Computed Tomography-Derived Extracellular Volume Fraction and Splenic Size for Liver Fibrosis Staging.

OBJECTIVE: Extracellular volume fraction (fECV) and liver and spleen size have been correlated with liver fibrosis stages and cirrhosis. The purpose of the current study was to determine the predictive value of fECV alone and in conjunction with measurement of liver and spleen size for severity of liver fibrosis. METHODS: This was a retrospective study of 95 subjects (65 with liver biopsy and 30 controls). Spearman rank correlation coefficient was used to assess correlation between radiological markers and fibrosis stage. Receiver operating characteristic analysis was performed to assess the discriminative ability of radiological markers for significant (F2+) and advanced (F3+) fibrosis and cirrhosis (F4), by reporting the area under the curve (AUC). RESULTS: The cohort had a mean age of 51.4 ± 14.4 years, and 52 were female (55%). There were 36, 5, 6, 9, and 39 in fibrosis stages F0, F1, F2, F3, and F4, respectively. Spleen volume alone showed the highest correlation (r = 0.552, P < 0.001) and AUCs of 0.823, 0.807, and 0.785 for identification of significant and advanced fibrosis and cirrhosis, respectively. Adding fECV to spleen length improved AUCs (0.764, 0.745, and 0.717 to 0.812, 0.781, and 0.738, respectively) compared with splenic length alone. However, adding fECV to spleen volume did not improve the AUCs for significant or advanced fibrosis or cirrhosis. CONCLUSIONS: Spleen size (measured in length or volume) showed better correlation with liver fibrosis stages compared with fECV. The combination of fECV and spleen length had higher accuracy compared with fECV alone or spleen length alone.

Opportunistic screening for osteoporosis using routine clinical care computed tomography brain studies.

OBJECTIVE: Osteoporosis and falls are both prevalent in the elderly, and CT brain (CTB) is frequently performed post head-strike. We aim to validate the relationship between frontal bone density (Hounsfield unit) from routine CTB and bone mineral density from dual-energy X-ray absorptiometry (DEXA) scan for opportunistic osteoporosis screening. MATERIALS AND METHODS: Patients who had a non-contrast CTB followed by a DEXA scan in the subsequent year were included in this multi-center retrospective study. The relationship between frontal bone density on CT and femoral neck T-score on DEXA was examined using ANOVA, Pearson's correlation, and receiver operating curve (ROC) analysis. Sensitivity, specificity, negative and positive predictive values, and area under the curve (AUC) were calculated. RESULTS: Three hundred twenty-six patients (205 females and 121 males) were analyzed. ANOVA analysis showed that frontal bone density was lower in patients with DEXA-defined osteoporosis (p < 0.001), while Pearson's correlation analysis demonstrated a fair correlation with femoral neck T-score (r = 0.3, p < 0.001). On subgroup analysis, these were true in females but not in males. On ROC analysis, frontal bone density weakly predicted osteoporosis (AUC 0.6, 95% CI 0.5-0.7) with no optimal threshold identified. HU < 610 was highly specific (87.5%) but poorly sensitive (18.9%). HU > 1200 in females had a strong negative predictive value for osteoporosis (92.6%, 95% CI 87.1-98.1%). CONCLUSION: Frontal bone density from routine CTB is significantly different between females with and without osteoporosis, but not between males. However, frontal bone density was a weak predictor for DEXA-defined osteoporosis. Further research is required to determine the role of CTB in opportunistic osteoporosis screening.

Higher Anti-tumor Necrosis Factor-α Levels Correlate With Improved Radiologic Outcomes in Crohn's Perianal Fistulas.

