECTIVE

The aim of this review article was to increase the awareness of the carcinoma mimicking lung lesions.

METHODS

This paper was designed to illustrate rare pulmonary tumors and carcinoma mimickers with emphasis on radiologic-pathologic correlation. Pitfalls encountered on CT images and also false positivity of PET-CT scans were also presented.

CONCLUSION

Several benign pulmonary lesions may grow in size on follow-up and some may show pathologic FDG (18F-fluorodeoxyglucose) uptake, which makes them indistinguishable from lung carcinoma by imaging. In addition, some slow-growing malignant lesions, such as carcinoid, may be false-negative on PET/CT scans.

Pulmonary carcinomas arising in association with scar: Cytomorphologic features in histologically confirmed cases

BACKGROUND

Lung carcinoma arising in association with scar tissue is a well-reported but much debated phenomenon. Scar tissue complicates imaging and pathologic tumor measurement for cancer staging. To the best of our knowledge, the cytological findings in lung scar carcinoma (LSC) have not been described in the literature. Therefore, the aim of this study was to characterize the findings in fine-needle aspirations (FNA) from histologically confirmed LSCs.

METHODS

LSCs were identified on retrospective search. Cases with preoperative FNA material were reviewed, including non-scar cases that were used for comparison. The clinical and histopathology findings were recorded.

RESULTS

Twenty-seven cases associated with scar tissue had material for review and 35 cases not associated with scar tissue were used for comparison. The proportion of fibrosis in resection specimens ranged from 10% to 80%. Five (19%) FNA cases were hypocellular. There was no statistically significant difference between the scar and non-scar groups in terms of overall cellularity and diagnostic categories (P = .113 and P = .17, respectively). There was correlation between cytology and dominant pattern on histology in 19 (79%) adenocarcinoma cases. Spindle cells and fibrous or fibroelastotic fragments were present in 22 (81%) cases.

CONCLUSION

This is the first study describing the cytology associated with LSCs. The presence of fibrosis did not adversely impact cellularity, which is likely due to multiple excursions and selective microdissection of tumor cells by the FNA needle. The cytomorphological and histological patterns correlated in most cases. FNA is able to provide a preoperative diagnosis of carcinoma despite the presence of fibrosis.

Management of Pulmonary Nodules in Oncologic Patients: AJR Expert Panel Narrative Review

Cancer survivors are at higher risk than the general population for development of a new primary malignancy, most commonly lung cancer. Current lung cancer screening guidelines recommend low-dose chest CT for high-risk individuals, including patients with a history of cancer and a qualifying smoking history. However, major lung cancer screening trials have inconsistently included cancer survivors, and few studies have assessed management of lung nodules in this population. This narrative review highlights relevant literature and provides expert opinion for management of pulmonary nodules detected incidentally or by screening in oncologic patients. In patients with previously treated lung cancer, a new nodule most likely represents distant metastasis from the initial lung cancer or a second primary lung cancer; CT features such as nodule size and composition should guide decisions regarding biopsy, PET/CT, and CT surveillance. In patients with extrapulmonary cancers, nodule management requires individualized risk assessment; smoking is associated with increased odds of primary lung cancer, whereas specific primary cancer types are associated with increased odds of pulmonary metastasis. Nonneoplastic causes, such as infection, medication toxicity, and postradiation or postsurgical change, should also be considered. Future prospective studies are warranted to provide evidence-based data to assist clinical decision-making in this context.

A retrospective study on the clinical characteristics and radiological features of primary pulmonary lymphoma

Background

The retrospective study was mainly performed to determine the clinical symptoms and radiological characteristics of primary pulmonary lymphoma (PPL) to improve the recognition and diagnosis of the disease.

Methods

Between June 2007 and June 2019, the clinical data and radiological images of the 16 patients with PPL confirmed by pathology were retrospectively analyzed.

Results

Among the 16 patients with PPL (6 males and 10 females, aged 32 to 72 years, with a median age of 55.13 years), 9 patients were mucosa-associated lymphoid tissue lymphoma (MALT) and 7 patients were diffuse large B-cell lymphoma (DLBCL); all of the patients did not suffer from autoimmune disease [such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), or Sjogren’s syndrome (SSS)]; and 11 patients had a long-term smoking history from 10 to 40 years. The common clinical symptoms were as follows: chest discomfort (n=8), cough (n=10), chest pain (n=7), fever (n=6), apnea (n=1), fatigue (n=4) and weight loss (n=3), however, 6 cases did not show clear symptoms at the time of diagnosis. Blood tests revealed anemia (n=6), thrombocytopenia (n=2), lactate dehydrogenase (LDH) level (n=7), C-reactive protein (CRP) (n=9), erythrocyte sedimentation rate (ESR) (n=8) and no tumor-related indexes were detected abnormal. The chest radiological images showed a total of 8 cases with multiple masses, 2 cases with different types of nodes, 4 cases with patchy infiltration or consolidation shadow, with or without an air bronchogram, and 2 cases with a mixed manifestation. All the lesions were only involved in unilateral lung (13 right, 3 left), none of them located on bilateral lung fields. At the time of admission, the patients were misdiagnosed as lung cancer (n=9), pneumonia (n=5), tuberculosis (n=1), and diffuse interstitial lung disease (n=1). Then final pathological diagnosis was confirmed by surgery (n=9), percutaneous lung biopsy (n=5), and bronchoscopic biopsy (n=2).

