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The aim of the study was to evaluate the diagnostic accuracy of carotid ultrasound (CU) to predict coronary atherosclerosis in asymptomatic male marathon runners. A total of 49 male marathon runners older than 45 years (mean age 53.3 ± 7.2 years, range 45-74 years) received CU and cardiac CT angiography (CTA) including calcium scoring (CS). Results of CU and CTA were classified binary: 1. Absence of atherosclerosis and 2. Presence of atherosclerosis. The extent of atherosclerosis was not primary end point of the study. Mean PROCAM score was 2.3% (SD 2.2, range 0.44%-12.34%). One person had to be excluded from analysis (one missing CT-scan). From the remaining 48 marathon runners, 17 (35.4%) had carotid atherosclerosis and 22 (45.8%) coronary atherosclerosis. Atherosclerosis in either exam was diagnosed in 27/48 (56.3%) marathon runners. Diagnostic accuracy of CU to predict coronary atherosclerosis was: sensitivity 54.55% (95% CI 32.2-75.6), specificity 80.8% (CI 60.6-93.4), positive predictive value 70.6 (CI 44.1-89.9), negative predictive value 67.7 (CI 48.6-83.3) with a positive likelihood ratio of 2.84 (CI 1.18-6.82) and a negative likelihood ratio of 0.56 (CI 0.34-0.92). Coronary and/or carotid atherosclerosis can be detected in more than 50% of male marathon runners aged older than 45 years. The diagnostic value of carotid ultrasound to predict coronary atherosclerosis is low but higher than the accuracy of rest- or stress-ECG. As outcome studies in sportsmen are still missing, the routine evaluation of the carotid arteries by ultrasound or even cardiac CT cannot be recommended at present. Furthermore, the incidence of atherosclerosis by our method in normal population is not known.

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PURPOSE: The impact of preoperative MRI on re-excisions and mastectomy rate is discussed controversially in the literature. Aim of this study was to evaluate the effect of preoperative breast MRI on the surgical procedure and rate of repeated surgeries. MATERIAL AND METHODS: A total of 991 consecutive patients in the years 2009 and 2010 with 1036 primary breast cancers were retrospectively analyzed. Sixty percent (599 patients with 626 cancers) received preoperative breast MRI. Planned surgical procedures before and after MRI and numbers of repeated surgeries in patients with (MR+ ) and without preoperative MRI (MR-) were compared. RESULTS: The result of preoperative MRI changed the surgical procedure in 25% (157/626) of the cases. In 81% (127/157), MRI was beneficial for the patients, as otherwise occult carcinomas were removed (n=122) or further biopsy could be prevented (n=5). Mastectomy rates did not differ between MR+ and MR- group (39% vs. 39%). On multiple regression analysis, the MR+ group had a lower chance for repeated surgery (p<0.05). CONCLUSION: Preoperative MRI could lower the chance for repeated surgery in patients with primary breast cancer. The rate of mastectomy did not differ between patients undergoing preoperative MRI and those who did not.

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BACKGROUND: Combined MRI/PET enables the acquisition of a variety of imaging parameters during one examination, including anatomical and functional information such as perfusion, diffusion, and metabolism. OBJECTIVE: The present article summarizes these methods and their applications in multiparametric imaging via MRI/PET. RESULTS: Numerous studies have shown that the combination of these parameters can improve diagnostic accuracy for many applications, including the imaging of oncological, neurological, and inflammatory conditions. Because of the amount and the complexity of the acquired multiparametric data, there is a need for advanced analysis tools, such as methods of parameter selection and data classification. DISCUSSION: Currently, the clinical application of this process still has limitations. On the one hand, software for the fast calculation and standardized evaluation of the imaging data acquired is still lacking. On the other hand, there are deficiencies when comparing the results because of a lack of standardization of the assessment and diagnostic procedure.

