Comparison of diagnostic accuracy of ultra low-dose computed tomography and X-ray of the kidneys, ureters and bladder for urolithiasis in the follow-up setting.

INTRODUCTION: Urolithiasis is frequently followed up with a low-dose computed tomography of the kidneys ureters and bladder (LD-CTKUB) with doses typically less than 3 millisieverts. Although X-ray is a lower dose (0.5-1.1 mSv) alternative for follow up, it has lower diagnostic accuracy and is limited to radiopaque calculi. This study aims to compare the diagnostic accuracy of sub-millisievert ultra-low dose CT (ULD-CTKUB) against X-ray KUB for the follow up of urolithiasis when both are compared against the standard of care of a low-dose CT KUB (LD-CTKUB). METHODS: This prospective study included patients with a known diagnosis of urolithiasis on prior CTKUB presenting for follow up. Each patient underwent a repeat reference LD-CTKUB, ULD-CTKUB and X-ray KUB. All imaging studies were interpreted by three readers. The radiation dose and quantitative noise was calculated for each CT. Both CT and X-ray were assessed for the presence, number and size of all calculi ≥2 mm. RESULTS: A total of 58 patients were included in this study. LD-CTKUB identified 197 calculi. ULD-CTKUB in our study had a mean effective dose of 0.5 mSv compared to X-ray KUB where doses range in the literature from 0.5 to 1.1 mSv. Per-patient pooled analysis for intrarenal calculi when comparing ULD-CTKUB versus X-ray KUB against a reference LD-CTKUB found a sensitivity of 90% versus 67% (P < 0.01) and specificity of 93% versus 98% (P = 0.18) respectively. For ureteric calculi, the sensitivity was 67% versus 33% (P < 0.01) and specificity 94% versus 94% (P = 1.00) respectively. Per-stone pooled analysis detection rate was 79% for ULD-CTKUB versus 48% for X-ray (P < 0.01) when each was compared to the reference LD-CTKUB. Interobserver agreement was high for intrarenal calculi and moderate for ureteric calculi. CONCLUSION: Sub-millisievert ULD-CTKUB had lower doses and higher sensitivity than X-ray in patients requiring follow up of known urolithiasis.

Prediction of low DEXA T-scores by routine computed tomography body scans at different kilovoltage peaks.

INTRODUCTION: Previous studies have demonstrated positive correlations between computed tomography (CT) attenuation of lumbar spine vertebrae and their bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DEXA). However, these studies were performed using a standard 120 kilovoltage peak (kVp) setting. As radiation attenuation in mineralised tissues varies by the tube voltage applied, we determined the diagnostic accuracy of CT attenuation at identifying individuals with low BMD at different kVp settings. METHODS: Single centre retrospective study of adults who had CT and DEXA scans within 6 months of each other. CT scans were performed at either 100 kVp, 120 kVp or dual energy (80 kVp/140 kVp). Attenuation was measured in axial cross-sections of L1-4 vertebrae and correlated with the results of DEXA. Receiver operated characteristic (ROC) curves were generated to determine diagnostic cut-off thresholds. RESULTS: Analysis included 268 subjects (169 females; mean age: 70, range: 20-94 years). CT attenuation values at L1 or mean L1-4 correlated positively with DEXA-derived T-scores. At L1, the optimal Hounsfield units (HU) thresholds for predicting DEXA T-scores of -2.5 or less at 100 kVp, 120 kVp and dual-energy scans were <170, <128 and <164, with corresponding AUCs of 0.925, 0.814 and 0.743 respectively. For mean L1-4, the HU thresholds were <173, <134 and <151, with corresponding AUCs of 0.933, 0.824 and 0.707 respectively. CONCLUSION: CT attenuation thresholds differ depending on the tube voltage used. We provide voltage-specific, probability-optimised thresholds for the identification of persons likely to have low BMD on DEXA scanning.

A tale of two twists: mesentero-axial and organo-axial sigmoid volvulus.

