MRI identifies biochemical alterations of intervertebral discs in patients with low back pain and radiculopathy

Key Points

• Molecular intervertebral disc damage was associated with LBP and radiculopathy.

• Patients with radiculopathy and LBP demonstrated a depletion of gagCEST values compared with healthy controls.

• GagCEST imaging may be a non-invasive tool for investigation of degeneration processes of lumbar intervertebral discs (IVDs). GagCEST imaging may be an imaging biomarker for biochemical IVD alterations.

How patient off-centering impacts organ dose and image noise in pediatric head and thoracoabdominal CT

Abstract

Objectives

To assess the impact of patient off-centering on organ dose and image noise for head and thoracoabdominal CT in a pediatric phantom.

Methods

An anthropomorphic phantom simulating a 5-year-old child was used. Semiconductor dosimeters were placed in various cranial and thoracoabdominal organs. Head and thoracoabdominal CT were performed using automatic tube current modulation (ATCM) and default bowtie filters. The phantom was imaged repeatedly at vertical table positions ranging from − 6 to + 6 cm from the 0-position. Tube current time products (TCTP), organ doses, and image noise were recorded. Scatter radiation was measured in the thyroid for head CT. The effect of ATCM and bowtie filters was assessed.

Results

Depending on patient position, organ doses differed up to 22% for the supratentorial brain, 34% for the infratentorial brain, 19% for the eyes, 28% for the lungs, 25% for the stomach, and 22% for the liver compared with those in the 0-position. The relation between position and dose was linear and mainly affected by the bowtie filter in head CT, while it was quadratic and affected by ATCM and bowtie filter in thoracoabdominal CT. It further depended on the relative position of each organ to the isocenter. An inverse relation was found between position and image noise. Scatter radiation was not significantly related to patient positioning (p = 0.21).

Conclusions

In pediatric CT, vertical patient positioning had a substantial impact on radiation dose with differences of up to 34%, depending on the body region and location of each individual organ.

Key Points

• Patient off-centering has a substantial impact on organ radiation dose and image noise in pediatric CT.

• Impact of patient off-centering on radiation dose and noise differs between head and thoracoabdominal CT.

• Differences are caused by both ATCM and bowtie filter in thoracoabdominal CT, but mainly by bowtie filter in head CT.

Temporal subtraction of computed tomography images improves detectability of bone metastases by radiology residents

Abstract

Objective

Temporal subtraction of CT (TS) images improves detection of newly developed bone metastases (BM). We sought to determine whether TS improves detection of BM by radiology residents as well.

Methods

We performed an observer study using a previously reported dataset, consisting of 60 oncology patients, each with previous and current CT images. TS images were calculated using in-house software. Four residents independently interpreted twice the 60 sets of CT images, without and with TS. They identified BM by marking suspicious lesions likely to be BM. Lesion-based sensitivity and number of false positives per patient were calculated. Figure-of-merit (FOM) was calculated. Detectability of BM, with and without TS, was compared between radiology residents and board-certified radiologists, as published previously.

Results

FOM of residents significantly improved by implementing TS (p value < 0.0001). Lesion-based sensitivity, false positives per patients, and FOM were 40.8%, 0.121, and 0.657, respectively, without TS, and 58.1%, 0.0958, and 0.796, respectively, with TS. These findings were comparable with the previously published values for board-certified radiologists without TS (58.0%, 0.19, and 0.758, respectively).

Conclusion

The detectability of BM by residents improved markedly by implementing TS and reached that of board-certified radiologists without TS.

Key Points

• Detectability of bone metastases on CT by residents improved significantly when using temporal subtraction of CT (TS).

• Detections by residents with TS and board-certified radiologists without TS were comparable.

• TS is useful for residents as it is for board-certified radiologists.

CT texture analysis in the differentiation of major renal cell carcinoma subtypes and correlation with Fuhrman grade

Abstract

Objective

CT texture analysis (CTTA) using filtration-histogram–based parameters has been associated with tumor biologic correlates such as glucose metabolism, hypoxia, and tumor angiogenesis. We investigated the utility of these parameters for differentiation of clear cell from papillary renal cancers and prediction of Fuhrman grade.