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PURPOSE: To evaluate the prevalence of coronary artery disease (CAD) in middle-aged, male marathon runners using coronary dual source CT angiography (DSCTA). MATERIALS AND METHODS: 50 male marathon runners older than 45 years (mean age: 52.7, standard deviation: 5.9 years, range: 45 to 67 years) received DSCTA including calcium scoring (CS) in addition to standard pre-participation screening. Based on standard risk factors, the risk for coronary events was calculated using the PROCAM score. Coronary status was defined using the following system: 1. absence of CAD (CS zero, no coronary plaques) 2. mild coronary atherosclerosis (CS > 0, coronary plaques with luminal narrowing < 50 %), 3. moderate coronary atherosclerosis (CS > 0, luminal narrowing > 50 %), 4. significant CAD (CS > 0, luminal narrowing > 75 %). RESULTS: The mean PROCAM score was 1.85 % (standard deviation = 1.56, range 0.39 to 8.47 %). 26/50 marathon runners had no atherosclerosis. 1 of the remaining 24 participants had significant CAD, 3 had moderate coronary atherosclerosis and 20 had mild coronary atherosclerosis. Treadmill exercise testing was unremarkable in terms of myocardial ischemia in all participants. Age, systolic blood pressure, personal minimum time, family history of cardiovascular disease and PROCAM score were factors associated with an increased risk for coronary atherosclerosis. CONCLUSION: Coronary atherosclerosis can be detected in almost 50 % of male marathon runners aged older than 45 years. In 24 % of the participants plaques were located in the proximal coronary system. However, only a minority of these persons have obstructive CAD. As expected, treadmill exercise testing failed to detect these persons that possibly have a higher risk for coronary events. KEY POINTS: • Coronary atherosclerosis can be detected in ~50 % of male marathon runners > 45 years. • Only a minority of these persons have obstructive CAD. • Treadmill exercise testing failed to detect these persons. • Cardiac CT might help to identify athletes with elevated risk for coronary events, especially in persons with a family history of coronary artery.

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This paper summarises the proceedings and discussions at the third annual workshop held in Tübingen, Germany, dedicated to the advancement of the technical, scientific and clinical applications of combined PET/MRI systems in humans. Two days of basic scientific and technical instructions with "hands-on" tutorials were followed by 3 days of invited presentations from active researchers in this and associated fields augmented by round-table discussions and dialogue boards with specific themes. These included the use of PET/MRI in paediatric oncology and in adult neurology, oncology and cardiology, the development of multi-parametric analyses, and efforts to standardise PET/MRI examinations to allow pooling of data for evaluating the technology. A poll taken on the final day demonstrated that over 50 % of those present felt that while PET/MRI technology underwent an inevitable slump after its much-anticipated initial launch, it was now entering a period of slow, progressive development, with new key applications emerging. In particular, researchers are focusing on exploiting the complementary nature of the physiological (PET) and biochemical (MRI/MRS) data within the morphological framework (MRI) that these devices can provide. Much of the discussion was summed up on the final day when one speaker commented on the state of PET/MRI: "the real work has just started".

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The aim of this cohort study was to assess the risk of developing cancer, specifically leukaemia, tumours of the central nervous system and lymphoma, before the age of 15 years in children previously exposed to computed tomography (CT) in Germany. Data for children with at least one CT between 1980 and 2010 were abstracted from 20 hospitals. Cancer cases occurring between 1980 and 2010 were identified by stochastic linkage with the German Childhood Cancer Registry (GCCR). For all cases and a sample of non-cases, radiology reports were reviewed to assess the underlying medical conditions at time of the CT. Cases were only included if diagnosis occurred at least 2 years after the first CT and no signs of cancer were recorded in the radiology reports. Standardised incidence ratios (SIR) using incidence rates from the general population were estimated. The cohort included information on 71,073 CT examinations in 44,584 children contributing 161,407 person-years at risk with 46 cases initially identified through linkage with the GCCR. Seven cases had to be excluded due to signs possibly suggestive of cancer at the time of first CT. Overall, more cancer cases were observed (O) than expected (E), but this was mainly driven by unexpected and possibly biased results for lymphomas. For leukaemia, the SIR (SIR = O/E) was 1.72 (95 % CI 0.89-3.01, O = 12), and for CNS tumours, the SIR was 1.35 (95 % CI 0.54-2.78, O = 7). Despite careful examination of the medical information, confounding by indication or reverse causation cannot be ruled out completely and may explain parts of the excess. Furthermore, the CT exposure may have been underestimated as only data from the participating clinics were available. This should be taken into account when interpreting risk estimates.