INTRODUCTION: Sigmoid volvulus is a potentially devastating and life-threatening condition associated with sigmoid colon redundancy. Many of the classical radiological signs are considered to represent the two adjacent loops of bowel in a mesentero-axial volvulus. However, limited case reports and series have reported on an organo-axial subtype of sigmoid volvulus. This clinical entity is not widely understood. In this study, we assess the radiological and clinical features of mesentero-axial and organo-axial sigmoid volvulus. METHODS: After institutional board approval (CH62/6/2016-228), all computed tomography (CT) studies from 2011 to 2017 reported as sigmoid volvulus at a single institution were reviewed. The cases were reviewed by three radiologists retrospectively and the course of the bowel followed with a focus on assessing its rotational axis. In each case, the sigmoid volvulus was independently subclassified as mesentero-axial or organo-axial volvulus based on the axis of rotation of the volvulus. In addition, X-ray signs including disproportionate sigmoid dilatation, distended inverted 'U' in sigmoid, coffee bean sign, opposed wall sign, direction of apex of sigmoid loop, liver overlap sign, northern exposure sign and proximal colonic dilatation and CT features including whirl sign, 'X' marks the spot sign, split wall sign and number of transition points were reported for each case. The clinical management and outcomes including morbidity, mortality, endoscopic decompression and need for surgery were also evaluated. The subtype of volvulus was correlated with the above X-ray signs, CT features and clinical management and outcomes. Statistical analysis was conducted using Stata/MP, version 15 (StataCorp LP, College Station, TX, USA). RESULTS: A total of 38 scans were reviewed. There were 19 patients identified. Of these, six (32%) were reported as mesentero-axial and 13 (68%) as organo-axial volvulus. No X-ray signs were able to distinguish the two types of volvulus. The number of transition points on CT was predictive of volvulus subtype (OR 25, 95% CI: 1.30-1295.30, P = 0.01). Within the limitations of a small cohort, there was no statistically significant difference in unsuccessful endoscopic decompression, need for colectomy, repeated admissions or mortality between the groups. CONCLUSION: This study has demonstrated that organo-axial sigmoid volvulus may be as common as mesentero-axial volvulus. Distinguishing organo-axial from mesentero-axial volvulus can be achieved on CT, but not on abdominal X-ray. The number of transition points (two for mesentero-axial and one for organo-axial) may be used as a diagnostic feature for differentiating the two forms of volvulus.

Cardiac manifestations of IgG4-related disease: a case series.

Background: IgG4-related disease (IgG4-RD) is an autoimmune condition affecting almost every organ system, with an early inflammatory phase and later fibrotic consequences. Vascular manifestations, particularly, large-vessel involvement in IgG4-RD, are well described. However, important IgG4-related effects on medium-sized arteries and the pericardium are less well recognized. These less frequently reported cardiovascular effects of IgG4-RD include coronary artery stenosis, pericardial disease, cardiac masses, and valvular heart disease. Case summary: This case series focuses on three patients that demonstrate the cardiovascular effects of IgG4-RD and the pitfalls and importance of early diagnosis. Cases 1 and 2 presented with cardiac manifestations prior to more typical organ systems being affected which led to a delay in diagnosis. Case 1 presented with an acute myocardial infarction secondary to IgG4-RD of the coronary arteries and Case 2 presented with pericarditis which progressed to pericardial constriction due to IgG4-RD. Case 3 already had a diagnosis of IgG4-RD from a prior renal biopsy which raised the index of suspicion that his pericardial disease and thoracic mass were also related to IgG4-RD. Discussion: Cardiac manifestations of IgG4-RD remain under-recognized and include coronary artery and pericardial disease. These manifestations often precede more typical manifestations in other organ systems. Recognizing cardiac manifestations of IgG4-RD on cardiac imaging can raise clinical suspicion and act as a catalyst to ascertain a confirmatory diagnosis. Early diagnosis and treatment are crucial to prevent potentially fatal outcomes and irreversible fibrosis.

Incidentally identified coronary artery calcium on non-contrast CT scan of the chest predicts major adverse cardiac events among hospital inpatients.