Methods

A retrospective study was performed by applying CTTA to pretreatment contrast-enhanced CT scans in 290 patients with 298 histopathologically confirmed renal cell cancers of clear cell and papillary types. The largest cross section of the tumor on portal venous phase axial CT was chosen to draw a region of interest. CTTA comprised of an initial filtration step to extract features of different sizes (fine, medium, coarse spatial scales) followed by texture quantification using histogram analysis.

Results

A significant increase in entropy with fine and medium spatial filters was demonstrated in clear cell RCC (p = 0.047 and 0.033, respectively). Area under the ROC curve of entropy at fine and medium spatial filters was 0.804 and 0.841, respectively. An increased entropy value at coarse filter correlated with high Fuhrman grade tumors (p = 0.01). The other texture parameters were not found to be useful.

Conclusion

Entropy, which is a quantitative measure of heterogeneity, is increased in clear cell renal cancers. High entropy is also associated with high-grade renal cancers. This parameter may be considered as a supplementary marker when determining aggressiveness of therapy.

Key points

• CT texture analysis is easy to perform on contrast-enhanced CT.

• CT texture analysis may help to separate different types of renal cancers.

• CT texture analysis may enhance individualized treatment of renal cancers.

Impact of sublingual nitroglycerin dosage on FFR CT assessment and coronary luminal volume–to–myocardial mass ratio

Abstract

Objectives

Fractional flow reserve computed tomography (FFR_CT) depends upon nitroglycerin (NTG) inducing maximal hyperemia. However, the impact of NTG dosages on FFR_CT analysis including coronary volume–to–mass ratio (V/M) is unknown.

Methods

Eighty patients with repeat coronary CT angiograms (CCTAs) with different sublingual spray NTG doses (0.4 mg and 0.8 mg) were retrospectively analyzed with 45 patients excluded. Patient and scan demographics, post-stenosis and nadir FFR_CT values, coronary volume, and coronary volume–to–mass ratio (V/M) were compared at initial CCTA (0.4 mg NTG) and follow-up CCTA (0.8 mg NTG). Differences were compared by Wilcoxon signed-rank test.

Results

Thirty-five patients were included (time between CCTAs, 3.9 ± 1.6 years). Segment involvement score was 2.4 ± 3.3 and 2.8 ± 3.4 at initial and repeat CCTA (0.4 and 0.8 mg NTG), respectively (p = 0.004). There was similar image quality (4.1 ± 0.7 vs 4.1 ± 0.8; p = 0.51). Nadir FFR_CT values did not differ in the left (0.4 mg, 0.80 ± 0.08 vs 0.8 mg, 0.80 ± 0.03; p = 0.66), right (0.4 mg, 0.90 ± 0.04 vs 0.8 mg, 0.90 ± 0.06; p = 0.25), or circumflex coronaries (0.4 mg, 0.87 ± 0.06 vs 0.8 mg, 0.88 ± 0.06; p = 0.34). Post-stenosis FFR_CT values did not differ (p = 0.65). Coronary volume increased with 0.8 mg of NTG (2639 ± 753 mm³ vs 2844.8 ± 827 mm³; p = 0.009) but V/M ratio did not (p = 0.20).

Conclusions

Use of 0.8 mg versus 0.4 mg of NTG in routine clinical CCTAs significantly increased coronary volume determined from FFR_CT analysis but did not alter FFR_CT or V/M. Further evaluation of repeat CCTAs in a more contemporaneous fashion using varied nitrate doses and disease severity is needed.

Key Points

• Fractional flow reserve from computed tomography (FFR_CT) is a noninvasive method for evaluating the coronary arteries and relies on nitroglycerin (NTG) to induce coronary vasodilation, but the impact of different NTG dosages is unknown.

• Retrospective analysis evaluated use of different NTG doses on FFR_CT.

• Increased NTG dose increased coronary luminal volume on FFR_CTanalysis, but did not change FFR_CTvalues.

MRI identifies biochemical alterations of intervertebral discs in patients with low back pain and radiculopathy

Key Points

• Molecular intervertebral disc damage was associated with LBP and radiculopathy.

• Patients with radiculopathy and LBP demonstrated a depletion of gagCEST values compared with healthy controls.

• GagCEST imaging may be a non-invasive tool for investigation of degeneration processes of lumbar intervertebral discs (IVDs). GagCEST imaging may be an imaging biomarker for biochemical IVD alterations.