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BACKGROUND: Three-vessel coronary artery disease (CAD) comes along with globally reduced myocardial perfusion potentially restricting the demarcation of regional hypoperfusion in stress perfusion cardiac magnetic resonance imaging (MRI). PURPOSE: To evaluate whether stress perfusion cardiac MRI is capable of detecting myocardial hypoperfusion in patients with 3-vessel CAD reliably. MATERIAL AND METHODS: Two hundred and five patients with symptoms of CAD were included. The examination protocol comprised imaging of myocardial perfusion at stress (0.14 mg/kg/min adenosine for 4 min) using a 2D saturation recovery gradient echo sequence after administration of gadobutrol (0.1 mmol/kg body weight). Perfusion sequences were assessed qualitatively by two experienced observers. Coronary angiography served as standard of reference. RESULTS: Sensitivity and specificity for hemodynamically relevant stenoses in patients with 0-, 1-, 2-, 3-vessel coronary artery disease were 100%/91%, 91%/73%, 90%/71%, 92%/64%; positive/negative predictive value, 67%/100%, 91%/73%, 83%/81%, 93%/58%; diagnostic accuracy, 93%/87%/83%/87%, respectively. The negative predictive value in patients with 3-vessel CAD was lower than in patients with 0- and 2-vessel CAD and the specificity lower than in patients with no CAD whereas the positive predictive value was higher than in patients with no CAD. The other proportions did not differ significantly between the groups. CONCLUSION: The diagnostic value of stress perfusion cardiac MRI in patients with 3-vessel CAD is comparable to results in patients with 1- or 2-vessel CAD. In the rare event that stress perfusion images do not depict regional hypoperfusion in patients with severe 3-vessel CAD, myocardial ischemia could be identified by reduced semi-quantitative perfusion parameters.

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OBJECTIVE: To assess feasibility of whole-body diffusion-weighted MRI (wbDWI) for very early evaluation of response to therapy in different lymphoma subtypes. MATERIALS AND METHODS: 20 patients (10 male, 10 female; mean age 50.7±16.1±17.2 years) underwent wbDWI (calculation of apparent diffusion coefficient [ADC] with b=0, 800s/mm(2)) at baseline and within a median of 7 days after therapy onset. Lymphoma manifestations were evaluated with respect to changes in ADC and size at follow-up with up to six of the largest lesions per patient undergoing quantification. An increase in ADC as well as a decrease in size at follow-up was classified as responder, whereas neither change in ADC nor in size (or progression) was considered non-responder. Results were confirmed at interim measurements (after 3-4 chemotherapy cycles) and 6 months after treatment. RESULTS: 90 lymphoma lesions were analyzed. 18 patients were classified as responders and 2 as non-responder at FU (mean, 1 week). DWI results accurately (100%) correlated with the subsequent interim course of all lesions. mean baseline ADC was 0.79±0.28×10(-3)s/mm(2). For responders mean follow-upADC increased by 64.6±56.5% (p<0.001) whereas lesions size decreased by mean 14.4±13.3% (p<0.001). In the non-responder, both values did not significantly change. In patients classified as responders six months after treatment, meanADC increase at FU was 70.3±57.8% (p<0.001) whereas mean size decrease vs. baseline was 15.8±13.6% as compared to non-responders (22.4±39.9%) and 5.4±0.9%, respectively. CONCLUSION: wbDWI with ADC analysis represents a feasible diagnostic tool for very early response assessment in lymphoma patients enabling also prediction of long-term response.