BACKGROUND: Coronary artery calcium (CAC) identified on non-gated CT scan of the chest is predictive of major adverse cardiac events (MACE) in multiple studies with guidelines therefore recommending the routine reporting of incidental CAC. These studies have been limited however to the outpatient setting. We aimed to determine the prognostic utility of incidentally identified CAC on CT scan of the chest among hospital inpatients. METHODS AND RESULTS: Consecutive patients (n=740) referred for inpatient non-contrast CT scan of the chest at a tertiary referral hospital (January 2011 to March 2017) were included (n=280) if they had no known history of coronary artery disease, active malignancy or died within 30 days of admission. Scans were assessed for the presence of CAC by visual assessment and quantified by Agatston scoring. Median age was 69 years (IQR: 54-82) and 51% were male with a median CAC score of 7 (IQR 0-205). MACE occurred in 140 (50%) patients at 3.5 years median follow-up including 98 deaths. Half of all events occurred within 18 months. Visible CAC was associated with increased MACE (HR) 6.0 (95% CI: 3.7 to 9.7) compared with patients with no visible CAC. This finding persisted after adjusting for cardiovascular risk factors HR 2.4 (95% CI: 1.3 to 4.3) and with both absolute CAC score and CAC score ≥50th percentile. CONCLUSION: Incidental CAC identified on CT scan of the chest among hospital inpatients provides prognostic information that is independent of cardiovascular risk factors. These patients may benefit from aggressive risk factor modification given the high event rate in the short term.

Chronic occlusion of the thoracic aorta: a novel cause of pleuropericardial effusions and pancytopenia.

A 57-year-old man had presented with a 6-month history of worsening dyspnea, renal failure, hypertension, pancytopenia, and a continuous machinery murmur. Imaging studies revealed pleuropericardial effusions that recurred despite aspiration and suprarenal mid-thoracic aortic occlusion (AO) with extensive collateral vessels to the chest wall, rectus sheath, and diaphragm. A right axillofemoral bypass transformed his clinical course. The murmurs, renal failure, pleuropericardial drainage, and pancytopenia resolved, and his hypertension had markedly improved. The association of chronic AO with pleuropericardial effusions without peripheral edema or ascites was most likely due to increased supradiaphragmatic interstitial pressure, and the bone marrow hypoperfusion likely explains the pancytopenia. In addition to posing diagnostic challenges, chronic AO reveals unique insights into the pathogenesis of pleuropericardial effusions and pancytopenia.

Survival outcomes for surgical resection versus CT-guided percutaneous ablation for stage I non-small cell lung cancer (NSCLC): a systematic review and meta-analysis.

OBJECTIVE: Multiple cohort studies have compared surgical resection with CT-guided percutaneous ablation for patients with stage 1 non-small cell lung cancer (NSCLC); however, the results have been heterogeneous. This systematic review and meta-analysis aims to compare surgery with ablation for stage 1 NSCLC. METHOD: A search of five databases was performed from inception to 5 July 2020. Studies were included if overall survival (OS), cancer-specific survival (CSS), and/or disease-free survival (DFS) were compared between patients treated with surgical resection versus ablation (radiofrequency ablation (RFA) or microwave ablation (MWA)) for stage 1 NSCLC. Pooled odds ratios (OR) were calculated. RESULTS: A total of eight studies were included (total 792 patients: 460 resection and 332 ablation). There were no significant differences in 1- to 5-year OS or CSS between surgery versus ablation. There were significantly better 1- and 2-year DFS for surgery over ablation (OR 2.22, 95% CI 1.14-4.34; OR 2.60, 95% CI 1.21-5.57 respectively), but not 3- to 5-year DFS. Subgroup analysis demonstrated no significant OS difference between lobectomy and MWA, but there were significantly better 1- and 2-year OS with sublobar resection (wedge resection or segmentectomy) versus RFA (OR 2.85, 95% CI 1.33-6.10; OR 4.54, 95% CI 2.51-8.21, respectively). In the two studies which only included patients with stage 1A NSCLC, pooled outcomes demonstrated no significant differences in 1- to 3-year OS or DFS between surgery versus ablation. CONCLUSION: Surgical resection of stage 1 NSCLC remains the optimal choice. However, for non-surgical patients with stage 1A, ablation offers promising DFS, CSS, and OS. Future prospective randomized controlled trials are warranted. KEY POINTS: • Surgical resection of stage 1 NSCLC remains the optimal choice. • In patients with stage 1A NSCLC who are not surgical candidates, CT-guided microwave or radiofrequency ablation may be an alternative which offers promising disease-free survival and overall survival.

Pneumothorax rates in CT-Guided lung biopsies: a comprehensive systematic review and meta-analysis of risk factors.