BACKGROUND & AIMS: Higher anti-tumor necrosis factor-α (TNF) drug levels are associated with improved clinical healing of Crohn's perianal fistulas. It is unclear whether this leads to improved healing on radiologic assessment. We aimed to evaluate the association between anti-TNF drug levels and radiologic outcomes in perianal fistulising Crohn's disease. METHODS: A cross-sectional retrospective multicenter study was undertaken. Patients with perianal fistulising Crohn's disease on maintenance infliximab or adalimumab, with drug levels within 6 months of perianal magnetic resonance imaging were included. Patients receiving dose changes or fistula surgery between drug level and imaging were excluded. Radiologic disease activity was scored using the Van Assche Index, with an inflammatory subscore calculated using indices: T2-weighted imaging hyperintensity, collections >3 mm diameter, rectal wall involvement. Primary endpoint was radiologic healing (inflammatory subscore ≤6). Secondary endpoint was radiologic remission (inflammatory subscore = 0). RESULTS: Of 193 patients (infliximab, n = 117; adalimumab, n = 76), patients with radiologic healing had higher median drug levels compared with those with active disease (infliximab 6.0 vs 3.9 µg/mL; adalimumab 9.1 vs 6.2 µg/mL; both P < .05). Patients with radiologic remission also had higher median drug levels compared with those with active disease (infliximab 7.4 vs 3.9 µg/mL; P < .05; adalimumab 9.8 vs 6.2 µg/mL; P = .07). There was a significant incremental reduction in median inflammatory subscores with higher anti-TNF drug level tertiles. CONCLUSIONS: Higher anti-TNF drug levels were associated with improved radiologic outcomes on magnetic resonance imaging in perianal fistulising Crohn's disease, with an incremental improvement at higher drug level tertiles for both infliximab and adalimumab.

Application of Thyroid Imaging Reporting and Data System (TIRADS) guidelines to thyroid nodules with cytopathological correlation and impact on healthcare costs.

AIMS: To assess the application of American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) guidelines and the potential reduction of unnecessary fine-needle aspirate (FNA) and cost savings through examination of cytopathological correlation. METHODS: All ultrasound-guided thyroid FNA performed between December 2017 and July 2019 at our institution were included in this study. Prior to performing each FNA, the nodules were scored according to ACR-TIRADS criteria with subsequent cytology scored according to Bethesda criteria. FNA request forms and preceding diagnostic ultrasound reports were analysed for clinical rationale behind each FNA. Collected data were applied to ACR-TIRADS, American Thyroid Association (ATA) and Korean TIRADS (K-TIRADS) criteria. Rate of reduction of unnecessary thyroid FNA and associated costs were subsequently calculated. RESULTS: A total of 125 patients and 146 nodules were evaluated. A malignancy rate of 7.5% was obtained. Sensitivity and specificity for detection of malignancy were 75% and 41% for ACR-TIRADS, 91% and 26% for ATA and 92% and 19% for K-TIRADS. Reduction in the rate of unnecessary FNA was most superior for ACR-TIRADS at 54.8%. Based on Australian Medicare Benefits Schedule item codes, a total of $18 452.70 might have been saved over the study period had ACR-TIRADS guidelines been uniformly followed. CONCLUSIONS: This study highlights the strengths and limitations of guidelines in the investigative pathway of thyroid nodules, including superiority of ACR-TIRADS in reducing the rate of unnecessary FNA. Continued education is needed towards application of guidelines among radiologists and referring clinicians, given the potential to reduce unnecessary FNA and achieve economic savings.

Impact of Image Reconstruction Parameters on Abdominal Aortic Calcification Measurement Using Abdominal Computed Tomography.

BACKGROUND AND AIMS: Abdominal aortic calcification (AAC) is correlated with cardiovascular outcomes independent of traditional risk factors. Quantification of AAC on computed tomography (CT) has not been standardized. Reconstruction parameters have been shown to impact coronary calcium scores. The aim of our study was to assess the impact of abdominal CT reconstruction parameters, slice thickness (ST), and display field of view (DFOV) on AAC quantitative scoring on abdominal CT examinations. METHODS: We retrospectively measured AAC on noncontrast CT of 46 patients (mean age, 64.1 years; 35 males) using 5 different reconstruction protocols with a range of ST and DFOV: protocol A, 2.5 mm ST, 35 cm DFOV; protocol B, 2.5 mm ST, 50 cm DFOV; protocol C, 2.5 mm ST, 25 cm DFOV; protocol D, 5 mm ST, 35 cm DFOV; and protocol E: 0.625 mm ST, 35 cm DFOV. The AAC scores from each protocol were compared using concordance correlation coefficient and Bland-Altman agreement analyses. RESULTS: The AAC mean (SD) scores for each protocol were as follows: A, 2022 (2418); B, 2022 (2412); C, 1939 (2310); D, 2220 (2695); and E, 1862 (2234). The AAC mean score differences between protocols and reference protocol A were -0.47, 82.01, -198.94, and 160 for protocols B, C, D, and E, respectively, with differences between protocols C to E statistically significantly different (P < 0.05). The different protocols showed overall excellent correlation (concordance correlation coefficient, >0.9) between AAC scores. CONCLUSIONS: Slice thickness and DFOV can impact AAC score measurement. A description of reconstruction parameters is important to allow comparisons across different cohorts.