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OBJECTIVES: The aim of this study was to evaluate the accuracy of preoperative magnetic resonance imaging (MRI) in the diagnosis of malformations associated with Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome and identification of uterine endometrium to optimise the clinical management. METHODS: We retrospectively reviewed 214 consecutive MRKH patients, mean age 19 years, who underwent laparoscopy-assisted neovagina creation. A total of 115 patients (53.7%) met the inclusion criterion of sufficient preoperative MRI. In 110 of them (95.7%), MRI findings were correlated with laparoscopy and associated malformations. In 39 cases (35.5%) uterine rudiments were removed and analysed histopathologically. RESULTS: Ten per cent (11/110) of the patients showed complete uterine agenesis. The others presented with either unilateral (n = 16; 14.5%) or bilateral (n = 83; 75.5%) uterine rudiments. MRI detection of uterine rudiments agreed in 78.2% (86/110) with laparoscopy. In 85.4% of the removed rudiments, MRI could correctly diagnose the existence of the endometrium. Compared to laparoscopy, MRI could exactly detect ovaries in 97.3% (107/110). Renal or ureteral malformations were seen in 32 cases (27.8%). In 83% of unilateral renal agenesis and unilateral rudiment, the latter was located at the side of the kidney. CONCLUSIONS: MRI is useful for preoperative detection of MRKH-associated malformations and assessment of the endometrium to further optimise MRKH patient treatment. KEY POINTS: • Pelvic MRI is useful for preoperative detection of MRKH-associated malformations. • MRI can diagnose uterine endometrium in MRKH patients with high precision. • Preoperative MRI can optimise clinical management of patients with MRKH syndrome.

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UNLABELLED: Since the introduction of endovascular aneurysm repair (EVAR) in 1991, the endovascular therapy with newest stent grafts has assumed a prominent role in the clinical management of abdominal aortic aneurysms (AAA) with a superior perioperative mortality of EVAR and an equivalent mid-term outcome, compared to open surgery. Newest techniques using chimney or periscope grafts and customized fenestrated and branched stent grafts allow the endovascular treatment of complex pararenal AAA. This article reviews EVAR in the treatment of AAA, evidence based results and advanced indication by newest interventional techniques and technical developments. KEY POINTS: • EVAR has become standard treatment of abdominal aortic aneurysm with equivalent results to open surgery.• Technical advancements and the introduction of newest stent grafts continually expand the indication of EVAR.• Chimney- and periscope grafts as well as custom-made prothesis systems allow endovascular treatment of complex para- and suprarenal aneurysms.

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PURPOSE: In patients with peritoneal carcinomatosis (PC), cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is an evolving therapeutic approach with curative intention. The differentiation between posttherapeutic findings after HIPEC and relapse of PC is challenging. We evaluated the diagnostic value of F-18-FDG-PET/CT in patients with relapse of PC after HIPEC. MATERIALS AND METHODS: 36 patients with recurring PC after HIPEC were examined on a whole-body PET/CT system (44 examinations). The examination included 3 D F-18-FDG-PET and contrast-enhanced CT. Images were assessed by two experienced readers regarding the presence and the extent of PC using the peritoneal carcinomatosis index (PCI). Imaging results were correlated with surgical findings or follow-up. RESULTS: Relapse was suspected in 40 of 44 examinations. Relapse was missed by F-18-FDG PET/CT in 4 patients and significantly underestimated in 8 patients. The diagnostic accuracy for the detection of PC on a patient basis was 91 %, the sensitivity was 91 % and the positive predictive value was 100 %. The mean PCI was 11.4 ±â€Š11.9 for PET/CT, 8.4 ±â€Š10.3 for CT and 16.6 ±â€Š15.0 in the case of surgical exploration. The extent of PC was underestimated by PET/CT and even more by CT alone (p < 0.05). CONCLUSION: The diagnostic value of F-18-FDG PET/CT after cytoreductive surgery and HIPEC in the detection of recurring PC is superior to contrast-enhanced CT. However, the quantification of the extent of PC is limited due to post-therapeutic tissue alterations. KEY POINTS: • Imaging of recurrent PC after HIPEC is challenging due to posttherapeutic tissue alterations.• The extent of recurrent PC after HIPEC is systematically underestimated by F-18-FDG PET/CT.• F-18-FDG PET/CT provides improved sensitivity for recurrent PC compared to contrast-enhanced CT.• The correlation of the extent of recurrent PC depicted by F-18-FDG PET/CT and surgical exploration is better than that of contrast-enhanced CT and surgical exploration.