How patient off-centering impacts organ dose and image noise in pediatric head and thoracoabdominal CT

Abstract

Objectives

To assess the impact of patient off-centering on organ dose and image noise for head and thoracoabdominal CT in a pediatric phantom.

Methods

An anthropomorphic phantom simulating a 5-year-old child was used. Semiconductor dosimeters were placed in various cranial and thoracoabdominal organs. Head and thoracoabdominal CT were performed using automatic tube current modulation (ATCM) and default bowtie filters. The phantom was imaged repeatedly at vertical table positions ranging from − 6 to + 6 cm from the 0-position. Tube current time products (TCTP), organ doses, and image noise were recorded. Scatter radiation was measured in the thyroid for head CT. The effect of ATCM and bowtie filters was assessed.

Results

Depending on patient position, organ doses differed up to 22% for the supratentorial brain, 34% for the infratentorial brain, 19% for the eyes, 28% for the lungs, 25% for the stomach, and 22% for the liver compared with those in the 0-position. The relation between position and dose was linear and mainly affected by the bowtie filter in head CT, while it was quadratic and affected by ATCM and bowtie filter in thoracoabdominal CT. It further depended on the relative position of each organ to the isocenter. An inverse relation was found between position and image noise. Scatter radiation was not significantly related to patient positioning (p = 0.21).

Conclusions

In pediatric CT, vertical patient positioning had a substantial impact on radiation dose with differences of up to 34%, depending on the body region and location of each individual organ.

Key Points

• Patient off-centering has a substantial impact on organ radiation dose and image noise in pediatric CT.

• Impact of patient off-centering on radiation dose and noise differs between head and thoracoabdominal CT.

• Differences are caused by both ATCM and bowtie filter in thoracoabdominal CT, but mainly by bowtie filter in head CT.

Temporal subtraction of computed tomography images improves detectability of bone metastases by radiology residents

Abstract

Objective

Temporal subtraction of CT (TS) images improves detection of newly developed bone metastases (BM). We sought to determine whether TS improves detection of BM by radiology residents as well.

Methods

We performed an observer study using a previously reported dataset, consisting of 60 oncology patients, each with previous and current CT images. TS images were calculated using in-house software. Four residents independently interpreted twice the 60 sets of CT images, without and with TS. They identified BM by marking suspicious lesions likely to be BM. Lesion-based sensitivity and number of false positives per patient were calculated. Figure-of-merit (FOM) was calculated. Detectability of BM, with and without TS, was compared between radiology residents and board-certified radiologists, as published previously.

Results

FOM of residents significantly improved by implementing TS (p value < 0.0001). Lesion-based sensitivity, false positives per patients, and FOM were 40.8%, 0.121, and 0.657, respectively, without TS, and 58.1%, 0.0958, and 0.796, respectively, with TS. These findings were comparable with the previously published values for board-certified radiologists without TS (58.0%, 0.19, and 0.758, respectively).

Conclusion

The detectability of BM by residents improved markedly by implementing TS and reached that of board-certified radiologists without TS.

Key Points

• Detectability of bone metastases on CT by residents improved significantly when using temporal subtraction of CT (TS).

• Detections by residents with TS and board-certified radiologists without TS were comparable.

• TS is useful for residents as it is for board-certified radiologists.

CT texture analysis in the differentiation of major renal cell carcinoma subtypes and correlation with Fuhrman grade

Abstract

Objective

CT texture analysis (CTTA) using filtration-histogram–based parameters has been associated with tumor biologic correlates such as glucose metabolism, hypoxia, and tumor angiogenesis. We investigated the utility of these parameters for differentiation of clear cell from papillary renal cancers and prediction of Fuhrman grade.

Methods

A retrospective study was performed by applying CTTA to pretreatment contrast-enhanced CT scans in 290 patients with 298 histopathologically confirmed renal cell cancers of clear cell and papillary types. The largest cross section of the tumor on portal venous phase axial CT was chosen to draw a region of interest. CTTA comprised of an initial filtration step to extract features of different sizes (fine, medium, coarse spatial scales) followed by texture quantification using histogram analysis.