Conclusions

PPL is a rare disease, though clinical symptoms and radiological characteristics are not typical, they serve as significant clues for the diagnosis and differential diagnosis. Accurate diagnosis mainly depends on histopathological examination, however, conducting a retrospectively study could improve and enrich our knowledge to the disease and reduce inappropriate treatments.

Tumor Atelectasis Gives Rise to a Solid Appearance in Pulmonary Adenocarcinomas on High-Resolution Computed Tomography

Introduction

Ground-glass opacities in a high-resolution computed tomography (HR-CT) scan correlate, if malignant, with adenocarcinoma in situ. The solid appearance in the HR-CT is often considered indicative of an invasive component. This study aims to compare the radiologic features revealed in the HR-CT and the histologic features of primary adenocarcinomas in resection specimens to find the presence of tumor atelectasis in ground-glass nodules (GGNs) and part-solid and solid nodules.

Methods

HR-CT imaging was evaluated, and lung nodules were classified as GGNs, part-solid nodules, and solid nodules, whereas adenocarcinomas were classified according to WHO classification. Lepidic growth pattern with collapse was considered if there was reduction of air in the histologic section with maintained pulmonary architecture (without signs of pleural or vascular invasion).

Results

Radiologic and histologic features were compared in 47 lesions of 41 patients. The number of GGN, part-solid, and solid nodules were two, eight, and 37, respectively. Lepidic growth pattern with collapse was observed in both GGN, seven of the eight part-solid (88%) and 24 of the 37 solid (65%) lesions. Remarkably, more than 50% of the adenocarcinomas with a solid appearance in HR-CT imaging had a preexisting pulmonary architecture with adenocarcinoma with a predominant lepidic growth pattern. In these cases, the solid component can be explained by tumor-related collapse in vivo (tumor atelectasis on radiologic examination).

Conclusions

Tumor atelectasis is a frequent finding in pulmonary adenocarcinomas and may beside a ground glass opacity also result in a solid appearance in HR-CT imaging. A solid appearance on HR-CT cannot be attributed to invasion alone, as has been the assumption until now.

Lung Masses of Unusual Histologies Mimicking Malignancy: Flurodeoxyglucose Positron Emission Tomography-Computed Tomography Appearance

18F flurodeoxyglucose positron emission tomography-computed tomography (18F FDG PET-CT) is widely used in the evaluation of patients with lung mass suspicious for malignancy. In addition to malignancy, a variety of benign neoplasms and inflammatory lesions can arise in the lungs, many of which show increased FDG concentration, thereby mimicking malignancy. Awareness of the common mimics of lung cancer and a thorough understanding of their key imaging characteristics on CT as well as FDG PET is helpful in narrowing the differential diagnosis, eventually leading to appropriate therapy. In this article, we enlist these mimics and discuss their metabolic and morphologic characteristics and provide a pathophysiological basis for their FDG uptake.

[Mimics of lung cancer]

Lung cancer is a histologically, immunologically and therefore morphologically and functionally very heterogeneous group of neoplasms with the highest cancer mortality worldwide. Therefore, the range of diseases mimicking lung cancer is also very broad and includes congenital, infectious and inflammatory changes as well as other benign space-occupying lesions and other primary and secondary pulmonary neoplasms. The difficulty in radiology lies in the ability to diagnose lung cancer with a high degree of certainty. This must take the limits of the specific diagnosis, knowledge of the classical pitfalls and rare entities that can imitate lung cancer into consideration. Narrowing the differential diagnosis requires close interdisciplinary cooperation and consideration of the patient's clinical and medical history. An accurate analysis of the computed tomography (CT) pattern and distribution of the lesions as well as consideration of additional changes and involvement of other organ systems can be the key to the diagnosis. The use of fluorodeoxyglucose positron-emission tomography CT (FDG-PET-CT) is helpful only in a few mimics of lung cancer. The article describes clinical and radiological findings of mimics of lung cancer also pointing out the limitations of CT and PET-CT for the diagnosis.

Solitary round pulmonary lesions in the pediatric population: a pictorial review

The purpose of this current pictorial review is to define the solitary round pulmonary lesion (SRPL), to familiarize with its prevalence in the pediatric population, and, moreover, to educate radiologists on its vast differential diagnosis and imaging manifestations. Furthermore, by highlighting valuable clues, it intends to assist radiologists efficiently partake in its diagnosis, work-up, and follow-up in order to narrow down the differential diagnosis by working alongside the clinician and combining clinical information, lab results, and radiological findings.