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AIM: To evaluate whether another contrast-enhanced (CE) magnetic resonance imaging (MRI) examination 24-48 h after MRI-guided vacuum-assisted breast biopsy (MRI-VAB) can reduce the rate of false-negative cases. MATERIALS AND METHODS: The study included 252 patients who underwent MRI-VAB for the clarification of 299 lesions. The success of MRI-VAB was assessed at interventional MRI and another CE MRI 24-48 h after the intervention. In cases of successful MRI-VAB (complete or partial lesion removal) and benign histological results, follow-up breast MRI was performed. In cases of unsuccessful biopsy (unchanged lesion), tissue sampling was repeated. False-negative cases were calculated to assess the diagnostic value of MRI follow-up within 2 days after intervention. RESULTS: Ninety-eight malignant (32.8%) and 201 (67.2%) benign lesions were diagnosed using MRI-VAB. At immediate unenhanced control MRI, all lesions were assessed as successfully biopsied. In 18 benign cases (6%), CE MRI after 24-48 h showed an unsuccessful intervention. Further tissue sampling revealed another 13 cancers in these patients. This results in a false-negative rate of 11.7%. Follow-up MRI of the benign lesions presented no further malignancy. CONCLUSIONS: MRI-VAB with immediate unenhanced control offers a success rate of 94%. The rate of false-negative biopsies (11.7%) could be reduced to zero by using short-term follow-up MRI. Therefore, a further CE breast MRI 24-48 h after benign MRI-VAB to eliminate missed cancers is recommended.

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PURPOSE: Energy transfer from radiofrequency (RF) applicator to tissue is both precondition and limiting factor. The purpose of this ex vivo study was to examine the influence of form of energy delivery on ablation result during RF ablation with cryo-cooled applicators. MATERIALS AND METHODS: One hundred eight ablations were performed in ex vivo bovine liver under continuous energy delivery (A), pulsed energy delivery with reduced current during ablation pause (B) and impedance-dependent energy delivery. Maximum ablation time was 20 min. Early termination of ablation in case of loss of conductivity. Optimal ablation parameters were assessed. Short axis diameter of the ablation zone and ablation duration were determined. Ablation results under mode A, B and C were compared with analysis of variance and Tukey-Kramer HSD test. Influence of ablation duration on short axis diameter was evaluated with regression analysis. RESULTS: Significantly largest short axis diameter (51.1 mm ± SD 2.3; p = 0.01) was reached with impedance-dependent energy delivery (pulsed: 46.1 mm ± SD 5.6; continuous: 44.4 mm ± SD 4.1). Significantly longest ablation duration (1061.6 s ± SD 42.4; p = 0.01) was reached with impedance-dependent energy delivery (pulsed: 815.7 s ±â€Š41.3; continuous: 715.3 s ± SD 82.2). Linear correlation between ablation duration and short axis diameter was calculated (R = 0.7). CONCLUSION: Modification of energy delivery during RF ablation with cryo-cooled applicators improves energy transfer to tissue and enables larger ablation zones. KEY POINTS: • Impedance-dependent energy delivery prevents early termination in kryo-based RF-ablation,• Impedance-dependent energy delivery enables larger ablation zones than continuous energy delivery,• Reduced current during ablation pause does not improve ablation results.