Results

A significant increase in entropy with fine and medium spatial filters was demonstrated in clear cell RCC (p = 0.047 and 0.033, respectively). Area under the ROC curve of entropy at fine and medium spatial filters was 0.804 and 0.841, respectively. An increased entropy value at coarse filter correlated with high Fuhrman grade tumors (p = 0.01). The other texture parameters were not found to be useful.

Conclusion

Entropy, which is a quantitative measure of heterogeneity, is increased in clear cell renal cancers. High entropy is also associated with high-grade renal cancers. This parameter may be considered as a supplementary marker when determining aggressiveness of therapy.

Key points

• CT texture analysis is easy to perform on contrast-enhanced CT.

• CT texture analysis may help to separate different types of renal cancers.

• CT texture analysis may enhance individualized treatment of renal cancers.

Impact of sublingual nitroglycerin dosage on FFR CT assessment and coronary luminal volume–to–myocardial mass ratio

Abstract

Objectives

Fractional flow reserve computed tomography (FFR_CT) depends upon nitroglycerin (NTG) inducing maximal hyperemia. However, the impact of NTG dosages on FFR_CT analysis including coronary volume–to–mass ratio (V/M) is unknown.

Methods

Eighty patients with repeat coronary CT angiograms (CCTAs) with different sublingual spray NTG doses (0.4 mg and 0.8 mg) were retrospectively analyzed with 45 patients excluded. Patient and scan demographics, post-stenosis and nadir FFR_CT values, coronary volume, and coronary volume–to–mass ratio (V/M) were compared at initial CCTA (0.4 mg NTG) and follow-up CCTA (0.8 mg NTG). Differences were compared by Wilcoxon signed-rank test.

Results

Thirty-five patients were included (time between CCTAs, 3.9 ± 1.6 years). Segment involvement score was 2.4 ± 3.3 and 2.8 ± 3.4 at initial and repeat CCTA (0.4 and 0.8 mg NTG), respectively (p = 0.004). There was similar image quality (4.1 ± 0.7 vs 4.1 ± 0.8; p = 0.51). Nadir FFR_CT values did not differ in the left (0.4 mg, 0.80 ± 0.08 vs 0.8 mg, 0.80 ± 0.03; p = 0.66), right (0.4 mg, 0.90 ± 0.04 vs 0.8 mg, 0.90 ± 0.06; p = 0.25), or circumflex coronaries (0.4 mg, 0.87 ± 0.06 vs 0.8 mg, 0.88 ± 0.06; p = 0.34). Post-stenosis FFR_CT values did not differ (p = 0.65). Coronary volume increased with 0.8 mg of NTG (2639 ± 753 mm³ vs 2844.8 ± 827 mm³; p = 0.009) but V/M ratio did not (p = 0.20).

Conclusions

Use of 0.8 mg versus 0.4 mg of NTG in routine clinical CCTAs significantly increased coronary volume determined from FFR_CT analysis but did not alter FFR_CT or V/M. Further evaluation of repeat CCTAs in a more contemporaneous fashion using varied nitrate doses and disease severity is needed.

Key Points

• Fractional flow reserve from computed tomography (FFR_CT) is a noninvasive method for evaluating the coronary arteries and relies on nitroglycerin (NTG) to induce coronary vasodilation, but the impact of different NTG dosages is unknown.

• Retrospective analysis evaluated use of different NTG doses on FFR_CT.

• Increased NTG dose increased coronary luminal volume on FFR_CTanalysis, but did not change FFR_CTvalues.

MRI identifies biochemical alterations of intervertebral discs in patients with low back pain and radiculopathy

Key Points

• Molecular intervertebral disc damage was associated with LBP and radiculopathy.

• Patients with radiculopathy and LBP demonstrated a depletion of gagCEST values compared with healthy controls.

• GagCEST imaging may be a non-invasive tool for investigation of degeneration processes of lumbar intervertebral discs (IVDs). GagCEST imaging may be an imaging biomarker for biochemical IVD alterations.

How patient off-centering impacts organ dose and image noise in pediatric head and thoracoabdominal CT

Abstract

Objectives

To assess the impact of patient off-centering on organ dose and image noise for head and thoracoabdominal CT in a pediatric phantom.

