Are T2WI PI-RADS sub-scores of transition zone prostate lesions biased by DWI information? A multi-reader, single-center study

PURPOSE

According to PI-RADS v2.1, T2-weighted imaging (T2WI) is the dominant sequence for transition zone (TZ) lesions. This study aimed to assess, whether diffusion-weighted imaging (DWI) information influences the assignment of T2WI scores.

METHOD

Out of 283 prostate MRI examinations with correlated biopsy results, fourty-four patients were selected retrospectively: first, 22 patients with a TZ lesion with T2WI and DWI scores ≥ 4, to represent lesions with unequivocal suspicion on T2WI and DWI. Second, 22 additional patients with TZ lesions of similar T2WI appearance but with corresponding DWI score ≤ 3 were added as control. Four residents and one board-certified radiologist each performed two assessments of the included patients: First, only T2WI was available (T2-only read); second, both T2WI and DWI sequences were available (biparametric read). Lesion scores were assessed using Wilcoxon signed-rank test, inter-reader agreement using weighted kappa and Kendall's W statistics, and sensitivity/specificity using McNemar test.

RESULTS

The T2WI scores were significantly different between the T2-only and biparametric read for 3 out of 4 residents (p ≤ 0.049) but not for the radiologist. The overall PI-RADS scores derived from the two reading sessions differed considerably for 35/220 cases (all readers pooled). Inter-reader agreement was fair for the T2WI and overall PI-RADS scores (mean kappa 0.27-0.30) and moderate for the DWI scores (mean kappa 0.43).

CONCLUSIONS

For inexperienced readers, assessment of T2WI is variable and potentially biased by availability of DWI information, which can lead to changes of overall PI-RADS score and consequently clinical management. Assessment of T2WI should be performed before reviewing DWI to ensure non-biased interpretation of TZ lesions in the dominant sequence.

First application of dynamic oxygen-17 magnetic resonance imaging at 7 Tesla in a patient with early subacute stroke

Dynamic oxygen-17 (¹⁷O) magnetic resonance imaging (MRI) is an imaging method that enables a direct and non-invasive assessment of cerebral oxygen metabolism and thus potentially the distinction between viable and non-viable tissue employing a three-phase inhalation experiment. The purpose of this investigation was the first application of dynamic ¹⁷O MRI at 7 Tesla (T) in a patient with stroke. In this proof-of-concept experiment, dynamic ¹⁷O MRI was applied during ¹⁷O inhalation in a patient with early subacute stroke. The analysis of the relative ¹⁷O water (H₂¹⁷O) signal for the affected stroke region compared to the healthy contralateral side revealed no significant difference. However, the technical feasibility of ¹⁷O MRI has been demonstrated paving the way for future investigations in neurovascular diseases.

[Li-Fraumeni syndrome]

BACKGROUND

The autosomal dominant inherited Li-Fraumeni syndrome (LFS) increases the lifetime risk of developing a malignancy to almost 100%. Although breast cancer, central nervous system (CNS) tumors and sarcomas are particularly common, tumors can ultimately occur almost anywhere in the body. As causal therapy is not available, the primary focus for improving the prognosis is early cancer detection. To this end, current cancer surveillance recommendations include a series of examinations including regular imaging beginning at birth.

CHALLENGES IN IMAGING IN LFS

Due to the wide range of tumor entities that can occur in individuals affected by LFS, a sensitive detection requires imaging of various tissue contrasts; however, because life-long screening is potentially initiated at a young age, this requirement for comprehensiveness must be balanced against the presumed high psychological burden associated with frequent or invasive examinations. As radiation exposure may lead to an increased (secondary) tumor risk, computed tomography (CT) and X‑ray examinations should be avoided as far as possible.

CURRENT STATUS AND PERSPECTIVES

Because annual whole-body magnetic resonance imaging (MRI) has no radiation exposure and yet a high sensitivity for many tumors, it forms the basis of the recommended imaging; however, due to the rarity of the syndrome, expertise is sometimes lacking and whole-body MRI examinations are performed heterogeneously and sometimes with limited diagnostic quality. Optimization and standardization of MRI protocols should therefore be pursued. In addition, the need for an intravenously administered contrast agent has not been conclusively clarified despite its high relevance.