Bone Marrow Adipose Tissue Quantification by Imaging.

PURPOSE OF REVIEW: The significance and roles of marrow adipose tissue (MAT) are increasingly known, and it is no more considered a passive fat storage but a tissue with significant paracrine and endocrine activities that can cause lipotoxicity and inflammation. RECENT FINDINGS: Changes in the MAT volume and fatty acid composition appear to drive bone and hematopoietic marrow deterioration, and studying it may open new horizons to predict bone fragility and anemia development. MAT has the potential to negatively impact bone volume and strength through several mechanisms that are partially described by inflammaging and lipotoxicity terminology. Evidence indicates paramount importance of MAT in age-associated decline of bone and red marrow structure and function. Currently, MAT measurement is being tested and validated by several techniques. However, purpose-specific adaptation of existing imaging technologies and, more importantly, development of new modalities to quantitatively measure MAT are yet to be done.

Accuracy of wrist fracture detection on radiographs by artificial intelligence compared to human clinicians. A systematic review and meta-analysis.

PURPOSE: The aim of the study is to perform a systematic review and meta-analysis comparing the diagnostic performance of artificial intelligence (AI) and human readers in the detection of wrist fractures. METHOD: This study conducted a systematic review following PRISMA guidelines. Medline and Embase databases were searched for relevant articles published up to August 14, 2023. All included studies reported the diagnostic performance of AI to detect wrist fractures, with or without comparison to human readers. A meta-analysis was performed to calculate the pooled sensitivity and specificity of AI and human experts in detecting distal radius, and scaphoid fractures respectively. RESULTS: Of 213 identified records, 20 studies were included after abstract screening and full-text review. Nine articles examined distal radius fractures, while eight studies examined scaphoid fractures. One study included distal radius and scaphoid fractures, and two studies examined paediatric distal radius fractures. The pooled sensitivity and specificity for AI in detecting distal radius fractures were 0.92 (95% CI 0.88-0.95) and 0.89 (0.84-0.92), respectively. The corresponding values for human readers were 0.95 (0.91-0.97) and 0.94 (0.91-0.96). For scaphoid fractures, pooled sensitivity and specificity for AI were 0.85 (0.73-0.92) and 0.83 (0.76-0.89), while human experts exhibited 0.71 (0.66-0.76) and 0.93 (0.90-0.95), respectively. CONCLUSION: The results indicate comparable diagnostic accuracy between AI and human readers, especially for distal radius fractures. For the detection of scaphoid fractures, the human readers were similarly sensitive but more specific. These findings underscore the potential of AI to enhance fracture detection accuracy and improve clinical workflow, rather than to replace human intelligence.

The identification of an optimal body size parameter to adjust skeletal muscle area on chest CT in COVID-19 patients.

Objectives: The most efficient way to adjust skeletal muscle area (SMA) derived from chest CT to body size remains unclear. We hypothesized that vertebral body area (VBA) measurement would allow such efficient adjustment. Methods: We conducted a retrospective observational study of chest CT imaging in a cohort of critically ill COVID-19 patients. We measured paravertebral SMA at T5 level and T5 vertebral body anteroposterior length, width, and area. We used linear regression and multivariable modelling to assess the association of VBA with SMA. Results: In 48 COVID-19 patients in ICU, T5 VBA could be easily derived from simple width and anteroposterior length linear measurements. T5 VBA (measured manually or estimated from width and length) performed similarly to height (R2 of 0.22) as an adjustment variable for SMA, with R2 of 0.23 and 0.22, respectively. Gender had the strongest correlation with SMA (R2 = 0.28). Adding height or age to a model using gender and VBA did not improve correlation. Conclusions: Gender and estimated VBA from simple linear measurements at T5 level on CT images can be utilized for adjustment of SMA without the need for height. Validation of these findings in larger cohorts of critically ill patients is now needed.

The impact of hepatic and splenic volumetric assessment in imaging for chronic liver disease: a narrative review.