Methods

An anthropomorphic phantom simulating a 5-year-old child was used. Semiconductor dosimeters were placed in various cranial and thoracoabdominal organs. Head and thoracoabdominal CT were performed using automatic tube current modulation (ATCM) and default bowtie filters. The phantom was imaged repeatedly at vertical table positions ranging from − 6 to + 6 cm from the 0-position. Tube current time products (TCTP), organ doses, and image noise were recorded. Scatter radiation was measured in the thyroid for head CT. The effect of ATCM and bowtie filters was assessed.

Results

Depending on patient position, organ doses differed up to 22% for the supratentorial brain, 34% for the infratentorial brain, 19% for the eyes, 28% for the lungs, 25% for the stomach, and 22% for the liver compared with those in the 0-position. The relation between position and dose was linear and mainly affected by the bowtie filter in head CT, while it was quadratic and affected by ATCM and bowtie filter in thoracoabdominal CT. It further depended on the relative position of each organ to the isocenter. An inverse relation was found between position and image noise. Scatter radiation was not significantly related to patient positioning (p = 0.21).

Conclusions

In pediatric CT, vertical patient positioning had a substantial impact on radiation dose with differences of up to 34%, depending on the body region and location of each individual organ.

Key Points

• Patient off-centering has a substantial impact on organ radiation dose and image noise in pediatric CT.

• Impact of patient off-centering on radiation dose and noise differs between head and thoracoabdominal CT.

• Differences are caused by both ATCM and bowtie filter in thoracoabdominal CT, but mainly by bowtie filter in head CT.

Temporal subtraction of computed tomography images improves detectability of bone metastases by radiology residents

Abstract

Objective

Temporal subtraction of CT (TS) images improves detection of newly developed bone metastases (BM). We sought to determine whether TS improves detection of BM by radiology residents as well.

Methods

We performed an observer study using a previously reported dataset, consisting of 60 oncology patients, each with previous and current CT images. TS images were calculated using in-house software. Four residents independently interpreted twice the 60 sets of CT images, without and with TS. They identified BM by marking suspicious lesions likely to be BM. Lesion-based sensitivity and number of false positives per patient were calculated. Figure-of-merit (FOM) was calculated. Detectability of BM, with and without TS, was compared between radiology residents and board-certified radiologists, as published previously.

Results

FOM of residents significantly improved by implementing TS (p value < 0.0001). Lesion-based sensitivity, false positives per patients, and FOM were 40.8%, 0.121, and 0.657, respectively, without TS, and 58.1%, 0.0958, and 0.796, respectively, with TS. These findings were comparable with the previously published values for board-certified radiologists without TS (58.0%, 0.19, and 0.758, respectively).

Conclusion

The detectability of BM by residents improved markedly by implementing TS and reached that of board-certified radiologists without TS.

Key Points

• Detectability of bone metastases on CT by residents improved significantly when using temporal subtraction of CT (TS).

• Detections by residents with TS and board-certified radiologists without TS were comparable.

• TS is useful for residents as it is for board-certified radiologists.

CT texture analysis in the differentiation of major renal cell carcinoma subtypes and correlation with Fuhrman grade

Abstract

Objective

CT texture analysis (CTTA) using filtration-histogram–based parameters has been associated with tumor biologic correlates such as glucose metabolism, hypoxia, and tumor angiogenesis. We investigated the utility of these parameters for differentiation of clear cell from papillary renal cancers and prediction of Fuhrman grade.

Methods

A retrospective study was performed by applying CTTA to pretreatment contrast-enhanced CT scans in 290 patients with 298 histopathologically confirmed renal cell cancers of clear cell and papillary types. The largest cross section of the tumor on portal venous phase axial CT was chosen to draw a region of interest. CTTA comprised of an initial filtration step to extract features of different sizes (fine, medium, coarse spatial scales) followed by texture quantification using histogram analysis.

Results

A significant increase in entropy with fine and medium spatial filters was demonstrated in clear cell RCC (p = 0.047 and 0.033, respectively). Area under the ROC curve of entropy at fine and medium spatial filters was 0.804 and 0.841, respectively. An increased entropy value at coarse filter correlated with high Fuhrman grade tumors (p = 0.01). The other texture parameters were not found to be useful.

Conclusion

Entropy, which is a quantitative measure of heterogeneity, is increased in clear cell renal cancers. High entropy is also associated with high-grade renal cancers. This parameter may be considered as a supplementary marker when determining aggressiveness of therapy.