Health Behavior and Cancer Prevention among Adults with Li-Fraumeni Syndrome and Relatives in Germany-A Cohort Description

Li-Fraumeni-syndrome (LFS) is a rare, highly penetrant cancer predisposition syndrome (CPS) caused by pathogenic variants (PVs) in TP53. Physical activity (PA) and a Mediterranean diet lead to cancer reduction or survival benefits and increased quality of life (QoL), but this is yet unstudied among LFS. TP53 PV carriers (PVC) and their relatives were questioned on dietary patterns (Mediterranean Diet Adherence Screener), PA (Freiburg Questionnaire), QoL (Short-form-Health-Survey-12), smoking, alcohol consumption and perception of cancer risk in a German bi-centric study from March 2020-June 2021. The study enrolled 70 PVC and 43 relatives. Women compared to men (6.49 vs. 5.38, p = 0.005) and PVC to relatives (6.59 vs. 5.51; p = 0.006) showed a healthier diet, associated with participation in surveillance (p = 0.04) and education (diet p = 0.02 smoking p = 0.0003). Women smoked less (2.91 vs. 5.91 packyears; p = 0.03), psychological well-being was higher among men (SF-12: males 48.06 vs. females 41.94; p = 0.004). PVC rated their own cancer risk statistically higher than relatives (72% vs. 38%, p < 0.001) however, cancer risk of the general population was rated lower (38% vs. 70%, p < 0.001). A relative's cancer-related death increased the estimated personal cancer risk (p = 0.01). The possibilities of reducing cancer through self-determined health behavior among PVC and relatives has not yet been exhausted. Educating families with a CPS on cancer-preventive behavior requires further investigation with regard to acceptance and real-life implementation.

Pseudoprospective Paraclinical Interaction of Radiology Residents With a Deep Learning System for Prostate Cancer Detection: Experience, Performance, and Identification of the Need for Intermittent Recalibration

OBJECTIVES

The aim of this study was to estimate the prospective utility of a previously retrospectively validated convolutional neural network (CNN) for prostate cancer (PC) detection on prostate magnetic resonance imaging (MRI).

MATERIALS AND METHODS

The biparametric (T2-weighted and diffusion-weighted) portion of clinical multiparametric prostate MRI from consecutive men included between November 2019 and September 2020 was fully automatically and individually analyzed by a CNN briefly after image acquisition (pseudoprospective design). Radiology residents performed 2 research Prostate Imaging Reporting and Data System (PI-RADS) assessments of the multiparametric dataset independent from clinical reporting (paraclinical design) before and after review of the CNN results and completed a survey. Presence of clinically significant PC was determined by the presence of an International Society of Urological Pathology grade 2 or higher PC on combined targeted and extended systematic transperineal MRI/transrectal ultrasound fusion biopsy. Sensitivities and specificities on a patient and prostate sextant basis were compared using the McNemar test and compared with the receiver operating characteristic (ROC) curve of CNN. Survey results were summarized as absolute counts and percentages.

RESULTS

A total of 201 men were included. The CNN achieved an ROC area under the curve of 0.77 on a patient basis. Using PI-RADS ≥3-emulating probability threshold (c3), CNN had a patient-based sensitivity of 81.8% and specificity of 54.8%, not statistically different from the current clinical routine PI-RADS ≥4 assessment at 90.9% and 54.8%, respectively ( P = 0.30/ P = 1.0). In general, residents achieved similar sensitivity and specificity before and after CNN review. On a prostate sextant basis, clinical assessment possessed the highest ROC area under the curve of 0.82, higher than CNN (AUC = 0.76, P = 0.21) and significantly higher than resident performance before and after CNN review (AUC = 0.76 / 0.76, P ≤ 0.03). The resident survey indicated CNN to be helpful and clinically useful.