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PURPOSE: To evaluate a novel monoenergetic post-processing algorithm (MEI+) in patients with poor intrahepatic contrast enhancement. MATERIALS AND METHODS: 25 patients were retrospectively included in this study. Late-phase imaging of the upper abdomen, which was acquired in dual-energy mode (100/140 kV), was used as a model for poor intrahepatic contrast enhancement. Traditional monoenergetic images (MEI), linearly weighted mixed images with different mixing ratios (MI), sole 100 and 140 kV and MEI+ images were calculated. MEI+ is a novel technique which applies frequency-based mixing of the low keV images and an image of optimal keV from a noise perspective to combine the benefits of both image stacks. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the intrahepatic vasculature (IHV) and liver parenchyma (LP) were objectively measured and depiction of IHV was subjectively rated and correlated with portal venous imaging by two readers in consensus. RESULTS: MEI+ was able to increase the SNR of the IHV (5.7 ±â€Š0.4 at 40keV) and LP (4.9 ±â€Š1.0 at 90keV) and CNR (2.1 ±â€Š0.6 at 40keV) greatly compared to MEI (5.1 ±â€Š1.1 at 80keV, 4.7 ±â€Š1.0 at 80keV, 1.0 ±â€Š0.4 at 70keV), MI (5.2 ±â€Š1.1 M5:5, 4.8 ±â€Š1.0 M5:5, 1.0 ±â€Š3.5 M9:1), sole 100 kV images (4.4 ±â€Š1.0, 3.7 ±â€Š0.8, 1.0 ±â€Š0.3) and 140 kV images (2.8 ±â€Š0.5, 3.1 ±â€Š0.6, 0.1 ±â€Š0.2). Subjective assessment rated MEI+ of virtual 40 keV superior to all other images. CONCLUSION: MEI+ is a very promising algorithm for monoenergetic extrapolation which is able to overcome noise limitations associated with traditional monoenergetic techniques at low virtual keV levels and consequently does not suffer from a decline of SNR and CNR at low keV values. This algorithm allows an improvement of IHV depiction in the presence of poor contrast. KEY POINTS: • The evaluated new image-based algorithm for virtual monoenergetic imaging allows calculating low virtual keV images from dual energy datasets with significantly improved contrast-to-noise ratios. • The image based novel monoenergetic extrapolation algorithm applies frequency-based mixing of the low keV images and an image of optimal keV from a noise perspective to combine the benefits of both image stacks.• When compared to traditional monoenergetic images, the novel monoenergetic algorithm has improved contrast-to-noise ratios for both low and high virtual keV images.• Contrast-enhanced dual energy images with poor contrast conditions can be significantly improved, e.g. late phase imaging of the liver.

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PURPOSE: The aim of this study was to investigate frequencies of typical artifacts in low-dose pediatric lung examinations using high-pitch computed tomography (HPCT) compared to MDCT, and to estimate the effective radiation dose (Eeff). MATERIALS AND METHODS: Institutional review board approval for this retrospective study was obtained. 35 patients (17 boys, 18 girls; mean age 112 ±â€Š69 months) were included and underwent MDCT and follow-up scan by HPCT or vice versa (mean follow-up time 87 days), using the same tube voltage and current. The total artifact score (0 - 8) was defined as the sum of artifacts arising from movement, breathing or pulsation of the heart or pulmonary vessels (0 - no; 1 - moderate; 2 - severe artifacts). Eeff was estimated according to the European Guidelines on Quality Criteria for Multislice Computed Tomography. The Mann-Whitney U test was used to analyze differences between the patient groups. The Spearman's rank correlation coefficient was used for correlation of ordinal variables. RESULTS: The scan time was significantly lower for HPCT compared to MDCT (0.72 ±â€Š0.13 s vs. 3.65 ±â€Š0.81s; p < 0.0001). In 28 of 35 (80 %) HPCT examinations no artifacts were visible, whereas in MDCT artifacts occurred in all examinations. The frequency of pulsation artifacts and breathing artifacts was higher in MDCT compared to HPCT (100 % vs. 17 % and 31 % vs. 6 %). The total artifact score significantly correlated with the patient's age in MDCT (r = - 0.42; p = 0.01), but not in HPCT (r = - 0.32; p = 0.07). The estimated Eeff was significantly lower in HPCT than in MDCT (1.29 ±â€Š0.31 vs. 1.47 ±â€Š0.37 mSv; p < 0.0001). CONCLUSION: Our study indicates that the use of HPCT has advantages for pediatric lung imaging with a reduction of breathing and pulsation artifacts. Moreover, the estimated Eeff was lower. In addition, examinations can be performed without sedation or breath-hold without losing image quality. KEY POINTS: • Fewer artifacts in pediatric lung imaging with HPCT• Reduced Eeff in HPCT• HPCT without sedation or breath-hold without loss of image quality.