Chronic liver disease is responsible for significant morbidity and mortality worldwide. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) can fully visualise the liver and adjacent structures in the upper abdomen providing a reproducible assessment of the liver and biliary system and can detect features of portal hypertension. Subjective interpretation of CT and MRI in the assessment of liver parenchyma for early and advanced stages of fibrosis (pre-cirrhosis), as well as severity of portal hypertension, is limited. Quantitative and reproducible measurements of hepatic and splenic volumes have been shown to correlate with fibrosis staging, clinical outcomes, and mortality. In this review, we will explore the role of volumetric measurements in relation to diagnosis, assessment of severity and prediction of outcomes in chronic liver disease patients. We conclude that volumetric analysis of the liver and spleen can provide important information in such patients, has the potential to stratify patients' stage of hepatic fibrosis and disease severity, and can provide critical prognostic information. CRITICAL RELEVANCE STATEMENT: This review highlights the role of volumetric measurements of the liver and spleen using CT and MRI in relation to diagnosis, assessment of severity, and prediction of outcomes in chronic liver disease patients. KEY POINTS: Volumetry of the liver and spleen using CT and MRI correlates with hepatic fibrosis stages and cirrhosis. Volumetric measurements correlate with chronic liver disease outcomes. Fully automated methods for volumetry are required for implementation into routine clinical practice.

Assessing quality of magnetic resonance enterography and its impact on disease assessment of ileal Crohn's disease.

BACKGROUND/AIMS: Assessment of quality of magnetic resonance enterography (MRE) in small bowel Crohn's disease (CD) activity evaluation has received little attention. We assessed the impact of bowel distention and motion artifact on MRE activity indices in ileal CD. METHODS: A cohort of patients who underwent contemporaneous MRE and colonoscopy for ileal CD assessment between 2014 and 2021 at 2 centers were audited. An abdominal radiologist blinded to clinical data reviewed each MRE, graded bowel distention and motion artifact upon a pre-specified 3-point scale and calculated the original magnetic resonance index of activity (MaRIA) and simplified MaRIA (sMaRIA), London index and CD MRE index (CDMI). Ileal endoscopic activity was graded via the Simplified Endoscopy Score for CD (SES-CD). The performance of MRE indices in discriminating active disease (SES-CD ≥3) stratified by MRE quality was measured by receiver operator characteristic analyses. RESULTS: One hundred and thirty-seven patients had MRE and colonoscopy within a median of 16 days (range, 0-30 days) with 63 (46%) exhibiting active disease (SES-CD ≥3). Forty-four MREs (32%) were deemed low quality due to motion artifact and/or moderate to poor distention. Low-quality MREs demonstrated reduced discriminative performance between ileal SES-CD ≥3 and MRE indices (MaRIA 0.838 vs. 0.634, sMaRIA 0.834 vs. 0.527, CDMI 0.850 vs. 0.595, London 0.748 vs. 0.511, P<0.05 for all). Individually the presence of any motion artifact markedly impacted the discriminative performance (e.g., sMaRIA area under the curve 0.544 vs. 0.814, P<0.05). CONCLUSIONS: Image quality parameters can significantly impact MRE disease activity interpretation. Quality metrics should be reported, enabling cautious interpretation in lower-quality studies.

Statin, aspirin and metformin use and risk of hepatocellular carcinoma related outcomes following liver transplantation: A retrospective study.