A case of pulmonary tuberculosis with multiple nodules mimicking lung metastases

Tuberculosis (TB) may present as multiple pulmonary nodules mimicking lung metastases. Many asymptomatic cases of TB are detected incidentally on chest radiography, and patients are often negative for acid-fast bacilli staining and culture in spite of having active TB. It is important to know the imaging findings characteristic of pulmonary TB and its variant forms. Multiple pulmonary nodules were detected in an 80-year-old female during a medical checkup. TB was not suspected until her imaging findings worsened; however, in retrospect, centrilobular micronodules were observed amongst multiple well-circumscribed nodules on the initial images and worsened during conservative management. Although bilateral multiple well-circumscribed pulmonary nodules are suggestive of metastases, when a nodule surrounded by centrilobular or satellite micronodules is found, even in the absence of characteristic findings such as cavitation or the tree-in-bud sign, pulmonary TB should be considered in the differential diagnosis to prevent delays in treatment.

Hamartomas from head to toe: an imaging overview

Hamartomas are tumours composed of mesenchymal tissues such as cartilage, fat, connective tissue and smooth muscle and can be found in virtually any organ system. These masses commonly develop sporadically, but are also seen in certain syndromes such as tuberous sclerosis or Carney triad. While their imaging appearance varies depending on the organ they arise from, findings are usually unique and a diagnosis can be confidently made. Radiologists must be aware of the clinical and imaging presentations of these lesions with the particular goal of avoiding unnecessary studies or invasive procedures. Furthermore, knowledge of common syndromic entities is crucial, as the radiologist may be the first to suggest the diagnosis.

Thoracic Myoepithelial Tumors: A Pathologic and Molecular Study of 8 Cases With Review of the Literature

Thoracic myoepithelial tumors (MTs) are a rare group of tumors showing predominant or exclusive myoepithelial differentiation. They are poorly characterized from both a morphologic and genetic standpoint, in particular features that separate benign from malignant behavior. We examined the histologic and immunohistochemical features of 8 primary thoracic MTs and performed fluorescence in situ hybridization for EWSR1, FUS, PLAG1, and HMGA2, as well as several partner genes. Half (4/8) of the MTs occurred in large airways, and 3 had infiltrative borders. All cases showed immunoreactivity for epithelial markers, in conjunction with S100 protein or myogenic markers. MTs showed morphologic characteristics analogous to MTs at other sites, with no tumors having ductal differentiation. Necrosis and/or lymphovascular invasion was present in 5 cases, with mitotic activity ranging from 0 to 6 mitoses/2 mm² (mean 1). Metastases occurred in 2 cases, and no patients died of disease. Gene rearrangements were identified in half of the cases, with EWSR1-PBX1, EWSR1-ZNF444, and FUS-KLF17 fusions identified in 1 case each and 1 case having EWSR1 rearrangement with no partner identified. No cases were found to have HMGA2 or PLAG1 abnormalities. Compared with fusion-negative tumors, fusion-positive tumors tended to occur in patients who were younger (50 vs. 58 y), female (1:3 vs. 3:1 male:female ratio), and demonstrated predominantly spindle and clear cell morphology. Using a combined data set of our case series with 16 cases from the literature, poor prognosis was significantly correlated with metastases (P=0.003), necrosis (P=0.027), and ≥5 mitoses/2 mm²/10 high-power field (P=0.005). In summary, we identify a subset of thoracic MTs harboring rearrangements in EWSR1 or FUS, and our data suggest that necrosis and increased mitotic activity correlate with aggressive clinical behavior.

Malignancies incidentally detected at lung transplantation: radiologic and pathologic features

OBJECTIVE

The purpose of this study was to assess the CT-pathologic features of cancer incidentally detected at lung transplantation.

MATERIALS AND METHODS

Our lung transplant registry was reviewed over 7 years for incidental malignancy. Patient demographics, diffuse lung disease, surgical procedure, histopathology, and chest CT were recorded. We correlated lesion size, morphology, multiplicity, and location with surgical and pathology reports and histopathology. Cancers were pathologically staged.

RESULTS

Of 759 lung transplant recipients, cancer was incidentally detected in 22 (2.9%). Half (11 of 258) or 4.3% were detected within the past 2 years. Four patients had a history of treated malignancy, and three had recurrence. Patients had emphysema (chronic obstructive pulmonary disease [COPD]) (n = 10), fibrosis (n = 10), or combined COPD and fibrosis (n = 2). Histopathology revealed 13 solitary lung carcinomas, four multifocal adenocarcinomas, three metastases, and two lymphoproliferative diseases. Lung cancer (n = 17) stages were I or II (n = 13), IIIA (n = 2), or IV (n = 2). Metastases (n = 3) and lymphoproliferative disease (n = 2) represented advanced disease. The interval between CT and surgery was a mean of 4 months. CT-positive cases (n = 10) represented lung cancer (n = 9) and posttrans-plantation lymphoproliferative disease (n = 1). Cases with no CT findings of malignancy (n = 12) included lung cancer (n = 8), metastases (n = 3), and lymphoma (n = 1). Ten cases (45%) had other histologically benign CT abnormalities that mimicked cancer.

CONCLUSION

Detection of incidental malignancy at lung transplantation has increased over the past 2 years. Malignancies were typically stage I or II lung cancers that were occult or indeterminate on CT. Diffuse lung disease, multiple CT abnormalities, and a delay between CT and transplantation compromise the preoperative diagnosis of cancer.