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UNLABELLED: Breast MR imaging has become established as the most sensitive imaging method for diagnosing breast cancer. As a result of the increasing examination volume and improved image quality, the number of breast lesions detected only on MRI and requiring further clarification has risen in recent years. According to the S3-guideline "Diagnosis, Therapy, and Follow-Up of Breast Cancer" as revised in July 2012, institutions performing breast MRI should provide the option of an MRI-guided intervention for clarification. This review describes the indications, methods and results of MRI-guided interventions for the clarification of breast lesions only visible on MRI. Recent guidelines and study results are also addressed and alternative methods and pitfalls are presented. KEY POINTS: ▶ Up to 57 % of lesions originally visible only on MRI can be sonographically correlated and biopsied. ▶ MRI-guided intervention is necessary for the clarification of BI-RADS® 4 and 5 lesions detectable only on MRI ▶ MRI-guided vacuum-assisted breast biopsy should be preferentially used ▶ MRI-guided localization and surgical excision should be used if MRI-guided vacuum-assisted biopsy is not possible ▶ If BI-RADS® 4 and 5 findings visible only on MRI are not detectable on interventional MRI, a follow-up MRI should be performed within six months.

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OBJECTIVES: To determine the diagnostic benefit of volume perfusion computed tomography (VPCT) at end of treatment for response assessment in lymphoma patients. METHODS: Seventy-five patients with different lymphoma subtypes were included: 50/75 patients had residual masses at end of treatment, 26/50 patients underwent VPCT at baseline and at end of treatment, and 24/50 patients only had end-of-treatment VPCTs. We evaluated the size of the main lymphoma mass, its blood flow (BF), blood volume (BV) and k-trans, calculated ratios (baseline and end of treatment) as well as sensitivity/specificity/negative (NPV)/positive predictive values (PPV). For VPCT at end of treatment, a cutoff threshold between responders and non-responders was calculated. RESULTS: For patients undergoing VPCT at baseline and end of treatment, reduction in size, BF, BV and k-trans was significant (P < 0.001). Identification of non-response was reached at: <53% reduction in size (sensitivity/specificity/accuracy/PPV/NPV of 88.89%/62.5%/80.77%/84.21%/71.43%), <15% reduction of BF (sensitivity/specificity/accuracy/PPV/NPV of 100%/37.5%/80.77%/0.26%/100%), or <45% reduction of k-trans (sensitivity/specificity/accuracy/PPV/NPV of 88.89%/75%/84.62%/88.89%/75%). In the subgroup undergoing VPCT at end of treatment, BF >18.51 ml/100 ml indicated non-responsiveness (sensitivity 92.86%, specificity 72.73%, accuracy 84%, PPV 81.25%, NPV 88.89%). CONCLUSIONS: VPCT seems adequate for assessment of lymphoma response at end of treatment. The degree of residual lymphoma perfusion at end of treatment helps to identify patients likely to remain in remission 1 year after completion of therapy. KEY POINTS: • Volume perfusion computed tomography (VPCT) offers measurements for assessing tumour response. • Perfusion parameter changes measured by VPCT correlate with antitumour therapy response. • In lymphoma, baseline and end-of-treatment perfusion parameter ratios can predict response. • Perfusion measurements after treatment identify patients likely to remain in remission.

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