CONCLUSIONS

Pseudoprospective paraclinical integration of fully automated CNN-based detection of suspicious lesions on prostate multiparametric MRI was demonstrated and showed good acceptance among residents, whereas no significant improvement in resident performance was found. General CNN performance was preserved despite an observed shift in CNN calibration, identifying the requirement for continuous quality control and recalibration.

Genotype-phenotype associations within the Li-Fraumeni spectrum: a report from the German Registry

Li-Fraumeni syndrome (LFS) is a cancer predisposition syndrome caused by pathogenic TP53 variants. The condition represents one of the most relevant genetic causes of cancer in children and adults due to its frequency and high cancer risk. The term Li-Fraumeni spectrum reflects the evolving phenotypic variability of the condition. Within this spectrum, patients who meet specific LFS criteria are diagnosed with LFS, while patients who do not meet these criteria are diagnosed with attenuated LFS. To explore genotype-phenotype correlations we analyzed 141 individuals from 94 families with pathogenic TP53 variants registered in the German Cancer Predisposition Syndrome Registry. Twenty-one (22%) families had attenuated LFS and 73 (78%) families met the criteria of LFS. NULL variants occurred in 32 (44%) families with LFS and in two (9.5%) families with attenuated LFS (P value < 0.01). Kato partially functional variants were present in 10 out of 53 (19%) families without childhood cancer except adrenocortical carcinoma (ACC) versus 0 out of 41 families with childhood cancer other than ACC alone (P value < 0.01). Our study suggests genotype-phenotype correlations encouraging further analyses.

Bioimpedance-based identification of malnutrition using fuzzy logic

Protein-energy malnutrition reduces the quality of life, lengthens the time in hospital and dramatically increases mortality. Currently there is no simple and objective method available for assessing nutritional status and identifying malnutrition. The aim of this work is to develop a novel assistance system that supports the physician in the assessment of the nutritional status. Therefore, three subject groups were investigated: the first group consisted of 688 healthy subjects. Two additional groups consisted of 707 patients: 94 patients with primary diseases that are known to cause malnutrition, and 613 patients from a hospital admission screening. In all subjects bioimpedance spectroscopy measurements were performed, and the body composition was calculated. Additionally, in all patients the nutritional status was assessed by the subjective global assessment score. These data are used for the development and validation of the assistance system. The basic idea of the system is that nutritional status is reflected by body composition. Hence, features of the nutritional status, based on the body composition, are determined and compared with reference ranges, derived from healthy subjects' data. The differences are evaluated by a fuzzy logic system or a decision tree in order to identify malnourished patients. The novel assistance system allows the identification of malnourished patients, and it can be applied for screening and monitoring of the nutritional status of hospital patients.

Colorectal stenting

Intestinal stenting is a procedure that is rapidly coming into more widespread use. It is reported to be a safe and highly effective alternative in patients with unresectable intestinal obstruction. Recent reports show the value of this procedure in colorectal obstruction, as it is relatively safe and can avoid the need for high-risk emergency laparotomy and resection in two sessions. New stents can be inserted in a one-step procedure, with delivery through the scope during the initial diagnostic endoscopy. If examinations show that curative treatment is not possible, resection can be completely avoided, so that the initial stent already forms part of the palliative strategy. Although stents are expensive, the procedure appears to be cost-effective, since emergency surgery can be avoided in patients with acute bowel obstruction, and in those with advanced disease no resection of the colon is necessary.

Technical aspects of enteral nutrition

Advances in technical aspects of enteral feeding such as the manufacture of tubes from polyurethane or silicone have helped promote the science of enteral nutrition. Nasoenteral tubes have few complications, apart from a high unwanted extubation rate and some reluctance from patients because of cosmetic unacceptability. Needle jejunostomy has low morbidity but can only be placed at laparotomy. Percutaneous gastrotomy (in all its different guises) has been established as a low risk procedure and is the access route of choice for longterm enteral feeding, in particular for cancer, geriatric, and neurological patients.