BACKGROUND: Liver transplantation (LT) is a potentially curative therapy for patients with hepatocellular carcinoma (HCC). HCC-recurrence following LT is associated with reduced survival. There is increasing interest in chemoprophylaxis to improve HCC-related outcomes post-LT. AIM: To investigate whether there is any benefit for the use of drugs with proposed chemoprophylactic properties against HCC, and patient outcomes following LT. METHODS: This was a retrospective study of adult patients who received Deceased Donor LT for HCC from 2005-2022, from a single Australian centre. Drug use was defined as statin, aspirin or metformin therapy for ≥ 29 days, within 24 months post-LT. A cox proportional-hazards model with time-dependent covariates was used for survival analysis. Outcome measures were the composite-endpoint of HCC-recurrence and all-cause mortality, HCC-recurrence and HCC-related mortality. Sensitivity analysis was performed to account for immortality time bias and statin dosing. RESULTS: Three hundred and five patients were included in this study, with 253 (82.95%) males with a median age of 58.90 years. Aetiologies of liver disease were 150 (49.18%) hepatitis C, 73 (23.93%) hepatitis B (HBV) and 33 (10.82%) non-alcoholic fatty liver disease (NAFLD). 56 (18.36%) took statins, 51 (16.72%) aspirin and 50 (16.39%) metformin. During a median follow-up time of 59.90 months, 34 (11.15%) developed HCC-recurrence, 48 (15.74%) died, 17 (5.57%) from HCC-related mortality. Statin, aspirin or metformin use was not associated with statistically significant differences in the composite endpoint of HCC-recurrence or all-cause mortality [hazard ratio (HR): 1.16, 95%CI: 0.58-2.30; HR: 1.21, 95%CI: 0.28-5.27; HR: 0.61, 95%CI: 0.27-1.36], HCC-recurrence (HR: 0.52, 95%CI: 0.20-1.35; HR: 0.51, 95%CI: 0.14-1.93; HR 1.00, 95%CI: 0.37-2.72), or HCC-related mortality (HR: 0.32, 95%CI: 0.033-3.09; HR: 0.71, 95%CI: 0.14-3.73; HR: 1.57, 95%CI: 0.61-4.04) respectively. Statin dosing was not associated with statistically significant differences in HCC-related outcomes. CONCLUSION: Statin, metformin or aspirin use was not associated with improved HCC-related outcomes post-LT, in a largely historical cohort of Australian patients with a low proportion of NAFLD. Further prospective, multicentre studies are required to clarify any potential benefit of these drugs to improve HCC-related outcomes.

Height Estimation from Vertebral Parameters on Routine Computed Tomography in a Contemporary Elderly Australian Population: A Validation of Existing Regression Models.

The aim of this study is to compare previously published height estimation formulae in a contemporary Australian population using vertebral measurements readily available on abdominal CT. Retrospective analysis of patients undergoing a planning CT prior to transcatheter aortic valve implantation in a 12-month period was conducted; 96 participants were included in the analysis from a total of 137, with 41 excluded due to incomplete data. Seven vertebral measurements were taken from the CT images and height estimates were made for each participant using multiple regression equations from the published literature. Paired sample t-tests were used to compare actual height to estimated height. Many of the models failed to accurately predict patient height in this cohort, with only three equations for each sex resulting in a predicted height that was not statistically significantly different to actual height. The most accurate model in female participants was based on posterior sacral length and resulted in a mean difference between an actual and calculated height of 0.7 cm (±7.4) (p = 0.520). The most accurate model in male participants was based on anterior sacrococcygeal length and resulted in a mean difference of -0.6 ± 6.9 cm (p = 0.544). Height estimation formulae can be used to predict patient height from common vertebral parameters on readily available CT data. This is important for the calculation of anthropometric measures for a variety of uses in clinical medicine. However, more work is needed to generate accurate prediction models for specific populations.

Replacing Endoscopy with Magnetic Resonance Enterography for Mucosal Activity Assessment in Terminal Ileal Crohn's Disease: Are We There Yet?

Crohn's disease (CD) is a chronic immune mediated disorder that most commonly affects the small bowel and/or the large bowel. Treatment targets in CD include mucosal healing assessed via ileocolonoscopy and transmural healing assessed through cross-sectional imaging modalities such as magnetic resonance enterography (MRE). More recently, histological healing in CD has emerged as a treatment target, though it is made cumbersome given its reliance on frequent endoscopic examinations. With expert guidelines now recommending regular objective assessments as part of a treat-to-target approach, accurate non-invasive assessment will become increasingly critical. MRE has an established role in the assessment of small bowel CD, with growing data supportive of its ability in detecting disease activity at mucosal and histological levels. This could therefore potentially reduce the need for serial endoscopic assessment. Thus, this review will assess the capacity of individual MRE parameters and MRE indices for detecting mucosal and histological small bowel CD activity. Furthermore, challenging scenarios, such as CD activity detection in post-operative clinical scenarios and abnormal findings in the context of a normal ileocolonoscopy, will be explored.

Radiation exposure from radiological procedures in liver transplant candidates with hepatocellular carcinoma.