OBJECTIVE: This systematic review and meta-analysis investigated risk factors for pneumothorax following CT-guided percutaneous transthoracic lung biopsy. METHODS: A systematic search of nine literature databases between inception to September 2019 for eligible studies was performed. RESULTS: 36 articles were included with 23,104 patients. The overall pooled incidence for pneumothorax was 25.9% and chest drain insertion was 6.9%. Pneumothorax risk was significantly reduced in the lateral decubitus position where the biopsied lung was dependent compared to a prone or supine position [odds ratio (OR):3.15]. In contrast, pneumothorax rates were significantly increased in the lateral decubitus position where the biopsied lung was non-dependent compared to supine (OR:2.28) or prone position (OR:3.20). Other risk factors for pneumothorax included puncture site up compared to down through a purpose-built biopsy window in the CT table (OR:4.79), larger calibre guide/needles (≤18G vs >18G: OR 1.55), fissure crossed (OR:3.75), bulla crossed (OR:6.13), multiple pleural punctures (>1 vs 1: OR:2.43), multiple non-coaxial tissue sample (>1 vs 1: OR 1.99), emphysematous lungs (OR:3.33), smaller lesions (<4 cm vs 4 cm: OR:2.09), lesions without pleural contact (OR:1.73) and deeper lesions (≥3 cm vs <3cm: OR:2.38). CONCLUSION: This meta-analysis quantifies factors that alter pneumothorax rates, particularly with patient positioning, when planning and performing a CT-guided lung biopsy to reduce pneumothorax rates. ADVANCES IN KNOWLEDGE: Positioning patients in lateral decubitus with the biopsied lung dependent, puncture site down with a biopsy window in the CT table, using smaller calibre needles and using coaxial technique if multiple samples are needed are associated with a reduced incidence of pneumothorax.

Fistulae involving the appendix: a systematic review of the literature.

BACKGROUND: The appendix has a unique place in surgical history. Although the first ever appendicectomy involved a fistula to the skin, fistulae involving the appendix remain uncommon and can lead to unique surgical considerations. METHODS: A systematic review of the literature was performed for case reports of appendiceal fistulae. We excluded cases in which the patient had a history of appendicectomy. Cases were categorized by site and aetiology, with information regarding relative frequency and demographics obtained. RESULTS: A total of 301 case reports of fistula involving the appendix were found. The most common sites of these fistulae were to the bladder (148 cases), skin (40 cases), vasculature (19 cases), umbilicus (16 cases) and to the gastrointestinal tract. The most common aetiology in sub-analysis was appendicitis alone (150 cases), with less common causes including appendiceal adenocarcinoma (32 cases) and congenital abnormalities (18 cases). There were significantly more appendiceal fistulae in males than in females, with a ratio of 1.7:1. In patients with appendiceal adenocarcinoma as a cause for fistula, there were significantly more females than males with a ratio of 2.3:1. CONCLUSION: In conducting a systematic review of case reports of fistulae involving the appendix, we identified 301 unique case reports, with a range of different sites and aetiologies.

Post-Biopsy Manoeuvres to Reduce Pneumothorax Incidence in CT-Guided Transthoracic Lung Biopsies: A Systematic Review and Meta-analysis.

This systematic review and meta-analysis investigated post-biopsy manoeuvres to reduce pneumothorax following computed tomography-guided percutaneous transthoracic lung biopsy. Twenty-one articles were included with 7080 patients. Chest drain insertion rates were significantly reduced by ninefold with the normal saline tract sealant compared to controls (OR 0.11, 95% CI 0.02-0.48), threefold with the rapid rollover manoeuvre to puncture site down (OR 0.34, 95% CI 0.18-0.63), threefold with the tract plug (OR 0.33, 95% CI 0.22-0.48) and threefold with the blood patch (OR 0.39, 95% CI 0.26-0.58). The absolute chest drain insertion rates were the lowest in the normal saline tract sealant (0.8% vs 7.3% for controls), rapid rollover (1.9% vs 5.2%), deep expiration and breath-hold on needle extraction (0.9% vs 1.8%) and standard rollover versus no rollover (2.6% vs 5.2%). These findings highlight post-biopsy manoeuvres which could help reduce pneumothorax and chest drain insertions following lung biopsies. LEVEL OF EVIDENCE: Level 1/no level of evidence, systematic review.