A controlled trial of an expansile metal stent for palliation of esophageal obstruction due to inoperable cancer

BACKGROUND

Esophageal obstruction due to cancer can produce debilitating dysphagia. Rapid palliation is usually possible with endoscopic placement of a plastic esophageal prosthesis, but this device has a high rate of complications. A new alternative is a metal-mesh stent that collapses to 3 mm in diameter at placement but can then expand up to 16 mm.

METHODS

Patients with esophageal carcinoma (39 patients) or malignant extrinsic obstruction (3 patients) were randomly assigned to treatment with either a plastic prosthesis (16 mm in diameter) or an expansile metal-mesh stent. The patients were evaluated every six weeks until death. The degree of palliation was expressed as a dysphagia score and a Karnofsky performance score.

RESULTS

Complications were significantly less frequent with the metal stents than with the plastic prostheses (no complications vs. nine; P < 0.001). The dysphagia and Karnofsky scores improved significantly and to a similar degree in both treatment groups. The most common causes of recurrent dysphagia were migration of the plastic prostheses (five patients) and ingrowth or overgrowth of the metal stents by tumor (five patients). The rates of reintervention were similar in both treatment groups, as were the 30-day mortality rates. The period of hospitalization after placement of a prosthesis was significantly longer in the group given plastic prostheses than in the group given metal stents (mean +/- SE, 12.5 +/- 2.1 vs. 5.4 +/- 1.0 days; P = 0.005). Despite their higher initial cost, the metal stents were cost effective because of the absence of fatal complications and the decrease in the hospital stay.

CONCLUSIONS

Expansile metal stents are a safe and cost-effective alternative to conventional plastic endoprostheses in the treatment of esophageal obstruction due to inoperable cancer.

[Reactions of the liver to high caloric enteral feeding with formula diets]

We studied serum hepatic enzyme alterations in 36 patients receiving continuous enteral hyperalimentation. In 50% of the patients studied a marked increase in liver enzymes could be noticed. Elevations returned to normal either spontaneously during enteral feeding or after feeding was discontinued. In 7 patients, alkaline phosphatase decreased significantly 21 +/- 13 days after institution of tube feeding. The rise in liver enzyme values could not be accounted for by preexistent hepatobiliary affection, caloric load or composition of the formula diet. Further studies are needed to determine whether cyclic isocaloric enteral nutrition will minimize complications and hepatic enzyme changes after enteral nutrition.

[Chemotherapy and enteral nutrition in stomach cancer]

Malnutrition is a frequent problem in cancer patients. About 45% of them lose more than 10% of their original weight at the various stages of their disease. The importance of nutritional support was repeatedly pointed out. In our study, 10 patients with metastatic gastrointestinal cancer received a combination treatment of long-term tube feeding with elemental diets and chemotherapy. The initially low Karnofsky index improved significantly. The results of the chemotherapy are comparable to those of 9 international studies between 1976 and 1979, using a comparable therapeutic scheme in patients with initially higher Karnofsky index. Ingestion-dependent abdominal pain disappeared in responders and non-responders during the time of tube feeding.

[Possibilities for the use of formula diets for tumor patients]

Malnutrition is a frequent problem in cancer patients. Nearly 50% of all tumor patients lose more than 10% of their pre-illness weight during the various stages of their disease. Ingestion-dependent abdominal pain in patients with gastrointestinal tumor complications is a major problem among the causes which are under discussion. Elemental diet has a safe analgetic effect in these patients because of its quick and complete resorption in proximal parts oft the jejunum. Tube feeding with elemental diets can be provided fully ambulatory and leads to a significant increase in the quality of life of cancer patients. This was demonstrated in a group of 38 malnourished cancer patients. The effect of tube feeding combined with chemotherapy was investigated in a small group of 10 patients with low Karnofsky index. The outcome was compared to the results of 9 international chemotherapy studies using the same chemotherapeutic regime without artificial feeding.