Key points

• CT texture analysis is easy to perform on contrast-enhanced CT.

• CT texture analysis may help to separate different types of renal cancers.

• CT texture analysis may enhance individualized treatment of renal cancers.

Impact of sublingual nitroglycerin dosage on FFR CT assessment and coronary luminal volume–to–myocardial mass ratio

Abstract

Objectives

Fractional flow reserve computed tomography (FFR_CT) depends upon nitroglycerin (NTG) inducing maximal hyperemia. However, the impact of NTG dosages on FFR_CT analysis including coronary volume–to–mass ratio (V/M) is unknown.

Methods

Eighty patients with repeat coronary CT angiograms (CCTAs) with different sublingual spray NTG doses (0.4 mg and 0.8 mg) were retrospectively analyzed with 45 patients excluded. Patient and scan demographics, post-stenosis and nadir FFR_CT values, coronary volume, and coronary volume–to–mass ratio (V/M) were compared at initial CCTA (0.4 mg NTG) and follow-up CCTA (0.8 mg NTG). Differences were compared by Wilcoxon signed-rank test.

Results

Thirty-five patients were included (time between CCTAs, 3.9 ± 1.6 years). Segment involvement score was 2.4 ± 3.3 and 2.8 ± 3.4 at initial and repeat CCTA (0.4 and 0.8 mg NTG), respectively (p = 0.004). There was similar image quality (4.1 ± 0.7 vs 4.1 ± 0.8; p = 0.51). Nadir FFR_CT values did not differ in the left (0.4 mg, 0.80 ± 0.08 vs 0.8 mg, 0.80 ± 0.03; p = 0.66), right (0.4 mg, 0.90 ± 0.04 vs 0.8 mg, 0.90 ± 0.06; p = 0.25), or circumflex coronaries (0.4 mg, 0.87 ± 0.06 vs 0.8 mg, 0.88 ± 0.06; p = 0.34). Post-stenosis FFR_CT values did not differ (p = 0.65). Coronary volume increased with 0.8 mg of NTG (2639 ± 753 mm³ vs 2844.8 ± 827 mm³; p = 0.009) but V/M ratio did not (p = 0.20).

Conclusions

Use of 0.8 mg versus 0.4 mg of NTG in routine clinical CCTAs significantly increased coronary volume determined from FFR_CT analysis but did not alter FFR_CT or V/M. Further evaluation of repeat CCTAs in a more contemporaneous fashion using varied nitrate doses and disease severity is needed.

Key Points

• Fractional flow reserve from computed tomography (FFR_CT) is a noninvasive method for evaluating the coronary arteries and relies on nitroglycerin (NTG) to induce coronary vasodilation, but the impact of different NTG dosages is unknown.

• Retrospective analysis evaluated use of different NTG doses on FFR_CT.

• Increased NTG dose increased coronary luminal volume on FFR_CTanalysis, but did not change FFR_CTvalues.

Correction to: Epicardial fat volume measured on nongated chest CT is a predictor of coronary artery disease The original version of this article, published on 11 March 2019, unfortunately contained a mistake. The following correction has therefore been made in the original: the presentation of Fig. 5 was incorrect. The corrected figure is given below.

Correction to: Anatomical variations in the origins of the celiac axis and the superior mesenteric artery: MDCT angiographic findings and their probable embryological mechanisms The original version of this article, published on 24 May 2014, unfortunately contained a referencing omission.

Correction to: Point estimate and reference normality interval of MRI-derived myocardial extracellular volume in healthy subjects: a systematic review and meta-analysis The original version of this article, published on 02 May 2019, unfortunately contained a mistake. The following correction has therefore been made in the original: The presentation of Fig. 2 was incorrect. The corrected figure is given below. The original article has been corrected.

Correction to: An analysis of 11.3 million screening tests examining the association between recall and cancer detection rates in the English NHS breast cancer screening programme The original version of this article, published on 04 February 2019, unfortunately contained a mistake.

Correction to: Diagnostic performance of dual-energy CT and subtraction CT for renal lesion detection and characterization The original version of this article, published on 27 May 2019, unfortunately contained a mistake. The following correction has therefore been made in the original.