PURPOSE: Candidates for liver transplantation (LT) with hepatocellular carcinoma (HCC) undergo a large number of diagnostic and interventional radiology procedures. A significant proportion of such procedures involve ionizing radiation with increased lifetime risk of cancer. The objective of our study was to review LT candidates with HCC to quantify ionizing radiation doses from different radiology procedures performed at a single transplant center. METHOD: We retrospectively reviewed 179 adult patients with HCC (median age 58.6 years [IQR, 55-62]; 155 [86.6%] males) who were accepted for LT between April 2010 and Dec 2018. Radiology procedures and radiation doses were retrieved and the total and median radiation effective dose in millisieverts (mSv) were calculated for different procedures. Exposure to ionizing radiation was categorized based on previously reported thresholds. RESULTS: We assessed 9,986 radiology procedures for our cohort. Patients had a median effective dose prior to transplantation of 254 mSv (IQR, 130-421) with an annualized rate of 152 mSv (IQR, 92-266). Patient median dose increased to 316 mSv (IQR, 159-478) when including exposures post-LT within the study period. 85% of overall exposure was in the extremely high exposure category (>100 mSv). Interventional procedures represented 13% of procedures with substantial radiation and contributed to 45% of radiation exposure while abdominal CTs represented 39% of total procedures and contributed to 45% of radiation exposure. CONCLUSIONS: Patients with HCC considered for LT undergo radiology procedures with significant cumulative radiation exposure. Attempts to reduce radiation exposure are suggested by minimizing unnecessary procedures and utilizing ones without ionizing radiation. Improving interventional techniques to reduce radiation doses is needed without compromising treatment delivery.

Evaluation of techniques to improve a deep learning algorithm for the automatic detection of intracranial haemorrhage on CT head imaging.

BACKGROUND: Deep learning (DL) algorithms are playing an increasing role in automatic medical image analysis. PURPOSE: To evaluate the performance of a DL model for the automatic detection of intracranial haemorrhage and its subtypes on non-contrast CT (NCCT) head studies and to compare the effects of various preprocessing and model design implementations. METHODS: The DL algorithm was trained and externally validated on open-source, multi-centre retrospective data containing radiologist-annotated NCCT head studies. The training dataset was sourced from four research institutions across Canada, the USA and Brazil. The test dataset was sourced from a research centre in India. A convolutional neural network (CNN) was used, with its performance compared against similar models with additional implementations: (1) a recurrent neural network (RNN) attached to the CNN, (2) preprocessed CT image-windowed inputs and (3) preprocessed CT image-concatenated inputs. The area under the receiver operating characteristic curve (AUC-ROC) and microaveraged precision (mAP) score were used to evaluate and compare model performances. RESULTS: The training and test datasets contained 21,744 and 491 NCCT head studies, respectively, with 8,882 (40.8%) and 205 (41.8%) positive for intracranial haemorrhage. Implementation of preprocessing techniques and the CNN-RNN framework increased mAP from 0.77 to 0.93 and increased AUC-ROC [95% confidence intervals] from 0.854 [0.816-0.889] to 0.966 [0.951-0.980] (p-value = 3.91 × 10-12). CONCLUSIONS: The deep learning model accurately detected intracranial haemorrhage and improved in performance following specific implementation techniques, demonstrating clinical potential as a decision support tool and an automated system to improve radiologist workflow efficiency. KEY POINTS: • The deep learning model detected intracranial haemorrhages on computed tomography with high accuracy. • Image preprocessing, such as windowing, plays a large role in improving deep learning model performance. • Implementations which enable an analysis of interslice dependencies can improve deep learning model performance. • Visual saliency maps can facilitate explainable artificial intelligence systems. • Deep learning within a triage system may expedite earlier intracranial haemorrhage detection.

Evaluating treatment response following locoregional therapy for hepatocellular carcinoma: A review of the available serological and radiological tools for assessment.

Hepatocellular carcinoma (HCC) is an aggressive primary malignancy of the liver and is the third most common cause of cancer-related global mortality. There has been a steady increase in treatment options for HCC in recent years, including innovations in both curative and non-curative therapies. These advances have brought new challenges and necessary improvements in strategies of disease monitoring, to allow early detection of HCC recurrence. Current serological and radiological strategies for post-treatment monitoring and prognostication and their limitations will be discussed and evaluated in this review.